ABB GSB 245, Technical Manual

TR A N S FOR M E R BUS H I NG S T YPE G S B 

T EC H N I C A L  G U I D E

5

GSB is a Resin Impregnated Paper (RIP) bushing 
intended for immersed oil – air service. The 
bushing is built up around an aluminium center 
tube on which the condenser core is wound. The 
core is wound from crepe paper with aluminium 
foil inserts for electrical stress control. The core 
is impregnated and cured in a vacuum, giving a 

partial discharge free bushing with low tan δ 

(dissipation factor). After curing, the core is 
machined and a flange and an insulator are fitted. 
The insulator is made of composite or porcelain. 
The space between the RIP core and the insulator 
is then filled with an insulating gel.

As a current conductor, GSB uses the center tube 
on which the RIP core is molded. The oil side 
connection can be made with a draw-rod system, 

an inner terminal for draw lead, or a fixed bottom 
contact. The bottom contact is normally delivered 
with a standard end-shield. An alternative bottom 
contact is available to fit customized end-shields 
for draw rod only. For the air side connection 
there are studs available in a number of standard 
configurations, but it can also be modified to suit 
any connection need.

The bushing is designed to be mounted at an 
angle not exceeding 90° from the vertical. The 
standard colour of the composite insulator is 
ANSI 70 light gray.

Standards

The GSB bushing is designed and tested 
according to IEC 60137 and IEEE C57.19.00/01.

Features and benefits

•  Solid (Oil free) – Reduced risk of fire. Oil leakage 

from the bushing eliminated.

•  Seals the transformer – Reduced risk of fire. 

Risk of oil leakage from the transformer 
reduced.

•  Non-shattering materials – Silicone insulator. 

Protection of people and equipment.

•  Easy handling – Safe transport - even when 

mounted on the transformer.

•  Light weight, compact – Easy handling, small 

space requirements inside transformer, low life 
cycle environmental impact.

•  Seismic qualified by shake table tests.

Transportation and long term storage

On the oil side of the bushing, a metallic sealing 
container, containing drying agent, is fitted. The 
sealing container will protect the oil side from 
moisture absorption. It is important that the 
sealing container is fitted during transport and 
storage. The container is suitable both for short-

time storage (≤6 months) and long-time storage. 

The bushing can be stored outdoors when the 
sealing container is fitted.

As an option, the moisture barrier “RIPCOAT” can 
be supplied as extra protection when the 
container is not mounted.

—

Design

—
01 Transformer bushing type GSB oil – air.

1.  Outer terminal
2.  Top piece
3.  Composite or 

porcelain insulator

4.  Test tap
5.  Mounting flange
6.  RIP core
7.  Bottom contact

4

5

3

1

7

2

6