7ut51_v3 Acceptance Testing Commissioning and Maintenance Manual

7UT51 V3 Transformer Differential RelayAcceptance Testing,Commissioning and Maintenance Manual

Manual No. PRCM-1108A-0199

IMPORTANT

The information contained herein is general in nature and not intended forspecific application purposes. It does not relieve the user of responsibilityto use sound practices in application, installation, operation, and mainte-nance of the equipment purchased. Siemens reserves the right to makechanges at any time without notice or obligations. Should a conflict arisebetween the general information contained in this publication and the con-tents of drawings or supplementary material, or both, the latter shall takeprecedence.

NOTE

These instructions do not purport to cover all details or variations in equipment, nor to provide for every possi-ble contingency to be met in connection with installation, operation, or maintenance. Should further informationbe desired or should particular problems arise which are not covered sufficiently for the purchaser’s purposes,the matter should be referred to the local sales office.

The contents of the instruction manual shall not become part of or modify any prior or existing agreement,commitment or relationship. The sales contract contains the entire obligation of Siemens. The warranty con-tained in the contract between parties is the sole warranty of Siemens. Any statements contained herein do notcreate new warranties or modify the existing warranty.

QUALIFIED PERSON

For the purposes of this manual, a qualified person is one who is familiarwith the installation, construction, or operation of the equipment and thehazards involved. In addition, this person has the following qualifications:

(a) is trained and authorized to de-energize, clear, ground, and tag cir-cuits and equipment in accordance with established safety practices.

(b) is trained in the proper care and use of protective equipment such asrubber gloves, hard hat, safety glasses or face shields, flash clothing,etc., in accordance with established safety procedures.

(c) is trained in rendering first aid.

7UT51 v3

PRCM-1108A-0199 3

Contents

Table of Figures ............................................................................................................... ........................................ 6

Table of Tables................................................................................................................ ......................................... 7

Introduction ................................................................................................................... ........................................... 8

Definition of Terms ............................................................................................................ ...................................... 8

Understanding the Siemens 7UT51 Numerical Protective Relay..................................................................... . 10

Suggested Test Equipment....................................................................................................... ............................ 13

Siemens 7UT51 Relay Pre-Energization Checklist ................................................................................. ............ 14

Setting and Programming the Siemens 7UT51 Relay ................................................................................ ........ 15

Front Panel ........................................................................................................................................................... 15PC......................................................................................................................................................................... 15

Configuration Menu .......................................................................................................................................... 15Marshalling Menu ............................................................................................................................................. 15Settings Menu................................................................................................................................................... 15Additional Protective Functions ........................................................................................................................ 15

Important Notes about Transformers ................................................................................................................... 16Regulated Transformer..................................................................................................................................... 16FOA Transformers ............................................................................................................................................ 16

Accessing Data ................................................................................................................. ..................................... 17

Matching or Adaptation Factors ........................................................................................................................... 17Operational Annunciations (Event Log) Address Block 5100 .............................................................................. 19Network-Disturbance Annunciations (Fault Logs)................................................................................................ 19Operational Measured Values.............................................................................................................................. 20Waveform Data..................................................................................................................................................... 21

Acceptance Testing ............................................................................................................. .................................. 22

7UT51 Electrical Testing ...................................................................................................................................... 22Acceptance Testing .......................................................................................................................................... 22Installation Testing............................................................................................................................................ 22Testing for In-Service Setting Changes............................................................................................................ 22Evaluation Testing ............................................................................................................................................ 22Automated Testing............................................................................................................................................ 22Acceptance Test Equipment............................................................................................................................. 22Important Notes about the Procedure .............................................................................................................. 23

Transformer Differential Protection ...................................................................................................................... 25Test 1. Minimum Pickup of 87: Address 1603............................................................................................... 26Remaining Tests of the Differential Protection ................................................................................................. 26Test 2. Time Delay of 87 Tripping: Address 1625......................................................................................... 26Test 3. Trip Dropout after Reset of 87: Address 1627 .................................................................................. 28Test 4. Pickup of 87hs: Address 1604 .......................................................................................................... 29Test 5. Time Delay of 87hs Trip: Address 1626............................................................................................ 30Test 6. Trip Dropout after Reset of 87hs: Address 1627 .............................................................................. 32Test 7. Second Harmonic Restraint Per-Phase: Address 1611.................................................................... 33Test 8. Nth Harmonic Restraint Per-Phase: Addresses 1613 and 1614 ...................................................... 34Test 9. Differential Current Stopping Nth Harmonic Restraint: Address 1616.............................................. 34Test 10. Cross-Blocking, Nth Harmonic, Minimum Pickup: Address 1615 ..................................................... 34

7UT51 v3

4 PRCM-1108A-0199

Test 11. Cross-Blocking, Second Harmonic, Minimum Pickup: Address 1612................................................ 35Test 12. Cross-Blocking, Second Harmonic, Time Delay: Address 1612 ....................................................... 35Test 13. Cross-Blocking, Nth Harmonic, Time Delay: Address 1615.............................................................. 36Notes about Simulating Through-Faults and Testing the 87 Slopes................................................................ 37

Three-Winding Transformers ............................................................................................................................... 46Test 14. Through-Fault Security, Metering Validation ..................................................................................... 46Notes about Slope 1, Slope 2, and Through-Fault Restraint Area. .................................................................. 47Test 15. Slope 1 (Lower Slope): Address 1606............................................................................................... 48Test 16. Slope 2 (Upper Slope): Addresses 1607 and 1608........................................................................... 48Test 17. Minimum Current for Through-Fault Restraint Area: Address 1618................................................... 49Comments about Through-Fault Restraint Area Slope and

Maximum Duration of Through-Fault CT-SaturationRestraint: Address 1617.................................................................................................................... 50

Test 18. Status Control - Differential Elements: Discrete Inputs,Address 1601 .................................................................................................................................... 51

Thermal Overload Protection ............................................................................................................................... 53Notes about Testing 49-1 And 49-2.................................................................................................................. 53Settings for Trip Relays, Signal Relays, and LEDs – All 49 Tests ................................................................... 53Test 19. Warning, Overload Current:

Address 2405 (49-1) and 2505 (49-2)............................................................................................... 54Notes about 49 Trip Times and Alarm Times................................................................................................... 54Test 20. Warning, Temperature: Addresses 2404, 2403

and 2402 (49-1) ; Addresses 2504, 2503, and 2502 (49-2).............................................................. 55Test 21. 49 Tripping: Addresses 2402 and 2403 (49-1),

2502 and 2503 (49-2)........................................................................................................................ 56Test 22. Status Control of 49 Elements: Discrete Inputs or

Addresses 2401 and 2501 ................................................................................................................ 56External Trip Functions ........................................................................................................................................ 58

Optional Programming for All External Trip Function Tests ............................................................................. 587UT51 Test Connections for All External Trip Function Tests ......................................................................... 58Test 23. External Trips, Function Test and Trip-Time Delay:

Addresses 3002 (Trip 1) and 3102 (Trip 2)....................................................................................... 59Test 24. Status Control of External Trips: Discrete Inputs,

Address 3001 (Trip 1) and Address 3101 (Trip 2) ............................................................................ 60Test 25. Trip Dropout Time of External Trips:

Addresses 3003 (Trip 1) and 3103 (Trip 2)....................................................................................... 61Test 26. Verification of Other Discrete Input Functions................................................................................... 61

Time Overcurrent Backup Protection 50/51 And 50hs......................................................................................... 62Notes about Testing Overcurrent Protection .................................................................................................... 62Test 27. Pickup and Dropout of 50/51: Address 2112 or 2114 ....................................................................... 62Test 28. Time Delay of 51 Tripping: Address 2115 ......................................................................................... 63Test 29. Time Delay of 50 Tripping: Address 2113 ......................................................................................... 64Test 30. Manual Close Controlling 50/51 Tripping Delay: Address 2121........................................................ 65Test 31. Status Control of 50/51: Discrete Inputs or Address 2101 ................................................................ 66Test 32. Trip Dropout after Reset of 50/51: Address 2118.............................................................................. 67Notes about Testing 50hs................................................................................................................................. 68Test 33. Pickup and Dropout of 50hs: Address 2103...................................................................................... 68Test 34. Time Delay of 50hs Tripping: Address 2104 ..................................................................................... 69Test 35. Manual Close Controlling 50hs Tripping Delay: Address 2121......................................................... 71Test 36. Status Control of 50hs: Discrete Inputs or Address 2101 ................................................................. 71Test 37. Trip Dropout after Reset of 50hs: Address 2118............................................................................... 72

Tank Leakage Protection ..................................................................................................................................... 73Notes about Testing Tank Leakage Protection ................................................................................................ 73Test 38. Pickup and Dropout of Tank Leakage Protection:

Address 2703 or 2704, and Address 2709 ....................................................................................... 73Test 39. Time Delay of Tank Leakage Protection Tripping: Address 2725...................................................... 74

7UT51 v3

PRCM-1108A-0199 5

Test 40. Status Control of 64t: Discrete Inputs or Address 2701 .................................................................... 75Test 41. Trip Dropout after Reset of 64t: Address 2727.................................................................................. 76

Restricted Ground-Fault Protection...................................................................................................................... 77Notes about Testing 87n................................................................................................................................... 77Test 42. Pickup and Dropout of 87n: Address 1903......................................................................................... 77Test 43. Time Delay of 87n Tripping: Address 1925 ........................................................................................ 78Test 44. Status Control of 87n: Discrete Inputs or Address 1901 ................................................................... 79Test 45 Trip Dropout After Reset of 87n: Address 1927 ................................................................................. 79Test 46. Second Harmonic Restraint of 87n: Addresses 1910 and 1911 ....................................................... 80Test 47. Differential Current Stopping 2nd Harmonic

Restraint of 87n: Addresses 1910 and 1912..................................................................................... 81Notes about Testing the Extended Tripping

Area of 87n - Critical Angle for Restraint .......................................................................................... 82Test 48. 87n Security for External Faults and Critical Angle for

Restraint: Address 1904.................................................................................................................... 84Setting Verification after Electrical Testing........................................................................................................... 86

Control Wire, CT, and Relay Installation ....................................................................................... ...................... 87

Primary Equipment Check.................................................................................................................................... 87Electrical Drawings Wire Check ........................................................................................................................... 87CT Installation....................................................................................................................................................... 87Interposing Transformers ..................................................................................................................................... 87Relay Installation .................................................................................................................................................. 87

Commissioning Tests............................................................................................................ ................................ 89

Physical Inspection............................................................................................................................................... 89Installation Test Procedures................................................................................................................................. 89Operational Checks.............................................................................................................................................. 89Energizing the Transformer.................................................................................................................................. 90In-Service Readings ............................................................................................................................................. 90Operational Measured Values.............................................................................................................................. 90Measured Test Currents....................................................................................................................................... 90Waveform Capture during Test Fault Record – Address 4900 ............................................................................ 90Installation of 7UT51 Relay in Existing Circuit ..................................................................................................... 91Output Connections.............................................................................................................................................. 91Putting the Relay into Operation .......................................................................................................................... 92

Routine Testing of System...................................................................................................... .............................. 93

Relay Integrity....................................................................................................................................................... 93Operational Measured Values.............................................................................................................................. 93Input Integrity........................................................................................................................................................ 93Output Integrity ..................................................................................................................................................... 93Validate Metering.................................................................................................................................................. 93Measured Test Currents....................................................................................................................................... 93Waveform ............................................................................................................................................................. 94Putting the Relay into Operation .......................................................................................................................... 94

Fault Data and Analysis Tools.................................................................................................. ............................ 95

Front Panel Alarms............................................................................................................................................... 95Fault Analysis Data............................................................................................................................................... 95PC......................................................................................................................................................................... 95Saving/Archiving Fault Data ................................................................................................................................. 96Resetting/Clearing Buffers and Targets ............................................................................................................... 96

Address Index .................................................................................................................. ...................................... 97

7UT51 v3

6 PRCM-1108A-0199

Table of FiguresFigure 1: Control of a Protection Function ............................................................................................................ 10Figure 2: Discrete Signal Inputs ............................................................................................................................ 11Figure 3: Signal Contacts ...................................................................................................................................... 12Figure 4: Trip Contacts.......................................................................................................................................... 12Figure 5: LED Targets ........................................................................................................................................... 12Figure 6: Example Configuration Menu................................................................................................................. 16Figure 7: Matching/Adaptation Factor Relay Front Display................................................................................... 17Figure 8: Measured Current Tests ........................................................................................................................ 19Figure 9: Operational Annunciations and Fault Log.............................................................................................. 19Figure 10: Waveform Capture Example.................................................................................................................. 21Figure 11: Test 1 Connection Diagram ................................................................................................................... 26Figure 12: Test 2 Connection Diagram ................................................................................................................... 27Figure 13: Test 3 Connection Diagram ................................................................................................................... 28Figure 14: Connection Diagram .............................................................................................................................. 29Figure 15: Test 5 Connection Diagram ................................................................................................................... 30Figure 16: Test 6 Connection Diagram ................................................................................................................... 32Figure 17: Test 7 Connection Diagram ................................................................................................................... 33Figure 18: Test 10 Connection Diagram ................................................................................................................. 34Figure 19: Test 12 Connection Diagram ................................................................................................................. 35Figure 20: Dy1 Transformer, ................................................................................................................................... 38Figure 21: Test Connections for Dy1 Transformer with a-Phase-Ground Through-Fault...................................... 39Figure 22: Test Connections for Yd11 transformer with a-Phase-Ground Through-Fault, Io-Elimination .............. 42Figure 23: Yd11 Transformer a-Phase-Ground Fault .............................................................................................. 44Figure 24: Test Connect for a Yd11 Transformer, with

an a-Phase-Ground Through-Fault, Io-Correction................................................................................. 45Figure 25: Differential Characteristics ..................................................................................................................... 47Figure 26: Test Connections for Testing 49-1 and 49-2.......................................................................................... 53Figure 27: Tests 23-25 Connection Diagram .......................................................................................................... 58Figure 28: Test 27 Connection Diagram ................................................................................................................. 62Figure 29: Test 28 Connection Diagram ................................................................................................................. 63Figure 30: Test 29 Connections Diagram ............................................................................................................... 64Figure 31: Test 32 Connection Diagram ................................................................................................................. 67Figure 32: Test 33 Connection Diagram ................................................................................................................. 68Figure 33: Test 34 Connection Diagram ................................................................................................................. 69Figure 34: Test 37 Connection Diagram ................................................................................................................. 72Figure 35: Test 38 Connection Diagram ................................................................................................................. 73Figure 36: Test 39 Connection Diagram ................................................................................................................. 74Figure 37: Test 41 Connection Diagram ................................................................................................................. 76Figure 38: Test 42 Connection Diagram ................................................................................................................. 77Figure 39: Test 46 Connection Diagram ................................................................................................................. 80Figure 40: Test 47 Connection Diagram ................................................................................................................. 81Figure 41: Test 48 Connection Diagram ................................................................................................................. 84Figure 42: Two-Winding, Delta-Wye Transformer................................................................................................... 88Figure 43: Three Winding, Delta-Wye-Delta Transformer ....................................................................................... 88Figure 44: WinDIGSI Metering Data Screen........................................................................................................... 90Figure 45: Waveform Capture of Normal Line Current ........................................................................................... 91Figure 46: Example of Fault Data............................................................................................................................ 95

7UT51 v3

PRCM-1108A-0199 7

Table of Tables

Table 1: Measured Values..................................................................................................................................... 20Table 2: Currents Limitations................................................................................................................................. 23Table 3: Default Settings for Some of the Signal Relays:...................................................................................... 24Table 4: Default Settings for Some of the LEDs:................................................................................................... 25Table 5: Default Settings for the LCD after a Fault................................................................................................ 25Table 6: Correction Factor for 87-Itrip(Wx)............................................................................................................ 25Table 7: Source 1 Current- Connections, Delta-Grounded

Wye Transformers (Dyz).......................................................................................................................... 39Table 8: Equations of Winding 2 Currents for IREST and IDIFF,

and Relationship of Restraint Currents for Phase-Ground, Through-Faults. .......................................... 40Table 9: Source 2 Current- Connections, Delta-Grounded Wye Transformers (Ydz)........................................... 42Table 10: Equations of Winding 2 Currents for IREST and IDIFF, and

Relationship of Restraint Currents for Phase-Ground, Through-Faults. ................................................. 43Table 11: Maximum Θ for 87N Tripping with

3I0* = 3I0** = [2 X Address 1903 X INRGFWx or IOBJRGF] and k-Values for Address 1904 ..................................................................................................................... 84

Table 12: Maximum Θ for 87N Tripping with 3I0* = 3I0** = [3 X Address 1903 X INRGFWx or IOBJRGF] and k-Values for Address 1904 ..................................................................................................................... 84

7UT51 v3

8 PRCM-1108A-0199

IntroductionThis manual is to be used in conjunction with theSiemens 7UT51 v3 Protective Relay InstructionManual. Prior to working with this relay, it isrecommended that the instruction manual be readand understood. The relay has many powerfulfeatures that should be understood before anysettings are applied, tests performed, or installationmade.

This handbook describes manual acceptancetesting, installation, commissioning, andmaintenance of a Siemens 7UT513 V3 Protective

Relay in a transformer differential scheme. Theprocedures take into account that the protectionsettings may vary, but assumes that the relay’scontact inputs, contact outputs, and LEDs areconfigured with their default values (unless statedotherwise). It is recommended that the actualsettings be applied to the relay prior to installationtesting. Actual test values for a specific applicationmust be calculated from the application’s data. Seethe Siemens 7UT51 Instruction Manual for defaultsettings of each function.

Definition of Terms

Adaptation Factor See Matching Factors

CT Current Transformer

CTR Current Transformer Turns Ratio

Cross-Block Harmonic blocking across phases

Discrete Input Binary Input

Enabled/Disabled (on relay LCD) orNonexistent/Existent (in WinDIGSI and theSiemens 7UT51 Instruction Manual )-The available protective and additional functions canbe programmed Enabled/Existent or Disabled/Nonexistent . Functions which are configuredDisabled will not be processed. There will be noannunciations and the associated setting parameterwill not be requested during setting.

Password� A password is required to change any settings,

or to run any test routines.� A password is not required to view annunciation

logs, measured values, or settings.� The password is six zeroes: 000000.

In or I N Nominal rated current of the monitoredwinding or side of the transformer.

INsecWx Rated secondary current of winding x.

IObjsec Rated secondary current of the virtual object.

IxLy Winding x, Phase y.

Marshalling A special-use term that refers to theprogramming assignment of a set of logical functionsto various physical I/O devices.

Matching Factors Based on the transformer settinginformation entered into Address Block 1100, therelay will match the currents to be process by therelay. The relay matches these currentsmathematically for any chosen vector group (seeVector Group Chart in the Siemens 7UT51Instruction Manual) using the equation:

[I*] = k x [K] x [I]where:

[I] = matrix of measured currents IA, IB, IC[I*] = matrix of matched currents IA*, IB*, IC*k = current matching scalar factor (see note below):

kCT1 = current processed by 7UT51 current through the relay terminals

[K] = current matching coefficient matrix (See VectorGroup Chart in the Siemens 7UT51 InstructionManual.)

Note: The k matching factors are calculated by therelay from the entered rated data and can beread out in the operational annunciation inAddress Block 5100.

Megger A high-range ohmmeter having a built-in,hand-driven generator as a direct voltage source,used for measuring insulation resistance values andother high resistances. Also used for continuity,ground, and short circuit testing in general electricalpower work.

NV-RAM Non-volatile random access memory.

Parameterizing Setting up/programming theparameters of the relay.

RGF Restricted ground fault protection.

7UT51 v3

PRCM-1108A-0199 9

Star-point The common point or the non-polarityconnection of a Y connected transformer.

SWITCH-OFF The switch-off of a function meansthat the protective function has been established asEnabled ; however, the function is turned Off .

VA Rated Apparent Power

Vn/VN Rated phase to phase voltage or if thetransformer is a LTC,Vn = (2 X Vmax X Vmin) / (Vmax + Vmin)

Vector Group Integer n that represents the phaseshift from the first winding to the second winding of apower transformer, n x 30°. See the Siemens7UT51 Instruction Manual for list of vector groups.

WinDIGSI Windows-based, Siemens software thatwill enable the user to perform all settings and data

requisition with a PC through the relay’scommunication port. At the computer, the data canbe easily read on the screen, changed, saved todisk, or printed.WinDIGRA A full-function digital oscillographicanalysis (Windows-based) software that will allowthe user to view captured waveforms.

Winding In this document it will refer to the side ofthe transformer or tertiary. Winding 1 is defined asthe reference winding. The reference winding isnormally that of the higher voltage; however, if a CTis installed in the ground lead of a grounded wyeconnected transformer, that winding must be usedas the reference winding in order to ensureincreased ground fault sensitivity by correction ofthe zero sequence current.

7UT51 v3

10 PRCM-1108A-0199

Understanding the Siemens 7UT51Numerical Protective Relay

The following diagrams are intended to furtherenhance the understanding of the Siemens 7UT51by giving a visual representation of the relayfunctions. It is also important to understand these

protective functions and how the relay must beprogrammed to properly operate with the connectedsystem.

Figure 1: Control of a Protection Function

Control of a Protection Function

⇒ The protective function must first be set as Enabled .⇒ Once made Enabled , the protective function can be turned Off

or On via the relay front panel, remote interface, PC, or discreteinput.

⇒ If the protective function is Enabled and On, the trip functioncan be blocked; however the relay will still function normally andrecord events accordingly.

PCDisplaySCAD

ProtectionFunction

ENABLED /DISABLED

OnOff

B11

B12B13t

Blockt

7UT51 v3

PRCM-1108A-0199 11

Figure 2: Discrete Signal Inputs

SignalCircuit

InternalEvent(s)

Event 1Event 2::Event 10

INPUT

Go LO to HIwhen rise above19V

Discrete-SignalInputsEach discrete-signalinput is actuated byvoltage in a signal-circuit. Each inputcontrols up to 20events. Each event isconfigured to occureither when thediscrete input isactuated (HI), orwhen it ceases to beactuated (LO).

Go LO to HI whenrise above 65V

7UT51 v3

12 PRCM-1108A-0199

Figure 3: Signal Contacts

Figure 4: Trip Contacts

Figure 5: LED Targets

Signal Contacts

This diagram illustratesthe functions of thesignal contacts. Eachsignal contact iscontrolled by up to 20events and is used tosound alarms foroperators or to signalother protectiondevices.

Event 1Event 2

::

Event 20

Trip Contacts

Each signal contact iscontrolled by up to 20events and is used totrip circuit breakers.

Event 1Event 2

::

Event 20

LED Targets

This diagram illustrates thelogical process of thisfunction. Each LED can becontrolled by up to 20events. Each event caneither latch (memorized), ornot latch (not memorized)an LED. Latched LEDs canbe reset using a key on thefront panel, a discrete-signalinput, or an attached PCrunning WinDIGSI.

Event 1Event 2

::

Event 20

7UT51 v3

PRCM-1108A-0199 13

Suggested Test EquipmentThe following equipment is suggested to perform theacceptance and commissioning tests for thetransformer differential scheme. Further detail on theequipment specifications required for acceptancetesting is given in the Acceptance Testing section ofthis document.

• One control power source DC and AC.

• One phase angle meter.

• One megger – up to 500V.

• Two accurate variable single-phase currentsources, one of which can output 300Hz current.

• One push-button (or other mechanical) switch toapply voltage to contact inputs during testing ofrelated functions.

• One sensor for detecting closure of outputcontacts, for example an ohmmeter, a bulb with apower supply, or buzzer with a power supply.

• One timer that is started by the test set output andstopped by the relay output contact.

• One high impedance – low range volt/ohm meter.• Two ammeters.• Load box.• One 1:2 isolation power transformer may be

required for testing of the control circuitry.• Telephone set for talking circuits with remote

terminations may be required for testing of thecontrol circuitry.

7UT51 v3

14 PRCM-1108A-0199

Siemens 7UT51 Relay Pre-EnergizationChecklist

• Before energizing the relay, it must be installedfor at least two hours to ensure temperatureequalization and to avoid condensation.

• Switch off the DC supply and the potentialtransformer circuit.

• Verify that the miniature slide switch on the frontpanel is in the Off position.

• Fit a DC ammeter in series with the auxiliarypower circuit using a range of 1.5 to 3 amperes.

• Close the DC supply circuit breaker; checkpolarity and magnitude of voltage at theterminals of the unit or at the connector module.

• Steady-state current consumption should beinsignificant. Any initial transient current is dueto charging of the storage capacitors.

• Slide the switch on the front panel to the Onposition. On completion of the startup/ warmupperiod, the green LED on the front comes on in0.5 seconds and the red LED goes off after 5seconds.

• Open the DC power supply circuit breaker.

• Remove DC ammeter; reconnect the auxiliaryvoltage leads.

• Check the direction of phase rotation at the relayterminals (clockwise).

• Ensure that trip circuits are disconnected fromthe relay trip contacts and are left open-circuited. Also, disconnect from externalbreaker failure devices any of the relay outputsthat are being tested.

• Ensure that the current circuits are disconnectedfrom the relay current inputs and are short-circuited.

• Ensure that contact inputs to be tested aredisconnected from all circuits.

Hazardous voltage or current.

Can cause death, serious personalinjury, or property damage.

Only qualified personnel should test orcommission a really. Read andunderstand this manual, the Siemens7UT51 v3 Protective Relay InstructionManual, and the manuals for any testequipment before proceeding.

Before performing work on currenttransformer wiring, always short circuit thesecondary of all the current transformers.

To avoid damage to the relay, ensure thatoutput contacts do not break currentsgreater than their ratings.

To avoid damage to the relay, ensure thatany control power or test value applied tothe relay does not exceed thecorresponding input’s limit.

7UT51 v3

PRCM-1108A-0199 15

Setting and Programming the Siemens 7UT51 Relay

Have the Relay Setting Sheets (included in theSiemens 7UT51 Relay Instruction Manual)completely filled out with the required settings.

If the meaning of the required parameter is not clear,it is usually best to leave it at the factory setting.

Front Panel

(See Relay Front Panel View in the Siemens 7UT51Instruction Manual.)If the parameter address is known, then directaddressing is possible on the front panel of relay.This is achieved by depressing the Direct Accesskey, followed by the four-digit address, and thenpressing the Enter key.

If the parameter address is not known, paging bymeans of the arrow keys on the front panel of therelay is possible.

To change the content of a memory address, theaddress must be selected and the relay must beplaced in Password mode.

The relay will remain in password mode until yousave the settings.

Note : You may be required to save a settingchange before the relay will allow you toprogram parameters related to that setting.This will also required a re-entry of thepassword.

If you are changing a selection from a list, press Nountil the option you want is displayed, then pressYes.

If you are changing an entered value, after enteringthe appropriate address, enter the new value, thenpress the Enter key.

The setting procedure can be ended at any time bythe key combination of F and Enter .

PC

The programming of the relay with a PC andWinDIGSI software is straight forward since it isWindows based; however, consult the SiemensWinDIGSI User’s Manual for detailed instructions ifnecessary.

When using the PC to set the parameters, it is bestto enter the data as you scroll through the screensrather than programming for particular functions.The following parameters must be entered to enablethe relay to respond accurately (with the desiredalarms, measurements, and event information) in an87-transformer differential scheme:

Configuration Menu(See Figure 6)

7100 Local User Interface7200 Configuration of Comm Port7400 Waveform Capture7800 Device Options

Marshalling Menu

6100 Configuration of Discrete Inputs6200 Configuration of Signal Relays6300 Configuration of LED Indicators6400 Configuration of Trip Contacts

Settings Menu

1100 Transformer Data (see Important Notesbelow)

1400 Data Associated with a User-DefinedMachine

1600 87–Transformer Diff Protection Data2900 Measured Value Supervision

Additional Protective Functions

The following address blocks must be entered to setup other available or optional protective functions:

Restricted Ground-Fault ProtectionAddress Block 1900 for 87N

The relay must first be Enabled in the DeviceOptions menu, Address 7819 Restricted Ground-Fault Protection. Settings can then be made for thisprotective function in the Settings menu, AddressBlock 1900.

7UT51 v3

16 PRCM-1108A-0199

Figure 6: Example Configuration Menu

Backup Overcurrent Time FunctionAddress Block 2100 For 50/51

The relay must first be Enabled in the DeviceOptions menu, Address 7821 Backup OvercurrentProtection. Settings can then be made for thisprotective function in the Settings menu, AddressBlock 2100.

Thermal Overload Protection 1 and 2Address Blocks 2400 and 2500

The relay must first be Enabled in Device Optionsmenu, Address 7824 and 7825 Thermal OverloadProtection. Settings can then be made for thisprotective function in the Settings menu, AddressBlock 2400 and 2500.

Transformer Tank ProtectionAddress Block 2700

The relay must first be Enabled in Device Optionsmenu, Address 7827 Transformer Tank Protection.Settings can then be made for this protectivefunction in the Settings menu, Address Block 2700.

External Trip FunctionsAddress Block 3000 and 3100

The relay must first be Enabled in Device Optionsmenu, Address 7830 and 7831 State of External TripFunctions. Settings can then be made for thisprotective function in the Settings menu, AddressBlock 3000 and 3100.

Important Notes about Transformers

Regulated Transformer

If a transformer winding is regulated, then the actualrated voltage of the winding is not used as Vn. Theaverage current of the regulated range should beused.

Vn=2 x (Vmax x Vmin)(Vmax + Vmin)

FOA Transformers

If the transformer is rated as FOA, it isrecommended that the minimum MVA rating be usedfor VA (the Rated Apparent Power); however, thereis a possibility that the relay will be picked up all thetime when the transformer is at or near full-load FOArating.

7UT51 v3

PRCM-1108A-0199 17

Accessing Data

The Siemens 7UT51 relay is microprocessorcontrolled, it can monitor, record, and store inputand output data. This data is available through theLEDs and LCD display on the relay and can also beaccessed via a PC with WinDIGSI software or aSCADA system. Using the WinDIGSI software, thecurrents can be monitored, event logs can be read,tested performed, and the oscillograms can beviewed for fault analysis.

Matching or Adaptation Factors

To check that the matching factors for the ratedcurrents of the protected object are correct:

• From the front panel of the relay, these factorsare available in Address 5100 and updated eachtime the parameterizing process has beenterminated.

• Using the WinDIGSI software, these values arefound in the Operational Annunciations listed asAdaptation Factors (Figure 7).

Use the calculated factor in the following equation:

k CT Wx = Current processed by 7UT51Current through the relay terminals

KsCTWx are the factors for inputs from the CT inthe ground of a star-point connection (common pointof a wye transformer).

Figure 7: Matching/Adaptation Factor

Relay Front Display

Address Block 7100 contains addresses that specifythe appearance and content of the LCD display onthe front panel of the relay and the type of event thatwill update the LCD display and LED states.

Address 7105 and 7106 control lines 1 and 2 of theLCD during normal operation. Address 7107 and7108 control line 1 and 2 of the LCD after a networkdisturbance.

Address 7110 determines the type of event that willupdate the LCD information and LED states.

Measured Current TestsAddress Block 4100

The relay measurement of all currents and phaseangles can be read through test Address Block4100:

• 4101 Line Currents• 4121 Line Phase Angle Relations• 4141 Star Point Phase Angles• 4161 Differential and Stabilizing Currents

The test can be initiated directly from the relay panelor via WinDIGSI. To initiate this test with WinDIGSIgo to the Test menu, choose Commissioning Test ,and then choose any of the four measurementslisted above. See Figure 8 for WinDIGSI screenexample.

After start, the relay first checks whether themeasurement can be carried out. If a protectionfunction has picked up before, the measurement isrejected. When the measured quantities are toosmall, a corresponding message **** is given.

Note: If an invalid or Current Too Small messageis given on one side or phase, furthercurrents can still be read.

It is important to that the current, differential andstabilizing values are referred to the rated current ofthe transformer winding. See Figure 8 for DIGRA ascreen example.

