dated November, 1995 REL-300 (MDAR) Relaying System Version 2 · REL-300 (MDAR) Relaying System Version 2.62 40-385.5 ABB Network Partner. Go to Table of Contents to easily access

ABB Automation, Inc.Substation Automation & Protection DivisionCoral Springs, FLAllentown, PA

Instruction Leaflet

Effective: January, 1996Supersedes IL 40-385.5dated November, 1995

Numerical Distance ProtectionREL-300 (MDAR) RelayingSystem Version 2.62

40-385.5

ABB Network Partner

ABB Note

Go to Table of Contents to easily access each individual section. Click on the ABB logo to return to the Section TOC page.

MDAR REVISION NOTICE

CHANGE SUMMARY:

A CHANGE BAR ( ) LOCATED IN THE MARGIN REPRESENTS ATECHNICAL CHANGE TO THE PRODUCT.

A STAR (*) LOCATED BY THE SUB NUMBER REPRESENTS ATECHNICAL CHANGE TO THE DRAWING.

DATE REV. LEVEL PAGES REMOVED PAGES INSERTED

11/95 Released

I.L. 40-385.6

Significant Changes to Version 2.62 (From V2.60)

1. Corrected the display for 1-a ct style. Now, the angles of currents will be blocked only if the magnitudesof currents are below 10% of ct rating.

2. Used JMP-3 to perform the following functions.a) If JMP-3 = OUT, the 150 ms timer for LOPB maintains the same as V2.60, e.g., the LOPB will not blockthe distance units if a fault is detected within 150 ms after LOP = 1.

b) If JMP-3 = IN, change the timer of 150 ms to 500 ms for the LOP condition.

3. Removed LOPB and LOI from AL-1 relay and removed GS function. Use GS relay for LOPB or LOIBalarm (AL-3).

4. Corrected and removed KI0 from 3-phase fault formula for the distance protection and display.

5. Added ITP/ITG to the Reclose logic. For V2.60 and 3ZNP application, MDAR may not give 3-pole reclos-ing due to ITP/ITG trip if the zone-1 setting is “OUT”.

6. Removed AND144C and OR144D. Used pre-fault voltages (FDOPA & FDOPB & FDOPC) to superviseAND130 and AND176 for zone-1 and pilot high speed 3-phase fault trip, e.g., the pre-fault voltage super-vision is always in regardless of the setting of OSB.

7. Used TRSLA/TRSLB/TRSLC (OR54) to replace TRSL/HST at AND49A, AND49E and AND24 due to theneed of single pole application.

8. Added AND144E between OR145 and OR144B for zone-1 and single pole trip. The AND144E has twoinputs - OR145 and X2. The relay should trip on the second fault after the SPT regardless of the phasetype selection.

9. Added an OR76A between AND48A and AND76. Added WFT3 to the input of OR76A. In V2.60, there areno trip actions for multi-phase fault (Ph-Ph or 3-Ph) with the settings of TTYP=SR3R, STYP=POTT andWFEN=YES.

10. Changed the SPF logic by removing the gates of OR77E, OR77F, OR77G, AND77A, OR77D. Addedgates AND48G and OR48H and a timer (2/0) between X2 and AND77. Version 2.60 did not show SPFconsistently and might not give RB signal.

11. Added OR72A, OR73A, OR74A for single-pole phase-to-ground fault detection and AND48E, OR48F forphase fault detection. This is for security purpose especially an evolving fault and/or high-set (ITG) tripinvolved.

12. TRSL (NOT) was added to the inputs of AND69, 70, 71 to prevent the SRI due to the pole-span alignmentduring the three-pole clearing.

13. Added XB (NOT) and XC (NOT) to AND72 for phase-A (similar changes for phase B, C on gates AND73,74) to prevent 2-pole trip condition.

14. LOIB timer was changed from 0.5/0.5 seconds to 10/0.5 seconds to insure the trip for zone-2 or zone-3faults for the long time delay settings of T2 and T3.

15. Corrected the software error to use the pre-fault voltage for the directional units (FDOG/RDOG) after sin-gle-pole trip.

NOTE: CONVERSION FROM MDAR FIRMWARE VERSION V2.60 TO V2.62 CAN BE ACCOMPLISHEDAS FOLLOWS:

i

I.L. 40-385.5

1. Standard precautions of static voltage discharges should be observed such as using agrounded wrist strap when handling Integrated Circuits.

2. Remove chips U103 and U104 from the Microprocessor module.

3. Replace chips U103 (G13) and U104 (G14) into the sockets.

4. Reprogram MDAR password through INCOM remote communication.

5. It is recommended to verify the relay’s operation per Section 2 of Appendix A2 (Acceptance/Maintenance Tests).

IMPORTANT APPLICATION NOTES

1. PILOT SYSTEM

a) The setting of Z3FR must be set to “REV” for system transient block and unequal pole external faultclearing.

b) The minimum setting of FDGT should be 3 cycles unless for some special application.

c) The carrier equipment for the use of the Blocking System should have a sending/self-receiving featurein order to block both ends for 3 cycles if a reverse fault is detected.

2. LOAD LOSS TRIP (LLT)For a system if its maximum tapped load may exceed minimum through-load in the protected line, thesetting of LLT should be set to “NO”. Refer to section 9.12 for the detailed information.

3. RECLOSE APPLICATIONThe signals from MDAR to Recloser are Reclose Initiate RI2 (3-pole), RI1 (Single-pole) and RecloseBlock (RB). The Reclose relay should have the following feature: if the Recloser receives RI and RB, theRB should have the preference and reset/lockout the reclose timer.

SINGLE-POLE TRIP APPLICATION

For a single-pole and high-speed trip application (TTYP=SRI/SR3R), the FDOG trip path for the high resis-

tance ground fault detection may not work for the phase-phase-ground fault condition because the phase

selector shows a fault type of phase-phase fault and it expects the Z1P or PLTP trip only. The purpose of

FDOG is for the detection of single phase with high resistance to ground fault only.

ii

I.L. 40-385.6

iii

It is recommended that the user of MDAR equipment become acquainted with the information in this instructionleaflet before energizing the system. Failure to do so may result in injury to personnel or damage to the equip-ment, and may affect the equipment warranty. If the MDAR relay system is mounted in a cabinet, the cabinetmust be bolted to the floor, or otherwise secured before MDAR installation, to prevent the system from tippingover.

All integrated circuits used on the modules are sensitive to and can be damaged by the discharge of static elec-tricity. Electrostatic discharge precautions should be observed when handling modules or individualcomponents.

ABB does not assume liability arising out of the application or use of any product or circuit described herein.ABB reserves the right to make changes to any products herein to improve reliability, function or design. Spec-ifications and information herein are subject to change without notice. All possible contingencies which mayarise during installation, operation, or maintenance, and all details and variations of this equipment do not pur-port to be covered by these instructions. If further information is desired by purchaser regarding a particular in-stallation, operation or maintenance of equipment, the local ABB representative should be contacted.

© CopyrightABB Power T&D Company Inc.Published 1993, 1994, 1995, 1996All Rights Reserved

ABB does not convey any license under its patent rights nor the rights of others.

! CAUTION

I.L. 40-385.5

iv

Table of ContentsPAGE NO.

Section 1 PRODUCT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Section 2 FUNCTIONAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Section 3 SYSTEM ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Section 4 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Section 5 DESCRIPTION OF SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Section 6 OPERATING PRINCIPLES OF SENSING UNITS. . . . . . . . . . . . . . . 6-1

Section 7 OPERATOR INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Section 8 SELF-CHECKING AND FUNCTIONAL TEST . . . . . . . . . . . . . . . . . . 8-1

Section 9 OPERATION OF BASIC FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . 9-1

Section 10 OPERATION OF PILOT AND OPTIONAL FUNCTIONS . . . . . . . . 10-1

Section 11 COMMUNICATION, FAULT DATA, INTERMEDIATE

TARGET AND OSCILLOGRAPHIC INFORMATION. . . . . . . . . . . . 11-1

Section 12 UNIQUE FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1

Section 13 SETTING CALCULATIONS AND SELECTIONS. . . . . . . . . . . . . . . 13-1

APPENDIX

A-1 FULL PERFORMANCE TESTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

A-2 ACCEPTANCE/MAINTENANCE TESTS. . . . . . . . . . . . . . . . . . . . .A-13

A-3 SYSTEM DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-24

Trademarks

All terms mentioned in this book that are known to be trademarks or service marks are listed below. In addition,terms suspected of being trademrks or service marks have been appropriately capitalized. ABB Power T&D Com-pany Inc. cannot attest to the accuracy of this information. Use of a term in this book should not be regarded asaffecting the validity of any trademark or service mark.

IBM and PC are registered trademarks of the International Business Machines Corporation.WRELCOM is the registered trademark of the ABB Power T&D Company Inc.INCOM is the registered trademark of the Westinghouse Electric Corporation

ABB Note

Click on the Section Title to access the desired section. To return to TOC, Click on the ABB logo on the first page of each section.

I.L. 40-385.6

v

List of Figures

FIGURE NO.PAGE

1 MDAR (REL-300) Relay Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . A-24

2 Layout of MDAR Modules within Inner and Outer Chassis . . . . . . . . . . . . . . . A-24


4 MDAR (REL-300) Module Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-25


6 MDAR (REL-300) Relay Backplane Board Terminals . . . . . . . . . . . . . . . . . . A-27

7 Overall Flowchart for Microprocessor Software in MDAR (300) Relay . . . . . . . . . A-28

8 Mho Characteristic for ØØ/ØØG Faults (no load flow). . . . . . . . . . . . . . . . . . A-29

9 Mho Characteristic for ABC Faults (no load flow) . . . . . . . . . . . . . . . . . . . . A-29

10 Mho Characteristic for ØG Faults (no load flow) . . . . . . . . . . . . . . . . . . . . . A-30

11 Double Blinder Characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-30

12 Loss-of-Potential Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-31

13 AC Current Monitoring Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-32


15 MDAR (REL-300) Zone-1 Trip Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . A-33



18 MDAR (REL-300) Highset Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . A-36

19 MDAR (REL-300) Close-into-Fault Trip . . . . . . . . . . . . . . . . . . . . . . . . . A-36

20 MDAR (REL-300) Unequal-Pole Closing Load Pickup Control . . . . . . . . . . . . . A-37

21 MDAR (REL-300) Inverse Time Overcurrent Ground Backup Logic. . . . . . . . . . . A-37

22 MDAR (REL-300) Zone-1 Extension Scheme . . . . . . . . . . . . . . . . . . . . . . A-38

23 Load-Loss Acellerated Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-37

24 Reclosing Initiation Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-39

25 Load-Loss Accelerated Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-40

26 Pilot Trip Relay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-41

27 POTT/Unblocking, Pilot Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-41

28 Carrier Keying/Receiving Logic in POTT/Unblocking Schemes . . . . . . . . . . . . . A-42

29 PUTT Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-43

30 Blocking System Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-44

31 (Blank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-44

32 (Blank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-45

33 Weakfeed Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-45

34 FDOG Supplements PLTG for High Rg Faults . . . . . . . . . . . . . . . . . . . . . A-46

35 Power Reversal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-46

36 Reverse-Block Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-47

37 Unequal-Pole Closing on Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-48

I.L. 40-385.5

vi

38 Simplified MDAR Version 2.60 SPT Logic . . . . . . . . . . . . . . . . . . . . . . . . A-49

39 MDAR Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-50

40 System Drawing (V2.60) pg 1 of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-51

41 System Drawing (V2.60) pg 2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . A-52


List of Figures (continued)

NUMERICAL DISTANCE PROTECTION MDAR (REL-300) RELAYING SYSTEMS

ABB Power T&D Company Inc.Relay Division

Coral Springs, FL 33065

4300 Coral Ridge Drive

January 1996

Instruction Manual

40-385.5

V2.62

(954) 752-6700 (800) 523-2620

MDAR REVISION NOTICE

CHANGE SUMMARY:

A CHANGE BAR ( ) LOCATED IN THE MARGIN REPRESENTS ATECHNICAL CHANGE TO THE PRODUCT.

A STAR (*) LOCATED BY THE SUB NUMBER REPRESENTS ATECHNICAL CHANGE TO THE DRAWING.

DATE REV. LEVEL PAGES REMOVED PAGES INSERTED

11/95 Released

I.L. 40-385.6

i

Significant Changes to Version 2.62 (From V2.60)

1. Corrected the display for 1-a ct style. Now, the angles of currents will be blocked only if the magnitudesof currents are below 10% of ct rating.

2. Used JMP-3 to perform the following functions.a) If JMP-3 = OUT, the 150 ms timer for LOPB maintains the same as V2.60, e.g., the LOPB will not blockthe distance units if a fault is detected within 150 ms after LOP = 1.

b) If JMP-3 = IN, change the timer of 150 ms to 500 ms for the LOP condition.

3. Removed LOPB and LOI from AL-1 relay and removed GS function. Use GS relay for LOPB or LOIBalarm (AL-3).

4. Corrected and removed KI0 from 3-phase fault formula for the distance protection and display.

5. Added ITP/ITG to the Reclose logic. For V2.60 and 3ZNP application, MDAR may not give 3-pole reclos-ing due to ITP/ITG trip if the zone-1 setting is “OUT”.

6. Removed AND144C and OR144D. Used pre-fault voltages (FDOPA & FDOPB & FDOPC) to superviseAND130 and AND176 for zone-1 and pilot high speed 3-phase fault trip, e.g., the pre-fault voltage super-vision is always in regardless of the setting of OSB.

7. Used TRSLA/TRSLB/TRSLC (OR54) to replace TRSL/HST at AND49A, AND49E and AND24 due to theneed of single pole application.

8. Added AND144E between OR145 and OR144B for zone-1 and single pole trip. The AND144E has twoinputs - OR145 and X2. The relay should trip on the second fault after the SPT regardless of the phasetype selection.

9. Added an OR76A between AND48A and AND76. Added WFT3 to the input of OR76A. In V2.60, there areno trip actions for multi-phase fault (Ph-Ph or 3-Ph) with the settings of TTYP=SR3R, STYP=POTT andWFEN=YES.

10. Changed the SPF logic by removing the gates of OR77E, OR77F, OR77G, AND77A, OR77D. Addedgates AND48G and OR48H and a timer (2/0) between X2 and AND77. Version 2.60 did not show SPFconsistently and might not give RB signal.

11. Added OR72A, OR73A, OR74A for single-pole phase-to-ground fault detection and AND48E, OR48F forphase fault detection. This is for security purpose especially an evolving fault and/or high-set (ITG) tripinvolved.

12. TRSL (NOT) was added to the inputs of AND69, 70, 71 to prevent the SRI due to the pole-span alignmentduring the three-pole clearing.

13. Added XB (NOT) and XC (NOT) to AND72 for phase-A (similar changes for phase B, C on gates AND73,74) to prevent 2-pole trip condition.

14. LOIB timer was changed from 0.5/0.5 seconds to 10/0.5 seconds to insure the trip for zone-2 or zone-3faults for the long time delay settings of T2 and T3.

15. Corrected the software error to use the pre-fault voltage for the directional units (FDOG/RDOG) after sin-gle-pole trip.

NOTE: CONVERSION FROM MDAR FIRMWARE VERSION V2.60 TO V2.62 CAN BE ACCOMPLISHEDAS FOLLOWS:

I.L. 40-385.5

ii

1. Standard precautions of static voltage discharges should be observed such as using agrounded wrist strap when handling Integrated Circuits.

2. Remove chips U103 and U104 from the Microprocessor module.

3. Replace chips U103 (G13) and U104 (G14) into the sockets.

4. Reprogram MDAR password through INCOM remote communication.

5. It is recommended to verify the relay’s operation per Section 2 of Appendix A2 (Acceptance/Maintenance Tests).

IMPORTANT APPLICATION NOTES

1. PILOT SYSTEM

a) The setting of Z3FR must be set to “REV” for system transient block and unequal pole external faultclearing.

b) The minimum setting of FDGT should be 3 cycles unless for some special application.

c) The carrier equipment for the use of the Blocking System should have a sending/self-receiving featurein order to block both ends for 3 cycles if a reverse fault is detected.

2. LOAD LOSS TRIP (LLT)For a system if its maximum tapped load may exceed minimum through-load in the protected line, thesetting of LLT should be set to “NO”. Refer to section 9.12 for the detailed information.

3. RECLOSE APPLICATIONThe signals from MDAR to Recloser are Reclose Initiate RI2 (3-pole), RI1 (Single-pole) and RecloseBlock (RB). The Reclose relay should have the following feature: if the Recloser receives RI and RB, theRB should have the preference and reset/lockout the reclose timer.

SINGLE-POLE TRIP APPLICATION

For a single-pole and high-speed trip application (TTYP=SRI/SR3R), the FDOG trip path for the high resis-

tance ground fault detection may not work for the phase-phase-ground fault condition because the phase

selector shows a fault type of phase-phase fault and it expects the Z1P or PLTP trip only. The purpose of

FDOG is for the detection of single phase with high resistance to ground fault only.

I.L. 40-385.6

iii

It is recommended that the user of MDAR equipment become acquainted with the information in this instructionleaflet before energizing the system. Failure to do so may result in injury to personnel or damage to the equip-ment, and may affect the equipment warranty. If the MDAR relay system is mounted in a cabinet, the cabinetmust be bolted to the floor, or otherwise secured before MDAR installation, to prevent the system from tippingover.

All integrated circuits used on the modules are sensitive to and can be damaged by the discharge of static elec-tricity. Electrostatic discharge precautions should be observed when handling modules or individualcomponents.

ABB does not assume liability arising out of the application or use of any product or circuit described herein.ABB reserves the right to make changes to any products herein to improve reliability, function or design. Spec-ifications and information herein are subject to change without notice. All possible contingencies which mayarise during installation, operation, or maintenance, and all details and variations of this equipment do not pur-port to be covered by these instructions. If further information is desired by purchaser regarding a particular in-stallation, operation or maintenance of equipment, the local ABB representative should be contacted.

© CopyrightABB Power T&D Company Inc.Published 1993, 1994, 1995, 1996All Rights Reserved

ABB does not convey any license under its patent rights nor the rights of others.

! CAUTION

I.L. 40-385.5

iv

Table of ContentsPAGE NO.

Section 1 PRODUCT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Section 2 FUNCTIONAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Section 3 SYSTEM ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Section 4 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Section 5 DESCRIPTION OF SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Section 6 OPERATING PRINCIPLES OF SENSING UNITS. . . . . . . . . . . . . . . 6-1

Section 7 OPERATOR INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Section 8 SELF-CHECKING AND FUNCTIONAL TEST . . . . . . . . . . . . . . . . . . 8-1

Section 9 OPERATION OF BASIC FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . 9-1

Section 10 OPERATION OF PILOT AND OPTIONAL FUNCTIONS . . . . . . . . 10-1

Section 11 COMMUNICATION, FAULT DATA, INTERMEDIATE

TARGET AND OSCILLOGRAPHIC INFORMATION. . . . . . . . . . . . 11-1

Section 12 UNIQUE FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1

Section 13 SETTING CALCULATIONS AND SELECTIONS. . . . . . . . . . . . . . . 13-1

APPENDIX

A-1 FULL PERFORMANCE TESTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

A-2 ACCEPTANCE/MAINTENANCE TESTS. . . . . . . . . . . . . . . . . . . . .A-13

A-3 SYSTEM DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-24

Trademarks

All terms mentioned in this book that are known to be trademarks or service marks are listed below. In addition,terms suspected of being trademrks or service marks have been appropriately capitalized. ABB Power T&D Com-pany Inc. cannot attest to the accuracy of this information. Use of a term in this book should not be regarded asaffecting the validity of any trademark or service mark.

IBM and PC are registered trademarks of the International Business Machines Corporation.WRELCOM is the registered trademark of the ABB Power T&D Company Inc.INCOM is the registered trademark of the Westinghouse Electric Corporation

ABB Note

Click on the Section Title to access the desired section.

I.L. 40-385.6

v

List of Figures

FIGURE NO.PAGE


2 Layout of MDAR Modules within Inner and Outer Chassis . . . . . . . . . . . . . . . A-24


4 MDAR (REL-300) Module Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-25


6 MDAR (REL-300) Relay Backplane Board Terminals . . . . . . . . . . . . . . . . . . A-27

7 Overall Flowchart for Microprocessor Software in MDAR (300) Relay . . . . . . . . . A-28

8 Mho Characteristic for ØØ/ØØG Faults (no load flow). . . . . . . . . . . . . . . . . . A-29

9 Mho Characteristic for ABC Faults (no load flow) . . . . . . . . . . . . . . . . . . . . A-29

10 Mho Characteristic for ØG Faults (no load flow) . . . . . . . . . . . . . . . . . . . . . A-30


12 Loss-of-Potential Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-31

13 AC Current Monitoring Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-32





18 MDAR (REL-300) Highset Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . A-36

19 MDAR (REL-300) Close-into-Fault Trip . . . . . . . . . . . . . . . . . . . . . . . . . A-36

20 MDAR (REL-300) Unequal-Pole Closing Load Pickup Control . . . . . . . . . . . . . A-37

21 MDAR (REL-300) Inverse Time Overcurrent Ground Backup Logic. . . . . . . . . . . A-37

22 MDAR (REL-300) Zone-1 Extension Scheme . . . . . . . . . . . . . . . . . . . . . . A-38

23 Load-Loss Acellerated Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-37

24 Reclosing Initiation Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-39

25 Load-Loss Accelerated Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-40

26 Pilot Trip Relay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-41

27 POTT/Unblocking, Pilot Trip Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-41

28 Carrier Keying/Receiving Logic in POTT/Unblocking Schemes . . . . . . . . . . . . . A-42

29 PUTT Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-43

30 Blocking System Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-44

31 (Blank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-44

32 (Blank) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-45

33 Weakfeed Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-45

34 FDOG Supplements PLTG for High Rg Faults . . . . . . . . . . . . . . . . . . . . . A-46

35 Power Reversal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-46

36 Reverse-Block Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-47

37 Unequal-Pole Closing on Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-48

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38 Simplified MDAR Version 2.60 SPT Logic . . . . . . . . . . . . . . . . . . . . . . . . A-49

39 MDAR Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-50


41 System Drawing (V2.60) pg 2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . A-52


List of Figures (continued)

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1.1 IINTRODUCTION

MDAR (REL-300) version 2.60 is a special design forChina. It meets the general operation practices inChina.

MDAR (REL-300) version 2.60 is a microcontroller-based line protection system. All measurement, pro-tection and logic functions are performed by numeri-cal/digital means. The basic relay provides threezones of distance protection with instantaneousdirectional high set trip and directional inverse timeovercurrent ground backup functions. MDAR (REL-300) version 2.60 also has metering, fault location,oscillographic and communication capabilities.

The capabilities of the basic MDAR (REL-300) ver-sion 2.60 can be expanded to include any one or allof the optional functions, such as out-of-step block,pilot zone and single-pole trip. It may be used fortransmission line protection at any voltage level.

1.2 MAJOR DIFFERENCES BETWEENVERSIONS 2.60 AND 2.10

The hardware of the MDAR (REL-300) version 2.60is the same as the standard MDAR (REL-300) ver-sion 2.10, except the software is modified in the fol-lowing areas:

1.2.1 Out-of-step logic.

(a) OSB function is selectable. The selected OSBblocks Z1/Z2 /pilot 3Ø-unit only. (note, it doesnot supervise Z3).

(b) The logic of using double blinder with OS timerfor OS detection is similar to the OS logic in thestandard MDAR (REL-300) version 2.10,except the OS timer is changed from 50/0 to50/(500, 1000) ms (i.e., setable reset timer).

(c) For Z1 and pilot OSB, besides the normal logicof [(21BO and not 21BI) and (OS timer)] forsupervision, an 200/(500, 1000) ms timer andlogic are added to the circuit for blocking whenthe 21BI is operated for longer than 200 ms.

(d) Separated out-of-step override timers, OSOT1and OSOT2, for Z1 and Z2. Timer range is(500, 1000/0) ms in stead of 400-4000/0 ms.

1.2.2 Single pole trip logic.

(a) Use trip signals TRSLA, TRSLB, TRSLC andthe resetting of faulted phase current signal forpole-disagreement identification.

(b) The SPF, ROF and 62T logic for SPT havebeen modified.

1.2.3 Due to the hardware limitation, the Stub busand 3-terminal protection function are not available inversion 2.60.

1.2.4 Load restriction for long line application is notincluded in version 2.60 based on the specification(refer to EPRI’s Figure 1, dated 6/92).

1.2.5 Optional programmable output contactarrangement is not available in version 2.60.

1.2.6 External wirings are different from the ver-sion 2.10.

1.3 MDAR (REL-300) DESIGN CONCEPTS

The MDAR (REL-300) design concept is to provide adesign that combines ABB's relay design, manufac-turing and application experience with new technol-ogy to insure a product that will meet the needs of abroad range of electric utility operations to satisfytoday's requirements and provide direction for tomor-row's solutions, with hardware design simplicity andincreased software functionality.

1.3.1 The MDAR (REL-300) is designed for theprotection engineer

It enables the engineer to easily apply the appropri-ate functional capabilities of MDAR (REL-300) tomeet a specific applications requirement.

Fault data and oscillographic information are alsoavailable through remote communications to aid theengineer to more effectively analyze system faultsand relay operations for future system design consid-eration.

1.3.2 The MDAR (REL-300) is designed for systemoperations

It provides operations the means to quickly accessfault location data, thereby minimizing transmissionline outage times.

Section 1. PRODUCT DESCRIPTION

I.L. 40-385.5

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Also, MDAR (REL-300)'s continuous self checkingdiagnostics and failure alarm forewarns operations ofproblem areas, permitting prompt corrective actions.

1.3.3 The MDAR (REL-300) is designed for themaintenance department

MDAR (REL-300)'s compact drawout design with afront panel operator's interface and test switches pro-vides for easier installation and testing. The hard-ware design simplicity utilizing minimum componentsof proven reliability, self checking diagnostics andfailure alarm make the MDAR (REL-300) virtuallymaintenance free. All of these contribute to savingmaintenance program time, effort, travel and cost tokeep relays in the proper operating condition.

1.3.4 The MDAR (REL-300) is designed for utilitymanagement

It provides management the means to effectivelyaddress cost reduction and customer service goalsthrough assuring the implementation of MDAR (REL-300) and related technologies to their full advantage.

1.4 BENEFITS

There is no question of the potential benefits themicroprocessor can bring to the system protectionfunction, as well as the overall operation of the elec-tric utility. The implementation of these technologieswill be paced as we gradually grow into the future,changing and improving our concepts of operatingrequirements.

And we have with MDAR (REL-300), a productdesigned for today's requirements and tomorrow'ssolutions, simply and logically.

1.5 REFERENCES:

Catalog number presently available at this applica-tion are: (the last digit “C” represents the “China soft-ware” version 2.60 as described for step Amodifications)

MD-3A2SPFRC 3-pole trip, 1 amp ct, 250 Vdc,with OSB, Pilot system, FT-switch and RS-232 communica-tion device.

MD-1B2SPFCC Single-pole trip, 5 amp ct, 250Vdc, with OSB, Pilot system, FT-switch and INCOM communica-tion device.

MD-3B2SPFCC 3-pole trip, 5 amp ct, 250 Vdc,with OSB, Pilot system, FT-switch and INCOM communica-tion device.

MD-3A2SPFCC 3-pole trip, 1 amp ct, 250 Vdc,with OSB, Pilot system, FT-switch and INCOM communica-tion device.

MD-1B2SPFRC Single-pole trip, 5 amp ct, 250Vdc, with OSB, Pilot system, FT-switch and RS-232 communica-tion device.

System drawing for this application is 2690F96.

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2.1 STANDARD FUNCTIONS FOR PILOT MDAR(REL-300) VERSION 2.60

2.1.1 3 Step Distance Phase And Ground WithIndependent Pilot Phase And Ground Zones(Each Zone Has 4 Impedance Units)

(a) Z1P/Z1G (zone-1 with selectable 0 to 15cycles, in 1.0 cycle steps T1 timer),

(b) Z2P/Z2G (zone-2 with separated phase andground timers, each timer can be disabledindependently),

(c) Z3P/Z3G (zone-3, reversible directional withseparated phase and ground timers, each timercan be disabled independently).

(d) PLTP/PLTG (pilot zone).

2.1.2 Selectable instantaneous forward directionalovercurrent function for high Rf ground faultsupplement to overreach pilot, with adjust-able 0-15 cycle timer in 1 cycle steps.

2.1.3 Selectable inverse time directional or non-directional overcurrent ground backup (GB,with similar CO-2, CO-5, CO-6, CO-7, CO-8,CO-9 AND CO-11 characteristics).

2.1.4 Directional high-set instantaneous direct tripincluding 3 phase and one ground overcur-rent units (ITP/ITG) for SPT/3PT applica-tions.

2.1.5 Instantaneous reverse directional overcurrentground function for carrier ground start onblocking scheme.

2.1.6 Scheme selection:

(a) Non-pilot 3-Zone distance.

(b) Zone-1 extension.

(c) Blocking.

(d) PUTT (permissive underreach transfer trip).

(e) POTT (permissive overreach transfer trip) andUnblocking.

2.1.7 Additional/Unique functions:

(a) Current and voltage change fault detectors (∆I,∆V).

(b) Overcurrent supervision of phase and grounddistance units.

(c) Loss-of-potential supervision (LOPB).

(d) Loss-of-current monitoring (LOI).

(e) Close-into-fault trip (CIFT) with LV-unit supervi-sion.

(f) (Unequal-pole-closing load pickup trip logic.

(g) Selectable loss-of-load accelerated trip logic(LLT).

(h) Transient block logic for power reversal (TBM).

(i) Weakfeed trip application.

(j) Reclose block on breaker failure squelch.

(k) Selectable Dual or Zero sequence voltagepolarizing, or Negative sequence quantitiesoperated directional element for ground unitsupervision.

(l) Programmable reclosing initiation (RI) andreclosing block outputs (RB); Reclose initiatecan be enabled with the selection of:

1PR — reclose on ØG faults2PR — reclose on ØG/ØØ/ØØG faults3PR — reclose on ØG/ØØ/ØØG/3Ø faults

(m) Continuous self-check function.

(n) Fault locator function.

(o) 16 fault records storage with selectable capturemode.

(p) 16 sets of oscillographic data with selectableOSC data capture mode.

(q) Line voltage, current and phase angle monitor.

(r) Real time clock.

(s) Breaker trip circuit test.

(t) Push-to-close test for output contacts.

(u) Software switches for functional tests (e.g. TKand RS1).

Section 2. FUNCTIONAL SPECIFICATION

I.L. 40-385.5

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(v) Trip contact sealed in by trip current; andselectable dropout delay timer (0/50 ms.).

(w) Selectable trip alarm seal-in.

(x) RS-232C/PONI or INCOM/PONI data commu-nication attachments.

(y) Out-of-step block function with special designlogic for China.

2.2 OPTIONAL FUNCTIONS

2.2.1 Optional FT-14 switches.

2.2.2 Optional Single-pole-trip function with specialdesign logic for China. This function includesthe following functions:

(a) SPT/SRI on first fault.

(b) 3PT/RB if reclosing on a permanent fault.

(c) 3PT/RB if second phase(s) fault during single-phasing.

(d) 3PT on a preset time limit (62T) if the systemfails to reclose.

(e) Trip/RI mode selection.

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3.1 THE COMPLETE MDAR (REL-300) LINEPROTECTION SYSTEM

The complete MDAR (REL-300) Line Protection Sys-tem is housed in a 19-inch rack-mount package, 4rack units (7 inches, 177.8 mm.) high, 19.0 inches(482.6 mm.) width, 14.0 inches (356 mm.) depth,weight 35 lbs. (16 kgs), as shown in Figure 1. It con-sists of 6 basic and one optional modules. The 6basic modules are backplane module, interconnectmodule, power supply module, filter module, micro-processor module and operator interface module. AnINCOM communication network interface or RS-232C port provides remote data communication. Thetwo optional FT-14 switches are also available, asshown in Figure 2.

For single-pole tripping applications, an optional sin-gle-pole trip module is added with the extra relays fortripping and BFI functions.

