Forward Fault Trip Test; Scheme Testing; Signal Send Test For Permissive Schemes; Signal Send Test For Blocking Schemes - GE MiCOM P40 Technical Manual

P446SV
12.1.3

FORWARD FAULT TRIP TEST

A forward fault is now injected as described, with the intention to cause a scheme trip.
For a permissive scheme, the Signal Receive opto-input should be energised. This is done by applying a
continuous DC voltage onto the required opto-input, either from the test set, station battery, or IED field voltage.
The commissioning engineer decides on the best method.
For a blocking scheme, the opto-input should remain de-energised ("OFF").
1. Apply the fault and record the (phase A) trip time.
2. Switch OFF the AC supply and reset the alarms.
The aided earth fault (DEF) scheme trip time for POR schemes (permissive overreach) 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.
12.2

SCHEME TESTING

12.2.1

SIGNAL SEND TEST FOR PERMISSIVE SCHEMES

1. Reconnect the test set so that the timer is no longer stopped by the Trip contact, but is now stopped by the
Signal Send contact (the contact that would normally be connected to the pilot/signalling channel).
2. Repeat the forward fault injection, and record the Signal Send contact operating time. The measured
operating time should typically be less than 40 ms.
3. Switch OFF the AC supply and reset the alarms.
12.2.2

SIGNAL SEND TEST FOR BLOCKING SCHEMES

1. Reconnect the test set so that the timer is no longer stopped by the Trip contact, but is now stopped by the
Signal Send contact. This is the contact that would normally be connected to the pilot/signalling channel.
2. Reverse the current flow direction on the A phase to simulate a reverse fault.
3. Perform the reverse fault injection and record the signal send contact operating time. The measured
operating time should typically be less than 40 ms.
4. Switch OFF the AC supply and reset the alarms.
Caution:
When the tests are completed, restore all settings that were disabled for testing
purposes.
Caution:
Remove any wires or leads temporarily fitted to energise the channel receive opto-
input.
P446SV-TM-EN-1
Chapter 24 - Commissioning Instructions
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