INSTRUCTIONS3 7

WITH

GEK-45307

TRANSFORMER DIFFERENTIAL RELAYS

PERCENTAGE AND HARMONIC RESTRAINT

TYPES STD15C AND STD16C

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PHILADELPHIA. PA.

POWER SYSTEMS MANAGEMENT DEPARTMENT

ELECTRICGENERAL

GEK-45307

CONTENTS

PAGE

..

....................................................DESCRIPTION .....................................................APPLICATION .....................................................CALCULATION OF SETTINGS .........................................

METHOD ....................................................CURRENT TRANSFORMER CONNECTIONS ...........................DETERMINATION OF CT TURNS AND TYPE RELAY TAP SETTING . .CURRENT TRANSFORMER RATIO ERROR ...........................

PERCENT SLOPE SETTING....................? ..............I DETERMINATION OF CT TURNS AND RELAY TAP SETTING .....11 PERCENT RATIO ERROR ....................................IA REPEAT-CT TURNS AND RELAY TAP SETTING ..................IIA REPEAT PERCENT RATIO ERROR ..........................III PERCENT SLOPE SETTING .................................

RATINGS ......................................................... AND ..............................

AUXILIARY RELAY CONTROL CIRCUIT ...........................CHARACTERISTICS ..................................................

PICKUP AND OPERATING TIME .................................OVERCURRENT UNIT PICKUP ...................................PERCENTAGE CHARACTERISTICS ...................HARMONIC RESTRAINT CHARACTERISTICS ........................

BURDENS .........................................................CONSTRUCTION. ...................................................CURRENT TRANSFORMERS ............................................

THROUGH CURRENT RESTRAINT CIRCUIT .........................DIFFERENTIAL CURRENT CIRCUIT ............................OVERCURRENT UNIT ..........................................

OPERATING UNIT .......................................TARGET AND SEAL-IN UNIT ...................................

CASE ............................................................RECEIVING, HANDLING, AND STORAGE ................................ACCEPTANCE TESTS ................................................

VISUAL INSPECTION .........................................MECHANICAL INSPECTION .....................................ELECTRICAL TESTS ..........................................TEST FACILITIES ...........................................

INSTALLATION PROCEDURE...................~ .....................TESTS .....................................................PICKUP ....................................................HARMONIC CURRENT RESTRAINT ................................THROUGH CURRENT RESTRAINT .................................INSTANTANEOUS OVERCURRENT UNIT ............................DROPOUT OF MAIN UNIT ......................................

LOCATION ........................................................MOUNTING. .......................................................

.....................................................ADJUSTMENTS .....................................................

RATIO MATCHING ADJUSTMENT .................................UNBALANCE CURRENT MEASUREMENT .............................PERCENT SLOPE SETTING .....................................

OPERATION. ......................................................TARGETS ...................................................DISABLING OF TYPE RELAY ...............................

MAINTENANCE .....................................................CONTACT CLEANING ..........................................

PERIODIC TESTS ..................................................PICKUP ....................................................HARMONIC CURRENT RESTRAINT ................................THROUGH CURRENT RESTRAINT .................................

RENEUAL PARTS ....................................................

151515

15

161616171717

1718

i

3INTRODUCTION334444STD566STD777888MODELS 12STD15B 12STD16B88899DIFFERENTIAL910101011111111MAIN1212121212121313131313141415

.15CONNECTIONS15

1616

STD

1717

2

GEK-45307

TRANSFORMER DIFFERENTIAL RELAYS PERCENTAGE AND HARMONIC RESTRAINT

AND

INTRODUCTION

Relays of the STD type are transformer differential relays provided with the features of percentage restraint. A static decision unit controls a small telephone type relay the

Percentage restraint permits accurate discrimination between internal and external faults high while harmonic restraint enables the relay to distinguish, by the between

current caused by an internal fault. and that of transformer Inrush.

DESCRIPTION

Each Type STD relay is a single phase unit. The Type is designed to be used for the of two-winding power transformers and has two through-current restraint and One current circuit.

The Type relay is designed for use with three-winding power and has three throughent restraint circuits and one differential current circuit. It may also be used for four

protection (see Figure 9) when only three circuits require through current restraint, while theth circuit. being the weakest, needs no through-circuit

APPLICATION

The current transformer ratios and relay taps should be selected to obtain the sensitivityout overload of the relay or current or the Of efor transformer in the various windings of the power transformer should be the points in mind:

1. The lower the relay tap and the lower the CT the higher will be the sensitivity. the lowest CT ratio and the lowest relay tap may not be compatible with of the

following restrictions. a choice is available of increasing either the CT Or the it is desirable to increase the CT ratio in preference to the

Since the relay burden is likely to be small compared to the lead burden. increasing the ratio tends to improve the relative CT's as a result Of the secondary fault current and increasing the accuracy of the

The CT should not exceed the continuous thermal rating Of the CT

3. The relay current corresponding to KVA (on a forced cooled should not twice tap value, the thermal rating of the relay.

4. The CT ratios should be high enough that the secondary currents will not the relay under internal fault conditions (refer to RATINGS).

5. The relay current corresponding rated KVA of the power (On Self cooled basis)should not exceed the relay tap value selected (magnetizing inrush might operate the instantaneousavercurrent unit). If the transformer under consideration does not have a the transformer manufacturer should be consulted for the "equivalent self-cooled rating that isthe rating of a self-cooled transformer that would have the same magnetizing inrush

as the transformer being considered.

3

WITH

STDI 6CSTD15C

which provideslarmonicict output .

atdifference in waveform ,

magnetizing •*nt, -inferential

STD15C relaycircuitsaction ,

arential

transformersSTD16Ccircuit

sformerrestraint.

maximumpossibility ' misoperation.

selectedtransformer ,'‘•'king thermal

:vrr*ntiollowing

ratios

ratio selected ,someratio

However ,Where

relay tap.relay tap,CT

maximumreducingperformance of theCT ' s.

secondarysecondary ’current2.winding .

basis ) exceedmaximum

damagemaximum

transformerto

self -cooled rating ,it . x. i

character-istics

Tht - irtructions do not purport to COVT oil d.toih or variohon.Voquip^n^or

f to tho Gantro/ Eloctric Cotnpony.

100% Transformer KVA (Line KY)

Actually this calculation does not mean that all windings will necessarily carry these load currents continuously. This is only convenient of calculating the currents in other windings In proportion to their voltage ratings. This is the requirement for selectingthe relay tap setting so that the relay will not operate for any external fault.

3. Select CT ratios so that the secondary current corresponding to maximum does not exceed secondary thermal rating amperes). In the case where a transformer is connected to ringbus. for example. the CT ratio should be selected so that the CT thermal rating will not be ex-ceeded by the maximum load current in either breaker. Also select CT ratios so that the relaycurrents can be properly matched by of the relay taps. (Highest current not more than 3times lowest current).

