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Section 11
Testing functionality by secondary injection
1.
Set RetripMode = Always.
2.
Apply the fault condition, including start of CCRBRF, well above the set current value.
3.
Verify that re-trip is achieved after the set time t1, and the back-up trip after time t2.
4.
Apply the fault condition, including start of CCRBRF, with current below set current value.
5.
Verify that re-trip is achieved after set time t1, but no back-up trip is obtained.
11.5.8.6
Verifying the back-up trip mode
In the cases below it is assumed that FunctionMode = Current is selected.
Checking that back-up tripping is not achieved at normal CB tripping
Use the actual tripping modes. The case below applies to re-trip with current check.
1.
Apply the fault condition, including start of CCRBRF, with phase current well above set value
IP>.
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.
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
It is assumed that the earth-fault current setting IN> is below phase current setting IP>.
1.
Set BuTripMode = 1 out of 4.
2.
Apply the fault condition, including start of CCRBRF, with one-phase current below set IP> but
above IN>. The residual earth-fault should then be above set IN>.
3.
Verify that back-up trip is achieved after set time. If selected, re-trip should also appear.
4.
Disconnect AC and START input signals.
Checking the case BuTripMode = 2 out of 4
The earth-fault current setting IN> may be equal to or below phase-current setting IP>.
1.
Set BuTripMode = 2 out of 4.
2.
Apply the fault condition, including start of CCRBRF, with one-phase current above set IP> and
residual (earth fault) above set IN>.
3.
Verify that back-up trip is achieved after set time. If selected, re-trip should also appear.
4.
Apply the fault condition, including start of CCRBRF, with at least one-phase current below set
IP> and residual (earth fault) above set IN>. The current may be arranged by feeding three- (or
two-) phase currents with equal phase angle (I0-component) below IP>, but of such value that
the residual (earth fault) current (3I
5.
Verify that back-up trip is not achieved.
6.
Disconnect AC and START input signals.
11.5.8.7
Verifying instantaneous back-up trip at CB faulty condition
Applies in a case where a signal from CB supervision function regarding CB being faulty and unable
to trip is connected to input CBFLT.
166
) will be above set value IN>.
0
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1MRK 505 378-UEN Rev. K
Line differential protection RED670
Commissioning manual
M12104-146 v5
M12104-150 v8
M12104-165 v6
M12104-179 v7
M12104-197 v7
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