7UT51 v3

18 PRCM-1108A-0199

Line Phase Angle Relations(Figure 8)

The phase angle relations are displayed in Address4121 after the test has been performed. SymbolsW1, W2, W3*, WA*, WB* for the winding of thetransformer on the relay LCD (such as I1, I2, I3 inWinDIGSI). Symbols Ia, Ib, and Ic for the phase onthe relay LCD (PhA, PhB, and PhC in WinDIGSI).

The phase angle differences are displayed in 30°increments; small deviations up to ±10° aretolerated. When the measured angle is outside ofthis tolerance range, the display shows inval . Theangle differences are defined for clockwise phaserotation. The angle differences of the three currentsof side 1, 2, and 3 should be as follows:

• W1Ib – W1Ia = 240°, W2Ib – W2Ia = 240°, W3Ib– W3Ia = 240°

• W1Ic – W1Ia = 120°, W2Ic – W2Ia = 120°, W3Ic– W3Ia = 120°

The polarities of the through flowing currents aredefined to be equal, as when currents of equalphase flow through the protected object, the angledifference is 0, provided the connections are correct.But the theoretical angle value depends on thetransformer and the vector connection group. Themeasured angles must be equal for all three phases.If not, individual phases will be interchanged.

The polarity of the current connections and theparameterized polarity are taken into considerationwhen the angles are displayed. Therefore, if allthree angles differ by 180° from the theoreticalvalue, the polarity of one complete CT set is wrong.This can be corrected by checking and changing thecorresponding plant parameters:

• Address 1105 for the primary winding of thetransformer

• Address 1125 for the secondary winding of atransformer

The connection group values of power transformersare defined from the higher voltage side to the lowervoltage side. When measuring from the lowervoltage side: 360° minus the stated angle is valid.

Zero Sequence Test(Figure 8)

Address 4141 checks the angle measurement of thestar-point to the line currents. Numerical values areto be expected only for those current inputs whichare included in the test current path, for theremaining currents, **** is displayed.

Note: If an additional current input is not assignedto any side of the protected object(Addresses 7806 and 7807), the associatedmeasured values will not appear.

Differential and Stabilizing Current Check(Figure 8)

Address 4161 checks the differential and stabilizingcurrents. Go to Address 4161 and read thecalculated values by scrolling through the display.

If checking line current or through-faults, thedifferential value should be negligible against themagnitude of the line currents. The stabilizing(restraint) value should be approximately twice theline or test current value. Important to note that thedifferential and stabilizing values are referred to asthe rated current of the transformer winding.

If considerable differential currents occur, recheckthe following parameters:

• Check Addresses 1102 to 1104, matching ofTransformer Winding 1

• Check Addresses 1121 to 1124, matching oftransformer winding.

Restricted Ground-Fault Current Test

If the relay is equipped with the restricted groundfault protection and this is to be used, a further zerosequence current test must be carried out.

Address 4181 will test and display themeasurements for the restricted earth faultprotection.

Leaving Test OperationAddress Block 4800

When the relay is in test mode, the differentialprotection and the restricted ground fault protectionare not effective, even when they are switched On.If no activities are carried out within 60 minutes, therelay automatically terminates the test operation. Allprotection functions that are switched On are thenoperational again. It is recommended that the Test

7UT51 v3

PRCM-1108A-0199 19

mode be definitely finished once the tests have beencompleted.• Access Address 4800 Commission Test Stop.• Page to Address 4801 Test Stop?• Enter Yes key.

Figure 8: Measured Current Tests

Operational Annunciations (Event Log) AddressBlock 5100

The operational annunciations can store the last 50operational events along with the time and date ofeach annunciation. The data can be accessed viathe front panel or one of the data ports.

Network-Disturbance Annunciations (Fault Logs)Address Blocks 5200, 5300, 5400

Each Fault Log records the first 80 events after apickup, each date and time stamped. The relayholds 3 fault logs. If necessary, the oldest one isoverwritten when a new one opens; however, theycan be saved to a PC.

Figure 9: Operational Annunciations andFault Log

7UT51 v3

20 PRCM-1108A-0199

Operational Measured ValuesAddress Block 5700

Measured values are system data collected andcalculated by the relay. The relay can displaymeasured values on the front panel LCD, or exportthem to a PC. The display of measured values isupdated every 1 to 5 seconds.

Address Block 5700 will display winding current as apercentage of the rated current and winding currentin amps. See Figure 10 for a list of all operationalmeasured values.

Address Block 5900 will display Temperature rise ofeach thermal overload function (49-1 and 49-2)separately for each phase, or for all three phasescombined.

Table 1 : Measured Values

LCD Address DescriptionW1 Ia(%)W1 Ib(%)W1 Ic(%)

570157025703

Current in winding or side 1 forphases A, B, and C as apercentage of the ratedcurrent.

W2 Ia(%)W2 Ib(%)W2 Ic(%)

570457055706


W3 Ia(%)W3 Ib(%)W3 Ic(%)

570757085709


IA(%)IB(%)

57105711

Additional current inputs whenused and assigned as apercentage of the ratedcurrent. (7UT513 only)

W1 IaW1 IbW1 Ic

572157225723

Current in winding or side 1 forphases A, B, and C in amps

W2 IaW2 IbW2 Ic

572457255726

Current in winding or side 2 forphases A, B, and C in amps

W3 IaW3 IbW3 Ic

572757285729

Current in winding or side 3 forphases A, B, and C in amps(7UT513 only)

IAIB

57305731

Additional current inputs whenused and assigned in amp ormilliamps.(7UT513)

θ1/θtrpθ1/θtrpAθ1/θtrpBθ1/θtrpC

5911591259135914

Temperature rise of 49-1protection function for allphases, and separately forphases A, B, and C.

θ2/θtrpθ2/θtrpAθ2/θtrpBθ2/θtrpC

5921592259235924

Temperature rise of 49-2protection function for allphases, and separately forphases A, B, and C.

7UT51 v3

PRCM-1108A-0199 21

Waveform Data

The relay can simultaneously capture data for allcurrent inputs and up to four user-defined functionsthat report the status of discrete-signal inputs. Thedata must be downloaded to a PC for analysis andstorage.

The data storage parameters can be programmed inAddress Block 7400. Data storage can also beinitiated via a discrete input or by the operator via thefront panel of the relay or a PC. The configurationparameters required for this function to operate areas follows:

• Address 7402 initiates the waveform capturewith pickup or trip.

• Address 7410 determines the maximum lengthof time for the waveform capture.

• Address 7411 sets the pre-trigger time.

• Address 7412 sets amount of capturedwaveform after trigger.

• Address 7431 Storage time for triggering viadiscrete (binary) input.

• Address 7432 Storage time for triggering via thekeyboard.

Manual starting of the record can be carried out inAddress Block 4900. The message will read: FaultRec. Start? Confirm with Yes key. The relay willacknowledge successful completion of the testrecording.

To initiate manual starting of a fault via WinDIGSI:• Go to the Options menu.

• Choose Device.

• Choose Initiate Fault Record.

To access the waveform data using WinDIGSI andDIGRA, choose the following menu items:

Fault

Fault record…Select fault instance

Options DIGRAType of Graph (Prim., Sec., orNormalized)

DisplayAnalog Curves

From this point several choices aregiven to display and analyze the data.

Figure 10: Waveform Capture Example

7UT51 v3

22 PRCM-1108A-0199

Acceptance Testing

7UT51 Electrical Testing

The purpose of this section is to provide a procedurefor acceptance testing and installation testing a7UT51. The procedure is for manual testing,although the document could be used as afoundation for automated test plans. Simpleadaptations allow the procedure to also be used fortesting after an in-service setting change. Theprocedure can be easily adapted for evaluation andfamiliarization with a 7UT51.

For this document, acceptance testing is testing auser performs to become satisfied that a 7UT51 isfunctioning properly. Installation testing is done by auser to verify that the 7UT51 will perform correctlywithin a specific application. For many users,acceptance testing and installation testing are thesame.

It is important to note that routine testing is coveredin another section.

The degree of testing needed for acceptance testingand installation testing is dependent upon the user’sphilosophies. There is sufficient detail to guide theuser in adapting the procedure to the user’ssatisfaction.

Acceptance Testing

A 7UT51 has many protective elements and controlfeatures that can be used in a variety of ways.Testing all of the elements and control features, inthe many different ways they can be used, is notrecommended. Such testing would be very time-consuming. Instead, the procedure should be usedwith typical settings and control, or settings andcontrol that are likely to be used. Then only theapplicable tests need to be performed. Using thedefault settings and control is a good alternative.

Installation Testing

Perform only the tests required to check the settingsand control to be used in the specific fieldapplication. Complete testing of the discrete inputs,signal contacts, and trip contacts is recommendedusing this procedure. This will reduce field

operational-checking of the transformer protection tosimply checking the CT connections, 7UT51 inputconnections, and wiring of the output contacts.

For a 7UT51 with multiple sets of protection settingsbeing used, fully test one set, and only the changesin the remaining sets.

Testing for In-Service Setting Changes

Perform only the tests in the procedure that areapplicable to the change.

Evaluation Testing

While the procedure is specifically written foracceptance and installation testing, the procedurecan easily be adapted to allow the user to performexhaustive evaluation tests. In the process, the userwill become very familiar with the 7UT51.

Perform all of the electrical tests, ignoring anyinstructions to skip a particular test. Repeat eachtest, trying different values for the setting beingchecked. Test different programming of the inputsand outputs.

Automated Testing

The procedure provides the groundwork forautomated test plans of a 7UT51. The user cancreate the plans with the test equipment of choice.

Acceptance Test Equipment

The procedure requires the following test equipment:• Power source matching the rating of the 7UT51• Two variable current sources with the following

capabilities:⇒ Accuracy of +/- 2% or better over the entire

output range⇒ One source that can provide 20 amps (if

7UT51 rated for 5 amps)⇒ One source that can provide 120 Hz, 180

Hz, 240 Hz, and 300 Hz current⇒ Both sources can be individually or

simultaneously turned On and Off.• A timer that can be started when either a current

source is turned On or Off , and stopped byeither the opening or closing of a dry contact.The accuracy should be +/- 2% or better. Atimer built-in to a test-set with one (or both) ofthe current sources is preferred.

• An ohmmeter, or other sensor for detecting atransition of a dry contact

7UT51 v3

PRCM-1108A-0199 23

• An On/Off switch to apply DC voltage to discreteinputs of the 7UT51.

• Calculator with the capability of performing sine,cosine, and natural log functions.

The following is not required, but highlyrecommended:• A timer with +/- 2% accuracy or better, that can

be started by the opening or closing of a drycontact, and stopped by the opening or closingof a dry contact.

• Computer with WinDIGSI software and cable.

Important Notes about the Procedure

1. Do not exceed the current limitations of the7UT51.The current limitations (rms) of the CT inputsassociated with the transformer winding andneutral CTs are:

Table 2: Current Limitations

7UT51Rated

Current

ContinuousCurrentRating

10-SecondCurrent Rating

5 AMPS I ≤ 20 AMPS 20AMPS < I ≤ 100AMPS

1 AMP I ≤ 4 AMPS 4 AMPS < I ≤ 20AMPS

The rated current is on the nameplate.

Be especially mindful of the current limitationswhen testing the high-set differential element, theupper slope of the differential characteristic, therequired restraint current to activate the through-fault-CT-saturation restraint, the high-set elementof the overcurrent backup protection, and thethermal overload elements.

The current limitations for the CT inputassociated with the highly sensitive tank leakageprotection, terminals [1D1-1D2] are:

• Continuous Current Rating:I ≤ 15 Amps

• 10 Second Current Rating:15 Amps < I ≤ 100 Amps

2. Calculate the rated currents of transformerwindings and the virtual object.

The rated currents are needed throughout theprocedure. The rated currents should becalculated and recorded before the procedure isstarted. With INsecWx being the rated current ofWinding “x” (x = 1, 2, or 3) and IObjsec being therated current of the virtual object, both in CTsecondary terms:

INsecWx =(Winding Rating in kVA)

(1.732)x (Winding kV θ-θ)x(Winding CTR)

The values to use for this equation are found inAddress Block 1100. Be aware that CT ratiosare not entered in this Address Block if theCTs have a secondary rating of 5 amps. Instead,the primary current ratings of the CTs, for the setratios, are entered in Addresses 1104, 1124, and1144. For CTs with a rating of 5 amps, theseaddresses must be divided by 5 amps to obtainthe ratios to use in the above equation.

IObjsec =Address1401 x (CT Sec. Rating in amps)Address 1402

The CT secondary rating is either 5 amps or 1amp.

3. Test equipment accuracy.

Unless otherwise stated, +/- 2% accuracy isassumed for the test equipment. This accuracy isincluded in the values given in the ExpectedResults part of the procedure.

4. Check titles for settings and events.

Event titles and setting options for the addressesmentioned in the procedure are as they appear inthe WinDIGSI software, Version 3.22. The titlescan vary between the software and the frontpanel of the 7UT51.

5. Verify actual programming of trip relays andsignal relays.

The Expected Results part of most tests in theprocedure has the operation of the trip relays,signal relays, LEDs, and LCD that should occur forthe test, based on the default settings of theseoutputs and targets. For each test, the usershould always verify the operation of the relaysand targets based on the settings for the particular7UT51 being tested.

7UT51 v3

24 PRCM-1108A-0199

Verification of the programming of trip relays andsignals relays is especially important duringinstallation testing. The user may have to addtests to the procedure to verify each output relay isoperating as intended.

The relay and target default settings of interest inthis procedure are given below. They apply for a7UT513. The programming also applies to a7UT512 except this protective system has triprelays 1 and 2, signal relays 1-4, and LEDs 1-6.

Default settings for Trip Relay 1 through TripRelay 5 (addresses 6401 through 6405) are:

5691 87-Diff protection: Trip5921 Transformer tank prot.: General Trip5692 87HS-Diff protection: Trip1571 49-TRIP by thermal O/L protection 12451 BU Overcurrent+G/F : General Trip1621 49-TRIP by thermal O/L protection 25821 Restricted ground fault: General Trip

6. Be aware of control of protective elements bydiscrete inputs.

The operational status of most of the protectiveelements can be controlled by discrete inputs.Before testing any element, determine if any suchcontrol is intended, and apply (or remove) thenecessary input to allow testing. Tests areincluded to verify the control with the input in theopposite state as that needed for testing.

Table 3: Default Settings for Some of theSignal Relays:

AddressSignalRelay

Default Programming(Events)

6201 1 0511 General trip of therelay

6202 2 5671 87-Diff protection:General trip

6203 3 2451 BUOvercurrent+G/F :General Trip

6206 6 1571 49-TRIP bythermal O/L protection 11621 49-TRIP bythermal O/L protection 2

6207 7 1566 49-Thermal O/Lprot. 1: Thermal warning1616 49-Thermal O/Lprot. 2: Thermal warning

6208 8 5821 Restricted groundfault: General TRIP

6209 9 5921 Transformer tankprot.: General TRIP

6210 10 0391 Warning stagefrom Buchholzprotection

6211 11 0392 Tripping stagefrom Buchholzprotection

7UT51 v3

PRCM-1108A-0199 25

Table 4: Default Settings for Someof the LEDs:

Address LEDDefault Programming(Events)

6301 1 0511 General trip of theRelay m

6302 2 5691 87-Diff protection:Trip m

6303 3 5692 87HS-Diff protection:Trip m

6304 4 2451 BU Overcurrent+G/F: General Trip m

6307 7 5821 Restricted ground-fault: General TRIP m

6308 8 5921 Transformer tankprot.: General TRIP m

6309 9 1571 49-TRIP by thermalO/L protection 1 m

6310 10 1621 49-TRIP by thermalO/L protection 2 m

6311 11 0391 >Warning stage fromBuchholz prot. m

6312 12 0392 >Tripping stage fromBuchholz prot. m

Table 5: Default Settings for the LCDafter a Fault

AddressLCDLine Default Programming

7107 Top 0543 Protectionfunction(s) pickup

7108 Bottom 0544 Protective Trip

Transformer Differential Protection

Differential protection is existent and operationalwhen Address 7816 = Existent and Address 1601 =On.

Table 6: Correction Factor for 87-I trip (Wx)

Type of Fault

Winding 1(A,B,C)

ReferenceWinding

Winding 2(a,b,c) orWinding 3(a’,b’,c’)

Even NumberVector Group

1

Winding 2(a,b,c) orWinding 3(a’,b’,c’)Odd NumberVector Group 1

3-Phase 1.0 1.0 1.02-Phase 1.0 1.0 0.8661-Phasewith I 0 –Elimination 2

1.5 1.5 1.732

1-Phasewithout I 0 –Elimination 3

1.0 1.0 1.732

Notes :

1. Vector Group settings are Address 1121 forWinding 2, and Address 1141 for Winding 3.For this table, 0 is considered even.

2. Use this row if the I0Process setting for thetested winding is I0 – Elimination. The settingsare Address 1106 for Winding 1, Address 1126for Winding 2, and Address 1146 for Winding 3.

3. Use this row if the I0Process setting for thetested winding is either Without orI0 – CORRECTION. The settings are Address1106 for Winding 1, Address 1126 for Winding 2,and Address 1146 for Winding 3.

In tests 1-3 current is injected in one phase at anytime; therefore, use the rows for 1-phase faults. Theother fault types are given if the user wishes toexpand the tests.

7UT51 v3

26 PRCM-1108A-0199

Test 1. Minimum Pickup of 87: Address 1603

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’

Test Equipment 7UT51 Relay

I1ContactMonitor

TripContact 1

W1

W2

W3(7UT513only)

Figure 11: Test 1 Connection Diagram

Connect the 7UT51 as shown in Figure 11.

1. Program Trip Relay 1 to include 5691 87-Diffprotection: Trip. (The default setting issufficient.)

2. Slowly increase the current from 0 A until TripContact 1 closes. Record the pickup current atcontact closure. Check the state of the other tripcontacts, the signal contacts, and the LEDs.

3. Slowly reduce the current until the contact dropsout. Record the current at dropout. Check thestates of the other contacts and LEDs. Note theLCD indications.

4. Turn Off the current and reset the LEDs andLCD.

5. Performing tests on one phase at a time, repeatsteps 1-4 for the remaining phases of Winding 1,and the three phases of Winding 2 and Winding3 (if applicable).

Expected Results :

Pickup Current and Dropout Current

For each phase of each winding, the pickup currentat contact closure should be within +/- 5% of 87-Itrip(Wx).

The dropout current at contact opening, of anywinding phase, should be between 61.5% and78.5% of the pickup current for that phase.

Contacts, LEDs and LCD

The expected operations of the trip contacts, signalcontacts, LEDs, and LCD depend on theprogramming of the 7UT51. The user should checkfor correct operations of these outputs.

For the default settings, all trip contacts shouldclose, signal relays 1 and 2 should operate, andLEDs 1 and 2 should light when 87 trips. At dropout,the contacts should reset but the LEDs shouldremain lit because they are set to latch. When thecurrent is turned off, the LCD should display 87DiffGenFlt and 87DiffGenTrip .

Remaining Tests of the Differential Protection

The remaining tests for the differential protectiononly need to be done with current injected in onephase of one winding, unless otherwise stated.

Test 2. Time Delay of 87 Tripping: Address 1625

If Address 1625 = 0.00 seconds , skip to the nexttest.

Two options for testing Address 1625 are presented.With one exception, Option 1 is recommendedbecause more accurate results are produced.Option 1 does require a standalone timer that isstarted on a contact closure, and stopped on aclosure of a second contact. If Address 1625 isinfinite (+∗) seconds, Option 2 should be performed.

7UT51 v3

PRCM-1108A-0199 27

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1TripContact 1

W1

W2

W3(7UT513only)

5A15A2

STOP

START

TimerOption 1

TimerOption 2

STOP

START I1 ON

ConnectionOption 2

Connect to onephase of onewindingwith lowest87-Itrip (Wx)

TripContact 2


Connect the 7UT51 as shown in Figure 12. Anyphase can be selected for current injection. Tominimize current requirements, choose a phase ofthe winding that has the lowest 87-Itrip(Wx). This istypically a phase of Winding 1 (high-voltage side ofthe transformer).

Option 1 :

1. Program Trip Relay 1 for 5691 87-Diffprotection: Trip . (The default setting issufficient.)

2. Program Trip Relay 2 for 5621 87-Differentialunit pickup.

3. Set the test current magnitude for a value thatwill provide a solid pickup of 87, based on theresults from Test 1. A magnitude equal to twice87-Itrip(Wx) is good. Be certain not to pick upthe highset unit, Address 1604.

4. Set the timer to start on the closure of thecontact from Trip Relay 2, and stop on theclosure of the contact from Trip Relay 1.

5. Suddenly apply the current.

6. Record the value from the timer. This is thetested value of Address 1625. If Address 1625is infinite (+*) seconds, the timer should notstop.

7. Turn Off the current, and reset the LEDs andLCD.

8. Program trip relays 1 and 2 for the originalsettings.

Option 2 :

1. Program Trip Relay 1 to include 5691 87-Diffprotection: Trip. (The default setting includesthis signal.)

2. Set the test current magnitude for a value thatwill provide a solid pickup of 87, based on theresults from Test 1. A magnitude equal to twice87-Itrip(Wx) is good. Be certain not to pick upthe high-set unit, Address 1604.

3. Set the timer to start on the application ofcurrent, and stop on the closure of the contactfrom Trip Relay 1.

4. If Address 1625 is infinite (+*) seconds,continue to Step 5. Otherwise, skip to Step 8.


6. Verify the timer does not stop, and no othercontacts or LEDs programmed for the trippingof 87 operate. (Action from the pickup of 87 isproper.)

7. Turn Off the current, and reset the LEDs andLCD if applicable. End of test.

8. Set Address 1625 = 0.00 seconds .


10. Record the pickup time of 87 plus the outputcontact, turn off current.

11. Repeat steps 9 and 10 two or more times, toobtain a pickup timespread for 87 and contact.

12. Set Address 1625 for the desired value.

13. Repeat steps 9-10. The recorded time nowincludes Address 1625.

14. Reset the LEDs and LCD.

15. Program Trip Relays 1 for the original setting.

Expected Results:

Option 1 :

The value read from the timer is the direct, testedvalue for Address 1625. The value should be withinthe larger of +/- 3% or +/-13 ms of Address 1625.

Operations of the contacts, LEDs, and LCD shouldbe consistent with those in the Test 1, withconsideration given to the changing of theprogramming for Trip Relays 1 and 2.

7UT51 v3

28 PRCM-1108A-0199

Option 2:

The pickup times from Step 11 (1625 = 0.00seconds ) must be subtracted from the pickup timeof Step 13 (1625 = desired setting) to obtain thetested value for Address 1625. The accuracy ofAddress 1625, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms. The pickuptimespread of 87 (without delay) plus contact mustbe considered.

The pickup timespread of 87 plus contact can adderrors and uncertainty to the results. If the user isnot satisfied with the calculated values for Address1625, the Network Disturbances option in theWinDIGSI software can be useful.

Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor Event 5621 from the time for Event 5691 to getthe delay in tripping caused by Address 1625.

Operations of the contacts, LEDs, and LCD shouldbe consistent with those in the Test 1, withconsideration given to the changing of theprogramming for Trip Relay 1.

Test 3. Trip Dropout after Reset of 87:Address 1627

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)

TimerSTOP

START I1 OFF

Connect to onephase of onewinding withlowest

87-Itrip (Wx)


Connect the 7UT51 as shown in Figure 13. Anyphase can be selected for current injection. Tominimize current requirements, choose a phase ofthe winding that has the lowest 87-Itrip(Wx). This istypically a phase of Winding 1 (high-voltage side ofthe transformer).


2. Program Trip Relay 1 to include 5691 87-Diffprotection: Trip . (The default setting issufficient.)

3. Set the test current magnitude for a value thatwill provide a solid pickup of 87, based on theresults from Test 1. A magnitude of twice 87-Itrip(Wx) is good. Be certain not to pickup thehighset unit, Address 1604.

4. Set the timer to start when the current is turnedOff , and stop when the contact transitions fromclosed to open.

5. Apply the current to Trip 87.

6. Turn Off the current.

7. Record the trip dropout time given by the timer.

8. If the desired setting of Address 1627 = 0.00seconds , stop here and end the test.Otherwise, go to the next step.

9. Repeat steps 5-7 two or more times todetermine a timespread for the dropout time of87 plus contact.

10. Set Address 1627 for the desired setting.

11. Repeat steps 5-7.

12. Program trip Relay 1 for the original setting.

Expected Results:

With Address 1627 = 0.00 seconds , the dropouttime of 87 plus contact should be 30 ms +/- 13 ms.

The dropout times from step 9 (1627 = 0.00seconds ) must be subtracted from the dropout timeof Step 11 (1625 = desired setting) to obtain thetested value for Address 1627. The accuracy ofAddress 1627, including the accuracy of the timer, isthe larger of +/- 3% or +/- 10 ms. The dropouttimespread of 87 (without delay) plus contact mustbe considered.

The operations of contacts, LEDs, and LCD shouldbe consistent with those in Test 1, with considerationgiven to the changing of the programming for TripRelay 1.

7UT51 v3

PRCM-1108A-0199 29

Notes about Testing the Differential High-SetElement: Address 1604

Tests pertaining to the high-set element (87HS) arelikely to require high currents.

Note: Do not to exceed the current limitations of the7UT51 previously mentioned in thisprocedure.

The pickup current of 87HS depends on the windinginto which current is injected.

1. Select the lowest , calculated 87-Itrip(Wx).

2. Calculate the pickup current of 87HS for thatwinding (87HS-Itrip(Wx)) such as:

87HS-Itrip (Wx) = Address 1604 x 87-I trip (Wx)Address 1603

3. If 87HS-Itrip(Wx) is 20 amps or less (4 amps orless for a 7UT51 with a 1 amp rating), performtests 4, 5, and 6. Otherwise, perform only tests5 and 6.

If the 87HS pickup current is less than 20 amps, aprecise pickup level is determined in Test 4. If thepickup current is greater than 20 amps, the test for aprecise pickup is foregone, and a test current of 1.2X 87HS-Itrip(Wx) is used for verification of pickup intests 5 and 6.

Tests for 87HS may cause other elements tooperate, such as those of the Overcurrent BackupProtection or the Thermal Overload Protection. Ifthis occurs, the other elements can be temporarilyturned Off (Address 2101 for Overcurrent Protectionand Address 2401 or Address 2501 for ThermalOverload Protection). If elements are turned Off ,they should remain Off until the tests for thedifferential protection are completed. Some later 87tests could also operate these other elements.

Note: Be sure to turn back on any affectedelements, after the 87/87HS tests arecompleted.

Test 4. Pickup of 87HS: Address 1604

This test is only to be done if 87HS-Itrip(Wx) is 20amps or less (4 amps or less if the 7UT51 is ratedfor 1 amp.)

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)


87HS - Itrip(Wx)

ContactMonitor

Figure 14: Connection Diagram

Connect the 7UT51 as shown in Figure 14. Injectcurrent into one phase of the winding with the lowest87HS-Itrip(Wx).

Recommended Option:

Set Address 1625 = +* (infinite) seconds . Thissetting will permit verification that 87HS trippingoperates contacts that are programmed for both 87and 87HS tripping. Otherwise, 87 tripping will occurbefore 87HS tripping in the test below.

1. Program Trip Relay 1 to include 5692 87HS-Diffprotection: Trip . (The default setting includesthis.)

2. Turn On the current and slowly increase thecurrent until 87HS trips, as indicated by theLEDs or contacts.

3. Turn Off the current and reset targets.4. Set Address 1625 for the desired setting if a

change was made.

Note: Regardless of the setting of Address 1625,the contact of Trip Relay 1 will not reset inthe above test until 87 drops out. Thedropout of 87 is tested above; therefore, notrepeated here.

7UT51 v3

30 PRCM-1108A-0199

Expected Results:

Pickup CurrentThe pickup current at contact closure should bewithin +/- 5% of the calculated 87HS-Itrip(Wx).

Contacts, LEDs, and LCD

For the default settings with Address 1625 = infiniteseconds , all trip contacts should close, signal relays1 and 2 should operate, and LEDs 1 and 3 shouldlight when 87HS trips. When the current is turnedOff , the contacts should open, the LCD shoulddisplay 87Diff GenFlt and 87DiffGenTrip , and theLEDs remain latched. With Address 1625 equal toanother setting, the same target and contactoperations should occur, except LED 2 should alsolight and latch.

Test 5. Time Delay of 87HS Trip: Address 1626

If Address 1626 = 0.00 seconds , skip to the nexttest.

This test requires 87HS to be solidly picked up for atime greater than Address 1626. To simplify theprocedure and alleviate concerns about thermaldamage to the 7UT51, a setting change of Address1604 (87HS pickup) may be required.

Two options for testing the Address 1626 arepresented. With one exception, Option 1 isrecommended because more accurate results areproduced. Option 1 does require a standalone timerthat is started on a contact closure, and stopped ona closure of a second contact. If Address 1626 isinfinite (+*) seconds, Option 2 should be performed.

Connect the 7UT51 as shown in Figure 15. Applycurrent to one phase of the winding with the lowest87HS-Itrip(Wx).

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1

TripContact 1

W1

W2

W3(7UT513only)

5A15A2

STOP

START

TimerOption 1

TimerOption 2 STOP

START I1 ON

ConnectionOption 2

Connect to onephase of onewindingwith lowest87-trip (Wx)

TripContact 2


7UT51 v3

PRCM-1108A-0199 31

Option 1:

1. If 87HS-Itrip(Wx) > 16.5 amps,change Address 1604 so that 87HS-Itrip(Wx) ≤16.5 amps. The new setting is determined by:

New Address 1604 ≤

[16.5 X Existing Address 1604]Existing 87HS-I trip (Wx)

If 87HS-Itrip(Wx) ≤ 16.5 amps,no setting changes are needed.

2. Set Address 1625 = +* (infinite) seconds .

3. Program Trip Relay 1 for 5692 87HS-Diffprotection: Trip . (The default setting issufficient.)

4. Program Trip Relay 2 for 5622 87-HS-Diff protunit picked up .

5. Set the current source for 20 amps (4 amps for a7UT51 with a 1amp rating).



8. Record the value from the timer. This is thetested value for Address 1626. If Address 1626is infinite (+*) seconds, the timer should not stop.


10. Program Trip Relays 1 and 2 for the originalsettings.

11. Reset Address 1625 for the desired setting.

Option 2:

1. If 87HS-Itrip(Wx) > 16.5 amps,

change Address 1604 so that 87HS-Itrip(Wx) ≤16.5 amps. The new setting is determined by:

New Address 1604 ≤[16.5 X Existing Address 1604]

Existing 87HS-I trip (Wx)



3. Program Trip Relay 1 to include 5692 87HS-Diffprotection: Trip . (The default setting includesthis signal.)

4. Set the current source for 20 amps (4 amps for a7UT51 with a 1amp rating).

5. Set the timer to start on the application ofcurrent, and stop on the closure of the contact.

6. If Address 1626 is infinite (+*) seconds ,continue to Step 7. Otherwise, skip to Step 10.


8. Verify that the timer does not stop, and no othercontacts or LEDs programmed for the tripping of87HS operate. (Action from the pickup of 87HSis proper.)

9. Turn Off the current, and reset the LEDs andLCD, if applicable. End the test.



12. Record the pickup time of 87HS plus the outputcontact, and turn off the current.

13. Repeat steps 11 and 12 two or more times, toobtain a pickup timespread for 87HS andcontact.




17. Program Trip Relay 1 for the original settings.


Expected Results:Option 1:

The value read from the timer is the direct, testedvalue for Address 1626. The value should be within+/- 3% or +/- 13 ms of Address 1626.

For the default settings, all trip contacts shouldclose, signal relays 1 and 2 should operate, andLEDs 1 and 3 should light when Address 1626expires. When the current is turned off, the contactsshould reset, the LEDs should remain latched, andthe LCD should display 87Diff GenFlt and87DiffGenTrip .

Option 2:

The pickup times from Step 13 (1626 = 0.00seconds ) must be subtracted from the pickup timeof Step 15 (1626 = desired setting) to obtain thetested value for Address 1626. The accuracy ofAddress 1626, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms. The pickup

7UT51 v3

32 PRCM-1108A-0199

timespread of 87HS (without delay) plus contactmust be considered.