For Wye connected CT's

Tap Current N

For Delta connected CT's

Tap Current 100% N

Where N is the number of CT secondary turns.

4. Check the matching of relay currents to relay taps to keep the mismatch error as as possible.

Calculate the percent of mismatch as follows: on two winding transformers, determine the ratio ofthe two relay currents and the tap values The differences these ratios, dividedby the smaller ii the percent of mismatched. The mismatch normally should not exceed 5:.

For transformers, the percent of mismatch error should be checked for all combin-ations of currents or taps.

If taps cannot be selected to this percentage error within allowable limits, it will benecessary to choose a different CT ratio on one more lines to obtain better match betweenrelay currents and relay taps.

Check to see that the sum of the relay currents that be applied to the relay for a fault atthe terminals of'the power transfoner is less 220 amperes for 1 second. If the periodduring which a fault current flows in the relay can be definitely limited to shorter time, hiqher current can be in accordance with the relation:

(Amperes)' seconds

Also check that the sum of the multiples of tap current on an internal or fault do exceed

CURRENT TRANSFORMER RATIO ERROR. CT ratio error be less than 20 percent 8 times relay rated tap Current. This the instantaneous unit being set at its normal setting which is times tap rating. If the instantaneous

pickup is raised above this value, the 20 percent figure must be reduced as described under the heading CHARACTERISTICS.

The calculations listed below are for the worst fault condition, as far as CT is concernedwhich is an internal ground fault between the CT and the transfoner winding with none of the fault Current

through the neutral of the protected

S

GEK-45307

10« I *P JTmaximum

thea way

the CT!P( 5 a

means

, 100% Ip

IpV 3

low

selected. betweenratio,

three-windinq

IceeDaor

will5.RMSthan

aaccommodateda

* 48,400x

external not150.

is based onThe atmust8

unit

performance

transformer.ipplied

i

,Ii

Determine burden on each CT. using the following expressions:

a. connected CT's

2R

b. For delta CT'S

relay total burden (sea Table

N number of turns in bushing CT

bushing CT resistance per turn, (at maximum

CT resistance per lead. (at temperature)

R control cable lead (at expected temperature)

CT current for 8 times tap setting.

8 relay tap rating

(NOTE: For the location of fault assumed. a 11 the fault currant Is by one CT. so that and relay current are the same, regardless of whether the are connected in or

.

Determine secondary CT voltage required 8 times tap setting.

excitation curve of particular tap of current transformer determine excitationcurrent. this secondary

the percent error In each CT by the expression:

error

should not 20 percent on set of If it does. be tochoose a higher tap on that set of and repeat the calculations on selection of relay mismatch error, and percent ratio error.

PERCENT SLOPE SETTING

proper percent slope is determined by the sum Of: .

a. The maximum range of manual taps and the load-ratio-control, or tap means.in percent.

b. The percent of mismatch of the relay taps.

The percentage slope tap should greater than the ratio Of error smaller of the through currents. In general, if the total error current does 20 Percent.

the 25 percent tap is used. If it 20 percent, but not 35 percent. the

the lead is used (as in for example) the percent should be about

SEK-45307

1. the cFor Wye

Z - B Ne + 2f ( EQ. 1 )Ohms1000

connected

Ne + 2f + 2R Ohms ( EQ. 2)Z - 2B 1000

I )Where B - STD

expected temperature)mllHohmse *

maximum expectedmllHohmsf * bushing

maximumresistance* one-way

c. Determine secondary

x STDSsuppliedCT'sCT current

delta . )wye

3. at

E I.Zssecbeing used ,4. From

l £. corresponding to voltage, Esec *

5. Determine

* h x 100t 17sIt w i l l necessaryCT ' s .exceedThis any

CT ' s , taps ,

requiredThechangingautomatic

maximum

maximum : totalnot exceed

40 percent tap Is used .currentselected be

toexceeds

s1 °Pe tap chosenmovabletwice as since

F 'iQure 9r - rp f t rc ^ n t .

If

6

REFER TO FIG.

I DETERMINATION OF C.T. TURNS AN0 RELAY TAP

1. Transformer and Line2. Ip = (line

3 (line turns

5. Max. I secondary (less than 6. 100% I secondary

CT connections Relay Current for 1002 I Sec.

20

1.37

202 47

1.98

12560

2.62

3.60

Select a relay tap for one of the line currents and calculate what the currents in other lines wouldbe they were increased In the ratio. If any current is greater than root three times any other,the 6.7 tap should be chosen for it and ideal relay taps calculated for the other lines.

9. Ideal Relay Taps (Set C = 8.7)10. Try Relay Taps11. Check Mismatch Error

3.31 4.70 a.73 . 2 4.6

Ratio of Taps on Lines B-A = 1.43 of Sec. Lines Currents 1.98- = 1.37

1.

a.7Ratio of Taps on Lines C-6 = 1.89 Ratio of Sec. Line Currents = 1.62

Mismatch = 3.6%1.62

Ratio of Taps on Lines C-A = 2.72 Ratio of SC. Currents 2.63

=

(All are less than therefore. error la not

12. Check the sum of the maximum relay currents is less than amps for one andtherefore. short-time rating of relay is not exceeded.

PERCENT RATIO ERROR

ASSUME (all measured at their expected One-way CONTROL CABLE RESISTANCE =

CT;

c Bushing resistance per lead

18.6

.

1. BURDENS ON CT'sUSING 1 OR 2 from page 5.a. A. Z 2 l (2.0

000

0.312 0.205 l 1.085 l

+ 0.0% l 0.136 + 0.60

c. Line C. Z = 2 (0.046) + 100 + = 0.0% l 0.180 0.568 = 0.833

GEK-45307

EXAMPLE 17SETTINGSSTD

A CB19.73750/ VIT

3. 100% Ip «3000/ V. 4. Assume CT

1?7KV) 49.5Max.KV ) 15.7 39.6

(N ) 0.98 » »

5a) 0.79 1.582.08v •r ^

Delta DeltaWye7.8.