All user connections, including the serial data port forcommunication, are on the rear panel. The frontpanel presents controls and displays for the operator;on either side are the (optional) type FT-14 testswitches. The test switches permit convenient andsafe disconnection of trip and ac input circuits, andmake it easy for the user to inject test signals.

An overall block diagram and the display panel ofMDAR (REL-300) relay are as shown in Figures 3and 4, respectively.

3.2 BACKPLANE MODULE

The analog input circuitry consists of seven trans-formers. Four currents (IA, IB, IC, and IP) and threevoltages (VA, VB and VC). The Ip input is used forzero-sequence dual-polarizing ground current mea-surement; the input is from the power transformerneutral ct (Figure 5). The seven isolation transform-ers are mounted on the transformer board which isattached to the backplane module (Figure 2). Theydrive resistive burdens to develop a secondary volt-age which will be proportional to the primary input.The current transformers are non-gapped. DC offsetattenuation is done with a digital filtering algorithm.

The first-line surge protection for each input and out-put terminals are also located on the backplane mod-

ule. The backplane module is mounted on the outerchassis. All of the relay circuitry is located on theother modules, mounted on the inner chassis, towhich the front panel is attached. The inner chassisslides in or out of the outer chassis from the front.

The backplane module receives all external connec-tions (with or without the FT-14 switch option), andconnects directly to the interconnect module, thruplug-in connectors which provide the connectionbetween outer and inner chassis. Mating connectorsinside the case eliminate the need to disconnectexternal wiring when the inner chassis is removed.

The INCOM or RS-232C PONI is mounted on theBackplate of the outer chassis and is connected tothe Backplane module.

3.3 INTERCONNECT MODULE

The interconnect module becomes the floor of theMDAR (REL-300) inner chassis: it provides electricalconnections from the backplane module to the othermodules. Two dc power fuses, two alarm relays (fail-ure alarm AL1 and trip alarm AL2), and seven opticalisolation circuits are included on the interconnectmodule in addition to the signal routing and connec-tors to the other modules. The failure alarm relay AL1is normally picked up, but the processor will deener-gize it when a problem is found. The trip alarm relayAL2 will be sealed-in if the AL2S is set to YES. Sta-tus input information is interfaced to the microproces-sor via seven optical isolators. They are:

• the status inputs from the breaker auxiliary con-tact “52b”,

• the pilot channel receiver output “RX1”,

• the external “pilot enable” switch, (it is equiva-lent to the 85CO device in a conventional pilotsystem),

• the external target reset switch,

• the three status inputs, XTRIPA, XTRIPB andXTRIPC, from the external trip circuits for SPTapplication.

Terminals for these signal connections are located onthe rear panel of the outer chassis (Figure 6). Theinput voltage level of these optical isolators can be

Section 3. SYSTEM ASSEMBLY

I.L. 40-385.5

3-2

selected by setting the jumpers, JMP1 thru JMP6and JMP13, on the interconnect module. JMP7 andJMP9 should always be selected for XTRIPB applica-tion.

The trip alarm will be sealed-in, until externally reset(local or remote), if the AL2S (alarm-2 seal-in) isselected to YES. The relay failure alarm (alarm-1) willself reset once the abnormal condition has beenremoved.

3.4 POWER SUPPLY MODULE

The power supply module provided isolation from thestation battery and includes overcurrent and overvolt-age protection. Status monitoring (self-check) isaccomplished via a failure alarm relay (AL-1). the fail-ure alarm relay is normally pickedup, but the proces-sor de-energize it when a problem is found. Loss ofpotential (LOP) and loss of current (LOI) are indi-cated by a GS reed relay (AL-3) which is normallyde-energized. The GS relay will be picked up for atotal ac power loss. Front panel test points areincluded for all power supply voltages. The powersupply module is available in three ranges:

38-70 Vdc 88-145 Vdc 176-290 Vdc.

Twelve output relays are also located on the powersupply module. Their functions are:

Contacts from K1 thru K7, K10 and K14 are wired outfor external uses. All trip, BFI, RI1, RI2 and RB con-tacts are provided for two breaker applications (Fig-ure 6). The trip output contacts will have a 50 ms.

Relay Function Type Contacts Rating

K1 Trip A Telephone SPDT 10 A

K2 Trip A Telephone SPDT 10 A

K3 Breaker failure initiate Telephone DPDT 5 A

K4 Carrier stop (STOP) Reed *1A or 1B 24 V

K5 SRI (RI1) Telephone DPDT 5 A

K6 3RI (RI2) Telephone DPDT 5 A

K7 RB Telephone DPDT 5 A

K8 K1 Breaker current monitor Reed Form A 0.5 A


K10 Carrier send (SEND) Reed *1A or 1B 24 V

K13 System test Telephone DPDT 5 A

K14 Alarm-3 (GS for LOP & LOI) Reed 1A 24 V

* See Section 4 paragraph 4.2 (4) for more information

delay on dropout if jumper JMP4 on the processormodule is on. The General Start contact (GB) is pro-vided for starting the external recorder.

Contacts from K8, K9 and K13 provide inputs to themicroprocessor module. Reed relays K8 and K9 arebuilt-in the trip circuits for sensing the trip coil currentflow and seal-in the trip output relay if the trip coil cur-rent is higher than 0.5 amps.

The System Test relay K13 is normally energizedthrough an external jumper, terminals 13 and 14 on2FT-14, connected to the DC supply voltage (Figure5). During system testing K13 is de-energized byopening an FT switch which disables the reclose ini-tiate relays, K5 and K6. The above mentioned exter-nal jumper also direct control the power supply forthe BFI relay K3.

3.5 FILTER MODULE

The filter module contains the anti-aliasing filters forthe analog inputs, IA, IB, IC, IP, VAG, VBG and VCG.The analog inputs are supplied from the isolationtransformers via the backplane and the interconnectmodules. The filter analog signal outputs are sup-plied to the microprocessor module. The active low-pass filters are third-order Butterworth filters with acutoff frequency of 240 Hz. This meets the Nyquist

criterion for the MDAR (REL-300) sampling rate of 8samples per cycle (480 Hz at 60 Hz and 400 Hz at 50Hz).

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3.6 MICROPROCESSOR MODULE

The MDAR (REL-300) microprocessor module con-trols the MDAR (REL-300) system. It contains theA/D conversion circuitry, the I/O circuitry and thefollowing components:

One microcontroller (U100) — The Intel 80C196KBmicrocontroller is a 16-bit CMOS processor operatesat 10 MHz frequency with two 16-bit timer/counters, ahigh-Speed I/O subsystem, 230 bytes of on-chipRAM, a watchdog timer, a serial port and numerousI/O lines.

EPROMs (U103 and U104) — Two separate, eas-ily-replaceable EPROM chips are for program mem-ory.

PAL (U105) — For programmable Array Logic.

RAMs (U200 AND U201) — Two volatile read-writememory chips are for working storage.

NOVRAM (U202) — One non-volatile RAM is for thestorage of settings, targets and data when the relayis deenergized.

A battery back-up real-time clock (U501) suppliestime and date information for time stamping targetdata. The real-time clock can be set through the frontpanel operator interface or using the RS-232C port orthe INCOM communication.

3.7 OPERATOR INTERFACE (OR DISPLAY)MODULE

An illustration of the display module appears in Fig-ure 4. It includes function and value display fields.Each is a 4-character, 14 segment, blue color vac-uum fluorescent, alphanumeric display, 0.7 inch high.A software display saver is built-in. The MDAR (REL-300) display will be on only 5 minutes after turning inthe DC power supply, or depressing any one of thefront panel pushbutton or detecting any fault on theline. LED's show display modes. Pushbuttonswitches, (no external equipment is required), areused to change modes, read target or operation data,call metering displays and enter settings.

A detailed description of the operator interface isincluded in Chapter VII.

3.8 OPTIONAL SINGLE-POLE TRIP MODULES

The optional module is required for single-pole trip-ping application. It plugs to the interconnect module,and is steadied by a center support bar.

The circuitry associated with the tripping of phases Band C is located on this module and is identical to thephase A trip circuit located on the power supply mod-ule. The functions of the ten relays on the optionalmodule are shown in chart below:

3.9 COMMUNICATION ATTACHMENTS(Refer To Chapter 11 For Detail)

Relay Function Type Contacts Rating

K1 Trip B Telephone SPDT 10 A

K2 Trip B Telephone SPDT 10 A



K5 Trip C Telephone SPDT 10 A

K6 Trip C Telephone SPDT 10 A





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4.1 EXTERNAL WIRINGS

As shown in Figure 5, the power system ac quantitiesVA, VB, VC, VN, IA, IB, IC and IP, as well as the dcsource are connected to the left side 1FT-14 switch(front view). All the trip contact outputs are connectedto the right side 2FT-14 switch (front view). Switches13 and 14 on the right side 2FT-14 may be used fordisabling the BFI/RI control logic when performingfunctional tests.

The INCOM or RS232 PONI communication box ismounted thru the backplate of the outer chassis andconnected to the Backplane module.

Dry contact outputs for breaker failure initiation (BFI),reclosing initiation (RI), reclosing block (RB), carriersend (SEND), carrier stop (STOP), failure alarm (AL-1) and trip alarm (AL-2) are located on the backplaneboard (Figure 6). Terminals for the seven optical iso-lators are used for RCVR1, Pilot Enable, ExternalReset, 52b, XTRIPA, XTRIPB and XTRIPC, andstuds for chassis ground (GND) are also on the back-plane board. The three external trip contactsXTRIPA, XTRIPB and XTRIPC are labeled on theMDAR (REL-300) relay as 52a, SBP and RCVR2,respectively.

application for version 2.60.

JMP8/JMP10, are not used for version 2.60.

JMP11 to JMP12 are factory set for MDAR(REL-300) style with FT-14.

(3) Jumpers on Processor Module

JMP1, JMP8 and JMP9 are for EEPROM andRAM circuits, normally factory set to position 1-2, unless specified.

JMP2 set at position 2-3 for MDAR (REL-300)system with single-pole trip,i.e., catalog num-ber MD1xxxxxxx.

Set at position 1-2 for MDAR (REL-300) systemwithout single-pole trip, i.e. catalog numberMD3xxxxxxx.

JMP3 set to OUT position for version 2.60.

JMP4 should normally be set to OUT. Set it toIN position for enabling the trip contact with 50ms dropout time delay feature.

JMP5 should normally be set to OUT. Set it toIN position for enabling the output contact testsfeature.

JMP6 should normally be set to OUT, exceptfor making A/D converter calibration.

JMP7 does not exist.

JMP10 to JMP12 are not used.

(4) Jumpers on Power Supply Module

JMP1 Carrier STOP function, position 1-2 forNO contact, and 2-3 for NC contact output.

JMP2 Carrier SEND function, position 1-2 forNO contact, and 2-3 for NC contact output.:

Positions for Power Supply Voltage

JMP1 XTRIPC 15/20, 48/125, 220/250 Vdc

JMP2 Pilot enable 15/20, 48/125, 220/250 Vdc

JMP3 Channel receiver 15/20, 48/125, 220/250 Vdc

JMP4 External reset 15/20, 48/125, 220/250 Vdc

JMP5 52b contact 15/20, 48/125, 220/250 Vdc

JMP6 XTRIPA 15/20, 48/125, 220/250 Vdc

JMP13 XTRIPB 15/20, 48/125, 220/250 Vdc

Section 4. INSTALLATION

4.2 JUMPERS

There are several jumpers on the interconnect andmicroprocessor modules for different functions.Proper jumper position should be set for differentapplications. The jumpers are:

(1) External Jumper

An external jumper is permanentlywired to terminals 2 and 4 of 2FT-14for BFI/RI enable, Figures 5. Wheneither or both of these switches isopened, the BFI and RI output relaysare deenergized to prevent BFI/RIcontact closures during system func-tional test.

(2) Jumpers on Interconnect Module

The jumpers shown in the chart arefactory set for 48/125 Vdc input whenthe relay is shipped. Refer to Figure6, set JMP7 and JMP9 to IN for SPT

I.L. 40-385.5

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All currents and voltages for MDAR (REL-300) sys-tem, as shown in Figure 3, are sampled and con-verted into digital quantities and input to the micro-processor where all signal processing takes place.The system timing and software design is based onthe power line frequency. The analog inputs are con-tinuously sampled 8 times per power line cycle.

The first activity of each sample period is the sam-pling of the seven analog inputs and computation ofthe Fourier and sum of squares components. Theremainder of the activity for each sample period isdetermined by the mode of operation (background orfault mode) and the number of the sample period (0or 7).

MDAR (REL-300) has an internal mode of operationwhich is generally controlled by the status of the pro-tected line. There are three normal software modes:initialization Mode is maintained for one cycle afterthe MDAR 9REL-300) relay is energized or reset;Background Mode is the normal operating mode;Fault Mode handles high-speed tripping. CalibrationMode is the fourth mode of operation which isentered after Initialization Mode if JMP6 on the pro-cessor module is installed.

5.1 FLOW CHART

The MDAR (REL-300) system software is written in80C196 Assembly Language.

The software flow is based on the sampling rate andthe 60 Hz line frequency. There are eight states percycle, which correspond to the eight sample percycle sampling rate. Movement from state to state iscontrolled by a timer. The timer is loaded with a statetime at the beginning of the state. The code executedwithin a state should be completed before the timerexpires. The software then waits for the timer to timeout.

Figure 7 shows a simplified flowchart for the relayingprograms in MDAR (REL-300). All programs areincluded in a loop, as shown, which the processorrepeats eight times per power cycle. Most functionsare performed all of the time in the backgroundmode, as shown.

An important detail not shown in Figure 7 is thatmany of the checks are broken into small parcels, sothat the whole complement of tasks is performedover an one-cycle period, eight passes through theloop. some of the checks are done more than onceeach cycle.

During non-fault operation, the programs follow theBackground Mode loop. The processor uses itsspare time to check its hardware, service the opera-tor panel and check for a disturbance in voltage orcurrent which indicates a possible fault. If a distur-bance is seen, the programs switch to fault mode, forseveral power cycles or longer, to perform phase andground unit checks for each zone and function.

The instantaneous voltage and current sampling val-ues are converted to RMS and phasor values using aFourier notch-filter algorithm. an additional dc offsetcorrection algorithm reduces overreach errors fromdecaying exponential transients.

5.2 INITIALIZAITON

The initialization routine is executed upon power upof the MDAR (REL-300) relay. All microcomputerinput and output pins and internal control registersare initialized. The system self-checks are per-formed. If a failure is detected, the failure alarm relayis de-energized and the failure code is displayed. Thesystem remains in Initialization Mode for the firstcycle of data collection. No tripping occurs during thiscycle.

Upon successful completion of the initialization rou-tine, the program jumps to the initial cycle at a sam-pling routine where input signal processing begins.

5.3 BACKGROUND MODE

MDAR (REL-300) detects faults by direct computa-tion (not analog). The relay normally operates in aBackground Mode when no fault is present.

The input currents and voltages are sampled andprocessed to compute RMS and phasor values. Thesum of squares and the sums of the Fourier coeffi-cients are updated each sample using informationfrom the previous seven samples to provide a fullcycle of data. The RMS and the phasor values of the

Section 5. DESCRIPTION OF SOFTWARE

I.L. 40-385.5

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current and voltage are updated once a cycle. Thevalues from the previous cycle are operated on whilethe present cycle of data is being collected.

The Fourier coefficients and sums, as well as thesum of squares of the inputs are calculated andaccumulated to provide RMS and phasor values ofcurrent and voltage for distance measurement andmetering display. The RMS value of the ground cur-rent is also needed for inverse-time ground protec-tion.

Several functions are performed only in BackgroundMode. The servicing of the operator interface is oneof these functions; the display is updated, pushbut-tons are acknowledged, and the LED’s are con-

trolled. Metering of the analog inputs, updating the

target information for display purposes, and checking

the validity of the settings in the nonvolatile memory

are other functions performed only in Background

Mode.

Fault detection is in effect at all time in Background

Mode. Each sampled value of current and voltage is

compared to the sampled value from the previous

cycle. If the difference exceeds the established

threshold, a fault is suspected and Fault Mode is

entered. The zone-2 and zone-3 time delay distance

protection are performed in both Background Mode

and Fault Mode.

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6.1 DISTANCE MEASUREMENTPRINCIPLE

MDAR (REL-300) consists of 3 step dis-tance zones and one optional pilot distancezone. Each zone consists of four variablemho distance units, three ØG-units and oneØØ-unit.

6.1.1 ØG fault detection

ØG fault detection is accomplished by three quadra-ture polarized phase units, ØA, ØB and ØC. Equa-tions (1) and (2) are for operating and referencequantity, respectively. The unit will produce outputwhen the operating quantity leads the referencequantity.

VXG - [IX + Ko(Io)] ZCG (1)

and (VQ) (2)

where VXG = VAG, VBG, or VCG

IX = IA, IB or IC

Io = (IA + IB + IC)/3

ZCG = PLTG, Z1G, Z2G and Z3G grounddistance reach settings in terms ofZ1L/PANG secondary ohms for ØGfaults.

Z1L, ZoL = Positive and zero sequence lineimpedances in relay ohms.

PANG, GANG= Angles in degrees of Z1L and ZoL.

Ko = Zero sequence current compensat-

ing factor

ZR = Ratio of zero to positive sequenceline impedance in absolute value.

VQ = quadrature phase voltages, i.e., VCB,VAC and VBA for ØA, ØB and ØCunits, respectively.

It should be noted that the unit may lose its direction-ality if [IX + Ko(Io)] ZCG product is higher than thephase voltage VXG. Correction of this problem is tosupervise the distance unit with FDOG unit.

6.1.2 3Ø fault detection

3Ø fault protection is accomplished by the logic ofany operation of one of the three ØG-units (ØA, ØBan ØC), plus

the 3ØF output signal from the faulted phase selectorunit.

However, for 3Ø fault condition, the equations for thecomputation of distance unit reach will be (3) and (4)instead of (1) and (2):

VXG - IXZCP (3)

and (VQ) (4)

where VXG = VAG, VBG, or VCG

IX = IA, IB or IC

ZCP = PLTP, Z1P, Z2P and Z3P zone reachsettings in terms of Z1L/PANG sec-ondary ohms for multi-phase faults.

VQ = quadrature phase voltages i.e., VCB,VAC and VBA for ØA, ØB and ØCunits, respectively. Use pre-fault volt-age for VQ when all 3 faulted volt-ages are:below 1.0 volt RMS for Z1P unit,below 7.0 volt RMS for Z2P, Z3P

and PLTP units.

6.1.3 ØØ fault detection

The ØØ-unit responds to all ØØ and ØØG faults, andsome ØG faults. Equations (5) and (6) are for operat-ing and reference quantity, respectively. It will pro-duce output when the operating quantity leads thereference quantity.

(VAB - IABZCP) (5)

and (VCB - ICBZCP) (6)

6.1.4 Characteristics

Figure 8 — ØØ/ØØG faults

=Z0L Z1L–

Z1L( )-----------------------

ZoL

Z1L-------- 1–

=

= (ZR GANG PANG1‘)–∠

Section 6. OPERATING PRINCIPLES OF SENSING UNITS

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Figure 9 — 3Ø faults

Figure 10 — ØG faults

6.2 FAULTED PHASE SELECTION UNITS

Faulted phase selection includes determining if thefault is between phases or between one or morephases and ground, and also identifies the specificphase or phases involved in the fault.

Faulted phase identification is necessary for imple-mentation of SPT for ØG faults and for providinginformation for fault location computation.

The current phasors IA, IB, IC and Io are utilized in thefault identification algorithm. When a fault occurs, thelast set of current phasors prior to the fault are savedas the pre-fault load current values.

The following conventions are used:

3Io=IA + IB + ICCalculated zero sequence currentfrom the measured post-fault current phasors

IAL, IBL, ICL,Measured pre-fault load current phasors

IA, IB, IC, 3IoMeasured post-fault current phasors

DIA, DIB, DIC,Resultant fault current phasors

To determine the resultant fault current, remove thezero sequence current from the measured post-faultcurrent and subtract the measured pre-fault load cur-rent. The resulting fault current is the sum of the pos-itive sequence current and the negative sequencecurrent of the fault.

DIA = (IA - Io) - IAL = IA1 + IA2

DIB = (IB - Io) - IBL = IB1 + IB2

DIC = (IC - Io) - ICL = IC1 + IC2

Compare the magnitude of the resultant fault currentphasors using the following table to determine thefault type.

If none of the nine fault types in the table are identi-fied, then the fault must be identified as a three-phase fault.

6.3 FORWARD DIRECTIONAL OVERCURRENTPHASE UNIT, (FDOP)

The inordinately high influence of ct lead resistancefor a low voltage MPS test with the Motor-Generatorset as one of the test sources, produces virtually a 90phase shift in the polarizing voltage with the anglebetween the sources, causing undesired operation.Even though this is an MPS-related phenomenonand would pose no problem for an actual power sys-tem, a forward directional overcurrent phase functionFDOP and logic which includes AND-144C andAND-144Ø, as shown in Figure 25, has been addedto each phase for supervising the Z1P and PLTP 3Ø-unit trip paths. The performance of the FDOP ele-ments (FDOPA, PDOPB and FDOPC) is 90 -60 ,which is similar to the directional unit of the type CRrelay, except always use prefault voltage for polariz-ing quantity. Its sensitivity is 0.5 amperes.

6.4 FORWARD/REVERSE DIRECTIONAL OVER-CURRENT GROUND UNITS (FDOG/RDOG)

There are 2 directional overcurrent ground units,FDOG (forward directional overcurrent ground) andRDOG (reverse directional overcurrent ground), inthe MDAR (REL-300) system. The operating princi-ple of these units can be selected based on the appli-cation. By scrolling the functional field to DIRU(directional unit) and selecting the ZSEQ (zero

Fault Type

AG

BG

CG

AB

BC

CA

ABG

BCG

CAG

|∆IA| > 1.5 x |∆IB| x x x

|∆IA| > 1.5 x |∆IC| x x x

|∆IB| > 1.5 x |∆IA| x x x

|∆IB| > 1.5 x |∆IC| x x x

|∆IC| > 1.5 x |∆IA| x x x

|∆IC| > 1.5 x |∆IB| x x x

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sequence) in the value field, both FDOG and RDOGunits will be polarized by zero sequence voltage 3V0.However, both units will be polarized by either zerosequence voltage 3V0 and/or zero sequence currentIP (zero sequence current from a power transformerneutral CT) if the DIRU is selected to the value ofDUAL. Both the FDOG and RDOG units will be oper-ated by negative voltage/current quantities if NSEQ(negative sequence) is selected in the value field.

6.4.1 Zero sequence polarizing ground direc-tional FDOG/RDOG units

(a) Voltage polarizing element

The voltage polarizing directional element is deter-mined by the angular relationship of the 3Io and 3Vophasors. Forward direction is identified if 3Io leads3Vo by 30 -210 . For reverse direction 3Io lags 3Vo by 0to 150 or if 3Io leads 3Vo by 0 -30 .

The sensitivity of this element is 3Io > 0.5 amp. and3Vo > 3.0 volts.

(b) Current Polarizing

The current polarizing directional element is deter-mined by the angular relationship of the Io and IPphasors, where IP is the ground current from thepower transformer neutral CT. The forward direc-tional unit will have maximum torque when Io and IPare in-phase. The reverse directional unit will havemaximum torque when Io and IP are 180 out ofphase.

The sensitivity of this element is 3Io > 0.5 amp. and IP> 0.5 amp.

6.4.2 Negative sequence polarizing grounddirectional FDOG/RDOG units

The negative sequence polarizing ground directionalunits utilize the negative sequence voltage V2 as thepolarizing quantity and negative sequence current I 2as the operating quantity. Its operation is determinedby the angular relationship of the V2 and I 2 phasors.Maximum sensitivity for the forward direction unitoccurs when V2 lags with I2 by 98 .

The sensitivity of this element is 3V2 > 1.0 volts and3I 2 > 0.5 amp.

6.5 FAULT DETECTION UNITS

MDAR (REL-300) detects faults by digital computa-tion rather than analog.

The relay normally operates in a “background mode”where it looks for phase current or phase voltage dis-turbance. Once a phase disturbance is detected, therelay enters “fault mode” and start the Z-unit compu-tations. During background mode, the four input cur-rents (IA, IB, IC and Io) and the three voltages (VA, VBand VC) are sampled, at a sampling rate of 8 timesper cycle, to test for line faults. The criteria for deter-mining a disturbance in the MDAR (REL-300) designis shown below, which comparing the instantaneoussamples taken one cycle apart:

(1) Each phase ∆I — if [IKn - I(K-1)n] > 1.0 amp.and [IKn - I(K-1)n] / I(K-1)n x 100% > 12.5%

(2) Each phase ∆V — if [VKn - V(K-1)n] > 7.0 volts.and [VKn - V(K-1)n] / V(K-1)n x 100% > 12.5%

(3) ∆Io — if [(3Io)Kn - (3Io)(K-1)n] > 0.5 amp.

where n = 1, 2, 3, 4, 5, 6, 7, 8

K = Kth. cycle

For every voltage and current disturbance the Gen-eral Start (GS) relay will pickup for 3 cycle for startingexternal (fault) recorder.

6.6 LOW VOLTAGE UNITS

There are three low voltage units (VAL, VBL and VCL)in MDAR (REL-300). Each unit senses the phasevoltage condition in the background mode. The unitcan be set from 40 to 60 volts in 1.0 volt steps. Forany phase voltage below its preset value, the LV logicwill produce a logic “1” output signal. The LV-unitsare used in CIFT and weakfeed logic in the MDAR(REL-300) system.

Note: Three separate fixed low voltageunits at 7 volts are used for theLOP logic.

6.7 BLINDER UNITS

Single blinder 21BI for 3Ø unit reach restriction onheavy load. Double blinders, 21BI and 21BO, areincluded in MDAR (REL-300) system for OS sensing.The following quantities are used for the blindersensing:

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Blinder Line Polarizing Operating

Left -j (VXG + IXRC∠PANG-90°) IX∠PANG-90°Right j (VXG - IXRC∠PANG-90°) IX∠PANG-90°

where VXG = Phase to ground voltage, VAG or VBG.

IX = Phase current in ØA or ØB.

RC = Setting of the unit. RT for inner blinder(21BI), RU for outer blinder (21BO).

PANG = the positive sequence line impedance angle.

FaultType Impedance Calculation

AG ZAG = VAG / [IA + Ko(Io)]BG ZBG = VBG / [IB + Ko(Io)]CG ZCG = VCG / [IC + Ko(Io)]AB/ABG ZAB = VAB / IABBC/BCG ZBC = VBC / IBCCA/CAG ZCA = VCA / ICAABC ZABC = VAG / IA

The distance to the fault is computed by multiplying the imaginary part of the faultimpedance times (VTR/CTR) and dividing by the distance multiplier setting (XPUD).

Distance = imag(Z) x (VTR/CTR) / XPUD

Operation occurs if the operating voltage leads thepolarizing voltage. The characteristic curves areshown in Figure 11.

Both inner and outer blinders are included in phasesA and B for OS detection on SPT operation. Innerand outer blinder reaches are determined by the set-ting of RT and RU, respectively.

6.8 FAULT LOCATOR

The fault locator feature in MDAR (REL-300) com-

putes the magnitude and phase angle of the faultimpedance and the distance to the fault in both milesand kilometers. The fault impedance is calculatedfrom the voltage and current phasors of the faultedphase(s). Thus proper faulted phase selection isessential for good fault locator results.

The impedance calculations for the various faults areas shown below:

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7.1 GENERAL DESCRIPTION

The operator panel (Figure 4) provides an integralconvenient means of checking or changing settings,and of checking relay-unit operations after a fault.Fault location, trip type, phase units which operated,and breakers which tripped are available for mostrecent 2 faults by using pushbuttons to step throughthe information. Targets from the last 16 faults arestored even if the relay is deenergized and are avail-able through remote communication only.

The operator panel contains 7 LEDs as follows:

(1) Relay in service — When this LED illuminatesthe MDAR (REL-300) relay is in service, thereis dc power to the relay and the relay haspassed the self-check and self-test. The LEDwill turned OFF if the relay has any internal fail-ure shown in the “Test” mode, and the relay tripoutput will be blocked.

(2) Settings — For read or change settings.

(3) Monitoring — The display shows three-phasevoltage, current and angle.

(4) Last Fault — When flashing, indicates new faultinformation available.

(5) Previous Fault — When last fault LED flashestwice per minute, indicates information for thefault proceeding the last fault.

(6) Value Accepted — When the “Settings” LED isalso ON, the “Value Accepted” LED flashesonly once, to indicate that a new setting valueis accepted; when the “Test” LED is also ON,the output contacts can be tested.

(7) Test — Use for verifying self-check and performfunctional test.The operator is notified that targets are avail-able by flashing LED's on the panel, plus anoutput relay contact provided to operate anexternal annunciator.

The operator can also look at non-fault voltage, cur-rent and phase angle on the display. Settings can beeasily checked as well. The display will be blockedmomentarily, every minute, for the purpose of self-check; this will not affect the relay protection function.

There are five test points on the MDAR (REL-300)relay front panel to measure power supply voltage.The test points provide measurement of the -24, +5, -12 and +12 Vdc voltages.

The serial port on the rear panel (Figure 2) is pro-vided for remote transmission of target data, remotesetting and optional oscillographic data. It also canbe used for future networking, data communications.

7.2 FRONT PANEL INTERFACE OPERATION

The operator interface consists of a vacuum displaywith four alphanumeric characters for the functionfield and four alphanumeric characters for the valuefield, seven pushbuttons, seven LED's, and five testpoints. All relay functions can be locally set, moni-tored, and tested from this front panel interface (Fig-ure 4).

7.2.1 Display Selection

The display selection pushbutton controls the type ofinformation displayed. The options include settings,metered values, two sets of fault data, and test mode.One of the five display modes is always selected andis indicated by an illuminated LED. Depressing the“DISPLAY SELECT” pushbutton changes the displayinformation to the next selection.

7.2.2 Entering Settings

The operation of the MDAR (REL-300) relay is con-trolled through the settings. To access the settings,the “DISPLAY SELECT” pushbutton should bedepressed until the “SETTINGS” LED is illuminated.The RAISE and LOWER FUNCTION pushbuttonsare depressed to scroll through the settings. TheRAISE and LOWER VALUE pushbuttons aredepressed to change the settings. When the desiredvalue appears on the VALUE display, depressing the“ENTER” pushbutton causes the displayed value tobe entered for the displayed function. The “VALUEACCEPTED” LED flashes once to indicate that thevalue has been successfully entered into the system.

7.2.3 Displaying Monitoring Data

All three-phase currents, voltages and phase anglesare available for on-line display during normal opera-tion. Conditions such as out-of-step blocking, loss-of-

Section 7. OPERATOR INTERFACE

I.L. 40-385.5

7-2

potential, and loss-of-current can also be monitored.Select the “VOLT/AMPS/ANGLE” function using the“DISPLAY SELECT” pushbutton. Scroll through themetered data using the RAISE and LOWER FUNC-TION pushbuttons. Upon initialization the display isset to show the IA current.

The phase rotation ABC or ACB is also displayed onthe monitoring mode depends on the setting of thejumper JMP3 on processor module. This feature isnot included in Version 2.6x.

7.2.4 Displaying Fault Records

The last two sets of fault data are available for dis-play. “LAST FAULT” is the data associated with themost recent trip event. “PREVIOUS FAULT” is thedata from the prior trip event. Select the desired setof target data using the “DISPLAY SELECT” push-button. Scroll through the fault data using the RAISEand LOWER FUNCTION pushbuttons. (Refer toChapter XI for more detail)

7.2.5 Display Test Mode Functions

The test display mode provides diagnostic and test-

ing capabilities for MDAR (REL-300). Information ofrelay status, A/D calibration, testing of the carriersend and receive functions for the pilot systems, andtrip relay test are among the functions provided. Toaccess the test function, the “DISPLAY SELECT”pushbutton should be depressed until the “TEST”LED is illuminated. The RAISE and LOWER FUNC-TION pushbuttons are depressed to scroll throughthe desired function. The required information willdisplay in the VALUE field. Contact output test canonly be performed when jumper JMP5 on the micro-processor module is in. (Refer to chapter VIII. Self-checking and Functional test” for more detail informa-tion).

7.2.6 16 Fault Records and IntermediateTargets.

