1. Set RetripMode = CB Pos Check.
2. Apply the fault condition, including start of CCRBRF, well above the set current
value.
3. Verify that re-trip is achieved after set time t1 and back-up trip after time t2
4. Apply the fault condition, including the start of CCRBRF, with the current
below the set current value.
5. Verify that no re-trip, and no back-up trip is obtained.
Checking re-trip without current check
1. Set RetripMode = No CBPos Check.
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.
10.5.8.5 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.
1MRK 506 355-UEN A Section 10
Testing functionality by secondary injection
Line distance protection REL670 2.1 IEC 159
Commissioning manual
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