1f samenew

8.7

4.6 1.44Ratio3771.44 1.43 , 0.7%Mismatch 43

4.61.89 - 1.82

8.7 Linen2.72 - 2.63 3.4%Mismatch

excessive)mismatch5%;

220 second,that

IItemperatures)maximum

(R ) .284 ohms4 mllHohmsresistance per turn (e) »;e) - 2.5 "

e) - 2.3 "f ) - 75 "f ) - 52.5 "

( f ) *

Bushing AH DB

< 4

A CTB "

4!C “

EQ. EQ.• (0.156) x 75)(20 x *, )Line + 2 (.284)1

0.568 -( 2.1 x 52.51( 20 x 2.51 ©.seak.UlT* 2 * ©-'1S5 IDDO

0.568 *( 60 x 2.3) + (2 x 18.6) 0.56800

7

2. 1.085 0.8 0.833

3. a 36.8 69.6

ES CT required 27.8 29.b 58.0 required, excitation curve 1.00 50

Ratio Error 3.4% 136%Exciting current on line is high; should try higher tap on CT to improve CT

IA REPEAT CT TURNS AND RELAY TAP SETTING

1. Try CT turns (necessary to change C

also for proper matching)3. I s e c o n d a r y

Relay Current.Ideal Relay (SET C 8.7)

6. Use Taps7. Mismatch error is less than

Total Burden for 60 Cycle Relays

15.7 39.6 125

0.791.374.404.6

40 800.99 1.560.99 2.70

TABLE I

IIA REPEAT PERCENT RATIO ERROR

1. Burden on CT'sLine A. Z 0.192 0.205 0.965Line 0.156 + 0.568 0.912Line Cm Z 0.096 + 0.226 0.890

2. Impedance. 3. 8 Times Tap, Amperes 36.8 25.6

CT voltage required 35.6 23.45. required, from excitation curve 1.1 0.256. of Ratio Error 3.1% 1 .

Percent Error is less than 20%. so CT taps and Relay taps are satisfactory.

69.661.9

0.170.3%

III PERCENT SLOPE SETTING

1. Assume load ratio. control maximum range2. Relay Tap mismatch, IA above (Lines

10.0 :4 . 6 :

Use 25% tdp.

R A T I N G S

14.6%

- - -

Continuous rating The through current transformer differential transformer Will standtwice value for any of taps or they will stand twice tdp value if all but one of

carry zero current the full restraint current. equal to twice tap the current transformer.

GE<-45337

A B CohmsImpedance,

T imecanoeres 25 . *?

* a n ( 12 )4. voltagefromIE.5. 0.5

6 . 0.8%* B too performance.

1002 Ip2.

20100?

4.Taps5. 3.19 8.7a

3.2 8.75S

MIN. P.U. AMPS iBURDEN OHMS ( B )8 X TAP AMPSSTD TAPS AMPS!

0.870.1800.1560.1400.1200.1120.0960.0880.048

23.22.9 0.9625.6>. 2 1.0528.03.5 1.1430.43.8 1.2633.64.2 1.3836.84.6 1.5040.05.0 2.6169.68.7

0.568 *s

0.188 +B,Z * S

0.568 =S

Ohms . 965 . 912 .890

( I Z )E $ec «4.IE

0%l

A-B)from

MODELS 12STD15C AND 12STD16C

and Currentcomfcinati ontap t f ie ,res -

value, flows throughtraint windinqsdif ferential

and

8

amperes for second measured in the primary Of any nigher may be applied for shorter lengths of time in accordance the

1%

where:

I current amperes

t time in seconds

Short Time (electrical) For the and the Of the multiples Of tap fedto the relay from the several sets of current transformers should not exceed 150. These multiples shouldbe calculated on the basis of fault current. This limitation is a result of the voltage

of the rectifiers in the through current restraint Note that in Fig. 9 external faultcurrent can flow through circuit breakers and 52-2 without being limited by the Impedance.

TABLE II

2.0 0.6 , 0.2 Tap Tap Tap

D-C Resistance 0.13 0.6 Ohm 7 Carry Continuously 0.5 Amps 1.5 Amps 0.25 carry for 4 0.5 ---- Carry 10 Amps for 30 4 0.2

AUXILIARY RELAY CONTROL CIRCUIT

The and relays are available for use with 48. 125, and 250 d-c voltage. A with small links located on the front of the relay enables the selection of one of these voltages.

The relay is provided with two open contacts connected to a output circuit. The currentclosing rating of the contact is 30 amps for voltages not exceeding 250 volts. If more than one break& is to be tripped or if the tripping current exceeds 30 amperes. an auxiliary relay must be usedwith the relay. the breaker trips. it is necessary that the tripping circuit of these be de-energized by an auxiliary switch on the circuit breaker by other reset relay is and normally used.

CHARACTERISTICS

PICKUP AN0 OPERATING TIME

The operating characteristic Is shown in Fig. 1. The curve for various percentage thepercent slope versus the through current flowing in the The percentage slope is a figuregiven to a particular slope tap setting and indicates an approximate pickup atzero restraint is 30 percent of tap value (see Table III). The dropout time theoperating current is reduced from any value above pickup to zero is less than 25

of the operating time of the main unit and of the instantaneous unit are shown in Fig. plotted against differential current. The main operating time includes auxiliary unit operating time.

OVERCURRENT UNIT PICKUP

The unit is adjusted to pickup when the differential ‘8 times the ampere produced by rated tap current flowing in that For example:

only one supplies current. and the tap plug for the CT is in the ampere tap, 40amperes are required for pickup. This pickup value is on the A-C Of current

only, since the differential current transformer in the relay a halfcycle of any d-c present.

GEK-45307

* transformer z*withShort Time Rating ( theflW ?

che type STD relay ,following equation: •

• 48.400

220 1i -currents

s

=1

currentSTD15C STD16Cboth sum

RMS symmetricalcircuit.rating

transformer52-1

TARGET AND SEAL- IN UNIT

AmpAmp AmpOhmsOhms

AmpsSecs.

Secs.30 Amps Secs.Secs. Secs.

controlSTD15C STD16C>» iate

STD commoncircuit

relaysautomatic provisions. A manualSTD After

orrecommended

slopes showstransformer.

slope characteristic .when

milliseconds.approximately

2,Curvesunit

current transformer ampere- turns aretap.overcurrent

turns

5CTWhentrans-based component

produces onlyformer output(offset)component

9

It should be recognized that pickup current flows not only through current transformerbut also through one of the primary windings of the through current restraint.

However, compared to the operating energy, this quantity of restraint is so small it may assumedto be zero.

CURRENT RESTRAINT CIRCUIT

A full wave rectifier receives the output of the secondary of each through current restrainttransformer. In the relay. the d-c output of all three units are connected in The totaloutput is directed to the percent slope rheostat located on the front of the relay. By means of'adjusting the rheostat, the percent slope may be varied 15 to 40 percent. The is put throughan isolatinq transformer, rectified and to the solid state amplifier which thetelephone tyoe relay.

DIFFERENTIAL CURRENT CIRCUIT

The differential current secondary supplies the instantaneous unit theoperating signal to the solid state amplifier through a series tuned circuit; and the harmonic restraintisolating transformer through a parallel resonant filter. The operating and restraint currents are eachrectified by a full wave bridge prior to being supplied to the sensitive amplifier.

The series resonant circuit is made up of a microfarad capacitor (Cl) and a reactor which are tuned to pass currents of the fundamental system frequency and to offer high impedance toCurrents of other frequencies. Resistor is connected in the a-c side of operate and can be to give the desired amount of operate current. The output of the is applied

the operating of the sense amplifier.

