1. Apply the fault condition, including START of CCRBRF, with a current just
below set IN>.
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.
11.5.7.3 Checking the re-trip and back-up times
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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 = CB Pos Check .
1. Apply the fault condition, including start of CCRBRF, well above the set
current value. Measure the 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.
11.5.7.4 Verifying the re-trip mode
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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
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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.
Checking the re-trip with current check,
RetripMode
=
CB Pos Check
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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 are obtained.
Checking re-trip without current check
M12104-58 v9
Section 11 1MRK 505 378-UEN A
Testing functionality by secondary injection
184 Line differential protection RED670 2.2 IEC
Commissioning manual
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