DIAC / DIFC / DSFC - GE Grid Solutions · ˘˘ˆ & 4 DIAC / DIFC / DSFC Digital Overcurrent Protection PRODUCT DESCRIPTION General The DIAC, DIFC and DSFC are a family of self-powered,
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CASE........................................................................................................................................................24ADJUSTMENTS ..........................................................................................................................................24TARGETS AND INDICATORS........................................................................................................................24RESET AND MANUAL TRIP .........................................................................................................................25TRIP CIRCUIT TEST ...................................................................................................................................25TRIP CIRCUIT ............................................................................................................................................25COVER INSTALLATION DIAC AND DSFC.....................................................................................................25RECEIVING, HANDLING AND STORAGE .......................................................................................................25
IOC/TOC UNIT .........................................................................................................................................43
Cover Photo: 8919670
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2 DIAC / DIFC / DSFC Digital Overcurrent Protection
LIST OF FIGURES
FIGURE 0: FRONT VIEW DIFC (8919654)................................................................................................................... 3
FIGURE 16: I2T TIME CURVE .................................................................................................................................... 21
FIGURE 17: IOC CURVE............................................................................................................................................ 22
FIGURE 18: DIAC AND DSFC EXTERNAL / INTERNAL CONNECTIONS............................................................... 27
FIGURE 32: IOC/TOC UNIT ....................................................................................................................................... 43
These Instructions do not purport to cover all details or variations in equipmentnor provide for every possible contingency to be met in connection with the in-stallation, operation, or maintenance. Should further information be desired orshould particular problems arise which are not covered sufficiently for the pur-chaser’s purpose, the matter should be referred to the GENERAL ELECTRICCOMPANY. To the extent required the product described herein meets applicableANSI, IEEE, NEMA, and IEC standards; but no assurances are given with respect tolocal codes and ordinances because they vary greatly
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DIAC / DIFC / DSFC Digital Overcurrent Protection 3
INTRODUCTION
Figure 0: Front View DIFC (8919654)
FEATURES• Digital single Phase overcurrent protection• General-purpose feeder protection• 50 / 51 applications• Self-powered• 16 Selectable curves• Reset curve enable/disable• Low Burden• Fully Retrofitable *• Functional separate TOC and IOC opera-
tions.• Wide settings range.• Drawout case construction
* When replacing unit and case (see instructionmanual INSTALLATION section for details).
51
52
50
Main Bus
To Load
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4 DIAC / DIFC / DSFC Digital Overcurrent Protection
PRODUCT DESCRIPTIONGeneral
The DIAC, DIFC and DSFC are a family of self-powered, single-phase, digital overcurrent relays.The DIAC is packaged in a GE S1 style case, theDIFC is packaged in a GE C1 style case and theDSFC is packaged in a GE V1 style case. See theHARDWARE DESCRIPTION section for mountingdimensions.
The table below gives the model number break-down.
D_ _CA _ _
B Revision
1 1 Amp Nominal Current
5 5 Amp Nominal Current
IF C1 case
IA S1 case
SF V1 case
These relays use waveform sampling of the currentinput together with appropriate algorithms to pro-vide a time overcurrent (TOC) and an instantane-ous overcurrent (IOC) function.
Application
Time and instantaneous overcurrent functions arewidely used in many applications throughout thepower system. Typical examples are protection ofutility and industrial feeders and short circuit andoverload protection for transformers, and motors.
For feeder protection, the usual application re-quires one relay per phase and a fourth relay con-nected in the residual circuit of three ‘wye’ con-nected current transformers (CTs). A typical exter-nal connection diagram for this application isshown in Figure 18 OR 19. Use of a separateground relay provides more sensitive protection forground faults.
The TOC reset characteristics can be set to emu-late those of an induction disk or set for fast resetwith no intentional delay.
Functions
The TOC function operates on an ‘RMS’ currentcalculated from the sampled values. The IOC func-tion operates on the sampled values, and the algo-rithm virtually eliminates the decaying DC offset
component to achieve low transient overreach ofless than 7%.