The parallel resonant trap is made of a 15 microfarad l Pyranol capacitor and a reactor which are tuned to block fundamental frequency currents while allowing currents of to pass with relatively little impedance. Resistor R2 is connected in parallel on the a-c side of theharmonic restraint rectifier, and can be adjusted to give the desired amont of harmonic restraint. Theoutput of the rectifier is paralleled with the through current restraint currents and applied to restraint of the sense amplifier.

It will evident that if the differential current applied to the relay is sinusoidal and of system will flow mostly in the operating circuit and hence cause the relay to yield an output.

if. however. the differential circuit contains than a certain percentage of the relay willbe restrained from by the harmonic currents flowing in the restraint

A resistor connected across the secondary of the differential limitsany momentary high voltage peaks which may thus protecting the rectifiers and capacitors damagewithout materially affecting the characteristics of the relay.

OVERCURRENT UNIT

The instantaneous unit is a hinged armature relay with a self contained target indicator. On heavy internal fault currents. this unit will pick up and the trip circuit. The unit target will be exposed, to indicate that tripping was through the instantaneous unit.

Because of saturation of the CT's and relay transformers at high fault currents, it is impossible thatless operating currents will be provided from the differential-current than the percentageslope tap imply, and harmonic restraint will be provided than the actual harmonic content of the

would supply. As a result, conditions of a high internal fault current, the unitmay be falsely restrained. Tripping is assured, however, by the overcurrent unit operation. Pickup set above the level of differential current produced by maximum magnetizing inrush current. Figure 2

the relative levels of pickup and speed of operation of the unit and the overcurrent unit.

l Trade-Mark of the Gener a l Electric Company

GEK-45307

differentialtransformer producing some

that be

THROUGH

brldaeSTD16C parallel.

(«3 )from

sensitiveoutput

controlsdirected

directly;transformer

5 * Pyranol

parallel on

(LI)

R1 rectifiertneadjusted rectifier

to circuit

( C2 ) { 12 ) .harmonic frequencies

thecircuit

befreouency, it

harmonics,circuit.more

operating

current transformerThyritefromoccur,

ex-instan-completetremelytaneous

transformerwould

' fault currentmore

under mamis

shows main

Registered

\ 2

OPERATING UNIT

The primary functioning of the relay is a state amplifier whose controls asimple telephone relay. The sense ampllfler is shown In Fig. 10 and as a large rectangle. The amplifierconsists of many electronic components mounted on a printed circuit card in the top half of the relay.

This printed card is installed in an eight-prong printed card design base. This Is adjusted prior the factory and should require no further attention. A schematic of thiscard is shown in Fiq. The telephone-type relay is mounted vertically in the mid-section of the relay.It too has been carefully adjusted at the factory and should require no further attention. If this smallrelay has been disturbed, refer to the section under adjustment.

TARGET AND SEAL-IN

a target and seal-in unit mounted on the top left of the relay. This has Its coil inseries and its contacts in parallel with the main contacts of the telephone-type relay. the type relay contacts close, the seal-in unit operates; raising its target into vision and sealing aroundthe telephone type contacts. The target of this unit will remain exposed until released by pushing abutton beneath the lower left corner of the cover of the relay case.

The case suitable for surface or semi-flush panel mounting, and an assortment of hardware is pro-vided for method. The cover attaches to the case, and carries the target reset mechanism for the

indicator and instantaneous unit. Each cover screw has provision for a sealing

The case has studs or screw connections at the bottom for the external connections. The connections between the relay unit and the case studs are made through spring backed contact finger mountedin stationary molded inner and outer blocks between which rests a removable connecting plug which completes

circuit. The outer block, attached to the case, holds the studs for the external connection, and the block has terminals for the internal connections.

The relay mechanism is mounted in a steel framework called the cradle and is a unit with allleads terminating at the inner block. This cradle held in the case with a latch at the top and

a guide pin at the back of the case. The case and cradle are so constructed that the relaycannot be inserted in the case upside down. The connecting plug. besides the connectionbetween the blocks of the cradle and case, also locks the latch In place. The cover. which fastened tothe case by thumbscrews. holds the connecting plug in place.

To draw out the relay unit, the cover is removed and the plug is drawn out. Shorting are providedin the case to short the current circuits (see Fig. 6). The latches are then released and therelay can be easily drawn out.

A separate testing plug can be inserted in place of the connecting plug to rest the relay in Onthe panel either from its own source of current, or from other sources. Or, the relay unit can be drawnout and replaced by another which has been tested in the laboratory.

RECEIVING, HANDLING OR STORAGE

These relays, when included as a part of a control panel will shipped In cartons designed protect them against damage; upon receipt of a relay, examine It for any damage intransit. If injury or damage resulting from rough handling is evident. file a damage claim at once withthe and promptly notify the nearest General Electric Apparatus

Reasonable care should be exercised in unpacking the relay in order that none of the parts are or the adjustments disturbed.

If the relays are not to be installed they should be stored in original cartons ina place that is free from moisture, dust and metallic chips. Foreign matter collected on the outside of

case may find its way inside when the cover is removed and cause trouble in the operation of the relay.

GEK-J 5307

iIN

sol Idunit STD output11

componentcircuitto leaving

18.

UNIT

unitThere istelephone-When

CASE

1 seither

wire.trip

electrical

ner

completefirmlyis

bottom and .byelectricalmaking

1s

barstransformer

unit

place

tobenotsustainedImmediately

Sales Office.transportation company

injured

theirimmediately,

the

13

ACCEPTANCE TESTS

the relay an inspection and acceptance test be to insure thatthe relay has not been in and that the relay calibrations are unchanged.

VISUAL INSPECTION

Check the nameplate stamping insure that the model number. rating and calibration range of relay received agree with the

moldedRemove the relay from its case and chock by visual Inspection that there are no broken crackedparts or other signs of physical damage and that all screws are tight.

INSPECTION

thatCheck the of the telephone type relay and instantaneous overcurrent unit manually to seethey operate smoothly without noticeable friction or binds. Check the contact gap and of these

units which should agree with values given under the section on

It is that the electrical tests be upon receipt of relay.

1. Minimum pickup of main operating unit.2. Minimum pickup of the Instantaneous overcurrent unit.3. A single check on the restraint characteristic.4. A single check point on the slope characteristic curve for slope to be used.

TEST FACILITIES

In order to facilitate tests, the following test is

1. Two load boxes for regulating the test currents.2. Three (2 A.C. and O.C.) for measuring the test currents.3. A test rectifier for checking the relays response to the second harmonic.4. One indicating lamp.5. single pole double switch selector.6. A double pole single throw line

Chock the unit connections shwn In Fig. 12. this test. the selectorswitches and are open and current passes through the differential circuit only. For example, witha relay with a 25 percent slope and at the 2.9 ampere ratio matching taps, the main unit should pick

at of tap rating plus or minus 10 percent, or the pickup should be between 0.78 and 0.96amperes. To check that the main unit has picked up a source of DC pwer at rated voltage should connected shown Fig. 12, and the Indicating lamp will provide a signal showing that the main unithas operated.

