ABB REL 356 Current Differential Protection
5-27
Testing
Current Differential Checks
The current differential checks will utilize load current to verify proper phase relationship at both ends of the line. The
OSCAR and RCP programs should be used to process and view the oscillographic records.
STEP 1
Use the actual settings or
C1 = 0.1
C2 = 0.7
C0 = 0.0
Make sure that LPBK = NO and ALDT = YES and that the relay displays CHRX = NORM.
STEP 2
Use the Display Select button to scroll down the Test Menu on the front of the REL 356. Use the RAISE button to scroll
to move through the functions until TEST appears in the window. With the tip of a pen, trigger an oscillographic record by
depressing the ENTER key on the front of the relay. Make sure you get a green VALUE ACCEPTED led indication.
STEP 3
In the RCP relay menu, go to Oscillographic Data <enter>. Select Analog and Digital data <enter>. Select record 0 (most
recent) <enter>. Wait for the program to download the record and save it to a file in a subdirectory of your choice.
STEP 4
Open the OSCAR program. Select Osc Data File <enter>. Select REL 356 <enter>. Find the .os6 file you saved in step
3 <enter>. Wait for the OSCAR program to calculate the analog and digital data in the saved file. Select Graph Osc Data
<enter>.
STEP 5
Now you will see the analog and digital data associated with this record.
Press F1 ANA MENU.
Press F3 SELECT MOVE DN.
Press F8 REMOVE TRACE and repeat until OP and RES are the two top traces on the screen.
Press F9 RETURN
Press F9 MAIN MENU
STEP 6
Repeat Step 4.
Read off the magnitudes for OP and RES displayed on the right side of the traces. OP should be close to zero while RES
should be two times the load current multiplied by the C1 setting.
(RES = |IL| + |IR| = 2 x I
load
x C1)
If the load current is low, this test can be performed with a temporarily higher C1 setting so that the RES waveform will
show in OSCAR, e.g. set C1 = 1.0 when taking the oscillographic record.
STEP 7
Verify at both line ends.
STEP 8
If the C1 setting was changed, return it back to actual setting.
STEP 9
Scroll the TEST menu on the front of the REL 356. Next scroll through the functions until the SRT function is displayed.
Verify that SRT = NO. This function stands for standing relay trip. If this is YES, it means that as soon as you close the
trip circuits, you will trip the breaker.
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
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