The pickup timespread of 87HS plus contact canadd errors and uncertainty to the results. If the useris not satisfied with the calculated value for Address1626, the Network Disturbances option in theWinDIGSI software can be useful.

Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor signal 5622 coming from the time for signal 5692coming to get the delay in tripping caused byAddress 1626.

For the example settings, all Trip contacts shouldclose, signal relays 1 and 2 should operate,and LEDs 1 and 3 should light whenAddress 1626 expires. When the current isturned Off , the contacts should reset, theLEDs should remain latched, and the LCDshould display 87Diff GenFlt and87DiffGenTrip .

Test 6. Trip Dropout after Reset of 87HS:Address 1627

Address 1627 applies to both 87 and 87HS. Test 3applies for an 87 trip. This test is done with an87HS trip.This test requires 87HS to be solidly picked up. Tosimplify the procedure and alleviate concerns aboutthermal damage to the 7UT51, a setting change ofAddress 1604 (87HS pickup) may be required.

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)

TimerSTOP

START I1 OFF


87-Itrip (Wx)


Connect the 7UT51 as shown in Figure 16. Injectcurrent into one phase of the winding with the lowest87HS-Itrip(Wx).

1. If 87HS-Itrip(Wx) > 16.5 amps,change Address 1604 so that87HS-Itrip(Wx) ≤ 16.5 amps.

The new setting is determined by:New Address 1604 ≤ [16.5 x Existing Address 1604]Existing 87HS-I trip (Wx)




4. Program Trip Relay 1 to include 5692 87HS-Diffprotection: Trip . (The default setting issufficient.)

5. Set the current source for 20 amps (4 amps for a7UT51 rated for 1 amp).

6. Set the timer to start when the current is turnedOff , and stop when the contact transitions fromClosed to Open .

7. Apply the current to pickup 87HS.


9. Record the trip dropout time given by the timer.

10. If the desired setting of Address 1627 = 0.00seconds , stop here and end the test.Otherwise, go to the next step.

11. Repeat steps 7-9 two or more times todetermine a timespread for the dropout time of87HS plus contact.





16. Program Trip Relay 1 for the original settings.

Expected Results:

With Address 1627 = 0.00 seconds , the dropouttime of 87HS plus the contact should be 30 ms +/-13 ms.

The dropout times from step 11 (1627 = 0.00seconds ) must be subtracted from the dropout timeof Step 13 (1625 = desired setting) to obtain thetested value for Address 1627. The accuracy of

7UT51 v3

PRCM-1108A-0199 33

Address 1627, including the timer accuracy, is thelarger of +/- 3% or +/- 10 ms. The dropouttimespread of 87HS (without delay) plus contactmust be considered.

For the default settings, all trip contacts shouldclose, signal relays 1 and 2 should operate, andLEDs 1 and 3 should light when 87HS trips. Whenthe current is turned Off , the contacts should reset,the LEDs should remain latched, and the LCDshould display 87Diff GenFlt and 87DiffGenTrip .

Test 7. Second Harmonic RestraintPer-Phase: Address 1611

IC

IB

IA

Ic

Ib

IaI2(N x60Hz)


ContactMonitor

TripContact 1I1

(60 Hz)

Connect to onephase of onewindingwith lowest87-Itrip ( Wx ) W1

W2

W3 (7UT513 only)

not shown


Connect the 7UT51 as shown in Figure 17. Anyphase can be selected for current injection. Tominimize current requirements, choose a phase ofthe winding that had the lowest 87-Itrip(Wx) from Test1. This is typically a phase of Winding 1 (high-voltage side of the transformer).

1. Program Trip Relay 1 to include 5691 87-Diffprotection: Trip . (The default settings aresufficient.)

2. Set the 60 Hz current (Source 1) for a solidpickup of 87. Usually a value of 2 X 87-Itrip (Wx)is a good choice. Avoid operation of 87HS orexceeding the continuous current rating of the7UT51.

3. Set the Source 2 current frequency for 120 Hzand the magnitude equal to [Source 1 current XAddress 1611 in decimal format].

4. Apply only Source 1 current to verify 87 tripping.

5. Turn Off Source 1. Reset targets.

6. Simultaneously apply both currents.

7. Observe the response of the 7UT51 andsimultaneously turn off both currents.

8. Repeat steps 6 and 7, slightly adjusting theSource 2 current magnitude while the currentsare Off , until the minimum Source 2 currentmagnitude for restraint is found.

9. Keep Trip Relay 1 programmed as in Step 1until the end of Test 13.

Expected Results:

The percent of second harmonic current required forrestraint is:

%Second Harmonic Restraint=[120 Hz current from Step 8] x 100% [60 Hz current from Step 8]

The result should be within +/- 5% of Address 1611.

If 87 tripping occurs, operations of the contacts,LEDs, and LCD should be consistent with Test 1.

If harmonic restraint occurs, LEDs and contactsprogrammed to operate for 87 tripping should notoperate. After current is turned Off , an LCDmessage may appear. For the default settings, themessage should be 87Diff GenFlt .

7UT51 v3

34 PRCM-1108A-0199

Test 8. N th Harmonic RestraintPer-Phase: Addresses 1613and 1614

This test only needs to be done if Address 1613 isnot Off .

Repeat Test 7 with these exceptions:• Set the Source 2 current frequency to match

Address 1613: 3rd harmonic is 180 Hz, 4th

harmonic is 240 Hz, and 5th harmonic is 300 Hz.• Set the Source 2 current magnitude in step 2 for

[Source 1 Current Magnitude X Address 1614 indecimal format].

Expected Results:

The percent of Nth harmonic current required forrestraint is:

%Nth Harmonic Restraint =

[Nth Harmonic current from Step 8] X 100% [60 Hz current from Step 8]


Targets and contact operation should be the sameas Test 7.

Test 9. Differential Current StoppingNth Harmonic Restraint: Address 1616

This test only needs to be done if Address 1613 isnot Off .

Use the same 7UT51 connections from Test 8(Figure 17).

1. Set the magnitude of the 60 Hz current (Source1) for:

60 Hz magnitude =

0.9 x 87-Itrip (Wx) x [Address 1616] [Address 1603]

2. Set the magnitude of the Nth harmonic current(source 2) for:

(N X 60 Hz) magnitude = 60 Hz magnitude0.9

3. Simultaneously apply both currents and verify 87is restrained.

4. Slowly increase the magnitude of the 60 Hzcurrent (Source 1) until 87 tripping occurs.

Expected Results:

The magnitude of the 60 Hz current at which trippingof 87 occurs should be within +/- 7% of:

87-Itrip (Wx) X [Address 1616][Address 1603]

Targets and contact operation should be the sameas Test 7.

Test 10. Cross-Blocking, N th Harmonic,Minimum Pickup: Address 1615

If Address 1613 = Off or Address 1615 = 0 cycle ,skip this test.

IC

IB

IA

Ic

Ib

IaI2(N x 60Hz)


ContactMonitorTrip Contact 1I1

(60 Hz)

Example connections forW1. Use winding with thelowest 87-Itrip (Wx) W3 (7UT513 only)

not shown

W1

W2


This test only needs to be done for one winding, with60 Hz current injected into two phases of thatwinding, and Nth harmonic current injected into oneof the phases that has the 60 Hz current.

Connect the 7UT51 as shown in Figure 18. Anywinding can be selected for current injection. Tominimize current requirements, choose the windingthat has the lowest 87-Itrip(Wx). This is typicallyWinding 1 (high-voltage side of the transformer).For clarity, Figure 18 is drawn with the currentconnections to W1. Adapt if necessary.

7UT51 v3

PRCM-1108A-0199 35

1. Set Address 1615 = 0 cycle .

2. Set the 60 Hz current (source 1) for a solidpickup of 87. Usually a value of 2 X 87-Itrip(Wx)is a good choice. Avoid operation of 87HS,exceeding Address 1616 (Test 9), or exceedingthe continuous current rating of the 7UT51.

3. Set the source 2 current frequency to matchAddress 1613: 3rd harmonic is 180 Hz, 4th

harmonic is 240 Hz, and 5th harmonic is 300 Hz.

4. Set the source 2 current magnitude equal to[Source 1 current X Address 1614 in DecimalFormat].

5. Simultaneously apply both currents to verify 87trip.

6. Turn Off both currents. Reset targets.

7. Set Address 1615 = +* (infinite) cycles.


9. Observe the response of the 7UT51 andsimultaneously turn off both currents.

10. Repeat steps 8 and 9, slightly adjusting themagnitude of the source 2 current while thecurrents are off, until the minimum source 2current magnitude for restraint is found.


Expected Results:

The percent of Nth harmonic current required forrestraint is:

%Nth Harmonic Restraint =

[NthHarmonic Current from Step 10]X100%[60 Hz current from Step 10]


For the default settings, contact and targetoperations should be consistent with Test 1 if 87tripping occurs.

If harmonic restraint occurs, LEDs and contactsprogrammed to operate for 87 tripping should notoperate. After current is turned off, an LCDmessage may appear. For the default settings, themessage should be 87Diff GenFlt .

Test 11. Cross-Blocking, Second Harmonic,Minimum Pickup: Address 1612

If Address 1612 = 0 cycle , skip this test.

Follow Test 10 with these exceptions:

• Substitute Address 1612 for Address 1615 insteps 1, 7, and 10.

• Set the Source 2 frequency to 120 Hz in Step 3.

• Set the Source 2 current magnitude in Step 4 for[Source 1 Current Magnitude X Address 1611 indecimal format].

Expected Results:


%Second Harmonic Restraint =[120 Hz Current from Step 10] X 100%[60 Hz current from Step 10]

The result should be within +/- 5% Address 1611.

For the default settings, contact and targetoperations should be the same as Test 10.

Test 12. Cross-Blocking, Second Harmonic,Time Delay: Address 1612

If Address 1612 = 0 cycle or +* (infinite) cycles,skip this test.

IC

IB

IA

Ic

Ib

Ia I2(N x 60Hz)


Trip Contact 1I1(60 Hz)

Exampleconnections forW1. Usewinding with thelowest 87-Itrip(Wx)

Start I1 ON

STOP

Timer

W3 (7UT513)

not shown


This test only needs to be done for one winding, with60 Hz current injected into two phases of that

7UT51 v3

36 PRCM-1108A-0199

winding, and 120 Hz current injected into one of thephases that has the 60 Hz current.

Connect the 7UT51 as shown in Figure 19. Anywinding can be selected for current injection. Tominimize current requirements, choose the windingthat has the lowest 87-Itrip(Wx). This is typicallyWinding 1 (high voltage side of the transformer). Forclarity, Figure 19 is drawn with the currentconnections to W1. Adapt if necessary.



3. Set the 60 Hz current (Source 1) for a solidpickup of 87. Usually a value of [2 X 87-Itrip(Wx)]is a good choice. Avoid operation of 87HS orexceeding the continuous current rating of the7UT51.

4. Set the Source 2 current frequency to 120 Hz,and the magnitude equal to the magnitude of theSource 1 current.

5. Set the timer to start on the application of 60 Hzcurrent (Source 1), and stop on the closure ofthe contact.

6. Turn On Source 1 only.

7. Record the tripping time of 87 and contact, andturn off Source 1.

8. Repeat steps 6 and 7 two times to obtain atimespread of the tripping of 87 and contact.

9. Set Address 1612 = desired setting.

10. Simultaneously apply both Source 1 and Source2 currents.

11. Record the value from the timer, which nowincludes Address 1612.

12. Turn Off both currents, and reset the LEDs andLCD.

13. Reset Address 1625 to the desired value.

Expected Results:

The pickup times from step 8 must be subtractedfrom the pickup time from Step 11 (1612 = desiredsetting) to obtain the tested value for Address 1612.The accuracy of Address 1612 is +/- 1.02 cycles(timer accuracy included). The pickup timespread of87 plus contact must be considered in the result.


Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit. SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Indications ofevents 5641 and 5642 should be seen. Then thereduction of Event 5641 (cross-blocking of Ph Aceases) should be seen at the same time that theevents 5621 and 5691 (87 tripping) increase.Subtract the coming time of 5641 from the goingtime of 5641 to obtain Address 1612.

The LEDs, LCD, and contact operations should bethe same as those for Test 1. The delay betweencurrent application and tripping may be noticeable,depending on the desired setting of Address 1612.

Test 13. Cross-Blocking, N th Harmonic, TimeDelay: Address 1615

If Address 1615 = 0 cycle or +* (infinite) cycles,skip this test.

Connect the 7UT51 as shown in Figure 19 (Test 12).Any winding can be selected for current injection.To minimize current requirements, choose thewinding that has the lowest 87-Itrip(Wx). This istypically Winding 1 (high voltage side of thetransformer). For clarity, Figure 19 is drawn with thecurrent connections to W1. Adjust if necessary.

This test only needs to be done for one winding, with60 Hz current injected into two phases of thatwinding, and 120 Hz current injected into one of thephases that has the 60 Hz current.



3. Set the 60 Hz current (Source 1) for a solidpickup of 87. Usually a value of [2 X 87-Itrip(Wx)] is a good choice. Avoid operation of87HS or exceeding the continuous current ratingof the 7UT51.

4. Set the Source 2 current frequency to matchAddress 1613: 3rd harmonic is 180 Hz, 4th

harmonic is 240 Hz, and 5th harmonic is 300 Hz.

5. Set the Source 2 current magnitude equal to themagnitude of the Source 1 current.

6. Set the timer to start on the application of 60 Hzcurrent (Source 1), and stop on the closure ofthe contact.

7. Turn On Source 1 only.

7UT51 v3

PRCM-1108A-0199 37

8. Record the tripping time of 87 and contact andturn Off Source 1.

9. Repeat steps 7 and 8 two times to obtain atimespread of the tripping of 87 and contact.

10. Set Address 1615 = desired setting.

11. Simultaneously apply both Source 1 and Source2 currents.

12. Record the value from the timer, which nowincludes Address 1615.

13. Turn Off both currents, and reset the LEDs andLCD.

14. Reset Address 1625 to the desired value.

Expected Results:

The pickup times from Step 9 must be subtractedfrom the pickup time from Step 12 (1615 = desiredsetting) to obtain the tested value for Address 1615.The accuracy of Address 1615 is +/- 1.02 cycles(timer accuracy included). The pickup timespread of87 plus contact must be considered in the result.


Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. The coming ofevents 5641 and 5642 should be seen. Then thegoing of Event 5641 (cross-blocking of Ph A ceases)should be seen at the same time of the coming ofevents 5621 and 5691 (87 tripping). Subtract thecoming time of Event 5641 from the going time ofEvent 5641 to obtain Address 1615.The LEDs, LCD, and contact operations should bethe same as those for Test 1. The delay betweencurrent application and tripping may be noticeable,depending on the desired setting of Address 1615.

Note: Reset Trip Relay 1 to the original, desiredsetting.

Notes about Simulating Through-Faults andTesting the 87 Slopes

The next test is performed to verify the security ofthe 7UT51 for external faults (through-faults). Theslopes of the 87 characteristic are tested after thethrough-fault. The slope tests are slight variations ofthe through-fault test.

If the through-fault or slope tests cause tripping ofunits other than 87, such as the backup overcurrentunits, these other units can be temporarily madenonexistent with the settings in Address Block 7800.Be sure to undo any setting changes in AddressBlock 7800 when the differential element tests arefinished.

Since the current transactor and current processingof each phase of each winding are verified in Test 1,only one fault needs to be simulated for the through-fault and slope tests.

The current distribution sensed by a 7UT51, for anexternal fault, depends on the fault type andlocation, the connections of the transformerwindings, and the CT connections.

Three cases are detailed below to provide examplesof possible methods for simulating through-faults, intesting the security of a 7UT51. Each case involvestwo-winding, delta-grounded wye transformers.Users with other applications can consider the casesand the comments at the end of this notes section,and adapt the procedure accordingly.

Case 1: delta-grounded wye transformers with thedelta winding being the reference winding (Winding1).

Case 2: delta-grounded wye transformers with thewye winding being Winding 1. Zero sequencecurrent processing (Address 1106) set for I0 –elimination .

Case 3: delta-grounded wye transformers with thewye winding being Winding 1. Zero sequencecurrent processing (Address 1106) set for I0 –correction .

Note: The assumptions for the three cases are thatall CTs are wye-connected; all commonpoints of the CTs are towards the transformer(Addresses 1105 and 1125); all CTs aresubtractive with the secondary polaritiesconnected to the polarities of the 7UT51current inputs; zero sequence currentprocessing is without for the delta-side of thetransformer; and the rotation is ABC.

7UT51 v3

38 PRCM-1108A-0199

For all three cases, the fault simulated is anexternal, phase-ground fault on the wye-side of thetransformer. This is the simplest fault to simulateusing two test-current sources.

Consider the common, ANSI connected, deltagrounded wye transformer shown in Figure 20. Letcurrents be defined as flowing into the transformer(both sides). For an a-phase-ground fault resultingin a current of 1.0 per unit through the transformerwinding to the fault, IA = -IC. Also, IA = 0.58 per unitor (1/1.732) per unit for Ia = -1.0 per unit. If the faultis on b-phase, with Ib = -1.0 per unit, then IB = -IA =(1/1.732) per unit. If the fault is on c-phase, with Ic =-1.0 per unit, then IC = -IB = (1/1.732) per unit.These current relationships that result for phase-ground faults on the wye side are used in the testsbelow.

1.0 p.u.

a

b

c

0.58 p.u.

0.58 p.u.

0.58 p.u.

A

C

B

Figure 20: Dy1 Transformer, a-Phase-Ground Fault

If the delta winding in Figure 20 is considered thereference winding, this transformer is called a Dy1transformer. The D is capitalized to indicate thedelta winding is the reference. The 1 means thepositive sequence, a-phase-voltage-neutral (V1an)LAGS the positive sequence A-phase-voltage-neutral (V1AN) by (1 X 30°). By connecting thepower system phases to different wye side windings(maintaining ABC rotation), or by reversing thepolarity of the three wye side windings andconnecting the power system phases in variouscombinations, different phase shifts are obtained.The possibilities are Dyz, where z is an integermultiplied by 30° to indicate the angle by which V1anlags V1An, and z = 1, 3, 5, 7, 9, or 11. The 7UT51instruction manual has excellent diagrams of theDyz transformers showing the transformer windingconnections and power system phase connections.

For all Dyz transformers, any phase-ground fault onthe wye side with –1.0 per unitcurrent results in (1/1.732) per unit current in onephase of the delta side, and –(1/1.732) per unit ofcurrent in another phase of the delta side. Thephases involved depend on z, and the faultedphase.

Since all of the current inputs are checked in Test 1,only one simulation of one phase-ground fault needsto be done to check the security of the 7UT51 forthrough-faults, and test the slopes of the 87characteristic. There is sufficient information belowfor the user to simulate a fault on any of the phases.

A source of positive and negative sequence currentson the delta side is assumed in Figure 20, as is aradial or open system on the wye side. For testingthe 7UT51, these assumptions are not important. Arecommendation in this procedure is that when theuser runs the through-fault and slope tests below,the user should model the simplest fault, that can besimulated with two test currents, with the transformerconnected to a power system in the simplest way. Ifthe simulation is unrealistic for the application, this isnot important. The differential characteristic will beadequately checked.

The user must know the transformer winding beingconsidered by the 7UT51 as the reference winding.This can be determined by viewing the settings inAddress Block 1100.

Note: Addresses 1102-1108 apply to the referencewinding (Winding 1).Addresses 1121-1128 apply to Winding 2.Addresses 1141-1148 apply to Winding 3.

If Winding 1 is a grounded wye winding, the usermust know the processing done, by the 7UT51, onthe zero sequence currents of the winding. Theprocessing determines the required test connectionsbelow. See Address 1106.

Case 1: Delta-Grounded Wye Transformers,Delta is Reference Winding (Dyz)

7UT51 Connections

Figure 21 shows the connections for a Dy1transformer, with an a-phase-ground fault simulated.The connections for all Dyz transformers and allphase-ground faults are below.

7UT51 v3

PRCM-1108A-0199 39

IC

IB

IA

Ic

Ib

Ia

I1

I2


Note polarity oftest sources.

ContactMonitorTrip Contact 1

Figure 21: Test Connections for Dy1 Transformerwith a-Phase-ground Through-Fault

Notes:• I1* is the terminal with polarity of Test-Source 1.

• I1 is the terminal without polarity ofTest-Source 1.

• I2* and I2 are similar, applying to Test-Source 2.

• IA*, IB*, and IC* are the Winding 1 phase A, B,and C current-terminals with polarity.

• IA, IB, and IC are the Winding 1 current-terminalswithout polarity.

• Ia*, Ib*, Ic*, Ia, Ib, and Ic are similar except theyapply for Winding 2.

Source 2 Test-Current Connections for Winding 2 –ALL Dyz transformer types. The letter in theparenthesis denotes the Winding 2 phase faultedto ground.

(a) [I2* to Ia (terminal 3B2)] and [I2 to Ia*(terminal 3B1)]

(b) [I2* to Ib (terminal 2B2)] and [I2 to Ib*(terminal 2B1)]

(c) [I2* to Ic (terminal 1B2)] and [I2 to Ic*(terminal 1B1)]

Table 7: Source 1 Current- Connections, Delta-Grounded Wye Transformers (Dyz)

Transf.Type

Source 1 Test-Current Connections( ) Indicates Phase faulted to ground

Dy1 (a) [I1* to IA* (3A1)] ; [I1 to IC* (1A1)] ;Jumper IA to IC (3A2 to 1A2)(b) [I1* to IB* (2A1)] ; [I1 to IA* (3A1)];Jumper IB to IA (2A2 to 3A2)(c) [I1* to IC* (1A1)] ; [I1 to IB* (2A1)];Jumper IC to IB (1A2 to 2A2)

Dy3 (a) [I1* to IB* (2A1)] ; [I1 to IC*(1A1)] ;Jumper IB to IC (2A2 to 1A2)(b) [I1* to IC* (1A1)] ; [I1 to IA* (3A1)];Jumper IC to IA (1A2 to 3A2)(c) [I1* to IA* (3A1)] ; [I1 to IB* (2A1)] ;Jumper IA to IB (3A2 to 2A2)

Dy5 (a) [I1* to IB* (2A1)] ; [I1 to IA* (3A1)] ;Jumper IB to IA (2A2 to 3A2)(b) [I1* to IC* (1A1)] ; [I1 to IB* (2A1)] ;Jumper IC to IB (1A2 to 2A2)(c) [I1* to IA* (3A1)] ; [I1 to IC* (1A1] ;Jumper IA to IC (3A2 to 1A2)

Dy7 (a) [I1* to IC* (1A1)] ; [I1 to IA* (3A1)];Jumper IC to IA (1A2 to 3A2)(b) [I1* to IA* (3A1)] ; [I1 to IB* (2A1)];Jumper IA to IB (3A2 to 2A2)(c) [I1* to IB* (2A1)] ; [I1 to IC* (1A1)] ;Jumper IB to IC (2A2 to 1A2)

Dy9 (a) [I1* to IC* (1A1)] ; [I1 to IB* (2A1)];Jumper IC to IB (1A2 to 2A2)(b) [I1* to IA* (3A1)] ; [I1 to IC* (1A1)];Jumper IA to IC (3A2 to 1A2)(c) [I1* to IB* (2A1)] ; [I1 to IA* (3A1)];Jumper IB to IA (2A2 to 3A2)

Dy11 (a) [I1* to IA* (3A1)] ; [I1 to IB* (2A1)];Jumper IA to IB (3A2 to 2A2)(b) [I1* to IB* (2A1)] ; [I1 to IC* (1A1)];Jumper IB to IC (2A2 to 1A2)(c) [I1* to IC* (1A1)] ; [I1 to IA* (3A1)];Jumper IC to IA (1A2 to 3A2)

The 7UT51 determines restraint and differentialcurrents as such (two-winding):

IAREST = IA** + Ia**IBREST = IB** + Ib**ICREST = IC** + Ic**IADIFF = IA** + Ia** (phasor sum)IBDIFF = IB** + Ib** (phasor sum)ICDIFF = IC** + Ic** (phasor sum)

The I** currents are not actual currents. They arequantities mathematically derived by the 7UT51using the actual currents into the 7UT51. Thederivations differ depending on the selection of

7UT51 v3

40 PRCM-1108A-0199

Winding 1, the connection of the transformerWinding 2, and the processing of the zero-sequencecurrents.

Knowledge of the equations for the I** is notessential for the tests below; however, the equationsdo allow the user to understand better the operationof the 7UT51. The equations also allow theprocedure to be adapted easier if the user is testingthe 7UT51 for applications other than the threecases mentioned above. Consult the instructionbook or Siemens to obtain the equations.

For Dyz transformers, the equations for I** are givenimmediately below and in Table 8. The table alsoprovides the metering values to expect whensimulating a phase-ground, through-fault on theWinding 2 side.

The equations for the Winding 1 I** currents are thesame for all Dyz transformers.

IA**=(1/3)[2IA – IB – IC] in per unit of INsecW1

IB**=(1/3)[-IA + 2IB – IC] in per unit of INsecW1

IC**=(1/3)[-IA – IB + 2IC] in per unit of INsecW1

The winding currents are phasors! The positivedirection for a winding current in this case 1 is intothe polarity terminals IA*, IB*, and IC* (terminals 3A1,2A1, and 1A1).

The equations for the Winding 2 I** currents are inTable 8. The winding currents are phasors with asimilar definition of positive direction.

Table 8: Equations of Winding 2 Currents forIREST and IDIFF, and Relationship of RestraintCurrents for Phase-Ground, Through-Faults.

Transf.Type

Relationship ofRestraint Currentsfor Phase-Ground,Through-Faults onW2 Terminals. ( )Denotes FaultedPhase

Winding 2 Currentsfor I REST and I DIFF inper unit of I NsecW2

Dy1 (a)IA** + Ia** =IC** + Ic**(b)IB** + Ib** =IA** + Ia**(c)IC** + Ic** =IB** + Ib**

Ia**=(0.577)[Ia – Ib]

Ib**=(0.577)[Ib – Ic]

Ic**= (0.577)[-Ia + Ic]

Dy3 (a)IB** + Ib** =IC** + Ic**(b)IC** + Ic** =IA** + Ia**(c)IA** + Ia** =IB** + Ib**

Ia**=(0.577)[-Ib + Ic]

Ib**=(0.577)[Ia – Ic]

Ic**=(0.577)[-Ia + Ib]

Dy5 (a)IB** + Ib** =IA** + Ia**(b)IC** + Ic** =IB** + Ib**(c)IA** + Ia** =IC** + Ic**

Ia**=(0.577)[-Ia + Ic]

Ib**=(0.577)[Ia – Ib]

Ic**=(0.577)[Ib – Ic]

Dy7 (a)IC** + Ic** =IA** + Ia**(b)IA** + Ia** =IB** + Ib**(c)IB** + Ib** =IC** + Ic**

Ia**=(0.577)[-Ia + Ib]

Ib**=(0.577)[-Ib + Ic]

Ic**=(0.577)[Ia – Ic]

Dy9 (a)IC** + Ic** =IB** + Ib**(b)IA** + Ia** =IC** + Ic**(c)IB** + Ib** =IA** + Ia**

Ia**=(0.577)[Ib – Ic]

Ib**=(0.577)[-Ia + Ic]

Ic**=(0.577)[Ia – Ib]

Dy11 (a)IA** + Ia** =IB** + Ib**(b)IB** + Ib** =IC** + Ic**(c)IC** + Ic** =IA** + Ia**

Ia**=(0.577)[Ia – Ic]

Ib**=(0.577)[-Ia + Ib]

Ic**=(0.577)[-Ib + Ic]

7UT51 v3

PRCM-1108A-0199 41

Notice for the common Dy1 transformer, with an a-phase-ground through-fault (Figure 20), IC = -IA, IB= 0, and Ib = Ic = 0

IA** = IA = 0.577 per unitIB** = 0IC** = -IA = -0.577 per unit

Ia** = (-0.577)(Ia) = - 0.577 per unitIb** = 0Ic** = (-0.577)(-Ia) = 0.577 per unit

Currents Ia** and Ic** have a negative factorbecause Ia flows out terminal Ia*.

IAREST = ICREST = 0.577 per unit + -0.577 perunit = 1.154 per unit

IBREST = 0 per unit + 0 per unit = 0 per unit

IADIFF = ICDIFF = 0.577 per unit + (-0.577 per unit)= 0 per unitICDIFF = 0 p.u. + 0 p.u. = 0 p.u.

If the currents in Figure 20 are increased by a factorof 1.732, then I** (non-zero currents) becomes1.0 per unit. The resulting IAREST and ICREST become2 per unit. If the currents in Figure 20 are increasedby a factor of (M X 1.732), where M is a constantchosen by the user, then IAREST and ICREST become(2 X M) per unit. Thus, with test currents set assuch:

I1 = (M X 1.732) X (0.577 X INsecW1) =[M X INsecW1 ] at 0°

I2 = [M X 1.732 X INsecW2 ]at 0°

The restraint currents become 2 X M. By adjustingM, the user can easily control the restraint current.This allows for simple testing of the 87 slopes.

The same analysis can be done for any Dyztransformer. Table 7 indicates the phase currentsinvolved. Table 8 shows the non-zero, restraintcurrents. For the test-set connections of Table 7,the same conclusion regarding test currents I1 andI2 results.

7UT51 v3

42 PRCM-1108A-0199

Case 2: Delta-Grounded Wye Transformers, Wyeis Reference Winding (Wdz), ZeroSequence Current Elimination(Address 1106 = I 0 – elimination)

7UT51 Connections:

Figure 22 shows the connections for a Yd11transformer, with an A-phase-ground fault simulated.Notice the wye winding current applies to Winding 1.Source 1 is still associated with Winding 1. Theconnections for all Ydz transformers and all phase-ground faults are below.

IC

IB

IA

Ic

Ib

Ia

I1

I2


Note polarity oftest sources.

ContactMonitorTrip Contact 1

Figure 22: Test Connections for Yd11 transformerwith A-Phase-ground Through-Fault, Io-Elimination

Source 1 Test-Current Connections for Winding 1 –ALL Ydz transformer types. The letter in theparenthesis denotes the Winding 1 phase faulted toground.

(A) [I1* to IA (terminal 3A2)] and [I1 to IA* (terminal3A1)]

(B) [I1* to IB (terminal 2A2)] and [I1 to IB* (terminal2A1)]

(C) [I1* to IC (terminal 1A2)] and [I1 to IC* (terminal1A1)]

Table 9: Source 2 Current- Connections, Delta-Grounded Wye Transformers (Ydz)

Transf.Type

Source 2 Test-Current Connections( ) Indicates Phase faulted to ground

Yd1 (A) [I2* to Ia* (3B1)] ; [I2 to Ib* (2B1)] ;Jumper Ia to Ib (3B2 to 2B2)(B) [I2* to Ib* (2B1)] ; [I2 to Ic* (1B1)];Jumper Ib to Ic (2B2 to 1B2)(C) [I2* to Ic* (1B1)] ; [I2 to Ia* (3B1)];Jumper Ic to Ia (1B2 to 3B2)

Yd3 (A) [I2* to Ic* (1B1)] ; [I2 to Ib*(2B1)] ;Jumper Ic to Ib (1B2 to 2B2)(B) [I2* to Ia* (3B1)] ; [I2 to Ic* (1B1)];Jumper Ia to Ic (3B2 to 1B2)(C) [I2* to Ib* (2B1)] ; [I2 to Ia* (3B1)] ;Jumper Ib to Ia (2B2 to 3B2)

Yd5 (A) [I2* to Ic* (1B1)] ; [I2 to Ia* (3B1)] ;Jumper Ic to Ia (1B2 to 3B2)(B) [I2* to Ia* (3B1)] ; [I2 to Ib* (2B1)] ;Jumper Ia to Ib (3B2 to 2B2)(C) [I2* to Ib* (2B1)] ; [I2 to Ic* (1B1] ;Jumper Ib to Ic (2B2 to 1B2)

Yd7 (A) [I2* to Ib* (2B1)] ; [I2 to Ia* (3B1)];Jumper Ib to Ia (2B2 to 3B2)(B) [I2* to Ic* (1B1)] ; [I2 to Ib* (2B1)];Jumper Ic to Ib (1B2 to 2B2)(C) [I2* to Ia* (3B1)] ; [I2 to Ic* (1B1)] ;Jumper Ia to Ic (3B2 to 1B2)

Yd9 (A) [I2* to Ib* (2B1)] ; [I2 to Ic* (1B1)];Jumper Ib to Ic (2B2 to 1B2)(B) [I2* to Ic* (1B1)] ; [I2 to Ia* (3B1)];Jumper Ic to Ia (1B2 to 3B2)(C) [I2* to Ia* (3B1)] ; [I2 to Ib* (2B1)];Jumper Ia to Ib (3B2 to 2B2)

Yd11 (A) [I2* to Ia* (3B1)] ; [I2 to Ic* (1B1)];Jumper Ia to Ic (3B2 to 1B2)(B) [I2* to Ib* (2B1)] ; [I2 to Ia* (3B1)];Jumper Ib to Ia (2B2 to 3B2)(C) [I2* to Ic* (1B1)] ; [I2 to Ib* (2B1)];Jumper Ic to Ib (1B2 to 2B2)

For Ydz transformers, the equations for I** are givenimmediately below and in Table 10. The table alsoprovides the metering values to expect whensimulating a phase-ground, through-fault on theWinding 1 side.

