4. Verify that phase selection re-trip (if selected) and back-up trip are achieved
after set times. Failure to trip is simulated by keeping the signal(s) CB closed
activated.
5. Disconnect the input signal and the ST
ART signal(s). Keep the CB closed
signal(s).
6. Apply the fault and the start again. The value of current should be below the
set value I>BlkCont.
7. Arrange disconnection of BC closed signal(s) well before set back-up trip
time t2. It simulates a correct CB tripping.
8. Verify that back-up trip is not achieved. Re-trip can appear for example, due
to selection “Re-trip without current check”.
11.5.7.8 Completing the test
M12104-72 v5
Continue to test another function or end the test by changing the TESTMODE
setting to Off. Restore connections and settings to their original values, if they were
changed for testing purposes.
11.5.8 Stub protection STBPTOC
M14922-2 v7
Prepare the IED for verification of settings outlined in Section
"Preparing the IED
to verify settings".
Logical signals for STBPTOC protection are available on the local HMI
under
Main menu/Settings/Setting group N/Current protection/Stub(PTOC,
50STB)/STBPTOC:x
11.5.8.1 Measuring the operate limit of set values
M14922-6 v8
1. Check that the input logical signals BLOCK and RELEASE and the output
logical signal TRIP are all logical zero.
2. Activate the input RELEASE on the STBPTOC function block
3. For a short while inject a current (fault current) in one phase to about 110% of
the set operating current, and switch the current off.
Observe to not exceed the maximum permitted overloading of the current
circuits in the IED.
4. Switch the fault current on and measure the operating time of STBPTOC.
Use the TRIP signal from the configured binary output to stop the timer. The
operation should be instantaneously.
5. Activate the input BLOCK on the STBPTOC function block.
6. Switch on the fault current (110% of the setting).
No TRIP signal should appear.
7. Switch off the fault current.
8. For a short while inject a current (fault current) in same phase to about 90%
of the set operating current, and switch the current off.
9. Switch the fault current on.
1MRK 505 378-UEN A Section 11
Testing functionality by secondary injection
Line differential protection RED670 2.2 IEC 187
Commissioning manual
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