The relays contain two independent settings, onefor TOC and one for IOC.
TOC
The TOC function provides 16 selectable time cur-rent curves.
• IAC51
• IAC53
• 55-SHORT TIME
• 57-MEDIUM TIME
• 66-LONG TIME
• 75-SHORT TIME
• IAC77
• 95-SHORT TIME
• IEC Inverse
• IEC Very Inverse
• IEC Extremely Inverse
• IEEE Inverse
• IEEE Very Inverse
• IEEE Extremely Inverse
• Definite Time
• I2T
The IAC51, IAC53 and IAC77 curves match thetime current curve of the respective IAC model.This includes the 0.5 through 9.9 time dial settingand for both the 1 and 5 amp units. Numberedcurves 55, 57, 66, 75, and 95 match the shape ofthe respective IAC model however the time dialpositions are not one to one equivalents. The IEC,IEEE and I2t curves are based on the followingequations:
NOTE:
••••••••••••••••••••••••••••••••••
IEC equations are defined by IEC 255-4 and IEEEequations are defined by IEEE PC37.112
••••••••••••••••••••••••••••••••••
In the following equations,
M = multiple of pickupTD = time dial (0.5, 1, …, 9.9)t = time (seconds)
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DIAC / DIFC / DSFC Digital Overcurrent Protection 5
IEC Inverse
See Figure 9 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
−=
−
−=
−
1014.0
197.
02.0
2
IEC Very Inverse
See Figure 10 for graph of equation
TDM
t
timePickup
TDM
t
−=
−
−=
−
135.1
132.4
1
2
timeReset
IEC Extremely Inverse
See Figure 11 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
−=
−
−=
−
10.8
182.5
2
2
IEEE Inverse
See Figure 12 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
+
−=
−
−=
−
0228.01
0103.
197.
02.0
2
IEEE Very Inverse
See Figure 13 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
+
−=
−
−=
−
0982.01
922.3
132.4
2
2
IEEE Extremely Inverse
See Figure 14 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
+
−=
−
−=
−
02434.01
64.5
182.5
2
2
I2T
See Figure 16 for graph of equation
TDM
t
timePickup
TDM
t
timeReset
=
−
=
−
2
2
250
2
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6 DIAC / DIFC / DSFC Digital Overcurrent Protection
0.1 2 3 4 55 6 7 1 2 3 4 55 6 10 2 3 4 55 6 100
0.1
2
3
4
5
66
7
1
2
3
4
5
66
7
10
2
3
4
5
66
7
100
DIAC, DIFC, & DSFC OVERCURRENT RELAYS
IAC 51
RESET OPERATE
.5
1
2
3
4
567899.9
Tim
e D
ial S
ettin
gs
Inverse Standard
���Pow er M anagem ent
Frequency: 50/60 Hertz
0.1 - 3.18 (1 Ampere Relays)General Electric CO., 205 Great Valley Parkway, Malvern, PA 19355
22 DIAC / DIFC / DSFC Digital Overcurrent Protection
The I2T curve has a K value equal to the time dial times 250. The minimum value of K is 25 (0.1 times250) and the maximum value is 2475 (9.9 times 250).
Multples of Pickup Setting
2
3
4
5
6
7
8
9
100
Tim
ein
Mill
ise
co
nd
s
1 2 3 4 5 6 7 8 9 10
OVERCURRENT RELAYS
DIAC, DIFC, & DSFC
Instantaneous
1.51.1
GES10039
Current Range: 0.5 - 15.9 ( 5 Ampere Relays)
0361A7503
0.1 - 3.18 (1 Ampere Relays)
Frequency: 50/60 Hertz
Power Management
Figure 17: IOC Curve
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DIAC / DIFC / DSFC Digital Overcurrent Protection 23
CALCULATION OF SETTINGS
When replacing IAC, IFC or SFC relays, reviewthe time current curves of the digital relays toverify that they conform to the relays being re-placed. In some cases it may be necessary toredo the coordination study to assure coordina-tion with other devices.
