1. Set RetripMode = Off.
2. Apply the fault condition, including initiation of CCRBRF (50BF), 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 BFI_3P input signals.
Checking the re-trip with current check, RetripMode = UseFunctionMode
M12104-48 v8
1. Set RetripMode = UseFunctionMode.
2. Apply the fault condition, including initiation of CCRBRF (50BF), 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 initiation of CCRBRF (50BF), with current below set current
value.
5. Verify that no re-trip, and no back-up trip is obtained.
6. Disconnect AC and BFI_3P input signals.
Checking re-trip without current check
M12104-58 v10
1. Set RetripMode = Always.
2. Apply the fault condition, including initiation of CCRBRF (50BF), 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 initiation of CCRBRF (50BF), with current below set current
value.
5. Verify that re-trip is achieved after set time t1, but no back-up trip is obtained.
6. Disconnect AC and BFI_3P input signals.
11.5.9.6 Verifying the back-up trip mode
M12104-146 v5
In the cases below it is assumed that FunctionMode = Current is selected.
Checking that back-up tripping is not achieved at normal CB tripping
M12104-150 v8
Use the actual tripping modes. The case below applies to re-trip with current check.
1. Apply the fault condition, including initiation of CCRBRF (50BF), with phase current well above set
value Pickup_PH.
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.
4. Disconnect AC and BFI_3P input signals.
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
M12104-165 v6
It is assumed that the ground-fault current setting Pickup_N is below phase current setting Pickup_PH.
1. Set BuTripMode = 1 out of 4.
2. Apply the fault condition, including initiation of CCRBRF (50BF), with one-phase current below set
Pickup_PH but above Pickup_N . The residual ground-fault should then be above set Pickup_N.
3. Verify that back-up trip is achieved after set time. If selected, re-trip should also appear.
4. Disconnect AC and BFI_3P input signals.
Section 11 1MRK 504 165-UUS Rev. J
Testing functionality by secondary injection
182 Transformer protection RET670
Commissioning manual
© 2017 - 2021 Hitachi Power Grids. All rights reserved
To Next Page
Loading...