The equations for the Winding 1 I** currents are thesame for all Ydz transformers.

IA**=(1/3)[2IA – IB – IC] in per unit of INsecW1

IB**=(1/3)[-IA+2IB–IC] in per unit of INsecW1

IC**=(1/3)[-IA – IB + 2IC] in per unit of INsecW1

7UT51 v3

PRCM-1108A-0199 43

The winding currents are phasors! Thepositive direction for a winding current in this case 2is into the polarity terminals IA*, IB*, and IC*(terminals 3A1, 2A1, and 1A1).

The equations for the Winding 2 I** currents are inTable 10. The winding currents are phasors with asimilar definition of positive direction.

Table 10: Equations of Winding 2 Currents forIREST and IDIFF, and Relationship of RestraintCurrents for Phase-Ground, Through-Faults.

Transf.Type

Relationship ofRestraint Currentsfor Phase-Ground,Through-Faults onW2 Terminals. ( )Denotes FaultedPhase

Winding 2 Currentsfor I REST and I DIFF inper unit of I NsecW2

Yd1 (A) IAREST =(2)IBREST = (2)ICREST

(B) IBREST =(2)IAREST = (2)ICREST

(C) ICREST =(2)IAREST = (2)IBREST

Ia** =(0.577)[Ia – Ib]Ib** =(0.577)[Ib – Ic]Ic** =(0.577)[-Ia + Ic]




Ia** =(0.577)[-Ib + Ic]Ib** =(0.577)[Ia – Ic]Ic** = (0.577)[-Ia + Ib]




Ia** =(0.577)[-Ia + Ic]Ib** =(0.577)[Ia – Ib]Ic** =(0.577)[Ib – Ic]




Ia** =(0.577)[-Ia + Ib]Ib** =(0.577)[-Ib + Ic]Ic** =(0.577)[Ia – Ic]




Ia** =(0.577)[Ib – Ic]Ib** =(0.577)[-Ia + Ic]Ic** =(0.577)[Ia – Ib]




Ia** =(0.577)[Ia – Ic]Ib** =(0.577)[-Ia + Ib]Ic** = (0.577)[-Ib + Ic]

7UT51 v3

44 PRCM-1108A-0199

1.0 p.u.

A

B

C

0.58 p.u.

0.58 p.u.

0.58 p.u.

a

c

b

Figure 23: Yd11 Transformer “A” Phase-GroundFault

Consider the Yd11 transformer in Figure 23.Compare the Yd11 transformer to the Dy1transformer in Figure 20. They are the sametransformers with the same phasing – only thereference has changed. For the Yd11 transformer,V1an leads V1An by 30° which is the same aslagging by 330°, or (11 X 30°). For the A-phase-ground fault in Figure 23, IA = -1.0 per unit, IB = IC =0, Ia = -Ic = 0.58 per unit, and Ib = 0. Thus:

IA** = (2/3)IA = -(2/3) per unitIB** = -(1/3)IA = (1/3) per unitIC** = -(1/3)IA = (1/3) per unit

Ia** = (2)(0.577)(Ia) = (2/3) per unitIb** = (-0.577)(Ia) = -(1/3) per unitIc** = (-0.577)(Ia) = -(1/3) per unit

IAREST =-(2/3) per unit+ (2/3) per unit =(4/3) unit

IBREST = ICREST =(1/3) per unit + -(1/3) per unit =(2/3) per unit = (1/2)IAREST

IADIFF = -(2/3) per unit + (2/3) per unit) =0 per unit

IBDIFF = ICDIFF =(1/3) per unit + (-1)(1/3)per unit =0 per unit

If the currents in Figure 23 are increased by a factorof (3/2), or 1.5, then IA** and Ia** become 1.0per unit. The resulting IAREST becomes 2 per unit. Ifthe currents in Figure 23 are increased by a factor of(M X 1.5), where M is a constant chosen by the user,then IAREST becomes (2 X M) per unit. Thus, withtest currents set as such:

I1 = [M X 1.5 X INsecW1] at 0°

I2 = [(M X 1.5) X (0.577 X INsecW2 )] =[M X 0.866 X INsecW2] at 0°

The restraint current associated with the faultedphase becomes 2 X M. By adjusting M, the usercan easily control this restraint current. This allowsfor simple testing of the 87 slopes.

The same analysis can be done for any Ydztransformer. Table 9 indicates the phase currentsinvolved. Table 10 shows the restraint currents. Forthe test-set connections of Table 9, the sameconclusion regarding test currents I1 and I2 results.

Case 3: Delta-Grounded Wye Transformers, Wyeis Reference Winding (Ydz), ZeroSequence Current Correction (Address1106 = I0 – correction).

Consider first Case 2, even if the case does notapply. Cases 2 and 3 are similar.

7UT51 Connections:

Figure 24 shows the connections for a Yd11transformer, with an A-phase-ground fault simulated.Notice the wye winding current applies to Winding 1.Source 1 is still associated with Winding 1. Theconnections for all Ydz transformers and all phase-ground faults are discussed below.

7UT51 v3

PRCM-1108A-0199 45

IC

IB

IA

Ic

Ib

Ia


I1

ContactMonitorTrip

Contact 1

W1

W2

I2

1D1

1D2

2D1

2D2

INb

INa

Figure 24 : Test Connect for a Yd11 transformer,with an A-phase-ground Through-Fault, Io-Correction

Source 1 Test-Current Connections for Winding 1 –ALL Ydz transformer types. The letter in theparenthesis denotes the Winding 1 phase faulted toground.

Current INa Used for Zero Sequence CurrentCorrection(Address 7806 =Side 1)

(A) [I1* to IA (3A2)], [I1 to INa (2D2)], and [JumperIA* to INa* (3A1 to 2D1)]

(B) [I1* to IB (2A2)], [I1 to INa (2D2)], and [JumperIB* to INa* (2A1 to 2D1)]

(C) [I1* to IC (1A2)], [I1 to INa (2D2)], and [JumperIC* to INa* (1A1 to 2D1)]

If the neutral CT common is towards ground(Address 1108 = Towards ground), interchange INaand INa* above.

Current INb Used for Zero Sequence CurrentCorrection(Address 7807 = Side 1)

(A) [I1* to IA (3A2)], [I1 to INb (1D2)], and [JumperIA* to INb* (3A1 to 1D1)]

(B) [I1* to IB (2A2)], [I1 to INb (1D2)], and [JumperIB* to INb* (2A1 to 1D1)]

(C) [I1* to IC (1A2)], [I1 to INb (1D2)], and [JumperIC* to INb* (1A1 to 1D1)]

If the neutral CT common is towards ground(Address 1108 = Towards ground), interchange INband INb* above.

The Source 2 current connections are the same asthe connections for Case 2. Refer to Table 9 forCase 2.

The equations for the Winding 1 I** currents are thesame for all Ydz transformers.

IA** = [IA + (1/3)IN] in per unit of INsecW1

IB** = [IB + (1/3)IN] in per unit of INsecW1

IC** = [IC + (1/3)IN] in per unit of INsecW1

where IN is the current (phasor) from the neutral CT.A current entering INa* or INb* is positive.

The winding currents are phasors! The positivedirection for a winding current in this Case 3 is intothe polarity terminals IA*, IB*, and IC* (terminals 3A1,2A1, and 1A1).

The equations for the Winding 2 I** currents are thesame as those for Case 2. See Table 10 for Case 2.

Consider again the Yd11 transformer in Figure 23(Case 2). For the A-phase-ground fault, IA = -IN = -1.0 per unit, IB = IC = 0, Ia = -Ic = 0.58 per unit, andIb = 0. Thus:

• IA** = (2/3)IA = -(2/3) per unit• IB** = -(1/3)IA = (1/3) per unit• IC** = -(1/3)IA = (1/3) per unit

• Ia** = (2)(0.577)(Ia) = (2/3) per unit• Ib** = (-0.577)(Ia) = -(1/3) per unit• Ic** = (-0.577)(Ia) = -(1/3) per unit

These are the same results as Case 2. This is to beexpected because zero sequence currentelimination and correction perform the same functionfor external faults, namely filter the zero sequencecurrents before the I** are combined. For internalfaults, the results are quite different between theelimination method and the correction method.

7UT51 v3

46 PRCM-1108A-0199

The conclusion concerning test currents for case 2also results for Case 3.

• I1 = [M X 1.5 X INsecW1] at 0°• I2 = [(M X 1.5) X (0.577 X INsecW2 )] =

[M X 0.866 X INsecW2] at 0°

The restraint current associated with the faultedphase becomes 2 X M. By adjusting M, the usercan easily control this restraint current. This allowsfor simple testing of the 87 slopes.

Three-Winding Transformers

A 7UT513 protecting three winding transformers canbe adequately tested by considering two windings ata time, and testing them like a two-windingtransformer. Test the reference winding andWinding 2. Then test the reference winding andWinding 3. These two tests will verify the 87algorithm and the constants being used to form IDIFF

and IREST. Testing Winding 2 and Winding 3 is notnecessary.

Transformers Other Than Dyz and Ydz with theabove Assumptions

If the transformer being protected has differentwinding connections or CT connections, determinethe current flows to the 7UT51 for the simplest fault,with the transformer connected to a power system inthe simplest way. If the equations for I** areavailable, they can be used in an analysis, similar tothose above, to predict the test currents needed toobtain a desired restraint current. If the equationsare not available, the metering from the WinDIGSIsoftware can be used to obtain the desired restraintcurrent. Remember always to increase the currentson different sides of the transformer by the samefactor.

Test 14. Through-Fault Security, MeteringValidation

Connect the 7UT51 using the appropriate Figure 21,22, or 24, and the accompanying notes above.Polarity connections are critical. Maintain the7UT51 connections through Test 17.

1. If Case 3 applies, Address 1107 must matchAddress 1104. Change Address 1107 ifnecessary. Keep this new setting through Test17.

2. Program Trip Relay 1 for Event 5691 87-Diffprotection: Trip . (The default setting issufficient). Keep this setting through Test 17.

3. Program LED 2 for m 5691 87-Diff protection:Trip . (This is the default setting.) Keep thissetting through Test 17.

4. For Case 1, set the source 1 current for [M XINsecW1] at 0°, where M = 1.5. For cases 2 and 3,set the Source 1 current for [M X 1.5 X INsecW1] at0°, where M = 1.5.

5. For Case 1, set the Source 2 current for [M X1.732 X INsecW2] at 0°, where M = 1.5. For cases2 and 3, set the Source 2 current for [M X 0.866X INsecW2] at 0°, where M = 1.5.

6. Momentarily apply only the Source 1 current andverify 87 tripping.

7. Momentarily apply only the Source 2 current andverify 87 tripping.

8. Reset targets.

9. Simultaneously apply both currents and verify 87does not pickup.

10. Maintain the application of currents forverification of the metering, and the next test.

To check the metering from the LCD, follow steps11-19. Text in bold are key names on the keypad.

11. Press Direct Addr , enter 4101, and pressEnter . The display will read 4101 Test Diff –Measuring?.

12. Press Yes. The display should report I1PhA=xxx , where xxx is the PhA current as apercentage of 5 amps. The value should be thetest current into terminal 3A1 divided by 5 amps.

13. Press No to page through the remainder of themetering.

7UT51 v3

PRCM-1108A-0199 47

14. Press Direct Addr , enter 4161, and press Enterto display differential values. The LCD will read4161 TEST DIF/ST – INDICATE RESULT?.

15. Press Yes. The display will report IaDiff = xxx ,where xxx is the PhA differential currentcalculated by the 7UT51. It should measure inthe neighborhood of 1.0% to 2.0%.

16. Press No to scroll through IbDiff and IcDiff .These values should be under 2.0%.

17. Continue pressing No to read the restraintvalues in percentage of the transformer rating.Based on the case and the notes above, be surethe restraint currents are as expected. Allow therestraint current percentage to vary +/- 7%. Forexample, if IaRestr and IcRestr , should equal300%, allow (293% to 307%).

18. Press Direct Addr , enter 4801, and pressEnter . The display should read 4801 Stop Test– Finish?.

19. Press Yes to end the metering tests.

To check the metering using WinDIGSI, follow steps20-32.

20. Reach dialog with the 7UT51.

21. Click Test in the Menu bar.

22. Display Commission Tests.

23. Execute 4101 Measuring and indication ofline curr. values , then click Yes.

24. The Test results will show the phase currents ofeach winding, in percentages of 5 amps.

25. Verify the percentages for the test currentsbeing applied.

26. Click Close . The Commission Tests dialog boxwill become active again.

27. Execute 4161 Indication of diff. and restr.current values , then click Yes.

28. The display will show the differential andrestraint percentages for all phases.

29. All differential values should be 3% or less.Verify the relationship and values of the restraintcurrents using the applicable notes above. The7UT51 must be responding as expected for thenext test. Allow the restraint currentpercentages to vary +/- 7%. For example, if PhA and Ph C should be about 300%, allow themto vary between (293% and 307%) beforechanging the test currents.

30. Click Close to close the Test Results dialog box.

31. Click Close to close the Commission Testswindow.

32. Select 4800 End Commission Testing , thenclick Close .

Notes about Slope 1, Slope 2, and Through-FaultRestraint Area.

Figure 25 shows the differential characteristic.Notice the differential current (IDIFF) is the absolutevalue of the vectorial sum of the currents, while therestraint current (IREST) is the sum of the absolutevalues of the currents. This fact is used in thestrategy to test the slopes and the through-faultrestraint area.

1

2

3

4

1 2 3 4 5 6 7 8 9 10 11

Non-Operate Area

Through-Fault Restraint Area( slope = 1/2 of 1606, left edge = 1618 )

Slope 1 (1606)

Slope

2 ( b

ase

point

= 1

607,

slop

e = 1

608

)

87HS Pickup(1604)

7UT51

I1 I2

5

6

7

8

Restraining Current, IREST ( in multiples of In )

Diff

eren

tial C

urre

nt, I

DIF

F (

in m

ultip

les

of I n

) I DIFF =

I REST

00

9

Operate Area

IDIFF = |I1+ I2|

IREST = |I1| + |I2|

Figure 25: Differential Characteristics

The previous test is used to simulate a through-fault.The magnitudes of the test currents are fixed tomaintain a constant IREST. The phase angle of oneof the currents is then varied to provide IDIFF. Oncethe minimum angle at which 87 trips is found, theslope is calculated.

The points of intersection of the 87 minimum pickup(Address 1603) and Slope 1, and Slope 1 and Slope2, must be known for the tests. Slope 1 goesthrough the origin. Slope 2 intersects IREST atAddress 1607.

The intersection of Address 1603 and Slope 1is thevalue of IREST at which Slope 1 begins to control 87tripping. The intersection is found using thisequation:

Address 1603-Slope 1 Intersection =

Address 1603 in per unit Address 1606

7UT51 v3

48 PRCM-1108A-0199

The intersection of Slope 1 and Slope 2 is the valueof IREST at which Slope 2 begins to control 87 tripping(Slope 2 > Slope 1). The intersection is found usingthe equation:

Slope 1-Slope 2 Intersection =

(Address 1607)X(Address 1608) in per unit(Address 1608 – Address 1606)

Assumed in the equation is Address 1608 > Address1606. The settings ranges of Slope 1, Slope 2, andthe base point of Slope 2 (Address 1607) are suchthat the lines may never intersect, or the lines maybe the same. The user should sketch the lines forSlope 1 and Slope 2 if Address 1608 ≤ Address1606, or if Address 1607 = 0.0. For any combinationof settings, at any given IREST, 87 tripping is basedon the least sensitive of: Address 1603 (minimumpickup), Slope 1, or Slope 2.

With Address 1608 > Address 1606, and Address1607 > 0.0, Test Slope 1 using a IREST between theabove two intersection points. Test Slope 2 using aIREST greater than the intersection of Slope 1 andSlope 2.

The slope tests (especially Slope 2) and thethrough-fault restraint area test may require highcurrents.

Note: Do not exceed the current limitations of the7UT51.

Test 15. Slope 1 (Lower Slope):Address 1606

In Test 14, M = 1.5 to give IREST = (2 X M) = 3.0 perunit. For most applications, IREST = 3.0 per unit fallsbetween the two intersection points discussedabove. If this is true, this test can be done now. If3.0 per unit does not fall within the intersectionpoints, then M must first be adjusted accordingly.

Continuing with the through-fault simulation (Test14):

1. Slowly increase the angle of one of the testcurrents (either one, but not both) until 87 trips.

2. Record the angle.

3. Note the operations of the contacts and LEDs.

4. Turn Off the current. Set the changed current-angle to 0°. Reset the LEDs and LCD. Keepthe test connections for the next test.

5. Calculate Slope 1 as follows:

Let θ = angle in Step 2.A = [M – (M) x (cos θ)]B = M x sin θ

Calculate [A 2 + B2]1/2 where the “1/2 power” meansthe square root of the sum.

Slope 1 = [A 2 + B2]1/2

2 x M

Expected Results:

The calculated Slope 1 should be within +/- 10% ofAddress 1606.

Contact and target operations should be the sameas Test 1, or any test with 87 tripping.

Test 16. Slope 2 (Upper Slope):Addresses 1607 and 1608

1. Select a new value of M such that IREST = 2 X Mis greater than the intersection of Slope 1 andSlope 2. Be careful not to exceed the currentlimitations of the 7UT51. Avoid (2 x M) ≥Address 1604 (87HS pickup). A value of 2.5 isusually good for M in this test.

2. For Case 1, set the Source 1 current for [M xINsecW1] at 0°. For cases 2 and 3, set the Source1 current for [M x 1.5 INsecW1] at 0°.

3. For Case 1, set the Source 2 current for [M X1.732 X INsecW2] at 0°. For cases 2 and 3, set theSource 2 current for [M X 0.866 X INsecW2] at 0°.

4. Simultaneously apply both currents and verify 87does not pickup.

5. Slowly increase the angle of one of the testcurrents (either one, but not both) until 87 trips.

6. Record the angle.

7. Note the operations of the contacts and LEDs.

8. Turn Off the current. Set the changed current-angle to 0°. Reset the LEDs and LCD.

9. Calculate Slope 2 as follows:

Let θ = angle in Step 6.A = [M – (M) x (cos θ)]B = M x sin θ

Calculate [A2 + B2]1/2 where the 1/2 powermeans the square root of the sum.

7UT51 v3

PRCM-1108A-0199 49

Slope 2 = [A 2 + B2]1/2

2 x M

Expected Results:

The calculated Slope 2 should be within +/- 10% ofAddress 1608.

Contact and target operations should be the sameas test 1, or any test with 87 tripping.

Test 17. Minimum Current for Through-FaultRestraint Area: Address 1618

Even with the minimum Address 1618, this test islikely to require high currents that exceed thecontinuous current rating of the 7UT51.Therefore, this test is optional.

If this test is performed, the current must be turnedOn and quickly turned Off – in about one second.Do not leave high currents applied, permanentdamage could occur.

To test Address 1618, a change of the setting maybe necessary to keep the test current within thelimitations of the 7UT51.

Note: Use the 7UT51 connections from Test 14,except replace the contact monitor with atimer that starts on the application or removalof test current, and stops on the closure ofthe contact from Trip Relay 1.

1. Substitute the value [0.5 X Address 1618] for Min steps 4 and 5 of Test 14.

2. Determine the higher magnitude of the two testcurrents.

3. If the calculated current in Step 2 is greater than20 amps (4 amps for a 7UT51 rated for 1 amp),change Address 1618 to 5.00.


5. Program LED 4 for “m 5651 87-Diff prot.Blocked by ext fault PhA ”, “m 5652 87-Diffprot. BLOCKED by ext fault PhB ”, and “m5653 87-Diff prot. Blocked by ext fault PhC ”.

6. For Case 1, set Source 1 current for [(0.5 XAddress 1618) X INsecW1] at 0°. For cases 2 and3, set Source 1 current for [(0.5 X Address 1618)X 1.5 X INsecW1] at 0°.

7. For Case 1, set Source 2 current for [(0.5 XAddress 1618) X 1.732 X INsecW2] at 0°. Forcases 2 and 3, set Source 2 current for [(0.5 XAddress 1618) X 0.866 X INsecW2] at 0°.

8. Set the timer to start on the application of thecurrent with the lower magnitude, and stop onthe closure of the contact from Trip Relay 1.

9. Turn On only the current with the lowermagnitude.

10. Turn Off the current and record the tripping timeof 87 plus contact.

11. Repeat steps 9 and 10 to obtain a pickuptimespread of 87 plus contact.

12. Temporarily disconnect the timer.

13. If either currents of Source 1 or Source 2 exceed20 amps (4 amps for a 7UT51 rated for 1 amp),the application of the currents in the next stepmust be very brief (about 1 second).


15. Turn Off both currents.

16. Note the state of LED 4, and reset if necessary.If LED 4 is lit, the pickup for the through-fault-restraint area was met or exceeded.

17. Based on the state of LED 4 from Step 16,adjust the currents up or down while they areOff , and repeat steps 14-16 until the pickuppoint is found for Address 1618. Both currentsmust be adjusted by the same factor. This iscritical. Try factors such as 102%, 101%, 99%,98%.

18. Record the currents at pickup from Step 17.

19. Set both Source 1 current and Source 2 currentfor 110% to 120% of the values in Step 18.

20. Re-connect the timer.

21. Set the timer to start when the current with thehigher magnitude is turned Off , and stop whenthe contact from Trip Relay 1 closes.

22. The current source providing more than 20amps (4 amps) should be on only briefly (about1 second) in the next step.


24. Turn Off the higher magnitude current only.

25. Turn Off the lower current.

26. Be sure LED 4 is lit. If not, repeat steps 19-25with slightly higher currents.

27. Record the value from the timer.

28. Record the LEDs and LCD, and reset them.

7UT51 v3

50 PRCM-1108A-0199

29. Set Addresses 1618 and 1625 to the originalvalues.

30. Program LED 4 for the original settings.

Expected Results:

The result of Step 17 is the tested value for Address1618. To calculate the tested value:

Case 1:Source 1 Current + Source 2 Current INsecW1 1.732 X INsecW2

(in. per unit )

Case 2 or 3:Source 1 Current + Source2 Current 1.5 X INsecW1 0.866 X INsecW2

(in. per unit )

The result should be within +/- 5% of Address 1618.Steps 23-27 are a simulation of a close-in externalfault followed by an internal fault which maps ontothe IDIFF = IREST line in Figure 25. Since the internalfault maps to this line, Address 1617 (discussedbelow) is bypassed. Extra delay of 87 tripping isadded because the through-fault restraint picked upbefore the fault. This extra delay of about 2 cyclesshould be present in step 27. Subtract the trippingtimes of 87 in Step 11 from the time in Step 27. Theresult should equal 33.3 ms +/- 17 ms. The trippingtimespread of 87 and contact in Step 11 must beconsidered, though the spread should be tightbecause of the substantial fault current.Contact and target operation for Step 11 should bethe same as for any 87 tripping: all trip contactsshould close, Signal Relays 1 and 2 should operate,and LEDs 1 and 2 should light. The LCD shoulddisplay 87 Diff GenFlt and 87DiffGenTrip .

For Step 16, no contacts should operate, but theLCD should display 87Diff GenFlt . LED 4 shouldlatch on when the through-fault restraint is picked-up.

The steps leading to Step 27 must be done quickly;therefore, contact operation should not be checked.At Step 27, the LEDs and LCD should be consistentwith Step 11, except LED 4 should be lit in addition.

Program Trip Relay 1, LED 2, and Address 1107 forthe Original Settings

Through-Fault Restraint Area Slope andMaximum Duration of Through-Fault CT-Saturation Restraint: Address 1617

Testing the slope associated with the through-faultrestraint area (Figure 25) is not recommended.Such a test would likely result in the currentlimitations of the 7UT51 being exceeded because ofthe time that would be needed to find the slope lineof the area, by varying current phase angle, whilehigh currents would be applied.

Manual testing of the maximum duration of through-fault restraint is very complicated; therefore, a testfor Address 1617 is not included. The feature canbe tested with automated-test equipment. Adescription of one possible automated-test is givenin the next paragraph for users wishing to testAddress 1617.

Program an LED, with memory, for events 5651,5652, and 5653. The LED will indicate pickup of thethrough-fault restraint. Program a trip relay for 5691,87 tripping. Connect the 7UT51 as in test 17. Setup a fault which maps above either Slope 1 or Slope2, but not within [85% to 100%] of the IDIFF = IREST

line or above 87HS pickup. The fault currentsshould be within the continuous current rating of the7UT51. Set a timer to start on the application of thefault, and stop on the closure of the trip contact.Apply the fault, and record the tripping time of 87.Repeat the fault a couple of times to obtain a rangeof tripping times of 87 for the specific fault. Then,set-up a two-stage fault event. For Stage 1,simulate a through-fault that maps into the through-fault restraint area. Set the currents for about 120%of the minimum values needed to enter the through-fault restraint area (120% of the results from Test17). This ensures the through-fault restraint will pickup. The duration of Stage 1 should be 2 cycles ormore. The only concern for the Stage 1 duration isthe current limits of the 7UT51. Stage 2 is theaforementioned fault. Set the timer to start at thebeginning of stage 2, and stop when the trip contactcloses. The duration of Stage 2 should be Address1617 plus 10 cycles. Apply the event. Be sure theLED lights. Record the tripping time of 87.

Address 1617 is the setting of a timer that is armedwhen the through-fault restraint picks up. The timerbegins to expire when the differential operating pointleaves the through-fault restraint area. Tripping of87 is inhibited until the timer expires.

The tripping time of 87, determined before the two-stage event, must be subtracted from the trippingtime recorded during the event, to obtain the tested

7UT51 v3

PRCM-1108A-0199 51

value for Address 1617. The accuracy of Address1617 is +/- 1.02 cycles (timer accuracy included).The pickup timespread of 87 must be considered.

Test 18. Status Control - Differential Elements:Discrete Inputs, Address 1601

If the operational status of the differential protectionis controlled by a discrete input(s), the tests abovecan be used, with the input in the opposite state, toverify the control is functioning. Also, if multiple setsof protection settings are used, and Address 1601 isOff or Block Tripping in any of these sets, the testsabove can be used to verify proper operation of thedifferential protection.

Most of the events in a 7UT51 pertaining to thedifferential protection are associated with 87 and87HS. The check of the control of 87 and 87HS canbe done with one test, in which enough current isinjected to pickup both 87 and 87HS. Steps 1-8 ofTest 6, with 87 tripping enabled (Address 1625 notequal to infinity) and the timer eliminated (times arenot important in checking the basic control of theinputs), would be sufficient. Alternatively, the usercould use other tests above, or new tests, to checkthe control.

A smaller number of the events pertaining to thedifferential protection involve harmonic restraint andthe through-fault restraint area. Variations of theabove tests, or new tests, can be run to check thecontrol.

Expected Results:

Address 1601 = Off and an input causing the“coming” of Event 5603 >87 – Block DifferentialProtection - before the differential protection hasoperated – should have similar effects. Eithershould effectively render the differential protectionnon-existent. Events associated with the differentialprotection should be prevented from driving contactsor LEDs. The LCD should not indicate anydifferential operation.

With the exception of the six events associated withharmonic and through-fault restraint, the differentialevents should not be affected by Event 5603 if thelatter occurs after the former is activated. Forexample, if events associated with 87 are driving tripcontacts, signal contacts, and LEDs, and then Event5603 is applied, the contacts and LEDs should

remain operated. Event 5603 should, in a sense, beignored.The events associated with harmonic restraint areevents 5641-5643. Events 5651-5653 apply tothrough-fault restraint. They are described below.Event 5631 (also covered below) is usually activewhen any of the restraint events are occurring. IfEvent 5603 occurs after the restraint events andEvent 5631 is activated, the latter should be blockedwhen the former occurs. Tripping should not thenresult because the restraint should prevent trippingbefore Event 5603, and Event 5603 should preventtripping thereafter.

If Event 5631 is active during 87 or 87HS tripping,and then Event 5603 occurs, Event 5631 shouldremain active. The event should only go away if thedifferential protection is restrained before Event5603 occurs.

If Event 5603 is applied first, and then a fault ortransformer inrush is simulated, the differentialfeatures should be blocked as mentioned. However,if Event 5603 is removed while the fault or inrush isstill present, the differential protection should thenoperate as normal. In other words, all of the eventsassociated with the differential protection should befree to operate trip relays, signal relays, and LEDs.

If tripping results before Event 5603 occurs, or ifEvent 5603 is released and then tripping occurs, theLCD should display 87Diff GenFlt and87DiffGenTrip .

Address 1601 = Block Tripping and Event 5605 >87–Blk Differential Prot Trip Signal – if appliedbefore a differential operation – should have similareffects. Either should prevent events 5671-5674,5691, and 5692 (described below) from operatingtrip relays. Also, Event 0511 General Trip of theRelay should not occur from the differentialprotection. However, events 5621, 5622, and 5631(described below) should be capable of operatingtrip contacts. All of the events below should be freeto operate signal relays or LEDs.

• 5621 87–Differential unit pickup• 5622 87–HS Diff prot unit picked-up• 5631 87–Diff prot: General fault detection• 5641 87–Diff prot: BLOCKED by harmonics PhA• 5642 87–Diff prot: BLOCKED by harmonics PhB• 5643 87–Diff prot: BLOCKED by harmonics PhC• 5651 87–Diff prot: BLOCKED by ext fault PhA• 5652 87–Diff prot: BLOCKED by ext fault PhB• 5653 87–Diff prot: BLOCKED by ext fault PhC

7UT51 v3

52 PRCM-1108A-0199

• 5671 87–Diff protection: General trip• 5672 87–Diff protection: Trip PhA• 5673 87–Diff protection: Trip PhB• 5674 87–Diff protection: Trip PhC• 5681 87–Diff protection: PhA (w/o Time dly)• 5682 87–Diff protection: PhB (w/o Time dly)• 5683 87–Diff protection: PhC (w/o Time dly)• 5684 87HS–Diff protect: PhA (w/o Time dly)• 5685 87HS–Diff protect: PhB (w/o Time dly)• 5686 87HS–Diff protect: PhC (w/o Time dly)• 5691 87 –Diff protection: Trip• 5692 87HS –Diff protection: Trip

If any of the above events are active before Event5605 occurs, they should continue to operate tripcontacts, signal contacts, and LEDs, after Event5605. Event 5605 should essentially be ignored.If (1) Event 5605 is first activated, (2) a fault orrestraint condition is applied, and then (3) Event5605 is de-activated while Stage 2 is still applied,events 5671-5674, 5691, and 5692 should remainblocked from operating trip contacts. The eventsshould continue to operate signal relays and LEDs.All other events above should be unaffected byEvent 5605.

