GE Industrial Solutions Seconday Substation Transformer User Manual

Industrial Transformers
Secondary Substation Transformers

INSTRUCTION BOOK

CARE AND MAINTENANCE OF OIL-IMMERSED

(R-TEMP-OR SILICONE IMMERSED) TRANSFORMERS

TABLE OF CONTENTS

Page

SHIPPING………………..............................…………….....................................................…..2

INSPECTION ON RECEIPT………….……………….....…………...........................................…. 2

HANDLING………………......................................................…………...............................…. 2

INTERNAL INSPECTION ..……………...............................................…………....................….2

STORAGE …………………...............….........................................................…………......…..3

LOCATION…………………….............…...............................................................…………….3

SERVICE SET UP …………...............………....................................................…………….….4

SERVICE START UP ………...............................................................……………………….….4

LOADING………………..…...............................................................................…………...….5

PERIODIC INSPECTION….............................................................……………………………...5

MAINTENANCE DURING PERIODS OF SHUTDOWN…………………………..................……….5

ACCESSORIES -

Sudden Pressure Relief Device ……….……………………………………….…….6

Pressure Vacuum Bleeder Devices ..................................................…......6

Bushings ...……………………………………………………………………….… 6
Forced Air Equipment ..………….…………………………………………….….. 6
Tap Changers ….…………………..………………………………………….………8

Thermometers …...………………...........................................................….. 8

Liquid-Level Indicators ………………….................................................….... 8

METHOD OF DRYING TRANSFORMERS……………….......................................………..…… 8

FILLING WITH INSULATING LIQUID…………………............................................................… 9

For Technical Support please call:

011-528-156-2582
011-528-156-2168

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SHIPPING

A. COMPLETE TRANSFORMER

Distribution transformers are shipped
completely sealed. Core and coils are
assembled in a tank with the insulating liquid
covering the coils.

This method of construction preserves the
quality of insulation, the cooling and
insulating liquid by preventing contamination
from external sources.

INSPECTION ON RECEIPT

When a transformer is received, a thorough
external inspection should be made before
the unit is removed from the railroad car or
truck. If there is evidence of damage and/or
indication of rough handing in transit, and
inspector representing the carrier should be
requested and the manufacturer immediately
notified.

NOTE: An internal inspection is necessary
only if internal damage is suspected because
of external indications of rough handling.

If the delivering carrier is willing to permit
internal inspection of the transformer on the
railroad car or truck prior to unloading, without
requiring consignee’s signature on the
delivery slip, a representative of the
manufacturer should be called and an internal
inspection made as outlined in “Internal
Inspection”.

If the delivering carrier will not permit internal
inspection of the transformer on the railroad
car or truck, note on the acceptance slip for
the shipment that there are “possible internal
and/or hidden damages”, and file a claim
immediately for possible hidden damage.
When the transformer has been removed to
the installation site or some other convenient
location to permit inspection of the internal
assembly for damage in transit, proceed as
outlined in “Internal inspection”. Request that
a representative of the carrier be present
during the inspection.

The transformer should always be handled in
the normal upright position unless information
from the manufacturer indicates that it can be
handled otherwise. Where a transformer
cannot be handled by a crane, it may be
skidded or moved on rollers into place,
depending upon compatibility of transformer
base design and the type of surface over
which it is to be moved. During the handling
operation, care must be taken to prevent
overturning.

When a transformer is shipped it is usually
ready to be set in place after the crating and
shipping braces are removed. Bushings and
accessories which are shipped separately
should be thoroughly protected against
moisture until they are installed. Proper
precaution must be taken during installation
of these parts to protect the transformer
against moisture.

B. LIFTING WITH SLINGS

Lifting lugs and eyes are designed to be lifted
with a maximum sling angle of 30° from the
vertical. For lift angles of greater than 30°
from the vertical, spreader bars must be used
to provide a vertical lift on the lugs.

C. RAISING WITH JACKS

Jack bosses are provided on most
transformers so that the transformer can be
raised by means of jacks. On those
transformers not equipped with bosses, the
jacks may be placed under the transformer
bottom plate at designated points. The
manufacturer’s drawings should be consulted.

Do not attempt to raise the transformer by
placing the jacks under drain valves, pipe
connections or other attachments. It is also
recommended that these appendages are not
subjected to a man’s weight.

HANDLING

INTERNAL INSPECTION

WARNING: Avoid any accident. Be sure to

relieve tank pressure or vacuum before

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attempting to loosen and remove manhole
cover.

A. INSULATING LIQUID

Before opening a transformer, take samples
of the insulating liquid from the top and
bottom of tank and test the dielectric
strength. The dielectric strength should be
no less then 27.5 kV. If it is lower, the
transformer should not be placed in service
until the dielectric strength has been restored
by filtration.

B. CORE-AND-COIL ASSEMBLY

Lower the insulating liquid to the top of the
core-and-coil assembly and inspect the
interior to see if any damage has occurred. If
possible, DO NOT allow the coils and
insulation to be exposed to the air.

2. Small bushings if any may be left on
the cover if they are protected and
the cover is carefully handled.
Remove cover. Remove
thermometer, tap changer and liquid
gauge and all other accessories and
associated wells which project into
the tank and which might interfere
with untanking operations.

3. Use slings for removing the core-and-

coil assembly.

4. Particular care must be taken in
handling tools and other loose
articles when working with a
transformer. Metallic objects, if
dropped in the windings and allowed
to remain there, can cause a severe
fault.

STORAGE

Examine the top of the core-and-coil
assembly, all horizontal surfaces and the
underside of the cover for signs of moisture.
If there are no signs of moisture or damage,
proceed with the reassembly of the
transformer. If there are signs of moisture
inside the tank, steps should be taken to
determine the extent of it and the manner in
which the moisture entered the transformer.
Reassembly should be carried through and
the manufacturer of the equipment should be
requested to make recommendations
concerning further checks and steps for
drying out the transformer.

If the transformer appears to have been
damaged internally, or if it is desirable to
remove the core-and-coil assembly for
inspection or drying, the transformer may be
untanked as follows:

1. Remove the handhole lid and
disconnect high-and low-voltage
leads if the bushings are in position.
Remove large bushings from cover if
any.

It is advisable to locate a transformer,
complete with liquid, in its permanent location
even if it will not be placed in service for some
time. It is recommended to check the paint
finish and to repair all damaged painted
surfaces. If the transformer is shipped and
stored in dry inert gas, the gas pressure
should be maintained and periodically
tested. If an oil-filled, indoor-type transformer
is stored outdoors, it should be thoroughly
covered to keep out rain. A transformer
should not be stored or operated in the
presence of corrosive vapors or gases, such
as chlorine.

Should it become necessary to store
accessories for a long period of time, they
should be stored in a clean, dry place or the
manufacturer should be contacted for explicit
instructions on the storage of individual
pieces.

LOCATION

Accessibility, ventilation and ease of
inspection should be given careful
consideration in the location of transformers.

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