Westinghouse PS-1002 Instruction Book page 4

2
CHECK LIST
External Inspection of Transformer
Blocking and Tie Chains
Are all tie-down chains undamaged?
1.
2. Is all blocking tight and in good
condition?
3. Is there any evidence of load shifting
in transit?
Transformer Tank and Fittings
4. Are there indications of external
damage?
5 . Is the paint finish damaged?
6. Are all fittings which are shipped
attached still in place and undamaged?
7. Is there any evidence of oil leakage?
(units shipped in oil)
8 . Is there either p ositive pressure or
vacuum in the tank? (in cold weather
a vacuum reading may be obtained)
Bushings ( when shipped attached)
9 . Are any porcelains chipped or other-
wise damaged?
1 0 . Is oil level in oil-fil l e d bushings
normal?
and for damage to m oisture barriers or waterproof wrap­
pings when use d.
The detail parts should be stored in an area that will
minimize exposure to weather and the possibility of dam­
age or loss. Refer to Section 4, "STORAGE PRIOR TO
ENERGIZING".
2.5 Internal Inspections
When a new transformer is delivered, an internal inspec­
tion is normally not required. Temporary shipping braces
are not used inside the transformer.
These conditions require an internal inspection:
- Transformer Tank Damage
- Broken Bushings
-·Inoperative Tap Changer or Switches
Before opening the transformer, the following precau­
tions should be taken:
a) Bleed off any internal pressure, to prevent the hand­
hole cover from blowing off when the bolts are removed.
Internal pressure may be relieved by use of gas sample
Answer
Indicates
valves; or by using a pressure relief valve when supplied.
Possible (or by SLOWLY removing the filling plug a thread at a
Damage
time until the pressure starts to relieve itself.)
No
The fdling plug can be blown off if the plug is removed
No
from a pressurized transformer too quickly. Personnel
Yes could be injured by the plug. Oil or oil vapor could be
expeUed creating a fire hazard.
b) Ventilate the gas space with dry air to purge it of the
Yes
nitrogen gas that it contains. Refer to Section 8.6.
Yes
No
TO AVOID DEATH FROM SUFFOCATION NEVER AL­
Yes
LOW ANYONE TO ENTER THE TRANSFORMER
TANK UNLESS AN ANALYSIS OF THE AIR IN THE
TANK SHOWS AT LEAST 1 9.5% OXYGEN. THE GAS
N o
SPACE OF AN OPERATING TRANSFORMER CON­
SISTS OF NITROGEN GAS. WHENEVER ANYONE IS
IN THE TANK, A PERSON SHOULD BE STATION ED
Yes
AT THE MANHOLE OUTSIDE THE TANK TO INSURE
SAFETY OF THE PERSON INSIDE.
No
c) Do not open the t ransformer in an area unprotected
from weather, during precipitation or in an area where the
air may contain dirt or other particles. Either of the above
could cause a transformer failure. If the transformer is
opened, the openings should at all times be protected
against entry of foreign matter into the transformer tank.
It may be necessary to remove some oil from oil-filled
units for adequate inspection. If this is done, refilling of
the transformer must be done as specified in Section 8.4.
The principle objective of the internal inspection is to
locate any damage which might h ave occurred in ship­
ment. Particular attention should be paid to leads, bolted
mechanical and electrical joints, tap changers, current
transformers, core and insulation structure .
If any damage is suspected, the following tests must
be made:
c.l . A ratio test should be made on all windings and
tap positions. If any measurement is off ratio by more
than
0 .5%,
should be made of the windings in question and com­
pared with factory test values.
resistance and temperature measurements