Commissioning P54x/EN CM/La4
MiCOM P543, P544, P545 & P546
CM) 10-53
CM
8.4.10.1 Connect the test circuit
Determine which output relay(s) has/have been selected to operate when a DEF trip occurs
by viewing the relay’s programmable scheme logic.
If the trip outputs are phase-segregated (i.e. a different output relay allocated for each
phase), the relay assigned for tripping on ‘A’ phase faults should be used.
Connect the output relay so that its operation will trip the test set and stop the timer.
Connect the current output of the test set to the ‘A’ phase current transformer input of the
relay. Connect, all three phase voltages to the relay Va, Vb, and Vc. Ensure that the timer
will start when the current is applied to the relay.
Ensure that the timer is reset, and prepare the test shot below:
Simulate a forward
fault on the A-phase. The A-phase voltage must be simulated to
drop by 4 times the [3905] or [3906] : “DEF Vpol” setting, i.e.:
Va = Vn - (4 x DEF Vpol)
The fault current on the A-phase should be set to 2 times the [3907: DEF Threshold] setting,
and in the forward direction. For a forward fault, the current Ia should lag the voltage Va by
the DEF Char Angle setting, i.e.:
Ia = 2 x IN
DEF Threshold
DEF
Phases B and C should retain their healthy prefault voltage, and no current. The duration of
the injection should be in excess of the DEF Delay setting (typically tDEF Delay + 100 ms).
RELAY RESPONSE
Direction of
fault test
injection
Forward fault Reverse fault
Signal
Receive Opto
ON OFF ON OFF
Blocking
Scheme
No Trip,
No Signal Send
Trip,
No Signal Send
No Trip,
Signal Send
No Trip,
Signal Send
Permissive
Scheme
(POR/POTT)
Trip,
Signal Send
No Trip,
Signal Send
No Trip,
No Signal Send
No Trip,
No Signal Send
A forward fault will be injected as described, with the intention to cause a scheme trip. As in
the table, for a Permissive scheme the Signal Receive opto input will need to be ON
(energized). This should be performed by applying a continuous DC voltage onto the
required opto input, either from the test set, station battery, or relay field voltage
(commissioning engineer to ascertain the best method).
For a blocking scheme, the opto should remain de-energized (“OFF”).
8.4.10.2 DEF aided scheme - forward fault trip test
Apply the fau
lt and record the (phase A) trip time. Switch OFF the ac supply and reset the
alarms.
The aided ground fault (DEF) scheme trip time for POR schemes should be less than 40 ms.
For blocking
schemes, where a non-zero DEF Dly time delay is set, the expected
operating time is typically within +/- 5% of the delay setting plus the “instantaneous”
(40 ms) delay quoted above.
There is no need to repeat the test for phases B and C, as these trip assignments have
already been proven by the distance/delta trip tests.
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