P54x/EN CM/La4 Commissioning
(CM) 10-52
MiCOM P543, P544, P545 & P546
CM
8.4.9.2 OST setting
Clear all alarms. Set Tost to zero. Based on healthy voltages (VA = VB = VC = 57.8 V)
calculate the currents to generate the impedances as per Table 12.
State 1 State 2 State 3 State 4
Apply IA = IB = IC =
61.1
8.57
R
)56(
2
1
5
8.57
RRR
59.0
8.57
R
'51.1
8.57
R
Angle 0° 0° 0° 180°
Duration 500 ms
Longer than
‘Delta t’ set time
100 ms 500 ms
Table 12: OST state sequence
Note: Angle in the table above is the angle between voltages and their
respective currents. Also note that in state 4 the currents are
displaced 180° from their respective voltages.
Now apply the 4 state sequence to the relay under test and observe that the relay has
tripped 3 phase and that an associated ‘OST’ alarm is displayed on the local LCD.
8.4.9.3 Predictive and OST setting
As per ‘Predi
ctive OST’ above.
8.4.9.4 ‘Tost’ timer test
Rep
eat the test as for ‘Predictive OST’ and observe that the 3phase tripping will come up
after ‘Tost’ set time delay. Record the operating time in the commissioning record sheet.
8.4.10 Directional earth fault aided scheme (ground current pilot scheme)
If the Aided DEF protecti
on function is being used, it should be tested. If not, skip to section
8.4.12.
Refer to section 8.4.1, check for any possible dependen
cy conditions and simulate as
appropriate.
To avoid spurious operation of any phase diff, distance, overcurrent, earth fault or breaker
fail elements, these should be disabled for the duration of the DEF tests. This is done in the
relay’s CONFIGURATION column. If the earth fault element is enabled without qualification
of communication channel failure, then the current differential element [090F: Phase Diff],
should be disabled. If the earth fault protection is enabled on communication channel failure,
then the differential element should remain enabled and the communication should be
disrupted to cause a suitable failure of the phase differential protection. Make a note of
which elements need to be re-enabled after testing.
Testing of the P54x DEF scheme is detailed in the case of conventional signaling scheme
implementation as it is expected that the signaling will be independent to that of the
communication for the phase differential protection. In the case where an InterMiCOM
64
scheme is being employed to provide the signaling, it may be that the scheme logic does not
use opto-inputs for the aided scheme implementation and that internal logic signals (DDBs)
will need to be set/reset in order to test the operation of the protection scheme. The IM64
Test Mode in conjunction with the IM64 Test Pattern should be used to assert/monitor the
relevant signals.
This set of injection tests aims to determine that a single P54x relay, at one end of the
scheme is performing correctly. The relay is tested in isolation, with the communications
channel to the remote line terminal disconnected. Verify that the P54x relay cannot send or
receive channel scheme signals to/from the remote line end.
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