Alternative Tests If Primary Injection Equipment Is Not Available; Check Of Fault Settings By Secondary Injection; Current Transformer Ratio And Polarity Tests - Siemens 7PG21 Solkor Rf Technical Manual

7PG21 Solkor Rf Commissioning
2.10 Alternative tests if primary injection equipment is not
available
If it is not possible to do the primary injection tests described under "Overall Fault Setting Tests" and "Current
Transformer Ratio and Polarity Tests" then the relay operation should be checked by secondary injection and the
C.T. ratio, polarity and the correctness of secondary connections should be checked using three phase load
current as described below.
When doing tests using three phase load current take care to ensure that the current transformer secondary leads
are never open circuited when current is passing through the primary.

2.10.1 Check of fault settings by secondary injection

Remove the trip links and C.T. earth links. With all the equipment including the pilots connected for normal
operation, arrange the test circuit as shown in Fig. 4. Slowly increase the test current until the local relay operates
and record the value of test current. Check that the relay operating current is approximately 11 milli-amperes and
that the current in the relay operating circuit at the remote end is of the same order.
If modern numeric test equipment is used, the requirements noted in section 2.1 Test equipment required, should
be observed.
Repeat the tests for the other earth fault conditions and also for the phase fault conditions. Tabulate the results as
shown in Table 3.
If it is convenient to permit operation of the circuit breaker at this stage, repeat one of the tests with the trip links
inserted. Increase the test current to the setting of the protection; the circuit breaker should then operate thus
proving the tripping circuit.
Repeat the tests at the other end of the feeder.

2.10.2 Current transformer ratio and polarity tests

Remove the trip links at both ends of the feeder. Connect ammeters in the current transformer secondary leads at
each end in turn, as shown in Fig. 5. Pass three phase load current through the primary and check the ratio of
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