For an additional pickup test, the pickup should be 1.5 amperes with current flowing terminals 5and 6 and the tap plugs in the 5 ampere tap, and the 25 percent slope tap position. If the pickup isbetween 1.35 and 1.65 amperes, no adjustment should be made. The pickup of the relay-has wider variations than most protective relays, but due to the relay design and application, the relay accuracyis entirely adeuqate under all conditions even during transformer magnetizing inrush or severe fault a

the selector switch, in the A position,the section on INSTALLATION PROCEDURE.

check the current restraint described

The instantaneous unit should be chocked by passing a high current through the 5-6The pickup should be about 8 times tap rating.

Check through current restraint as described under section on INSTALLATION PROCEDURE.

14

6EK-45307

Immediately upon recelptofdamaged shipment

should made

to therequisition.

or

MECHANICAL

ooeratlonwipe

SERVICING.

followlngrecormiended made Immediately the

point harmonicapproximate expected

equipment recommended:

1aimeters

.Two throwswitch.

pickup of the main During(S2 S4 )

setup 30 percent

beas in

in

permissable

conditions.With S2 harmonic as

under

overcurrentterminals.

This curve represents the relay characteristic. of a voltage across studs 8 and 9which is 75: or less of the value given on the curve does not necessarily indicate that operate at higher through current This is especially true where very high through maycause CT saturation.

Small rectifier-type AC voltmeters are suitable for the measurement of unbalance. voltmetershould not be left permanently connected since the shunt current it draws reduces the

PERCENT SLOPE SETTING

Scribe marks for 15. 25 and 40 percent slope settings are provided In both the and relays. It practice to use the 25 percent setting unless special connections make It advisableto use one of the others. See the corresponding heading under CALCULATIONS for further details.

T A R G E T S

Targets are provided for both the seal-in unit the unit. In event of an internal fault. one or both of these units will operate depending upon the fault magnitude.This will produce a target of the unit which operates. After a fault Is cleared.the target should be reset by the reset slide located at the lower left hand corner the

DISABLING OF TYPE STD RELAY

When by-passing a breaker for maintenance, will be necessary to disable the relay to prevent tripping. If the disabling of the relay is done by a remote switch rather than by the relayconnection plug, the following precautions should be taken:

1. The relay may be disabled by short-circuitino studs 8 and 9 of the relay or by opening the circuit at stud 1.

2. If the CT secondaries are short-circuited as part of the disabling procedure, the trip circuitshould be opened at stud 1 and studs 8 and 9 should be short circuited first. It is not to relyon short circuitingthe CT secondaries alone, because any difference in time of shorting them false tripping.

CONTACT CLEANING

For contacts. a flexible burnishing tool should be used. This consists of a flexiblestrip of metal with an etched roughened surface , resembling in effect a superfine file. The polishingaction is so delicate that no scratches are left. yet corroded material will be removed rapidly and thoroughly.The flexibility of the tool insures the cleaning of the actual points of contact.

Contacts should not be cleaned with knives. files or abrasive paper or cloth. Knives or files leave scratches which Increase arcing and deterioration of the contacts. Abrasive paper or cloth leave minute particles of insulating abrasive material in the contacts and thus prevent closing.

The burnishing tool described in the standard relay tool kit obtainable the factory.

PERIODIC TESTS

An operation test and Inspection of the relay and its connections should be made at everysix months. Tests may be performed as described under INSTALLATION TESTS if desired. they MY be

on the service taps as described in this section.

Inserting or withdrawing a test plug with U-shaped through jumpers to complete the trip circuitthrough the test plug, similar through jumpers should also be used on studs 8 and 9 to maintain theconnections the relay to the case. If this is not done, there is a risk of false tripping upon in-serting or withdrawing the plug.

SCK-45307

MeasurementSTDthe relay will

faultsvalues.

Therelay sensitivity.

STD15 STF16is common

OPERATION

instantaneous overcurrent theand

indication particularrelay.of

falseitremoving

trip

sufficientmay cause

MAINTENANCE

cleaning

maymay

is included from

least onceor ,

made

When

from

18

C K U P

The pickup is as described under the heading INSTALLATION of current be different depending upon the UDG Pickup value be determined as

0 .30 1 T a p

IO percent variation Still course, when pickup on a particular service the the acceptable as found values being

II 0.30 YDG Tap to 1.10 0.30 UDG I

Example UDG 1 Tap 0.90 x 0.30 3.5 to 1.10 0.30 3.5 0.94 to 1.16 amperes

CURRENT RESTRAINT

The for harmonic restraint Is as described the heading TESTS the test current values must be modified follows:

12 (DC) 0.80 x UDG 1 Tap UDG I Tap to 1.10 x 1

In event a suitable DC meter available. I2 (AC) 2.25 (DC). (Theoretically be 2.22 if the rectifier back resistance

UDG 1 lap 0.80 x 3.5 2.8 amperes

0.90 x 3.5 to 1.10 3.5 3.15 to 3.85 amperes

If DC meter is not available, (AC) 2.25 x 2.8

RESTRAINT

order to check the the current values indicated in Table IV must to take into account any difference the circuit in

of is connected to the stud to the tap I4 the lead from 13 to the test Plug is to the stud

setting. For any combination of taps, percent slope is given by the

Slope

where

smaller tap setting

higher tap setting

differential current

smaller of the two through currents

GEK-4530?

TESTS except, course.method for checking1 service tap.willckup

Hows:may

x WDGI I *tap,checking expectedOf i.

plies.Tap•0.90 x 1 x XX

*3.5AII * xXX

II"1RM0NIC

INSTALLATIONundercheckingprocedure<cept as

M

WOG TapIj * 0.90 xthis1s not $ T •>

were Infinite).the *anverslon factor would

- 3 . 5AimpleI2 (DC ) * s

h = X

n -6.30 amperes12

"HROUGH CURRENTservice tap slope setting, test

'in tap settings.

corresponding

In shown5e modifiedf1g. - .must be set up such thatIhe conmon lead ^

Furthermore, testconnected

winding Wftn the higherfoTlowing equation:

setting.ammetercourse,

the'T1

( I1 x 100-1+ 1X3

Tl "T2 *

h -h "

19

. . FIG. 1 LOW CURRENT OF THE RELAY

GEK-45307

80r NOTE: FOR TWO WINDING TRANSFORMER RELAYS"THROUGH CURRENT" IS TAKEN AS THE SMALLEROF THE TWO CURRENTS. FOR THREE WINDINGTRANSFORMERS, IT IS TAKEN AS THE SUM OFTHE INCOMING OR OUTGOING CURRENTS, WHICH-EVER IS SMALLER. (EACH CURRENT TO BEEXPRESSED AS A MULTIPLE OF TAP.)701

50

,40*4

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STDSLOPE CHARACTERISTICS( 0378A588- 3 )

22

INSTALLATION PROCEDURE

TESTS

Before placing the relays I" , check the relay calibration to be used in its final locationto insure that It Is correct. The following test procedure is outlined for this purpose.

