Alstom MiCOM P846, Technical Manual

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P846/EN CM/D Commissioning
(CM) 10-12
MiCOM P846
5.1.4 External wiring
Check that the external wiring is correct to the relevant relay diagram and scheme
diagram. Ensure as far as practical that phasing/phase rotation appears to be as
expected. The relay diagram number appears on the rating label under the top access
cover on the front of the relay.
If a P991 test block is provided, the connections should be checked against the scheme
(wiring) diagram. It is recommended that the supply connections are to the live side of the
test block colored orange with the odd numbered terminals (1, 3, 5, 7 etc.). The auxiliary
supply is normally routed via terminals 13 (supply positive) and 15 (supply negative), with
terminals 14 and 16 connected to the relay’s positive and negative auxiliary supply terminals
respectively. However, check the wiring against the schematic diagram for the installation to
ensure compliance with the customer’s normal practice.
5.1.5 Watchdog contacts
Using a continuity tester, check that the watchdog contacts are in the states given in Table 2
for a de-energized relay.
Contact State
Terminals
Relay De-energized Relay Energized
M11 – M12 (P846) Closed Open
M13 – M14 (P846) Open Closed
Table 2: Watchdog contact status
5.1.6 Auxiliary supply
The relay can be operated from either a dc only or AC/DC auxiliary supply depending on the
relay’s nominal supply rating. The incoming voltage must be within the operating range
specified in Table 3.
Without energizing the relay, measure the auxiliary supply to ensure it is within the operating
range.
Nominal Supply Rating DC [AC rms] DC Operating Range AC Operating Range
24 - 48V [-] 19 to 65V -
48 - 110V [30 - 100V] 37 to 150V 24 - 110V
125 - 250V [100 - 240V] 87 to 300V 80 to 265V
CM
Table 3: Operational range of auxiliary supply Vx
It should be noted that the relay can withstand an ac ripple of up to 12% of the upper rated
voltage on the dc auxiliary supply.
Do not energize the relay or interface unit using the battery charger with the battery
disconnected as this can irreparably damage the relay’s power supply circuitry.
Energize the relay only if the auxiliary supply is within the specified operating ranges. If a
test block is provided, it may be necessary to link across the front of the test plug to connect
the auxiliary supply to the relay.
5.2 With the relay energized
The following group of tests verify that the relay hardware and software is functioning
correctly and should be carried out with the auxiliary supply applied to the relay.
The current and voltage transformer connections must remain isolated from the relay for
these checks. The trip circuit should also remain isolated to prevent accidental operation of
the associated circuit breaker.