The base time of the Definite Time Curve is 1second. The base time is multiplied by the timedial to provide the actual operating time. Thedefault or lowest time dial setting for the DefiniteTime Curve is 0.1.
The I2T curve has a K value of 250 @ time dialof 1. The range is from 25 to 2475 in steps of 25set by the time dial. The default or lowest timedial setting for the I2T curve is 0.1.
TOC pickup is settable from 0.5 to 15.9 amps in0.1 amp increments for the 5 amp model, and0.1 to 3.18 amps in 0.02 amp increments for the1 amp model, a setting of 0 disables the TOCelement. The time dial can be set from 0.5 to 9.9in 0.1 increments on both the 5 amp model and
the 1 amp model. The only exception is for theDefinite Time and I2T curves where 0.1 is theminimum value.
The IOC function is settable from 1 to 159 ampsin 1 amp increments for the 5 amp model, and0.2 to 31.8 amps in increments of 0.2 amps forthe 1 amp model. Setting the pickup to 0 dis-ables the IOC element. Both models have anIOC delay adjustment from 50 to 400 millisec-onds in 25 millisecond steps.
The formula: IOC delay in milliseconds = DS x25 + 25, where DS is setting on IOC delay dial.
The TOC reset characteristic can be controlledfrom the front panel. The TOC reset can be setto “timed reset” which emulates the characteris-tic of an induction disk relay, or “instantaneousreset” where the reset is fixed at 40 to 50 milli-seconds.
The system frequency can be set for 50 or 60 Hzcontrolled from the front panel.
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24 DIAC / DIFC / DSFC Digital Overcurrent Protection
HARDWARE DESCRIPTION
Case
DIAC and DSFC
The DIAC and DSFC relays consist of a case,cover, support structure, and a connection plugto make up the electrical connection. The case isshown in Figures 20 and 22. The external con-nections are shown in Figure 18. It has 10 con-nection points and a CT shorting bar. As theconnection plug is withdrawn the trip circuit isbroken prior to the current shorting bar engage-ment. The window provides visual indication ofthe CT shorting.
DIFC
The DIFC relays consist of a molded case,cover, support structure, and a connection plugto make up the electrical connection. The case isshown in Figures 20 and 21. The external con-nections are shown in Figure 19. It has 14 con-nection points and a visible CT shorting bar. Asthe connection plug is withdrawn the trip circuit isbroken prior to the current shorting bar engage-ment. The window provides visual indication ofthe CT shorting.
Adjustments
All customer settings are accessible from thefront of the relay. The cover must be removed togain access to the settings. The cover has provi-sions for a sealing “wire.” The settings are left toright, pickup current level for the time element,time dial, curve selection, frequency / reset time,pickup current level for the instantaneous ele-ment, and the instantaneous element time delay.The settings are all calibrated and are set byturning the rotary switch to the desired value.The switches are recessed; a small screwdriveris required to make the adjustment.
The relay may be supplied with one of threepointer styles as shown. The color is the color ofthe indicator, note the arrow location, allswitches are shown in the 9:00 position.
The TOC pickup current is set directly in Ampswith two rotary switches. An arrow is used to in-dicate setting position. Setting the TOC or theIOC pickup current between, but not including 0and a value less than minimum 0.5 (5 amp) or0.1 (1 amp) will result in the relay defaulting to itsminimum setting. Setting the TOC or IOC pickup
current to 0 will disable their respective ele-ments. Although the time dial can be set to avalue less than minimum the relay will use theminimum setting.
The relay also provides a front panel trip circuittest. An actuating lever that must be pulled andthen lifted is provided to trip the device con-nected to the relay. The level directly operatesthe trip contacts.
3RLQWHU VW\OHV
<HOORZ 2UDQJH :KLWH
Targets And Indicators
The yellow pick-up LED will come on solid for theTOC function when the input current to the relayis higher than the set point. The location of theLED is between the frequency/reset switch andthe IOC pickup level switch.
