Checking the case with fault current below set value
Pickup_BlkCont
It simulates a case where the fault current is very low and operation will depend on CB
position signal from CB auxiliary contact. It is suggested that re-trip without current check
is used, setting RetripMode = No CBPos Check.
1. Set FunctionMode = Current/Contact.
2. Apply input signal for CB closed to relevant input or inputs 52a_A (B or C)
3. Apply the fault condition with input signal(s) for initiation of CCRBRF (50BF). The
value of current should be below the set value Pickup_BlkCont
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 AC and the BFI_3P signal(s). Keep the CB closed signal(s).
6. Apply the fault and the initiation again. The value of current should be below the set
value Pickup_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”.
9. Disconnect injected AC and BFI_3P input signals.
11.5.8.9 Completing the test
Continue to test another function or end the test by changing the TESTMODE setting to
Disabled. Restore connections and settings to their original values, if they were changed
for testing purposes.
11.5.9 Pole discrepancy protection CCPDSC (52PD)
Prepare the IED for verification of settings outlined in Section
"Preparing the IED to
verify settings".
11.5.9.1 Verifying the settings
1. External detection logic, Contact function selection = ContactSel setting equals
CCPDSC (52PD) signal from CB. Activate the EXTPDIND binary input, and
measure the operating time of CCPDSC (52PD).
Use the TRIP signal from the configured binary output to stop the timer.
2. Compare the measured time with the set value tTrip.
3. Reset the EXTPDIND input.
4. Activate the BLKDBYAR binary input.
This test should be performed together with Autorecloser SMBRREC (79).
5. Activate the EXTPDIND binary input.
Section 11 1MRK 504 165-UUS -
Testing functionality by secondary injection
196 Transformer protection RET670 2.2 ANSI
Commissioning manual
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