Page 292 - Offshore Electrical Engineering Manual
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CHAPTER
1
Installation Practice
SWITCHGEAR AND MOTOR CONTROL CENTRES
Although the majority of the installation work is usually done by the offshore con-
tractor, a technical representative from the switchgear manufacturer should be pres-
ent to ensure that the work is done to the manufacturer’s satisfaction and that any
problems can be rectified quickly.
The installers should be completely familiar with the equipment and all the
information regarding its installation. They should certainly not see it for the first
time as it is removed from the packing case at the installation site. This is par-
ticularly important with regard to foundation and supporting steelwork arrange-
ments. These must be in place, and of the correct dimensions, before installation
of the equipment itself can be attempted. Once the framework is in place, correctly
aligned, levelled and rigidly fixed, switchgear and control gear cubicles can be
bolted together in the required order as shown in the design drawings provided.
Identification labels should be checked to ensure that they correspond to the equip-
ment and the associated drawings. All the copper connections for busbars and ris-
ers should then be made using torque limiting tools, under the supervision of the
manufacturer’s representative. Where the manufacturer recommends or provides
special tools, only these should be used. ‘Ductor’ resistance testing of busbars
can then be carried out. Any busducting between the switchgear and associated
transformers or generators should be installed at this time, if this is possible. This
should avoid any stressing of connections. If the switchgear is being installed in
a module at a fabricator’s yard before being shipped offshore in the module, then
any transit packing removed should be retained, as this will be needed for repack-
ing to prevent any shock or movement damage during the shipment offshore. All
transit packing should be removed, and the equipment should be properly cleaned
before testing.
A check for correct mechanical operation will then need to be made.
This should prove that
1. withdrawable trucks, cubicles and interlocking devices function correctly;
2. circuit breaker mechanisms, isolators, switches and relays are free to open and
close properly.
By this time, the tripping battery and charger should have been installed and
commissioned. Nevertheless, it is worth checking that the tripping batteries are fully
charged before going any further.
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