Refer to chapter 11 for detail.

7.2.7 16 Oscillographic Records


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7.3 DISPLAY AND TARGET INFORMATION

(1) Settings Display The setting display shows the followinginformation: Display

Information / Settings Function ValueField Field

Software version VERS 2.60

*Initiate OSC storage OSC TRIP/Z2TR/Z2Z3/DVDI

Initiate fault data storage FDAT TRIP/Z2TR/Z2Z3

CT ratio CTR 30-5000, (5)

PT ratio VTR 100-7000, (5)

Rated Freq. FREQ 60, 50

CT secondary rating CTYP 5 or 1

Enable/disable readouts in primary I & V values RP YES/NO

Positive line Reactance (:/unit distance)multiplier for fault locator XPUD 0.300-1.5, in 0.001/DTYP

Fault location, displayedin Km. or miles DTYP KM or MI (miles)

Reclosing mode:TTYP1)3PT on all faults, no RI. OFF2)3PT on all faults, 1PR

with 3RI on DG fault.3)3PT on all faults, 2PR

with 3RI on DG/2D fault.4)3PT on all faults w/3RI. 3PR5)SPT on DG fault w/SRI,

3PT on MD fault w/o RI. SPR6)SPT on DG fault w/SRI,

3PT on MD fault w/3RI. SR3R

@*Single phasing limit timer 62T 0.300-5.000 in 0.05 sec. steps

*Timer for pole-disagreement SPTT 1.000-6.000 in 1.0 sec. steps

RI on Z1 trip Z1RI YES/NO



RB on BF squelch BFRB YES/NO

Remote pilot control PLT YES/NO

Pilot system selection: STYP1) 3-zone non pilot schemes 3ZNP2) Zone-1 extension scheme Z1E3) POTT or Unblocking scheme POTT4) PUTT scheme PUTT5) Blocking scheme BLK

FDOG trip delay timer FDGT 0-15, in 1 cycle steps

Blocking system channel coordination timer BLKT 0-98, in 2 ms steps

Pilot phase unit PLTP #0.01-50.00, 0.01 ohm steps

Pilot ground unit PLTG #0.01-50.00, 0.01 ohm steps

Zone-1 phase unit Z1P #0.01-50.00, 0.01 ohm steps

Zone-1 ground unit Z1G #0.01-50.00, 0.01 ohm steps

Zone-1 delay trip T1 0-15, in 1 cycle steps

* Optional@ 62T will not be available if JMP2 is not on 2-3 position

I.L. 40-385.5

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DisplayInformation/Settings Function Value

Field Field (note 1)

Zone-2 phase unit Z2P # 0.01-50.00, 0.01 ohm stepsZone-2 phase timer T2P 0.10-2.99,BLK,0.01sec.stepsZone-2 ground unit Z2G # 0.01-50.00, 0.01 ohm stepsZone-2 ground timer T 2G 0.10-2.99,BLK,0.01sec.steps

Zone-3 phase unit Z3P # 0.01-50.00, 0.01 ohm stepsZone-3 phase timer T3P 0.10-9.99,BLK,0.01sec.stepsZone-3 ground unit Z3G # 0.01-50.00, 0.01 ohm stepsZone-3 ground timer T3G 0.10-9.99,BLK,0.01sec.stepsZone-3 direction Z3FR FWD/REV

Z1L impedance angle PANG 40-90, in 1.0 degree stepsZOL impedance angle GANG 4 0-90, in 1.0 degree stepsZOL/Z1L ZR 0.1-7.0, in 0.1 steps

Low voltage units LV 4 0-60, in 1.0 volt steps.Low set phase o/c unit IL 0.5-10, in 0.1 amp stepsMed set phase o/c unit IM 0.5-10, in 0.1 amp stepsLow set ground o/c unit IOS 0.5-10, in 0.1 amp stepsMed set ground o/c unit IOM 0.5-10, in 0.1 amp stepsHigh set phase o/c unit ITP # 2.0-150.0, 0.5 amp stepsHigh set ground o/c unit ITG # 2.0-150,0, 0.5 amp steps

Out-of-step block zone-1 OSB1 YES/NOOut-of-step block zone-2 OSB2 YES/NOOut-of-step block pilot OSBP YES/NOOS & OS override timers OSTM 500, 1000 msOSB inner blinder RT 1.00-15.00, 0.1 ohm stepsOSB outer blinder RU 3.00-15.00, 0.1 ohm steps

Directional ground units DIRU ZSEQ, NSEQ, DUALGround backup time curves GBCV # CO-2, CO-5, CO-6, CO-7,

CO-8, CO-9 and CO-11.Ground backup setting GBPU 0.5-4.0, in 0.1 amp stepsGround backup time dial GTC 1-63, in 1.0 stepsChoice of directional or non-directional ground backup GDIR YES/NO

CIF trip CIF YES/NO

LLT trip LLT YES/FDOG/NO

LOP block LOPB YES/NO

LOI block LOIB YES/NO

Trip alarm seal-in AL2S YES/NO

Remote setting SETR YES/NO

Real time clock TIME YES/NO1) set year YEAR 1980-2079,in 1 year steps2) set month MNTH 1-12, in 1 month steps3) set day DAY 1-31, in 1 day steps4) set week day WDAY SUN/MON/TUES/WEN/

THUR/FRI/SAT5) set hour HOUR 1-24, in 1 hour steps6) set minute MIN 1-60, in 1 minute steps

* Optional, # use “OUT” for disabling this unit.

Note: When the CTYP is set at 1 ampere, the range of the following functions is as shown below:

Z1P/Z1G/Z2P/Z2G/Z3P/Z3Gand PLTP/PLTG 0.05-250.00, in 0.05 ohms stepsITP/ITG 0.4-30.0, in 0.1 amp. steps

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(2) Monitoring DisplayThe metering group display shows the following information.

DisplayInformation Function Value

Field Field (note)

Phase A current (mag.) IA numerical, A“ (ang.) ∠IA deg.

Phase A voltage (mag.) VAG numerical, v“ (ang.) ∠VAG deg.

Phase B current (mag.) IB“ (ang.) ∠IB

Phase B voltage (mag.) VBG“ (deg.) ∠VBG

Phase C current (mag.) IC“ (ang.) ∠IC

Phase C voltage (mag.) VCG“ (ang.) ∠VCG

Date DATE XX.XX (month.day)Time TIME XX.XX (hour.minute)Local/Remote Setting SET LOC/REM/BOTHCarrier Receiver-1 RX-1 YES/NOLOP Indication LOP YES/NOLOI indication LOI YES/NOOut-of-step block OSB YES/NO

* Optional

Note: All displayed phase angles are referred to V A as reference.

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(3) Fault Data Display

The MDAR (REL-300) saves the latest 16 fault records, but only the latest two fault records can beaccessed from the front panel. For complete 16 fault records, one of the communication interfacedevices are required.

Each set of fault target record display shows the following information:

Display

Information Function ValueField Field

Fault occurred at:1.date DATE XX.XX (month.day)2.year YEAR XXXX3.time TIME XX.XX (hour.minute)4.second SEC XX.XX (second)

Fault type FTYP AG/BG/CG/AB/BC/CAABG/BCG/CAG/ABC

BKR. #1 DA tripped BK1A YES/NOBKR. #1 DB tripped BK1B “BKR. #1 DC tripped BK1C “


Zone-1 phase tripped Z1P YES/NOZone-1 ground tripped Z1G “

Zone-2 phase tripped Z2P “Zone-2 ground tripped Z2G “


Pilot phase tripped PLTP “Pilot ground tripped PLTG “

High set phase tripped ITP “High set ground tripped ITG “

Close-into fault trip CIF “

Load-loss tripped LLT “

Ground backup tripped GB “

*Sec. fault tripped(SPF) SPF “*62T tripped 62T “

* Optional functions for single-pole trip.

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Field Field (note)

Fault location Z In ohmsFault Z angle FANG numericalFault distance DMI or DKM In miles or KM

Prefault load current PFLC numerical, APrefault phase voltage PFLV numerical, VPrefault load angle LP numerical, deg.

Carrier send SEND numerical,RCVR #1 RX1 numerical,Fault voltage VA (mag.) VPA numerical, V(ang.) ∠ VPA numerical, deg.

Fault voltage VB (mag.) VPB numerical, V(ang.) ∠VPB numerical, deg.

Fault voltage VC (mag.) VPC numerical, V(ang.) ∠VPC numerical, deg.

Fault voltage 3VO(mag.) 3VO numerical, V(ang.) ∠3VO numerical, deg.

Fault current IA (mag.) IPA numerical, A(deg.) ∠IPA numerical, deg.

Fault current IB (mag.) IPB numerical, A(deg.) ∠IPB numerical, deg.

Fault current IC (mag.) IPC numerical, A(deg.) ∠IPC numerical, deg.

Fault current 3I0(mag.) 3IO numerical, A(deg.) ∠3IO numerical, deg.

Pol. current IP (mag.) IP numerical, A(deg.) ∠IP numerical, deg.

* Optional

Note: All displayed phase angles are referred to VA as reference.

Note: The “Relay In Service” LED indicates the MDAR (REL-300)ms system is in-service. It will come onwhen the dc is applied and after the system is initialized.

(4) Test Functions Display

Five functions are available in the test function mode. They are: STAT, ADC, RS1, TK and TRIP.

STAT The STAT is the relay self-check status. MDAR (REL-300) jumps to the test mode status display(STAT) to show the cause of the problem. A zero value indicates that no self-check failure hasoccurred. A nonzero hex byte form value indicates hardware or software failed. Refer to ChapterVIII for more detail.

ADC The ADC value display is for use in calibration of the analog input to MDAR (REL-300) and is onlyvisible when MDAR (REL-300) is in calibration mode (JMP6 on processor module installed). Referto Appendix E for calibration.

RS1, TK and TRIP

These selections are for functional tests. When the selector is in the test mode,

scroll the function field by the raise pushbutton. The value field display showsRS1, (Carrier receiver #1), and TK (Carrier send). Refer to Chapter VIII for moredetailed information.

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7-8

If jumper JMP5 on the processor module is set to IN position, the following tencontacts can be selected for testing. Refer to Chapter VIII for more detailedinformation.

TRIP RELYBFI RELYRI1 RELYRI2 RELYRB RELYAL1 RELYAL2 RELYGS RELYSEND RELYSTOP RELY

7.4 16 FAULT RECORDS AND INTERMEDIATE TARGETS.


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8.1 SELF-CHECKING

Self-testing is a major benefit of microprocessor-based relays. At all times, MDAR (REL-300) monitorsits ac input subsystems using multiple A/D convertercalibration check inputs, plus loss-of-potential andloss-of-current monitoring (as described in ChapterIX). Failures of the converter, or any problem in a sin-gle ac channel which unbalances nonfault inputs, arealarmed. The self-checking covers the followingareas:

(a) Analog Front End Test

One of the inputs to the analog multiplexer is atest input. This input voltage can be switchedbetween +2.5 V and -0.3 V for input to the A/Dconverter. Periodic testing of these voltagestests the analog front end for proper operation.In this way the multiplexer, sample/hold, rang-ing circuitry, and A/D converter are tested.

(b) Program Memory Checksum

Immediately upon power-up the relay executesa complete ROM checksum of program mem-ory. During operation, the MDAR (REL-300)relay continually computes and verifies the pro-gram memory checksum.

(c) Power-up RAM Test

Immediately upon power-up the relay does acomplete test of the RAM data memory.

(d) Nonvolatile RAM Test

All settings for the system operation are storedin non-volatile RAM in three identical arrays.These arrays are continuously checked by theprogram. If all three array entrees disagree witheach other, a non-volatile RAM failure isdetected.

(e) Processor Tests

Several tests are included to verify the opera-tion of the microprocessor. On power-up, theprocessor I/O status registers are checkedwhile they are still in a known state. Other testsperformed both at power-up and during normaloperation are listed below:

• Tests processor flags, stack, and timer.• Tests program counter, execution time, and RAM.

• Tests addition and subtraction.For failures which do not disable the processor,MDAR (REL-300) jumps to the TEST mode statusdisplay (STAT) to show the cause of the problem. Thecause of the problem is represented by their corre-sponding bits (zero thru 6) in the value field.

Bit 0 External RAM FailureBit 1 EEPROM warningBit 2 ROM (EPROM) checksum errorBit 3 EEPROM Failure (Non-Volatile memory)Bit 4 Analog Input Circuit FailureBit 5 Processor FailureBit 6 Wrong setting on JMP2 for single-pole trip

or programmable output contactselections.

All bits are expressed in a HEX byte form. For exam-ple: If the display shows “STAT 1B”, whose binaryrepresentation is 0001 1011, the relay failed the self-test in the area of External RAM (bit 0), EEPROM(one-out-of-three failure, bit 1), EEPROM (two-out-of-three failure, bit 3) and Analog Input Circuit (bit 4).Normally, the test mode should show “STAT 0". Thismeans that the relay passes the self-test routines.

Bit 6 is for the setting discrepancy detection. Forexample, if the order information calls for single-poletrip option and the jumper #2 on the processor mod-ule is on position “1-2” which is for 3-pole trip, theMDAR (REL-300) will give the error of “TEST 40".

8.2 LOP AND LOI CONDITIONS

MDAR (REL-300) contains loss-of-potential (LOP)and loss-of-current (LOI) logic which monitors theanalog inputs. The loss of a voltage or current inputwhich is not caused by a fault condition enables theGS alarm relay. In addition, tripping is disabled dur-ing a LOI condition if the LOIB setting is set to YES.However, only the distance measurement units aredisabled during a LOP condition if the LOPB settingis set to YES. The LOP and LOI status displays areincluded in the monitored data.

8.3 OUTPUT CONTACT TESTS

The output contact test, a “Push-to-close” approach,is included in MDAR (REL-300) for checking all out-put relay contacts. It is designed for a bench test only.The test is for used to verify the operation of the con-

Section 8. SELF-CHECKING AND FUNCTIONAL TEST

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tacts of the TRIP, BFI, RI1, RI2, RB, AL1, AL2, GS,Carrier SEND and Carrier STOP functions. It is sup-plementary to the self-check because the micropro-cessor self-check routine cannot detect the outputhardware.

If it is not a bench test, all the red-handled FTswitches should be opened before performing thetest to avoid the undesired tripping during tests. How-ever, due to the opening of the connection between2FT-14 terminals #13 and #14, the contacts of BFI,RI1 and RI2 will not be verified.

For performing the output contact test:

(1) Remove JMP10 (spare on the processormodule) and place it in the JMP5 posi-tion.

(2) Change the LED mode to TEST andselect the tripping function field and thedesired contact in the value field.

(3) Push the ENTER button; the ENTERLED should be ON. The correspondingrelay should operate when the ENTERbutton is pressed.

(4) Remove JMP5 and replace it on JMP10.

8.4 FUNCTIONAL TEST

The functional test simulates the channel conditionfor verifying the relay system. The procedure of thetest is:

(1) Change the LED mode to TEST andselect the following desired function field:RS1, TK.

(2) Push the ENTER button; the ENTERLED should be ON. The correspondingfunction of RS1 (receiver 1) or TK (trans-mitter keying) will be simulated for therelay system.

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9.1 LOSS-OF-POTENTIAL SUPERVISION (LOP)

The ac voltage monitoring circuit is called loss-of-potential circuit.

In order to prevent undesirable tripping due to thedistance unit(s) pickup on loss-of-potential, logic (lowvoltage and not VI) and (Vo and not Io) are includedin MDAR (REL-300) design, as shown in Figure 12A.The low voltage and Vo units for the LOP logic areset at a fixed value of 7 volts. Under loss-of-potentialcondition, low voltage (or Vo) and not VI (or Io) satisfyAND-1. The output signal of AND-1 starts the 8/500ms timer. The timer output will satisfy AND-1C ifthere is no output from AND-1B. The output signal ofAND-1C will block all the distance unit tripping pathsvia AND-2, AND-3, AND-4, AND-5, AND-6, AND-172(also blocks AND-191 and AND-187 for pilot sys-tems) if LOPB is set to “YES”. The LOPB blockingfunction can be disabled by selecting the LOPB valuedisplay to NO.

The output of the LOP timer will turn on the non-memory LOP indicator on the metering display dur-ing the LOP condition via AND-1F after 500 msdelay. This output is also connected to the failurealarm output relay GS (Alarm-3).

In selecting the LOPB to “YES”, the intent is to blockall the distance units from tripping should a LOP con-dition exist. However, for a condition as shown in Fig-ure 12B, a single-end source energizes two parallelcircuits without pre-fault load current. The MDAR(REL-300) at the remote end B of the protected linemay fail to trip for an internal fault near the source-end A, because its LOP sets up before the terminal Atrips. This is because the relay at B sees no current,but sees a low voltage condition before circuitbreaker A opens.

Also, for a condition as shown in Figure 12C, anevolving fault at 50% location with symmetricalsource impedances, MDAR (REL-300)'s at both Aand B will not trip if LOPB is selected to “YES”,because neither MDAR (REL-300) sees a currentchange (or no Io) on the protected line to set up theLOPB logic before the second fault is applied.

Logic AND-1A,-1B,-1C,-1E and OR-1D, and 150/0, 0/3500 ms timer circuits in Figure 12A are for solvingthese problems. This logic unblocks the LOPB circuitand provides a 3500 ms trip window for the distanceunits to trip if the fault current is detected within 150ms after LOP has been set up. The 150 ms timer canbe extended to 500 ms if a jumper (JMP3) on theMicroprocessor module is installed.

9.2 MONITORING OF AC CURRENT (LOI)

The ac current monitoring circuit is similar to the LOPlogic, except using IOM and not Vo as a criterion, asshown in Figure 13. Under a ct short circuit or opencircuit condition, IOM and not Vo satisfies AND-23.The LOI output signal from AND-23 starts the 500/500 ms timer. The output of the timer will turn on thenon-memory LOI indicator on the metering displayduring the LOI condition. This output is also con-nected to the failure alarm output relay GS (AL-3).The LOI signal also can be used to block the MDAR(REL-300) trip outputs under LOI condition if theLOIB (loss-of-current block) is selected to YES.

9.3 OVERCURRENT SUPERVISION(Figure 14)

The MDAR (REL-300) distance units do not requireovercurrent supervision, because the relay normallyoperates in a background mode. They will not startthe zone-1 and pilot impedance computation until aphase current or a phase voltage disturbance isdetected. This approach can minimize the load prob-lem on setting the phase overcurrent units. However,in order to meet the traditional practice, a medium setphase overcurrent unit IM (IAM or IBM or ICM) hasbeen added to MDAR (REL-300) versions 2.10/2.60to supervise Z1P/Z2P/Z3P/PLTP trip functions, asshown in Figure 14. This unit should not be set tolimit the zone-3 reach, and traditionally should be setabove the load current.

For increasing the security, the application of LOPBsupervision function is still normally recommended.

For coordination purposes, the ground trip units Z1G,Z2G, Z3G, PLTG, and FDOG are supervised by themedium set ground overcurrent unit IOM, except theZ3G/RDOG units (for carrier start on blockingscheme, and for reverse blocking on permissivescheme) are supervised by the low set IOS. The Iom

Section 9. OPERATION OF MDAR (REL 300) BASIC FUNCTIONS

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and Ios settings must be coordinated with oneanother.

Besides the above supervisions, the MDAR (REL-300) is supervised by a different kind of faulted phaseselector signal on each trip path. The faulted phaseselector uses current only(I1 + I2) approach. For ØØ - unit tripping there mustbe I2 present.

9.4 ZONE-1 TRIP

When the MDAR (REL-300) functional display“STYP” is selected to “3ZNP” it will perform 3-zonenon-pilot functions.

For Zone-1 phase faults, the Z1P unit will see thefault and operate. As shown in Figure 15. Outputs ofZ1P, IM plus the operation of FDOP, if applied, satis-fies AND-2 and provides a high speed trip (HST) sig-nal from OR-2 to operate the trip output telephonerelay. The trip circuit is monitored by a seal-in reedrelay S, which is in series with each trip contact in thetripping circuits. The S relay will pick up if the trip cur-rent is higher than 0.5 amp. The operation of theseal-in contact “S” (i.e. after breaker trip coil hasbeen energized) provides the trip seal-in signalTRSL. It feeds back to OR-4 and AND-8 to hold thetrip relay in operation until the breaker trips and the52b contact opens (not shown in Figure 15). The tripcontact and the TRSL signal can be delayed dropoutby 50ms after the trip current is removed, providingJMP4 on the microprocessor board is connected.The TRSL signal from AND-8 plus the output signalfrom AND-2 turn on the Zone-1 phase trip indicatorZ1P. The breaker trip and Zone-1 phase trip indica-tors are sealed-in. They can be reset only after man-ually pushing the RESET pushbutton on the frontpanel, or through remote communication. The flash-ing LED will be reset, but the fault information will stillremain in memory.

The Z1P 3ø trip logic AND-131 is also supervised bythe selectable OSB logic when the OSB1 is selectedto “YES”.

Z1P logic AND-2 is also supervised by the FDOP(forward directional overcurrent phase unit) when theOSB1 or OSB2 or OSBP is selected to “YES” formore security on some special power system appli-cations (Refer to Chapter XI, paragraph G for a moredetailed explanation).

Similar operations function for Zone-1 single-phase-to-ground faults. The Z1G unit sees the fault and

operates along with the IOM and FDOG units, satisfy-ing AND-3. Tripping is initiated via OR-2 with Zone-1ground trip Z1G indication. Logic AND-3 is alsosupervised by the signal of RDOG (reverse direc-tional overcurrent ground) for security.

A two-out-of-three “leading phase blocking” logic isincluded for solving the overreach problem of the sin-gle-phase ground distance units which may respondto a ØØG fault.

The Z1G unit is also supervised by the signal ofunequal-pole- closing.

The T1 timer, as shown in Figure 15, provides timedelay on Z1P/Z1G trip if required. The range of T1timer is 0 to 15 cycles in 1.0 cycle steps. Normally,the T1 timer should be selected to zero time delay,unless it is needed. For example, when using MDAR(REL-300) as a non-pilot 3PT backup with anothersystem operated on SPT mode, set MDAR (REL-300) Zone-1 with delay.

HST signal also is connected to the reclosing initia-tion logic.

Either or both Zone-1 phase and Zone-1 groundfunction(s) can be disabled by selecting the Z1P and/or Z1G to OUT.

9.5 ZONE-2 TRIP

For Zone-2 phase faults, the Z2P unit will see thefaults, plus the output of IM, operates the Zone-2phase timer T2P. Z2P output plus the T2P timer out-put satisfy AND-4 as shown in Figure 16. AND-4 out-put provides time delay trip signal TDT via OR-3.Signal TDT picks up OR-4 (Figure 15) and operatesthe trip relay. The tripping and targeting are similar asdescribed in Zone-1 trip except with Zone-2 phasetime delay trip Z2P indication.

Similar operation occurs for Zone-2 single-phase-to-ground faults. The Z2G unit sees the fault and oper-ates. This plus the operation of the IOM, FDOG andT2G, satisfies AND-5, and provides the TDT signalvia OR-3 with Zone-2 ground time delay trip indicatorZ2G.

Zone-2 3ø unit is supervised by the selectableOSB2.

The single phase ground distance units may respondto a ØØG fault. The output of the Z2G unit plus theoperation of the ØØ - selection will trip the Z2P viaOR-157, T2P and AND-18. Leading phase blockingis unnecessary for an overreach zone device.

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TDT signal can be connected to the reclosing blocklogic.

Either or both Zone-2 phase and Zone-2 groundfunction(s) can be disabled by selecting the Z2P and/or Z2G to OUT; or can be disabled by selecting theT2P and/or T2G to BLK.

9.6 ZONE-2 TRIP

For Zone-3 phase faults, the Z3P unit (forward orreverse looking, depending on the Z3FR set to FWDor REV) will see the faults and operate the Zone-3phase timer T3P. The Z3P output plus the T3P timeroutput satisfy AND-6 as shown in Figure 17. AND-6output provides time delay trip signal TDT via OR-3.Signal TDT picks up OR-4 (Figure 15) and operatesthe trip relay. The tripping and targeting are similar toZone-1 trip, except with zone-3 phase time delay tripZ3P indication.

Zone-3 3ø unit is not supervised by the OSB logic.

For Zone-3 single-phase-to-ground faults, the Z3Gsees the fault and operates. This plus the operationof the IOM, satisfy AND-7. This provides the TDT sig-nal, then trips via OR-3 with zone-3 ground timedelay trip indicator Z3G. TDT signal can be con-nected to the reclosing block logic. For security, theZ3G unit is also supervised by the signal of RDOGwhen it is set for reverse looking (or by the signal ofFDOG when it is set for forward looking) via logicOR-171B and AND-171A as shown in Figure 17.

Either or both Zone-3 phase and Zone-3 groundfunction(s) can be disabled by selecting the Z3P and/or Z3G to OUT; or by selecting the T3P and/or T3Gto BLK.

9.7 DIRECTIONAL INSTANTANEOUSOVERCURRENT TRIPS

The directional instantaneous overcurrent units IAH,IBH, ICH and IOH are supervised by the FDOP (A, Band C) for phases and by FDOG for ground. Theseunits are normally set high to detect those faultswhich occur in the Zone-1 area. Therefore, their trip-ping will occur via OR-2 for HST, as shown in Figure18. The use of directional supervision will minimizesome setting difficulties in applications. The setting ofLOPB has no effect to the high-set trip functionexcept the units will become a non-directional duringLOP condition if the LOPB setting is set to YES.These high-set trip functions can be disabled by set-ting the ITP (phase) and/or ITG (ground) to OUT.

9.8 CLOSE-INTO-FAULT TRIP

In order to supplement distance unit operation whenthe circuit breaker is closed into a fault and line sidepotential is used. The CIF close-into-fault trip circuit,as shown in Figure 19, includes logic AND-22, OR-3and 100/180 ms and 16/0 ms timers. Logic AND-22is satisfied and produces a trip signal for 180 ms aftercircuit breaker closing (52b contact opened) if theovercurrent unit(s), IAL, IBL, ICL or IOM, operate OR-11, and if any phase voltage is below the preset levelof the LV-units (OR-222A). Tripping will be via OR-3,with RB and CIF target.

The application of the “close-into-fault” function isselected by the setting of the CIF to YES.

9.9 UNEQUAL-POLE CLOSING LOAD PICKUPCONTROL

The ground units may pick up on a condition of loadpickup with unequal breaker pole closing. The highspeed trip ground units Z1G and FDOG/IOM shouldbe supervised under this condition. This can beachieved, as shown in Figure 20, by inserting a 0/50ms timer and controlling by the 52b signal to super-vise the Z1G trip path AND-3 (Figure 15) and FDOG/IOM trip path AND-188 (Figures 26 and 34). It shouldbe noted that the 50 ms time delay will have no effecton a normal fault clearing.

The ground distance unit PLTG is less sensitive asthe FDOG, it is not need to have this supervising cir-cuit.

On internal ground faults, if the mechanical actuatorof the circuit breaker operates, but the arc does notextinguish (e.g. due to low gas pressure), the closingaction of the 52b contact, connected to MDAR (REL-300), will reset the Z1G trip path AND-3, and ulti-mately, the BFI contact. This may introduce interrup-tion to the BF scheme if BFI logic does not provideseal-in circuit. The AND-3C logic in Figure 20 willsolve this problem.

9.10 INVERSE TIME DIRECTIONAL OR NON-DIRECTIONAL OVERCURRENT GROUNDBACKUP (GB)

The overcurrent ground backup unit GB is to supple-ment the distance ground protection on high resis-tance ground faults. Its selectable time characteristiccurves, as shown below, are similar to the conven-tional CO relays.

CO-2 Short time curve

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Curve No. T0 K C P R

CO2 111.99 735.00 0.675 1 501C05 8196.67 13768.94 1.130 1 22705CO6 784.52 671.01 1.190 1 1475CO7 524.84 3120.56 0.800 1 2491CO8 477.84 4122.08 1.270 1 9200CO9 310.01 2756.06 1.350 1 9342CO11 110.00 17640.00 0.500 2 8875

CO-5 Long time curveCO-6 Definite time curveCO-7 Moderately inverse time curveCO-8 Inverse time curveCO-9 Very inverse time curveCO-11 Extremely inverse time curve

As shown in the setting table, the time curve can beselected by using the “GBCV” setting, the time dial isset by the “GTC” value. The following equation canbe used to calculate the trip time for all CO curvesfrom CO-2 to CO-11:

GBPU = Pickup current setting (0.5 to 4.0A)GTC = Time curve dial setting (1 to 63)T0, K, C, P and R are constants, and are shown asbelow:

The GB function can be set as either directional ornon-directional by setting the “GDIR” to YES or NO.

T sec( ) T 0K

3I0 C–( )P---------------------------+GTC24000---------------for 3I0> 1.5= =

T (sec)R

3I0 1–( )---------------------GTC24000--------------- for 1 3I0 1.5<<=

where 3I0

IFGBPU------------------=

set to DUAL position. However, the GB-unit will becontrolled by the negative sequence voltage and cur-rent polarized element if the value field is selected toNSEQ (negative sequence). The pickup value of theovercurrent unit is controlled by the “GBPU” setting.The unit can be disabled by selecting the “GBCV” toOUT.

9.11 ZONE-1 EXTENSION

This scheme provides a higher speed operation onend zone faults without the application of pilot chan-nel.

If the MDAR (REL-300) functional display “STYP” isselected to Z1E, the Z1P/Z1G unit will provide twooutputs. One is overreach (reach to 1.25 times thezone-1 setting) and one is the normal zone-1 reach.A single shot instantaneous reclosing device shouldbe used when applying this scheme. The targetsZ1P/Z1G will indicate either zone-1 trip and/or Z1Etrip operations. The other functions, such as Z2T,Z3T, ac trouble monitoring, overcurrent supervision,IT, CIF, unequal-pole closing load pickup control,load-loss acceleration trip, etc. would remain thesame as in the basic scheme (3ZNP).

For a remote internal fault, (Figure 22), either Z1P orZ1G will see the fault since they overreach to

The directional GB function uses the torque controlapproach as indicated in Figure 21. The directionalelement can be selected with either zero sequenceor negative sequence as a polarizing quantity,depending on the application. By scrolling the func-tional field to DIRU (directional unit) and selectingZSEQ in the value field, the GB-unit will be controlledby the zero sequence voltage polarized element. TheGB-unit will be controlled by either the zerosequence voltage 3Vo polarized element and/or thezero sequence current IP polarized element (currentfrom a power transformer neutral CT) if the DIRU is

1.25(Z1P/Z1G), high speed tripwill be performed via the normalZ1T path (Figure 15) AND-2 (orAND-3) and OR-2. HST signaloperates the instantaneousreclosing scheme. The breakerrecloses and stays closed if thefault is automatically cleared.

Target Z1P and/or Z1G will be dis-played. Once the breaker trip cir-cuit carries current, it operates the

logic OR-5 (not shown), produces output signalTRSL, and satisfies logic AND-26 for 5000 ms (Fig-ure 25). The output signal of AND-26 will trigger theZ1P/Z1G reach circuit, constricting their reachesback to the normal Zone-1 for 5000 ms. During thereach constricting periods, if the breaker is reclosedon a Zone-1 permanent fault, it will trip again. If thebreaker is reclosed on an end-zone permanent fault,the normal Z2T will take place.

For a remote external fault, either Z1P or Z1G will seethe fault since they are set to overreach. High speed

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trip will be performed. HST signal operates theinstantaneous reclosing scheme. The breakerrecloses and stays closed if the fault has been iso-lated by the adjacent line breaker.

However, if the adjacent line breaker fails to trip, thenormal remote back up will operate.

9.12 SELECTABLE LOSS-OF-LOADACCELERATED TRIP (LLT)

The load loss accelerated Zone-2 trip logic sensesremote 3-pole clearing on all faults except 3Ø tocomplement or substitute for the action of the pilotchannel, speeding up trip at the slow terminal. Thelogic includes AND-24, AND-25, OR-13, 0/32 and the10/0 ms timers, as shown in Figure 23. Under normalsystem conditions, 3-phase load currents are bal-anced, and the low set overcurrent units IAL, IBL, ICLsatisfy both AND-24 and OR-13. On internal endzone faults, Z2P, Z2G and/or FDOG/IoM picks up andsatisfies the third input to AND-25 via OR-6. How-ever, the signal from AND-24 is negated to AND-25,therefore, AND-25 should have no output until theremote end 3-pole trips.

