Troubleshooting P54x/EN TS/La4
MiCOM P543, P544, P545 & P546
(TS) 12-7
TS
7. MAL-OPERATION OF THE RELAY DURING TESTING
7.1 Failure of output contacts
An apparent failure of the relay output contacts may be caused by the relay configuration;
the following tests should be performed to identify the real cause of the failure. Note that the
relay self-tests verify that the coil of the contact has been energized, an error will be
displayed if there is a fault in the output relay board.
Test Check Action
1
Is the Out of Service LED
illuminated?
Illumination of this LED may indicate that the
relay is in test mode or that the protection
has been disabled due to a hardware verify
error (see Table 4).
2
Examine the Contact status in the
Commissioning section of the
menu.
If the relevant bits of the contact status are
operated then proceed to test 4, if not
proceed to test 3.
3
Verify by examination of the fault
record or by using the test port
whether the protection element is
operating correctly.
If the protection element does not operate
verify whether the test is being correctly
applied.
If the protection element does operate then it
will be necessary to check the programmable
logic, to ensure that the mapping of the
protection element to the contacts is correct.
4
Using the Commissioning/Test
mode function apply a test pattern
to the relevant relay output
contacts and verify whether they
operate (note the correct external
connection diagram should be
consulted). A continuity tester can
be used at the rear of the relay for
this purpose.
If the output relay does operate then the
problem must be in the external wiring to the
relay. If the output relay does not operate
this could indicate a failure of the output
relay contacts (note that the self-tests verify
that the relay coil is being energized).
Ensure that the closed resistance is not too
high for the continuity tester to detect.
Table 5: Failure of output contacts
7.1.1 High break outputs
Whe
n optional high-break outputs have been supplied, they will normally bring a small
improvement in operate time as well as the ability to break high currents. It should be noted,
however, that high-break outputs are polarity sensitive. External wiring must respect the
polarity shown on the external connection diagram for correct operation. If a problem is
suspected with the operation of these contacts, the polarity should be checked in the first
instance.
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