Checking the case BuTripMode = 2 out of 4
M12104-179 v7
The ground-fault current setting Pickup_N may be equal to or below phase-current setting Pickup_PH.
1. Set BuTripMode = 2 out of 4.
2. Apply the fault condition, including initiation of CCRBRF (50BF), with one-phase current above set
Pickup_PH and residual (ground fault) above set Pickup_N.
3. Verify that back-up trip is achieved after set time. If selected, re-trip should also appear.
4. Apply the fault condition, including initiation of CCRBRF (50BF), with at least one-phase current
below set Pickup_PH and residual (ground fault) above set Pickup_N. The current may be
arranged by feeding three- (or two-) phase currents with equal phase angle (I0-component) below
Pickup_PH, but of such value that the residual (ground fault) current (3I
0
) will be above set value
Pickup_N.
5. Verify that back-up trip is not achieved.
6. Disconnect AC and BFI_3P input signals.
11.5.9.7 Verifying instantaneous back-up trip at CB faulty condition
M12104-197 v7
Applies in a case where a signal from CB supervision function regarding CB being faulty and unable to
trip is connected to input 52FAIL.
1. Repeat the check of back-up trip time. Disconnect current and input signals.
2. Activate the input 52FAIL. The output CBALARM (CB faulty alarm) should appear after set time
tCBAlarm. Keep the input activated.
3. Apply the fault condition, including initiation of CCRBRF (50BF), with current above set current
value.
4. Verify that back-up trip is obtained without intentional delay, for example within 20ms from
application of initiation.
5. Disconnect injected AC and BFI_3P input signals.
11.5.9.8 Verifying the case FunctionMode = CB Pos
GUID-06D1545D-31F7-4B48-821E-151212962A81 v1
It is assumed that re-trip without current check is selected, RetripMode = UseFunctionMode.
1. Set FunctionMode = CB Pos.
2. Apply input signal for CB closed to relevant input or inputs 52A_A, 52A_B or 52A_C.
3. Apply the input signal, or signals for the start of CCRBRF.
4. Verify that phase selection re-trip and backup trip are achieved after set times.
5. Disconnect the start signal(s). Keep the CB closed signal(s).
6. Apply input signal(s), for start of CCRBRF.
7. Arrange disconnection of CB closed signal(s) well before set backup trip time t2
8. Verify that backup trip is not achieved.
11.5.9.9 Verifying the case RetripMode = Contact
M12104-213 v10
It is assumed that re-trip without current check is selected, RetripMode = Contact.
1. Set FunctionMode = Contact
2. Apply input signal for CB closed to relevant input or inputs 52a_A (B or C).
3. Apply input signal, or signals for initiation of CCRBRF (50BF).
4. Verify that phase selection re-trip and back-up trip are achieved after set times.
1MRK 504 165-UUS Rev. J Section 11
Testing functionality by secondary injection
Transformer protection RET670 183
Commissioning manual
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