Installation and Commissioning
282
7SS52 V4 Manual
C53000-G1176-C182-3
Figure 7-13 Test setup for the trip characteristic of the check zone.
Test steps  Prevent the differential current supervision from blocking the protection during the
tests switch it off with the parameter DIFF SUPERV (6306/CU).
 Set the differential current threshold and the stabilization factor for the busbar-se-
lective protection and the check zone as desired.
 Set the parameters I>TRIP (XX13/CU) for the overcurrent limits for the affected
bays to 0.
 The test current I
1
in bay unit 1 and 2 must have a phase shift of 180°. To find out
the phase angle, check the feeders 1 and 2 each with the same current (0,5 I
N
).
 If the connection is correct the differential current of the bus zone must be nearly
zero and the stabilization current must be the double of the supply current.
 If the differential current is not zero, reverse the polarity in a feeder.
 If the current I
1
is zero, increase the current I
2
until the annunciation Trip L1 CZ
to Trip L3 CZ (FNo. 10457 to 10459/CU) is output by the measuring system
which is assigned to bay 3. The current I
2
must correspond to the differential current
threshold set in the parameter Id> CZ (6104/CU).
 Apply to the bays 1 and 2 of the test setup with a constant current I
1
.
 Increase the current I
2
in bay 3 slowly until the protection trips. The differential cur-
rent is then I
2
and the stabilizing current I
1
(Chapter 5.2, page 112). The stabilizing
factor k is then equal to the ratio of I
2
to I
1
.
 Repeat the test with different constant currents I
1
. The trip characteristic graph is
shown in Figure 7-12, page 281.
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