CM
Check that the CU issued a trip command to both bus-sections (PU1, PU2 PU4 and PU5
should have operated).
Important: The time indicated on the CU LCD is the duration of the operation of the CU trip
order + 250ms (time of the PU to CU minimum duration signal information).
The time indicated on a PU LCD is the duration of the operation of this PU backtrip
command with 200ms drop off.
The backtrip order is equal to (the maximum between the fault clearance time and 250 ms) –
tBF2 pick-up time.
For example, if tBF2 = 150ms and the fault is cleared before 400ms, the displayed value
will be 400ms.
For example, if tBF2 = 150ms and the fault is cleared in 500ms, the displayed value will be
500ms.
6.4 Check Application Settings
The settings applied should be carefully checked against the required application-specific
settings to ensure that they are correct, and have not been mistakenly altered during the
injection test.
There are two methods of checking the settings:
− Extract the settings from the relay using a portable PC running the appropriate
software via the front EIA(RS)232 port, located under the bottom access cover.
Compare the settings transferred from the relay with the original written application-
specific setting record. (For cases where the customer has only provided a printed
copy of the required settings but a portable PC is available).
− Step through the settings using the relay’s operator interface and compare them with
the original application-specific setting record.
Unless previously agreed to the contrary, the application-specific programmable scheme
logic will not be checked as part of the commissioning tests.
Due to the versatility and possible complexity of the programmable scheme logic, it is
beyond the scope of these commissioning instructions to detail suitable test procedures.
Therefore, when programmable scheme logic tests must be performed, written tests which
will satisfactorily demonstrate the correct operation of the application-specific scheme logic
should be devised by the Engineer who created it. These should be provided to the
Commissioning Engineer together with the digital medium containing the programmable
scheme logic setting file.
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