At this time the local end current will lose one or twophases, depending on the type of fault (except 3-phases), and AND-24 output signal changes from “1”to “0”, satisfying AND-25. After 10 ms this outputbypasses T2 timer and provides speedup Zone-2trip. The 10/0 ms time delay is for coordination onexternal faults with unequal pole clearing. The 0/32ms timer is needed for security on external faults withno load current condition. Targets LLT will turn onafter an LLT trip.

The LLT function is selected by the setting of “YES,FDOG, NO”, where YES = LLT with Z2 supervision;FDOG = LLT with both Z2 and (FDOG/IOM) supervi-sion; and NO = LLT function is not used.

LLT is not recommended for 3-terminal line applica-tion due to difficulty in determining proper setting ofIL and complicated infeed from the third terminal.

9.13 PROGRAMMABLE RECLOSING INITIATION(Figure 24)

The MDAR (REL-300) system provides the followingcontact output for reclose initiation (RI) and recloseblock (RB) functions:

RI1, used for reclose initiation on single pole trip.RI2, used for reclose initiation on 3-pole trip.RB, used for reclose block.

The operation of RI1, RI2 and RB contacts is con-trolled by the setting of the programmable reclose ini-tiation logic as shown in Figure 24. The operation ofeither RI1, RI2 or RB must be confirmed by the signalof TRSL, which is the trip output of MDAR (REL-300)operation.

The External Pilot Enable Switch (refer to Figure 6,terminals 9 and 10 on TB-5), is used for externallyenabling the pilot system.

The PLT setting is similar to the external pilot enableswitch, except it is set from the front panel (orremotely set via the communication interface).

For pilot MDAR (REL-300) with supporting non-pilotfunction, a most popular reclose initiation practice isto have reclosing initiation on high speed trip (pilot,Zone-1 and high set) only. Referring to Figure 24, thiscan be programmed by closing the external pilotenable switch and selecting PLT and Z1RI to YES.AND-84 will produce logic to operate the RI2 relaywhen receiving signals from TRSL and AND-89. Theuse of Z1RI signal to supervise the AND-84 providesa flexibility for disabling RI, if needed, when pilot is in-service. The program is further controlled by theTTYP setting.

TTYP set at OFF — 3PRN provides no output,therefore, RI2 will not operate.

TTYP set at 1PR — 3PRN will provide output “1”on ØG faults only (via OR-100 andAND-51A), RI2 will operate.

TTYP set at 2PR — 3PRN will provide output “1”on ØG fault or ØØ faults (via OR-100B and AND-51B), RI2 willoperate.

TTYP set at 3PR — 3PRN will provide output “1”on any type of fault (via OR-51),and RI2 will operate.

The Z1RI, Z2RI AND Z3RI settings combining withthe logic of AND-62B, -62C, -62D and OR-62 providefor programming applications where the reclose initi-ation on Zone-1, Zone-2 or Zone-3 trip is desired ona non-pilot MDAR (REL-300) system. AND-62A iscontrolled by the signal 3PRN, therefore, the settingof 1PR, 2PR and 3PR also affects the Z1RI, Z2RIand Z3RI program.

In general, the RB relay will operate on TDT (timedelay trips) or OSB (out-of-step block condition).However, it will be disabled by the setting of Z1RI,

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Z2RI or Z3RI signal via OR-62 and AND-86.

9.13.1 Logic for RB on BF squelch

For a pilot system, the BFI signal can be used to stop(for a blocking system) or start (for permissiveschemes) the carrier channel to allow far end line ter-minals to trip in the event a breaker close to an exter-nal fault fail to open. The problem is how to inhibit itreclosing on those terminals, to limit damage.

MDAR (REL-300) solves this problem at the far endterminals by the Reclose Block on Breaker FailureSquelch logic in the RI/RB software. When thebreaker fails to trip, the BFI logic squelches the chan-nel to continuous permissive signal, or stops theblocking signal. This is done after some time delay.The relay at the far end, having sensed the externalfault in the forward direction, sees the permissive sig-nal (or stoppage of blocking signal) much later than itwould for a normal pilot trip operation initiated byrelay forward-looking elements at the end closer tothe fault. This time delay is used to differentiatebetween a faster normal pilot trip and the slowerproblem-related pilot trip initiated by BFI, and to blockreclosing in the later case.

This logic is shown in Figure 24, which includes theAND-61A and a 132/0 ms timer. The logic at the farend terminal will initiate RB and inhibit RI) at 132 ms(about 8 cycles) after the fault is detected by theoverreaching PLTP or PLTG element, if the pilot isenabled and the TRSL signal is received on anythree-pole trip operation. If the fault is cleared beforethe 132 ms expiration of the timer, normal reclosingwill occur.

9.13.2 For Single-pole-trip and pilot applications

The RI1 relay is provided for single-pole trip scheme,which is controlled by the TTYP setting of SPR andSR3R. Refer to Chapter X, Operation of MDAR(REL-300) Optional Functions for the programmablereclose initiation on single-pole trip or pilot applica-tions.

9.14 POWER SWING BLOCK SUPERVISION,OSB

The Out-of-step blocking (OSB) logic in MDAR (REL-300) is a dual blinder scheme. It contains two blinderunits, providing 4 blinder lines. The nature of the logicshown in Figure 25 is that the outer blinder 21BOmust operate 50 ms or more ahead of the innerblinder 21BI, in order for an OS condition to be identi-fied.

The OS logic is also supervised by the medium setphase overcurrent signal (AND-122 on Figure 25).The OSB signal is a negated input to the AND-131(Z1P), AND-147 (Z2P), and AND-176 (PLTP) forsupervising the 3-phase distance trip.

The OSB signal is also applied to the reclosing logicfor initiating RB.

The OSB logic as shown in Figure 25 is proposed byEPRI/China. Its design is based on the power systemoperation practices and experiences in China. Itincludes the following unique features:

• OSB is not applied to zone-3.

• OSB for zone-1, zone-2 and pilot is selected bythe setting of OSB1, OSB2 and OSBP,respectively.

• Use separated timers OSOT1 and OSOT2 inzone-1 and zone-2 logic for out-of-step overridetripping, as shown in Figure 25.

• An selectable OSTM timer setting, range 500 or1000 ms, is provided for the logic. This timer willbe used for the following features.

• In order to ensure continuously OS block to theZ-units from tripping on the second and thefollowing OS cycles where the swing rate may befaster than the previous cycles, the modified OSlogic provides that once the out-of-step conditionis identified, the reset time of the output signalfrom the OS timer will be controlled by the presettime of OSTM.

• Provide logic for blocking zone-1 and pilot (notzone-2 and zone-3) 3-phase units on severeexternal fault with delay clearing (e.g. breakerfailure condition). This logic included the 21BIsignal, the 200/OSTM timer, and OR-122A, OR-201A, as shown in Figure 25.

9.15 Communications

Refer to chapter XI for detail.

9.16 Fault Records and Intermediate Targets

Sixteen records and targets are stored. Refer tochapter XI for detail.

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7.1 GENERAL DESCRIPTION

The operator panel (Figure 4) provides an integralconvenient means of checking or changing settings,and of checking relay-unit operations after a fault.Fault location, trip type, phase units which operated,and breakers which tripped are available for mostrecent 2 faults by using pushbuttons to step throughthe information. Targets from the last 16 faults arestored even if the relay is deenergized and are avail-able through remote communication only.

The operator panel contains 7 LEDs as follows:

(1) Relay in service — When this LED illuminatesthe MDAR (REL-300) relay is in service, thereis dc power to the relay and the relay haspassed the self-check and self-test. The LEDwill turned OFF if the relay has any internal fail-ure shown in the “Test” mode, and the relay tripoutput will be blocked.

(2) Settings — For read or change settings.

(3) Monitoring — The display shows three-phasevoltage, current and angle.

(4) Last Fault — When flashing, indicates new faultinformation available.

(5) Previous Fault — When last fault LED flashestwice per minute, indicates information for thefault proceeding the last fault.

(6) Value Accepted — When the “Settings” LED isalso ON, the “Value Accepted” LED flashesonly once, to indicate that a new setting valueis accepted; when the “Test” LED is also ON,the output contacts can be tested.

(7) Test — Use for verifying self-check and performfunctional test.The operator is notified that targets are avail-able by flashing LED's on the panel, plus anoutput relay contact provided to operate anexternal annunciator.

The operator can also look at non-fault voltage, cur-rent and phase angle on the display. Settings can beeasily checked as well. The display will be blockedmomentarily, every minute, for the purpose of self-check; this will not affect the relay protection function.

There are five test points on the MDAR (REL-300)relay front panel to measure power supply voltage.The test points provide measurement of the -24, +5, -12 and +12 Vdc voltages.

The serial port on the rear panel (Figure 2) is pro-vided for remote transmission of target data, remotesetting and optional oscillographic data. It also canbe used for future networking, data communications.

7.2 FRONT PANEL INTERFACE OPERATION

The operator interface consists of a vacuum displaywith four alphanumeric characters for the functionfield and four alphanumeric characters for the valuefield, seven pushbuttons, seven LED's, and five testpoints. All relay functions can be locally set, moni-tored, and tested from this front panel interface (Fig-ure 4).

7.2.1 Display Selection

The display selection pushbutton controls the type ofinformation displayed. The options include settings,metered values, two sets of fault data, and test mode.One of the five display modes is always selected andis indicated by an illuminated LED. Depressing the“DISPLAY SELECT” pushbutton changes the displayinformation to the next selection.

7.2.2 Entering Settings

The operation of the MDAR (REL-300) relay is con-trolled through the settings. To access the settings,the “DISPLAY SELECT” pushbutton should bedepressed until the “SETTINGS” LED is illuminated.The RAISE and LOWER FUNCTION pushbuttonsare depressed to scroll through the settings. TheRAISE and LOWER VALUE pushbuttons aredepressed to change the settings. When the desiredvalue appears on the VALUE display, depressing the“ENTER” pushbutton causes the displayed value tobe entered for the displayed function. The “VALUEACCEPTED” LED flashes once to indicate that thevalue has been successfully entered into the system.

7.2.3 Displaying Monitoring Data

All three-phase currents, voltages and phase anglesare available for on-line display during normal opera-tion. Conditions such as out-of-step blocking, loss-of-

Section 7. OPERATOR INTERFACE

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potential, and loss-of-current can also be monitored.Select the “VOLT/AMPS/ANGLE” function using the“DISPLAY SELECT” pushbutton. Scroll through themetered data using the RAISE and LOWER FUNC-TION pushbuttons. Upon initialization the display isset to show the IA current.

The phase rotation ABC or ACB is also displayed onthe monitoring mode depends on the setting of thejumper JMP3 on processor module. This feature isnot included in Version 2.6x.

7.2.4 Displaying Fault Records

The last two sets of fault data are available for dis-play. “LAST FAULT” is the data associated with themost recent trip event. “PREVIOUS FAULT” is thedata from the prior trip event. Select the desired setof target data using the “DISPLAY SELECT” push-button. Scroll through the fault data using the RAISEand LOWER FUNCTION pushbuttons. (Refer toChapter XI for more detail)

7.2.5 Display Test Mode Functions

The test display mode provides diagnostic and test-

ing capabilities for MDAR (REL-300). Information ofrelay status, A/D calibration, testing of the carriersend and receive functions for the pilot systems, andtrip relay test are among the functions provided. Toaccess the test function, the “DISPLAY SELECT”pushbutton should be depressed until the “TEST”LED is illuminated. The RAISE and LOWER FUNC-TION pushbuttons are depressed to scroll throughthe desired function. The required information willdisplay in the VALUE field. Contact output test canonly be performed when jumper JMP5 on the micro-processor module is in. (Refer to chapter VIII. Self-checking and Functional test” for more detail informa-tion).

7.2.6 16 Fault Records and IntermediateTargets.


7.2.7 16 Oscillographic Records


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7.3 DISPLAY AND TARGET INFORMATION

(1) Settings Display The setting display shows the followinginformation: Display

Information / Settings Function ValueField Field

Software version VERS 2.60

*Initiate OSC storage OSC TRIP/Z2TR/Z2Z3/DVDI

Initiate fault data storage FDAT TRIP/Z2TR/Z2Z3

CT ratio CTR 30-5000, (5)

PT ratio VTR 100-7000, (5)

Rated Freq. FREQ 60, 50

CT secondary rating CTYP 5 or 1

Enable/disable readouts in primary I & V values RP YES/NO

Positive line Reactance (:/unit distance)multiplier for fault locator XPUD 0.300-1.5, in 0.001/DTYP

Fault location, displayedin Km. or miles DTYP KM or MI (miles)

Reclosing mode:TTYP1)3PT on all faults, no RI. OFF2)3PT on all faults, 1PR

with 3RI on DG fault.3)3PT on all faults, 2PR

with 3RI on DG/2D fault.4)3PT on all faults w/3RI. 3PR5)SPT on DG fault w/SRI,

3PT on MD fault w/o RI. SPR6)SPT on DG fault w/SRI,

3PT on MD fault w/3RI. SR3R

@*Single phasing limit timer 62T 0.300-5.000 in 0.05 sec. steps

*Timer for pole-disagreement SPTT 1.000-6.000 in 1.0 sec. steps




RB on BF squelch BFRB YES/NO

Remote pilot control PLT YES/NO

Pilot system selection: STYP1) 3-zone non pilot schemes 3ZNP2) Zone-1 extension scheme Z1E3) POTT or Unblocking scheme POTT4) PUTT scheme PUTT5) Blocking scheme BLK

FDOG trip delay timer FDGT 0-15, in 1 cycle steps

Blocking system channel coordination timer BLKT 0-98, in 2 ms steps

Pilot phase unit PLTP #0.01-50.00, 0.01 ohm steps

Pilot ground unit PLTG #0.01-50.00, 0.01 ohm steps

Zone-1 phase unit Z1P #0.01-50.00, 0.01 ohm steps

Zone-1 ground unit Z1G #0.01-50.00, 0.01 ohm steps

Zone-1 delay trip T1 0-15, in 1 cycle steps

* Optional@ 62T will not be available if JMP2 is not on 2-3 position

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DisplayInformation/Settings Function Value

Field Field (note 1)

Zone-2 phase unit Z2P # 0.01-50.00, 0.01 ohm stepsZone-2 phase timer T2P 0.10-2.99,BLK,0.01sec.stepsZone-2 ground unit Z2G # 0.01-50.00, 0.01 ohm stepsZone-2 ground timer T 2G 0.10-2.99,BLK,0.01sec.steps

Zone-3 phase unit Z3P # 0.01-50.00, 0.01 ohm stepsZone-3 phase timer T3P 0.10-9.99,BLK,0.01sec.stepsZone-3 ground unit Z3G # 0.01-50.00, 0.01 ohm stepsZone-3 ground timer T3G 0.10-9.99,BLK,0.01sec.stepsZone-3 direction Z3FR FWD/REV

Z1L impedance angle PANG 40-90, in 1.0 degree stepsZOL impedance angle GANG 4 0-90, in 1.0 degree stepsZOL/Z1L ZR 0.1-7.0, in 0.1 steps

Low voltage units LV 4 0-60, in 1.0 volt steps.Low set phase o/c unit IL 0.5-10, in 0.1 amp stepsMed set phase o/c unit IM 0.5-10, in 0.1 amp stepsLow set ground o/c unit IOS 0.5-10, in 0.1 amp stepsMed set ground o/c unit IOM 0.5-10, in 0.1 amp stepsHigh set phase o/c unit ITP # 2.0-150.0, 0.5 amp stepsHigh set ground o/c unit ITG # 2.0-150,0, 0.5 amp steps

Out-of-step block zone-1 OSB1 YES/NOOut-of-step block zone-2 OSB2 YES/NOOut-of-step block pilot OSBP YES/NOOS & OS override timers OSTM 500, 1000 msOSB inner blinder RT 1.00-15.00, 0.1 ohm stepsOSB outer blinder RU 3.00-15.00, 0.1 ohm steps

Directional ground units DIRU ZSEQ, NSEQ, DUALGround backup time curves GBCV # CO-2, CO-5, CO-6, CO-7,

CO-8, CO-9 and CO-11.Ground backup setting GBPU 0.5-4.0, in 0.1 amp stepsGround backup time dial GTC 1-63, in 1.0 stepsChoice of directional or non-directional ground backup GDIR YES/NO

CIF trip CIF YES/NO

LLT trip LLT YES/FDOG/NO

LOP block LOPB YES/NO

LOI block LOIB YES/NO

Trip alarm seal-in AL2S YES/NO

Remote setting SETR YES/NO

Real time clock TIME YES/NO1) set year YEAR 1980-2079,in 1 year steps2) set month MNTH 1-12, in 1 month steps3) set day DAY 1-31, in 1 day steps4) set week day WDAY SUN/MON/TUES/WEN/

THUR/FRI/SAT5) set hour HOUR 1-24, in 1 hour steps6) set minute MIN 1-60, in 1 minute steps

* Optional, # use “OUT” for disabling this unit.

Note: When the CTYP is set at 1 ampere, the range of the following functions is as shown below:

Z1P/Z1G/Z2P/Z2G/Z3P/Z3Gand PLTP/PLTG 0.05-250.00, in 0.05 ohms stepsITP/ITG 0.4-30.0, in 0.1 amp. steps

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(2) Monitoring DisplayThe metering group display shows the following information.


Field Field (note)

Phase A current (mag.) IA numerical, A“ (ang.) ∠IA deg.

Phase A voltage (mag.) VAG numerical, v“ (ang.) ∠VAG deg.

Phase B current (mag.) IB“ (ang.) ∠IB

Phase B voltage (mag.) VBG“ (deg.) ∠VBG

Phase C current (mag.) IC“ (ang.) ∠IC

Phase C voltage (mag.) VCG“ (ang.) ∠VCG

Date DATE XX.XX (month.day)Time TIME XX.XX (hour.minute)Local/Remote Setting SET LOC/REM/BOTHCarrier Receiver-1 RX-1 YES/NOLOP Indication LOP YES/NOLOI indication LOI YES/NOOut-of-step block OSB YES/NO

* Optional

Note: All displayed phase angles are referred to V A as reference.

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(3) Fault Data Display

The MDAR (REL-300) saves the latest 16 fault records, but only the latest two fault records can beaccessed from the front panel. For complete 16 fault records, one of the communication interfacedevices are required.

Each set of fault target record display shows the following information:

Display

Information Function ValueField Field

Fault occurred at:1.date DATE XX.XX (month.day)2.year YEAR XXXX3.time TIME XX.XX (hour.minute)4.second SEC XX.XX (second)

Fault type FTYP AG/BG/CG/AB/BC/CAABG/BCG/CAG/ABC




Zone-2 phase tripped Z2P “Zone-2 ground tripped Z2G “


Pilot phase tripped PLTP “Pilot ground tripped PLTG “

High set phase tripped ITP “High set ground tripped ITG “

Close-into fault trip CIF “

Load-loss tripped LLT “

Ground backup tripped GB “

*Sec. fault tripped(SPF) SPF “*62T tripped 62T “

* Optional functions for single-pole trip.

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Field Field (note)

Fault location Z In ohmsFault Z angle FANG numericalFault distance DMI or DKM In miles or KM

Prefault load current PFLC numerical, APrefault phase voltage PFLV numerical, VPrefault load angle LP numerical, deg.

Carrier send SEND numerical,RCVR #1 RX1 numerical,Fault voltage VA (mag.) VPA numerical, V(ang.) ∠ VPA numerical, deg.

Fault voltage VB (mag.) VPB numerical, V(ang.) ∠VPB numerical, deg.

Fault voltage VC (mag.) VPC numerical, V(ang.) ∠VPC numerical, deg.

Fault voltage 3VO(mag.) 3VO numerical, V(ang.) ∠3VO numerical, deg.

Fault current IA (mag.) IPA numerical, A(deg.) ∠IPA numerical, deg.

Fault current IB (mag.) IPB numerical, A(deg.) ∠IPB numerical, deg.

Fault current IC (mag.) IPC numerical, A(deg.) ∠IPC numerical, deg.

Fault current 3I0(mag.) 3IO numerical, A(deg.) ∠3IO numerical, deg.

Pol. current IP (mag.) IP numerical, A(deg.) ∠IP numerical, deg.

* Optional

Note: All displayed phase angles are referred to VA as reference.

Note: The “Relay In Service” LED indicates the MDAR (REL-300)ms system is in-service. It will come onwhen the dc is applied and after the system is initialized.

(4) Test Functions Display

Five functions are available in the test function mode. They are: STAT, ADC, RS1, TK and TRIP.

STAT The STAT is the relay self-check status. MDAR (REL-300) jumps to the test mode status display(STAT) to show the cause of the problem. A zero value indicates that no self-check failure hasoccurred. A nonzero hex byte form value indicates hardware or software failed. Refer to ChapterVIII for more detail.

ADC The ADC value display is for use in calibration of the analog input to MDAR (REL-300) and is onlyvisible when MDAR (REL-300) is in calibration mode (JMP6 on processor module installed). Referto Appendix E for calibration.

RS1, TK and TRIP

These selections are for functional tests. When the selector is in the test mode,

scroll the function field by the raise pushbutton. The value field display showsRS1, (Carrier receiver #1), and TK (Carrier send). Refer to Chapter VIII for moredetailed information.

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If jumper JMP5 on the processor module is set to IN position, the following tencontacts can be selected for testing. Refer to Chapter VIII for more detailedinformation.

TRIP RELYBFI RELYRI1 RELYRI2 RELYRB RELYAL1 RELYAL2 RELYGS RELYSEND RELYSTOP RELY

7.4 16 FAULT RECORDS AND INTERMEDIATE TARGETS.


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9.1 LOSS-OF-POTENTIAL SUPERVISION (LOP)

The ac voltage monitoring circuit is called loss-of-potential circuit.

In order to prevent undesirable tripping due to thedistance unit(s) pickup on loss-of-potential, logic (lowvoltage and not VI) and (Vo and not Io) are includedin MDAR (REL-300) design, as shown in Figure 12A.The low voltage and Vo units for the LOP logic areset at a fixed value of 7 volts. Under loss-of-potentialcondition, low voltage (or Vo) and not VI (or Io) satisfyAND-1. The output signal of AND-1 starts the 8/500ms timer. The timer output will satisfy AND-1C ifthere is no output from AND-1B. The output signal ofAND-1C will block all the distance unit tripping pathsvia AND-2, AND-3, AND-4, AND-5, AND-6, AND-172(also blocks AND-191 and AND-187 for pilot sys-tems) if LOPB is set to “YES”. The LOPB blockingfunction can be disabled by selecting the LOPB valuedisplay to NO.

The output of the LOP timer will turn on the non-memory LOP indicator on the metering display dur-ing the LOP condition via AND-1F after 500 msdelay. This output is also connected to the failurealarm output relay GS (Alarm-3).

In selecting the LOPB to “YES”, the intent is to blockall the distance units from tripping should a LOP con-dition exist. However, for a condition as shown in Fig-ure 12B, a single-end source energizes two parallelcircuits without pre-fault load current. The MDAR(REL-300) at the remote end B of the protected linemay fail to trip for an internal fault near the source-end A, because its LOP sets up before the terminal Atrips. This is because the relay at B sees no current,but sees a low voltage condition before circuitbreaker A opens.

Also, for a condition as shown in Figure 12C, anevolving fault at 50% location with symmetricalsource impedances, MDAR (REL-300)'s at both Aand B will not trip if LOPB is selected to “YES”,because neither MDAR (REL-300) sees a currentchange (or no Io) on the protected line to set up theLOPB logic before the second fault is applied.

Logic AND-1A,-1B,-1C,-1E and OR-1D, and 150/0, 0/3500 ms timer circuits in Figure 12A are for solvingthese problems. This logic unblocks the LOPB circuitand provides a 3500 ms trip window for the distanceunits to trip if the fault current is detected within 150ms after LOP has been set up. The 150 ms timer canbe extended to 500 ms if a jumper (JMP3) on theMicroprocessor module is installed.

9.2 MONITORING OF AC CURRENT (LOI)

The ac current monitoring circuit is similar to the LOPlogic, except using IOM and not Vo as a criterion, asshown in Figure 13. Under a ct short circuit or opencircuit condition, IOM and not Vo satisfies AND-23.The LOI output signal from AND-23 starts the 500/500 ms timer. The output of the timer will turn on thenon-memory LOI indicator on the metering displayduring the LOI condition. This output is also con-nected to the failure alarm output relay GS (AL-3).The LOI signal also can be used to block the MDAR(REL-300) trip outputs under LOI condition if theLOIB (loss-of-current block) is selected to YES.

9.3 OVERCURRENT SUPERVISION(Figure 14)

The MDAR (REL-300) distance units do not requireovercurrent supervision, because the relay normallyoperates in a background mode. They will not startthe zone-1 and pilot impedance computation until aphase current or a phase voltage disturbance isdetected. This approach can minimize the load prob-lem on setting the phase overcurrent units. However,in order to meet the traditional practice, a medium setphase overcurrent unit IM (IAM or IBM or ICM) hasbeen added to MDAR (REL-300) versions 2.10/2.60to supervise Z1P/Z2P/Z3P/PLTP trip functions, asshown in Figure 14. This unit should not be set tolimit the zone-3 reach, and traditionally should be setabove the load current.

For increasing the security, the application of LOPBsupervision function is still normally recommended.

For coordination purposes, the ground trip units Z1G,Z2G, Z3G, PLTG, and FDOG are supervised by themedium set ground overcurrent unit IOM, except theZ3G/RDOG units (for carrier start on blockingscheme, and for reverse blocking on permissivescheme) are supervised by the low set IOS. The Iom

Section 9. OPERATION OF MDAR (REL 300) BASIC FUNCTIONS

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and Ios settings must be coordinated with oneanother.

Besides the above supervisions, the MDAR (REL-300) is supervised by a different kind of faulted phaseselector signal on each trip path. The faulted phaseselector uses current only(I1 + I2) approach. For ØØ - unit tripping there mustbe I2 present.

9.4 ZONE-1 TRIP

When the MDAR (REL-300) functional display“STYP” is selected to “3ZNP” it will perform 3-zonenon-pilot functions.

For Zone-1 phase faults, the Z1P unit will see thefault and operate. As shown in Figure 15. Outputs ofZ1P, IM plus the operation of FDOP, if applied, satis-fies AND-2 and provides a high speed trip (HST) sig-nal from OR-2 to operate the trip output telephonerelay. The trip circuit is monitored by a seal-in reedrelay S, which is in series with each trip contact in thetripping circuits. The S relay will pick up if the trip cur-rent is higher than 0.5 amp. The operation of theseal-in contact “S” (i.e. after breaker trip coil hasbeen energized) provides the trip seal-in signalTRSL. It feeds back to OR-4 and AND-8 to hold thetrip relay in operation until the breaker trips and the52b contact opens (not shown in Figure 15). The tripcontact and the TRSL signal can be delayed dropoutby 50ms after the trip current is removed, providingJMP4 on the microprocessor board is connected.The TRSL signal from AND-8 plus the output signalfrom AND-2 turn on the Zone-1 phase trip indicatorZ1P. The breaker trip and Zone-1 phase trip indica-tors are sealed-in. They can be reset only after man-ually pushing the RESET pushbutton on the frontpanel, or through remote communication. The flash-ing LED will be reset, but the fault information will stillremain in memory.

The Z1P 3ø trip logic AND-131 is also supervised bythe selectable OSB logic when the OSB1 is selectedto “YES”.

Z1P logic AND-2 is also supervised by the FDOP(forward directional overcurrent phase unit) when theOSB1 or OSB2 or OSBP is selected to “YES” formore security on some special power system appli-cations (Refer to Chapter XI, paragraph G for a moredetailed explanation).

Similar operations function for Zone-1 single-phase-to-ground faults. The Z1G unit sees the fault and

operates along with the IOM and FDOG units, satisfy-ing AND-3. Tripping is initiated via OR-2 with Zone-1ground trip Z1G indication. Logic AND-3 is alsosupervised by the signal of RDOG (reverse direc-tional overcurrent ground) for security.

A two-out-of-three “leading phase blocking” logic isincluded for solving the overreach problem of the sin-gle-phase ground distance units which may respondto a ØØG fault.

The Z1G unit is also supervised by the signal ofunequal-pole- closing.

The T1 timer, as shown in Figure 15, provides timedelay on Z1P/Z1G trip if required. The range of T1timer is 0 to 15 cycles in 1.0 cycle steps. Normally,the T1 timer should be selected to zero time delay,unless it is needed. For example, when using MDAR(REL-300) as a non-pilot 3PT backup with anothersystem operated on SPT mode, set MDAR (REL-300) Zone-1 with delay.

HST signal also is connected to the reclosing initia-tion logic.

Either or both Zone-1 phase and Zone-1 groundfunction(s) can be disabled by selecting the Z1P and/or Z1G to OUT.

9.5 ZONE-2 TRIP

For Zone-2 phase faults, the Z2P unit will see thefaults, plus the output of IM, operates the Zone-2phase timer T2P. Z2P output plus the T2P timer out-put satisfy AND-4 as shown in Figure 16. AND-4 out-put provides time delay trip signal TDT via OR-3.Signal TDT picks up OR-4 (Figure 15) and operatesthe trip relay. The tripping and targeting are similar asdescribed in Zone-1 trip except with Zone-2 phasetime delay trip Z2P indication.

Similar operation occurs for Zone-2 single-phase-to-ground faults. The Z2G unit sees the fault and oper-ates. This plus the operation of the IOM, FDOG andT2G, satisfies AND-5, and provides the TDT signalvia OR-3 with Zone-2 ground time delay trip indicatorZ2G.

Zone-2 3ø unit is supervised by the selectableOSB2.

The single phase ground distance units may respondto a ØØG fault. The output of the Z2G unit plus theoperation of the ØØ - selection will trip the Z2P viaOR-157, T2P and AND-18. Leading phase blockingis unnecessary for an overreach zone device.

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TDT signal can be connected to the reclosing blocklogic.

Either or both Zone-2 phase and Zone-2 groundfunction(s) can be disabled by selecting the Z2P and/or Z2G to OUT; or can be disabled by selecting theT2P and/or T2G to BLK.

9.6 ZONE-2 TRIP

For Zone-3 phase faults, the Z3P unit (forward orreverse looking, depending on the Z3FR set to FWDor REV) will see the faults and operate the Zone-3phase timer T3P. The Z3P output plus the T3P timeroutput satisfy AND-6 as shown in Figure 17. AND-6output provides time delay trip signal TDT via OR-3.Signal TDT picks up OR-4 (Figure 15) and operatesthe trip relay. The tripping and targeting are similar toZone-1 trip, except with zone-3 phase time delay tripZ3P indication.

Zone-3 3ø unit is not supervised by the OSB logic.

For Zone-3 single-phase-to-ground faults, the Z3Gsees the fault and operates. This plus the operationof the IOM, satisfy AND-7. This provides the TDT sig-nal, then trips via OR-3 with zone-3 ground timedelay trip indicator Z3G. TDT signal can be con-nected to the reclosing block logic. For security, theZ3G unit is also supervised by the signal of RDOGwhen it is set for reverse looking (or by the signal ofFDOG when it is set for forward looking) via logicOR-171B and AND-171A as shown in Figure 17.

Either or both Zone-3 phase and Zone-3 groundfunction(s) can be disabled by selecting the Z3P and/or Z3G to OUT; or by selecting the T3P and/or T3Gto BLK.

9.7 DIRECTIONAL INSTANTANEOUSOVERCURRENT TRIPS

The directional instantaneous overcurrent units IAH,IBH, ICH and IOH are supervised by the FDOP (A, Band C) for phases and by FDOG for ground. Theseunits are normally set high to detect those faultswhich occur in the Zone-1 area. Therefore, their trip-ping will occur via OR-2 for HST, as shown in Figure18. The use of directional supervision will minimizesome setting difficulties in applications. The setting ofLOPB has no effect to the high-set trip functionexcept the units will become a non-directional duringLOP condition if the LOPB setting is set to YES.These high-set trip functions can be disabled by set-ting the ITP (phase) and/or ITG (ground) to OUT.

