Do You Remember Electromechanical Relays

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Do You Remember Electromechanical

Relays?

PPMVCoral Springs, FL

FT Switches and

EM Relays

FT Switch Product EvolutionThe Westinghouse Flexitest (FT) case was developedover 50 years ago to provide safe, reliable, in-case test capability for electromechanical relays

FT switch assemblies in the case provide a reliable means to insert or remove the internal relay assembly, providing secure circuit isolation

Individual blades may be opened to securely isolate trip circuits and safely short CT circuits

The relay may be removed from the case for bench testing, or remain in the case for testing with separate source, in service or current probe test plugs

FT Switch Product EvolutionThe flexibility provided by the FT case design evolved into a separate family of molded base test switches that provide a cost-effective means for isolation and testing of relays, meters and other electrical devices, and particularly for safely opening a current circuit in the proper sequence.

Standard switches are available in many combinations of potential, current or current shorting poles and special combinations are available on request

Standard FT-1 10 pole Switch

FT-14, 14 pole Switch

FT-1 with clear cover and colored handles

FT-1X and FT-14X Switch Configurations

Extended rear terminal 10 or 14 pole FT-1 Rear terminals of the switch are at the same depth as most 19” rack mounted relaysRated for 600 volts at 30 amps.Only 2U rack unit space requiredAvailable in any variety of rack unit height Customized paint, plating or material availableAllows equipment to be mounted directly above and below unit Option of 8.25, 10.25 or 12.25 inch depthsOther features same as standard FT-1 switches

10 pole Extended FT Switch

14 pole Extended FT Switch

FT-19R

The FT-19R assemblies can accommodate up to three FT-1 switches mounted on a 19” wide, 2 Rack Unit (2RU), 3RU, or 4RU steel or brushed aluminum mounting plate. Plate height, color, and switch configuration can be customized to users requirements. The Full Length Black, Individual Clear, and Individual Black covers are optional. All covers can be meter sealed.Standard FT Plug for all testing requirementsDescriptive Bulletin 41-078

Grey rolled steel panel 2U

Beige rolled steel panel 2U

Grey rolled steel panel 3U with labels

Black rolled steel panel 3U, switches located at the bottom

Brushed Aluminum flat panel

FT-1F, Front Connected FT Switch

Front Connected FT Switches have the smallest foot-print of ant 10 pole design in the market

Ideal for mounting inside panels, may be mounted to panel on Unistrut or DIN railsEither black or clear covers may be specifiedAny configuration that is available from a regular 10 pole FT switch may be specifiedAny available color switch handle may be specified

Descriptive Bulletin 41-079

FT-1 Web Based Configurator Tool

FT-1 Applications – Bus Differential Configuration

FT-1 Configuration

C-C C-C C-C C-C-C-A

IA IB IC IN



Aging Nuclear Power Plants

About 30 percent of our nation’s nuclear power plants have had equipment failures partly do to equipment having aged There are 103 nuclear power plants in the United States Nuclear power plants supply about 20 percent of our electricity Average life span is about 40 years Approximately 60 percent of the nuclear power plants in the US are greater than 20 years oldThe problem is getting worse as the equipment gets older If the equipment is not upgraded, eventually failures will adversely affect plant safety and performance

Upgrading Relays with Sensors

One of the big reasons people upgrade their EM substations to microprocessor relays is to gain communications to the relays and data acquisition.

Cost to upgrade is large and includes:Extensive engineering time

Cost of new relays

All new panels

Complete rewiring of substation

Real Estate may be limited

SE Intelligent Data Sensors -eight channel receiver and

Clamp- on Sensor

Testing Relays with Sensors



Actual Labor Cost Model

Quantity Item Cost1 Wiring Inside of Panel $8,000

24 conductor, #8 Cable for Voltage & Currents $1.95/ft/cable

212 Conductor Control Cable $2.50/ft each

200 HrsLabor for Terminations and Pulling Table $125/hr

• This does not include costs such as Asbestos and PCBremoval

• Total cost can exceed $30,000

Cand Pulling Cable

A New Attractive Low Cost Alternative

Clamp on Sensors to automate Electro-Mechanical substations

Small clamp on sensors provides an analog output of 0 to 5V which is proportional to the current flow through the wire.

