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Installation_Guide_SIAB000B0010AA_Rev. 03 26 / 32
8.3. Measurements
The accuracy of the measurement depends on the CT type:
-
With CTxx-5 type
< ± 5%.
-
With CTxx-10 type
< ± 10%
The relay is able t measure up to 20 times the maximum nominal current of the CT.
8.4. Protection functions
Current injection procedure:
As an example the nominal current (Is) adjusted in general settings will be 16 amperes and the
CT type will be CT16. Adjust the Sverker current injector with HOLD 0,8xIsmin, and suddenly,
inject it to the relay, as it would happened in real situation when circuit breaker is close,
powering network line. From this value, increase the current to achieve the function pick-up and
the function trip.
8.4.1. Protection functions testing
NOTE
:
The followig testing processes will be done with the specific CTs 5P80. So in this
case, the measurement accuracy will be ±5%.
•
50P instantaneous phase overcurrent protection:
Settings:
-
Permission: YES.
-
TAP: 1xIs=16 A
-
Theoretical tripping time: 2 (sec)
-
Tripping time range: 1,9…2,1 s.
The following information will be checked:
-
Pick-up at 100% of the tap
-
Trip output is activated
-
Trip flag is activated
•
50N instantaneous neutral overcurrent protection:
Settings:
-
Permission: YES.
-
TAP: 1xIs=16 A
-
Throretical tripping time: 2 (sec)
-
Tripping time range: 1,9…2,1 s.
The following information will be checked:
-
Pick-up at 100% of the tap
-
Trip output is activated
-
Trip flag is activated
