Westinghouse PS-1002, Инструкция, Страница: 25 / 36

ardized units. To install the switchgear adapter, first re­
move the adapter housing if it is shipped installed on the
transformer and then align the transformer with the
switchgear. When aligned, there should be 1 7 inches be·
tween the face of the transformer throat and the face of
the switchgear throat, and the centerline of the switch­
gear throat should coincide with the centerline of the H2
or X2 bushing in the transformer throat. Refer to the
transformer outline, outline details and station plan
drawings.
Next, bolt the flexible connectors to the switchgear
bus b ars. The number of flexible connectors supplied are
determined by the transformer current and not by the
current rating of the bus bar. Check the length of flexi·
ble connectors. There should be approximately 0.375
inch ( 1 0 mm) slack to permit some movement of the bus
bars to expansion and contraction and possible settling of
the transformer. Next, make the ground bus connection
between the transformer an d switchgear. Before reinstall·
ing the adapter housing, check electrical clearances as
indicated on the outline drawing and the tightness of con­
nections and supports. Complete the installation by as·
sembling the housing. Install the adjustable plate so that
the switchgear throat is sealed by the gasket.
6.6
Pr
e
paratio
n
for Energization
The following are instructions that must be followed
when preparing the transformer for energization. These
instructions provide minimum requirements to determine
the transformer's readiness for service. Check off e ach
section as it is completed .
1 . (
) Pressure Test
Check the integrity of the transformer tank by introduc­
ing dry air or dry nitrogen through the pressure test fit·
ting (this may be identified as the air test valve or gas
sampling valve on the transformer outline) until a positive
internal pressure of 3 to
4
psig is established. Allow the
tank to stand for one to two hours, then examine the tank
an d fittings for leaks.
A leak above the liquid level can be
located by applying a soap solution to all joints, pipe fit·
tings and cable connections. The transformer must be
de-energized when checked by this method.
When the pressure test is complete, reduce the internal
pressure.
2 . ( ) Insulating Liquid Test
Before energizing the transfom1er , the liquid must be
tested in accordance with Section 8 . I . The dielectric
strength of new liquid must be 26 KV or higher.
3 . (
) Insulation Meggar Test
23
To insure that no grounding of the windings exists, a
1 000 volt meggar test and a power factor test should be
made. Refer to Section 8.3 for allowed values of insula­
tion resistance. Compare measured insulation power
factor to the values measured at the factory.
4.
( ) Ratio Test
A ratio test should be made at all tap positions to insure
proper transformer ratios and tap changer connection .
5 . ( ) C ontinuity Test
There should be a continuity check of all windings. If
possible, measure the winding resistance and compare to
the factory test values. An increase of more than 1 0%
could indicate loose internal connections. Use a wheat·
stone or Kelvin Bridge
not an ohmmeter to measure
resistance.
6. ( ) Connections
Proper connections must be made before the transformer
is energized. Check all electrical connections to be sure
they are made to the correct terminal and are mechan­
ically secure. Check the following items:
DO NOT CHANGE CONNECTIONS ON A TRANS­
FORMER THAT IS ENERGIZED NOR MAKE ANY
CONNECTIONS EXCEPT AS AUTHORIZED BY THE
NAMEPLATE OR CONNECTION DIAGRAM. TO DO
SO WILL CAUSE DANGER TO LIFE AND DAMAGE
TO PROPERTY.
( ) a) Line connections must be made without
placing more than 1 00 pounds cantilever force on Type
RCP, Type
RJ
( 1 5 KV and below) and all cast resin
and cast resin welded bushings. Above 1 5 KV, exter­
nal connections must not impose strains on the bush­
ing in excess of those specified by Table 8, ANSI
STANDARD C76.2 - 1 977. Bushings should be checked
for cleanliness at time connections are made and
cleaned if necessary .
CAUTION
A loose connection will result in a hot joint causing daD1·
age to the adapter and could cause transformer failure.