Features include:Clamp-on AC/DC Sensor

Sensitive down to 10 microsecond resolutions

Single cable for Power & Output

Shielded Enclosure

Fits 12 AWG electric Wires

5% accuracy range

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2nd Harmonics under 12% for 2 cycles (minimum seen is 6%)

Plus, the magnitude is over 2 Amps RMS (enough to operate

the diff relay)

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The Benefits of ABB Electromechanical

Relays

Coral Springs, FL

By: Glenn Goldfarb

EM

The Benefits of Electromechanical Relays

EM Relays are still the backbone of present day power systems and can be used for backup protection even in new installations


Selectivity

The Electromechanical Relay is a Single Function Relay and originally know as the Silent Sentinel - It only responds for a fault condition.

The Silent Sentinel

The Benefits of Electromechanical RelaysReliability

Electromechanical Relays are not susceptible to Fast Transients, Oscillatory SWC, EMI, RFI, Impulse or any other noise induced in the power system.


Security

Electromechanical Relays are not susceptible to terrorists or computer hackers. No Password Needed!


Simplicity

Electromechanical Relays do not require Firmware or Software upgrades!

The Benefits of Electromechanical RelaysMinimal Documentation

No red tape or stacks of paperwork and drawings required to change relay types


Speed

EM Relays Trip in ½ to 1½ cycles –relays operate for the fault parameters

Microprocessor Relays Trip in 1 to 2 cycles - relays have to process fault parameters and make a decision before operating


You can See and HearElectromechanical Relays Operate

Cylinder and Polar Unit Contacts Close / Open Induction Disk Elements move clockwise and counterclockwise


No more burned modulesEM Relays do not have power supply modules to burn up!

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CO, CO (HI-LO) Presented By: Glenn Goldfarb

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CO (HI-LO) Overcurrent Relay

The CO Relay is a single phase non-directional time overcurrent device. It is used to sense current level above the setting and normally is used to trip a circuit breaker to clear faults. A wide range of characteristics permit applications involving coordination with fuses, reclosers, cold load pickup, motor starting, or essentially fixed time applications.

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Induction Unit

Need minimum current level to operate (pickup-value)

Inverse time characteristics (more current = less time to operate)

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Electromagnet

Torque developed in disc is derived from interaction of fluxes by the electromagnet with those from induced currents in the aluminum disc.

IF lag coil is open no torque is developed in disc.

Lag Coil

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Induction Disc

T=Ø1Ø2 SIN(Ø2-Ø1)

Disk is aluminum

Eddy currents are generated on the disc due to the magnetic flux from the electromagnet

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Spiral Spring

Spring conducts current to the moving contact

Adjusting the spring tension will change the minimum pickup value

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Disc

The shape of the disc, together with the spiral spring and the electromagnet design, provides a constant minimum operating current over the travel range.

The weight is to balance the disc.

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Electromagnet

Lag Coil

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Time Characteristics

The main factor to determine the time characteristics of the induction unit is the type of laminations used.

The permanent magnet will serve to adjust the operating time of the induction unit by dampening the disc (fine adjustment).

Magnetic plugs in the electromagnet control the degree of saturation (curve shape).

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CO Electromagnet Laminations

Different types of laminations are used to obtain the curve characteristics.

Laminations that saturate faster will create a slower relay.

CO-2 & CO-11 are the fastest and CO-5 & CO-7 are the slower.

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CO Typical Time Curve

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ICS (Indicating Contactor Switch)

Three main functions

Provide indication of the relay operation.

Provide a path for high tripping currents.

(Relay contacts normally not designed to carry heavy currents).

Provide a seal in action.

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ICS Unit

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IIT(Indicating Instantaneous Trip)

Very similar to ICS unit. Designed to operate under AC current.

Operates as an instantaneous overcurrent trip unit.

Adjustable core provides pickup adjustment.

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IIT Unit

Equipped with a Lag

Loop to smooth the force

variations due to the

alternating current input.

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CO Internal Schematic

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CO External Schematic

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Acceptance Test

Minimum Trip:With the time dial set at 6, apply tap value current plus 3%, the contact should leave the back stop. Then lower the current to minus 3% of the tap value and contact should return to the back stop. Operating time (with time dial at “6”)

**FOR 50 HZ RELAY USE .228 - .288***FOR 50 HZ RELAY USE .22 - .262

T E ST A

T E ST B

T E ST C

C U ST . SE T T IN G S

R elay T ype Iac X T ap

V alue

T im e (sec.)

