Alstom MiCOM P546 - 5.1.3 Insulation; 5.1.4 External wiring; 5.1.5 Watchdog contacts

P54x/EN CM/La4 Commissioning
(CM) 10-18 MiCOM P543, P544, P545 & P546
CM
5.1.3 Insulation
Insulation resistance tests are only necessary during commissioning if it is required for them
to be done and they have not been performed during installation.
Isolate all wiring from the earth and test the insulation with an electronic or brushless
insulation tester at a dc voltage not exceeding 500 V. Terminals of the same circuits should
be temporarily connected together.
The main groups of relay terminals are:
 Voltage transformer circuits
 Current transformer circuits
 Auxiliary voltage supply
 Field voltage output and opto-isolated control inputs
 Relay contacts
 EIA(RS)485 communication port
 Case earth
The insulation resistance should be greater than 100 M at 500 V.
On completion of the insulation resistance tests, ensure all external wiring is correctly
reconnected to the relay.
5.1.4 External wiring
Chec
k 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
Usi
ng a continuity tester, check that the watchdog contacts are in the states given in the
table below for a de-energized relay.
Contact state
Terminals
Relay de-energized Relay energized
J11 - J12 (P543 & P544) Closed Open
J13 - J14 (P543 & P544) Open Closed
M11 - M12 (P545 & P546) Closed Open
M13 - M14 (P545 & P546) Open Closed
Table 2: Watchdog contact status