Def Aided Schemes - GE MiCOM P40 Agile Technical Manual

P543i/P545i
14

DEF AIDED SCHEMES

14.1 DEPENDENCY CONDITIONS
Some protection elements can be set to have dependencies on the availability of the protection communication
channel(s) and on the status of the voltage transformer supervision function (VTS).
If you are testing a distance model, the distance protection can be permanently enabled, or it can be set so that it
is only enabled in the event of a failure of the protection communications channel(s).
The overcurrent and earth faults elements can be permanently enabled, or can be set so that they are only
enabled:
in the event of a failure of the protection communications channel(s)
●
● in the event of a VTS alarm
according to a logical combination of both conditions.
●
If these elements are enabled with a dependency upon the above conditions, it is necessary to simulate the
condition to test the correct operation of the protection function.
A communications failure can be simulated by setting the Test Loopback cell to Disabled and checking that the IED
raises a Comms Fail alarm.
At the end of the test, clear the communications alarms and reset the statistics.
A VTS alarm can be raised by applying a 3-phase voltage to the VT inputs and then removing one phase voltage
for a duration exceeding the VTS Time Delay setting.
At the end of the tests, clear the VTS alarm.
14.2 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. Disable the current differential function, directly or indirectly:
a. If the distance element is enabled without dependency, disable the current differential element
Current Diff.
b. If the distance protection is enabled with dependency on communication channel failure, the current
differential element Current Diff should remain enabled and the communication should be disrupted
to cause a suitable failure of the current differential protection
4. Make a note of which elements need to be re-enabled after testing
We assume a conventional signalling scheme implementation.
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If an InterMiCOM 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.
P54x1i-TM-EN-1
Chapter 25 - Commissioning Instructions
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