9.8 CLOSE-INTO-FAULT TRIP

In order to supplement distance unit operation whenthe circuit breaker is closed into a fault and line sidepotential is used. The CIF close-into-fault trip circuit,as shown in Figure 19, includes logic AND-22, OR-3and 100/180 ms and 16/0 ms timers. Logic AND-22is satisfied and produces a trip signal for 180 ms aftercircuit breaker closing (52b contact opened) if theovercurrent unit(s), IAL, IBL, ICL or IOM, operate OR-11, and if any phase voltage is below the preset levelof the LV-units (OR-222A). Tripping will be via OR-3,with RB and CIF target.

The application of the “close-into-fault” function isselected by the setting of the CIF to YES.

9.9 UNEQUAL-POLE CLOSING LOAD PICKUPCONTROL

The ground units may pick up on a condition of loadpickup with unequal breaker pole closing. The highspeed trip ground units Z1G and FDOG/IOM shouldbe supervised under this condition. This can beachieved, as shown in Figure 20, by inserting a 0/50ms timer and controlling by the 52b signal to super-vise the Z1G trip path AND-3 (Figure 15) and FDOG/IOM trip path AND-188 (Figures 26 and 34). It shouldbe noted that the 50 ms time delay will have no effecton a normal fault clearing.

The ground distance unit PLTG is less sensitive asthe FDOG, it is not need to have this supervising cir-cuit.

On internal ground faults, if the mechanical actuatorof the circuit breaker operates, but the arc does notextinguish (e.g. due to low gas pressure), the closingaction of the 52b contact, connected to MDAR (REL-300), will reset the Z1G trip path AND-3, and ulti-mately, the BFI contact. This may introduce interrup-tion to the BF scheme if BFI logic does not provideseal-in circuit. The AND-3C logic in Figure 20 willsolve this problem.

9.10 INVERSE TIME DIRECTIONAL OR NON-DIRECTIONAL OVERCURRENT GROUNDBACKUP (GB)

The overcurrent ground backup unit GB is to supple-ment the distance ground protection on high resis-tance ground faults. Its selectable time characteristiccurves, as shown below, are similar to the conven-tional CO relays.

CO-2 Short time curve

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Curve No. T0 K C P R

CO2 111.99 735.00 0.675 1 501C05 8196.67 13768.94 1.130 1 22705CO6 784.52 671.01 1.190 1 1475CO7 524.84 3120.56 0.800 1 2491CO8 477.84 4122.08 1.270 1 9200CO9 310.01 2756.06 1.350 1 9342CO11 110.00 17640.00 0.500 2 8875

CO-5 Long time curveCO-6 Definite time curveCO-7 Moderately inverse time curveCO-8 Inverse time curveCO-9 Very inverse time curveCO-11 Extremely inverse time curve

As shown in the setting table, the time curve can beselected by using the “GBCV” setting, the time dial isset by the “GTC” value. The following equation canbe used to calculate the trip time for all CO curvesfrom CO-2 to CO-11:

GBPU = Pickup current setting (0.5 to 4.0A)GTC = Time curve dial setting (1 to 63)T0, K, C, P and R are constants, and are shown asbelow:

The GB function can be set as either directional ornon-directional by setting the “GDIR” to YES or NO.

T sec( ) T 0K

3I0 C–( )P---------------------------+GTC24000---------------for 3I0> 1.5= =

T (sec)R

3I0 1–( )---------------------GTC24000--------------- for 1 3I0 1.5<<=

where 3I0

IFGBPU------------------=

set to DUAL position. However, the GB-unit will becontrolled by the negative sequence voltage and cur-rent polarized element if the value field is selected toNSEQ (negative sequence). The pickup value of theovercurrent unit is controlled by the “GBPU” setting.The unit can be disabled by selecting the “GBCV” toOUT.

9.11 ZONE-1 EXTENSION

This scheme provides a higher speed operation onend zone faults without the application of pilot chan-nel.

If the MDAR (REL-300) functional display “STYP” isselected to Z1E, the Z1P/Z1G unit will provide twooutputs. One is overreach (reach to 1.25 times thezone-1 setting) and one is the normal zone-1 reach.A single shot instantaneous reclosing device shouldbe used when applying this scheme. The targetsZ1P/Z1G will indicate either zone-1 trip and/or Z1Etrip operations. The other functions, such as Z2T,Z3T, ac trouble monitoring, overcurrent supervision,IT, CIF, unequal-pole closing load pickup control,load-loss acceleration trip, etc. would remain thesame as in the basic scheme (3ZNP).

For a remote internal fault, (Figure 22), either Z1P orZ1G will see the fault since they overreach to

The directional GB function uses the torque controlapproach as indicated in Figure 21. The directionalelement can be selected with either zero sequenceor negative sequence as a polarizing quantity,depending on the application. By scrolling the func-tional field to DIRU (directional unit) and selectingZSEQ in the value field, the GB-unit will be controlledby the zero sequence voltage polarized element. TheGB-unit will be controlled by either the zerosequence voltage 3Vo polarized element and/or thezero sequence current IP polarized element (currentfrom a power transformer neutral CT) if the DIRU is

1.25(Z1P/Z1G), high speed tripwill be performed via the normalZ1T path (Figure 15) AND-2 (orAND-3) and OR-2. HST signaloperates the instantaneousreclosing scheme. The breakerrecloses and stays closed if thefault is automatically cleared.

Target Z1P and/or Z1G will be dis-played. Once the breaker trip cir-cuit carries current, it operates the

logic OR-5 (not shown), produces output signalTRSL, and satisfies logic AND-26 for 5000 ms (Fig-ure 25). The output signal of AND-26 will trigger theZ1P/Z1G reach circuit, constricting their reachesback to the normal Zone-1 for 5000 ms. During thereach constricting periods, if the breaker is reclosedon a Zone-1 permanent fault, it will trip again. If thebreaker is reclosed on an end-zone permanent fault,the normal Z2T will take place.

For a remote external fault, either Z1P or Z1G will seethe fault since they are set to overreach. High speed

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trip will be performed. HST signal operates theinstantaneous reclosing scheme. The breakerrecloses and stays closed if the fault has been iso-lated by the adjacent line breaker.

However, if the adjacent line breaker fails to trip, thenormal remote back up will operate.

9.12 SELECTABLE LOSS-OF-LOADACCELERATED TRIP (LLT)

The load loss accelerated Zone-2 trip logic sensesremote 3-pole clearing on all faults except 3Ø tocomplement or substitute for the action of the pilotchannel, speeding up trip at the slow terminal. Thelogic includes AND-24, AND-25, OR-13, 0/32 and the10/0 ms timers, as shown in Figure 23. Under normalsystem conditions, 3-phase load currents are bal-anced, and the low set overcurrent units IAL, IBL, ICLsatisfy both AND-24 and OR-13. On internal endzone faults, Z2P, Z2G and/or FDOG/IoM picks up andsatisfies the third input to AND-25 via OR-6. How-ever, the signal from AND-24 is negated to AND-25,therefore, AND-25 should have no output until theremote end 3-pole trips.

At this time the local end current will lose one or twophases, depending on the type of fault (except 3-phases), and AND-24 output signal changes from “1”to “0”, satisfying AND-25. After 10 ms this outputbypasses T2 timer and provides speedup Zone-2trip. The 10/0 ms time delay is for coordination onexternal faults with unequal pole clearing. The 0/32ms timer is needed for security on external faults withno load current condition. Targets LLT will turn onafter an LLT trip.

The LLT function is selected by the setting of “YES,FDOG, NO”, where YES = LLT with Z2 supervision;FDOG = LLT with both Z2 and (FDOG/IOM) supervi-sion; and NO = LLT function is not used.

LLT is not recommended for 3-terminal line applica-tion due to difficulty in determining proper setting ofIL and complicated infeed from the third terminal.

9.13 PROGRAMMABLE RECLOSING INITIATION(Figure 24)

The MDAR (REL-300) system provides the followingcontact output for reclose initiation (RI) and recloseblock (RB) functions:

RI1, used for reclose initiation on single pole trip.RI2, used for reclose initiation on 3-pole trip.RB, used for reclose block.

The operation of RI1, RI2 and RB contacts is con-trolled by the setting of the programmable reclose ini-tiation logic as shown in Figure 24. The operation ofeither RI1, RI2 or RB must be confirmed by the signalof TRSL, which is the trip output of MDAR (REL-300)operation.

The External Pilot Enable Switch (refer to Figure 6,terminals 9 and 10 on TB-5), is used for externallyenabling the pilot system.

The PLT setting is similar to the external pilot enableswitch, except it is set from the front panel (orremotely set via the communication interface).

For pilot MDAR (REL-300) with supporting non-pilotfunction, a most popular reclose initiation practice isto have reclosing initiation on high speed trip (pilot,Zone-1 and high set) only. Referring to Figure 24, thiscan be programmed by closing the external pilotenable switch and selecting PLT and Z1RI to YES.AND-84 will produce logic to operate the RI2 relaywhen receiving signals from TRSL and AND-89. Theuse of Z1RI signal to supervise the AND-84 providesa flexibility for disabling RI, if needed, when pilot is in-service. The program is further controlled by theTTYP setting.

TTYP set at OFF — 3PRN provides no output,therefore, RI2 will not operate.

TTYP set at 1PR — 3PRN will provide output “1”on ØG faults only (via OR-100 andAND-51A), RI2 will operate.

TTYP set at 2PR — 3PRN will provide output “1”on ØG fault or ØØ faults (via OR-100B and AND-51B), RI2 willoperate.

TTYP set at 3PR — 3PRN will provide output “1”on any type of fault (via OR-51),and RI2 will operate.

The Z1RI, Z2RI AND Z3RI settings combining withthe logic of AND-62B, -62C, -62D and OR-62 providefor programming applications where the reclose initi-ation on Zone-1, Zone-2 or Zone-3 trip is desired ona non-pilot MDAR (REL-300) system. AND-62A iscontrolled by the signal 3PRN, therefore, the settingof 1PR, 2PR and 3PR also affects the Z1RI, Z2RIand Z3RI program.

In general, the RB relay will operate on TDT (timedelay trips) or OSB (out-of-step block condition).However, it will be disabled by the setting of Z1RI,

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Z2RI or Z3RI signal via OR-62 and AND-86.

9.13.1 Logic for RB on BF squelch

For a pilot system, the BFI signal can be used to stop(for a blocking system) or start (for permissiveschemes) the carrier channel to allow far end line ter-minals to trip in the event a breaker close to an exter-nal fault fail to open. The problem is how to inhibit itreclosing on those terminals, to limit damage.

MDAR (REL-300) solves this problem at the far endterminals by the Reclose Block on Breaker FailureSquelch logic in the RI/RB software. When thebreaker fails to trip, the BFI logic squelches the chan-nel to continuous permissive signal, or stops theblocking signal. This is done after some time delay.The relay at the far end, having sensed the externalfault in the forward direction, sees the permissive sig-nal (or stoppage of blocking signal) much later than itwould for a normal pilot trip operation initiated byrelay forward-looking elements at the end closer tothe fault. This time delay is used to differentiatebetween a faster normal pilot trip and the slowerproblem-related pilot trip initiated by BFI, and to blockreclosing in the later case.

This logic is shown in Figure 24, which includes theAND-61A and a 132/0 ms timer. The logic at the farend terminal will initiate RB and inhibit RI) at 132 ms(about 8 cycles) after the fault is detected by theoverreaching PLTP or PLTG element, if the pilot isenabled and the TRSL signal is received on anythree-pole trip operation. If the fault is cleared beforethe 132 ms expiration of the timer, normal reclosingwill occur.

9.13.2 For Single-pole-trip and pilot applications

The RI1 relay is provided for single-pole trip scheme,which is controlled by the TTYP setting of SPR andSR3R. Refer to Chapter X, Operation of MDAR(REL-300) Optional Functions for the programmablereclose initiation on single-pole trip or pilot applica-tions.

9.14 POWER SWING BLOCK SUPERVISION,OSB

The Out-of-step blocking (OSB) logic in MDAR (REL-300) is a dual blinder scheme. It contains two blinderunits, providing 4 blinder lines. The nature of the logicshown in Figure 25 is that the outer blinder 21BOmust operate 50 ms or more ahead of the innerblinder 21BI, in order for an OS condition to be identi-fied.

The OS logic is also supervised by the medium setphase overcurrent signal (AND-122 on Figure 25).The OSB signal is a negated input to the AND-131(Z1P), AND-147 (Z2P), and AND-176 (PLTP) forsupervising the 3-phase distance trip.

The OSB signal is also applied to the reclosing logicfor initiating RB.

The OSB logic as shown in Figure 25 is proposed byEPRI/China. Its design is based on the power systemoperation practices and experiences in China. Itincludes the following unique features:

• OSB is not applied to zone-3.

• OSB for zone-1, zone-2 and pilot is selected bythe setting of OSB1, OSB2 and OSBP,respectively.

• Use separated timers OSOT1 and OSOT2 inzone-1 and zone-2 logic for out-of-step overridetripping, as shown in Figure 25.

• An selectable OSTM timer setting, range 500 or1000 ms, is provided for the logic. This timer willbe used for the following features.

• In order to ensure continuously OS block to theZ-units from tripping on the second and thefollowing OS cycles where the swing rate may befaster than the previous cycles, the modified OSlogic provides that once the out-of-step conditionis identified, the reset time of the output signalfrom the OS timer will be controlled by the presettime of OSTM.

• Provide logic for blocking zone-1 and pilot (notzone-2 and zone-3) 3-phase units on severeexternal fault with delay clearing (e.g. breakerfailure condition). This logic included the 21BIsignal, the 200/OSTM timer, and OR-122A, OR-201A, as shown in Figure 25.

9.15 Communications

Refer to chapter XI for detail.

9.16 Fault Records and Intermediate Targets

Sixteen records and targets are stored. Refer tochapter XI for detail.

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10.1 PILOT SCHEMES

If the MDAR (REL-300) with pilot optional functionand its functional display “STYP” is not selected to“3ZNP” or “Z1E”, it will perform one of the other threepilot schemes shown below, depending on the set-ting.

For activate the pilot logic, an external rated voltageshould be connected to the “Pilot Enable” terminals(Figure 6, TB5/9 and TB5/10), and the setting of PLTshould be set to YES.

Whether the pilot system is in-service or not, the 3-zone non-pilot function of the assembly is at a sup-porting backup mode.

STYPSetting Scheme

3ZNP Non-pilot 3-Zone distanceZ1E Zone-1 extensionPOTT Permissive overreach transfer

trip/unblockingPUTT Permissive underreach transfer tripBLK Blocking

10.1.1 Permissive overreach transfer trip/simpli-fied unblocking

If the functional display “STYP” is selected to POTT,the MDAR (REL-300) will perform either the POTTscheme or the Simplified Unblocking scheme,depending on the applied pilot channel.

The following IMPORTANT settings are recom-mended for POTT and Unblocking system:

OSC = Z2Z3FDAT = TRIPPLT = YESSTYP = POTTFDGT > 3 cyclesRBSW (blank)Z3FR = REV (must)

The basic operating principles of a POTT system are:

(a) The pilot relays, PLTP/PLTG, are set to over-reach the next bus.

(b) The pilot channel is a frequency shift typedevice. Its signal may be through either metallicwire or microwave.

(c) Transmitter frequency should be different ateach terminal. The channel is normally oper-ated on a guard frequency, and

(d) the channel frequency will be shifted fromguard to trip when the pilot relay(s) is operated,and

(e) pilot trip is performed when the pilot relay(s)operates and a pilot trip frequency signal fromthe remote end is received.

The basic operating principles of a simplifiedunblocking system are the same as the POTT sys-tem, except it is slightly different in application.

(a) The pilot channel is a frequent shift type powerline carrier. The transmitter frequency must bedifferent at each terminal. It is normally oper-ated on a blocking frequency and will be shiftedto an unblocking frequency when the pilotrelay(s) operates, and

(b) The carrier receiver should provide a logicwhich in the event of loss-of-channel or lowSNR ratio, the pilot trip circuit is automaticallylocked out after a short time delay. Pilot trip isprovided, however, if the tripping distancerelay(s) operates during this short time periodbetween loss-of-channel and pilot trip lockout.(W) type TCF-10B receiver provides this logic.It provides 150 ms trip window, then automati-cally locks out after loss-of-channel.

(c) The function of “indication for low signal andloss-of-channel” condition will not be providedon the MDAR (REL-300) simplified unblockingscheme. It would normally be incorporated inthe power line carrier equipment.

The operating principle of the pilot distance measure-ment units, PLTP/PLTG are the same as the non-pilotzone distance measurement units, and are super-vised by the same LOPB, OSB, FDOP, FDOG andIom units as shown in Figure 26.

For more dependability on high Rf faults, the pilotground PLTG trip logic is supplemented with theFDOG and IOM units, as shown in Figure 26. TheFDOG directional unit is determined by the setting ofDIRU to ZSEQ, NSEQ OR DUAL. The delay timer

Section 10. OPERATION OF MDAR (REL-300) VERSION 2.60PILOT AND OPTIONAL FUNCTIONS

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FDGT has a range of 0 to 15 cycles, in 1 cycle steps.It can be blocked by setting the FDGT to BLK.

The pilot distance unit PLTG is always active and hasthe priority for tripping, therefore, practically, theFDGT timer should be set to 3 cycles or longer forsecurity reason.

The pilot phase and/or pilot ground function(s) canbe disabled by selecting the PLTP and/or PLTG toOUT. (note, the FDOG pilot trip function will also bedisabled when PLTG set to OUT).

POTT and simplified unblocking system includes thefollowing three portions:

(a) Tripping logic (Figure 27)

(1) For a forward external fault, the local pilotPLTP and/or PLTG sees the fault, oper-ates and keys.

The output from OR-40 will satisfy thefirst input to the AND-30. Now, assumingthat TBM logic does not operate and PLTpilot enable is set, three out of fourinputs of AND-30 are satisfied, but pilottrip should not occur since the remotetransmitter still sends a guard (or block-ing) frequency signal.

(2) For an internal fault, the pilot relays atboth ends, PLTP and/or PLTG, see theinternal fault and operate. Together withreceived trip (or unblocking) frequencysignal CR via AND-44 in Figure 28, sat-isfy AND-30 in Figure 27. Pilot trip signalPT will be applied to OR-2 from AND-30.High speed pilot trip, HST, would beobtained. Targets of pilot phase trip,PLTP, and/or pilot ground trip, PLTG, willbe turned on after the breaker trips.

(b) Carrier Keying Logic (Figure 28)

(1) Forward fault keying

For a forward internal or external fault,the local pilot relay(s), PLTP and/orPLTG, sees the fault, picks up, and oper-ates OR-40, AND-45, OR-18 and AND-35 if PLT pilot enable is set, and if func-tional display “STYP” is selected toPOTT. The output signal from AND-35will operate the reed relay SEND, key thelocal transmitter and shift the transmit-ting frequency from a guard to a trip for

POTT scheme (or from a blocking to anunblocking for Unblocking scheme), toallow the remote pilot relay system totrip.

For security reasons, the keying circuit isdisabled by the time delay trip signalTDT (includes Z2T, Z3T, CIFT AND GB),which is not shown in Figure 28.

(2) Breaker open key logic — Echo keying(Figure 28)

Since the POTT and the simplifiedunblocking system require the receivingof a permissive signal from the remoteend for pilot trip, provision should bemade for covering the condition whenthe remote breaker is opened.

MDAR (REL-300) version 2.10 usesecho key approach (note, some olderversion use 52b key approach) forbreaker open key condition. When theremote breaker is opened, the remotebreaker echo key logic will echo the sig-nal back to the local terminal for permis-sive tripping. The echo key logic AND-34B, in Figure 28, will be satisfied if the52b contact is closed (breaker open),and neither forward pilot relay (OR-40)nor reverse looking relay (for reverseblock) has output, and there is outputfrom AND-44.

The echo key logic will operate the OR-18 and send carrier for 150 ms. The 8/0ms delay between AND-44 and AND-34B is required for overriding any noisefrom the channel.

(3) Signal Continuation Logic (Figure 28)

This logic includes the signal of TRSL, 0/150 ms timer, AND-34A, OR-18 andAND-35. The 0/150 ms signal continua-tion time is required to keep the localtransmitter at the trip frequency (orunblocking) for 150 ms immediately afterthe local breaker trip signal TRSL ispresent. This is required for sequentialtrip. This logic will be disabled by thetime delay trip signal TDT via 0/300 mstimer and AND-34A, i.e. the signalcontinuation logic will not be performedon any time delay trip operation. Also,

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the signal continuation will not be per-formed if the trip is caused by a CIFfunction (AND-49E and OR-49C).

(c) Carrier Receiving Logic (Figure 28)

This logic includes a contact converter CC and logicAND-44. Output “trip” (or unblocking) frequency sig-nal from the carrier receiver operates the contactconverter and will produce a carrier trip, CR, signalfrom AND-44.

(d) Channel Indicators (not shown in Figure 28)

The memorized SEND indicator will be displayedafter breaker trip and frequency shift to trip orunblocking by the transmitter during the fault. Thememorized RCVR indicator will be displayed after thebreaker trips and a carrier trip signal was receivedfrom the receiver.

(e) Channel Simulation (not shown in Figure 28)

The test function selection provides the capability tosimulate the TK switch function for keying action viaOR-18 and AND-35 without the operation of pilotrelay units, and to simulate the RS switches functionfor receiving of a trip or unblocking frequency signalaction without the operation from the remote trans-mitter.

(f) TBM, Transient Block and Unblock Logic(Figure 36)

For a loop system or paralleled line applications,power reversal may introduce a problem to the pilotrelay system, especially when a 3-terminal line isinvolved, since the distance units may have to be setgreater than 150% of ZL in order to accommodatethe infeed effect from the tapped terminal. They maysee the external fault on the parallel line when thethird source is out of service. The transient block andunblock logic, TBM, is for solving this problem.

Field experiences show that the reverse power mayalso be occurred transiently on a single circuit appli-cation under unequal-pole external fault clearing con-dition. On an external ground fault, when theadjacent line breaker trips, it interrupts the faultedphase as well as the load currents in the unfaultedphases. Dependent on the direction of the load cur-rent, and the asymmetry of the breaker, there can bea short pulse of load-derived Io with possible “trip-ping direction” polarity, which provides an electrical

forward torque to the ground directional relay. There-fore, for security reason, the setting of “RBSW” onMDAR (REL-300) version 2.10 has been removedfrom the logic and the software (some older ver-sions need to set RBSW to YES). Once the POTTsystem is selected, the transient blocking andunblocking logic will automatically be activated.

MDAR (REL-300) POTT scheme uses reverse-block approach for the TBM logic, as shown inFigure 36. For activating the TBM logic, the zone-3 distance units should be set to reverse, i.e. setZ3FR = REV. The TBM logic, Figure 36, consists ofthe reverse setting zone-3 distance units, AND-172,AND-9B, OR-9A, AND-45A and the 0/50 ms timer.

(g) Programmable Reclosing Initiation, (Figure 24)

The basic programmable RI application is asdescribed in Chapter IX. However, on pilot systems,to activate the RI2 on any 3-pole trip, the externalpilot enable switch should be ON, and both the PLTand Z1RI should be set to YES. The operation willoccur via the logic AND-89, AND-84 and OR-84A, asshown in Figure 24.

10.1.2 Permissive Underreach Transfer TripSystem (PUTT)

The basic operating principles of a PUTT system are:

(a) The pilot relays, PLTP/PLTG, are set to over-reach,

(b) The pilot channel is a frequency shift typedevice, and

(c) The transmitter frequency need not to be differ-ent at each terminal. Its signal may be througheither metallic wire or microwave.

(d) Channel is normally operated with a guard fre-quency. The channel frequency will be shiftedfrom guard to trip when the Zone-1 reach relay,Z1P/Z1G, operates, and

(e) Pilot trip is performed when the pilot relay(s),PLTP and/or PLTG operates, together with thereceiving of a carrier trip signal from the remoteend.

The PUTT system includes the following logic. Thefunctional display STYP should be selected to PUTT.The TBM logic is not required for this schemebecause the carrier keying units are set for under-reach.

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(a) Tripping Logic

The tripping logic for the PUTT scheme is exactly thesame as for the POTT scheme. (Figures 26, 29)

(b) Carrier Keying Logic

(1) Forward fault keying (Figure 29)

For a forward end zone fault, the PUTTscheme will not key unless the internalfault is within the Zone-1 reach. Thismeans that the PUTT scheme keys onlyon Zone-1 faults. The keying will occurvia AND-46, OR-18 and AND-35.

(2) Signal continuation (Figure 29)Same as for POTT scheme.

Note: For open breaker condition, the echo key-ing will not work due to lack of the “SEND”signal from the remote terminal for an endzone fault. The remote terminal relies onZone-2 to clear the fault.

(c) Carrier receiving logic (Figure 29)Similar to POTT scheme.

(d) Channel indicatorsSimilar to POTT scheme.

(e) Channel simulationSimilar to POTT scheme.

(f) TBMThere is no power reversal problem on PUTTscheme.

(g) Programmable Reclosing Initiation (Figure 24)Same as for POTT scheme.

10.1.3 Directional Comparison Blocking System(BLK)

If the functional display “STYP” is selected to BLK,the MDAR (REL-300) will perform the blockingscheme.

The following IMPORTANT settings are recom-mended for blocking system:

OSC = Z2Z3

FDAT = TRIP

PLT = YES (must)

STYP = BLK (must)

FDGT > 3 cycles

Z3FR = REV (must)

The basic operating principles of a directional com-parison blocking system, BLK, are:

(a) The pilot relays, PLTP/PLTG, are set to over-reach,

(b) The Zone-3 relays, Z3P/Z3G, should be set inthe reverse direction (Z3FR = REV) to detectthe reverse external faults and for carrier start.Referring to Figure 30, the MDAR (REL-300)blocking scheme also uses ∆I, ∆V and RDOGinformation to start the carrier. The use of highspeed ∆I and ∆V signals for carrier start pro-vides more security to the scheme.

(c) Pilot channel is an ON-OFF type power linecarrier. Transmitter frequency at each terminalcan be the same.

(d) Channel is normally OFF until the carrier startunit(s) senses the fault and starts the transmit-ter.

(e) Pilot trip is performed when the pilot relay(s)operates and a carrier blocking signal is notreceived.

The operating principle of the pilot distance measure-ment units, PLTP/PLTG are the same as the non-pilotzone distance measurement units, and are super-vised by the same LOPB, OSB, FDOP, FDOG, IMand IoM units as shown in Figure 26.

For more dependability on high Rf faults, the pilotground PLTG trip logic is supplement with the FDOGand IoM units, as shown in Figure 26. The direction ofthe forward directional overcurrent ground unit,FDOG, is determined by setting the DIRU to ZSEQ,NSEQ or DUAL. The delay timer FDGT has a rangeof 0 to 15 cycles, in 1.0 cycle steps. It can be blockedby setting the FDGT to BLK.

The pilot distance unit, PLTG, is always active andhas the priority for tripping, therefore, practically, theFDGT timer should be set to 3 cycles or longer forsecurity reason.

The pilot phase and/or pilot ground function(s) canbe disabled by selecting the PLTP and/or PLTG toOUT. (note, the FDOG pilot trip function will also bedisabled when PLTG set to OUT).

The BLK system, as shown in Figure 30, includes thefollowing portions:

(a) Tripping Logic (Figure 26

(1) For a forward internal fault, the local pilotrelay(s), PLTP and/or PLTG, sees thefault. Output signal of OR-40 disablesand stops the carrier start circuit (note,the ∆I and ∆V starts the carrier before

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the distance unit picks up) via OR-16, 0/150 ms squelch timer, AND-50 andAND-41D to prevent the local transmitterfrom starting (note, the receiver receivesthe signal from both local and remotetransmitters). At the same time, output ofOR-40 will satisfies one input of AND-48,and also start the channel coordinationtimer (BLKT, range 0 to 98, in 2 mssteps).

After the preset time of the channel coor-dination timer, logic AND-47 satisfiesAND-48 if there is no carrier signalreceived from either remote or local oninternal faults, and if the local TBM (tran-sient block circuit) does not set up. Then,AND-48 output will satisfy AND-52 andwill produce pilot trip via OR-2 (Figure15). Pilot trip targets PLTP/PLTG will beturned on after the breaker tripped.

(2) For a forward external fault, the local pilotrelay(s), PLTP and/or PLTG, sees thefault and operates in the same manneras for the forward internal faults. How-ever, at the remote terminal, the carrierstart units ∆I, ∆V, Z3P(R), Z3G(R) orRDOG/IOS also see this external faultand turns on the transmitter via AND-50,OR-41, AND-51, OR-18 and AND-35,sending a blocking signal to the localand remote terminals. The local receiverreceives the blocking signal, disables theoperation of AND-47. Therefore, AND-48will produce no carrier trip signal forAND-52.

(b) Carrier Keying Logic

(1) Reverse fault keying (Figure 30)

For a reverse fault, the ∆I and ∆V as wellas the local reverse looking relay(s)Z3P(R)/Z3G(R) or RDOG/IOS, see thefault, operates the SEND relay andstarts the transmitter, sending a blockingsignal to the other terminals. This keyingcircuit includes logic OR-50A, AND-50,AND-173, OR-41, AND-51, OR-18 andAND-35.

The signal of 52b to AND-35A is for dis-abling the SEND circuit when thebreaker is open and line side potential isused.

Since the present keying practice on aBLK system uses either contact open(negative or positive removal keying) orcontact close (positive keying) approach,a form C dry contact output for SEND isprovided in MDAR (REL-300).

(2) Signal continuation and TBM logic(Figure 30)

On a reverse fault, both the local carrierstart unit(s) and the remote pilot relaysee the fault and operate.

The local carrier start unit(s) starts thecarrier and sends blocking signal toblock the remote pilot relay from tripping.After the fault is cleared by the externalbreaker, the remote breaker may have atendency to trip falsely if the carrier startunit resets faster than the pilot trip unit.The 0/50 ms timer between the OR-41Dand AND-51 holds the carrier signal onfor 50 ms after the carrier start unitshave been reset for alleviating this prob-lem.

This logic also provides TBM (transientblock and unblock) on power reversal.

(3) Internal fault preference and squelch(Figure 30)

On an internal fault, the ∆I and ∆V sig-nal(s) also start the transmitter for 65ms.This operation may block the systemfrom pilot tripping. The output signalfrom OR-40 to OR-16 and logic OR-16to AND-120 will provide an internal faultpreference feature for solving this prob-lem.

The squelch 0/150 ms timer is requiredfor improving the problem if the localbreaker tripped faster than the remotebreaker on an internal fault. The logicholds the carrier key circuit in the “stop”mode for 150 ms after any high speedtripping, including pilot trip, Zone-1 tripand instantaneous overcurrent trip.

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(c) Carrier receiving logic (Figure 30)

Carrier signal from the receiver output will bedirectly applied to AND-47 to disable the pilottripping function.

(d) Channel indication (not shown inFigure 30)

Since the carrier channel turns on for externalfaults only, the channel indicators, SEND andRCVR, are not memorized.

(e) Channel simulation (not shown inFigure 30)

The test function provides the capability to sim-ulate the TK switch function for keying actionvia OR-18 and AND-35 without the operation ofthe pilot relay units, and to simulate the RSswitch function for receiving of a blocking signalwithout the operation from the remote transmit-ter.

(f) Programmable Reclosing Initiation(Figure 24)

Same as for POTT scheme.

10.2 WEAKFEED TRIP APPLICATION

10.2.1 The logic for a weakfeed terminal is notrequired for the BLK system. The BLK systemrequires no permissive trip signal from the remoteend, even though the remote end is a weakfeed ter-minal. The strong end has no problem for tripping aninternal fault. The weak end is usually assumedeither as a “no feed” source, for which it does notneed to trip on an internal fault, or that it can pilot tripsequentially.

However, the enhanced TBM logic, as described inabove paragraph (10.1.3(b)(2)), may overblock aninternal fault from tripping on weakfeed condition.The WFEN should be set to YES in order to disablethis enhanced logic.

