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.
12.5.9.6
Verifying instantaneous back-up trip at CB faulty condition
M12104-197 v6
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.
12.5.9.7
Verifying the case
RetripMode = Contact
M12104-213 v9
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 CBCLDL1, CBCLD2 or CBCDL3.
3.
Apply the input signal, or signals for the start of CCRBRF.
4.
Verify that phase selection re-trip and back-up 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.
8.
Arrange disconnection of CB closed signal(s) well before set back-up trip time
t2.
9.
Verify that back-up trip is not achieved.
12.5.9.8
Verifying the function mode
Current&Contact
M12104-237 v5
To be made only when
FunctionMode = Current&Contact is selected. It is suggested to make
the tests in one phase only, or at three-phase trip applications for just three-phase tripping.
Checking the case with fault current above set value
IP>
M12104-241 v6
The operation shall be as in
FunctionMode = Current.
1.
Set
FunctionMode = Current&Contact.
2.
Leave the inputs for CB close inactivated. These signals should not influence.
3.
Apply the fault condition, including the start of CCRBRF, with the current above the set
IP> value.
4.
Check that the re-trip, if selected, and back-up trip commands are achieved.
Checking the case with fault current below set value
I>BlkCont
M12104-281 v9
The case shall simulate a case where the fault current is very low and operation will depend on
CB position signal from CB auxiliary contact. It is suggested that re-trip without current check
is used, setting
RetripMode = No CBPos Check.
1MRK 502 067-UEN B
Section 12
Testing functionality by secondary injection
167
Commissioning manual
