GE PHI 530.1425.2500 Operating And Maintenance Instructions Manual page 20

The valve blocks can be of two types, the type named Filtering valve block, that includes three different valves
(see Figure 10 a) and the type named By-pass valve block, that includes the by-pass valve only (see Figure 10
b).
Filter valve
Filter valve
a) Filtering valves block
Vacuum pump and oil filling and filtering equipment can be connected to the filtering valves through two ¾" BSP
connections placed on the side of each filter valve block. These connections are protected by a removable cap
(see Figure 11).
By-pass valves are placed in both type of blocks and are necessary to ensure the proper oil circulation during
the normal bushing operation. The by-pass valve blocks are not equipped with the ¾" BSP connections.
Next Table 11 describes the correct valve positions as a function of the specific operative conditions on the
bushing.
Operative condition
Oil filling and filtering
Bushing normal operation
HVDC TRANSFORMER BUSHINGS
PHI 530.1425.2500
To the pump
y-pass valve
B
To the pump
Figure 10 – PHI bushing valves
Filtering valves
Table 11 – Filtering and by-pass valve position
PHI 265.850.1500
Kepco project
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IS 2664 GB
Page 20 of 70
By-pass
valve
b) By-pass valve block
By-pass valves
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