CAUTION: RELAY CALIBRATION IS ACCOMPLISHED BY ADJUSTING RESISTORS RIN ME

.IN ANY ONE THESE RESISTORS WILL AFFECT THE OTHER TWO SETTINGS. IS CHANGED.

PICKUP, RESTRAINT, AND CURRENT RESTRAINT ADJUSTMENT PROCEDURES SHOULD BE REPEATEDUNTIL FURTHER DEVIATION FROM PROPER CALIBRATION IS NOTED. BEST RESULTS CAN BE OBTAINED IF THE CURRENT ADJUSTMENT IS MADE ONLY AFTER THE OTHER TWO SETTINGS ARE CORRECT.

The-test circuit for pickup is shown in Fig. 14 with open. Pickup should be 1.5 amperes withcurrent flowing in terminals 5 and 6. and the tap plugs in the 5 ampere position. and 25 percent slopetap setting.. The pickup operation should be repeated several times until two successive readings agree

ampere and the total pickup current being interrupted between successive checks. pickupis found to be from 1.35 1.65. the setting should not be disturbed.

With d-c control voltage to the proper terminals of the relay. the pickup of the telephonetype relay can be used as an indication of operation of the amplifier. This voltage may be applied as

in Fig. 14 and the indicating lamp will verify that the has produced an output signal.

Before adjusted for pickup. put a D.C. voltmeter (1 volt scale) on pin 2 and pin of the sense card. The pins are counted from right to left when viewed from the card socket

connections. Apply pickup current and adjust for a voltage input to the sense amplifier cardof 5.430 to 0.470 volts. If the pickup is not in with this setting then adjust on the senseamplifier card to obtain the proper pickup value.

CURRENT RESTRAINT. .The restraint adjusted by means of a Test Rectifier used in conjunction with

and load boxes. The test circuit is as shown in Fig. 14 with to position A. Testsshould made on the 5.0 ampere and 25% slope taps.

analysis of a single phase half wave rectified current shows the presence of percentages of and second harmonic components as well as percentages of all higher even

harmonics. This closely appmximates a typical inrush current as seen as the relay in as much as its principal components are d-c. fundamental, and second harmonic. Although the percentsecond is fixed, the overall percentage may be varied by providing a path for a of by-passed current of frequency. The by-passed current is added in phase with fundamentalcomponent of the half wave rectified current and thus provides a means of varying the ratio of secondharmonic current to fundamental current.

The following expression shows the relationship between the percent second harmonic. the d-c component.and the by-pass current.

Second 0.212 100

+ 0.5

Figure 15 is derived fmm the above expression. It shows the percent second correspondingto various values of by-pass current (II) for a constant d-c set at 4.0 amperes.

The relay calibrated with a composite current of two time tap value. properly set the will restraint with greater than twenty percent second harmonic but will operate with second

harmonic equal to twenty percent or lower. With the d-c (I ) at 4.0 amperes, the should just begin to close its contacts gradually increa by-pass current (I at a value

4.5-5.5 amperes. This corresponds to percent second harmonic (see a two percent tolerance at the set point to compensate for normal fluctuations in pickup. It should be notedthat the current nangitude in the rectifier branch (I ) is slightly influenced by the Of by-pass current and should be checked to insure it maintained at its proper value.

15

SEK-45307

service

CHANGES MADETHE SETTINGOF EVEHARMC'NIC THROUGHTHE

THROUGHNORESTRAINT

PICKUP

S2

Ifwithin O.Ol

applied

amplifiershown(- )

amplified8 ( )

limitswiring

pi

HARMONIC

harmonic 1s suitaoleS2 closedammeters

be

The fixednegligibled-c, fundamental,

terminalstransformer

harmonic controlled amoantfondamental

IHarmonic *X d-c x0.451 I1 d-c

harmonic

Whenis RMSrelay

*elayauxiliarysetammeter ^1ngwith

Fig. 15) providingapplication

i f 19-21

?;(i,)i

If harmonic restraint is found to be of adjustment. it be corrected by adjusting Rheostat

THROUGH CURRENT

The through current restraint. which gives the relay the percentage differential or percent slopecharacteristics are in Fig. 1. It may be checked and adjusted using the circuit illustrated in Fig.

with closed to II reads the differential current and I3 reads the smaller ofthe two through currents. In testing relays, the setting should be checked with the switch firstin one position and then the other, thus checking all the restraint coils. Uith the current

ampere position and the percent slope tap plug in the percent position, the relay should Just up for values of the I and 13 currents indicated in Table IV. Repeat with the percent slope tap plugin the 25 percent and 5 percent position. If any one of these Set points is found to be the other than asprescribed. the adjustment may be made by adjusting It should be noted that the current magnitude in

the through current branch (13) is slightly influenced by the application of differential current (II) andshould be checked to insure that it maintained as its proper value.

Any in to give the desired slope will have small effect minimum pickup and harmonicrestraint. However! after the slope setting has once any adjustment of minimum pickup will changethe slope The slope set points must then be rechecked to insure that they are inaccordance with Table III.

NOTE: These currents should be permitted to flow for only a few seconds at a time cooling between tests; otherwise. the coils will be overheated.

NOTE: The percent slope tolerance is 10 percent of nominal. all in the plus direction. This is to the slope characteristic never falls below tap value.

TABLE IV

PERCENT POSITION AMPERES TRUE SLOPESLOPE TAP' ON RHEOSTAT II

MiddleLeft

INSTANTANEOUS OVERCURRENT UNIT

This unit is at the upper right-hand of the relay. Its setting may by passinga high current of rated through and 6. The unit should pick up at times the taprating as described under CHARACTERISTICS. If the setting is incorrect. it may be adjusted by looseningthe lock-nut at the top of the unit and turning the cap screw until the proper pickup is obtained. In

this adjustment. the current should not be allowed to flow for more than approximately one second i i m e .

DROPOUT OF UNIT

After the other tests are complete, check the dropout of the main as described under ACCEPTANCETEST section.

LOCATION

The location should clean and dry. free dust and excessive and tofacilitate inspection and testing.

MOUNTING

The relay should be mounted on a vertical surface. The outline and panel drilling are in Figure 5.

