16
TR A N S FOR M E R BUS H I NG S T Y PE G S B
T EC H N I C A L G U I D E
—
Conductor loading and mechanical
loading
Conductor loading
The GSB bushings fulfill the temperature rise test
requirements according to IEC for the currents in the table
below. The short-time current is also calculated according to
IEC 60137 and listed in Table 6.
Overloading of bushings acc. to IEC
If the conductor for the bushing is selected with 120 % of
the rated current of the transformer, the bushing is
considered to be able to withstand the overload conditions
stated in IEC 60076-7 when following the directions: for long
time and short time emergency loading the oil temperature
must be 115 °C max. and the daily mean oil temperature
must be 90 °C max.
For overload conditions other than above mentioned IEC
overload, contact the supplier for permissible currents and
temperatures.
Short-time current
The rated thermal short-time current (I
th
) is calculated
according to IEC 60137.
—
Table 9. Short-time current.
Type GSB
Rated current
A
Short-time
current (I
th
)
kA, rms, 2 s
Dynamic
current (I
d
)
kA, peak
245
2000
100
250
3150
100
250
362
1600
100
250
3150
100
250
420
1600
100
250
2500
100
250
550
1600
100
250
2500
100
250
Mechanical loading
The cantilever operational and test loads are given in Table 7.
The force is applied at the center of the outer terminal of the
bushing. For extraordinary requirements which include
earthquakes, extreme environmental conditions and heavy
equipment, consult the supplier. The tests are performed in
accordance with IEC 60137 and IEEE C57.19.00. All cantilever
loads exceed IEC 60137 Level II and IEEE C57.19.01-2000.
—
Table 10. Mechanical loading.
Type GSB
Max. cantilever
operating load
for vertical
mounting
kN
Max. cantilever
operating load
for horizontal
mounting
kN
Max. cantilever
test load
kN
245
2.8
2
5.6
362
6.0
4
12
420
6.5
4
13
550
6.5
4
13
Summary of Contents for GSB 245
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