10.2.2 The logic for a weakfeed terminal is notrequired for the PUTT system, because the PUTTsystem uses an underreaching relay(s) only for pilottrip keying, it is impossible to apply this scheme toprotect a system which may have weakfeed condi-tion.

10.2.3 For POTT and unblocking schemes on theweak source terminal

(a) The Z3P/Z3G distance relays should be set forreverse looking, and

(b) the undervoltage units, VAL, VBL, VCL shouldbe used.

The basic operating principle of the weakfeed triplogic for the POTT and simplified unblocking schemeis as follows:

(A) Echo key for trip permission (Figure 33)

On internal faults, the strong source end sends thetrip (or unblocking) frequency signal to the weak end,and its pilot trip relay(s) will trip, once it receives anecho trip permission from the weak end. The pilot triprelay(s) at the weak end cannot pick up due to notenough internal fault energy, and does not performthe normal keying function.

(3) With one weakfeed condition, when theweak end receives trip or unblocking sig-nal, the output from the receiver oper-ates the echo key logic AND-65,providing both the pilot relay (from OR-40) and the reverse looking relay (fromOR-41A) do not pick up, and if systemdisturbance is detected (VV or VI). Out-put of AND-65 will key the weak terminaltransmitter to the trip or unblocking fre-quency via OR-18 and AND-35.

(4) On a weak end reverse external fault, thestrong source end sends the trip (orunblocking) frequency signal to the weakend, and its pilot trip relay(s) is waitingfor the receiving of the echo trip permis-sion from the weak end. However, at theweak end the echo key logic AND-65 willnot operate, because the reverse lookingrelay operation sends no echo signal tothe strong end. Both the strong/weakends will not trip on this external fault.

(B) Weak end trip on internal fault (Figure 33)

Output of AND-65 (start echo keying), together withno output from OR-40 (pilot trip relays) and with out-put from OR-44 (low voltage condition) will satisfyAND-66. Weakfeed trip will be performed after 50 msvia OR-2. The timer delay is for coordination becausethe voltage trip units are non-directional.

(C) Single-pole trip, SPT (Figure 38)

The single-pole-trip function includes the following

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features:

(1) SPT/SRI on first fault.

(2) 3PT/RB if reclosing on a permanentfault.

(3) 3PT/RB if second phase(s) fault duringsingle-phasing.

(4) 3PT on a preset time limit (62T) if thesystem fails to reclose.

(5) Trip/RI mode selection.

The functional display TTYP settings, OFF/1PR/2PR/3PR/SPR/SR3R provide the following operatingmode selections:

TTYP TRIPPING MODE RECLOSING INITIATE

OFF 3PT on all faults No reclosing1PR 3PT on all faults RI2 on ØG faults only2PR 3PT on all faults RI2 on ØG/ØØØ/ØØG faults3PR 3PT on all faults RI2 on all faultsSPR SPT on ØG faults, RI1 on ØG faults only,

3PT on others no reclosing on othersSR3R SPT on ØG fault, RI1 on ØG faults,

3PT on others RI2 on others

where RI1/RI2 are separated output contacts forexternal application.

The SPT logic as shown in Figure 38 is proposed byEPRI/China. Its design is based on the power systemoperation practices and experiences in China.

The pole-disagreement circuit does not use 52a/52bcontacts. It uses the MDAR (REL-300) trip signalsTRSLA, TRSLB, TRSLC and the resetting of faultphase current signals IA, IB, IC for identifying thepole-disagreement condition.

Refer to Figure 38, the pole-disagreement signalsXA1, XB1, XC1 will be used for disabling the faultedphase impedance units, Z1G/Z2G/Z3G /PLTG(includes FDOG/IoM), for 1 to 6 seconds in 1.0 sec-ond steps (based on the SPTT timer setting) oncethe faulted phase has been tripped.

Provision for connecting the external signals XTRIPA,XTRIPB, XTRIPC for initiating the MDAR (REL-300)pole-disagreement logic if breaker is operated byother SPT protection. This logic includes OR-78D,OR-78E, and OR-78F.

For SPT mode, the TTYP setting should be selectedto either SPR or SR3R position. The SPT logic pro-vides the following functions:

10.2.4 Single-pole-trip (SPT) and single-pole-reclosing initiate (RI1) on ØG faults.

Refer to Figure 38, for example, on an AG-fault, theØA ground distance ZA and IoM units operate. Thisprovides an output signal from OR-2. 3-pole trip(3PT) path of AND-68 is inhibited by the presence ofno 3PTN signal to AND-68, since TTYP is set ateither SPR or SR3R (refer to system drawing2687F04 sheet 1). SPT ØA occurs via AND-69because the faulted phase selector AG-unit picks up.Single-pole-reclosing initiate unit RI1 picks up viaAND-85 (Figure 24) after the faulted pole trip circuithas been energized.

The FDOG path is for the detectionof single phasewith high resistance to ground fault. for the phase-phase-ground fault condition this path may beblocked if the setting of TTYP=SRP or SR3Rbecause the phase selector shows a fault type ofphase-phase fault and it expects the Z1P or PLTP triponly. (Refer to Figure 38 gate AND 48E.)

10.2.5 Three-pole-trip and reclosing block (RB) onunsuccessful reclosing.

On an unsuccessful single-pole reclose, the reclose-on-fault, ROF signal, will trip 3-pole by the output sig-nal from AND-75D. ROF is identified by the combinedinformation of fault current and pole-disagreementsignals, i.e. XA1/IAM, XB1/IBM, XC1/ICM and IoM.This logic includes AND-75A, AND-75B, AND-75C,OR-75, AND-75D and the 60/0 timer in Figure 38.ROF trip will also initiate RB and with CIF target.

10.2.6 Three-pole-trip and reclosing block on“sound phase fault” (SPF) during single-phasing.

Once the SPT has been performed, the pole dis-agreement circuit sets the X2 signal via OR-75F. SPFtrips 3-pole by the output signal of S3PT via AND-77(Figure 38) if a sound phase(s) fault occurs duringsingle-phasing. Reclosing block RB will be initiatedby S3PT signal and via logic OR-61, OR-86A andAND-86B in Figure 24.

10.2.7 Three-pole-trip and reclosing block when thesingle phasing limit timer is timed out.

In case of malfunction on the external reclosingscheme, three-pole trip and RB will be performed by

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the output signal of S3PT after the single-phasing-limit-timer (62T) times out, to prevent overheating ongenerator(s). The range of the 62T timer is 300-5000ms in 50 ms steps. Its setting should be based on thegenerator's (I2)2t capability.

10.2.8 Three-pole-trip (3PT) with three-pole-reclos-ing initiate (RI2) on all multi-phase faults.

Refer to Figure 38, for example, on an AB-fault,P3PT signal from AND-76 will trip 3-pole. Three-pole-reclosing initiate (RI2) will pick up if the TTYP isselected to 2PR, 3PR or SR3R.

10.2.9 Three-pole-trip occurs with or without three-pole-reclosing initiate on all faults if the func-tional display trip-mode selector “TTYP” isnot selected to SPR or SR3R.

10.3 16 OSCILLOGRAPHIC RECORDS


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11.1 COMMUNICATION ATTACHMENTS

An output is provided which will allow communica-tions between the MDAR (REL-300) system andexternal devices for data communications, network-ing and remote setting. Two types of PONI (ProductOperated Network Interface) for interfacing are avail-able depending on the application:

(a) Interfacing by using an RS-232C-PONI allowsthe MDAR (REL-300) communications to becompatible with an IBM-PC.

(b) Interfacing by using a INCOM®1-PONI permitsthe MDAR (REL-300) to be addressable and toshare a local area network on a single wire pairbasis to make common use of a modem.

The PONI attachment is mounted on the backplate ofthe outer chassis and connected to the backplanemodule. It can be accessed from the rear panel.

An IBM XT or AT compatible computer, with a specialsoftware “WRELCOM” provides for obtaining orsending the setting information to the MDAR (REL-300). It also can be used to monitor or change thesettings, 16 fault records, 16 intermediate targetrecords, oscillographic data and metering informa-tion.

The MDAR (REL-300) front panel shows two faultevents (last and previous), but thru the remote com-munication, 16 fault events and 16 record of interme-diate target data can be obtained and stored.

For a remote setting, SETR should be set to YES;then the settings can be changed remotely with auser-defined password. If a user loses his assignedpassword, a new password can be installed by turn-ing the MDAR (REL-300) relay's dc power supply“OFF” and then turn ON. MDAR (REL-300) allows achange of password within the next 15 minutes, byusing a default PASSWORD. Refer to WRELCOMmanual for detailed information.

When in the remote mode, the computer can disable

1. “INCOM” is a registered trademark of the WestinghouseElectric Corporation, Inc., which stands for INtegratedCOMmunications.

the local setting by showing SET = REM (in themetering mode). Then, the setting cannot bechanged locally. In this situation, the only way tochange a setting locally would be to turn the dcpower OFF and

then ON. The computer will allow for a local settingchange within 15 minutes.

IMAC, an optional separate unit, stands for INCOMMulti Access Controller, is a substation based com-puter which can access the relays on the network,automatically monitor relay status and provideremote communication through a telephone modem.It includes a CRT and printer.

11.2 16 FAULT RECORDS AND INTERMEDIATETARGETS.

The MDAR (REL-300) system saves the latest 16fault records. The latest two fault records can beaccessed either via the front panel or via the commu-nication port. The fault records 3 to 16 can only beaccessed via the communication port. On the frontpanel, the “LAST FAULT” information is of the lastfault, the “PREVIOUS FAULT” information is of theprevious fault. These displays contain the targetinformation along with the “frozen” data at the secondcycle of the fault. When targets are available, theLAST FAULT LED flashes. It flashes once per secondif only the LAST FAULT contains targets. It will flashtwice per second if 2 or more fault records are con-tained.

The activation of fault data storage is controlled bythe selection of TRIP/Z2TR/Z2Z3 in the FDAT func-tion, where

TRIP — start to store fault data only if tripaction occurs.

Z2TR — start to store fault data if Zone-2 unitpicks up or any trip action occurs.

Z2Z3 — start to store fault data if Zone-2 orZone-3 unit picks up or any trip actionoccurs.

The fault records are stored in non-volatile memoryand are retained even if relay is deenergized. Theserecords can be deleted only by applying a rated volt-

Section 11. COMMUNICATION, FAULT DATA, INTERMEDIATE TARGETAND OSCILLOGRAPHIC INFORMATION

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age to the External Reset Terminals (TB5/5 and TB5/6), or through a remote communication interface. Bypressing the front panel RESET TARGETS pushbut-ton, the flashing LED will be reset to Metering mode,and the fault information will still be retained.

Each record of the intermediate target data contains8-cycle information (1-prefault and 7 post-fault), with7 analog inputs and 24 digital data (at the samplingrate of 8 per cycle).

The intermediate target data is stored in a temporarymemory and will be lost when relay is deenergized.The intermediate target data can only be obtainedthrough remote communication. If OSC is included,the intermediate target data is provided 8 sample percycle. If OSC is not included, the intermediate targetdata is provided one sample per cycle.

11.3 16 OSCILLOGRAPHIC RECORDS

The oscillographic record has 8 samples per cycle, 1cycle pre-trigger and 7 cycles post-trigger. It includes7 analog and 24 digital intermediate targets (testpoints) for each of the 16 oscillographic records. Therecords are stored in a temporary memory and willbe lost when the relay is deenergized. The data can

be accessed via the communication port only.

The oscillographic data taken is controlled by theselection of TRIP/Z2TR/Z2Z3/∆I∆V in the OSC func-tion, where

TRIP — Data are taken only if trip actionoccurs. The data collection is startedfrom ∆I∆V if the trip occurs within 7cycles.

Z2TR — The data collection is triggered byZone-2 pickup or any trip actionoccurs.

Z2Z3 — The data collection is triggered byZone-2 or Zone-3 unit pickup, or anytrip action occurs.

∆I∆V — The data collection is triggered by any∆I, ∆V, Zone-2 or Zone-3 pickup, orany trip action occurs.

Note: Setting at ∆I∆V is not recommendedbecause a lot of meaningless data will bestored, such as breaker switching, etc.

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12.1 SELECTABLE LOSS-OF-LOAD ACCELER-ATED TRIP (LLT).

The load-loss speedup Zone-2 trip logic sensesremote 3-pole clearing on all faults except 3∆ to com-plement or substitute for the action of the pilot chan-nel, to speed up trip at the slow terminal.

12.2 PILOT GROUND TRIP

Pilot Ground Trip is more dependable on high Rffaults because it is supplemented with FDOG/IoM(refer to Figure 34). Trip delay is controlled by the set-ting of the FDGT timer (Forward Directional Overcur-rent Ground Timer). The range of this timer is 0 to 15cycles in 1 cycle steps and with BLK step for dis-abling this trip function if required. The pilot distanceunit PLTG is always active and has the priority fortripping, therefore, practically, the FDGT timer shouldbe set to 3 cycles or longer for security reason.

12.3 THE REVERSE-BLOCK FEATURE

The Reverse-Block feature makes the high speed tripground unit Z1G more secure on unequal pole clear-ing on reverse faults, as shown in Figure 36.

12.4 PILOT GROUND

Pilot ground is more secure on POTT/unblockingschemes on some special power system conditions,such as shown in Figure 35.

When a ØØG fault is on the paralleled line section,due to the system condition, fault current flowing inthe protected line would be I1+I2 from A to B, and Iofrom B to A.

The operation of pilot distance relays would include aphase relay at A and a ground relay at B. The resultwould be erroneous directional comparison of anexternal fault as an “internal” one. The POTT andunblocking scheme will incorrectly trip out the pro-tected line.

MDAR (REL-300) pilot ground unit(s), PLTG/FDOG,is supervised by the reverse looking ground unitRDOG. The “reverse-block” logic is as shown in Fig-ure 36. At terminal A, the RDOG disables the PLTG/

FDOG trip/key function via OR-9A, AND-45A, AND-30 and AND-45. At terminal B, it will receive no car-rier signal for permissive trip. The reverse-block logicalso provides the conventional TBM feature to pre-vent false operation on power reversal.

It should be noted that a “block-the-block” logic isalso included in the circuit as shown in Figure 36.The block-the-block logic is to prevent the reverse-block logic from overblocking, as a result of the fol-lowing system condition.

For example, the breaker is unequal-pole closing ona ØG fault, i.e. pole A, then B, C. Referring to Figure37, if, due to breaker contact asymmetry, the firstbreaker contact to close is the one on the faultedphase, the zero sequence (or negative sequence)polarizing voltage will initially have a polarity oppositeto its fault-derived polarity. The reverse-lookingground unit could pick up for a short period, issue ablocking order and maintain it for 50 ms. Conse-quently, the correct tripping will be delayed. Theblock-the-block logic would prevent this delaying. Thereverse-block logic also includes the reverse lookingZ3P/Z3G units as shown in Figure 36.

12.5 THE BLOCKING SYSTEM

The Blockin system is more secure by using thefaster ∆I and ∆V information for carrier start.

12.6 SECURITY LOGIC FOR REVERSE FAULTWITH FAULT RESISTANCE.

There is an inordinately high influence of ct leadresistance for a low voltage MPS test when using theMotor-Generator set as one of the test sources. Itproduces virtually a 90° phase shift in the polarizingvoltage with respect to the angle between sources,causing undesired operation. Even though this is anMPS-related phenomenon and would pose no prob-lem for an actual power system, a forward phasedirectional function FDOP is included in the design toprevent this from occurring. (Refer to Figure 25,AND-144C and AND-144D).

Section 12. UNIQUE FUNCTION OF MDAR (REL-300)VERSION 2.60 SYSTEMS

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The phase directional unit FDOP is based on theangular relationship of a single-phase current andthe corresponding phase-to-phase voltage phasors.The forward direction is identified if the current pha-sor leads the voltage phasor. The pair of current andvoltage phasors which are compared are IA and VBA(FDOPA), IB and VCB (FDOPB), IC and VAC(FDOPC).

12.7 PROGRAMMABLE RECLOSING INITIATIONWITH LOGIC FOR RB ON BF SQUELCH.

12.8 COMMUNICATION — REFER TO CHAP-TER XI FOR DETAIL.

12.9 UNIQUE OSB AND SPT LOGIC TO MEETTHE POWER SYSTEM OPERATION PRAC-TICES IN CHINA.

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Assume that the protected line has the followingdata:

18.27 miles, line reactance 0.8 ohms/mile, 69 KV, 60cycles. Positive and negative sequence impedances:

Z1L(Pri) = Z2L(Pri) = 15∠77˚ ohms

Zero sequence impedance: ZoL(pri) = 50∠73˚ ohms.

Current transformer ratio: RC = 1200/5 = 240,Set MDAR (REL-300) CTR = 240

Voltage transformer ratio: RV = 600/1 = 600,Set MDAR (REL-300) VTR = 600

Relay secondary ohmic impedances are:

Z = ZPri x RC/RV

Z1L = Z2L = 15∠77˚x 240/600 = 6∠77˚ ohms

Z0L = 50∠73˚ x 240/600 = 20∠73˚ ohms.

13.1 Calculations and settings:

(a) The ratio of zero and positive sequence imped-ances

ZR = Z0L/ Z1L = 20/6 = 3.33,

Set MDAR (REL-300) ZR = 3.3,

PANG = 77,

GANG = 73.

then, MDAR (REL-300) will automatically cal-culate the zero sequence current compensa-tion factor ko by using the value of ZR, PANGand GANG, i.e.

ko = (Z0L - Z1L)/Z1L = (ZR/PANG-GANG - 1)

(b) Zone-1 distance unit settings:

A setting of 80% of the line impedance forZone-1 reach is recommended, thus the Zone-1 phase and ground reach should be

Z1P = 6 x 0.8 = 4.8 and

Z1G = 6 x 0.8 = 4.8

Set MDAR (REL-300) Z1P = Z1G = 4.80

Note: Z1P and Z1G can be set for different val-ues as the application requires. Refer to

section H, step 10 for calculation and ex-ample. Either Z1P or Z1G can be disabledindependently by setting it to OUT posi-tion if this function is not needed.

(c) Zone-2 distance units settings:

Generally, Zone-2 reach is set to underreachthe shortest adjacent line off the remote bus. Apractical setting is set for 100% of the pro-tected line plus 50% of the shortest adjacentline off the remote bus. For this example, if theshortest adjacent line primary impedance is 20ohms, then the Zone-2 reach setting would be:

Z2P = 6 + (20 x 0.5) x 240/600 = 10 and

Z2G = 10

Set MDAR (REL-300) Z2P = Z2G = 10.00

Note: Z2P and Z2G can be set for different val-ues as the application requires. Either Z2Por Z2G can be disabled independently bysetting it to OUT position if this function isnot needed.

(d) Zone-3 distance unit settings:

Generally, Zone-3 reach is set to underreach ofthe shortest zone-2 reach of the adjacent lineoff the remote bus. A practical setting is set for100% of the protected line plus 100% of theshortest adjacent line off the remote bus. Forexample, if the shortest zone-2 reach off theremote bus is 25 ohms primary, and infeedeffect may increase its impedance by 30%,then the Zone-3 reach setting should be:

Z3P = 6 + (25 x 1.3) x240/600 = 19 andZ3G = 19

Set MDAR (REL-300) Z3P = Z3G = 19.00

Note: Z3P and Z3G can be set for different val-ues as the application requires. Either Z3Por Z3G can be disabled independently bysetting it to OUT position if this function isnot needed.

(e) Pilot distance unit settings:

The pilot zone distance phase and ground

Section 13. MDAR (REL-300) SETTING CALCULATIONSAND SELECTIONS

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reaches can be set either exactly or nearlyequal to the Zone-2 phase and ground dis-tance reach, which depends on the application.For this example, set it equal to Zone-2 reach,i.e.,

PLTP = 10 and PLTG = 10

Set MDAR (REL-300) PLTP = PLTG = 10.00

Note: PLTP and PLTG can be set for different val-ues as the application requires. EitherPLTP or PLTG can be disabled indepen-dently by setting it to OUT position if thisfunction is not needed.

(f) Overcurrent unit settings

(1) The low set phase overcurrent unit is usedfor supervising the load-loss-trip and theCIF functions. It should be set higher thanthe line charging current and below theminimum load current if LLT function isapplied, (note, it should be set above themaximum tapped load current if applica-ble).

These units can be set to higher than themaximum load current if LLT function isnot applied.

Assume that the line charging current isnegligible for this line section, and the min-imum load current is 2.0 amperes second-ary. Then the low set phase overcurrentunit setting should be:

IL = 1

Set MDAR (REL-300) IL = 1.0

(2) The medium set phase overcurrent unit isused for supervising the OSB function andall the phase distance units. This unitshould be set not to limit the zone-3 reach,but traditionally, its setting should be sethigher than load current.

Assume that 4.5 amperes has no effect tothe zone-3 reach, and the maximum loadcurrent is 4.0 amperes, then the mediumset phase overcurrent unit can be set to:

IM = 4.5

Set MDAR (REL-300) IM = 4.5

(3) The low set ground overcurrent unit isused for supervising the reverse direc-tional ground overcurrent unit (RDOG). Itshould be set as sensitive as possible. Asetting of 0.5 amperes is recommended:

IOS = 0.5

Set MDAR (REL-300) IOS = 0.5

(4) The medium set ground overcurrent unit isused for supervising the Zone-1, Zone-2,Zone-3 and pilot ground distance units(Z1G, Z2G, Z3G, PLTG) and the forwarddirectional ground overcurrent unit(FDOG).

Generally, it is recommended to be set 2Xof the remote terminal IOS setting (if iden-tical CT ratio is at both ends):

IOM = 2X IOS = 1.0

Set MDAR (REL-300) IOM = 1.0

(g) The high set overcurrent phase and groundunits, ITP and ITG, are used for direct trip func-tion. The general setting criteria for the instan-taneous direct trip unit is:

(1) the maximum load or the maximumreverse fault current should not be higherthan the maximum forward end Zone faultcurrent, and

(2) the unit should be set higher than 1.15times the maximum fault on the remotebus, where the factor of 1.15 is to allow fortransient overreach. For this example,assuming that the maximum load or themaximum reverse fault current is nothigher than the maximum forward endZone fault current, and the maximumphase and ground fault currents on theremote bus are 20 and 24 amperes,respectively, then the settings of the highset phase (ITP) and the high set ground(ITG) should be:

ITP = 20 x 1.15 = 23and ITG = 24 x 1.15 = 27.6

Set MDAR (REL-300) ITP = 23.0,ITG = 27.5

Note: Either ITP or ITG can be disabled indepen-dently by setting it to OUT position if thisfunction is not needed.

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(h) OSB blinder settings, RT and RU:

The requirements for setting the blinder unitsare:

(1) Inner blinder must be set to accommo-datemaximum fault resistance for internal3-phase faults.

(2) Inner blinder should not operate on severestable swings.

(3) Outer blinder must have adequate separa-tion from inner blinder for the fastest out-of-step swing to be acknowledged as anout-of-step condition.

(4) Outer blinder must not operate on load.

(i) Setting the Inner Blinder (for heavy load restric-tion):

If the OSB is used to supervise tripping of the3Ø-unit on heavy load current, the inner blind-ers 21BI must be set sufficiently far apart toaccommodate the maximum fault arc resis-tance. A reasonable approximation of arc resis-tance at fault inception is 400 volts per foot. If amaximum ratio of “line voltage per spacing” is10,000 volts/ft. for a high voltage transmissionline, minimum internal 3-phase fault current iscalculated as:

Imin. = [E / 1.73(ZA+ZL)]

where ZA is max. source impedance, ZL is lineimpedance andE is line-to-line voltage.

then, Rmax.= 400 x FT. / Imin.= 400x1.73(ZA+ZL) / 10000= 0.0693(ZA+ZL)

Adding a 50% margin to cover the inaccuraciesof this expression.

Rmax. = 0.104(ZA+ZL) primary ohms.

RS = 0.104(ZA+ZL)RC/RV secondaryohms.

Set inner blinder to

RT = RS x COS(90° - PANG) (1)

This is the minimum permissible inner blindersetting, where it is used to provide a restrictedtrip area for a distance relay.

Another criteria that may be considered is

based upon the rule of thumb that stableswings will not involve an angular separationbetween generator voltages in excess of 120°.This would give an approximate maximum of

Zinner = (ZA+ZL+ZB)/(2x1.73)

= 0.288(ZA+ZL+ZB) pri. ohms.

Zinner = 0.288 (ZA+ZL+ZB)RC/RV sec. ohms. (2)

Where ZB is the max. equivalent source imped-ance at the end of the line away from ZA.

An inner blinder setting between the extreme ofequations (1) and (2) may be used. This pro-vides operation for any 3-phase fault with arcresistance, and restraint for any stable swing.Except in those cases where very fast out-of-step swings are expected, the larger settingcan be used. It will usually be possible to usethe minimum inner blinder setting of 1.5 ohms.

Set MDAR (REL-300) RT = 1.50

(j) Setting the Outer Blinder (for OSB function):

For slow out-of-step swings, a reasonablyclose placement of the outer to the innerblinder characteristic is possible. The separa-tion must, however, be based on the fastestout-of-step swing expected. A 50 ms interval isinherent in the out-of-step sensing logic, andthe outer blinder must operate 50ms or moreahead of the inner blinder.

Since the rate of change of the ohmic valuemanifested to the blinder elements is depen-dent upon accelerating power and systemWR2, it is impossible to generalize. However,based on an inertia constant (H) equal to 3 andthe severe assumption of full load rejection, amachine will experience, assuming a uniformacceleration, an angular change in position ofno more than 20o per cycle on the first half slipcycle.

If the inner blinder were set for (0.104ZT), andthe very severe 20° per cycle swing rate wereused, the outer blinder should be set forapproximately:

Zouter = 0.5 ZT primary ohms

where ZT = ZA + ZL + ZB.

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This is the minimum setting of the outer blinderfor a 20° per cycle swing rate.

For this example, if Zinner = 0.104 ZT,Zouter = 0.5 ZT, RT = 1.5

Set MDAR (REL-300) RU = 7.20

(k) Overcurrent ground backup unit GB

The overcurrent ground backup unit GB pro-vides the following time curves, which are simi-lar to the CO and MCO relays, for backing upthe distance ground on high resistance groundfault.

CO-2 Short time curveCO-5 Long time curveCO-6 Definite time curveCO-7 Moderately inverse time curveCO-8 Inverse time curveCO-9 Very inverse time curveCO-11 Extremely inverse time curve

Four settings, GBCV, GBPU, GCT and GDIRneed to be determined for applying this unit.

(1) GBCV is the setting for the selection of thetime-current curve. In general, the selec-tion is based on the application and thecoordination. A selection of “OUT” dis-ables the ground back up function. In gen-eral, CO-8, CO-9 and CO-11 are normallybe used for line protection, except CO-6may be used for short line application.

(2) GBPU is the current level setting. Its rangeis 0.5 to 4.0 amperes in 0.5 steps. In gen-eral, the current level setting criteria is

(IFmin /2) > Setting Level > 2 x (Max. resid-ual load, 3Io)

where IFmin = Minimum ground fault cur-rent for a fault two buses away.

For better sensitivity, GBPU should be setat 0.5 amp. This would be adequate formost of the applications.

(3) GCT is the time delay setting of the GBunit. As shown in the relay time-currentperformance curves (not included in thiswrite-up, please refer to I.L.), There are 63setting selection, from 1 to 63 in 1.0 steps.In general, the time delay setting shouldbe coordinated with any protective devicedownstream of the line section.

(4) GDIR is the setting for directional controlselection. The GB unit will become adirectional torque control overcurrentground unit if GDIR is set at YES.

(5) The polarizing approach for the directionalground overcurrent unit is controlled by thesetting of DIRU. It has 3 selections:

ZSEQ — Zero sequence voltage polariza-tion only.

DUAL — Both zero sequence voltage andcurrent polarizations

NSEQ — Negative sequence voltage andcurrent operated.

For example, Assuming that the applica-tion needs DUAL directional control, and aCO-8 curve is required, the maximum 3Ioof unbalanced load is 0.2 amperes, theminimum ground fault current for a faulttwo buses away is 10 amperes and 0.7seconds is required for coordination withcurrent of 20 times GBPU setting, then thesettings of the GB function should be asshown below:

10 / 2 > GBPU > 2 x 0.2

Set GBPU = 0.5

From time-current performance curves, for0.7 seconds at 20 times of GBPU setting,GTC should be set to 24. Select CO-8from GBCV. Set GDIR = YES if directionalcontrol is required.

Set MDAR (REL-300) DIRU = DUAL

GBCV = CO-8GBPU = 0.5GCT = 24GDIR = YES

(l) Timer settings:

(1) Zone-1 trip delay timer T1 is normally set

Zouter

Zinner---------------

0.5000.104------------- 4.8= =

Zouter

Zinner---------------

RU

RT------- 4.8= =

RU 4.8 1.5× 7.2= =

I.L. 40-385.5

13-5

to NO, unless it is needed. For example,using MDAR (REL-300) as a non-pilot 3PTbackup with another system operated onSPT mode, then set MDAR (REL-300) T1to YES.

For example, Set MDAR (REL-300) T1 toNO

(2) Zone-2 timer T2 setting should be coordi-nated with the Zone-1 and other highspeed trip units on the adjacent line termi-nal. Coordination Time Interval, CTI, of 0.3to 0.5 seconds is recommended. Forexample, if T2 of 0.4 seconds is used, thenthe phase and ground Zone-2 timersshould be set as follow:

Set MDAR (REL-300) T2P = 0.40 andT2G = 0.40

Note: T2P and T2G are separate timers. Theycan be set at a different time setting. Also,either or both Zone-2 phase and groundfunction(s) can be disabled by selectingthe Z2P and/or Z2G to OUT; or can be dis-abled by selecting the T2P and/or T2G toBLK.

(3) Zone-3 timer T3 settings would be similarto the above. For example, if T3 of 0.8 sec-onds is required, then the phase andground Zone-3 timer should be set as fol-low:

Set MDAR (REL-300) T3P = 0.80 andT3G = 0.80

Note: T3P and T3G are separate timers. Theycan be set at a different time setting. Also,either or both Zone-3 phase and groundfunction(s) can be disabled by selectingthe Z3P and/or Z3G to OUT; or can be dis-abled by selecting the T3P and/or T3G toBLK.

(4) For the blocking system only, the setting ofthe channel coordination timer, BLKT, isbased on the application criteria

TC > (Slowest remote carrier start time +channel time + margin) - (the fastest local21P/21NP pickup time)

where channel time includes the transmit-ter and receiver times and the times whichoccur between these devices, e.g. wave

propagation, interfacing relays, etc.

For MDAR (REL-300), the fastest 21P/21NP pickup time = 14 ms the slowestcarrier start time = 4 ms and suggestedmargin time = 2 ms

For example, the MDAR (REL-300) chan-nel coordination timer can be deter-mined as below for a channel time of 3ms.

Tc = (4 + 3 + 2) - 14 = (-)

i.e., Set MDAR (REL-300) BLKT = 0

(5) For pilot systems, pilot ground trip is moredependable on high Rf faults by applyingthe FDOG/IoM/FDGT logic. Trip delay ofthis supplemented function is controlled bythe FDGT timer setting. The range of thistimer is 0 to 15 cycles in 1 cycle steps andwith BLK step. Recommend to set thistimer longer than 3 cycles.

Set MDAR (REL-300) FDGT = 3

(6) For OSB (out-of-step block), if applied, theOSTM timer setting is determined by thepower system operation practice. Its rangeis 500 and 1000 ms.

For example, set MDAR (REL-300)OSTM = 0500 if the poser systemrequires 500 ms for the logic.

(7) For single-pole trip application only, thesingle phasing limit timer setting, 62T, isfor preventing thermal damage to rotatingmachines due to the I2 component duringsingle phasing. Its range is 300 to 5000ms in 50 ms steps. The setting should bebased on the poorest (I2)2t constant of themachines in service.

For example, Set MDAR (REL-300)62T = 1.550, if 3PT is required before1.55 seconds and after one pole hasbeen open and the breaker does not, orcannot reclose.

13.2 Selections of MDAR (REL-300) settings

The following settings are determined by the applica-tion. They do not require calculation.

