17
Secondary
injection testing
Relay testing, both primary and secondary,
should always be performed in accordance with
national regulations and instructions.
The protection relay incorporates an IRF func-
tion that continuously monitors the internal
state of the relay and produces an alarm signal on
detection of a fault. According to the manufac-
turer’s recommendations the relay should be
submitted to secondary testing at five years’
intervals. These tests should include the entire
protection chain from the instrument trans-
formers to the circuit breakers.
The secondary testing described in this manual
is based on the relay’s setting values during
normal operation. If necessary, the secondary
testing can be extended by testing the protection
stages throughout their setting ranges.
As switch positions and setting values have to be
altered during the test procedure the correct
positions of switches and the setting values of
the relay during normal operation conditions
have to be recorded, for instance, on the refer-
ence card accompanying the relay.
For secondary testing the relay must be dis-
connected from the voltage transformer circuits
and other secondary circuits by means of
disconnectable terminal blocks or a test adapter
fitted on the relay. A possible connection of the
relay to the circuit breaker trip coil must be
noted during the test.
When the auxiliary voltage is connected to the
relay, a self-testing program is carried out auto-
matically. The self-testing program includes the
whole relay except for the matching transform-
ers and the contacts of the output relays. The
operational condition of the relay is tested using
ordinary relay test equipment. The secondary
injection test also includes the matching trans-
formers, the output relays and the accuracy of
the operate values.
When no relay test set is available the secondary
injection test can be carried out with the follow-
ing equipment:
- regulating transformer
- isolating transformer, e.g. 220 V/220 V
- voltmeter
- stop watch or counter for time measurement
- dc voltage source
- switches and indicator lamps
- supply and pilot wires
- calibrated multimeter
Note the relay's rated voltage when measuring
wires are connected to the terminals of the relay,
see chapter Technical data, passage Energizing
inputs.
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