6
TR A N S FOR M E R BUS H I NG S T Y PE G S B 8 0 0
I N S TA L L AT I O N A N D M A I N T EN A N C E G U I D E
1.2 Operating conditions
The table below shows the general specifications for the
GSB bushings. For conditions exceeding the specifications
below, please contact the supplier.
Table 1. General specifications:
Application:
Transformers
Classification:
Resin-impregnated paper, capacitance-graded,
outdoor immersed bushing, temperature class E
(120°C) according to IEC 60137
Ambient
temperature:
+40°C to -40°C, including minimum value
according to temperature class 2 of IEC 60137
(-50°C and other temperatures on request, subject
to agreement)
Altitude of site:
< 1000 m
Level of rain and
humidity:
1-2 mm rain/min. horizontally and vertically, as per
IEC 60060-1, and 5 mm/min. as per IEEE Std.
C57.19.00-2004 (Std. 4, conventional procedure in
USA.)
Pollution level:
According to specific creepage distance and IEC
60815 ("Guide for selection of insulators with
respect to polluted conditions")
Immersion medium: Transformer oil.
Oil temperatures for normal load:
Maximum daily mean tempe90°C.
Maximum temporary temperature: +100°C.
Oil temperatures for long- and short-term
overload:
Maximum daily mean tempe90°C.
Maximum temporary temperature: +115°C.
Maximum pressure
of medium:
100 kPa (over-pressure)
Angle of mounting: Horizontal to vertical
Voltage tap:
Dimensions according to IEEE Potential tap type
A. Ur = 6 kV
Capacitance C
2
of
the voltage tap:
< 29,400 pF
Conductor:
Center tube. Inner terminal for flexible draw lead
available on request.
Minimum creepage
distance:
27.500 mm.
Markings:
In conformance with IEC/IEEE.
1.3 Mechanical loading
The cantilever operating loads (for vertical and horizontal
mounting) and the test load are specified in Table 2. The
force is applied at the center of the outer terminal of the
bushing.
Table 2. Mechanical loads.
Mounting
angle
Max. cantilever operating
load according to IEC or
continuous cantilever
loading according to IEEE
(kN)
Max. cantilever test load
(kN)
IEC and IEEE
Vertical
7.5
15
Horizontal
3.2
6.4
For extraordinary requirements relating to earthquakes,
extreme environmental conditions and heavy equipment,
consult the supplier.
Table 3. Earthquake loading.
Seismic
standard
Allowed
earthquake load
Installation
angle from
vertical
Verified by
IEC 61463
AG5 (5 m/s
2
)
45°
Static coefficient
calculation
IEEE 693-2005
0.3 g
20°
Time history
shake table test
1.4 Spare parts
In the event of major damage to the bushing, we recommend
that it be sent back to the supplier for possible repair and
re-testing. Certain parts, which may be damaged or lost
during transport or installation, can be ordered from the
supplier.
1.5 Installation information
If the bushings are mounted on seismic-exposed equipment,
M27 fastening bolts with property class 8.8 (according to
EN-ISO 898-1) must be used on the bushing mounting
flange.
If bolts with other dimensions and property classes are used
(e.g. for low seismic exposure levels), please contact the
supplier for approval.