It may be desirable to know when the relay ispowered up and operating. The relay must beenergized at or above 95% of the minimum pos-sible setting and below pick-up set point. To ac-tivate, turn the SELECT switch one step clock-wise or one step counterclockwise. This willcause the pickup LED to blink at 4 second inter-vals while current is below the pick-up set point.Minimum current is 95% of minimum TOCpickup setting for both the 1amp and 5 ampmodels. A blinking LED indicates the microproc-essor is executing code and outputting signals.
The relay uses a target and seal-in unit as itstripping element. The relays have one TOC tar-get and one IOC target. The targets are me-chanically latched when the function trips. Thetrip contacts will remain closed until the trip cir-cuit current drops below 0.19 A.
NOTE: Do not attempt to reset the trip targetwhile DC is still applied – this may damagethe output contact.
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DIAC / DIFC / DSFC Digital Overcurrent Protection 25
Reset And Manual Trip
Targets can be reset by depressing the frontcover target reset button for the DIFC or liftingthe target reset level at the lower left edge of thecover on the DIAC and DSFC.
Trip Circuit Test
The front panel contains two manual trip leversto test the trip circuit. The relay cover must beremoved to access the lever. The lever must bepulled and then lifted which prevents uninten-tional uplifted to prevent unintentional operation.
Trip Circuit
CAUTION: The trip circuit is polarity sensi-tive. The trip circuit will not be damaged ifconnected in reverse. However, it will not tripthe associated breaker. The trip circuit isconfigured to have the positive battery ter-minal connected to Stud 1 for the TOC andIOC trip circuit and the negative to Stud 2(TOC) and Stud 3 (IOC).
NOTE: Both trip circuits are suitable for usewith Cap-Trip devices.
Cover Installation DIAC and DSFC
NOTE: When replacing the cover on the DIACand DSFC relays the reset wire should be“locked” behind the nameplate by a slight left toright motion to place the reset wire in the correctposition.
Receiving, Handling And Storage
Immediately upon receipt, the relay should beunpacked and examined for any damage sus-tained during shipment. If damage occurredduring shipment a damage claim should be filedat once with the transportation company, and thenearest GE sales office should be notified. If therelay is not installed immediately, it should bestored in its original carton in a location that isdry and protected from dust, metallic chips andsevere atmospheric conditions.
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26 DIAC / DIFC / DSFC Digital Overcurrent Protection
INSTALLATION
Environment
Installation of the relay should be in a clean drylocation that is free from dust.
Mounting
The relay should be securely mounted on a ver-tical surface that provides accessibility to boththe front and rear of the unit. The outline andpanel drilling dimensions are provided in figures20, 21, 21A, and 22 for each stile case. An addi-tional surface mounting option is available for theDIFC relay.
Surge Ground (DIAC and DSFC)
The relay should be grounded to the stationground mat with a 12 AWG braided ground leadconnected to terminal 4. If the relay is to beretrofitted in a panel, terminal 4 should beremoved from the new case and installed intothe old case. For the surge protection to functionproperly the relay must be grounded.
Surge Ground and RFI Immunity(DIFC only)
The relay should be grounded to the stationground mat with a 12 AWG braided ground leadconnected to Terminal 4 when replacing IFCrelays. The IFC relay and case must be removedand replaced with the DIFC relay and case.
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DIAC / DIFC / DSFC Digital Overcurrent Protection 27
Figure 18: DIAC and DSFC External / Internal Connections
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28 DIAC / DIFC / DSFC Digital Overcurrent Protection
Figure 19: DIFC External / Internal Connections
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DIAC / DIFC / DSFC Digital Overcurrent Protection 29
6.625
PANEL
CASE
.75
3.0
STUDNUMBERING
13579
10 8 6 4 2
6.187
5.687
2.187
4.375 8.812CUTOUT
.500
(TYPICAL)
5.25
5/8 DRILLCUTOUT MAY REPLACE
DRILLED HOLES
PANEL LOCATION
GLASS
(4) 10-32 X 3/8
MTG. SCREWS
.218
2 HOLES
1.46837MM
133MM 12MM
3/4 DRILL10 HOLES
5MM
224MM
56MM
112MM
168MM
29MM 19MM
157MM
9.125232MM
4.406112MM
3.90699MM
76MM
1.125
144MM
BACK VIEW
CL
LC LC
15MM
19MM
MTG.MTG.SEMI-FLUSH SURFACE (2) 5/16-18 STUDS
FOR SURFACE MTG.