The LCD should display 87Diff GenFlt when Event5605 is applied before the fault. The same displayshould result if Event 5605 is applied before thefault, and is then de-activated while the fault is stillpresent. The LCD should be unchanged if Event5605 occurs after the fault.

7UT51 v3

PRCM-1108A-0199 53

Thermal Overload Protection(49-1 and 49-2)

The two thermal overload protective elements (49-1and 49-2) are independent.

Address 7824 determines the winding or virtualobject that 49-1 protects. If Address 7824 isDISABLED, 49-1 is non-existent. Address 2401determines the status of 49-1. The element isoperational for any Address 2401 except Off .

Address 7825 determines the winding or virtualobject that 49-2 protects. If Address 7825 isDISABLED, 49-2 is Non-Existent. Address 2501determines the status of 49-2. The element isoperational for any Address 2501 except Off .

Notes about Testing 49-1 and 49-2

Testing of 49-1 and 49-2 may cause operations of87, 87HS, 50/51, and 50HS. If this occurs,Addresses 1601 and 2101 can be set to OFF todisable the differential elements and backupovercurrent elements. After testing 49-1 and 49-2,these addresses must be reset to the desiredvalues.

Address 2406 is important for testing 49-1. IfAddress 2406 = Average \T , this procedure requiresthat a single current source be connected to injectcurrent in all three phases associated with thewinding or object. If Address 2406 = [Theta MAX]or [\T @ Imax] , then current injection into any onephase is sufficient.

The same comments for Address 2406 apply toAddress 2506, which is associated with 49-2.

The same 7UT51 connections can be used for all ofthe 49 tests. Figure 26 shows the connections forthe following example. Element 49-1 is protectingWinding 1 using either the maximum calculatedtemperature for each phase current (Address 2406 =Theta MAX ) or the calculated temperature based onthe highest phase current (Address 2406 = \T @Imax ). Element 49-2 is protecting Winding 2 usingthe average of the calculated temperatures of thephases.

For the example, this procedure requires current beinjected in all three phases of Winding 2 to test 49-2.Current injection for Winding 1 can be either single-phase or include all three phases (single-phase isshown for simplicity).

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1ContactMonitor

SignalContact 1

W149-1

W249-2

W3(7UT513only)

I1

or

Start I1On

Stop

Timer

Example

Connections

Only

SignalContact 2

TripContact 1

8B17B1

8B27B2

5B15B2

Figure 26: Test Connections for Testing 49-1and 49-2

First identify the applicable winding for currentinjection. Then, based on Address 2406 or Address2506, connect the winding phases for either single-phase or three phase current injection.

Settings for Trip Relays, Signal Relays, andLEDs for All 49 Tests

Apply these settings now. If only one 49 is beingtested, the events for the other element are notneeded.

LED 2 = nm 1571 49-TRIP by thermal O/Lprotection 1 (nm means no memory)= nm 1621 49-TRIP by thermal O/Lprotection 2 (nm means no memory)

LED 3 = nm 1566 49-Thermal O/L prot.1: Thermalwarning= nm 1616 49-Thermal O/L prot.2: Thermalwarning

LED 4 = nm 1565 49-Thermal O/L prot.1: Currentwarning= nm 1615 49-Thermal O/L prot.2: Currentwarning

7UT51 v3

54 PRCM-1108A-0199

Signal Relay 1 = 1565 49-Thermal O/L prot.1:Current warning= 1615 49-Thermal O/L prot.2: Current warning

Signal Relay 2 = 1566 49-Thermal O/L prot.1:Thermal warning = 1616 49-Thermal O/L prot.2:Thermal warning

Trip Relay 1 = 1571 49-TRIP by thermal O/Lprotection 1 = 1621 49-TRIP by thermal O/Lprotection 2

Test 19. Warning, Overload Current: Address2405 (49-1) and 2505 (49-2)

Connect the 7UT51 using the example and theaccompanying Figure 26. The timer is not neededfor this test.

49-1 Current Warning:

1. The alarm should occur near

[Address 2405 X INsecWx ]

or

[Address 2405 X IObjsec].

Slowly increase the current until LED 4 lightsand the contact of Signal Relay 1 closes.Record the current.

2. Slowly decrease the current until LED 4 goesout and the Signal Relay 1 contact opens.Record the current.

3. Turn Off the current, note the LCD display, andreset the targets.

49-2 Current Warning:

Follow steps 1-3 using Address 2505 in Step 1.

Expected Results:

The 49-1 current warning should occur within +/-3% of [Address 2405 X INsecWx] or [Address 2405 XIObjsec]. This applies for 49-2 also, using Address2505.

The 49 warning should dropout at a current between[95% and 99%] of the actual current at pickup.

For the default settings and the changes made,LED 4 should light and the contact of Signal Relay 1should close when the 49 current warning occurs.At dropout, the LED should go out and the contact

open. The LCD should not give an indication of theevent.

Notes about 49 Trip Times and Alarm Times

The tests below require that there be no preloadbefore 49 temperature warnings and 49 tripping aretested. aWithout preload, the trip time of 49 iscalculated as such:

Let a1 = Address 2402 X I NsecWx OR I1

Address 2402 X I Objsec (for 49-1) I1

Let a2 = Address 2502 X I NsecWx ORI1

Address 2502 X I Objsec (for 49-2) I1

where I1 is the test current (Figure 26)

“a1” and “a2” must be less than 1 (I1 > Address X Irated)

49-1 Ttrip =Address 2403 X ln [1 – (a1)2 ]

49-2 Ttrip =Address 2503 X in [1 – (a2)2 ]

where ln is the natural log.

The natural log will be negative for a < 1. Ignore thisby taking the absolute value of the number, thenmultiplying by Address 2403 or 2503.

Note : Address 2403 and 2503 are in minutes.

The time for a 49 warning based on temperature riseis calculated as such (no preload):

49-1 Twarn =Address 2403 X ln [1 – {Address 2404in decimal formatX(a1)

2 }]

49-1 Twarn ≈ 49-1 Ttrip X Address 2404 in decimalformat

49-2 Twarn= Address 2503 X ln [1 – {Address 2504in decimal formatX(a2)

2 }]

49-2 Twarn ≈ 49-2 Ttrip X Address 2504 in decimalformat

For any group of 49 settings, the trip time decreasesas the test current increases. The maximum test

7UT51 v3

PRCM-1108A-0199 55

current for the tests below is 20 amps (4 amps for a7UT51 rated for 1 amp). Using this current,calculate 49 Ttrip now. Also estimate 49 Twarn.

Testing the 49 elements with the desired, in-servicesettings is strongly recommended. However, ifthose settings would result in unpractical warningand trip times, decrease Address 2403 or 2503. Therecommended minimum 49 warning time – if settingchanges are made – is about two minutes, giving atrip time of [two-three] minutes. If the desiredsettings result in warning times faster than twominutes, do not change the settings.

The 7UT51 continually calculates the temperaturerise of the winding or object. Therefore, prior testingor loading of the 7UT51 will make the test resultsbelow unpredictable unless the temperature rise isforced to zero. Changing Address 2401 (2501) toOff , waiting at least one minute, and then resettingAddress 2401 (2501) to the desired settingaccomplish this.

Note: These steps must be done before, andbetween, all tests for 49 warning times and49 trip times.

Test 20. Warning, Temperature: Addresses 2404,2403 and 2402 (49-1) ; Addresses 2504, 2503, and2502 (49-2)

Connect the 7UT51 using the example and theaccompanying Figure 26. The timer is used with theSignal Relay 2 contact in this test.

49-1 Temperature Warning:

1. Set Address 2401 = Off . Wait at least oneminute with this setting. Set up the test duringthe wait.

2. Any Source 1 current magnitude between {[1.2X Address 2402 X INsecWx] or [1.2 X Address2402 X IObjsec]} and 20 amps (4 amps) can beused. The alarm time decreases as the currentincreases. The following is recommended. If49-1Twarn < 2 minutes for a current of 20 amps (4amps), lower the current to get a warning time ofabout 2 minutes. Otherwise, use a currentmagnitude of 20 amps (4 amps).

3. Set the timer to start on the application ofcurrent, and stop on the closure of the SignalRelay 2 contact.


5. Apply the current.

6. Observe the LEDs and the Signal Relay 1contact during the tests.

7. Turn off the current after the alarm but beforethe trip. If the trip occurs, there is no problem.Turning Off the current before the trip savestime in reading the LCD.


9. Record the LEDs and LCD, and reset.

10. Follow Step 1 if any other testing is done.

49-2 Temperature Warning

Follow steps 1-10 for 49-1, except use Address2501 in steps 1 and 4, Address 2502 in Step 2, and49-2 Twarn in Step 2.

Expected Results

The warning alarm should occur within the larger of+/- 12% or +/- 2 seconds of the calculated 49 Twarn.

With the default settings and the changes made,LED 4 should light and the contact of Signal Relay 1should close several seconds after the application ofcurrent (the actual time is not important). When thetemperature warning occurs, LED 3 and SignalRelay 2 should operate. If 49 does not trip, no othertarget or contact operations should occur. The LCDshould show 49 O/L1 PU Θ or 49 O/L2 PU Θ. LED3 and Signal Relay 2 should not reset immediatelyafter the current is Off . The 7UT51 will calculate thetemperature as still being above the alarm point,until a cool-down period occurs.

7UT51 v3

56 PRCM-1108A-0199

Test 21. 49 Tripping: Addresses 2402 and2403 (49-1), 2502 and 2503 (49-2)

• Perform this test for 49-1 only if Address 2401 =On.

• Perform this test for 49-2 only if Address 2501 =On.

Connect the 7UT51 using the example and theaccompanying Figure 26. Connect the contact ofTrip Relay 1 to the timer.

49-1 Tripping

1. Set Address 2401 = Off . Wait at least oneminute with this setting. Set up the test duringthe wait.

2. If Test 20 was done, use the same Source 1current. Otherwise, any Source 1 currentmagnitude between {[1.2 X Address 2402 XINsecWx ] or [1.2 X Address 2402 X IObjsec]} and 20amps (4 amps) can be used. The trip timedecreases as current increases. The followingis recommended. If 49-1 Ttrip < two minutes fora current of 20 amps (4 amps), lower the currentto get a trip time of about two minutes. If 49-1Ttrip > two minutes for a current of 20 amps (4amps), use this maximum current.

3. Set the timer to start on the application ofcurrent, and stop on the closure of the TripRelay 1 contact.

4. Set Address 2401 = On.


6. Observe the LEDs and the Signal Relay 1contact during the test.

7. Turn Off the current, after a trip, as soon aspractical. This will save time in reading the LCD.


9. Record the LEDs. Wait for the LCD and record.Reset.

10. Follow Step 1 if any other testing is done.

49-2 Tripping

Follow steps 1-10 for 49-1 tripping except useAddress 2501 in steps 1 and 4, Address 2502 inStep 2, and 49-2 Ttrip in Step 2.

Expected Results

The trip time should occur within the larger of +/-12% or +/- 2 seconds of the calculated 49-1 Ttrip

or 49-2 Ttrip.

After several seconds of the current application (theactual time is not important), LED 4 should light andthe contact of Signal Relay 1 should close. Thewarning should occur at about the same time as intest 20 if the same test current is used. LED 3 andSignal Relay 2 should operate. At tripping, with thedefault settings and the changes made, all of the tripcontacts should close, contacts of Signal Relays 1,2, 6 and 7 should be toggled, and LEDs 1, 2, 3, 4,and 9 (49-1) or 10 (49-2) should be lit. When thecurrent is turned Off , the contact of Signal Relay 1should open and LED 4 should go out. After sometime – perhaps minutes – the trip contacts shouldopen, Signal Relay 6 should reset, and LED 2should go out (the 7UT51 is still calculatingtemperature with the current off). Later, LED 3should go out and Signal Relays 2 and 7 shouldreset. The other LEDs have memory. The LCDshould display 49 O/L1 PU Θ and 49 O/L1 TRIP, or49 O/L2 PU Θ and 49 O/L2 TRIP, after LED 2 goesout (49 trip resets).

Test 22. Status Control of 49 Elements:Discrete Inputs or Addresses 2401and 2501

If the operational status of a 49 element is controlledby a discrete input(s), Test 21 can be done twice,with the input state changed between the two tests,to verify the control is functioning. Also, if multiplesets of protection settings are used, and in any ofthose sets Address 2401 or Address 2501 has asetting other than one that has already been tested,Test 21 can done to verify proper operation of the 49elements.

For this Test 22, ignore the conditional statements atthe beginning of test 21 concerning Addresses 2401and 2501. Test 21 is the most comprehensive testin this section; therefore, the test is the best one toperform to check status control.

Expected Results:

Address 2401 = Off and an input causing thecoming of Event 1553 >49-BLOCK thermal O/LProtection 1 should have similar effects. Eithershould effectively render 49-1 non-existent.

7UT51 v3

PRCM-1108A-0199 57

If Event 1553 is initially blocking 49-1, and then theinput state is changed while current is still presentabove [Address 2402 X INsecWx (or IObjsec)], 49-1should begin to time-out at the instant of the inputtransition. The element should trip if the current ispresent long enough, but the trip time may not bewithin the specifications given for Test 21. The triptime from input transition may be longer than thespecification.

If Event 1553 occurs while 49-1 is timing out, but nottripped, the element should be immediately blockedat the event occurrence. Any LEDs or signal relaysthat operate before the event should immediatelyreset when the event occurs. The coming of Event1553 after a 49-1 trip should do nothing initially. The7UT51 should remain in a trip state until 49-1tripping drops out. Then the event should cause theimmediate going of Event 1566 (thermal warning –LED 3). Without Event 1553, Event 1566 would stayactive for a long time until the calculatedtemperature fell below 99% of the thermal alarmpickup value.

Address 2501 = Off and an input causing thecoming of Event 1603 >49-BLOCK thermal O/Lprotection 2 should have similar effects. Eithershould effectively render 49-2 non-existent. Theaction described in the two paragraphs immediatelyabove should apply for Event 1603 and 49-2.

Address 2401 = Block Tripping and an inputcausing the coming of Event 1555 >49-BLOCK tripof thermal O/L prot 1 , before a 49-1 trip, shouldhave similar effects. Either should prevent Event1571 from operating trip relays. All of the 49-1events (including Event 1571) should be uninhibitedin operating LEDs and Signal Relays. The LCDshould show 49 O/L1 PU Θ after the going of Event1571 (LED 2).

If Event 1555 blocks 49-1 tripping, and then theinput changes to cause the going of Event 1555while the calculated temperature is still above thetrip threshold (LED 2 is lit), the trip relays shouldremain blocked. The LCD should display 49 O/L1PU Θ after LED 2 goes out.

Applying Event 1555 while 49-1 is timing out, but nottripped, should have the same effect as applying theevent before 49-1 begins to time out.

Applying Event 1555 after 49-1 has tripped shoulddo nothing. The 7UT51 should remain in a trip state.

The LCD should read 49 O/L1 PU Θ and 49 O/L1TRIP.

Address 2501 = Block Tripping and an input causingthe coming of Event 1605 >49-BLOCK trip ofthermal O/L prot.2 , before a 49-2 trip, should havesimilar effects. Either should prevent Event 1621from operating trip relays. All of the 49-2 events(including Event 1621) should be uninhibited inoperating LEDs and signal relays. The LCD shouldshow 49 O/L2 PU Θ after the going of Event 1621(LED 2). The action described in the threeparagraphs immediately above should apply forevents 1605 and 49-2.

Address 2401 = Alarm Only and an input causingthe coming of Event 1554 >49-Event only fromthermal O/L prot. 1 , before a 49-1 trip, should havesimilar effects. Either should prevent Event 1571from operating trip relays, signal relays, or LEDs. Allother events associated with 49-1 should be free tooperate LEDs and signal relays.

If Event 1554 prevents Event 1571 from operating,and then the input for Event 1554 is changed whilethe calculated temperature is above the tripthreshold (as indicated by Event 1567 49-ThermO/L prot.1: Pickup ), Event 1571 should still remainblocked from operating trip contacts, signal contacts,and LEDs.

Applying Event 1554 while 49-1 is timing out, but nottripped, should have the same effect as applying theevent before 49-1 begins to time out.

Applying Event 1554 after 49-1 has tripped shoulddo nothing. The 7UT51 should remain in a trippedstate.

Address 2501 = Alarm Only and an input causingthe coming of Event 1604 >49-Event only fromthermal O/L prot. 2 , before a 49-2 trip, should havesimilar effects. Either should prevent Event 1621from operating trip relays, signal relays, or LEDs. Allother events associated with 49-2 should be free tooperate LEDs and signal relays. The actiondescribed in the three paragraphs immediatelyabove should apply for Event 1604 and 49-2. (Event1617 49-Therm O/L prot.2: Pickup indicates thetemperature is above the trip threshold.)

7UT51 v3

58 PRCM-1108A-0199

Reset 7UT51 for Desired Settings

Program Trip Relay 1, Signal Relays 1 and 2, andLED 2, 3, and 4 for the desired settings. If 49warning or trip times were decreased for testingpurposes, reset Addresses 2403 and 2503 to theoriginal settings. Be sure Addresses 2401 and 2501have the proper settings. Reset any otheraddresses changed for testing purposes.

External Trip Functions(External trips 1 and 2) andOther Discrete Input Functions

These two External Trip functions are independent.The existence of External Trip Function 1 isdetermined by Address 7830. The status of thefunction is determined by Address 3001. Thefunction is operational when Address 7830 =Existent and Address 3001 is any setting other thanOff . A discrete input must be programmed for Event4526 >External Trip 1 .

The existence of External Trip Function 2 isdetermined by Address 7831. The status of thefunction is determined by Address 3101. Thefunction is operational when Address 7831 =Existent and Address 3101 is any setting other thanOff . A discrete input must be programmed for Event4546 >External Trip 2 .

Optional Programming for all External TripFunction Tests

The settings needed for each test are given in thesteps of the test. The settings in this part are notrequired, but they allow for a more complete checkof the External Trip functions. Enter these settingsnow if operations of LEDs and signal relays, by theExternal Trip functions, are desired.

If only one External Trip function is to be tested, donot include the events for the other function.

Signal Relay 1 = LED 2= 4537 External trip 1: GeneralTRIP(no memory for LED)= 4557 External trip 2: GeneralTRIP(nm for LED)

Signal Relay 2 = LED 3= 4536 External Trip 1: General faultdetect(nm for LED)= 4556 External Trip 2: General faultdetect(nm for LED)

Signal Relay 3 = LED 4= 4526 External trip 1(nm for LED)= 4546 External trip 2(nm for LED)

7UT51 Test Connections – All External TripFunction Tests

Trip

Contact

Outputs

3D1

3B1

3A15B1

5A1

6D1

5D1

5B2

5A2

6D2

5D2

5B3

5A3

6D3

5D3

4D1

4D3

4C1

4C2

7D3

6B1

6B2

6B3

6B4

6A2

3C3

5B4

5A4

6D4

5D4

4D2

4D4

3C1

4C4

7D4

7B1

7B2

7B3

7B4

6A3

3C4

4A2

4A3

4A4

8B1

8B2

8B3

8B4

6A1

3C2

2C1

2B1

2A1

1C1

1B1

1A1

3D2

3B2

3A2

2C2

2B2

2A2

1C2

1B2

1A2

4A1

4A1

4A2

Fiber Optic

RS-232 Wire

Ia'

Ia

IA

Ib'

Ib

IB

Ic'

Ic

IC

2D12D2I

Na1D11D2I

Nb

Current

Inputs

Communications In

Communications Out

S4

S3

S2

S1

RelayStatusOutputs

S6

S7

S8

S9

S10

S11

SignalContactOutputs

Or

F-SMARX

F-SMATX

TXRX

GndGnd

7UT513

8A2

8A4

8D2

8D4

7D2

4B1

8A1

8A3

8D1

8D3

7D1

4B2

Gnd

DCDC

+

+

+

+

+

+

-

-

-

-

-

-

T1

T2

T3

PowerSupply

D1

D2

D3

D4

D5

Switch

Discrete

Inputs

S5

ContactMonitor

Stop

Start

Timer

Figure 27: Tests 23 – 25 Connection Diagram

Figure 27 shows the connections of the 7UT51 fortests 23-25. Observe polarity for the connections.

The contact monitor is used first to check contacts.The timer is used later. Instructions are given in thetests as to when the timer should be turned On.

7UT51 v3

PRCM-1108A-0199 59

Test 23. External Trips, Function Testand Trip-Time Delay: Addresses 3002 (Trip 1)and 3102 (Trip 2)

Perform this test for External Trip Function 1 only ifAddress 3001 = On and an input is programmed forEvent 4526 >External Trip 1 .

Perform this test for External Trip Function 2 only ifAddress 3101 = On and an input is programmed forEvent 4546 >External Trip 2.

Connect the 7UT51 as shown in Figure 27. Startwith the sensor monitoring the contact of TripRelay 1. The timer is turned on later in the test.

External Trip Function 1:

1. Program Discrete Input 1 for Event 4526>External Trip 1 act.HI. The event can be setfor act.LO as well. Event 4537 External Trip 1:General TRIP.

2. If Address 3002 is not 0.00 seconds , programTrip Relay 2 for Event 4536 External Trip 1:General Fault Detect . Otherwise, disregardthis step.

3. Monitor a contact of Trip Relay 1 with anohmmeter or sensor.

4. Apply (or remove) DC voltage to Input 1 toactivate Event 4526.

5. Note the response of the trip contacts, signalcontacts, and LEDs.

6. Remove (or apply) the DC from Input 1.

7. Note the response of the trip contacts, signalcontacts, LEDs, and LCD.

8. If Address 3002 = 0.00 seconds , reset thetargets, and end the test. Otherwise, continue.

9. Turn on the timer. Set the timer to start on theclosure of the contact of Trip Relay 2, and stopon the closure of the contact of Trip Relay 1.

10. Apply (or remove) DC voltage to Input 1.


12. Remove (or apply) DC voltage from Input 1.

13. Reset LEDs and LCD.

External Trip Function 2:

Follow steps 1-14 for External Trip Function 1,except use:• Event 4546 >External trip 2 act.HI in steps 1

and 5.• Event 4557 External trip 2: General T RIP in

Step 2.• Event 4556 External trip 2: General Fault

Detect in Step 3.• Address 3102 in steps 3 and 9.

Expected Results:

The optional programming is assumed below.

The result of Step 5 should be the operation of TripRelay 1 (and 2 if programmed), signal relays 1-3,and LEDs 1-4. LED 1 should light because of thedefault setting, Event 0511 General trip of therelay . Depending on Address 3002 (3102), thedelay between the input and tripping may benoticeable. When the input is changed in Step 7,the contacts and LEDs should reset, except forLED 1, which has memory. The LCD should readExt1 Gen.Flt and Ext1 Gen.TRIP or Ext2 Gen.Fltand Ext2 Gen.Trip .

The value from the timer in Step 12 is the direct,tested value of Address 3002 or Address 3102. Thetested value should be within the larger of +/- 3% or+/- 13 ms of Address 3002 or Address 3102. Thetimer should not stop if the address being tested hasa value of infinite seconds (+*).

The effects of Address 3002 and Address 3102 canbe seen using the Network Disturbances option inthe WinDIGSI software. Obtain dialog with the7UT51. Click on Annunciation , thenAnnunciations Edit . Select NetworkDisturbances , and Display . Display an eventassociated with the testing. Subtract the time forEvent 4536 (4556) from the time for Event 4537(4557) to get the delay caused by Address 3002(3102).

The same contacts and LEDs that operate in step 5should operate in Step 11. The LCD in Step 13should be the same as well. The only exception is ifAddress 3002 or Address 3102 equals infiniteseconds. In this case, Trip Relay 1, Signal Relay 1,and LEDs 1 and 2 should not operate. The LCDshould read Ext1 Gen.Flt or Ext2 Gen.Flt .

7UT51 v3

60 PRCM-1108A-0199

Test 24. Status Control of External Trips:Discrete Inputs, Address 3001 (Trip 1)and Address 3101 (Trip 2)

If the operational status of either External Tripfunction can be controlled by a discrete input, Test23 can be done twice, with the input state changedbetween tests, to verify the control is functioning.Also, if multiple sets of protection settings are used,and Address 3001 or Address 3101 is Off or BlockTripping in any of these sets, Test 23 can be donewith these settings to verify proper operation of theExternal Trip functions. (Disregard the conditionalstatements given at the beginning of Test 23.)

Expected Results:

Address 3001 = Off and an input causing thecoming of Event 4523 >BLOCK External Trip 1should have similar effects. Either should effectivelymake External Trip Function 1 non-existent. Event4526 (which provides the status of the inputprogrammed to the event) should be free to operateLEDs or signal relays, but the LCD should not showany indication of External Trip Function 1operations (default settings).

If Event 4523 is blocking External Trip Function 1 ,and then the event is released while the ExternalTrip is still applied, all events associated withExternal Trip Function 1 should be free to operatetrip relays, signal relays, and LEDs. The LCDshould show Ext1 GenFlt and Ext1 Gen.TRIP .

Applying Event 4523 after External Trip Function 1has tripped should do nothing. The event should beessentially ignored. The 7UT51 should remain in atripped state.

Address 3101 = Off and an input causing thecoming of Event 4543 >BLOCK External Trip 2should have similar effects. Either should effectivelymake External Trip Function 2 non-existent. Event4546 (which provides the status of the inputprogrammed to the event) should be free to operateLEDs or signal relays, but the LCD should not showany indication of External Trip Function 2operations. The two paragraphs immediately aboveshould also apply to Event 4543 and External TripFunction 2.

Address 3001 = Block Tripping and an inputcausing the coming of Event 4525 >BLOCK tripsignal of External Trip 1 , applied before anExternal Trip Function 1 trip occurs, should havesimilar effects. Either should block Event 4537 fromoperating trip relays. Event 4536 should be free tooperate trip relays, and all events of External TripFunction 1 (including Event 4537) should beuninhibited in operating signal relays and LEDs.The LCD should read Ext1 Gen.Flt after the inputfor External Trip Function 1 is removed.

If Event 4525 is blocking Event 4537, and thenEvent 4525 is removed while the input for ExternalTrip Function 1 is still applied, Event 4537 shouldremain blocked from operating trip contacts. TheLCD should show Ext1 Gen.Flt .

Applying Event 4525 after External Trip Function 1has tripped should do nothing. The event should beignored.

Address 3101 = Block Tripping and an inputcausing the coming of Event 4545 >BLOCK tripsignal of External Trip 2 , applied before anExternal Trip Function 2 trip occurs, should havesimilar effects. Either should block Event 4557 fromoperating trip relays. Event 4556 should be free tooperate trip relays, and all events of External TripFunction 2 (including Event 4557) should beuninhibited in operating signal relays and LEDs.The LCD should read Ext2 Gen.Flt after the inputfor External Trip Function 2 is removed. The twoparagraphs immediately above should also apply toEvent 4545 and External Trip Function 2.

7UT51 v3

PRCM-1108A-0199 61

Test 25. Trip Dropout-Time of External Trips:Addresses 3003 (Trip 1)and 3103 (Trip 2)

Perform this test for External Trip Function 1 onlyif Address 3001 = On, an input is programmed forEvent 4526, and Address 3003 is not 0.00seconds .

Perform this test for External Trip Function 2 only ifAddress 3101 = On, an input is programmed forEvent 4546, and Address 3103 is not 0.00seconds .

Connect the 7UT51 as shown in Figure 27. Turn Onthe timer now.

External Trip Function 1

2. Program Discrete Input 1 for Event 4526>External trip 1 act.HI . The event can be setfor act.LO if desired.

3. Program Trip Relay 1 for Event 4537 Externaltrip 1: General TRIP .

4. Program Trip Relay 2 for Event 4536 Externaltrip 1: General fault detect .

5. Set Address 3002 either much greater than, ormuch less than, Address 3003. The reason forthis step is trip delay times may be measured inthis test along with the targeted trip dropouttimes. This depends on the timer being used.With the addresses set very differently,measurements of the dropout time should not beconfused with those of the trip time, shouldseveral trials be run.

6. Set the timer to start when the contact of TripRelay 2 opens , and stop when the contact ofTrip Relay 1 opens .

7. Apply (or remove) DC voltage to Input 1 untilTrip Relay 1 operates.

8. Reset the timer if necessary, disregarding anyreading.

9. Remove (or apply) the DC from Input 1.


11. Set Address 3002 for the original setting.

12. Reset targets.

External Trip Function 2

Follow steps 1-11 for External Trip Function 1,except use:Event 4546 >External trip 2 act.HI in Step 1.

Event 4557 External trip 2: General TRIP inStep 2.

Event 4556 External Trip 2: General Fault Detectin Step 3.

Address 3102 in steps 4 and 10.

Expected Results

The value from the timer in step 9 is the direct,tested value for Address 3003 or Address 3103.The tested value should be within the larger of +/-3% or +/- 13 ms of Address 3003 or Address 3103.

Operations of the contacts and targets should beconsistent with test 23.

Reset 7UT51 for Desired Settings

Program Trip Relay 1 and 2, Signal Relays 1, 2, and3, LEDs 2, 3, and 4, and Discrete Input 1 for thedesired settings. Reset any other addresseschanged during testing to the original settings.

Test 26. Verification of Other Discrete InputFunctions

If any of the discrete input events 0003 though 0393,excluding Event 0356, is being used, the functionshould be verified at this time. Apply (or remove)DC voltage to the input(s) and observe the results.

The other discrete input functions of interest havebeen, or will be, checked elsewhere in theprocedure.

7UT51 v3

62 PRCM-1108A-0199

Time Overcurrent Backup Protection50/51 and 50HS

Overcurrent protection is existent and operationalwhen settings other than Disabled and Off areselected for Addresses 7821 and 2101, respectively.

Notes about Testing Overcurrent Protection

The overcurrent backup protection consists of twoelements: 50/51 and 50HS. The 50/51 element canbe either a 50 or a 51. Both 50 and 50HS can haveno intentional delay, a definite time trip delay, or aninfinite delay (trip defeated). The 51 can havevarious inverse time characteristics with selectabletime dials, or an infinite delay.

Both 50/51 and 50HS measure the currents in eachphase of the winding or object. Both elements willrespond quickest to the highest phase current;therefore, the elements can be tested with single-phase current injection.

The characteristic (either 50 or 51) of 50/51 isselected in Address 2111. The pickup current andtime delay for each characteristic are selected withdifferent addresses. While the pickup and delaysettings for the inactive characteristic appear inWINDIGSI, they should be ignored. Only thesettings for the active characteristic are used by the7UT51. For example, if 51 is selected, pickup andtime delay settings for 50 to appear. These settingsshould be ignored.

The setting for Address 7821 determines thewinding or object that 50/51 and 50HS monitor.

Note: The addresses associated with the pickupcurrents of 50/51 and 50HS are multiples ofthe rated current of the winding or monitoredobject: INsecWx or IObjsec.

Without setting modifications, 87 operations arelikely to occur during testing of 50/51 and 50HS,unless the overcurrent elements are protecting avirtual object. Operations of a 49 element couldoccur as well. To prevent unwanted operations of87 or 49, change addresses 1601, 2401 (49-1) and2501 (49-2) to Off while testing the overcurrentelements. Reset the addresses to the originalsettings after the testing is complete.

Test 27. Pickup and Dropout of 50/51:Address 2112 or 2114

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’

Test Equipment7UT51 Relay

I1

SignalContact 1

W1

W2

W3(7UT513only)

Connect toone phaseof windingassociatedwith50/51/50HS

ContactMonitor

(optional)

7B1

8B1


Connect the current source to one phase of thewinding being monitored by 50/51, as indicated inFigure 28.

The LEDs and contacts may not be programmed tooperate for only the pickup of 50/51. This is true forthe default programming. There are severalprogramming options to obtain indication of just thepickup of 50/51. To minimize reprogramming, therecommendation is to set one LED for Event 2422nm only (nm is needed to test dropout), and test byvisual indication of the LED. The procedure iswritten for this recommendation. If contact operationis desired, a signal contact can be programmed forEvent 2422. A trip contact can be programmed forEvent 2411, but 50/51 must have a lower pickupcurrent than 50HS.

