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Note! If
NoI>check
or
Retrip off
is set, only back-up trip can
be used to check set
IP>
.
13.6.7.2
Checking the residual (earth fault) current operate value
IN> set
below
IP>
Check the low set
IN>
current where setting
FunctionMode
=
Current
and setting
BuTripMode
=
1 out of 4
1.
Apply the fault condition, including START of CCRBRF, with a current just
below set
IN>Pickup_N
.
2.
Repeat the fault condition and increase the current in steps until trip appears.
3.
Compare the result with the set
IN>
.
4.
Disconnect AC and START input signals.
13.6.7.3
Checking the re-trip and back-up times
The check of the set times can be made in connection with the check of operate
values above.
Choose the applicable function and trip mode, such as
FunctionMode
=
Current
and
RetripMode
=
I> check
.
1.
Apply the fault condition, including start of CCRBRF, well above the set
current value. Measure time from START of CCRBRF.
2.
Check the re-trip
t1
and back-up trip times
t2
and
t3
.
In applicable cases, the back-up trip for multi-phase start
t2MPh
and back-up
trip 2,
t2
and
t3
can also be checked. To check
t2MPh
, a two-phase or three-
phase start shall be applied.
3.
Disconnect AC and START input signals.
13.6.7.4
Verifying the re-trip mode
Choose the mode below, which corresponds to the actual case.
In the cases below it is assumed that
FunctionMode
=
Current
is selected.
Checking the case without re-trip,
RetripMode = Retrip Off
1.
Set
RetripMode
=
Retrip Off
.
2.
Apply the fault condition, including start of CCRBRF, well above the set
current value.
3.
Verify that no re-trip, but back-up trip is achieved after set time.
4.
Disconnect AC and START input signals.
1MRK 504 088-UEN C
Section 13
Verifying settings by secondary injection
147
Installation and commissioning manual
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