10-32STUDS
8.375212MM
76MM
TYPICAL DIM.
INCHESMM
VIEW SHOWING ASSEMBLY OF HARDWAREFOR SURFACE MTG. ON STEEL PANELS
PANEL DRILLINGFOR SEMI-FLUSH MOUNTING
FRONT VIEW
5/16-18 STUD
PANEL DRILLINGFOR SURFACE MOUNTING
FRONT VIEW
1/4 DRILL4 HOLES6MM
2.84372MM
1.15629MM
109MM
.2506MM
3.076MM
.71818MM
4.281
3.0
5MM.218
Figure 20: DIAC Panel Mounting and Drilling
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30 DIAC / DIFC / DSFC Digital Overcurrent Protection
RELAY
FRONT VIEW
3.688
6.062
3.062
6.124
1
214
13
CUTOUT
REAR VIEW
MOUNTING SURFACE
10-32 SCREWSCONNECTIONSEXTERNAL
C
C
C
C
C
SIDE VIEW
7.563
SEE VIEW "B"
(2) .750 HOLES
4.750
2.375
.250
2.000
5.00
NUMBERINGSTUD
SIDE VIEW
EXTERNALCONNECTIONS10-32 SCREWS
MOUNTING SURFACE
SEE VIEW "C"
C
C
3.688
SURFACE MOUNTING FOR.188 (5MM) THK.
SURFACE MOUNTING FOR
2.375
4.750
.469
.156
.625 TYP.
PANEL DRILLING
REFER TO RELAY FORQUANTITY OF HOLES.
.750
.625
NUT
HDW. 0257A8549-G2VIEW "C"
REMOVE KNOCKOUT
8-36SCREW
WASHER
MOUNTINGSURFACE
LKWASH
SURFACEMOUNTING
WASHER
8-36
VIEW "B"HDW. 0257A8549-G2
NUT
( 2) . 219 HL S
SPACER
L OCK WASHER
SCREWREMOVE KNOCKOUT
OVERSIZE WASHERS
2.500
8.344
.188 (5MM) THK. MAX. PANEL
F OR . 312 HL S
7.376187MM
94MM
154MM
PANEL DRILLING
5.562141MM
71MM2.7813.031
77MM
156MM
78MM
192MM
61MM
121MM
19MM
7MM
51MM
64MM
128MM
212MM
94MM
12MM
19MM
16MM
16MM
8MM4MM
5MM
61MM
121MM
AND OVER.AND OVER.
Figure 21: DIFC Panel Mounting and Drilling
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DIAC / DIFC / DSFC Digital Overcurrent Protection 31
RELAY
FRONT VIEW
3.688
6.062
3.062
6.124
1
214
13
CUTOUT
REAR VIEW
MOUNTING SURFACE
10-32 SCREWSCONNECTIONSEXTERNAL
C
C
C
C
C
SIDE VIEW
7.563
SEE VIEW "B"
(2) .750 HOLES
4.750
2.375
.250
2.000
5.00
NUMBERINGSTUD
SIDE VIEW
EXTERNALCONNECTIONS10-32 SCREWS
MOUNTING SURFACE
SEE VIEW "C"
C
C
3.688
SURFACE MOUNTING FOR.188 (5MM) THK.
SURFACE MOUNTING FOR
2.375
4.750
.469
.156
.625 TYP.
PANEL DRILLING
REFER TO RELAY FORQUANTITY OF HOLES.