1. Program LED 4 for only Event nm 2422 BU50/51 –Phase O/C fault det .

2. Slowly increase the current from 0 A until LED 4lights. Record the pickup current.

3. Slowly reduce the current until the LED 4 lightextinguishes. Record the current at dropout.Also note LCD indications. Turn Off the current.

4. Re-program LED 4 for the desired setting.

7UT51 v3

PRCM-1108A-0199 63

Expected Results:


The pickup current at LED 4 illumination should bewithin +/- 10% of:

[Address 2112] X [INsecWx or IObjsec] if Address2111 is Definite Time[Address 2114] X [INsecWx or IObjsec] if Address2111 is an inverse option.

The dropout current when LED 4 turns off should begreater than or equal to 93% of the tested pickupcurrent.


For the default settings and recommended change,only LED 4 should light if 51 is being tested. TheLCD should show Back Gen. Flt when 51 drops out.Depending on the time delay for 50, LEDs andcontacts programmed for 50 tripping may transitionduring the test. If a trip occurs, the second line ofthe LCD should indicate BU Gen.Trip .

Test 28. Time Delay of 51 Tripping:Address 2115

If Address 2111 is Definite Time , skip this test.

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)

TimerSTOP

START I1 ON



Connect the current source to one phase of thewinding being monitored by 51, as shown inFigure 29.

1. Program Trip Relay 1 to include Event 2451 BUOvercurrent+G/F : General Trip . (The defaultsettings include this).

2. Set the test current magnitude to provide a solidpickup of 51, based on the results from Test 27.A current greater than or equal to twice thepickup current is highly recommended. (Thecurrent must be greater than 110% of the pickupcurrent.) Be careful to set the current so thatonly 51 trips. If 50HS will operate, the pickupcurrent (Address 2103) can temporarily be sethigher, or the 50HS time delay (Address 2104)can be temporarily set to +* (infinite).

Note : Always be careful not to exceed the currentrating of the 7UT51.

3. Set the timer to start on the application ofcurrent, and stop on the closure of the contact ofTrip Relay 1.


5. Record 51 trip time, LEDs and LCD.

6. Turn Off current, reset LEDs and LCD, but keepthe connections and test-set settings for tests 30and 31.

Expected Results:

Tripping Time

Use the equation below, making the appropriatesubstitutions based on Address 2111, to calculatethe expected trip time. The tested time of 51 shouldbe within +/- 7% of the calculated value.

51 Trip Time (seconds) = {(A/B) + C} X Address 2115

where:

B = [ M y – 1]M = test current in multiples of 51 pickup= test current 51 pickup

51 Pickup = [Address 2114]x[I NsecWx or IObjsec ]

7UT51 v3

64 PRCM-1108A-0199

Address2111

Y A C

ModeratelyInverse

0.02 0.054196 0.09328

VeryInverse

2.0 19.138 0.48258

ExtremelyInverse

2.0 28.2785 0.12173


For the default settings, LEDs 1 and 4 should lightwhen 51 trips. Depending on the time dial settingand applied current, the time delay before a 51 tripmay be noticeable. All trip contacts and contactsassociated with Signal Relays 1 and 3 should togglewhen 51 trips. When the current is Off , the LCDshould read Back Gen. Flt and BU Gen.Trip .

Test 29. Time Delay of 50 Tripping:Address 2113

If Address 2111 is Definite Time , perform this test.Otherwise, go to the next test.

If Address 2113 = 0.00 seconds , this test can beskipped unless Address 2121 = 51 Inverse w/oDelay . In this case, perform the test because theresults are needed for Test 30.

Two options for testing Address 2113 are presented.With two exceptions, Option 1 is recommendedbecause more accurate results are produced.Option 1 does require a standalone timer that isstarted on a contact closure, and stopped on aclosure of a second contact. If Address 2113 = 0.00seconds , Option 2 must be performed. If Address2113 = +* (infinite) seconds , Option 2 should bedone.

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1

TripContact 1

W1

W2

W3(7UT513only)

5A1

5A2 STOP

START

TimerOption 1

Timer

Option 2STOP

START I 1 ON

Connection

Option 2

Connect to onephase of windingAssociated with

50/51/50HS

TripContact 2

5B2

5B1

Figure 30: Test 29 Connections Diagram

Connect the 7UT51 as shown in Figure 30, withcurrent injected into one phase of the winding beingmonitored by the overcurrent protection.

Option 1 :

1. Program Trip Relay 1 for 2411 Back-UpO/C+G/F: General fault detected .

2. Program Trip Relay 2 for 2451 BUOvercurrent+G/F : General Trip . (The defaultsetting is sufficient.)

3. Set the current source magnitude for a valuethat will provide a solid pickup of 50, based onthe results from Test 27. Twice the pickup of 50is a good value for the test current.

Note: Be certain not to pick up 50HS. Temporarilyincrease the pickup of 50HS (Address 2103),if necessary.



6. Record the value from the timer. This is thetested value for Address 2113. If Address 2113is infinite (+*), the timer should not stop.

7. Turn Off the current, reset the LEDs and LCD,but keep the connections and testset settings fortests 30 and 31.

7UT51 v3

PRCM-1108A-0199 65

Option 2 :

1. Program Trip Relay 1 to include 2451 BUOvercurrent+G/F : General Trip . (The defaultsetting includes this signal.)

2. Set the current source magnitude for a valuethat will provide a solid pickup of 50, based onthe results from Test 27. Twice the pickup of 50is a good value for the test current.

Note: Be certain not to pickup 50HS. Temporarilyincrease the pickup of 50HS (Address 2103),if necessary.


4. If Address 2113 is infinite (+*), continue toStep 5. Otherwise, skip to step 8.


6. Verify the timer does not stop, and no othercontacts or LEDs programmed for the tripping of50 to operate. (Action from the pickup of 50 isproper.)

7. Turn Off the current, and reset the LEDs andLCD if applicable. End of test.



10. Record the pickup time of 50 plus the outputcontact.

11. Repeat steps 9 and 10 two or more times, toobtain a pickup timespread for 50 and contact.

12. If Address 2113 = 0.00 seconds is the desiredsetting, end of test. Reset the LEDs and LCD,but keep the connections and test-set settingsfor Test 30. Otherwise, continue.



15. Turn the current Off , reset the LEDs and LCD,but keep the connections and testset settings fortests 30 and 31.

Expected Results:

Option 1:

The value read from the timer is the direct, testedvalue for Address 2113. The value should be withinthe larger of +/- 3% or +/- 13 ms of Address 2113.

For the default settings, LEDs 1 and 4 should lightwhen 50 trips. Depending on Address 2113, the

time lag between application of current and 50tripping can be noticeable. All trip contacts andcontacts associated with signal relays 1 and 3should toggle when 50 trips. When the current isOff , the LCD should show Back Gen. Flt and BUGen.Trip .

Option 2:

If only Address 2113 = 0.00 seconds is tested, theresults indicate the inherent operating time of 50.Expect times in the range of [30 to 40] ms at 2 timespickup.

The pickup times from Step 11 (2113 = 0.00seconds ) must be subtracted from the pickup timeof Step 14 (2113 = Desired Setting ) to obtain thetested values for Address 2113. The accuracy ofAddress 2113, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms. The pickuptimespread of 50 (without delay) plus contact mustbe considered.

The pickup timespread of 50 plus contact can adderrors and uncertainty to the results. If the user isnot satisfied with the tested value for Address 2113,the Network Disturbances option in the WinDIGSIsoftware can be useful.

Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor Event 2422 coming, BU 50/51 – Phase O/C faultdet ., from Event 2442 coming BU 50/51 –Overcurrent timer expired , to obtain the delaycaused by Address 2113.

For the default settings, LEDs 1 and 4 should lightwhen 50 trips. Depending on Address 2113, thetime lag between application of current and 50tripping can be noticeable. All trip contacts andcontacts associated with signal relays 1 and 3should toggle when 50 trips. When the current isOff , the LCD should read Back Gen. Flt and BUGen.Trip .

Test 30. Manual Close Controlling 50/51Tripping Delay: Address 2121

Perform this test only if Address 2121 = 51 Inversew/o Delay .

7UT51 v3

66 PRCM-1108A-0199

1. Energize (or de-energize if appropriate) thediscrete input to cause the coming of Event0356 > Manual close command.

Address 2111 Set for 51

2. Repeat Test 28.3. Record the trip time of 51.

4. If the timer does not turn Off the current uponsensing contact closure, switch the state of thediscrete input to cause the going of Event 0356.Note the response of the 7UT51. End the test.If the timer turns Off the current, continue.

5. Remove the timer sensing.

6. Apply the current to Cause 51 tripping.

7. Switch the state of the discrete input to causethe going of Event 0356.

8. Note the response of the 7UT51. End the test.

Note: Address 2111 = Definite Time, Option 1Performed in Test 29.

9. Repeat Test 29, Option 1, but do not turn Offcurrent at the end.


11. With the current still applied, toggle the discreteinput associated with Event 0356.

12. Note the response by the 7UT51. End the test.

Note: Address 2111 = Definite Time, Option 2Performed in Test 29.

13. Repeat Test 29, Option 2, but only with Address2113 = Desired Setting .

14. Record the trip time of 50.

15. If the timer does not turn Off the current uponsensing contact closure, switch the state of thediscrete input to cause the going of Event 0356.Note the response of the 7UT51. End the test.If the timer turns Off the current, continue.


17. Apply the current to Cause 50 tripping.


19. Note the response of the 7UT51. End of test.

Expected Results :

Both 51 and 50 should trip without any delay, otherthan the inherent delay, when Event 0356 is active

and current exceeds the pickup of the element.Once tripped, 51 and 50 should reset only after thecurrent decreases below the element dropout level.A change in state of the discrete input causing Event0356 should not drop out 51 or 50 if current abovethe element pickup is present. This tripping andresetting action should be true even if 50/51 timedelay is infinite.

The inherent delay of 51 is about 35 ms at 2 timespickup.

For Option 1, the timer may read from 0 ms to about3 ms because of the difference in operating times ofthe trip contacts, and the accuracy of the timer.

For Option 2, the state of the discrete input shouldnot effect 50 tripping times when Address 2113 =0.00 seconds .

LED, LCD, and contact operations should be thesame as in tests 28 or 29, provided the delay of 51or 50 tripping is not infinite seconds.

Test 31. Status Control of 50/51:Discrete Inputs Or Address 2101

If the operational status of 50/51 is controlled by adiscrete input(s), tests 28 or 29 can be repeated withthe input in the opposite state, to verify the control isfunctioning. Also, if multiple sets of protectionsettings are used, and Address 2101 is Off or BlockTripping in any of these sets,tests 28 or 29 can berepeated with these settings to verify properoperation of 50/51.

If 50 is operational but Test 29 was not performed,use Test 29 to check Address 2101 settings of Offor Block Tripping . If 50 is controlled by an input,perform Test 29 twice – once with the controlapplied, and once without the control.

Expected Results :

Address 2101 = Off and an input causing thecoming of Event 2303 >Block back-up O/C timeprotection should have similar effects. Eithershould effectively render 50/51 non-existent. Notargets or contacts programmed for any 50/51events should operate. If 50/51 is first tripped, andthen Event 2303 is activated, the event should haveno effect. The 7UT51 should remain tripped with allLEDs and contacts reflecting 50/51 tripping. If theevent is first activated, then current is applied to the7UT51, the 7UT51 should respond as if 50/51 were

7UT51 v3

PRCM-1108A-0199 67

non-existent. If the event is then de-activated(going) while current is still present, 50/51 should tripand provide LEDs and outputs in the normal fashion.

Address 2101 = Block Tripping and an input causingthe coming of Event 2304 >Block trip signal ofbackup O/C , applied before a 50/51 trip, shouldhave similar effects. Either should prevent tripcontacts from operating for all 50/51 events exceptEvent 2411, described below. The events belowshould be free to operate signal relays or LEDs.

Event 2411 Backup O/C+G/F: General faultdetected

Event 2412 BU O/C : Fault detection PhA (ifcurrent in phase A exceeds p.u.)

Event 2413 BU O/C : Fault detection PhB (ifcurrent in phase B exceeds p.u.)

Event 2414 BU O/C : Fault detection PhC (ifcurrent in phase C exceeds p.u.)

Event 2422 BU 50/51: Phase O/C fault det .

Event 2442 BU 50/51: Overcurrent timer expired(with or without time delay)

Event 2451 BU Overcurrent+G/F: General Trip

For the default LCD settings, Back Gen. Flt shouldbe shown when 50/51 operates with Address 2101 =Block Tripping or Event 2304 active .If 50/51 is first tripped, and then Event 2304 isactivated, contacts and LEDs in the 7UT51 shouldnot change. The 7UT51 should remain in a tripstate. Event 2304 should be essentially ignored. Ifa trip contact programmed for Event 2442 or 2451 isblocked because of Event 2304, and then the inputis changed to cause the going of Event 2304 whilecurrent above the pickup value of 50/51 is stillapplied, the trip contact should remain blocked.

Event 2307 >Block 50/51 Stage of Backup O/Cshould prevent 50/51 from timing-out, and hencetripping, but should not inhibit 50/51 from picking up.This means trip contacts should be blocked for all50/51 events except Event 2411. LEDs and signalrelays programmed for events 2442 and 2451should be blocked. LEDs and signal relaysprogrammed for events 2411-2414, and 2422,should be free to operate. For the default LCDsettings, Back Gen. Flt should appear when 50/51is picked up while Event 2307 is active. The actionof Event 2307 should occur even if Address 2113 =0.00 seconds .

If 50/51 is first tripped, and then Event 2307 isactivated, no change should occur. The 7UT51should remain in a trip state with contacts andtargets reflecting the 50/51 trip. Event 2307 shouldbe essentially ignored. If Event 2307 is preventingthe timeout of 50/51, and then the event isdeactivated, 50/51 should trip. Trip contacts, signalcontacts, and LEDs programmed for Event 2442,2451, or a general trip of the 7UT51 should operate.The LCD (default settings) should show Back Gen.Flt and BU Gen.Trip .

Undo Settings Changes

Settings changes made in Test 28 or 29 should beundone at this point. Pay particular attention to thetrip contacts.

Test 32. Trip Dropout after Reset of 50/51:Address 2118

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)

TimerSTOP

START I1 OFF

Connect to onephase ofwindingassociated with50/51/50HS



1. Program Trip Relay 1 for Event 2451 BUOvercurrent+G/F : General trip . (The defaultsetting is sufficient.)


3. Set the timer to start when the current is turnedOff , and stopped when the contact transitionsfrom closed to open.

7UT51 v3

68 PRCM-1108A-0199

4. Set the current source for a magnitude that willprovide a trip of 50/51. The value used in tests28 or 29 is good. Be sure to trip only 50/51.Set the pickup of 50HS (Address 2103) higher, ifnecessary.

5. Apply the current until 50/51 trips.


7. Record the trip dropout value given by the timer.

8. If the desired setting of Address 2118 = 0.00seconds , go to Step 12. Otherwise, go to thenext step.

9. Repeat steps 5-7 two or more times todetermine a timespread for the dropout time of50/51 plus contact.




13. Program Trip Relay 1 for the original setting.

Expected Results:

With Address 2118 = 0.00 seconds , the dropouttime of 50 or 51, plus the contact, should be 50 ms+/- 13 ms , with a current of twice the pickup valuedropping suddenly to 0 A after 50/51 trips.

The dropout times from Step 9 (2118 = 0.00seconds ) must be subtracted from the dropout timeof Step 11 (2118 = desired setting ) to obtain thetested value for Address 2118. The accuracy ofAddress 2118, including the timer accuracy, is thelarger of +/- 3% or +/- 10 ms . The dropouttimespread of 50/51 (without delay) plus contactmust be considered. The spread is typically widerwhen the pickup of 50/51 is less than 0.5 amp .

Contact and target operations should be the sameas in tests 28 or 29.

Notes about Testing 50HS

Depending on the application, a high current may berequired to pickup 50HS.

Note: Do not exceed the current limitations of the7UT51, given at the beginning of thisdocument.

If the 50HS pickup current is less than 20 amps (4amps for a 7UT51 rated for 1 amp ), a precise

pickup level is determined in Test 33. If the 50HSpickup current is greater than 20 amps (4 amps ),the test for a precise pickup is foregone. A testcurrent of 1.2 X 50HS pickup is used for verificationof a modified 50HS pickup, in tests 34 and 35.

If 50/51 has a lower pickup current than 50HS, thenthe 50/51 pickup must be raised well above the50HS pickup for Test 34 (timing test of 50HS). Thissetting change simplifies the other 50HS tests aswell. Therefore, at this point, raise the 50/51 pickupwell above the 50HS pickup. A 50/51 pickup above20 amps should be selected.

Test 33. Pickup and Dropout of 50HS:Address 2103

This test is only to be done if 50HS pickup is 20amps or less (4 amps or less if the 7UT51 is ratedfor 1 amp).

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’

Test Equipment7UT51 Relay

I1

SignalContact 1

W1

W2

W3(7UT513only)


ContactMonitor

(optional)

7B1

8B1


Connect the current source to one phase of thewinding being monitored by 50HS, as shown inFigure 32.

Pickup of 50HS can be determined by monitoringany LED or contact programmed for Event 2451(LED 4, Signal Relay 3 contact, and any trip contactwith the default settings) if the 50HS pickup is lessthan the 50/51 pickup, and the time delay of 50HStripping (Address 2104) is accommodated. For thegeneral procedure given below, LED 4 isprogrammed to operate only for Event 2421 nm (nmis needed to test dropout). Pickup determination isby visual indication of LED 4. If desired, a signalrelay can be programmed for Event 2421 also.

1. Program LED 4 for only Event nm 2421 BU50HS -Phase highset OC fault det.

7UT51 v3

PRCM-1108A-0199 69

2. Slowly raise the current until LED 4 lights.Record the pickup current.

3. Slowly reduce the current until the LED 4 lightextinguishes. Record the current at dropout.Also note LCD indications. Turn Off the current.

4. Reprogram LED 4 for the desired setting.

Expected Results :


The pickup current at LED 4 illumination should bewithin +/- 5% of:[Address 2103] X [INsecWx or IObjsec]

The dropout current when LED 4 turns off should begreater than or equal to 93% of the tested pickupcurrent.


For the default settings and recommended change,only LED 4 should light if 50HS does not trip, andthe LCD should show Back Gen. Flt when 50HSdrops out. If 50HS trips, LEDs 1 and 4 should light,contacts of Signal Relays 1 and 3 should toggle, alltrip contacts should operate, and the second line ofthe LCD should indicate BU Gen.Trip .

Test 34. Time Delay of 50HS Tripping:Address 2104

If Address 2104 = 0.00 seconds , skip to Test 37unless Address 2121 = 50HS IOC w/o Delay,Address 2101 = Off or Block Tripping in any settinggroup, or discrete inputs control the operationalstatus of 50HS. Otherwise, perform this test, andcontinue to the next one.

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1

Trip Contact 1

W1

W2

W3 (7UT513 only)

5A15A2 STOP

START

Timer Option 1

Timer

Option 2STOP

START I1 ON

ConnectionOption 2

Connect to onephase of windingAssociated with50/51/50HS

Trip Contact 2

5B2

5B1


This test requires 50HS to be solidly picked up for atime greater than Address 2104. To simplify theprocedure and alleviate concerns about thermaldamage to the 7UT51, a setting change of Address2103 (50HS pickup) may be required.Two options for testing Address 2104 are presented.With two exceptions, Option 1 is recommendedbecause more accurate results are produced.Option 1 does require a stand-alone timer that isstarted on a contact closure, and stopped on aclosure of a second contact. If Address 2104 = 0.00seconds , Option 2 must be performed. If Address2104 = +* (infinite) seconds , Option 2 should bedone.

Connect the 7UT51 as shown in Figure 33, withcurrent injected into one phase of the winding beingmonitored by 50HS.

Option 1 :

1. The pickup of 50HS = Address 2103 X[INsecWx or IObjsec] . If the pickup is greaterthan 16.5 amps , change Address 2103 so thatthe 50HS picks up at 16.5 amps or less.

2. Program Trip Relay 1 for 2411 BackupO/C+G/F: General fault detected .

3. Program Trip Relay 2 for 2451 BUOvercurrent+G/F : General Trip . (The defaultsetting is sufficient.)

4. Set the current source magnitude for 20 amps(4 amps for a 7UT51 with a 1 amp rating).

Note: Be sure 50/51 pickup is greater than 20 amps.


7UT51 v3

70 PRCM-1108A-0199


7. Record the value from the timer. This is thetested value for Address 2104. If Address 2104is infinite (+*) seconds, the timer should notstop.

8. Turn Off the current, reset the LEDs and LCD.

9. Program Trip Relays 1 and 2 for the original,intended settings.

Option 2 :

1. The pickup of 50HS = Address 2103 X[INsecWx or IObjsec] . If the pickup is greaterthan 16.5 amps, change Address 2103 so thatthe 50HS picks up at 16.5 amps or less.

2. Program Trip Relay 1 to include 2451 BUOvercurrent+G/F : General Trip . (The defaultsetting includes this signal.)

3. Set the current source magnitude for 20 amps(4 amps for a 7UT51 rated for 1 amp ).

Note: Be sure 50/51 pickup is greater than 20 amps.




7. Verify the timer does not stop, and no othercontacts or LEDs programmed for the tripping of50HS operate. (Action from the pickup of 50HSis proper.)

8. Turn Off the current and reset the LEDs andLCD if applicable. Keep the connections, test-set settings, and 7UT51 settings if Test 35 is tobe done. Otherwise, program Trip Relay 1 forthe intended settings. End of test.



11. Record the pickup time of 50HS plus the outputcontact.

12. Repeat steps 10 and 11 two or more times, toobtain a pickup timespread for 50HS andcontact.

13. If Address 2104 = 0.00 seconds is the desiredsetting, end of test. Turn Off the current andreset the LEDs and LCD. Keep the connections,test-set settings, and 7UT51 settings for Test 35.Otherwise, continue.



16. Turn the current Off and reset the LEDs andLCD. Keep the connections, test-set settings,and 7UT51 settings if Test 35 is to be done.Otherwise, program Trip Relay 1 for theintended settings.

Expected Results:

Option 1:


For the default settings, LEDs 1 and 4 should lightwhen 50HS trips. Depending on Address 2104, thetime lag between application of current and 50HStripping can be noticeable. All trip contacts andcontacts associated with Signal Relays 1 and 3should toggle when 50HS trips. When the current isOff , the LCD should read Back Gen. Flt and BUGen.Trip .

Option 2 :

With Address 2104 = 0.00 seconds , the resultsindicate the inherent operating time of 50HS.Expect times in the range of [30 to 40] ms at 1.2times pickup.

The pickup times from Step 12 (2104 = 0.00seconds ) must be subtracted from the pickup timeof Step 15 (2104 = desired setting ) to obtain thetested value for Address 2104. The accuracy ofAddress 2104, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms. The pickuptimespread of 50HS (without delay) plus contactmust be considered.

The pickup timespread of 50HS plus contact canadd errors and uncertainty to the results. If the useris not satisfied with the tested value for Address2104, the Network Disturbances option in theWINDIGSI software can be useful.

Obtain dialog with the 7UT51. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor Event 2421 coming, BU 50HS –Phase highsetOC fault det. , from Event 2441 coming BU 50HS –Highset O/C time expired , to obtain the delayassociated with Address 2104.

7UT51 v3

PRCM-1108A-0199 71

For the default settings, LEDs 1 and 4 should lightwhen 50HS trips. Depending on Address 2104, thetime lag between application of current and 50HStripping can be noticeable. All trip contacts andcontacts associated with Signal Relays 1 and 3should toggle when 50HS trips. When the current isOff , the LCD should show Back Gen. Flt and BUGen.Trip .

Test 35. Manual Close Controlling50HS Tripping Delay: Address 2121

Perform this test only if Address 2121 = 50 HS IOCw/o Delay .

1. Energize (or de-energize if appropriate) thediscrete input to cause the coming of Event0356 >Manual close command.

Option 1 Performed in Test 34:

2. Repeat Test 34, Option 1, but do not turn Offcurrent at the end.


4. With the current still applied, toggle the discreteinput associated with Event 0356.

5. Note the response by the 7UT51. End of test.

Option 2 Performed in Test 34:

6. Repeat Test 34, Option 2, but only with Address2104 = desired setting .

7. Record the trip time of 50HS.

8. If the timer does not turn Off the current uponsensing contact closure, switch the state of thediscrete input to cause the going of Event 0356.Note the response of the 7UT51. End of test. Ifthe timer turns off the current, continue.


10. Apply the current to cause 50HS tripping.


12. Note the response of the 7UT51. End of test.

Expected Results:

When Event 0356 is active and current exceeds thepickup of 50HS, the element should trip withoutdelay, other than inherent delay. Once tripped,50HS should reset only after the current decreasesbelow the element dropout level. A change in stateof the discrete input causing Event 0356 should not

drop out 50HS if current above the element pickup ispresent. This tripping and resetting action should betrue even if 50HS time delay is infinite seconds.

The inherent delay of 50HS is about 35 ms at 1.2times pickup.

For Option 1, the timer may read from 0 ms to about3 ms because of the difference in operating times ofthe trip contacts, and the accuracy of the timer.

For Option 2, the state of the discrete input shouldnot effect 50HS tripping times when Address 2113 =0.00 seconds .

LED, LCD, and contact operations should be thesame as in Test 34, unless the tripping delay of50HS is infinite seconds.

Test 36. Status Control of 50HS:Discrete Inputs or Address 2101

If the operational status of 50HS is controlled by adiscrete input(s), test 34 can be repeated with theinput in the opposite state, to verify the control isfunctioning. Also, if multiple sets of protectionsettings are used, and Address 2101 is Off or BlockTripping in any of these sets, Test 34 can berepeated with these settings to verify properoperation of 50HS.

Expected Results:

Address 2101 = Off and an input causing thecoming of Event 2303 >Block Backup O/C TimeProtection should have similar effects. Eithershould effectively render 50HS nonexistent. Notargets or contacts programmed for any 50HS eventshould operate. If 50HS is first tripped, and thenEvent 2303 is activated, the event should have noeffect. The 7UT51 should remain tripped with allLEDs and contacts reflecting 50HS tripping. If theevent is first activated, then current is applied to the7UT51, the 7UT51 should respond as if 50HS isnonexistent. If the event is then deactivated (going)while current is still present, 50HS should trip andprovide LEDs and outputs in the normal fashion.

Address 2101 = Block Tripping and an inputcausing the coming of Event 2304 >Block TripSignal Of Backup O/C , applied before a 50HS trip,should have similar effects. Either should preventtrip contacts from operating for all 50HS eventsexcept Event 2411, described below. The events

7UT51 v3

72 PRCM-1108A-0199

below should be free to operate signal relays orLEDs.

Event 2411 Back-up O/C+G/F: General faultdetected

Event 2421 BU 50HS –Phase highset OC fault det.

Event 2441 BU 50HS –Highset O/C time expired(with or without time delay)

Event 2451 BU Overcurrent+G/F : General Trip

Note: Events 2412, 2413, 2414, 2422, and 2442pertain to 50/51 only.

For the default LCD settings, Back Gen. Flt shouldbe shown when 50HS operates with Address 2101 =Block Tripping or Event 2304 active.

If 50HS is first tripped, and then Event 2304 isactivated, contacts and targets in the 7UT51 shouldnot change. The 7UT51 should remain in a tripstate. Event 2304 should be essentially ignored. Ifa trip contact programmed for Event 2441, 2442, or2451 is blocked because of Event 2304, and thenthe input is changed to cause the going of Event2304 while current above the pickup value of 50HSis still applied, the trip contact should remainblocked.

Event 2306 >Block 50HS stage of backup O/Cshould prevent 50HS from timing-out, thereforetripping, but should not inhibit 50HS from picking up.The 50HS tripping should be prevented even ifAddress 2104 = 0.00 seconds . This means thatevents 2441 and 2451 should be blocked fromoperating trip relays, signal relays, and LEDs.Events 2411 and 2421 should still be free to occur,and they should be capable of operating trip relays(2411), signal relays, and LEDs. For the defaultLCD settings, Back Gen. Flt should appear when50HS is picked up while Event 2306 is active.

If 50HS is first tripped, and then Event 2306 isactivated, no change should occur. The 7UT51should remain in the trip state with contacts andLEDs reflecting the 50HS trip. Event 2306 shouldbe essentially ignored. If Event 2306 is preventingthe timeout of 50HS, and then the event isdeactivated, 50HS should trip. Trip relays, signalrelays, and LEDs programmed for events 2441,2451, or a general trip of the 7UT51 should operate.The LCD (default settings) should show Back Gen.Flt and BU Gen.Trip .

Note: Program Trip Relays 1 and 2 for the original,intended settings

Test 37. Trip Dropout after Reset of 50HS:Address 2118

Address 2118 applies to both 50/51 and 50HS. Test32 is done with 50/51 tripping. This test applies for50HS tripping.

IC

IB

IA

Ic

Ib

Ia

Ic’

Ib’

Ia’


I1Trip

Contact 1

W1

W2

W3(7UT513only)

TimerSTOP

START I1 OFF

Connect to onephase ofwindingassociated with50/51/50HS


This test requires 50HS to be solidly picked up. Tosimplify the procedure and alleviate concerns aboutthermal damage to the 7UT51, a setting change ofAddress 2103 (50HS pickup) may be required.


1. The pickup of 50HS = Address 2103 X[INsecWx or IObjsec] . If the pickup is greaterthan 16.5 amps, change Address 2103 so thatthe pickup is 16.5 amps or less.

2. Be sure Trip Relay 1 includes Event 2451 BUOvercurrent+G/F : General Trip . (The defaultsetting includes this).


4. Set the timer to start when the current is turnedOff , and stop when the contact transitions fromclosed to open.

5. Set the current source for 20 amps (4 amps fora 7UT51 rated for 1 amp).

Note: Be sure 50/51 pickup is greater than 20amps .

6. Apply the current until 50HS trips.


7UT51 v3

PRCM-1108A-0199 73



10. Repeat steps 6-8 two or more times todetermine a timespread for the dropout time of50HS plus contact.



16. Set Address 2103 for the original, desiredsetting.

17. Program the Trip Relays for the original, desiredsettings.

Expected Results:

With Address 2118 = 0.00 seconds , the dropouttime of 50HS, plus the contact, should be 50 ms +/-13 ms, with a current of [1.2 X pickup value]dropping suddenly to 0 A after 50HS trips.

The dropout times from step 10 (2118 = 0.00seconds ) must be subtracted from the dropout timeof step 12 (2118 = desired setting ) to obtain thetested value for Address 2118. The accuracy ofAddress 2118, including the timer accuracy, is thelarger of +/- 3% or +/- 10 ms . The dropouttimespread of 50HS (without delay) plus contactmust be considered.

For the default settings, LEDs 1 and 4 should lightwhen 50HS trips. All trip contacts and contactsassociated with signal relays 1 and 3 should togglewhen 50HS trips. The contacts should remaintripped until the dropout timer expires. When 50HSdrops out, the LCD should display Back Gen. Fltand BU Gen.Trip .

Note: Set all Settings Pertaining to 50/51 to theDesired Values

Tank Leakage Protection

The tests for tank leakage protection (64T) applyonly to a 7UT513 fitted with the 64T option.

The protection is existent and operational whensettings other than Nonexistent and Off areselected for Addresses 7827 and 2701, respectively.

Notes about Testing Tank Leakage Protection

To make 64T existent, one of two settings areselected for Address 7827. There are importantdifferences between the two settings.

Address 7827 = Sensitive CT B• Load current to test 64T in terminals [1D1-1D2].

Terminal 1D1 has polarity.

• Pickup current for 64T is given in Address 2704.The unit is milliamps.

Address 7827 = Insensitive CT A• Load current to test 64T in terminals [2D1-2D2].

Terminal 2D1 has polarity.

• Pickup current for 64T is given in Address 2703.The setting is a multiple of the rated current ofthe 7UT513: 5 amps or 1 amp.