(1) The OSC setting is for selecting the one of the4 ways, TRIP/Z2TR/Z2Z3/∆I∆V, to initiate the

I.L. 40-385.5

13-6

oscillographic data taken.Where:

TRIP — start data taken only if trip actionoccurs.

Z2TR — start data taken if Zone-2 unitspicks up or any trip action occurs.

Z2Z3 — start data taken if Zone-2 or Zone-3units picks up, or any trip actionoccurs.

∆I∆V — start data taken if ∆I, ∆V, Zone-2 orZone-3 units picks up, or any tripaction occurs.

Note: Setting at ∆I∆V is not recommended be-cause a lot of meaningless data will bestored, such as breaker switching, etc.

For example, Set MDAR (REL-300) OSC = Z2Z3

(2) The FDAT setting is for selecting the one of the3 ways, TRIP/Z2TR/Z2Z3, to initiate the faultdata taken.Where:

TRIP — start to store fault data only if tripaction occurs.

Z2TR — start to store fault data if Zone-2units picks up or any trip action occurs.

Z2Z3 — start to store fault data if Zone-2 orZone-3 units picks up or any trip actionoccurs.

For example, Set MDAR (REL-300)FDAT = Z2Z3

(3) The frequency setting, FREQ, should beselected to match the power system operatingfrequency. For example, select FREQ = 60 ifthe power system operating frequency is 60hertz.

For this example, Set MDAR (REL-300)FREQ = 60

(4) The current transformer type setting, CTYP,provides the flexibility for 5 ampere or 1ampere rated current transformer selection.For example, select and set the CTYP = 5 if a 5ampere current transformer is used.

For this example, Set MDAR (REL-300)CTYP = 5

The setting of CTYP affects all the distanceunit and overcurrent unit setting ranges. Theranges will be automatically changed as listedin Table 1:

(5) The read primary setting, RP, should be set atYES if all the monitoring ac voltages and cur-rents are selected to be displayed in primaryKV and KA values, respectively.

For example, Set MDAR (REL-300) RP = NO

(6) The ohms per unit distance of the line reac-tance setting, XPUD, is the multiplier for fault

Table 1:

MDAR (REL-300)UNITS

At CTYP = 5 At CTYP = 1

Z1P/Z1G/Z2P/Z2GZ3P/Z3G/PLTP/PLTG

0.01-50.00,in 0.01 ohms steps

0.05-250,in 0.05 ohms steps

ITP/ITG 2.0-150.00,in 0.5 amp steps in

0.4-30.0,0.1 amp steps

IL/IM/IOS/IOM 0.5-10.0,in 0.1 amp steps in

0.1-2.0,0.02 amp steps

distance display. It has a range of 0.3 to 1.5 in0.001 steps. For this example, the line reac-tance is 0.8 ohms/mile, then Set MDAR (REL-300) XPUD = 0.800

The fault distance calculation is as follows:

Where Zs is secondary impedance magnitude,and FANG is fault angle.

(7) The setting of DTYP (distance type) has aselection of MILE and KM. It should beselected to match with the setting of XPUD. Forthis example, Select MDAR (REL-300)DTYP = MILE.

DMVTRCTR-------------

ZS FANG∠sin×XPUD

--------------------------------------------×=

I.L. 40-385.5

13-7

(8) The setting of TTYP is for selecting the reclos-ing mode on single pole trip applications (ifapplied). It has six selecting positions, OFF,1PR, 2PR, 3PR, SPR and SR3R. Refer to theguidances for reclosing mode programming forthe TTYP setting selection.

For example, Set MDAR (REL-300)TTYP = SR3R.

(9) The settings of Z1RI, Z2RI and Z3RI providethe selectivity for the Zone-1 RI (reclosing initi-ation), Zone-2 RI and Zone-3 RI, respectively.On pilot system applications, the Z1RI shouldbe set to YES if reclosing initiation is required.On non-pilot system application, set Z1RI,Z2RI and/or Z3RI to YES if RI is required whenthe particular distance zone operates.

For example, Set MDAR (REL-300)Z1RI = YES

Z2RI = NOZ3RI = NO

(10) For pilot systems, set BFRB to YES if “RB onbreaker failure squelch” feature is required.

For example, Set MDAR (REL-300)BFRB = YES

(11) The setting of PLT (pilot) combines with theexternal input signal of Pilot Enable (on back-plane panel) controls the operation of pilot andreclosing initiation. The absence of either sig-nal will:

(a) disable the pilot system,(b) block the 3RI output, and(c) allow SRI output on non-pilot system.

The PLT can be set either locally from the frontpanel, or remotely via the communicationchannel. For example, Set MDAR (REL-300)PLT = YES

(12) The STYP (system type) selects the desiredrelaying system in application. It has two selec-tions, 3ZNP (3 zone non-pilot) and Z1E (Zone-1 extension) in non-pilot MDAR (REL-300).There are five selections, 3ZNP, Z1E, POTT(permissive overreach transfer trip or Unblock-ing), PUTT (permissive underreach transfertrip) and BLK (blocking) in pilot MDAR (REL-300) version 2.60. It should be selected and setto the one which is desired.

For example, Set MDAR (REL-300)STYP = BLK

(13) For pilot MDAR (REL-300) only, the WFEN(weakfeed enable) setting should be selectedto YES for the weakfeed terminal if applicable.

For example, Set MDAR (REL-300)WFEN = NO

(14) For non-pilot system, depends on the applica-tion, the Zone-3 distance units, Z3P and Z3G,can be selected to reach forward looking orreverse looking by setting the Z3FR (Zone-3forward or reverse) to FWD or REV.

For pilot system, the zone-3 distance unitsshould be set to reverse looking for carrier start(blocking scheme) or reverse block (POTTscheme).

For example, Set MDAR (REL-300)Z3FR = REV

(15) The LV-units are used in CIFT. It should nor-mally be set to 40 volts unless a higher settingis required for more sensitive application.

For example, Set MDAR (REL-300) LV = 40

(16) Based on the power system requirement, theOSB1, OSB2 and/or OSBP can be selected toeither YES or NO.

For example, Set MDAR (REL-300)OSB1 = YES

OSB2 = YES

OSBP = YES

(17) Based on the requirements, set the CIF (close-into-fault) to YES or NO.

For example, Set MDAR (REL-300) CIF = YES

(18) Set the LLT (loss-of-load trip) to YES, FDOG orNO. Where:

YES — LLT trip with Z2 supervision.

FDOG — LLT trip with both Z2 and FDOGsupervision.

NO — LLT trip function is not used.

For example, Set MDAR (REL-300)LLT = FDOG

(19) Set the LOPB to YES if loss-of-potential blocktrip function is required.

For example, Set MDAR (REL-300)

I.L. 40-385.5

13-8

LOPB = YES

(20) Set the LOIB to YES if loss-of-current block tripfunction is required.

For example, Set MDAR (REL-300)LOIB = YES

(21) Set the AL2S to YES if trip alarm seal-in isrequired.

For example, Set MDAR (REL-300)AL2S = NO

(22) Set the SETR to YES if remote setting isrequired.

For example, Set MDAR (REL-300)SETR = YES

(23) Procedure to set the real time clock:

With MDAR (REL-300) at the setting mode,scroll the function field to TIME, and set thevalue to YES. Depress function pushbuttonRAISE to display YEAR, MNTH (month), DAY,WDAY (week day), HOUR, and MIN (minute),and set the corresponding number via thevalue field. The MDAR (REL-300) clock willstart at the time when the minute value isselected.

I.L. 40-385.5

A-1

The following kinds and quantities of test equipmentare used for the MDAR Acceptance Tests:

• Voltmeter (1)

• Ammeter (1)

• Phase Angle Meter (1)

• Load Bank (2)

• Variac (3)

• Phase Shifter (1)

• Optional Doble or Multi-Amp Test System

NOTE: Before turning on the dc power supply,check jumper positions on the Intercon-nect and Microprocessor modules asshown in Table 4-4. Also, refer to this ta-ble for relay system operation.

Check jumper #3 on the Microprocessor moduleis for the selection of phase sequence rotationABC or ACB. Remove Jumper 3 for system ABCrotation for the following test. For V2.6x rotationACB is not applicable.

Refer to the NOTE under Table A-1 for 1 amp ct ap-plication.

1. FULL PERFORMANCE TESTS

Full performance tests explore MDAR responsesand characteristics for engineering evaluation. Theyare in two parts: Non-Pilot and Pilot AcceptanceTests.

NOTE: Customers who are familiar with theMDAR performance and characteristicsshould disregard this section and pro-ceed directly to Section A-2 “Mainte-nance Tests”.

1.1 Non-Pilot Performance Tests

To prepare the MDAR relay assembly for Non-PilotAcceptance Tests, connect the MDAR per Figure A-1, Configuration 1.

1.1.1 Front Panel Check

Step 1. Turn on rated battery voltage. Check theFREQ setting to match the line frequency and cttype CTYP. Apply a balanced 3-phase voltage(70 Vac); the Alarm-1 relay should be energized.(Terminals TB4-7 and -8 should be zero ohms.)

Step 2. Check “RELAY-IN-SERVICE” LED; itshould be “ON”.

Step 3. Press “RESET TARGETS” push-button;the green LED (Volts/Amps/Angle) should be“ON”.

Step 4. Using a dc voltmeter, measure the dc volt-ages on the front panel display with respect tocommon (± 5 %).

Step 5. Press the DISPLAY SELECT pushbutton,and note that the mode LED cycles thru the fivedisplay modes. Release the pushbutton so thatthe SETTINGS mode LED is “ON”.

Step 6. Refer to Chapter 7, paragraph 7.3 for allpossible MDAR SETTINGS, and set the values inaccordance with Table A-1. For Negative Se-quence Directional Unit, change DIRU fromZSEQ to NSEQ. For dual polarizing directionalground unit, change DIRU to DUAL.

Step 7. Press the DISPLAY SELECT pushbuttonto obtain the METERING mode (VOLTS/ AMPS/ANGLE).

1.1.2 Angle Current and Voltage Input Check

Step 8. Using Figure A-1, Configuration 1, applythree ac voltages of 70 VLN and an ac current ofIA. Adjust phase A current to lag phase A voltage

(VAN) by 75°.

Step 9. Press FUNCTION RAISE or FUNCTIONLOWER pushbutton. Read input current (IA), in-put voltage (VAG), and angle (ANG). All valueswithin 5%.

NOTE: Be sure that the RP setting is “NO”. If theRP setting is “YES”, the readings will bethe primary side values (KV and KA).

! WARNING

Appendix A-1. FULL PERFORMANCE TESTS (V2.6x)

I.L. 40-385.5

A-2

The angle measurement is for referenceonly. For I<0.5A, the display of angle willbe blocked and show zero degrees.

1.1.3 Zone 1 Test/Single-Phase-To-Ground

Step 10. Using Figure A-1, Configuration 1,adjust:

V1N = 30V

V2N = 70V

V3N = 70V

MDAR goes into fault mode processing only after thecurrent detector is enabled. MDAR performscn thetest:

• Phase current (∆IA, ∆IB, or ∆IC) >1.0A peak and12.5% change

• Ground current (∆I0)>0.5 A peak

• Voltage ( ∆Van, ∆Vbn, or ∆Vcn ) >7V and 12.5%change with a current change of ∆I>0.5 A

When one of the above is true, MDAR starts fault pro-cessing. In order to perform the above, apply a certainvalue of current suddenly. If MDAR does not trip, turnthe current off, readjust to a higher value, and thensuddenly reapply current.

The current required to trip can be calculated using thefollowing:

From Table A-1:

• Z1G = 4.5 Ω• PANG = 75°• ZR = 3.0

using an X = 75° (lagging)

The current required to trip = 4.00A ± 5 % for fault cur-rent lagging fault voltage by 75°. This is the maximumtorque angle test. For other points on the MHO circle,change X to a value between 0° and 150°, and calcu-late the value of I.

See Table 4-3, for a description of the following dis-played fault data for:

• Fault Type (FTYP)

• Targets (BK1, Z1G)

IVLN

Z1GCOS PANG X–( ) 1ZR 1–( )

3--------------------+

-----------------------------------------------------------------------------------------=

• Fault Voltages (VA, VB, VC, 3V0) and Currents(IA, IB, IC, 3I0)

With the external jumper connected between TB1-13and TB1-14, the BFIA-1, BFIA-2 should be closed.The GS contact will be ON for approximately 50 ms.when the fault is applied. Alarm 2 relay will bepicked-up, which can be reset by the RESET buttonafter the fault is removed. Change TTYP to 1PR; theRI2-1 and RI2-2 should be CLOSED. Change TTYPto 2PR (or 3PR). Repeat test; RI2-1 and RI2-2should be closed. Change TTYP to “OFF”. Repeattest. RI2-1, RI2-2 should not be picked-up.

Repeat AG fault and measure the trip time, whichshould be < 2 cycles. Change the setting of T1 from0 to 3 (or N). Repeat the test; the trip time should ex-tend for an additional 3 cycles (or N cycles1). ResetT1 to zero.

The following formula can be used when PANG ≠GANG:

Vxg = (IX + K0 I0) Zcg

or Vxg = Zcg

or IX =

where

K0 =

=

IX =

or IX =

Example:

Vag = 30 Z1g = 4.5 PANG = 85

GANG = 40 Zr = 3

1.N is the number between 0 and 15.

I x

K0I x

3------------+

Vxg

Zcg 1Ko

3------+

------------------------------

ZoL Z1L–( )Z1L

-----------------------------

ZR GANG PANG–( ) -1∠

Vxg

Zcg ejPANG 1 Zr ej GANG PANG–( ) 1–3

-----------------------------------------------------------+

--------------------------------------------------------------------------------------------------------

Vxg

23--- Zcg ejPANG 1

3--- Zcg Zr ejGANG+

---------------------------------------------------------------------------------------

I.L. 40-385.5

A-3

Ia =

=

=

This is the trip current (4.3A) at the maximum torqueangle of -57.76° (current lags voltage by 57.76°).

The following equation should be used for the angleof x on the MHO circle:

Iax =

Step 11. Using Figure A-1, Configurations 2 and 3,repeat (preceding) Step 10 for BG and CG faults.Note Targets.

1.1.4 Zone 1 Test/Three-Phase

Step 12. Using Figure A-2, connect current andvoltage circuits and apply:

• VAN = 30V ∠0° IA = 6.67 ∠−75°

• VBN = 30V ∠−120° IB = 6.67 ∠−195°

• VCN = 30V ∠120° IC = 6.67 ∠+45°

Using a value of x = 75° (lagging), the current re-quired to trip is calculated as follows (Note Targets):

Since V2.6x uses IA + IB + IC to calculate 3I0, a bal-

anced 3-phase current source is recommended tobe used for this test (3I0 = 0). Figure A-2 gives a con-

cept of the test. If a Doble or Multi-Amp test set isused, be sure to synchronize the 3-phase currents.If possible, use a multi-trace storage scope to verifythe waveforms of IA, IB and IC.

In order to plot the MHO circle for different input an-gle (X), the setting of RT (and RU, if OSB option isincluded) should be at maximum (15 ohms). Refer toOSB test for detailed information. Set TTYP = 3PR.Repeat test; RI2-1 and RI2-2 should be closed. ForTTYP = OFF, or 1PR, or 2PR repeat the test. RI2-1and RI2-2 should be open.

1.1.5 Zone 1 Test/Phase-To-Phase

Step 13. Two methods can be used for this test.

3023--- 4.5( )ej85 1

3--- 4.5( ) 3( )ej40+

------------------------------------------------------------------

303 85( )+ j 3 sin (85) + 4.5 cos (40) + j4.5 sin (40)cos-----------------------------------------------------------------------------------------------------------------------------

4.31 57.76–( )∠

306.96 57.76 x–( )cos-----------------------------------------------

IVLN

Z1P PANG X–( )cos-------------------------------------------------- = 6.67A 5%±=

a. Using T-connection (with Doble or Multi-AmpTest Unit; refer to Figure A-3 for external termi-nal connection and configuration 1.

• VA = 1/2 VF @ 0°

• VB = 1/2 VF @ 180°

• VC = 3/2 (70) = 105V @ 90° lead

Using VF = VA-VB = 30V

• VA = 15V @ 0°

• VB = 15V @ 180°

BC CA

VAN = 105 ∠90° VAN = 15 ∠180°VBN = 15 ∠0° VBN = 105 ∠90°VCN = 15 ∠180° VCN = 15 ∠0°IF = 3.33 ∠-75° IF = 3.33 ∠−75°

The following table is for BC and CA fault tests whenthe T-connection is used:

NOTE: Current (I A) required to trip = 3.33A ± 5%,with an angle of -75 degrees.

b. Using Y-connection

NOTE: This test is actually for φφG testing (seeFigure A-3, configuration 1).

VAN = VF

VBN = VF

VCN =

or

VAN = 17.3

VBN = 17.3

VCN = 96.4

For either T or Y connection, using a value of x = 75°(lagging), current required to trip:

12--- 2

3------- 0°∠

12--- 2

3------- 120°–∠

32--- 70 VAN

2 12---VF

2––×

120°∠

0°∠

120°–∠

120°∠

I.L. 40-385.5

A-4

From Table A-1:

• Z1P = 4.5 Ω

• PANG = 75°For Y-connection only, current (IA) required to trip =3.33A ±5%, with an angle of -45°, because Ian hasalready lagged VF (Vab) by 30°. Review all targets.

NOTE: The accuracy of the voltage reading in themetering mode is between 1 and 77Vrms. The inaccurate reading on V CN

will not affect the results of the test.

The reclose contacts (RI2-1 and RI2-2) should beclosed for setting of TTYP = 2PR or 3PR, and shouldbe open for TTYP = OFF or 1PR.

Step 14. Repeat Step 13 for both BC and CA faults.Use the following voltages for each fault type:

BC CA

V V

V V

V V

1.1.6 Zone 2 Tests

Step 15. Press the DISPLAY SELECT pushbuttonuntil the SETTINGS mode LED is displayed.Change the setting values to:

• Z1P = “OUT” (Zone 1 phase value)

• Z1G = “OUT” (Zone 1 ground distance)

• Z2P = 4.5 Ω (Zone 2 phase value)

• T2P = 1.0 sec (Zone 2 phase timer)

• Z2G = 4.5 Ω (Zone 2 ground value)

• T2G = 1.5 sec (Zone 2 ground timer)

• Z2RI = “YES” (Zone 2 reclosing)

• TTYP = “3PR” (Reclosing mode)

Step 16. Perform Steps 10 thru 14 (above) forZone 2 only, using delayed trip times accordingto the zone 2 phase timer (T2P), and the Zone 2ground timer (T2G). Tolerances for T2P and T2G

IVF

2Z1P PANG X–( )cos-------------------------------------------------------=

VAN 96.4 120°∠= VAN 17.3 120°–∠=

VBN 17.3 0°∠= VBN 96.4 120°∠=

VCN 17.3 120°–∠= VCN 17.3 0°∠=

F 3.33 45°–∠= F 3.33 45°–∠=

are 5% for an input current that is 10% above thecalculated value.

Repeat Step 10. The RI2 contacts 1 and 2should be closed, and the RB contacts 1 and 2should be open. Reset Z2RI to “NO”.

Repeat Step 10 again. The RI2 contacts 1 and 2should be open and the RB contacts 1 and 2should be closed.

Change the settings of T2G and T2P to BLK.Zone 2 should not be tripped for any type of fault.

1.1.7 Zone 3 Tests

Step 17. Press the DISPLAY SELECT pushbuttonuntil the SETTINGS mode LED is displayed.Change the setting values to:

• Z2P = “OUT” (Zone 2 phase value)

• Z2G = “OUT” (Zone 2 ground distance)

• Z3P = 4.5 Ω (Zone 3 phase value)

• T3P = 2.0 sec (Zone 3 phase timer)

• Z3G = 4.5 Ω (Zone 3 ground value)

• T3G = 2.5 sec (Zone 3 ground timer)

• Z3FR = “FWD” (Zone 3 direction)

• Z3RI = “YES” (RI = Z3T)

• TTYP = “3PR” (Reclosing Mode)

Step 18. Perform preceding steps 10 thru 14 forZone 3 only, using delayed trip times accordingto the Zone 3 phase timer (T3P), and the Zone 3ground timer (T3G). Tolerances for T3P and T3Gare ± 5% for an input current that is 10% abovethe calculated value.

Repeat Step 10. The RI2 contacts 1 and 2should be closed, and the RB contacts 1 and 2should be open. Reset Z3RI to “NO”.

Repeat Step 10 again. The RI2 contacts 1 and 2should be open and the RB contacts 1 and 2should be closed.

Step 19. Set Z3FR = REV, then repeat Step 10, ex-cept apply AG reversed fault (i.e., Ia leads Van by105°). The relay should trip, at Ia = 4.2A, in 2.5seconds. Reset Z3FR to “FWD”.

NOTE: For customers who use a computer totest the relays, or use their own settingsfor maintenance, refer to the following

I.L. 40-385.5

A-5

should be 6.0A, 4.5A and 3.0A, respectively.

1.1.8 Instantaneous Overcurrent (High-SetTrip)

Step 20. Using the SETTINGS mode, change thefollowing settings:

ITP = 10A LOPB = “NO”

ITG = 5A Z3G = “OUT”

Z3P = “OUT”

NOTE: The High-Set ground overcurrent (ITG)and phase overcurrent (ITP) are super-vised by Forward Directional Groundunit (FDOG) and Forward DirectionalPhase unit (FDOP), respectively. In or-der to test the High-Set trip, the 3 φvoltages are necessary as directionalreference. The ITG and ITP will automat-ically become non-directional over-current units if the setting of LOPB isYES and at least one input voltage iszero volts (e.g., LOPB = YES in the me-tering mode).

Step 21. Using Figure A-1, configuration #1, toconnect currents and voltages, apply AG fault asshown in Step 1.1.3. The MDAR should trip at Ia= 5 Amps ± 5 % with a target of ITG-AG. For re-versed fault, apply 8A reversed fault current (i.e.,Ia leads Van by 135° for Y-connection, or 105° for

T-connection). The relay should not trip.

Step 22. Using Figure A-3, to connect currents andvoltages, apply AB fault as shown in Step 1.1.5.The MDAR should trip at Iab = 10 Amps ±5%,with a target of ITP - AB. Apply a 15A reversedfault current (i.e., Ia leads Vab by 135° for Y-con-nection or 105° for T-connection). The relayshould not trip.

1.1.9 Ground Backup (GB) Test

Step 23. Use the SETTINGS mode and change thefollowing settings:

• ITP = “OUT”

• ITG = “OUT”

• GBCV = CO-8

• GBPU = .5

• GDIR = “NO”

example to calculate and determine tripcurrents; set the relay as follows:

Z1P = ZIG = 4.5 T1 = 0

Z2P = Z2G = 6.0 T2P = T2G = 0.2

Z3P = Z3G = 9.0 T3P = T3G = 0.3

PANG = GANG = 75ο ZR = 3

a. Single-Phase-to-Ground Fault

Use the equation in Step 10, and the following inputvoltages:

The single-phase trip currents for Zone 1, Zone 2,and Zone 3 at the maximum torque angle

are 6.0A, 4.5A and 3.0A, respectively.

b. Phase-to-Phase Fault

Use the T-connection and the equation in step 13.Apply the following input voltages:

The single-phase trip currents for Zone 1, Zone 2and Zone 3 at the maximum torque angle

are 4A, 3A and 2A, respectively.

c. Three-Phase Fault

Use the equation in Step 12 with the following inputvoltages:

The three-phase trip currents for Zone 1, Zone 2 andZone 3 at the maximum torque angles

VAN 45 0°∠ VLN= =

VBN 70 120°–∠=

VCN 70 120°∠=

I A 75°∠( )

VAN 18 0°∠ 12---VF= =

VBN 18 180°–∠ 12---VF= =

VCN 105 90°∠=

I AB 75°–∠( )

VAN 27 0°∠ VLN= =

VBN 27 120°–∠=

VCN 27 120°∠=

I A 75°, I B 195°, I C +45°∠–∠–∠

I.L. 40-385.5

A-6

• GTC = 24

NOTE: The note in Step 20 applies to the GBtest. The GB can be set to directionalground overcurrent. For loss-of-poten-tial condition, GB will be converted tonon-directional, automatically, regard-less of the GDIR=YES setting.

Using Figure A-1, apply A-G fault of 4.1A to MDAR.Trip time is determined as follows:

(TMSEC) =

where

(3IOF is zero sequence fault current.)

(TMSEC) =

TMSEC = 1073 msec

= 1.073 sec ± 5 % to trip

For values of 3I0 between 1.0 and 1.5, the following

equation would apply:

(TMSEC) =

The following equation can be used to calculate thetrip time for all CO curves from CO-2 to CO-11:

T(sec) =

T(sec) =

where

GBPU = Pickup current setting (0.5 to 4.0A).

GTC = Time curve dial setting (1 to 63).

To, K, C, P and R are constants, and are shown inTable A-2.

Step 24. For a Zero Sequence Directional unit (DI-RU = ZSEQ), the tripping direction of MDAR is:the angle of 3I0 leads 3V0 between +30° and

+210°. Change the setting of GDIR to “YES”. Ap-ply AG fault as shown in preceding Step 10, Fig-ure A-1. The relay should trip at the followingangles:

• +28°• -60° (± 88°)• -148°

The relay should not trip at the angles of:

• +32°• +120° (± 88°)• -152°

For a Negative Sequence Directional Unit (DIRU =NSEQ), the tripping direction of MDAR is: I2leads V2 by a value between +8° and +188°. Therelay should trip at the following angles:

• +3°• -82° (± 85°)• -167°

The relay should not trip at the angles of:

• +13°• +98° (± 85°)• +183°

Step 25. For a dual polarizing ground directionalunit (DIRU = DUAL) test, connect the test circuit

shown in Figure A -4; apply Lp 1.0A toterminals 12 (+) and 11(-), and apply a balanced3-phase voltage (70V) to Va, Vb, Vc, and Vn. Ap-

ply Ia = 4A to terminals 6(+) and 5(-).

NOTE: In order to eliminate the voltage polariz-ing effect, make sure the voltages arefinely balanced so that 3V0 is less than3.0 volt. If it is impossible to obtain3V0 < 3V, set Va = Vb = Vc = 0for the following tests.

The relay should trip at the following angles:

• -3°• -90° ( ± 87°)• -177°

The relay should not trip at the following angles:

• +3°

478 41223I 0 1.27–------------------------+

GTC24

------------

3I 0

3I OF

GBPU-----------------=

478 41224.1/0.5 -1.27------------------------------+

2424------

9200( )3I 0 1–----------------- GTC

24------------× CO 8 only–( )

T0K

3I 0 C–( )p--------------------------+

GTC24 000,------------------ for 3I 0 1.5≥(×

RI 0 1– )

------------------ GTC24 000,------------------× for 1 3I 0 1.5< <(

3I 0

3I OF

GBPU-----------------=

90°–∠

I.L. 40-385.5

A-7

• +90°( ±87°)• +177°

1.1.10 CIF, IOM, IL and LV Tests

Step 26. Set the relay per Table A-1. Change thefollowing settings: IOM = 3, IL = 2, CIF = YES,and connect a rated dc voltage to 52b, betweenTB5/3 (+) and TB5/4 (-). Apply an AG fault asshown in Step 10 (Figure A-1). The relay shouldtrip at Ia = 2A (IL) with CIF target.

Step 27. Change IL setting from 2 to 3.5A and re-peat the test shown in Step 26. The relay shouldtrip at Ia = 3A (IOM) with CIF target.

Step 28. LV setting test. Set LV = 60 and with IAN =4A, apply AG fault as shown in Step 10. The CIFtrip should be for VAN <60 Vrms ± 5%. Discon-nect the voltage from 52b and reset IOM = IL = 0.5

and CIF = NO.

1.1.11 Loss-of-Potential (LOP) Test

Step 29. For Load Loss Trip (LLT), set:

LLT = Yes

Z2P = Z2G = 4.5 ohms

T2P = T2G = 2.99 sec (or BLK)

Apply:

Va = 30

Vb = 70

Vc = 70

Ia = 3.5

Ib = 1

Ic = 1

Suddenly increase Ia from 3.5 to 4.5A and then turnIb OFF immediately. The relay should trip with LLT

target. The trip is accelerated due to the pickup ofZone 2 and the setting of LLT = YES.

Reset: LLT = NO

Z2P = Z2G = OUT

T2P = T2G = BLK

Step 30. Disconnect all current inputs. Connect 3balanced voltages of 70 Vac to Van, Vbn, and Vcn.Using the SETTINGS mode, change the setting:LOPB = YES.

NOTE: The “RELAY IN SERVICE” LED will notbe turned “OFF” for the condition of set-ting LOPB = Yes, but Zone 1, 2, 3 and pi-lot distance units will be blocked and allovercurrent units (GB, ITP, and ITG) willbe converted to non-directional opera-tion.

LOPB will be set if the following logic is satisfied:

• one (or more) input voltages (VAN, VBN orVCN) are detected (as <7 Vrms) without ∆Ichange, or

• a 3Vo (> 7Vrms) is detected with 3Io <Ios• Apply VAN, VBN and VCN rated voltage to

MDAR. Scroll the LED to metering mode; thedisplay shows LOPB = NO. Reduce VAN to62 Vrms (e.g., 3V0 = 8V). After approximate-ly 0.5 seconds, the display shows LOPB =YES and the form C failure alarm (AL1) con-tact is also deenergized.

Step 31. Set the relay as follows:

Z1P = 4.5 GBCV = CO-8

Z1G = 4.5 GBPU = 0.5

ITP = 10 GDIR = YES

ITG = 5 GTC = 24

Repeat Step 10 (AG Fault) with IAN = 4.5A. Whilein the metering mode, be sure that LOPB = YESbefore the fault current is applied. The relayshould be tripped with a target of GB. Apply 5.5A;the relay should be tripped with a target of ITG.Repeat the test with a reversed AG Fault; the re-lay will trip. Reset LOPB = NO; the relay shouldnot trip for the reversed fault. Set LOPB = YES.

Step 32. Apply a balanced three-phase voltage (70Vrms) and current (3A). Turn off Va; the relayshould not trip. Reset LOPB to NO.

1.1.12 Loss-Of-Current (LOI) Test

Step 33. Set LOIB to YES and IOM = 1.0A. Apply a

balanced three-phase voltage (70 Vrms). Con-nect the current inputs per Figure A-1, and applya single phase current of 1.1A to IA. After approx-

0°∠

120°–∠

120°∠

75°–∠

120°–∠

+120°∠

I.L. 40-385.5

A-8

imately 0.10 seconds, the “Relay In Service” LEDwill be turned off, and the GS (AL3) contactshould be closed.

Step 34. Increase IA to 1.5A. Depress the DIS-

PLAY SELECT pushbutton and change to themetering (VOLTS/AMPS/ANGLE) mode. PressFUNCTION RAISE pushbutton until the LOI dis-play is shown. The value should indicate “YES”.Suddenly turn OFF VA voltage; the relay should

not be tripped within 500 ms. It may operate after500 ms if a delta I is detected by the relay.Change the setting of LOIB from YES to NO.

1.1.13 Output Contact Test

Step 35. The purpose of this test is to check thehardware connections and relay contacts. It isdesigned for a bench test only. Remove JMP12(spare on the Microprocessor PC Board) andplace it in the JMP5 position. Open the red-han-dled FT switch (Trip and Breaker Failure Initiate)in order to avoid the undesired trip.

NOTE: The red-handled FT switch (#13) con-trols the dc supply of BFI, RI2 and theoptional RI1 relays. In order to test theserelays in the system, the external wiringshould be disconnected to avoid undes-ired reclosing or trip. For relays withoutFT switches, do not perform the OutputContact tests using the relay system.

Change the LED mode to “TEST” and select thetripping function field and the desired contact inthe value field. Push the ENTER button; the EN-TER LED should be “ON”. The corresponding re-lay should operate when the ENTER button ispressed. The following contacts can be tested:

• TRIP

• BFI

• RI1 (optional)

• RI2

• RB

• AL1 (with three balanced voltages applied)

• AL2

• GS

• SEND

• STOP

Remove JMP5 and replace it on JMP12.

Step 36. This completes the basic AcceptanceTest for the MDAR Non-Pilot system. (See sub-sequent segment for optional Single Pole Tripand Out-of-Step Block tests.)

