CSS sahara_02_04_instructions.doc
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All units have taps located in the High Voltage winding. The tap arrangement is shown on the nameplate
of the transformer. These taps are provided to furnish rated output voltage when the input voltage differs
from the rated voltage.
To change tap connections, do the following steps:
1. De-energized the unit, short-circuit both the high and low voltage connections and ground both
sides.
2. Unlock the tap changer handle, and then move the taps changer handle to the desired tap, then
locked the tap changer handle.
3. Remove safety shorts and ground connections from the high voltage and low voltage buses.
After ensuring that no tools or hardware was left in the enclosure, and the enclosures are closed properly,
you may then re-energize the Package Compact Substation. Make sure that the tap connections are proper
for the required voltage as listed on the nameplate. The transformer is normally shipped with the tap
changer for the rated voltage.
Cable Connections
When making outside cable connections, conductors suitable for at least 85°C should be used. All
connections should be made without placing undue stress on the terminals.
Conductors should be securely fastened in place and adequately supported with allowances for expansion
and contraction.
FINAL INSPECTION PRIOR TO ENERGIZATION
After the Package Compact Substation has been found to be in good condition and the protective
equipment is operational, the substation may be connected to the network. However, it is recommended
that the transformer to be left to settle for 1 or 2 days after installation so those air bubbles in the oil have
time to dissolve before connecting the voltage.
Before energizing the unit, a complete electrical inspection should be made. The following checklist
should be used as a minimum requirement.
Electrical Inspection
[ ]
All external connections have been made properly (phasing of connections to terminals, etc.).
[ ]
All connections are tight and secure.
[ ]
All accessory circuits are operational. Check the transformer protective equipment and test the
function of their electrical circuits:
•
Thermometers (alarms, tripping)
•
Pressure relay (tripping)
•
Oil level indicator
•
Ensure that all fuses are inserted and in the correct position
[ ]
All tap connections are properly positioned.
[ ]
The neutral and ground connections have been properly made.
Mechanical Inspection
WARNING WARNING WARNING WARNING WARNING WARNING
TAP CONNECTIONS MAY BE CHANGED ONLY WHEN THE UNIT IS
TOTALLY DE-ENERGIZED.
