GE MiCOM P40

12 DEF AIDED SCHEMES
12.1 EARTH CURRENT PILOT SCHEME
1. Check for any possible dependency conditions and simulate as appropriate.
2. In the CONFIGURATION column, disable all protection elements other than the one being tested.
3. Make a note of which elements need to be re-enabled after testing.
We assume a conventional signalling scheme implementation.
If an InterMiCOM
64
scheme is used to provide the signalling, the scheme logic may not use opto-inputs for the
aided scheme implementation. In this case, internal logic signals (DDBs) need to be set or reset to test the
operation of the protection scheme.
The IM64 Test Mode in conjunction with the IM64 Test Pattern should be used to assert or monitor the relevant
signals.
This set of injection tests aims to determine that a single device, at one end of the scheme is performing correctly.
Note:
The device must be tested in isolation, with the communications channel to the remote line terminal disconnected.
12.1.1
PRELIMINARIES
1. Determine which output relays have been selected to operate when a DEF trip occurs, by viewing the
programmable scheme logic. If the trip outputs are phase segregated (a different output relay allocated for
each phase), the output relay assigned for tripping on ‘A’ phase faults should be used.
2. Connect the output relay so that its operation will trip the test set and stop the timer.
3. Connect the current output of the test set to the ‘A’ phase current transformer input
4. Connect, all three phase voltages Va, Vb, and Vc.
5. Depending on the test equipment used, make sure the timer is set to start when the current is applied.
12.1.2
PERFORM THE TEST
1. Ensure that the timer is reset and prepare the following test shot.
2. Simulate a forward fault on the A-phase. The A-phase voltage must be simulated to drop by 4 times the DEF
VNpol Set setting; Va = Vn - 4 (DEF Vpol)
3. Set the fault current on the A-phase should to 2 times the 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; Ia = 2
(IN DEF Threshold Ð q DEF)
4. Phases B and C should retain their healthy pref-ault voltage, and no current. The duration of the injection
should be in excess of the DEF Delay setting (typically Aid. 1 DEF Dly. and Aid. 2 DEF Dly. + 100 ms).
IED 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
Chapter 24 - Commissioning Instructions P446SV
644 P446SV-TM-EN-1