ABB BUE 사용자 설명서 - 페이지 6
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ABB BUE에 대해서도 마찬가지입니다: 유지 관리 매뉴얼 (20 페이지)
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Inspection
CAUTION
Approval should be given by the site engineer in
charge for inspection as well as for operating the tap-
changer.
It is recommended to inspect the tap-changer once a year.
This principally concerns the motor-drive mechanism and
refers to a visual inspection inside the BUE/BUL cabinet to
check that nothing is loose, and that the heater is functioning.
In the motor-drive mechanism a counter registers every tap-
change operation. During inspection the counter is read and
noted. If possible, motor and counter are to be tested by
operating one step and then back.
If the tap-changer has its own oil conservator, the breather
and the oil level indicator on the oil conservator are to be
checked according to the instructions from the transformer
manufacturer.
The inspection is to be carried out while the transformer is in
service.
On the conservator the following are to be checked:
– Oil level
– Breather
In the motor-drive mechanism the following items are to be
checked:
– Motor and counter
– Emergency stop
– Heater
– Earth fault protector for the outlet (option)
If the tap-changer is equipped with an oil filter unit, the
pressure drop over the filter is to be checked.
Required tools
The following eq uipment is required for the inspection:
– Set of screwdrivers
– Pen and note pad
6 User's manual UBB | 1ZSE 5492-156 en, Rev. 4
Procedure
WARNING
Checking of the breather and the oil level must be
carried out from ground level since the transformer is
energized.
1. Checking of the breather
WARNING
The breathers and the tube from the conservator
might contain explosive gases. No open fire, hot
surfaces or sparks may be present when removing the
breather.
Check the breather according to the instructions for the
transformer.
If more than half of the drying agent has changed colour, it
must be dried or replaced.
The drying agent usually starts to change colour from the
bottom of the breather. If it changes colour at the top of
the breather, there is a leakage in the connections to the
conservator. Locate the leakage and seal it.
2. Checking of the oil level in the conservator
The oil level in the conservator should be according to the
instructions in the transformer documentation.
3. Checking of the motor and the counter
Open the motor-drive cabinet door and turn the selector-
switch to the LOCAL position. Then turn the control switch to
the RAISE (LOWER) position.
Check that the motor works properly, the position indicator
increases (decreases) one step, and the counter advances
one step for each operation. Record the counter's value. The
counter shows the number of operations run by the tap-
changer (the overhaul schedule can be determined with the
help of this information).
Turn the control switch to the LOWER (RAISE) position.
Check that the motor also works properly in that direction,
the position indicator decreases (increases) one step and the
counter advances one step more.
Reset the draghands.