SEK-45307

out may

RESTRAINT

shownposition B. Anmeter14 S2

S4ST016Ctap plugs in

pick40' 5.0

1R3 -

is

change R 3 uponbeen . set ,

characteristics.

periodswith

Insure that

Oi / 13 * 100)1340.0-44.025.0-27.515.0-16.5

12.0-13.27.5- 8.34.5- 5.0

3040 Right30253015

be checkedlocated side8terminals 5frequency

makinqat a

MAIN

unit

well lightedvibration.be from

dimensionshown

16

CONNECTIONS

Internal connection diagrams are shown in Figs. 10 and 11.Figs. 7. 8 and g for differential applications.

Typical wiring diagrams are given in

Of course, any through current winding may used for any provided the taps are properly chosen.

the relay is mounted on an insulating panel, one of the supporting studs should be cntly grounded by a conductor not less than No. 12 AUG gage copper wire its quivalent.

Every circuit in the case has an auxiliary brush.the connecting plug should engage first.

This is the shorter brush in the case whichOn every current circuit or other circuit witn shorting bars,

make sure the auxiliary brushes are bent high enough to engage the connecting plug or test plug before themain brushes; otherwise. the CT secondary circuit may be opened where one brush touches the shorting before the circuit is the plug to the other main brush.

ADJUSTMENTS

, RATIO

TAP PLUG POSITIONING

To obtain unbalance current in the'differential circuit. means in the relayto compensate for unavoidable differences in current transformer ratios. Taps on the relay primary are rated 8.7, 5.0. 4.6. 3.8. 3.5, 3.2 and 2.9 amperes for each line current The tap plugs should be to the locations which most nearly match the expected CT currents for thesame KVA assumed in each of power transformer windings.method outlined under CALCULATIONS.

The selection of should be guided by theThe connections plug must be removed the relay before changing

tap positions in order to prevent open-circuiting a CT secondary. A check should be made after changing to insure that only one plug is left in any horizontal row of tap holes. Inaccurate calibration overheating may result if more than one plug is connected to any one uinding.

UNBALANCE CURRENT

Unbalance current is useful in checking the best tap setting when matching current former ratios in the field. It is also useful in detecting errors or faults in the transformerwinding, or small faults within the power transformer itself where the fault current is too low to operatethe relay.

The type STD relays have a special arrangement for the unbalance current flowing in thedifferential circuit without disturbing the relay connection. Provision is made for temporarily connectinga 5 volt high-resistance A.C. voltmeter (1000 or more per volt) across the secondary of the current

and 11).This may be done by connecting the meter across 8 and g (see Figs. 10

a perfect match of relay currents is obtained by the ratio matching taps, the voltmeterwill read zero. indicating no unbalance. If the voltmeter reads 1.5 volts or less. the unbalance currententering or leaving a given tap approximately 0.03 times the voltmeter reading times the tap

For higher voltmeter readings, the approximate unbalance current may be calculated thevoltage reading tap rating into the following equation:

(Unbalance) 0.2) Tap'

The unbalance percentage 100 times the unbalance current divided by the measured tap For a three winding bank. this checked with load on at least two pairs of In order toinsure that the connections are correct.

The curves in Fig. 16 show the approximate voltage across terminals 8 and g to operate the ielay for various percent slope tap settings and through currents expressed as percentage of tap. Toinsure a margin of safety against false operation, the unbalance voltage should not exceed 75 percent ofthat required to operate the relay for any given through current and percent slope tap setting. This

of unbalance may result the relatively high error currents of low ratio bushing CT's at low of tap current.

GEK-45307

transformer be power transformer winding

When steel perman-ordrawout

barcompleted from

MATCHING ADJUSTMENTa minimum are provided STD

transformertransformer.windings

movedthe taps

from

’ps.d

MEASUREMENT

trans-measurmentcurrent

measuring

differen-ohmst1al transformer. terminals

When

equals rating.by substituting

and

I « ( 0.16V - xequalsmust be

current.windings

required

•xtent from1 tiples

17

This curve represents the relay characteristic. of voltage across studs 8 and gwhich or' less of the value given on the curve does not necessarily indicate that willoperate at higher through current values. This is especially true where very high through faults Mycause CT saturation.

Small rectifier-type AC voltmeters are suitable for the measurement Of unbalance. The should not be left permanently connected since the shunt current it draws reduces the relay

PERCENT SLOPE SETTING

Scribe marks for 15. 25 and 40 percent slope settings are provided in both the ST015 and STF16It is practice to use the 25 percent setting unless special connections make it advisable

to use one of the others. See the corresponding heading under CALCULATIONS for further details.

OPERATION

TARGETS

Targets are provided for the seal-in unit the instantaneous unit. In event of an internal fault. one or both of these units will operate depending Won the fault magnitude.This will produce a target indication of the unit which operates. After a fault is cleared.the target should be reset by the reset slide located at the lower left hand corner of the relay.

DISABLING OF TYPE STD RELAY

by-passing a breaker for maintenance. it will be necessary to the relay to prevent falsetripping. If the the relay is done by a remote switch rather than by removing the relay

plug, the following precautions should be taken:

1. The relay may be disabled by short-circuiting studs 8 and g of the relay or by Opening the circuit at stud

2. If the CT secondaries are short-circuited as part of the disablfng procedure, the circuitshould be opened at stud 1 and studs 8 and g should be short circuited first. It is not to relyon short circuitingthe CT secondaries alone. because any difference in time of shorting them may causefalse tripping.

MAINTENANCE

CONTACT CLEANING

For cleaning contacts, a flexible burnishing tool should be used. This consists of a flexiblestrip of metal with an etched roughened surface, resembling in effect a superfine file. The action is so delicate that no scratches are left, yet corroded material will be removed rapidly and thoroughly.The flexibility of the tool insures the cleaning of the actual points of contact.

Contacts should not be cleaned with knives, files or abrasive paper or cloth. Knives or files mayleave scratches which increase arcing and deterioration of the contacts. Abrasive paper or cloth mayleave minute particles of insulating abrasive material in the contacts and thus prevent closing.

The burnishing tool described is'included in the standard relay tool kit obtainable the

PERIODIC TESTS

An operation test and inspection of the relay and its connections should be made at once everysix months. Tests may be performed as described under INSTALLATION TESTS or. if desired, they may bemade on the service taps as described in this section.

When or withdrawing a test plug with U-shaped through jumpers to the trip circuitthrough the test plug, similar through jumpers should also be used on studs 8 and g to maintain theconnections the relay to the case. If this is not done, there is a risk of false tripping upon serting or withdrawing the plug.

