10.4.3 On-load Checks
The objectives of the on-load checks are:
• Confirm the external wiring to the current and voltage inputs is correct.
• Measure the magnitude of on-load current and voltage (if applicable).
• Check the polarity of each current transformer.
However, these checks can only be carried out if there are no restrictions preventing the
tenderization of the plant being protected.
Remove all test leads, temporary shorting leads, etc. and replace any external wiring that has
been removed to allow testing.
If it has been necessary to disconnect any of the external wiring from the protection in order to
perform any of the foregoing tests, it should be ensured that all connections are replaced in
accordance with the relevant external connection or scheme diagram. Confirm current and voltage
transformer wiring.
10.4.3.1 Final Checks
After the above tests are completed, remove all test or temporary shorting leads, etc. If it has been
necessary to disconnect any of the external wiring from the protection in order to perform the
wiring verification tests, it should be ensured that all connections are replaced in accordance with
the relevant external connection or scheme diagram.
Ensure that the protection has been restored to service.
If the protection is in a new installation or the circuit breaker has just been maintained, the circuit
breaker maintenance and current counters should be zero. If a test block is installed, remove the
test plug and replace the cover so that the protection is put into service.
Ensure that all event records, fault records, disturbance records and alarms have been cleared
and LED’s has been reset before leaving the protection.
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