Installation and Commissioning
280
7SS52 V4 Manual
C53000-G1176-C182-3
Figure 7-11 Test setup for the trip characteristic of the busbar-selective measuring system
Test steps
To prevent that the differential current supervision from blocking the protection dur-
ing the test switch it off with the parameter
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
(
XX13
/
CU
)
for the overcurrent thresholds for the affect-
ed bays to
0
.
The test currents I
1
and I
2
must have a phase displacement 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 must be nearly zero and the sta-
bilization current must be the double of the supply current.
If the differential current in not zero, check the connection. If that is correct reverse
the polarity in a feeder.
If the current I
2
is zero, then increase the current I
1
for so long until a TRIP com-
mand is output. The current in the feeder must correspond to the differential current
threshold set in the parameter
CU
).
Apply a constant current I
1
which is smaller than the set differential current thresh-
old to the feeder 1 from the test setup
Increase the current I
2
in feeder 2 slowly until the protection trips.
The following fomulas are valid:
Differential current I
d
=
| I
1
+
I
2
|
Stabilizing current I
s
=
| I
1
|
+
| I
2
|
Stabilizing factor k
=
I
d
/ I
s
=
| I
1
+
I
2
| / (| I
1
|
+
| I
2
|)
1 For testing the diff-current limit for supervisory function (refer to Chapter 7.3.3, page 268)
Note
The percentages of the differential and stabilization currents refer to Normalized Cur-
rent (Chapter 4.3.7, page 60). The percentages of the feeders refer to the transformer-
rated value of the particular feeder. If the same percentages are displayed this does
not mean necessarily that the same current is flowing in the concerned feeders.
www
. ElectricalPartManuals
. com
Содержание SIPROTEC 7SS522 V4.6
Страница 326: ...Maintenance and Repair 310 7SS52 V4 Manual C53000 G1176 C182 3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 432: ...Appendix 416 7SS52 V4 Manual C53000 G1176 C182 3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 438: ...Index 422 7SS52 V4 Manual C53000 G1176 C182 34 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...