Commissioning P54x/EN CM/La4
MiCOM P543, P544, P545 & P546
CM) 10-19
CM
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 the table below.
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 - 48 V [-] 19 to 65 V -
48 - 110 V [40 - 100 V] 37 to 150 V 32 - 110 V
110 - 250 V [100 - 240 V] 87 to 300 V 80 to 265 V
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 follo
wing group of tests verifies 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. The InterMiCOM
64
communication channel (where fitted)
should be disconnected to prevent the remote end relay being affected during the tests.
5.2.1 Watchdog contacts
Usi
ng a continuity tester, check the watchdog contacts are in the states given in Table 2 for
an energized relay.
5.2.2 LCD front panel display
The liqui
d crystal display is designed to operate in a wide range of substation ambient
temperatures. For this purpose, the Px40 relays have an “LCD Contrast” setting. This
allows the user to adjust how light or dark the characters displayed will be. The contrast is
factory pre-set to account for a standard room temperature, however it may be necessary to
adjust the contrast to give the best in-service display. To change the contrast, cell [09FF:
LCD Contrast] at the bottom of the CONFIGURATION column can be incremented (darker)
or de-cremented (lighter), as required.
Care
: Before applying a contrast setting, ensure that it will not render the display too light or
dark such that menu text becomes unreadable. Should such a mistake be made, it is
possible to restore a visible display by downloading a MiCOM S1 Studio setting file,
with the LCD Contrast set within the typical range of 7 - 11.
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