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T R A N S F O R M E R B U S H I N G S T Y P E G S A - O O T E C H N I C A L G U I D E
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Design
The solid GSA-OO bushing is completely dry and
based on a Resin Impregnated Paper (RIP) core.
The connection system consists of either flexible
or solid pull through conductors with the outer
terminal integrated with the conductor/inner
terminal. The bushings are fitted to the
transformer by means of a cast aluminium flange
with an integrated test tap.
The GSA bushings are produced by winding a
crêped paper web onto a mandrel, with
aluminium foil inserts for electrical stress control.
The core is vacuum impregnated and cured giving
a partial discharge free bushing with low tan δ
(dissipation factor). After curing, the core is
machined and the flange is fitted.
During the design work hard focus has been put
into achieving a compact and lightweight bushing
and to reduce the number of parts to a minimum
in order to achieve highest possible reliability of
1.
Outer terminal
2.
Test tap
3.
Mounting flange
4.
RIP core
5.
Solid conductor
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01 Transformer bushing type GSA-OO.
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the product. An example is that the fixing and
sealing system for the terminal has been
designed to integrate a shielding function. Thus it
is not necessary to apply a separate shield at the
top of the bushing, unless it is needed for
shielding the connection to the terminal itself.
With the outer and inner terminals integrated to
one piece, the conventional current interface
between these parts has been eliminated.
Standards
The GSA bushing is designed and tested
according to IEC 60137 and IEEE C57.19.00/01 in
applicable parts.
Features and benefits
• Solid – Reduced risk for fire, any mounting angle
possible, oil leakage from the bushing
eliminated, no monitoring of pressure and oil
level.
• Seals the transformer – Reduced risk for fire,
risk for oil leakage from the transformer
reduced.
• Non-shattering materials – Protection of
personnell and equipment, easy handling, safe
transport - also when mounted on the
transformer, high seismic withstand
• Light weight, compact – Easy handling, small
requirements on space inside transformer, low
life cycle environmental impact.
Transportation and long term storage
The bushing is surrounded by a sealed moisture-
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proof wrapping material together with a drying
agent upon delivery.
The supplied protective wrapping shall not be
opened if the bushings are intended to be stored.
After transformer test, it is also important to
reseal the bushing with the supplied protective
wrapping or a similar moisture-proof wrapping,
together with a drying agent. The wrapping
works as protection for transportation and
storage (< 6 months). Note that bushings with
standard wrapping shall be stored protected
from precipitation.
For longer storage times (>6 months) a container
have to be ordered separately.
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