1. Apply the fault condition, including initiation of CCRBRF (50BF), with phase
current well above set value Pickup_PH.
2. Interrupt the current, with a margin before back-up trip time, t2. It may be made
at issue of re-trip command.
3. Check that re-trip is achieved, if selected, but no back-up trip is obtained.
4. Disconnect AC and BFI_3P input signals.
The normal mode BuTripMode = 1 out of 3 should have been verified in the tests
above. In applicable cases the modes 1 out of 4 and 2 out of 4 can be checked. Choose
the mode below, which corresponds to the actual case.
Checking the case
BuTripMode
=
1 out of 4
M12104-165 v6
It is assumed that the ground-fault current setting Pickup_N is below phase current
setting Pickup_PH.
1. Set BuTripMode = 1 out of 4.
2. Apply the fault condition, including initiation of CCRBRF (50BF), with one-
phase current below set Pickup_PH but above Pickup_N . The residual ground-
fault should then be above set Pickup_N.
3. Verify that back-up trip is achieved after set time. If selected, re-trip should also
appear.
4. Disconnect AC and BFI_3P input signals.
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.
Section 13 1MRK 502 073-UUS A
Testing functionality by secondary injection
204 Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Commissioning manual
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