.750
.625
NUT
HDW. 0257A8549-G2VIEW "C"
REMOVE KNOCKOUT
8-36SCREW
WASHER
MOUNTINGSURFACE
LKWASH
SURFACEMOUNTING
WASHER
8-36
VIEW "B"HDW. 0257A8549-G2
NUT
( 2) . 219 HL S
SPACER
L OCK WASHER
SCREWREMOVE KNOCKOUT
OVERSIZE WASHERS
2.500
8.344
.188 (5MM) THK. MAX. PANEL
F OR . 312 HL S
7.376187MM
94MM
154MM
PANEL DRILLING
5.562141MM
71MM2.7813.031
77MM
156MM
78MM
192MM
61MM
121MM
19MM
7MM
51MM
64MM
128MM
212MM
94MM
12MM
19MM
16MM
16MM
8MM4MM
5MM
61MM
121MM
AND OVER.AND OVER.
Figure 22: SURFACE MOUNTING DIFC
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32 DIAC / DIFC / DSFC Digital Overcurrent Protection
6.625
PANEL
CASE
.75
3.0
STUDNUMBERING
13579
10 8 6 4 2
6.187
5.687
1.125
2.25 6.687CUTOUT
.500
(TYPICAL)
5.25
5/8 DRILLCUTOUT MAY REPLACE
DRILLED HOLES
PANEL LOCATION
GLASS
(4) 10-32 X 3/8
MTG. SCREWS
.218
2 HOLES
1,46837MM
133MM 12MM
3/4 DRILL10 HOLES
5MM
169MM
28MM
57MM
168MM
29MM 19MM
157MM
7177MM
3.34384MM
2.84472MM
76MM
1.125
144MM
BACK VIEW
CL
LC LC
15MM
19MM
MTG.MTG.SEMI-FLUSH SURFACE (2) 5/16-18 STUDS
FOR SURFACE MTG.
10-32STUDS
5.625142MM
76MM
TYPICAL DIM.
INCHESMM
VIEW SHOWING ASSEMBLY OF HARDWAREFOR SURFACE MTG. ON STEEL PANELS
DIAC / DIFC / DSFC Digital Overcurrent Protection 33
ACCEPTANCE TESTS
Immediately upon receipt of the relay, aninspection and acceptance test should be madeto make sure that no damage has beensustained in shipment, and that the relaycalibrations have not been disturbed.
Visual Inspection
Check the nameplate stamping to make surethat the model number and rating of the relayagree with the requisition. Remove the relayfrom its case and check that there are no brokenor cracked molded parts or other signs ofphysical damage, and that all screws are tight.
Mechanical Inspection
1. The target and seal-in unit, pull and liftthe TOC lever to test the target, repeatthe test for the IOC target. The Targetflag should remain when the lever is re-leased. Reset the target by pushing thereset bar.
2. Make sure that the fingers and shortingbars agree with the internal connectionsdiagram.
CAUTION: Every circuit in the drawout casehas an auxiliary brush. It is especially impor-tant on current circuits and other circuitswith shorting bars that auxiliary brush bebent high enough to engage the connectionplug or test plug before the main brushes do.This will prevent CT (current Transformer)secondary circuits from being opened.
Electrical Tests
DRAWOUT RELAYS, GENERAL
Since all drawout relays in service operate intheir cases, it is recommended that they betested in their cases or an equivalent case. Arelay may be tested without removing it from thepanel by using the appropriate test plug. For a Ccase, use the XCA test plug; for a V or S case,
use the XLA series test plug (refer to the GEPower Management Product Catalog). Althoughthe test plugs provide greater flexibility, it re-quires C.T. shorting jumpers and exercise ofgreater care since connections are made to boththe relay and the external circuitry.
INVERSE TIME UNIT
Pickup Verification
• Connect the relay as indicated in Figure 24or 25. In order to apply current to the relay,use a 50/60 Hz voltage source, with a vari-able resistor in series, or an electronic cur-rent source.
• Set the relay at the desired pickup TOC anddisable the instantaneous unit by setting theinstantaneous current setting to zero (0).
