Installation and Commissioning
284
7SS52 V4 Manual
C53000-G1176-C182-3
7.4.3.2 Check Zone
To test the check zone, the check zone must be set more selective than the busbar-
selective protection so that the supervision of the check zone picks up earlier.
Example You want to test the supervision of the check zone with the parameters for the differ-
ential current threshold Id> SUPERV CZ (6309/CU) = 0,2 I/I
no
and the delay time
T-Idiff SUPERV (6307/CU) = 2,0 s. For the busbar-selective protection the param-
eter Id> SUPERV BZ (6308/CU) is assumed to be set to 0,8 I/I
no
.
Test setup
 Arrange the test setup as in Chapter 7.4.2, page 279.
Test steps Check of the pickup threshold and the delay time:
 Increase the current in feeder 1 slowly until the check zone supervision picks up.
The measured current must correspond to the set current
Id> SUPERV CZ (6309/CU).
 Carry out a time measuring as in Chapter 7.4.3.3, page 284
Checking the blocking:
 The reaction of the protection when the differential current supervision of the check
zone picks up can be set with the parameter DIF SUP mode CZ (6311/CU) to
blocking or to only indicate (without protective blocking).
 Connect the bays 1 and 2 to the same bus zone.
 Increase the current in feeder 1 slowly until the supervision of the check zone picks
up.
 Apply to feeder 2 a current 4 times as high as the rated current I
N
. If the parameter
is set DIF SUP mode CZ (6311/CU) to blocking, no TRIP commands follow.
7.4.3.3 Time Delay
Time measuring is possible with the standard test equipment for protection devices.
 To measure the delay time for the differential current supervision, apply to feeder 1
through the testing device twice the current set in the parameter differential current
threshold Id> SUPERV BZ (6308/CU).
 As soon as the differential current supervision picks up, the test current source is
switched off. The measured time corresponds to the set delay time in parameter T-
Idiff SUPERV (6307/CU).
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