Subject to change without notice. Printed matter No. ZR-CR03E Doc. CR033089BE V01 2015
SVERKER900
Relay and Substation Test System
Current transformer testing
This application note gives examples on how to
perform some typical tests on current transformers
(CTs) with SVERKER 900. These tests are common to
perform for instance during commissioning.
Important
Read and comply with the safety instruc-
tions in the User's manual.
Test procedures
Tests to be done at commissioning
▪ Wiring check and visual inspection
▪ Polarity test with DC current or AC voltage
▪ Burden impedance test
▪ Magnetization curve test
▪ Primary injection test with load connected
Other tests
▪ Secondary resistance test (RCT)
▪ Primary injection - Ratio test with AC current or voltage
(no load connected)
Required equipment for testing
▪ SVERKER 900
Wiring check and visual inspection
1] Check that the primary and secondary side
are connected for correct ratio according to
system requirements.
2] Check the tightness for secondary connec-
tions, including grounding and shorting links.
3] Check that each core is connected to correct
load according to drawings.
4] Check that each core are grounded in only
one point on secondary side and close to
CT location. For CT secondaries connected
together the grounding shall be done at
relay point, for exampel cores connected to
differential protection.
Current transformer data
Relay core 5P and 10P
Measuring core 0.3 B
n Accuracy limit factor (ALF) for relay cores
Safety factor (SF) for measuring cores
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