Test 38. Pickup and Dropout of Tank LeakageProtection: Address 2703 or 2704, andAddress 2709

Address 7827= SensitiveCTB, connectI1 to INb

Address 7827= InsensitiveCTA, connectI1 to INa

IC

IB

IA

Ic

Ib

Ia


I1ContactMonitor

TripContact 1

W1

W2

I1

1D1

1D2

2D1

2D2

INb

INa

W3 notshown

or


Connect the 7UT513 as shown in Figure 35, usingthe proper connections according to Address 7827.

A trip contact is monitored in the steps below while64T pickup and dropout are tested. Monitoring a tripcontact is recommended because 64T is thenverified from input to important outputs. The timedelay of 64T tripping – Address 2725 – must beaccommodated as the current is ramped up to testpickup. Likewise, the dropout delay – Address 2727– must be considered as the current is decreased tocheck dropout. If either of these delays isexcessive, the test can be easily adapted. Pickupand dropout of 64T can be tested with visualinspection of an LED programmed for Event nm5916 Transformer tank prot.: Pickup . Addresses2725 and 2727 would not effect the LED. The LEDwould have to be reprogrammed to the originalsetting after the test was completed.

7UT51 v3

74 PRCM-1108A-0199

1. Program Trip Relay 1 to include Event 5921Transformer tank prot.: General TRIP . (Thedefault setting is sufficient.)

2. Slowly increase the current from 0 A until thecontact of Trip Relay 1 closes. Record thepickup current at contact closure. Record othercontact and LED operations.

3. Slowly reduce the current until the contact dropsout. Record the current at dropout. Recordchanges of contacts, LEDs, and the LCD.

4. Turn Off the current. Reset the LEDs and LCD.

Expected Results :


The pickup current at contact closure should bewithin +/- 5% of Address 2704, or [Address 2703 XRated Current of 7UT513].

The dropout current at contact opening should bewithin +/- 5% of [Address 2709 X Tested PickupCurrent].


For the default programming, all trip contacts andthe Signal Relay 9 contact should close, and LEDs 1and 8 should light, when 64T trips. When 64T dropsout, the contacts should reset and the LCD shoulddisplay TankGen FAULT and Tank Gen.TRIP . TheLEDs have memory.

Test 39. Time Delay of Tank LeakageProtection Tripping: Address 2725

If Address 2725 = 0.00 seconds , skip to the nexttest unless Address 2701 = Off or Block Trippingin any setting group, or discrete inputs control theoperational status of 64T. Otherwise, perform thistest.

Two options for testing Address 2725 are presented.With two exceptions, Option 1 is recommendedbecause more accurate results are produced.Option 1 does require a stand-alone timer that isstarted on a contact closure, and stopped on aclosure of a second contact. If Address 2725 = 0.00seconds , Option 2 must be performed. If Address2725 = +* (infinite seconds) , Option 2 should beperformed.

IC

IB

IA

Ic

Ib

Ia


I1Trip Contact 1

W1

W2

W3 not shown

5A1

5A2

STOP

START

Timer Option 1

Timer Option 2

STOP

START I1 ON

Connection

Option 2

Trip Contact 2

INb

INa

1D1

1D2

2D1

2D2

Address 7827 =Sensitive CTB,connect I1 to INb

Address 7827 =Insensitive CTA,connect I1 to INa

I1

or


Connect the 7UT513 according to Address 7827 andthe option selected, as shown in Figure 36.

Option 1:

1. Program Trip Relay 1 to include Event 5921Transformer tank prot.: General Trip . (Thedefault setting is sufficient.)

2. Program Trip Relay 2 for Event 5916Transformer tank prot.: Pickup .

3. Set the timer to start on the closure of the TripRelay 2 contact, and stop on the closure of theTrip Relay 1 contact.

4. Set the current source for a value that willprovide a solid pickup of 64T, based on theresults from Test 38. Current equal to twice thepickup value is good.


6. Record the value from the timer. This is thetested value for Address 2725. If Address 2725is infinite (+*) seconds, the timer should notstop.


8. Maintain the 7UT513 test connections andsettings if Test 40 is to be performed.Otherwise, program Trip Relays 1 and 2 for theoriginal, intended settings.

Option 2:

1. Program Trip Relay 1 to include Event 5921Transformer tank prot.: General Trip . (Thedefault setting includes this signal.)


3. Set the current source for a value that willprovide a solid pickup of 64T, based on the

7UT51 v3

PRCM-1108A-0199 75

results from Test 38. Current equal to twice thepickup value is good.



6. Verify the timer does not stop, and no othercontacts or LEDs programmed for the tripping of64T operate. (Action from the pickup of 64T isproper.)

7. Turn Off the current, and reset the LEDs andLCD, if applicable. Keep the testset connectionsand 7UT513 settings if Test 40 is to be done.End of test.



10. Record the pickup time of 64T plus the outputcontact.

11. Repeat steps 9 and 10 two or more times, toobtain a pickup timespread for 64T plus contact.

12. If Address 2725 = 0.00 seconds is the desiredsetting, end of test. Keep the connections,testset settings, and 7UT513 settings if Test 40is to be done. Otherwise, continue.




16. Keep the connections, test-set settings, and7UT513 settings if Test 40 is to be done.Otherwise, program Trip Relay 1 for the original,intended setting.

Expected Results :

Option 1:


Operations of the contacts, LEDs, and LCD shouldbe consistent with those in test 38, withconsideration given to the programming for TripRelays 1 and 2. Depending on Address 2725, thedelay between the application of current and 64Ttripping may be noticeable.

Option 2:

With Address 2725 = 0.00 seconds , the resultsindicate the inherent tripping time of 64T. Expecttimes in the range of 20 to 30 ms at 2 times pickup.

The pickup times from Step 11 (2725 = 0.00seconds ) must be subtracted from the pickup timeof Step 14 (2725 = desired setting ) to obtain thetested value for Address 2725. The accuracy ofAddress 2725, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms . The pickuptimespread of 64T (without delay) plus contact mustbe considered.

The pickup timespread of 64T plus contact can adderrors and uncertainty to the results. If the user isnot satisfied with the calculated value for Address2725, the Network Disturbances option in theWinDIGSI software can be useful.

Obtain dialog with the 7UT513. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor Event 5916 (64T pickup) from the time for Event5921 (64T General Trip) to get the delay in trippingcaused by Address 2725.

Operations of the contacts, LEDs, and LCD shouldbe consistent with those in Test 38, withconsideration given to the programming for TripRelay 1. Depending on Address 2725, the delaybetween the application of current and 64T trippingmay be noticeable.

Test 40. Status Control of 64T:Discrete Inputs or Address 2701

If the operational status of 64T is controlled by adiscrete input(s), Test 39 can be repeated with theinput in the opposite state, to verify the control isfunctioning. Also, if multiple sets of protectionsettings are used, and Address 2701 = Off or BlockTripping in any of these sets, Test 39 can berepeated with these settings to verify properoperation of 64T.

Expected Results:

Address 2701 = Off and an input causing thecoming of Event 5903 >BLOCK Transformer TankProtection , applied before a 64T trip, should havesimilar effects. Either should effectively make 64Tnonexistent. If 64T is first tripped, and then Event

7UT51 v3

76 PRCM-1108A-0199

5903 is activated, the event should have no effect.The 7UT513 should remain in a tripped state with allcontacts, LEDs, and the LCD reflecting the 64T trip.If (1) the event is first activated, (2) current abovethe pickup of 64T is applied, and then (3) the eventis deactivated with the current still present, 64Tshould trip and provide outputs, LEDs, and an LCDdisplay in the normal fashion.Address 2701 = Block Tripping and an input causingthe coming of Event 5905 >BLOCK transformertank prot trip signal , applied before a 64T trip,should have similar effects. Either should preventEvent 5921 Transformer tank prot.: General TRIPfrom operating trip relays. Events 5916, 5917, and5921 should be uninhibited in operating LEDs andsignal relays. For the default settings, the LCDshould read TankGen FAULT .

If Event 5921 is blocked from operating a trip relaybecause of Event 5905, and then Event 5905 isreleased, Event 5921 should remain blocked.

Applying Event 5905 after 64T has tripped should donothing. The event should be ignored.

Test 41. Trip Dropout after Reset of 64T:Address 2727

IC

IB

IA

Ic

Ib

Ia


I1Trip

Contact 1

W1

W2

I1

1D11D22D12D2

INb

INa

W3 notshown

Address 7827 =Sensitive CTB,connect I1 to INb

Address 7827 =Insensitive CTA,connect I1 to INa

or

STOP

START I1 OFF

Timer

5B15B2


Connect the 7UT51 according to Address 7827, asshown in Figure 37.

1. Program Trip Relay 1 to include Event 5921Transformer tank prot.: General Trip . (Thedefault setting is sufficient.)


3. Set the timer to start when the current is turnedOff , and stop when the Trip Relay 1 contacttransitions from closed to open.

4. Set the current source for a value that willprovide a solid pickup of 64T, based on theresults from Test 38. Current equal to twice thepickup value is good.

5. Apply the current to pickup 64T.




9. Repeat steps 5-7 two or more times todetermine a timespread for the dropout time of64T plus contact.



12. Program Trip Relay 1 and Trip Relay 2 for theoriginal settings.

Expected Results:

With Address 2727 = 0.00 seconds , the dropouttime of 64T plus the contact should be 35 ms +/- 13ms.

The dropout times from Step 9 (2727 = 0.00seconds ) must be subtracted from the dropout timeof Step 11 (2727 = desired setting ) to obtain thetested value for Address 2727. The accuracy ofAddress 2727, including the timer accuracy, is thelarger of +/- 3% or +/- 10 ms. The dropouttimespread of 64T (without delay) plus contact mustbe considered.

Note: Contact, LED, and LCD operations should bethe same as in Test 38.

7UT51 v3

PRCM-1108A-0199 77

Restricted Ground Fault Protection

The tests for restricted ground fault protection (87N)apply only to a 7UT513 fitted with the 87N option.

The protection is existent and operational whensettings other than Nonexistent and Off areselected for Addresses 7819 and 1901, respectively.

Notes about Testing 87N

The ground CT associated with 87N must bedetermined before testing can start. Refer toAddress 7819 to ascertain the winding or objectbeing protected by 87N. Match this address toeither Address 7806 (CT A) or Address 7807 (CT B).The currents in the tests below must be loaded intothe 7UT513 terminals that correspond to theapplicable CT for 87N.

The pickup of 87N is specified as a multiple of therated current of the protected winding or object. Donot use INsecWx and IObjsec for the rated current.Instead, use INRGFWx or IOBJRGF , which apply torestricted ground fault protection only.

INRGFWx =

[87N Phase CT Primary Rating] X I NsecWx

87N Ground CT Primary Rating

87N Phase CT Primary Rating is:• Address 1104 for Winding 1• Address 1124 for Winding 2• Address 1144 for Winding 3

87N Ground CT Primary Rating is:• Address 1107 for Winding 1• Address 1127 for Winding 2• Address 1147 for Winding 3

IOBJRGF = Address 1402 X I Objsec

Address 1401

Testing 87N may cause operations of 87, 49-1, or49-2. If this occurs, Addresses 1601 (87), 2401 (49-1), and 2501 (49-2) can be set to Off to disable theelements. After testing 87N, these addresses mustbe reset to the desired values.

Programming for Trip Relay 1 – All 87N Tests

Program Trip Relay 1 to include Event “5821Restricted ground fault: General Trip ”. (Thedefault setting is sufficient.) Use this setting for all87N tests. Program Trip Relay 1 for the originalsetting after 87N testing is finished.

Test 42. Pickup and Dropout of 87N:Address 1903

IC

IB

IA

Ic

Ib

Ia


I1

TripContact 1

W1

W2

I1

1D1

1D2

2D1

2D2

INb

INa

W3 notshown

* I1 ON fortestingAddress1925

*I1 OFF fortestingAddress1927

or

STOP

START *Timer

5B1

5B2ContactMonitor

5B3

5B4

Connect I1 toINb if Address7807 (CTB) isassociatedwith 87N.

Connect I1 toINa if Address7806 (CTA) isassociatedwith 87N.


Connect the 7UT513 as shown in Figure 38, usingthe proper connections according to Addresses7819, 7806, and 7807. Turn Off the timer for thistest. Use the contact monitor. The timer is neededin the next test.

A trip contact is monitored in the steps below while87N pickup and dropout are tested. Monitoring a tripcontact is recommended because 87N is thenverified from input to important outputs. The timedelay of 87N tripping – Address1925 – must beaccommodated as the current is ramped up to testpickup. Likewise, the dropout delay – Address 1927– must be considered as the current is decreased tocheck dropout. If either of these delays isexcessive, the test can be easily adapted. Pickupand dropout of 87N could be tested with visualinspection of an LED programmed for Event nm5816 Restricted gnd fault: Pickup . Addresses1925 and 1927 would not effect the LED. The LEDwould have to be reprogrammed to the originalsetting after the test was completed.

1. The pickup current of 87N should be [Address1903 X INRGFWx] or [Address 1903 X IOBJRGF].Slowly increase the current until the contact ofTrip Relay 1 closes. Record the pickup currentat contact closure. Record other contact andLED operations.

2. Dropout/Pickup of 87N should be less than 80%.Slowly reduce the current until the contact drops

7UT51 v3

78 PRCM-1108A-0199

out. Record the current at dropout. Recordchanges of contacts, LEDs, and the LCD.

3. Turn Off the current. Reset the LEDs and LCD.

Note: Keep the 7UT513 connections for tests 43-45.

Expected Results:


The pickup current at contact closure should bewithin +/- 5% of [Address 1903 X INRGFWx] or[Address 1903 X IOBJRGF].

The dropout current at contact opening should bewithin [68% and 80%] of the tested pickup current.


For the default programming, all trip contacts shouldclose, contacts of Signal Relays 1 and 8 shouldtoggle, and LEDs 1 and 7 should light, when 87Ntrips. When 87N drops out, the contacts shouldreset and the LCD should display “RGF Gen. Fl t”and “RGF Gen. Trip ”. The LEDs should havememory.

Test 43. Time Delay of 87N Tripping:Address 1925

If Address 1925 = 0.00 seconds , skip to the nexttest unless Address 1901 = Off or Block Tripping inany setting group, or discrete inputs control theoperational status of 87N. Otherwise, perform thistest.

Use the same connections for the 7UT513 as in test42 (Figure 38). Connect the current sourceaccording to Addresses 7819, 7806, and 7807. TurnOn the timer. The settings for the timer are given inthe steps below.


2. Set the current source for a value that willprovide a solid pickup of 87N, based on theresults from Test 42. Current equal to twice thepickup value is good.

3. If Address 1925 is infinite (+*) seconds ,continue to Step 4. Otherwise, skip to Step 7.


5. Verify the timer does not stop, and no othercontacts or LEDs programmed for the tripping of87N operate. (Action from the pickup of 87N isproper.)

6. Turn Off the current, and reset the LEDs andLCD if applicable. Keep the connections, test-set settings, and 7UT513 settings if test 44 is tobe done. End of test.


8. Suddenly apply the current until 87N trips, thenturn Off the current.

9. Record the pickup time of 87N plus the outputcontact.

10. Repeat steps 8 and 9 two or more times, toobtain a pickup timespread for 87N plus contact.

11. If Address 1925 = 0.00 seconds is the desiredsetting, end of test. Keep the connections, test-set settings, and 7UT513 settings if Test 44 is tobe done. Otherwise, continue.




15. Keep the connections, test-set settings, and7UT513 settings if Test 44 is to be done.

Expected Results:

With Address 1925 = 0.00 seconds , the resultsindicate the inherent tripping time of 87N. Expecttimes in the range of [35 to 45] ms at 2 times pickup.

The pickup times from Step 10 (1925 = 0.00seconds ) must be subtracted from the pickup timeof Step 13 (1925 = desired setting) to obtain thetested value for Address 1925. The accuracy ofAddress 1925, with the timer accuracy included, isthe larger of +/- 3% or +/- 10 ms . The pickuptimespread of 87N (without delay) plus contact mustbe considered, though the spread should be tight attwo times pickup.

The pickup timespread of 87N plus contact can adderrors and uncertainty to the results. If the user isnot satisfied with the calculated value for Address1925, the “=Network Disturbances option in theWinDIGSI software can be useful.

Obtain dialog with the 7UT513. Click onAnnunciation , then Annunciations Edit . SelectNetwork Disturbances , and Display . Display anevent associated with the testing. Subtract the timefor Event “5816 Restricted gnd fault: Pickup ” from

7UT51 v3

PRCM-1108A-0199 79

the time for Event 5821 Restricted ground fault:General Trip to get the delay in tripping caused byAddress 1925.

Operations of the contacts, LEDs, and LCD shouldbe consistent with those in Test 42, withconsideration given to the programming for TripRelay 1. Depending on Address 1925, the delaybetween the application of current and 87N trippingmay be noticeable.

Test 44. Status Control of 87N: Discrete Inputsor Address 1901

If the operational status of 87N is controlled by adiscrete input(s), Test 43 can be repeated with theinput in the opposite state, to verify the control isfunctioning. Also, if multiple sets of protectionsettings are used, and Address 1901 = Off or BlockTripping in any of these sets, Test 43 can berepeated with these settings to verify properoperation of 87N. Use only the desired setting forAddress 1925 if Test 43 is repeated.

Expected Results:

Address 1901 = Off and an input causing thecoming of Event “5803 >Block restricted groundfault protect ”, applied before an 87N trip, shouldhave similar effects. Either should effectively make87N nonexistent . If 87N is first tripped, and thenEvent 5803 is activated, the event should have noeffect.

The 7UT513 should remain in a tripped state with allcontacts, LEDs, and the LCD reflecting the 87N trip.If (1) the event is first activated, (2) current abovethe pickup of 87N is applied, and then (3) the eventis de-activated with the current still present, 87Nshould trip and provide outputs, LEDs, and an LCDdisplay in the normal fashion.

Address 1901 = Block Tripping and an inputcausing the coming of Event 5805 >Block trip ofrestricted ground fault , applied before an 87N trip,should have similar effects. Either should preventEvent 5821 Restricted Ground Fault: GeneralTrip from operating trip relays. Events 5816Restricted gnd fault: Pickup and 5817 Restrictedgnd fault:Gen Fault Detection should still becapable of operating trip relays. Events 5816, 5817,and 5821 should be uninhibited in operating LEDsand signal relays. For the default settings, the LCDshould read RGF Gen. Flt .

If Event 5821 is blocked from operating a trip relaybecause of Event 5805, and then Event 5805 isreleased, Event 5821 should remain blocked.

Applying Event 5805 after 87N has tripped shoulddo nothing. The event should be ignored.

Test 45. Trip Dropout after Reset of 87N:Address 1927

Use the same connections for the 7UT513 as in test42 (Figure 38). Connect the current sourceaccording to Addresses 7819, 7806, and 7807. TurnOn the timer. The settings for the timer are given inthe steps below.


2. Set the timer to start when the current is turnedOff , and stop when the Trip Relay 1 contacttransitions from Closed to Open .

3. Set the current source for a value that willprovide a solid pickup of 87N, based on theresults from Test 42. Current equal to twice thepickup value is good.

4. Apply the current to pickup 87N.



7. Repeat steps 4-6 two or more times todetermine a timespread for the dropout time of87N plus contact.

8. If the desired setting of Address 1927 = 0.00seconds , end of test. Otherwise, go to the nextstep.



Expected Results:

With Address 1927 = 0.00 seconds , the dropouttime of 87N plus the contact should be 35 ms +/- 10ms, for a current of [2 X pickup] suddenly dropped to0 amp. For most 87N pickup values, the dropouttimespread with Address 1927 = 0.00 secondsshould be tight (within a few milliseconds).

The dropout times from Step 7 (1927 = 0.00seconds ) must be subtracted from the dropout timeof Step 10 (1927 = desired setting ) to obtain thetested value for Address 1927. The accuracy ofAddress 1927, including the timer accuracy, is thelarger of +/- 3% or +/- 10 ms. The dropout

7UT51 v3

80 PRCM-1108A-0199

timespread of 87N (without delay) plus contact mustbe considered.

Contact, LED, and LCD operations should be thesame as in Test 42.

Test 46. Second Harmonic Restraint of 87N:Addresses 1910 and 1911

Perform this test only if Address 1910 = On.

IC

IB

IA

Ic

Ib

Ia


I1

TripContact 1

W1

W2

I1

1D1

1D2

2D1

2D2

INb

INa

W3 notshown

Connect I2 to onephase of windingassociated with 87N.Connect I2 polarity tophase input polarity.

or

5B15B2 Contact

Monitor5B35B4

Connect I1 to Inb

if Address 7807(CTB) isassociated with87N.

Connect I1 to INa

if Address 7806(CTA) isassociated with87N.

I2

(60Hz)

(60Hz)

(120Hz)


Use Figure 39 to connect the 7UT513. Connect I1(60 Hz) according to Addresses 7819, 7806, and7807. Connect I2 (120 Hz) to any one phase of thewinding associated with 87N. Connect the polarityof I2 to the polarity of the phase input. If 87N isprotecting a virtual object, I2 must be connected to aphase of W3. Refer to earlier figures for the 7UT513terminals corresponding to W3.

1. Set the magnitude of the Source 1, 60 Hzcurrent (I1) to meet all three conditions below,if practical. Conditions “a” and “b” are required,although the multiple in “a” does not have tobe 2.

(a) A solid pickup of 87N is required.I1 = [2 X 87N pickup] from test 42 is good.

(b) I1 ≤ 20 amps (4 amps for a 7UT513 with arating of 1 amp).

(c) I1 ≥75 ÷[(Address 1911 in decimal format) X(87NGround CT Ratio)]

The 87N Ground CT Ratio is the primaryrating of the CT divided by the CTsecondary rating: either 5 amps or 1 amp.

Condition “c” is actually given to make themagnitude of the 120 Hz current such avalue that the errors, if any, associated withthe harmonic restraint are the dominanterrors in this test.

If the calculation for “c” is greater than 20 amps(4 amps), I1 = 20 amps (4 amps) isrecommended.

2. Set the Source 2 current frequency for 120 Hzand the magnitude equal to: I1 X[Address 1911 in Decimal Format] X [87NGround CT Primary Rating] ÷[87N Phase CT Primary Rating ]

3. Apply only Source 1 current to verify 87Ntripping.

4. Turn Off Source 1. Reset LEDs.5. Simultaneously apply both currents.6. Observe the response of the 7UT51 and

simultaneously turn Off both currents.7. Repeat steps 5 and 6, slightly adjusting the

Source 2 current magnitude while the currentsare Off , until the minimum Source 2 currentmagnitude for restraint is found.

Expected Results:


% 2nd Restr. = ([120 Hz current from Step 7] X [87N Phase CTPrimary Rating] X 100%)÷([60 Hz current from Step 7] X [87N Ground CTPrimary Rating])

The result should be within +/- 10% of Address 1911(calculations done in decimal format). For example,if Address 1911 = 15%, the test results should bewithin [0.135 and 0.165] . If condition “c” in Step 1 ismet, the result should be within +/- 5% ofAddress 1911.

If 87N tripping occurs, operations of the contacts,LEDs, and LCD should be consistent with Test 42.

If harmonic restraint occurs, LEDs and contactsprogrammed to operate for 87N tripping should notoperate. After current is turned Off , an LCDmessage may appear. For the default settings, themessage is RGF Gen. Flt .

7UT51 v3

PRCM-1108A-0199 81

Test 47. Differential Current Stopping 2 ND

Harmonic Restraint of 87N: Addresses 1910and 1912

Perform this test only if Address 1910 = On.

1. Calculate [INRGFWx X Address 1912] or [IOBJRGF XAddress 1912].

2. If the value from Step 1 is less than or equal to18 amps, go to Option 1 . Otherwise, continue.

3. If the value from Step 1 is less than or equal to36 amps and the 87N Phase CT Primary Rating= 87N Ground CT Primary Rating, go toOption 2. Otherwise, continue.

4. If the value from Step 1 is greater than 36 ampsand the 87N Phase CT Primary Rating = 87NGround CT Primary Rating, change Address1912 so:[INRGFWx X Address 1912]or[IOBJRGF X Address 1912] ≈ 36 amps

Then go to Option 2. Otherwise, continue.

5. Change Address 1912 as indicated below, andgo to option 1.

[INRGFWx X Address 1912]or[IOBJRGF X Address 1912] ≈ 18 amps

Option 1:

Use the same 7UT513 connections as in Test 46(Figure 39).

1. Set the 60 Hz Source 1 current for about [0.8 XINRGFWx X Address 1912] or [0.8 X IOBJRGF XAddress 1912].

2. Set the Source 2 current frequency for 120 Hz.

3. Set the Source 2 current magnitude so that thepercentage of 2nd harmonic current, when theSource 1 current reaches [INRGFWx X Address1912] or [IOBJRGF X Address 1912], is muchgreater than the minimum restraint level(Address 1911). If I2 is the magnitude of theSource 2 current and I1 the magnitude of theSource 1 current, then:I2 >> I1X [87N Ground CT Primary Rating]X [Address 1911, Decimal Format]÷ 87N Phase CT Primary Rating

Note : Do not exceed the current limitations of the7UT513.


5. Verify that 87N did not trip.

6. Slowly increase the 60 Hz Source 1 current until87N trips.

7. Record the 60 Hz current.

8. Turn Off both currents and reset the LEDsand LCD.

Option 2:

IC

IB

IA

Ic

Ib

Ia


I2

TripContact 1

W1

W2

I1

1D1

1D2

2D1

2D2

1Nb

1Na

W3 notshown

or

5B15B2

ContactMonitor

5B3

5B4

(120Hz)

(60Hz)

ExampleConnectionsonly. AssumesCTA andwinding 2 areassociated with87N.

Figure 40 : Test 47 Connection Diagram

Use Figure 40 to connect the 7UT51. For clarity, thefigure is drawn as if 87N is protecting Winding 2, andCT A is associated with 87N. Adapt the connectionsas necessary. The important points in Figure 40 arethe polarity of I1 connects to the polarity of the7UT513 current input for the 87N Ground CT(terminal 2D1 in the figure). The non-polarityterminal of the 87N Ground CT current inputconnects to the polarity of the 7UT513 current inputfor 87N Phase CT (Terminal 2D2 to 2B1 in thefigure). Finally, the non-polarity terminal of the 87NPhase CT current input (Terminal 2B2 in the figure)connects to the non-polarity terminal of the source 1current. These connections simulate an internalfault. The Source 2 current (120 Hz) connects to adifferent phase of the winding associated with 87Nbecause of 7UT513 current limitations.

1. Set Address 1911 = 10%.

2. Set the 60 Hz Source 1 current for about [0.4 XINRGFWx X Address 1912] or [0.4 X I OBJRGF XAddress 1912]. (Since the current is injected inthe ground input and the phase input – both in a

7UT51 v3

82 PRCM-1108A-0199

positive direction – the test current is doubled informing the differential current.)

3. Be sure current Source 2 is connected to adifferent phase than current Source 1.

4. Set the Source 2 current frequency for 120 Hz.

5. Set the Source 2 current magnitude equal to 18amps.


7. Verify that 87N does not trip.

8. Slowly increase the 60 Hz Source 1 current until87N trips.

9. Turn Off both currents and reset the LEDs andLCD.

10. Reset Address 1911 to the original value.

Expected Results:

Option 1:

The 60 Hz Source 1 current at which 87N trips inStep 7 should be within +/- 5% of [INRGFWx XAddress 1912] or [IOBJRGF X Address 1912].

Contact, LED, and LCD operations should be thesame as in Test 42 when 87N trips.

Option 2:

The 60 Hz Source 1 current at which 87N trips instep 8 should be within +/- 5% of [0.5 X INRGFWx XAddress 1912] or [0.5 X IOBJRGF X Address 1912].

Contact, LED, and LCD operations should be thesame as in Test 42 when 87N trips.

Notes about Testing the Extended Tripping Areaof 87N - Critical Angle for Restraint

In classical, overcurrent, restricted ground faultprotection schemes, 87N trips if the torque in theequation below is positive. The 87N restrains whenthe torque is negative.

Torque = 3I0* X 3I0** X cos Θ

In this equation, 3I0* is the current from thetransformer ground CT, 3I0** is three times the zerosequence current from the transformer phase CTs(the vector sum of the three phase currents), and Θis the angle between the two currents. Byconvention, the reference for the currents is adirection towards (or into) the transformer.

The cosine term defines the trip and restraint areas.For [-90° < Θ < 90°], the cosine term is positive, and

87N trips. For [90° ≤ Θ ≤ -90°], 87N restrainsbecause the cosine term is negative or zero. For aninternal fault, both 3I0* and 3I0** flow into thetransformer; therefore, Θ is 0° or nearly so. Thetorque is a maximum positive. For an external fault,3I0** is in a reverse direction, and Θ is in theneighborhood of 180°. The torque is a maximumnegative (or restraint).

For testing purposes (and most purposes becauseof phase-angle symmetry), the region of [0° ≤ Θ ≤180°] is of interest.

The 7UT513 employs a different algorithm thatextends the trip area beyond 90° when Address1904 > 90°. When Address 1904 = 90°, 87N has thesame operating characteristic as the classical 87N.

The 7UT513 recognizes a fault condition – internalor external – when the restraint current or differentialcurrent exceed certain thresholds.

IRESTRGF = Ia + Ib + Ic + 3I0*(Ia, Ib, and Ic are the phase currents for 87N)

IDIFFRGF = 3I0* + 3I0** (vector sum)

Once a fault is detected, further analysis is done todetermine if a trip should be issued.

The 87N algorithm calculates a “stabilizationcurrent,”

ISTAB = 3I0* – 3I0** − 3I0* + 3I0**

If ISTAB is negative or zero, a trip is issued ifinequality (1) is satisfied:

3I0* ≥ [Address 1903 X I NRGFWx] or[Address 1903 X I OBJRGF] (1)

The stabilizing current is negative or zero when 3I0*= 0 amp, 3I 0** = 0 amp, or [0 ° ≤ Θ ≤ 90°]. The lastcondition is a clear indication of an internal fault, anda trip is issued if the minimum pickup of 87N(Address 1903) is exceeded by 3I 0*. The conditionof 3I0** = 0 amp is simulated in Test 42. Thecondition of Θ = 0° is checked in Test 47. Notice87N of the 7UT513 responds like the classical 87Nwhen [0 ° ≤ Θ ≤ 90°].

If ISTAB is positive, another inequality is used in thetrip decision. If inequality (2) is satisfied, a trip isgiven:

7UT51 v3

PRCM-1108A-0199 83

3I0* − [k X ISTAB] ≥ [Address 1903 X I NRGFWx] or[Address 1903 X I OBJRGF] (2)

Where k is a stabilization factor corresponding toAddress 1904. The factor is discussed later.

The stabilizing current is positive when [90° < Θ ≤180°]. Angles close to 180° when 3I0* ≈3I0**clearly indicate an external fault. However, anglesnear 90° could result from an internal fault with CTsaturation distorting the current angle. This isespecially true if 3I0* is significantly greater than3I0**. The effect of the operating quantity {3I 0* −[k X ISTAB]} is to extend the trip area beyond 90°.The amount of the extension depends on k (whichdepends on Address 1904) and the ratio [3I0* /3I0**]. The extended trip area increases as the ratioincreases.

For more information, please refer to A NewApproach for Transformer Ground DifferentialProtection, by Dr. Tevfik Sezi, Siemens PowerTransmission and Distribution, Raleigh, NorthCarolina. For Test 48, the ratio [3I0* / 3I0**] = 1 is ofinterest. The value of k depends on Address 1904.

With 3I0* = 3I0**:

ISTAB = 2 X 3I0* X {sin ( Θ /2) −cos ( Θ/2)}

Inequality (2) becomes

3I0* X {1 − [2 X k X (sin Θ/2 −cos Θ/2)]} ≥ [Address1903 X INRGFWx or IOBJRGF]

If 3I0* = 2 X [Address 1903 X I NRGFWx or IOBJRGF], theinequality can be expressed:

sin ( Θ/2)−cos ( Θ/2) ≤ (0.25 / k) (3)

If 3I0* = 3 X [Address 1903 X I NRGFWx or IOBJRGF], theinequality can be expressed:

sin ( Θ/2)−cos ( Θ/2) ≤ (0.333 / k) (4)

Tables 11 and 12 give the maximum Θ, accurate towithin +/- 0.1°, at which inequalities (3) and (4) aresatisfied, for different settings of Address 1904. Thevalues of k are those used by the 7UT513 for theAddress1904 selected.