1.2 PILOT PERFORMANCE TESTS

To prepare the MDAR relay assembly for Pilot Ac-ceptance Tests, connect the MDAR per Figure A-1,Configuration 1.

NOTE: For Power Supply module sub 13 orhigher, three Reed relays are used to re-place the mercury relays for GS, CarrierSTOP and SEND. Check jumpers JMP1(STOP) and JMP2 (SEND) for NO or NCoutput contact selection.

1.2.1 Front Panel Check

Step 1. Repeat steps 1 thru 6 in Non-Pilot Accep-tance Tests.

Step 2. Change the value settings, in Table A-1,as follows:

• PLT YES • PLTP 6.0

• Z3FR REV • Z3P 6.0

• ZIP OUT • Z3G 6.0

• ZIG OUT • T3P BLK

• PLTG 6.0 • T3G BLK

NOTE: When the dc voltage is applied to TB5terminals, check jumper position on In-terconnect module for the appropriateselection.

Connect a rated dc voltage to PLT/ENA terminalsTB5/9(+) and TB5/10(-).

1.2.2 Blocking (BLK) Scheme

Step 3. Change the STYP setting to BLK. Apply arated dc voltage to RCVR #1 terminals TB5/7(+)and TB5/8(-). Check the metering mode for RX1= YES. Apply an AG fault as shown in Step 10 ofthe Non-Pilot Acceptance Test (i.e., Va = 30 voltsand Ia = 4 Amps). The trip A contacts should notbe closed. The CARRY SEND should be “open”and the CARRY STOP should be “closed”.

Step 4. Remove the dc voltage from RCVR #1and apply AG fault. Trip A contacts should be“closed” and the target should show “PLTG AG”.

I.L. 40-385.5

A-9

Change the LED mode to “TEST” and select the“RS1” function. Push the ENTER button; the EN-TER LED should be “ON”. Repeat Step 4 with theENTER button depressed. The relay should nottrip.

Step 5. Apply AG reversed fault (i.e., Ia leads Va

by 105 degrees). The CARRY SEND contactsshould be “closed” and the CARRY STOPcontacts should be “open”. (Ia should be > 3A forthe Zone 3 setting of 6 ohms.)

Step 6. Change the LED mode to TEST and se-lect the function “TK”. Push the ENTER button;the ENTER LED should be “ON” and the CARRYSEND contacts should be closed.

Step 7. In order to determine setting accuracy (6ohms), the forward directional ground unit mustbe disabled. Set FDGT = BLK. Repeat precedingStep 4 of the Pilot Acceptance Test, with a trip in-put current (Ia) of 3 Amps (± 5%).

Step 8. Set the Forward Directional Ground Timer(FDGT) from 0 to 15 cycles. Repeat Step 4 withIa = 1.5 A. The relay should be tripped after the

delay time of FDGT.

NOTE: The FDOG trip is determined by the IOMsetting. It trips if 3I 0 >IOM and the forwardground directional unit picks up.

Step 9. In order to perform the Breaker FailureReclose Block Test, change the setting of FDGT= 0 and BFRB = NO. Repeat test Step 4; RB con-tacts (TB3/1 and TB3/2) should not close.Change BFRB to YES and repeat the test. TheRB contacts should be closed with a time delaybetween 150 ms and 200 ms.

1.2.3 PUTT or POTT Schemes

Step 10. Change the setting to STYP = PUTT (forunderreach scheme) or STYP = POTT (for over-reach scheme). In order to determine setting ac-curacy (6 ohms), the forward directional groundunit must be disabled. Set FDGT = BLK. Apply arated voltage to RCVR #1 terminals TB5/7(+) andTB5/8(-), and apply an AG fault as shown in Step10 of the Non-Pilot Acceptance Test. The tripcontact A should be closed at the input Ia = 3A(± 5%); the target should show “PLTG AG”, and

the CARRY SEND contact should be “closed” forPOTT setting. Do not test carry STOP for POTTand PUTT schemes.

Step 11. Apply a reversed AG fault (Ia leads Va by

105°). The relay should not trip, and the CARRYSEND contact should stay “open”.

Step 12. Remove the voltage on RCVR #1. Apply aforward AG fault as shown in Step 10. The tripcontacts should remain “open” for Ia = 5A.

Step 13. Change the LED mode to TEST and se-lect the function “RS1”. Push the ENTER button;the ENTER LED should be “ON”. Repeat Step 12with the ENTER button depressed. The relayshould trip.

Step 14. Repeat steps 8 and 9 for FDGT and BFRBtests, by using Step 10 with Ia = 1.5 A.

1.2.4 Weakfeed Scheme

Step 15. This function is for POTT only. In additionto the setting changes in Step 2, change the fol-lowing settings:

• STYP POTT

• WFEN YES

• Z3G 4.5

• Z3P 4.5

• Z3FR REV

Apply a rated voltage to PLT/ENA terminals TB5/9(+) and TB5/10(-), also RCVR #1 terminals TB5/7(+) and TB5/8(-).

With Van = Vbn = Vcn = 70 Vrms applied (asshown in Figure A-1), the relay should operatenormally.

NOTE: Do not apply fault current.

Turn Van “OFF”; the relay should trip with a target

of WFT, and the Carrier Send contact (TB4-1 andTB4-2) should close momentarily.

Reduce Van from 70 Vrms to 69Vrms and applya reverse AG fault current of 5A (i.e., Ia leads Vanby 105 degrees). Turn Van “OFF”; the relay

should not trip, and the Carrier Send contact(TB4-1 and TB4-2) should stay open.

I.L. 40-385.5

A-10

Step 16. This completes the basic AcceptanceTest for the MDAR Pilot System. (See subse-quent segments for optional Single Pole Triptest.)

1.3 SINGLE POLE TRIP (OPTION)ACCEPTANCE TESTS

Step 1. Set relay per Table A-1. Check the 62Tsetting; it should be 5.000. For a Pilot System,change the setting to PLT = YES, and apply a rat-ed dc voltage to Pilot Enable terminals TB5/9(+)and TB5/10(-). Also apply a rated voltage toRCVR #1 terminals TB5/7(+) and TB5/8(-) if theSTYP = POTT or PUTT; set TTYP = SPR.

Apply AG fault as shown in this Appendix Section1.1.3, Step 10. The Trip A contacts (2FT-14/1-2and 3-4) should be closed. Repeat BG fault (forTrip B contact closures) and repeat CG-Fault (forTrip C contact closures).

1.3.1 Reclose (RI) Trip and Breaker Failure(BFI) Contacts

Step 2. Refer to the Non-Pilot Acceptance Testfor the single-phase-to-ground faults (Steps 10and 11), and to the three-phase fault (Step 12).The fault current should be 20% greater than thecalculated values for the tests in these steps. The“fault types” applied to the MDAR relay areshown in Table A-3 (column 2). TTYP settingsare shown in column 1, whereas the results of RI,Trip, and BFI contacts are shown in columns 3, 4,and 5, respectively.

1.3.2 62T Trip

Step 3. XTRIPA, XTRIPB and XTRIPC Termi-nals. MDAR’s 52a [TB5/1(+) & TB5/2(-)] is usedas XTRIPA input, SBP [TB5/13(+) & TB5/14(-)] isused as XTRIPB and RCVR2 [TB5/11(+) & TB5/12(-)] is used as XTRIPC.

(a) Set IM = 5 and SPTT = 6. Apply a rated dc volt-age to XTRIPA terminals. Apply an AG fault withIa = 4.5 amps and Va = 30 volts as shown in Ap-pendix Section 1.1.3, step 10. The relay shouldtrip in 5 seconds with a display of 62T.

(b) Repeat (a) but for XTRIPB terminals and BGfault.

(c) Repeat (a) but for XTRIPC terminals and CGfault.

1.3.3 SPTT Timer Test

Step 4. Set SPTT = 4. Repeat the test of step 3 (a)with voltage applied to XTRIPA. The relay shouldtrip with a target of Z1G-AG in 4 seconds. ResetSPTT = 1.

1.4 MDAR WITH OUT-OF-STEP BLOCKOPTION

Refer to Figure A-5. The RT setting (21BI) is for theinner blinder. The RU setting (21BO) is for the outerblinder. If the setting of OSB1 (for Z1P) or OSB2 (forZ2P) or OSBP (for PLTP) is “YES”, and the powerswing stays inside the two parallel lines (RT and RU)for more than 50 ms, the three-phase fault trip will beblocked for Zone-1 or Zone-2 or Pilot fault, respec-tively, until the timer (OSTM) times out.

Connect the test circuit as shown in Figure A-2.

1.4.1 Condition OSB1 = OSB2 = OSBP = NO

Step 1. Set the relay per Table A-1, except for thefollowing settings:

Z1P = 10

Z1G = 10 T2P = 0.8

Z2P = 20 T2G = 0.8

Z2G = 20 IM = 1.5

(Check: PANG = GANG = 75; RT = RU = 15; OSTM= 500)

Step 2. Adjust the inputs as follows:

Step 3. Apply current IF of 2.35A ±5% suddenly.

The relay should trip with a display of Z2P = ABC.

Step 4. Apply IF of 4.7A ± 5% suddenly. The relay

should trip with a display of Z1P = ABC.

NOTE: The trip current ( IF) can be obtained fromthe equation in test Step 12 (1.1.4 Zone 1Test/Three-Phase), with the parameters:

Va 40 0°∠= I a I F 45°–∠=

Vb 40 120°–∠= I b I F 165°–∠=

Vc 40 120°∠= I c I F 75°∠=

I.L. 40-385.5

A-11

VLN = 40 PANG = 75

Z1P = 10 (or Z2P = 20) X = 45

1.4.2 Condition OSB1 = OSB2 = OSBP = YES

Change the OSB setting from NO to YES and RT =4, RU = 8.

Step 1. Change the LED to metering mode withthe display of OSB = NO.

Step 2. Apply a current IF of 2.7A ± 5% suddenly.

The display should show OSB = YES. Thismeans the input power swing is inside the outerblinder (2IBO). Repeat this test for IF = 4A and

4.5A. The display should show OSB = YES be-cause the power swing is within two blinders(2IBO and 2IBI).

NOTE: The load restriction logic is not includedin this relay. the relay will trip after tim-ers (OSTM + T2P) time out, e.g., 1300 ms.

Step 3. Apply IF of 5.25A suddenly (5% above the

calculated value). The relay should trip with a dis-play Z1P = ABC. The trip time should be<2 cycles.

A computer controlled test unit is requiredfor the following test from step 4 to step 6

Step 4. OS and OSOT1 Timers (50/OSTM andOSTM/0).

(a) Use a computer to set the test sequence as fol-lows:

State #1 State #2 State #3

Va = 70 ∠0° Va = 40∠0° Va = 40 ∠0°

Vb = 70∠-120° Vb = 40∠-120° Vb = 40∠-120°

Vc = 70∠-120° Vc = 40∠-120° Vc = 40∠-120°

Ia = 1∠0° Ia = 3.5∠-45° Ia = 6∠-45°

Ib = 1∠-120° Ib = 3.5∠-165° Ib = 6∠-165°

Ic = 1∠120° Ic = 3.5∠75° Ic = 6∠75°

T1 = 50 cycles T2 = 4 cycles T3 = 36 cycles

T1, T2 and T3 are the duration time of state #1,#2 and #3, respectively. Set the timer start atstate #3. The relay should trip in 500 ms with atarget of Z1P – ABC.

(b) Change T3 from 36 cycles to 24 cycles. Repeatthe test. The relay should not trip.

(c) Change T2 from 4 cycles to 2 cycles. The relayshould trip in 2 cycles with a target of Z1P –ABC. Reset T2 = 4 and T3 = 36.

Step 5. Timer 200/OSTM Test. Change the set-ting of RT from 4 to 7.

(a) Set T2 = 10 cycle in State #2. Repeat the test4(a). The relay should trip in 2 cycles.

(b) Set T2 = 15 in State #2. Repeat the above test.The relay should trip in 500 ms with a target ofZ1P – ABC.

Step 6. OSOT2 Timer (OSTM/0).

(a) Change the test sequence by deleting the State#3 shown in Step 4. Change T2 = 100 cycles,and RT = 7. Set the timer start at State #2. Therelay should trip in 800 ms (T2P) with a target ofZ2P – ABC.

(b) Change RT = 4. Repeat the test. The relayshould trip in 1300 ms (OSTM + T2P) with a tar-get of Z2P – ABC.

I.L. 40-385.5

A-13

2. MAINTENANCE QUALIFICATION TESTS

Maintenance qualification tests will determine if aparticular MDAR unit is working correctly. Refer tothe WARNING note in Section A-1 before ener-gizing the relay.

2.1 Non-Pilot Maintenance Tests

It is recommended that either Doble or Multi-Amptest equipment should be used for this test. Refer toFigure A-1 for the input voltage and current terminalconnection per configuration 1. Refer to Table A-4for all jumper positions.

2.1.1 Front Panel and Metering Check

Step 1. Turn on rated dc voltage. Check theFREQ setting; it should match the line frequencyand ct type (CTYP). Apply a balanced 3-phasevoltage (70 Vac); the Alarm 1 relay should be en-ergized. (Terminal TB4/7 and TB4/8 should bezero ohms.) The “Relay-in-Service” LED shouldbe “ON”.

Step 2. Press RESET pushbutton; the green LED(Volts/Amps/Angle) should be “ON”. Press theFUNCTION RAISE or FUNCTION LOWER push-button. Read the input voltages and their angles:

VAG = 70 ∠0°VBG = 70 ∠−120°VCG = 70 ∠120°with an error of ± 1 volt and ± 2°.

Step 3. Press the DISPLAY SELECT pushbutton,and note that the mode LED cycles thru the fivedisplay modes. Release the pushbutton so thatthe SETTINGS mode LED is “ON”. Press theRAISE button to scroll thru the FUNCTIONFIELD to check the settings per Table A-1.Change the setting, if necessary, by depressingthe RAISE button in the VALUE FIELD to the de-sired value and then pressing the ENTER button.

Step 4. Press the RESET pushbutton (LED jumpsto Metering mode). Apply 3.0 A to IA with an angle

of -75°. Read IA from the front display; it should

be 3.0 ∠−75° with an error of 5% and ± 2°. Movethe input current from IA to IB or IC terminal.Read IB or IC to verify the transformer’s accuracy.

2.1.2 Impedance Accuracy Check

Step 5. Apply voltages to MDAR as follows:

VA = 30 ∠0°VB = 70 ∠-120°VC = 70 ∠120°

Apply forward fault current IA ∠-75° suddenly.

The relay should trip for IA = 4A ± 5%. The dis-

play should show “Z1G AG”.

Repeat for B and C phases per the following table:

Phase B Phase C

VA = 70 ∠0° VA = 70 ∠0°VB = 30 ∠-120° VB = 70 ∠-120°VC = 70 ∠120° VC = 30 ∠120°IB = 4 ∠-195° IC = 4 ∠45°

2.1.3 Input Opto-Coupler Check

Step 6. External ResetApply an AG fault as shown in Step 5. The LASTFAULT LED should be flashing. Press the frontRESET pushbutton. The green LED (Volts/Amps/Angle) should be “ON”. Press the DIS-PLAY SELECT pushbutton and move the LEDback to LAST FAULT. The fault information “Z1GAG” should be displayed again. Apply a rated dcvoltage to terminals TB5/5 (+) and TB5/6(-). Thetarget data should be erased and the displayshould show “FTYP”. Remove the external resetvoltage.

Step 7. 52b TerminalsChange the CIF setting from “NO” to “YES”.Apply an AG fault as shown in Step 5, with IA =

2 ∠−75°. The relay should not trip. Apply a rateddc voltage to terminals TB5/3 (+) and TB5/4 (-).Repeat the test. The relay should trip with a tar-get of CIF. Remove the 52b voltage and resetCIF to “NO”.

2.1.4 Input Transformer (I P) Check

Step 8. Change the settings from Table A-1 as fol-lows:

Appendix A-2. ACCEPTANCE/MAINTENANCE TESTS (V2.6X)

I.L. 40-385.5

A-14

ZIP = OUTZIG = OUTDIRU = DUALGBCV = CO-8GBPU = 0.5GDIR = YESGTC = 24

For a dual polarizing ground directional unit (DI-RU = DUAL) test, connect the test circuit shownin Figure A-4. Apply IP = 1.0A ∠−90° to terminals

12(+) and 11(-), and apply a zero volt to Va, Vb,

Vc, and Vn. Apply Ia = 4A to terminals 6 (+) and 5

(-). The relay should trip at the following angles:

• -3°• -90° (± 87°)• -177°

The relay should not trip at the following angles:

• +3°

• +90° (± 87°)• +177°

Change the settings back to Table A-1.

2.1.5 Output Contact Test

Step 10. The purpose of this test is to check thehardware connections and relay contacts. It isdesigned for a bench test only. Remove JMP12(spare on the Microprocessor PC Board) andplace it in the JMP 5 position.

Change the LED mode to “TEST” and select thetripping function field and the desired contact inthe value field. Push the ENTER button; theENTER LED should be “ON”. The correspondingrelay should operate when the ENTER button ispressed. The following contacts can be tested:

• TRIP

• BFI

• RI1 (optional)

• RI2

• RB

• AL1 (with 3 balanced voltages)

• AL2

• GS

• SEND (optional)

• STOP (optional)

Remove JMP 5 and place it on JMP12.

2.2 Pilot Maintenance Test

Connect the MDAR per Figure A-1, Configuration 1.

2.2.1 Basic Function Test

Step 1. Repeat Step 1 thru 10 in the Non-PilotMaintenance Test (2.1.1 thru 2.1.5).


Step 2. PLT ENA Terminals Change the following settings from Table A-1:

• PLT YES• Z1P 0UT• Z1G OUT• PLTP OUT• PLTG 6.0• Z3P OUT• Z3G 6.0• T3P BLK• T3G BLK• Z3FR REV

a. Block Systems OnlyChange the STYP setting to BLK. Apply a for-ward fault, as shown in the Non-Pilot Mainte-nance Test, step 5. The relay should not trip.

Apply a rated dc voltage to PLT ENA terminalsTB 5/9(+) and TB 5/10(-). Repeat the test. Therelay should trip.

b. POTT/PUTT Systems OnlyChange the STYP setting to POTT. Change theLED mode to TEST and select the function“RS1”. Push the ENTER button; the LED shouldbe “ON”. Apply a forward fault as shown inNon-Pilot Maintenance test, Step 5. With theENTER button depressed, the relay should nottrip. Apply a rated dc voltage to terminals TB 5/9(+) and TB 5/10(-). Repeat the test. The relayshould trip.

Step 3. Receiver 1Apply a dc voltage to PLT ENA terminals TB 5/9(+) and TB5/10(-).

a. Block Systems OnlyChange the STYP setting to BLK. Apply a for-ward fault as shown in the Non-Pilot Mainte-nance test, Step 5. The relay should trip.

I.L. 40-385.5

A-15

Apply a rated dc voltage to RCVR #1 terminalsTB 5/7 (+) and TB 5/8(-). Repeat the test. The re-lay should not trip.

b. POTT/PUTT Systems OnlyChange the STYP setting to POTT. Apply a for-ward fault as shown in the Non-Pilot Mainte-nance test, Step 5. The relay should not trip.Apply a rated dc voltage to RCVR #1 terminalsTB 5/7(+) and TB 5/8(-). Repeat the test. The re-lay should trip.

2.3 Single-Pole Trip Test

2.3.1 Output Contact Test (Phases B and C)

Step 1. Set relay for Non-Pilot systems (Table A-1) or for Pilot systems per Section 2.2.2. Checkthe 62T setting; it should be 5.000.

For a Pilot system, change the PLT setting toYES, and apply rated dc voltage to Pilot enableterminals TB 5/9(+) and TB 5/10(-). Also, apply arated voltage to RCVR #1 terminals TB 5/7(+)and TB 5/8(-) if the STYP = POTT or PUTT; setTTYP = SPR.

Step 2. Repeat Non-Pilot Maintenance test, step5 for trip and BFI. Check the contact closures forTrip A, &BFIA (AG fault), Trip B & BFIB (BG fault)and Trip C & BFIC (CG fault).


NOTE: Before applying any voltages, check thejumper positions on the Interconnectmodule. The JMP7 and JMP9 should be“IN” for the XTRIPB application.

Step 3. XTRIPA Terminals.

(a) Set IM = 5 and SPTT = 6. Apply a rated dc volt-age to XTRIPA terminals TB5/1(+) and TB5/2(-).Apply an AG fault with Ia = 4.5 amps andVa = 30 volts as shown in the test step 5 of theNon-Pilot Maintenance Test. The relay shouldtrip in 5 seconds with a display of 62T.

(b) Change the setting of IM from 5 to 2. Repeat thetest 3(a). The relay should trip in 4 cycles with adisplay of CIF.

Step 4. XTRIPB Terminals.Set IM = 5. Apply arated voltage to XTRIPB terminals TB5/13(+) andTB5/14(-). Repeat step 3(a) except apply a BGfault.

Step 5. XTRIPC Terminals. Repeat step 3(a) ex-cept apply a voltage to XTRIPC terminals TB5/11(+) and TB5/12(-) and apply a CG fault. ResetIM = 1 and SPTT = 1.

I.L. 40-385.5

A-16 Figure A-1 Test Connection for Single-Phase-to-Ground Faults (Sheet 1 of 4)

1502B51Sub 1

I.L. 40-385.5

A-17

Figure A-2 Test Connection for Three-Phase Faults

1502B51Sub 1

(Sheet 2 of 4)

I.L. 40-385.5

A-18 Figure A-3 Test Connection for Phase-to-Phase Faults

1502B51Sub 1

(Sheet 3 of 4)

I.L. 40-385.5

A-19

1502B51

Sub 1

(Sheet 4 of 4)Figure A-4 Test Connection for Dual Polarizing Ground Directional Unit

I.L. 40-385.5

A-20

9651A71Sub 1

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

-8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10 11 12 13 14

R

Z2 = 20 ∠−75˚

Z1 = 10 ∠−75˚

jX

RT RU

Z = 17.3 ∠ -45˚(I = 2.35 Amps)

ZU = 16 ∠-45˚(I = 2.5 Amps)

Z = 8.7∠-45˚(I = 4.7 Amps)

ZT = 8.7∠-45˚(I = 5.0 Amps)

4 OHMS

8 OHMS

INPUTS: Va = 40 ∠0˚, Vb = 40 ∠-120˚, Vc = 40 ∠120˚

SETTINGS: PANG = 75˚, GANG = 75˚, ZR = 3

ABC FAULT WITH FAULT ANGLE OF 45˚

75˚45˚

Figure A-5 MDAR with Out-of-Step Block Option

I.L. 40-385.5

A-21

TABLE A-1. PRESENT MDAR SETTINGS (PILOT SYSTEM) — V2.1x

VERS 0OSC TRIPFDAT TRIPCTR 1000VTR 2000FREQ 60CTYP 5RP NOXPUD .5DTYP KMTTYP OFF62T 5.000*SPTT 1.000Z1RI YESZ2RI NOZ3RI NOBFRB NOPLT NOSTYP 3ZNPFDGT 3WFEN NOBLKT 0PLTP OUTPLTG 6.00Z1P 4.5Z1G 4.5T1 0Z2P OUTT2P 1.00Z2G OUTT2G 1.50Z3P OUT

T3P 2.00Z3G OUTT3G 2.50Z3FR REVPANG 75GANG 75ZR 3.0LV 60IL .5IM 1.0IOS .5IOM 1.0ITP OUTITG OUTOSB1 NOOSB2 NOOSBP NOOSTM 500RT 15.00RU 15.00DIRU ZSEQGBCV OUTGBPU .5GTC 24GDIR YESCIF NOLLT NOLOPB NOLOIB NOAL2S NOSETR YESTIME NO

* For Single Pole Trip option only.

NOTE: This MDAR settings table is for 60 Hz and 5A ct systems. For 1A ct, change PLT, PLG, Z1P,Z1G, Z2P, Z2G, Z3P, Z3G, RT, RU by multiplying a factor of 5, and all current values men-tioned in the text should be multiplied by a factor of 0.02.

Curve # T0 K C P R

CO2 111.99 735.00 0.675 1 501CO5 8196.67 13768.94 1.13 1 22705CO6 784.52 671.01 1.19 1 1475CO7 524.84 3120.56 0.08 1 2491CO8 477.84 4122.08 1.27 1 9200CO9 310.01 2756.06 1.35 1 9342

CO11 110. 17640.00 0.5 2 8875

TABLE A-2. TRIP TIME CONSTANTS FOR CO CURVES

I.L. 40-385.5

A-22

TABLE A-3. FAULT TYPES APPLIED TO MDAR

SETTING FAULT TYPE OUT CONTACTSTTYP APPLIED RI TRIP BFI

OFF AG NO A,B,C A,B,CBG NO A,B,C A,B,CCG NO A,B,C A,B,CABC NO A,B,C A,B,C

1PR AG RI2 A,B,C A,B,CAB NO A,B,C A,B,CABC NO A,B,C A,B,C

2PR AG RI2 A,B,C A,B,CAB RI2 A,B,C A,B,CABC NO A,B,C A,B,C

3PR AG RI2 A,B,C A,B,CBG RI2 A,B,C A,B,CCG RI2 A,B,C A,B,CAB RI2 A,B,C A,B,CABC RI2 A,B,C A,B,C

SPR AG RI1 A ABG RI1 B BCG RI1 C CABC NO A,B,C A,B,C

SR3R AG RI1 A ABG RI1 B BCG RI1 C CABC RI2 A,B,C A,B,C

I.L. 40-385.5

A-23

TABLE A-4. RECOMMENDED JUMPER POSITIONS (V2.6X)

OUTER CHASSIS

An External jumper between FT-Switch 13 and 14 of 2FT-14 should be connected permanently.(Refer to terminals 2 & 4 of 2 FT-14 on Figure 5.)

INTERCONNECT Module

JMP 1 to 6, & 13 For the rated input dc voltageJMP 7 & 9 For Single Pole Trip Application (XTRIPB)JMP 8 & 10 For the trip alarm (AL2-2)JMP 11 & 12 For MDAR with FT switches only

MICROPROCESSOR Module

JUMPER POSITION FUNCTION

JMP 1 1-2 EEPROM (8kx8)JMP 2 2-3 Single-pole trip optionJMP 2 1-2 Three pole tripJMP 3 OUT Standard for Rotation ABCJMP 4 OUT No dropout time delay for trip contactsJMP 5 OUT Disable output contact testJMP 6 OUT Normal operationJMP 8 & 9 1-2 RAM (32kx8)JMP 10, 11 & 12 IN/OUT Spare jumpers

POWER SUPPLY Module

JMP1 1-2 Carrier Stop NO2-3 Carrier Stop NC

JMP2 1-2 Carrier Send NO2-3 Carrier Send NC

I.L. 40-385.5

A-25

I.L. 40-385.5

A-25

I.L. 40-385.5

A-25

Figure 3 MDAR (REL-300) Relay Assembly

Figure 4 MDAR (REL-300) Display Panel

sub 22403F38

sub 69651A07

I.L. 40-385.5

A-26

I.L. 40-385.5

A-26

I.L. 40-385.5

A-26 Figure 5 MDAR (REL-300) Relay Assembly

sub 31502B21

I.L. 40-385.5

A-27

I.L. 40-385.5

A-27

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A-27

Figure 6 MDAR (REL-300) Relay Backplane Board Terminals

sub 11615C70

I.L. 40-385.5

A-28

I.L. 40-385.5

A-28

I.L. 40-385.5

A-28Figure 7 Overall Flowchart for Microprocessor Software in MDAR (REL-300) Relay

POWERON

- Initialization- Self-Checks

Mode =Background

START

Sample V and I

dc OffsetCorrection

Compute V and IPhasors Using

fourier Algorithm

Mode?

Background

Disturbancein ∆V or ∆I?

− Operate Panel Interface- Hardware Self-Checks

Fault

Mode =Fault

Relaying CalculationsZone 1 and Pilot Zone

Pilot Logic andChannel Control

Y

N Mode =Background

No Fault for3 Cycles?

Y

N

Relaying Calculations

- Zone 2- Zone 3- Out-of-Step Blinders- Inst. Overcurrent- Ground Backup- Phase Selector

Checks and Logic

- Non-Pilot Trip Logic- Loss-of-Potential and Loss of Current- Data Communications- Contact Inputs

sub 29654A12

I.L. 40-385.5

A-31

I.L. 40-385.5

A-31

I.L. 40-385.5

A-31 A

Figure 12 Loss-of-Potential Logic

B

XF

A B

No Load Current

RY RY

S

C

XF2

A B

RY RY

S S

XF1

50%

sub 39655A82

I.L. 40-385.5

A-33

I.L. 40-385.5

A-33

I.L. 40-385.5

A-33

Figure 15. MDAR (REL-300) Zone-1 Trip Logic

sub 19659A66

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A-34

I.L. 40-385.5

A-34

I.L. 40-385.5

A-34


sub 19659A67

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A-35

I.L. 40-385.5

A-35

I.L. 40-385.5

A-35


sub 11504B04

I.L. 40-385.5

A-36

I.L. 40-385.5

A-36

I.L. 40-385.5

A-36

Figure 18 MDAR (REL-300) Highset Trip Logic

Figure 19 MDAR (REL-300) Close-into-Fault Trip

sub 29659A68

sub 29655A84

I.L. 40-385.5

A-37

I.L. 40-385.5

A-37

I.L. 40-385.5

A-37

Figure 20 MDAR (REL-300) Unequal-Pole Closing Load Pickup Control

sub 19658A87

Figure 21 MDAR (REL-300) Inverse Time Overcurrent Ground Backup Logic

sub 19655A81

I.L. 40-385.5

A-38

I.L. 40-385.5

A-38

I.L. 40-385.5

A-38

Figure 22 MDAR (REL-300) Zone-1 Extension Scheme

Figure Load-Loss Accelerated Trip Logic

sub 29656A33

sub 19654A16

I.L. 40-385.5

A-40

I.L. 40-385.5

A-40

I.L. 40-385.5

A-40 Figure 25 Load-Loss Accelerated Trip Logic

sub 21504B29

I.L. 40-385.5

A-41

I.L. 40-385.5

A-41

I.L. 40-385.5

A-41

Figure 26 Pilot Trip Relay

Figure 27 POTT/Unblocking, Pilot Trip Logic

sub 29659A70

sub 19659A69

I.L. 40-385.5

A-42

I.L. 40-385.5

A-42

I.L. 40-385.5

A-42

Figure 28 Carrier Keying/Receiving Logic in POTT/Unblocking Schemes

* sub 31504B30

I.L. 40-385.5

A-43

I.L. 40-385.5

A-43

I.L. 40-385.5

A-43

Figure 29 PUTT Scheme

Figure 30 Blocking System Logic

sub 11504B31

sub 19659A71

I.L. 40-385.5

A-45

I.L. 40-385.5

A-45

I.L. 40-385.5

A-45

Figure 34 FDOG Supplements PLTG for High Rg Faults

Figure 33 Weakfeed Application

sub 19659A72

* sub 29655A86

I.L. 40-385.5

A-46

I.L. 40-385.5

A-46

I.L. 40-385.5

A-46

Figure 35 Power Reversal

sub 19654A17

I.L. 40-385.5

A-47

I.L. 40-385.5

A-47

I.L. 40-385.5

A-47

Figure 36 Reverse-Block Logic

sub 19659A73

I.L. 40-385.5

A-48

I.L. 40-385.5

A-48

I.L. 40-385.5

A-48

Figure 37 Unequal-Pole Closing on Fault

sub 19654A29

I.L. 40-385.5

A-49

I.L. 40-385.5

A-49

I.L. 40-385.5

A-49

Figure 38 Simplified MDAR Version 2.60 SPT Logic

* sub 41504B32

I.L. 40-385.5

A-50

I.L. 40-385.5

A-50

I.L. 40-385.5

A-50

Figure 39 MDAR Block Diagram

sub 11611C12

Documents

dated November, 1995 REL-300 (MDAR) Relaying System Version 2 · REL-300 (MDAR) Relaying System Version 2.62 40-385.5 ABB Network Partner. Go to Table of Contents to easily access