Micom P721, Техническое руководство

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Commissioning and Maintenance P72x/EN CM/C21
MiCOM P721/P723 Page 23/28
measure the voltage across the P72x and the stabilizing resistor. The voltage reading
should be noted when the P72x operates, and this voltage should be very close to the Vs
(stability voltage). The sensitivity test should be performed for each discriminating zone and
for the overall check zone. The primary operating current should be very close to the
effective relay setting or primary operating current calculated. Figure 10 shows the
sensitivity test connections. During this test the P79x auxiliary relay should be kept
energized, thus the stabilizing resistor is not short circuited.
FIGURE 10: BUSBAR APPLICATION - PRIMARY INJECTION – SENSITIVITY TEST
4.9 Final checks
The tests are now complete. Remove all test or temporary shorting leads, etc.. If it is
necessary to disconnect any of the external wiring from the relay to perform the wiring
verification tests, ensure that all connections are replace in accordance with the relevant
external connection or scheme diagram.
If a MMLG test block is installed, remove the MMLB01 test plug and replace the MMLG
cover so that the protection is put into service.
Ensure that all event, fault and disturbance records, alarms and LEDs have been reset
before leaving the relay.