7UT51 v3

84 PRCM-1108A-0199

Table 11: Maximum Θ for 87N trippingwith 3I0* = 3I0** = [2 X Address 1903 XINRGFWx or IOBJRGF] andk-Values for Address 1904

Address1904

Value of kassociated withAddress 1904

Maximum Θfor 87N Trip

130° 1.03372 109.7°120° 1.36603 104.9°110° 2.03603 100.0°100° 4.05657 95.0°90° ∞ 90.0°

Table 12: Maximum Θ for 87N trippingwith 3I0* = 3I0** = [3 X Address 1903 XINRGFWx or IOBJRGF] andk-Values for Address 1904

Address1904

Value of kAssociated withAddress 1904

Maximum Θfor 87N Trip

130° 1.03372 116.4°120° 1.36603 109.9°110° 2.03603 103.3°100° 4.05657 96.7°90° ∞ 90.0°

In Test 48, two current sources are set up tosimulate an external fault. The current source for3I0** is set 180° out of phase with the current sourcefor 3I0* to simulate the external fault. To allowinequality (3) to be used, 3I0* = 3I0** = [2 XAddress 1903 X I NRGFWx] or [2 X Address 1903 XIOBJRGF]. If preferred, the multiple of 3 can be usedinstead, or in addition, to allow inequality (4) to beused. After the security of 87N for an external faultis checked, the magnitudes of 3I 0* and 3I0** areheld constant as the angle of 3I0** is decreased untila trip occurs. The angular difference between 3I0*and 3I0** is compared to the expected values inTable 11 or Table 12. This step checks theextended trip area of the 7UT513 (Address 1904).

Test 48. 87N Security for External Faultsand Critical Angle for Restraint:Address 1904

IC

IB

IA

Ic

Ib

Ia


I1

TripContact 1

W1

W2

I1

1D11D22D12D2

INb

INa

W3 notshown

Connect I2 toone phase ofwindingassociated with87N. ConnectI2 polarity tophase inputpolarity.

or

5B15B2 Contact

Monitor5B35B4

Connect I1 to INbif Address 7807(CTB) isassociated with87N.

Connect I1 to INaif Address 7806(CTA) isassociated with87N.

I2


Use Figure 41 as a guide to connect the 7UT513.The polarity connections are critical. Connect thepolarity of Current-Source 1 to 7UT513 terminal 1D1(Address 7807 associated with 87N) or terminal 2D1(Address 7806 associated with 87N). ConnectCurrent-Source 2 to any one phase of the windingcorresponding to 87N. The polarity of Current-Source 2 must be connected to the polarity of the7UT513 current input.

7UT51 v3

PRCM-1108A-0199 85

Security for External Faults:

1. Set Current-Source 1 for [m X Address 1903 XINRGFWx] or [m X Address 1903 X I OBJRGF] at 0°and 60 Hz, where m = 2.

2. Set Current-Source 2 at 180°, 60 Hz, and:Magnitude =

([Current-Source 1 Magnitude] X [87N Ground CTPrimary Rating]) ÷(87N Phase CT Primary Rating)

3. Apply both currents Simultaneously.

4. Verify that 87N does not trip.

Metering Validation:

5. View the RGF metering from the LCD byfollowing steps 6-16. Items in bold are keys onthe front of the 7UT513.

6. Press Direct Addr , 4181, then Enter. Thedisplay should read 4181 Test RGFMeasuring?

7. Press Yes.

8. The display should read 4181 Test RGF IPhA =xxx% . The value should equal the currentapplied to Phase A of the winding associatedwith 87N. The value should be in percentage of5 amps (or 1 amp ).

9. Continue to press No to view IPhB, IPhC, (IPhB− IPhA), and (IPhC − IPhA).

10. 3I0* is the current in the 87N ground CT input, inpercentage of 5 amps (1 amp ).

11. 3I0** is three times the zero sequence current inthe phases of the winding being protected,which is equal to the vector sum of all of thephase currents. Since only one phase is loaded,3I0** should equal the phase current.

12. 3I0* − I0** = x° is the phase angle between 3I0*and 3I0**. For the external fault, the angleshould be 0°.

13. Diff = xxx% is the RGF differential current. Thevalue should be less than 2%.

14. Restr = xxx% is the RGF restraint current.

15. When finished reading the LCD metering, pressDirect Addr, 4801 , and Enter . The displayshould read 4801 Stop Test – Finish?

16. Press Yes. The display should read 4801 StopTest – Test Finished .

17. View the RGF metering from WinDIGSI followingsteps 18 - 24.

18. Obtain dialog with the 7UT513.

19. Click on Test .

20. Click on 4100 Commission Tests and Display .

21. Click on 4181 Meas./ind. of current -/angl valof RestrGnd Flt and Execute .

22. Click on Yes.

23. All of the RGF metering values should be in theTest Results box. The values should be nearlythe same as those from the LCD.

24. When finished viewing the metering inWinDIGSI, continue to click on Close to exit.

Critical Angle for Restraint (Extended Trip Area):

25. Depending on the value of m in Step 1 andAddress 1904, refer to Tables 11 and 12 todetermine the expected maximum Θ.

26. Slowly decrease the angle of Current-Source 2(from 180° towards 0°) until 87N trips. (Theangle of Current-Source 1 can be increasedinstead, but changing Source 2 is easierbecause Θ is then the angle of Current-Source2.)

27. Record the angle difference between the twocurrent-sources. This is the tested value for themaximum Θ.

28. Record contact and LED operations.

29. Turn Off the current and record the LCD.


31. If desired, the value of m can be changed to 3,and steps [1-4] and [25-30] can be repeated,although not required.

Expected Results:

The tested value of maximum Θ in Step 27 shouldbe within +/- 1.5° of the Maximum Θ for 87N Trip,corresponding to Address 1904 used in the test, inthe applicable Tables 11 and 12 above.

With the default settings, there should be nooperations of contacts or LEDs when the externalfault is simulated. As the angle is decreased, Event“5817 Restricted gnd fault:Gen fault detection ”should operate well before 87N trips. This resultsfrom the differential current exceeding the thresholdfor fault detection. Event 5817 will only benoticeable if the event is programmed to contacts orLEDs. (The event is not included in the defaultsettings.) When 87N trips at maximum Θ, contact,LED, and LCD operations should be consistent withTest 42.

7UT51 v3

86 PRCM-1108A-0199

Program Trip Relay 1 for the desired, in-servicesettings.

Setting Verification after Electrical Testing

Although instructions are given throughout theprocedure to reset addresses or programming backto the original, desired values after the tests, acomplete down-loading of all of the intended 7UT51settings is recommended when the electrical testshave finished. This will prevent unintended settingswhen the 7UT51 is placed in-service. Alternatively,a thorough check of the settings should be madeafter the electrical tests have been completed andbefore the 7UT51 is placed in-service.

7UT51 v3

PRCM-1108A-0199 87

Control Wire, CT, and Relay Installation

Primary Equipment Check

Prior to starting any of the control installation work,all primary equipment should be installed, allmounting of boxes, cabinets, etc. and all conduits inplace. All external control cable should be pulled.Check nameplate of the transformer, terminal blockmarkings, phasing, etc., to ensure that the drawingsare in agreement.

Electrical Drawings Wire Check

Each piece of primary equipment should be wirechecked and compared against the electricaldrawings.

Review and check the elementary wiring, functional,and one line diagrams. Verify that currents for allpower paths (both load and short circuit) and trippingfor each source are included.

CT Installation

As in any control installation, the wiring and controldiagrams and all applicable instruction manualsmust be thoroughly reviewed and understood beforeany work begins. This is especially true for theinstallation of a CT in a differential transformerprotection scheme. Power transformers may haveboth a current magnitude and phase shift associatedwith the operation.

Check ratio selection. Generally, the high side of theCT is selected to match the full load rating of thewinding.

With the Siemens numerical differential relay, all CTsecondary circuits can be connected in wye;however, the Siemens relay can be applied inexisting protection schemes having delta and wyeconnected CTs. Ratio matching and phase shift tothe various power transformer and CT ratios and ofthe phase displacement, according to the vectorgroup of the protected transformer displacement, arecompensated for numerically (see Matching Factorin the Definition of Terms section).

The input currents are converted in relation to thepower transformer rated current. This is achieved byentering the rated transformer data, such as ratedpower, rated voltage, and rated primary current ofthe CTs, into the protection unit.

Interposing Transformers

When the power rating of the windings differ stronglyfrom each other (more than the factor four),interposing transformers are recommended. If aninterposing transformer set is used for one winding,the transformation ratio of the interposingtransformer must be considered when entering thesetting for this winding. This is done by dividing theactual primary CT rated current by the winding ratioof the interposing transformer. The result is enteredin Address 1104 or using WinDIGSI, in the Settingmenu, Transformer Data section.

Once the vector group has been entered, theprotection unit is capable of performing the currentcomparison according to fixed formulas.

Relay Installation

Refer to the 7UT51 v3 Protective Relay InstructionManual for installation instructions. See Figures 42and 43 for connection examples of the relayinstallation with the following configurations:

Two Winding, Delta-Wye Transformer

Three Winding, Delta-Wye-Delta Transformer






7UT51 v3

88 PRCM-1108A-0199

7U T 51 R e la ya

A

b

B

c

C

Primary

Secondary

IA

IB

IC

Ia

Ib

Ic

3A1 3A2

2A1 2A2

1A1 1A2

3B1 3B2

2B1 2B2

1B1 1B2

Figure 42: Two-Winding, Delta-Wye Transformer

Primary

Secondary

Tertiary 7UT513

a

a '

A

b

b '

B

c

c '

CI

A

IB

IC

Ia

Ia '

Ib

Ib '

Ic

Ic '

3 A1 3 A2

2 A1 2 A2

1 A1 1 A2

3 B1 3 B2

2 B1 2 B2

1 B1 1 B2

3 D 1 3 D 2

2 C 1 2 C 2

1 C 1 1 C 2

Figure 43: Three Winding, Delta-Wye-DeltaTransformer

7UT51 v3

PRCM-1108A-0199 89

Commissioning Tests

Physical Inspection

Inspect all cables, junction boxes, circuit breakers,etc., for proper wiring, shorting type terminal blocksat proper locations, tight connections (screw headsmust be tight against wire). Check that shortingscrews are removed from CT blocks that will be inservice. Inspect boxes, switches, and relays for anymaterial such as wires, screws, lugs, or tags thatcould short or ground the circuit. Visually wire-checkall current circuits.

Check auxiliary switches for connections, wipe, andadjustment per manufacturer's instructions,particularly the operating relation with respect tomain blade make and break.

After the acceptance tests have been completed andthe relay is installed with the permanent settingsapplied and tested, the commissioning tests andchecks can be performed.

Installation Test Procedures

For test procedures, refer to the Acceptance Testingsection and perform only the tests required to checkthe settings and control to be used in the specificfield application. Prior to installation, completetesting of the discrete inputs, signal contacts, andtrip contacts is recommended. This will reduce theoperational checking of the transformer protection tosimply checking the CT connections, 7UT51 inputconnections, and wiring of the output contacts.

Operational Checks

Operational checks are performed after wirechecking is complete.

If trip test switches are installed in the circuit, theseinitial checks are performed with the trip testswitches in the Open position. If no trip testswitches are installed, disable/block the relay tripoutput.

1. Energize the main DC power supply to the relay.

2. Check for proper DC polarity and magnitude foreach control circuit.

3. Reset all alarms and annunciators.

4. Verify that all relay and lockouts are reset.

5. Check that the matching k factor is correct.

Operate each relay contact to verify correct target,lockout relay (86), and alarm. Reset after each trip.Operate the differential function by passing currentthrough the circuit from each set of CTs. Check andverify the other protective function targets.

Once the relay operations are verified, the majorequipment such as circuit breakers and air breakswitches can be checked for proper operation. Withthe 86 relay in the Trip position, close each testblade separately. When the test blade is closed, itscorresponding piece of equipment will trip.

Once tripped, check and verify all interlocks forcorrect operation.

After verifying all tripping from the lockout (86)through the test blades, all external tripping of the 86relay is performed.

An overall operational test should be performed togive a final system check. No part of the controlscheme should be assumed correct. Test everyinput, output and function to verify that it operatesindependently and also in conjunction with the totalscheme.

Once all checks are complete, check for zero (0)voltage across the relay trip test switches with a DCvoltmeter.






7UT51 v3

90 PRCM-1108A-0199

Energizing the Transformer

When all control and current circuits have beenchecked, verified, the transformer is ready to beenergized.

Prior to energizing the transformer, all relayprotection is placed in service. All secondary testsets and equipment must be removed. All CTsconnected.

In-Service Readings

In-service readings are taken to ensure systemreliability and security after the transformer isenergized and loaded.

• Read and record magnitude and phase anglereadings in all leads and windings.

• Check balance with meter. Trace anyabnormalities.

• Verify all measurable quantities (inputs) throughthe relay.

Operational Measured Values

Check the steady state rms operating values toverify that the relay is functioning properly. Thisinformation is accessed directly in Address Blocks5700 and 5900 and compared with actual knownvalues. See the Accessing Data section. Comparethe known current values with the displayed testcurrents.

Figure 44: WinDIGSI Metering Data Screen

Measured Test Currents

Read the relay measurement of currents and phaseangles through test Address 4101.

Compare the known current values with thedisplayed test currents. If deviations occur thatcannot be explained by tolerances, recheckconnections and test arrangement and repeat.

If the values are not correct, wrong polarity or phaseinterchange at Side 1 is usually the cause:

Check connections. Repeat test by renewedmeasurement request

See the Accessing Data section for more detailedinstructions.

Waveform Capture during Test Fault Record –Address 4900

Recording a test fault record is especially importantfor use on transformers where large inrush currentscan be produced by transient saturation of thetransformer iron. Since a large inrush current mayhave the same effect as a single ended infeed fault,energizing the power transformer several timeschecks the effectiveness of the inrush stabilization.

Since the pick up signal of the relay is not stabilized,the inrush current will start fault recordingautomatically, provided that Address 7402 WaveTrig is set to Trig with Pickup . Otherwise a faultrecord is only stored if the relay has tripped. A faultrecord can always be triggered via a discrete inputprovided this is allocated.

The effectiveness of the inrush stabilization can bedetermined from the recording of the differentialcurrents and the harmonic contents. If necessary,the inrush current stabilization effect can beincreased in Address 1611, when trip occurs, orwhen the recorded data show that the secondharmonic content does not safely exceed the setstabilizing threshold set in Address 1611. A furthermethod to increase inrush stability is to set the crossblock function (Address 1612) effective or toincrease the duration of the cross block function.

7UT51 v3

PRCM-1108A-0199 91

Figure 45: Waveform Capture of NormalLine Current

Perform a manual start of the waveform capturerecord (for analysis of the steady state rms currentor test current) in Address Block 4900.

The data can then be downloaded to a PC foranalysis, and verification that the relay is processingall inputs as required by the application.

See the Data Available section for instructions andexamples.

Installation of 7UT51 Relay in Existing Circuit

The installation of the Siemens 7UT51 relay in anenergized circuit can be perform without disturbingthe existing system.

The following must be completed before the relaycan be fully functional in the circuit:

1. Settings applied

2. Acceptance/Installation tested (out of circuit)

Once all of the necessary and applicable testing hasbeen performed on the relay, the relay can beprepared for installation and testing.

Note: Be sure that trip circuits are disconnectedfrom the relay trip contacts and are leftopen-circuited. Do not connect any of therelay outputs to any external breaker failuredevices.

If test switches are available, place allrelated switches in the Test position.

Read and record magnitude and phase anglereadings in all leads and windings.

Perform a manual Waveform capture throughAddress Block 4900 and verify the primary andsecondary waveforms using WinDIGSI and DIGRA.

Check balance with meter. Trace any abnormalities.

Verify all measurable quantities (inputs) through therelay. Read the relay measurement of currents andphase angles through Test Address 4101.


When assessing the currents, note that thedifferential and stabilizing values are referred to therated current of the transformer winding.

The value of differential value should be negligibleagainst the magnitude of the line currents. Thestabilizing (restraint) value should be approximatelytwice the line current value.

Take relay out of Test mode through Address 4800.

Output Connections

With test switches in the test position, proceed withmaking all trip and signal output connections.

Since the relay is installed in an energized circuit,operational checks of each output cannot beperformed; however, all outputs from the relay arechecked prior to installation and all control circuitry ischecked upon installation or subsequent outages.

Note: A complete functional check for all trip andsignal outputs should be performed during thenext available outage.

7UT51 v3

92 PRCM-1108A-0199

Putting the Relay into Operation

All setting values should be checked again, in casethey were altered during the tests. Particularlycheck that all desired protection functions have beenEnabled in the Address Block 7800 and that alldesired protection functions have been switched Onin the corresponding Settings menu.

Stored indications on the front plate should be resetby pressing the Target Reset on the front so thatfrom then on, only real faults are indicated. Fromthat moment, the measured values of the quiescentstate are displayed. While pressing the Resetbutton, the LEDs on the front will light up (except theBlocked LED ); thus, an LED test is performed at thesame time.

Delete stored annunciations and counters go toAddress Block 8200:

• Enter the password (000000).

• 8201 resets LED memory.

Using WinDIGSI the LED reset is found under:Options\Device\Reset LEDS.

• 8202 deletes the operational buffer storage.Using WinDIGSI, deleting the operational bufferis founder under:

Control/ Resetting Stored Data / 8202 - ResetEvent Log/ or /8203 – Reset Trip Log .

• 8203 deletes the fault annunciation bufferstorage.

Using WinDIGSI, deleting the operational bufferis founder under:Control/ Resetting Stored Data / 8202 - ResetEvent Log / or / 8203 – Reset Trip Log .

• Press the Target Reset on front panel.

Push the Event key on the front of relay. Thedisplay shows the beginning of the annunciationblocks. Thus, it is possible that the measuredvalues for the quiescent state of the relay can bedisplayed. These values had been chosen duringconfiguration under the Addresses 7105 and 7106.

All terminal screws, even those not in use, should betightened.

Check that all modules are properly inserted. Thegreen LED should be illuminated and the red LEDshould not be illuminated.

Close housing cover.

Note: Housing cover must be on relay for properoperation.

Place test switch in the Operating position.

After all readings are taken and found to be correct,the relays can be are placed in service.

Check that all protection is in service and that allindicating lights, targets, and equipment are resetand normal before leaving.

7UT51 v3

PRCM-1108A-0199 93

Routine Testing of System

Relay Integrity

Routine checks of the relay characteristics or pickupvalues are not necessary, as they form part of thecontinuously supervised firmware programs.

The relay is self-monitored and problems within therelay are automatically annunciated. If a problemwithin the relay is detected, the relay will block itselfand the red LED Blocked light will be lit and LCDwill read Equipment Fault .

Operational Measured Values

During periodic checks, the steady state rmsoperating values can be read out at any time toverify that the relay is functioning properly. Thisinformation can be accessed directly in AddressBlocks 5700 and 5900 and compared with actualknown values.

It is not necessary to perform testing during anoutage since most of the relays functions can bechecked by putting test switches in the Test positionand blocking all outputs from the relay; however,most operational wire checking and functionaltesting of the controlled devices will require anoutage.

Input Integrity

The inputs can be periodically checked byperforming the following:

• Block tripping.

• Place test switches in Test position.

• Apply a DC voltage to each input (one at a time),preferably at a point that tests the largest sectionof control wiring, check that the relay functionsappropriately through LEDs, outputs, or otheralarms and event messages.

Output Integrity

During an outage, one method available to checkthe outputs is to program one input for external tripand program all outputs (signal and trip) for externaltrips up to ten (10) at a time. Then trip theperspective devices. This test would check theoutputs and operational wiring out to the controlleddevice.

Validate Metering

Testing the metering of the relay is the quickestmethod of determining if the relay in no longerfunctioning or that it is incorrectly connected. If therelay cannot correctly determine what is beingapplied to its inputs, it can no longer protect.

Measured Test Currents

Perform inservice (or test current) relaymeasurements of all currents and phase anglesthrough Test Address 4101.


When assessing the currents, note that thedifferential and stabilizing values are referred to therated current of the transformer winding.



Before performing work on currenttransformer wiring, always short-circuit thesecondary of all the current transformers.



This test will trip controlleddevices.

7UT51 v3

94 PRCM-1108A-0199

During normal operation or through-fault testing, thevalue of differential current should be negligibleagainst the magnitude of the line currents. Thestabilizing (restraint) value should be approximatelytwice the test or line current value.

When the relay is in test mode, the differentialprotection and the restricted ground fault protectionare not effective, even when they are switched On.Take the relay out of test mode after the tests havebeen completed.

Waveform

Note : If the routine checks are performed duringEnergized conditions or with test switches inthe Test position, initiate manual starting ofthe record in Address Block 4900 to read lineor test current.

Note: If the routine checks are performed during anoutage or with test switches in the Testposition, a switching test or fault test can beperformed. See the Commissioning section ofthis manual.

Download the captured waveform to a PC foranalysis, and verification that the relay is processingall inputs as required by the application.

Once the waveform has been captured, view it usingWinDIGSI and DIGRA software.

Putting the Relay into Operation

All setting values should be checked again, in casethey were altered during the tests. Particularlycheck that all desired protection functions have beenprogrammed in the Address Block 7800 and that alldesired protection functions have been switched On.

Stored indications on the front plate should be resetby pressing the Target Reset on the front so thatfrom then on, only real faults are indicated. From

that moment, the measured values of the quiescentstate are displayed. While pressing Reset .If testing is performed during an outage or the testswitches are in the test position, all terminal screws,even those not in use, should be tightened.

Close housing cover.

Note: Housing cover must be on relay for properoperation.

If test switches are in the Test position, place in theOperating position.

After all readings are taken and found to be correct,the relays can be are placed in service.

Check that all protection is in service and that allindicating lights, targets, and equipment are resetand normal before leaving.

Information to a SCADA System during TestOperation – Address Block 8300

When the relay is connected to a central storagedevice or localized substation automation systemand VDEW/ZVEI is used, the information transmittedto the central computing system can be identified as“Test Operation ” for all annunciations, messages,and measured values occur while the relay is tested.Thus, these messages can be distinguished fromthose that occur during real operation.

In order to accomplish this switch over, AddressBlock 8300 is available, provided the VDEW/ZVEIprotocol has been chosen during configuration of theserial system interface; Address 7221 and/or 7222VDEW Compatible or VDEW Extended.

Note: Switch Address 8301 back to Sys. Test Offafter completion of testing.

7UT51 v3

PRCM-1108A-0199 95

Fault Data and Analysis ToolsFront Panel Alarms

Addresses 7107 and 7108 can be set to DisplayInformation on the latest fault event. Once themessage is acknowledged with the Reset key or viaremote reset , the selected display for Addresses7105 and 7106 will appear.

The LEDs will be lit depending on how they weremarshalled in Address block 6300 (assuming thecorresponding function is Enabled and On).

Remote warnings will also be initiated if utilized.

Fault Analysis Data

The sources available to analyze a fault event are asfollows.

Address 5100 - the Event Log which contains the50 most recent event messages, both operationaland fault messages, with older messagesoverwritten by newer messages.

Address 5200 – The Last Fault information (seeNote)

Address 5300 – The 2nd to Last Fault information(see Note)

Address 5400 – The 3rd to Last Fault information(see Note)

Note : Each fault log contains up to 80 fault relatedevent messages beginning with the pickup ofany active protection function and ending withthe dropout of that function. If necessary tomake room, the oldest fault log and/or oldestevent messages within a log may beoverwritten.

Each event message has three parts:1. The date and time of the event

2. A description of the event

3. An indication of whether the condition thattriggered the event is starting or ending .

Figure 46: Example of Fault Data

PC

The PC can communicate directly with the relay byentering the Dialog menu and choosing the Dialogmode with the protection device Direct . Data mayalso be accessed via a modem or SCADA system.Consult the WinDIGSI Instruction Manual or theWinDIGSI User’s Manual for detailed instructions.

The recorded waveform fault data can be viewedand analyzed by exporting (download) to a PC.Data for up to three faults is stored in the relay;however, the PC memory can store many. This datacan give valuable information on the simultaneouslycaptured data for all current inputs and up to fouruser-defined functions that report the status ofdiscrete-signal inputs.

7UT51 v3

96 PRCM-1108A-0199

The fault data is accessed by entering the Faultmenu. From the Fault menu:

1. Choose Fault Record .

2. A list of the fault instance recorded within theactual device or the device file will appear

3. Select the fault instance.

4. Choose Options.

5. Choose the type of graph desired: primaryvalues, secondary values, or normalized values

6. Click DIGRA.

7. From this point on there are several options forviewing the data and printing the data. Consultthe WinDIGSI Instruction Manual or theWinDIGSI User’s Manual for detailedinstructions.

Saving/Archiving Fault Data

Using the WinDIGSI software, all faults present inthe relay can be completely transmitted to thecomputer. Each fault is saved in a separate file.Select the option PD->File in the Fault menu. Youwill be asked to confirm your intention. You canstore as many event messages as necessary.

Resetting/Clearing Buffers and Targets

To reset the Event or Fault logs:

1. Enter the password (000000).

2. 8201 resets LED memory.Using WinDIGSI, the LED Reset is found under:Options\Device\Reset LEDS.

3. 8202 deletes the operational buffer storage

4. Using WinDIGSI, deleting the operational bufferis founder under:Control/Resetting Stored Data/8202 – ResetEvent Log/ or /8203 – Reset Trip Log.

5. 8203 deletes the fault annunciation bufferstorage.

6. Using WinDIGSI, deleting the operational bufferis founder under:Control/Resetting Stored Data/8202- ResetEvent Log / or / 8203 – Reset Trip Log.

7. Press the Target Reset on the front panel.

7UT51 v3

PRCM-1108A-0199 97

Address Index

1000

1100 ................................................ 8, 22, 371102 .......................................................... 171104 .................................. 17, 22, 43, 76, 871105 .................................................... 17, 361106 .................................. 24, 36, 37, 39, 411107 .............................................. 43, 47, 761108 .......................................................... 421121 .................................................... 17, 241124 .............................................. 17, 22, 761125 .................................................... 17, 361126 .......................................................... 241127 .......................................................... 761141 .......................................................... 241144 .................................................... 22, 761146 .......................................................... 241147 .......................................................... 761401 .......................................................... 761402 .................................................... 22, 761601 ...................... 20, 24, 48, 49, 50, 60, 761603 ............................ 24, 27, 32, 44, 45, 541604 ..........25, 26, 27, 28, 29, 30, 31, 45, 551606 .......................................................... 451607 .................................................... 44, 451608 .................................................... 45, 461611 .............................................. 31, 33, 901612 .............................................. 33, 34, 901613 .............................................. 32, 33, 351614 .................................................... 32, 331615 ............................ 32, 33, 34, 35, 50, 511616 .................................. 23, 32, 33, 50, 511617 .............................................. 47, 48, 551618 .................................................... 46, 47162525, 26, 27, 28, 29, 30, 31, 34, 35, 46, 47, 481626 .............................................. 28, 29, 301627 ........................................ 26, 27, 30, 311900 .......................................................... 141901 .............................................. 76, 77, 781903 ........................................ 76, 77, 82, 831904 .............................................. 82, 83, 841910 .................................................... 79, 801911 .............................................. 79, 80, 811912 .................................................... 80, 811925 .............................................. 76, 77, 781927 .............................................. 76, 78, 79

2000

2100 .......................................................... 152101 ...................... 27, 50, 60, 64, 65, 67, 702103 ...................... 61, 62, 63, 66, 67, 68, 712104 .................................. 61, 67, 68, 69, 702111 ........................................ 60, 61, 62, 642112 .................................................... 60, 61

2113 ..................................62, 63, 64, 65, 702114 .................................................... 60, 612115 .......................................................... 612118 .................................................... 66, 712121 ........................................ 62, 64, 67, 692400 .......................................................... 152401 ................27, 50, 52, 53, 54, 55, 60, 762402 ........................................ 51, 52, 53, 542403 ........................................ 51, 52, 53, 552404 .................................................... 51, 522405 .......................................................... 512406 .......................................................... 502500 .......................................................... 152501 ................27, 50, 52, 53, 54, 55, 60, 762502 .............................................. 51, 52, 532503 ........................................ 51, 52, 53, 552504 .................................................... 51, 522505 .......................................................... 512506 .......................................................... 502700 .......................................................... 152701 .............................................. 72, 73, 742703 .......................................................... 722704 .......................................................... 722709 .......................................................... 722725 .............................................. 72, 73, 742727 .................................................... 72, 75

3000

3000 .......................................................... 153001 ........................................ 56, 57, 58, 593002 .............................................. 57, 58, 593003 .......................................................... 59

4000

4100 .................................................... 16, 844101 ............................16, 43, 44, 89, 90, 924121 .................................................... 16, 174141 .................................................... 16, 174161 .................................................... 17, 444181 .................................................... 17, 844800 ........................................ 17, 18, 44, 914801 .............................................. 18, 44, 844900 ........................................ 20, 89, 90, 934901 .............................................. 20, 90, 93

5000

5700 .............................................. 19, 89, 925701 .......................................................... 195702 .......................................................... 195703 .......................................................... 195704 .......................................................... 195705 .......................................................... 19

7UT51 v3

98 PRCM-1108A-0199

Address Index (Continued)5706 .......................................................... 19 5707 .......................................................... 195708 .......................................................... 195709 .......................................................... 195710 .......................................................... 195711 .......................................................... 195721 .......................................................... 195722 .......................................................... 195723 .......................................................... 195724 .......................................................... 195725 .......................................................... 195726 .......................................................... 195727 .......................................................... 195728 .......................................................... 195729 .......................................................... 195730 .......................................................... 195731 .......................................................... 195900 .............................................. 19, 89, 925911 .......................................................... 195912 .......................................................... 195913 .......................................................... 195914 .......................................................... 195921 ............................ 19, 23, 72, 73, 74, 755922 .......................................................... 195923 .......................................................... 195924 .......................................................... 19

6000

6201 .......................................................... 236202 .......................................................... 236203 .......................................................... 236206 .......................................................... 236207 .......................................................... 236208 .......................................................... 236209 .......................................................... 236210 .......................................................... 236211 .......................................................... 236300 .................................................... 14, 946301 .......................................................... 236302 .......................................................... 236303 .......................................................... 236304 .......................................................... 23

6307 .......................................................... 236308 .......................................................... 236309 .......................................................... 236310 .......................................................... 236311 .......................................................... 236312 .......................................................... 236401 .......................................................... 236405 .......................................................... 23

7000

7100 .................................................... 14, 167105 .............................................. 16, 91, 947106 .............................................. 16, 91, 947107 .............................................. 16, 23, 947108 .............................................. 16, 23, 947110 .......................................................... 167200 .......................................................... 147221 .......................................................... 937222 .......................................................... 937400 .......................................................... 207402 .................................................... 20, 897411 .......................................................... 207431 .......................................................... 207432 .......................................................... 207800 .............................................. 35, 91, 937806 ......................17, 42, 76, 77, 78, 79, 837807 ......................17, 42, 76, 77, 78, 79, 837816 .......................................................... 247819 ..................................14, 76, 77, 78, 797821 .................................................... 15, 607824 .................................................... 15, 507825 .................................................... 15, 507827 ........................................ 15, 72, 73, 757830 .................................................... 15, 567831 .................................................... 15, 56

8000

8300 .......................................................... 938301 .......................................................... 93

Siemens Power Transmission & Distribution, LLCDistribution Automation DivisionP.O. Box 29503Raleigh, NC 27626-0503

Manual No. PRCM-1108A-0199Printed in U.S.A. Subject to change without notice.

© 1999 Siemens Power Transmission & Distribution, LLCSiemens is a registered trademark of Siemens AG.

Documents

7ut51_v3 Acceptance Testing Commissioning and Maintenance Manual