Iac X T ap

V alue

T im e (sec.)

Iac X T ap

V alue

T im e (sec.)

T im e C urves

See C urve H I-LO C O 2 3 .553 - .587 20 .211 - .229*** - - 619584 H I-LO C O 5 2 36 .29 – 39 .31 10 13 .73 – 14.87 - - 418245 H I-LO C O 6 2 2 .374 – 2 .546 20 1 .148 – 1 .232 - - 418246 H I-LO C O 7 2 4 .14 – 4 .40 20 1 .08 – 1 .14 - - 418247 H I-LO C O 8 2 13 .08 – 13 .62 20 1 .09 – 1 .13 - - 418248 H I-LO C O 9 2 8 .69 – 9 .05 20 .635 - .665 - - 418249 H I-LO C O 11 2 10 .71 – 11 .83 20 .229 - .255** 1 .3 49.4 – 57 .6 Sub 2

288B 655

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Technical Information

Contacts close with current suddenly applied

Sec. 4. A Sec. 4. C Sec. 4. D

RangeTap

SettingPickupAmps *

TapSetting

Pickup Amps *

Tap Setting

Pickup Amps *

2 - 48 2 - 7 1.7 - 1.9 7 - 17 7 17 - 48 17

3 - 48 3 - 9 2.7 - 2.9 9 - 20 9 20 - 48 17

6 -144 6 - 20 5.1 - 5.7 20 - 50 20 50 - 144 50

The “IIT” units are calibrated between 85% and 95% of lower tap. Example 2 – 48 amps unit is adjusted between 1.7 and 1.9 amps. The “IIT” can be adjusted to any pickup within the range with just changing the tap screw and adjusting the core screw to the desired level.

“IIT” UNITS

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Technical Information

ICS UNITS

The most common settings for the “ICS” unit are 0.2 & 2.0 DC amps. To verify the pick-up, close the contact of the timing unit(CO unit) and apply the tap current to the proper terminals according with the internal schematic. The most common connection is terminals 10 and 1.

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CO Relay characteristics & Specifications

Time Overcurrent UnitGeneral: Non-Directional, Single PhaseFrequency: 60 HZ Minimum Trip Current: +/- 3 % Tap ValueOperating Time: Curve dependent(seven CO types available) Dielectric Strength: 2200 VAC for one second between all circuits and each circuit to the case with leakage current not exceeding 1 milliampereOption: Torque control

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ITH Relay Characteristics & Specifications

High Drop-out Instantaneous (ITH) Unit (Optional)General: AC operated and adjustable core screw

Drop-out to pick-up ratio of 90% over entire 2 to 1 pick-up rangeOperating range can be increased to a 4 to 1 ratio

Operating Time:At 200% of trip setting < one cycleAt 500% of trip setting one-half cycleAt 1000% of trip setting one-quarter cycle

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KD-10 andKD-11 Compensator Distance Relay

Presented By:Glenn Goldfarb

KD-10 and KD-11 Compensator Distance Relay

The type KD-10 relay is a polyphase compensator type relay which provides a single zone of phase protection for all three phases. It provides essentially instantaneous tripping for phase-to-phase faults, two-phase-to-ground faults, and three-phase faults within the reach setting and sensitivity level of the relay.

The type KD-11 relay, is similar to the KD-10 relay except that the characteristic impedance circle for the 3-phase unit includes the origin. This relay is usually applied as a carrier start relay in directional comparison blocking schemes but it may also be used for time delay tripping in non pilot distance relaying.

KD Relay

Application:Compensator distance relay that provides a single zone of phase protection for all three phases.

It provides tripping for phase to phase, two phase to ground and three phase faults within the reach setting and sensitivity level of the relay

KD Relay Construction

Cylinder Unit:Main function is to operate when the angle between two signal applied is within certain range.

Widely used as a directional unit and in impedance relays.


Cylinder Unit:T=KI1I2SIN(Ø1-Ø2)-KS

Where K and Ø are design constants.

Different combinations of input quantities can be used for different applications, system voltages or currents or network voltages.

Compensator:Designated as T

Current to Voltage air gap transformer.

Voltage side has a tap which divides the winding in two sections.

The output voltage angle can be changed by connecting a resistor across one of the voltage winding sections.


