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>. It can be obtained by
applying a single-phase current.
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
0
) will be above set value IN>.
5. Verify that back-up trip is not achieved.
6. Disconnect AC and START input signals.
13.6.7.6 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.
1. Repeat the check of back-up trip time. Disconnect current and START input
signals.
2. Activate the input CBFLT. The output CBALARM (CB faulty alarm) should
appear after set time tCBAlarm. Keep the input activated.
3. Apply the fault condition, including start of CCRBRF, with current above set
current value.
4. Verify that back-up trip is obtained without intentional delay, for example
within 20ms from application of start.
5. Disconnect injected AC and STARTinput signals.
13.6.7.7 Verifying the case
RetripMode
=
Contact
It is assumed that re-trip without current check is selected, RetripMode = Contact.
1MRK 504 088-UEN C Section 13
Verifying settings by secondary injection
149
Installation and commissioning manual
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