Apply current to the relay and verify that thePickup LED on the front of the relay lights be-tween 98% and 102% of the pickup TOC setting.If the relay is set to blink between power up andpickup, look for the LED to be on most or all ofthe time to indicate pickup.
Reduce the current applied, verifying that at avalue between 95% and 100% of the pickupTOC, the relay Pickup LED turns off or blinks ifset to blink.
Verification of Operating Time
Because the Digital self powered series of relayshas many different curve characteristics, thebasic test instruction will be given and the datafor each of the curves can be found in Table 1.With the relay still connected as indicated inFigure 24 or 25, set the time overcurrent unit tominimum pickup and set the corresponding timedial to 5. Successively apply currents of 2, 5, and10 times pickup TOC, verifying that the operatingtimes are within the margins indicated in Table 1.
NOTE: Before attempting to reset the triptarget, ensure the DC supply is removed orturned off from the trip circuit setup
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34 DIAC / DIFC / DSFC Digital Overcurrent Protection
Note: Time measured in seconds
Table 1: Pickup Times for Varying Multiples of Pickup (MPU)MPU
DIAC / DIFC / DSFC Digital Overcurrent Protection 35
For the Definite Time Characteristics, based onany current input, the time should be half of themaximum value.
Verification of Time Dial
Set the relay at the minimum pickup TOC andverify that with an input current of five times (5x)pickup TOC, the operating time is between themargins shown in Table 2.
36 DIAC / DIFC / DSFC Digital Overcurrent Protection
INSTANTANEOUS UNIT
The Instantaneous unit is designed similarly to ahinged armature instantaneous unit. Theinstantaneous unit will react differentlydepending on how the signal is applied. If thesignal is applied suddenly with no prefaultcurrent, the operating time will be longer. If aprefault current is applied prior to the fault theoperating time will be shorter. The following testdetermines that the instantaneous unit is workingcorrectly and confirms the operating time forfaults applied with no prefault current.
Connect the relay as shown in Figure 26 or 27,Set the instantaneous unit pickup to 2 amps (5amp rated relay) or 0.4 amps (1 amp rated relay)with a zero IOC delay setting. Apply 6 amps (5amp rated relay) or 1.2 amps (1 amp rated relay)and measure the operating time. The operatingtime should be between 32 ms and 46 ms. Thistime is subject to dependent on the multiple ofpickup current and the fault incidence angle. Agraph of how the instantaneous unit varies as afunction of input current is provided in this bookfor reference, Figure 17.
Target andSeal-in
AUX TOC
contact
T11
T12
T2
T1
Iin
T5
T6
Single Phase
Current Source
Start StopTIMER
– Negative
36/300VDCPower Supply
Current Limited to200 mA
+ Positive
Figure 24: DIFC Test Setup for Pickup and Operating Time Verification
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DIAC / DIFC / DSFC Digital Overcurrent Protection 37
Target andSeal-In
AUX TOCContact
T7
T8
T2
I in
T5
T6
Single PhaseCurrent Source
Start StopTIMER
- Negative
36 / 300 V DCPower Supply
Current Limited to200 mA
+ Positive
Figure 25: DIAC or DSFC Test Setup for Pickup and Operating Time Verification
Target andSeal-In
AUX TOCContact
T7
T8
T2
I in
T5
T6
Single PhaseCurrent Source
Start StopTIMER
- Negative
36 / 300 V DCPower Supply
Current Limited to200 mA
+ Positive
Figure 26: DIFC Test Setup for Instantaneous Unit
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38 DIAC / DIFC / DSFC Digital Overcurrent Protection
Target andSeal-In
AUX TOCContact
T7
T8
T2
I in
T5
T6
Single PhaseCurrent Source
Start StopTIMER
- Negative
36 / 300 V DCPower Supply
Current Limitedto 200 mA
+ Positive
Figure 27: DIAC or DSFC Test Setup for Instantaneous
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DIAC / DIFC / DSFC Digital Overcurrent Protection 39
PERIODIC TESTS AND SERVICING
Periodic Tests
It is recommended that the user perform aperiodic test to verify that the relay is operatingproperly. It is recommended that a portion of theacceptance tests be performed to verify therelay. An inspection of the seal-in contacts canbe performed by removing the relay from itscase and visually inspecting the contacts forcorrosion.
