7 Checking before Power-On and Power- Off
System Manual
42
No.
Checking item
10
Check the external air insulation distance. Whether the air insulation distance
between different voltage grade bushing and bushing to ground conforms to
relevant standard.
11
The oil leak port of the transformer room is not blocked.
12
The screen door of the transformer room is closed and locked.
Remove the Locking Device
Fig. 7-1
Remove the locking device of the pressure relief valve
Adjust Voltage Ratio via Tap Changer
Tap changer can adjust transformer output voltage. When operating tap changer, ensure
that transformer is in the no-excitation state, that is, the high and low voltage sides of
transformer are not live. When voltage of the low-voltage side remains unchanged, the
output voltage on high-voltage side at different taps are:
Tap position
Value
1
Nominal Value x 1.05
2
Nominal Value x 1.025
3
Nominal Value
4
Nominal Value x 0.975
5
Nominal Value x 0.95
Take tap position 1 as an example, the steps to adjust the voltage ratio is shown in the
following figure.