&K-45307

STD Measurement athe relayis 75S

voltmetersensitivity.

relays. common

overcurrent theandboth

particular

disableWhendisabling of

connectiontrip

1.trip

sufficient

polishing

factory.from

least

comp!eteInserting

1n-frcm

18

method checking pickup is as described under the heading INSTALLATION of current will be different depending upon the 1 Pickup value may be determined as

11 0.30 1 T a p

when a particular service tap, the percent the as found values being

0.90 0.30 1 Tap to 1.10 0.30 1 T a p

Example UDG 1 Tap 0 .30 3.5 to 1.10 0.30

3.50.94 to 1.16 amperes

CURRENT RESTRAINT

restraint is as described the the test current values must be modified as follows:

12 (DC) 0.80 WOG 1 Tap to 1.10 UDG L

In the event a suitable DC meter not available. I2 (AC) 2.25 (Theoretically this be 2.22 if the rectifier back

0.80 3.5 2.8 amperesIL 0.90 3.5 to 1.10 3 . 5

3.15 to 3.85 amperes

available, (AC) 2.25 2.8 6.30

CURRENT RESTRAINT

order to check the service tap setting. the test current indicated in Table IV modified to take into account any difference the test

the lead from 13 to Plug is to stud connected to the stud to the with

setting . For combination of taps, percent slope is given by the

l

where

smaller tap setting

higher tap setting

I1 differential current

smaller of the two through

19

GEK-45307

CKUPTESTS except, course ,forThe

WDG service tap.ckupHows:

x WDGexpected variation still+ 10'•-heckina pickup onOf course,

acceptablep l i e s ,

xWOGx UDGII - xX

11* Sl 5A

90 x XXX

II “WMONIC

heading INSTALLATION TESTSunderThe procedure for checking harmonic<c e p t

TapxTapI j - 0 . 9 0 x U D G 1 x - xI ?

T(0Cl.

resistance were Infinite ) .i s.inversion factor would

jmple WDG 1 Tap = 3.5A^ I 2 ( DC ) « ‘

XX3 X

I I 3

amperes12If DC meter1snot *X

UROUGHmustvalues

in tap settings. Furthermore,ammeter

slopeI n circuit shown inje setting.connected thewinding the higher tapfollowing equation:

the testcorrespondingr1gJ 4.mustf. be set up such that

The common lead , of course, istheany

11 x 100-11l Slope = *1r2

Tl “T2

'

currentsi 3 -

I I I I I I I I

FIG. 1 CURRENT SLOPE CHARACTERISTICS OF THE RELAY

22

GEK-45307

80 r NOTE: FOR TWO WINDING TRANSFORMER RELAYS"THROUGH CURRENT" IS TAKEN AS THE SMALLEROF THE TWO CURRENTS. FOR THREE WINDINGTRANSFORMERS, IT IS TAKEN AS THE SUM OFTHE INCOMING OR OUTGOING CURRENTS, WHICH-EVER IS SMALLER. (EACH CURRENT TO BEEXPRESSED AS A MULTIPLE OF TAP.)70

440*

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2 OPERATING SPEED CHARACTERISTICS OF THE RELAY

F I G . 3 ( K - 6 2 0 9 1 9 5 - 0 )

2 3

6EK-45307

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AVERAGE OPR.TIME MAIN UNIT

INST. UNIT.

3

V% X*I 2 \iS) VUJ

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0J-5 RELAY DIFFERENTIAL CURRENT IN MULTIPLtS W IAK

FIG. (0227A25Q3-0) STO

< iiTYPICAL OFFSET FAULT CURRENT RAVE

TYPICAL TRANSFORMER

MAGNEWNG INRUSH CURRENT *A V £

FAULT CURRENT AND TRANSFORMER MAGNETIZING CURRENT WAVES

RELAY TYPE OUT CASE, APPROX (LEFT 4A

(8042544) RELAY TYPE OUT CASE, APPROX (RIGHT

GEK-45307

TARGETS C A l- I N U N I T INSTANTANEOUS

Ov6*CUtt NTU N I TlCAPACITOR Cl

OC CONTtOiVOLTAGE TAP LINKSAMPLIFIER CABO

RECTIFIER CABO HARMONIC BESTBAlNTADJUSTINGRHEOSTAT- R 2NCKUP ADJUSTING

RHEOSTAT - RlSLOPE ADJUSTINGRHEOSTAT - B 3

S BELAY

RATIO MATCHINGTAPS

FIG. ( 804253S) 3/4 FRONT VIEWSTD16C SIDE)

rBCACTOB II iv

BIACTOB 12

2vRECTIFIER CARD

THYBITE

RECTIFIER CARDTERMINAL BOARD

rr-CAFACITOB C2

SIDE)3/4 BACK VIEWFIR. 48 STulbC

!i

- - ( - _ - - - -

FIG. 7 (012881981-l) ELEMENTARY DIAGRAM FOR RELAYS FOR TRANSFORMER PROTECTION

27

GEK.-45307

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FIG. INTERNAL DIAGRAM FOR RELAY TYPE

SEK-453 C7

Cl J- rnroFREQ.

; OPER. R2

I SKJUWOWCL2 5 FREQ.

PRESTS.( INST. )

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CONNECTIONS10 ( 0257A 5026-0) STD15C

30

.

RELAY

l

.

I

010

ST:

I M I

RELAY

FIG. 12 (016582697-O) TEST CONNECTIONS

32

GEK-45307

LINESWIT04

SI +{D.C.115 K2LT

SU»PLY LOAO SUPPLY0BOXoAT RATEDFREQUENCY TARGET *SEAL- INA I

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LEGENDs INSTANTANEOUS OVERCURRENT UNITTARGET ANO SEAL- IN UNIT

S = TELEPHONE

DIAGRAM

GEK-45307

FIG. 13 OUTLINE OF TEST RECTIFIER

R A T E D

_ _ _

FIG. 14 FIELD TEST CONNECTIONS. CASE. USING TEST

8l?H0

ARRo£0ONTftcI'f BODY# 4-4d SCREWS

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•*M£U 1V ® s-

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RATEDFREQUENCY

TEST PLUOAC O—©IM 0.L *"?

si A.TEST CIRCUIT FOR STOI3C RELAYS

r-c5I LOAD BOX &T s3

TEST RECTIFIER RATED DC

^ CONTROL] VOLTSDCOI48A295BS| A 4A

LOAD BOX - S2 TEST PLUG6M3 VOLTS O—JAACFREQUENCY <&—c*1 INDICATINGLAMP

AS|

8. TEST CIRCUIT POR STDlfcC RELAYSPLUGTYPE XLAIN( 0257A5054-0 SH. 1)

33

SE; COOLED AIR COOLED

FIG. 17 USED IN SAMPLE CALCULATIONS

INTERNAL CDNNECTIW OF SENSE PRINTED CIRCUIT

35

GEK-45307

Y ^ 44 KV 600/5m A4 yyB4

Y4 FKA 1500-464110 KV600/5 *<Ayy4

& FK 439-115 < ' Y-< r» 13.0 KV< 600/5

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