Servicing
If the relay fails to perform as specified in thisinstruction manual consult the factory or call yourlocal GE sales office. Before returning the relayconsult with the factory’s technical support.
It is not recommended that the relay be servicedto the component level. This requires substantialinvestment in repair/test equipment and intechnical expertise, and usually results in alonger down time than if a spare relay were usedin its place, while the unit is shipped back to thefactory.
Figure 28 (9819647/8919648): DIAC Front and Rear Views
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40 DIAC / DIFC / DSFC Digital Overcurrent Protection
Figure 29 (8919652/8919653): DIFC Front and Rear Views
Figure 30 (8919632/8919661): DSFC Front and Rear Views
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DIAC / DIFC / DSFC Digital Overcurrent Protection 41
SPECIFICATIONS
Burdens
Burdens for the over-current units are listed in Table 3. Burdens decrease with increasing current aboveminimum setting, due to the power supply shunting in the power supply circuit. Since the power supply isthe major portion of the burden, the burden for a given input current will be constant, irrespective of pick-up settings on both TOC and IOC units.
Table 3: Burden Settings
Burden @ Minimum Setting Burden in ohms (Z) at multiples ofminimum pickup
0.1 - 3.18 (1 Ampere Relays)General Electric CO., 205 Great Valley Parkway, Malvern, PA
0361A7504
Input Current
Current Range: 0.5 - 15.9 ( 5 Ampere Relays)
GES10040
Bu
rde
n in
VA
Figure 31: Burden curve
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42 DIAC / DIFC / DSFC Digital Overcurrent Protection
RatingsFrequency: 50 / 60 HzCurrent: 1A or 5A ModelsMaximum Permissible Current, 1 A Model: Continuous: 3 A 3 seconds: 50 A 1 second: 100 AMaximum Permissible Current, 5 A Model: Continuous: 15 A 3 seconds: 250 A 1 second: 500 AOperating Current Range, 1 A Model minimum: 0.095 A I2T (constant): 1520Operating Current Range, 5 A Model minimum: 0.475 A I2T (constant): 38000Maximum Transient Overreach: 7%
Burdens0.1/0.5 A (1/5A unit): 0.475 VA1.0/5 A (1/5A unit): 2.6 VA
See Figure 31 for curve and Table 3 for settings.
Contact RatingsOutput Contacts:
Vol
tage
Con
t.
Mak
e an
d ca
rry
1 se
c.
Bre
ak
Max
load
DCResistive
125V250V
10A 30A 0.5A0.3A
60W
DCInductive
L/R=40ms
125V250V370V
10A 30A 0.25A0.15A0.05A
50VA
NOTE: Suitable for Cap-Trip devices.
EnvironmentalAmbient Temperature: Storage: 40 to 85°C Operation: –40 to 70°C Humidity: Up to 95% without
Surge Withstand CapabilityFast Transient: per ANSI C37.90.1 and
IEC 255-22-4 Class IVOscillatory: per ANSI C37.90.1 and
IEC 255-22-1 Class IV
Radio Frequency Withstand25 MHz to 1 GHz keyed every 1 MHz for 2 sec.;per ANSI C37.90.2 andIEC 255-22-3
Electrostatic DischargePer: IEC 225-22-2
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DIAC / DIFC / DSFC Digital Overcurrent Protection 43
APPLICATION NOTES
IOC/TOC Unit
The relay has one TOC target and one IOC tar-get and uses a seal-in unit as its tripping ele-ment. The trip contact remains closed until thetrip circuit drops below 0.19 A. A breaker contact
(52a) can be provided in series with the trip cir-cuit to reset the target once the breaker trippedon fault.