Operation & Maintenance Manual
17
COMMISSIONING
This section is a guide to the minimum checks and tests that
should be performed on site prior to energising the equipment.
6.1 - PRELIMINARY CHECKS
Preliminary inspections should be carried out prior to the
connection of the high voltage supply:
1) Check the mechanical and electrical interlocks for correct
operation.
2) Check that the switchboard is earthed to the station
earthing.
3) Check the gas monitors for correct operating pressure
within the green zone.
4) Check that the control power is on.
5) Conduct a primary current injection on the protection relay
to ensure functional operation with proper test set.
6) Perform a dielectric test on the power cables to appropriate
standards.
7) Conduct an operational test on the panel's control and
protection system.
8) Check the general condition of the switchboard for any
abnormalities that will affect operations.
9) Check external equipment such as remote controls, auxiliary
power source and substation condition.
6.2 - TESTING
On site test for the gas- lled compartments should include the
following:
a) Hipot test of the main circuits. (PT should be isolated from
the main circuit before test)
b) Moisture content of gas one day after gas lling.
c) Contact resistance & Insulation resistance
d) Current Injection on Primary & Secondary Circuit
6.3 - START-UP
1) During start-up, safety regulations should be observed.
2) Ensure that all the switch-disconnectors and circuit breakers
are in off position.
3) Remove any connecting or shorting links used during the
preliminary tests.
4) Energise the switchboard step-by-step, observing all signals
and indicators.
5) Watch for any abnormalities.
6.4 - SWITCHING OPERATIONS
6.4.1 - POSITION ISOLATION
The 3-position disconnecting switch selects one of three
positions-ON, OFF and Earth by a pair of blades.
The cable side may be earthed through the circuit breaker. It can
be electrically and mechanically interlocked with an associated
circuit breaker. For details, refer to the relevant instruction
manual.
Manual operation: Please refer to the attached manual (and the
caution plate on the operating device). for the operation of the
Disconnecting Switch.
Electrical operation: As a precaution for electrical operation, the
manual operation handle must be OUT. After the interlock is
cancelled, turn the handle of the Disconnect or control switch on
the front door panel. Only one disconnecting switch can be
operated at any one time.
This section is a guide to the minimum checks and tests that
should be performed on site prior to energising the equipment.
6.4.2 - Interlocks between VCB and 3-Position
Disconnecting Switch.
The disconnecting switch cannot interrupt load current. Hence,
the switch can only be operated when the breaker is OFF.
When the breaker is ON, the mechanical and electrical interlocks
prevent the disconnecting switch from being operated.
In addition, closure of breaker is not possible when the
disconnecting switch operation is in progress. Operation of the
switches or breaker is not possible with the shutter of the switch
opened.
PRECAUTION:
The interlock system may differ from case to
case. Refer to the operating system in the schematic drawings.
6.4.3 - Circuit Breaker Operation
Manual operation: Refer to the Breaker Installation Manual and
the caution plate of the operating device for the operation of the
breaker.
Electrical operation:
Turn the local breaker control switch (TNC)
6.0 COMMISSIONING