Compensator:


Phase-to-Phase Fault

Vf = Desired Fault VoltageVa = ½ Vf � 0°Vb = ½ Vf � 180°Vc = √3/2(120) or Vc = 104V�90° lead = 270° lag

1-2-3

V1-2 = V3-1 = V2-3 = 120V

25v 25v= 50v

104v

T - Connection

3 Phase Fault

KD Relay 3 Phase Voltage Input

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Operation:

KD Relay

KD Relay

Impedance Circle

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KD Relay External Schematic

KD Relay Equations needed for testing

MSTZ Setting ±

=1

•Impedance measured by 3 phase unit

L

LL

IVZr×

= −

3 Setting

LLL Z

VI3

−=

Relay Setting

Used to find required test current

•Impedance measured by 2 phase unit

L

LL

IVZr×

= −

2 Setting

LLL Z

VI×

= −

2Used to find required test current

Tests Connections

Basic Test Connections for Type KD-10 and KD-11 Relays

Settings Calculation

Relay reach is set on the tap plate. The tap markings are:

(Short reach) 0.23, 0.307, 0.383, 0.537, 0.690, 0.920, 1.23

(Med. Reach) 0.87, 1.16, 1.45, 20.03, 2.9, 40.06, 5.8

(Long reach) 1.5, 2.0, 2.5, 3.51, 5.0, 7.02, 10.0

T, TA, TB, and TC

.0, .03, .09, .06

M, MA, MC

1, 2, 3

S1, SA, and SC

(Values between taps)

Calculations for setting the KD-10 and KD-11 relays are straightforward andapply familiar principles. Assume a desired balance point which is 90 percent


Of the total length of line. The general formula for setting the ohms reach of the relay is:

Rc

Z = 0.9 Zpri ___ [Equ. 9]

RV

The terms used in this formula and hereafter are defined as follows:

Z = The desired ohmic reach of the relay in secondary ohms.

0.9 = The portion of the total line for which the relay is set.

RC, RV = Current and Voltage transformer ratio

Zpri = Ohms per phase of the total line section


The relay tap plate setting, Z, is set according to the following equation:

Z = ST [Equ. 10]

1 ± M

T = Compensator tap setting.

S = Auto-transformer primary tap setting.

+M = Auto-transformer secondary tap setting. (This is a per unit value and is determined by the sum of the values between the “L” and the “R” leads. The sign is positive when “L” is above “R” and acts to lower the Z setting. The sign is negative when “R” is above “L” and acts to raise the Z setting.)


Example 1Step 1Assume the desired reach, Z is 7.8 ohms at 75º.Step 2aIn Table II we find nearest value to 7.8 ohms 7.88 that is100 x 7.88 = 101 percent of the desired reach.

7.8Step 2bFrom Table II read off:

S = 2T = 4.06M = +.03


Example 1 (Cont.)and “L” lead should be connected over “R” lead, with “L” lead connected to “.03” tap and “R” lead to tap “0.”

Step 2c

Recheck settings.

ST 2 x 4.06 Z = = 7.88

1 ± M 1 + .03


KD Relay Characteristics & Specifications

General: Compensator DistanceFrequency: 60 HZ (50 HZ available as “Similar To” 60HZ)Ranges: .2 – 4.5, .75 – 21.2, and 1.3 – 36.6 OhmsCurrent Circuit Rating:10 A. continuous except for the 1.3 – 36.6

ohm range where forS = 1, T = 10 6 A. continuous S = 2, T = 10 8 A. continuous S = 3, T = 10 9 A. continuous S = 1, T = 7.02 7 A. continuous 240 A. / 1 sec.

Operating Speed: Phase-to-Phase Unit – current times compensator setting dependent (ref. curves)

Indicating Contactor Switch (ICS)

General: DC operated and suitable for DC control voltages up to and including 250V.

Range: 0.2 / 2.0 amps (tapped coil) Coil Resistance: 0.2 amp tap 6.5 ohms

2.0 amp tap 0.15 ohmContact Rating: 30 amperes at 250 volts dc and carry long

enough to trip a circuit breaker

Dielectric Strength: 2200 VAC for one second between all circuits and each circuit to the case with leakage current not exceeding three milliamperes

KD Relay Characteristics & Specifications

Documents

Do You Remember Electromechanical Relays