75kv High Voltage Wall Bushing

Use condition:
1 Environment temperature: highest+400C, lowest-400C
2 Maximum altitude: 1000m, higher altitude than 1000m are available on request
3 Environment pollution level: II, III, IV.

Electric test
Type test according to  GB109-1999 Technical Condition for High Voltage bushing and enterprise standard Q/SW001-2001 Technical Condition of Dry-type composite Insulated High-voltage Wall bushing for 40.5 kV, 72.5kV,126kV and 252kV. the following type test sequence are carried out.
1     High-voltage test

Rated voltage(kV)
1 min power frequency voltage withstand  (dry and humid)(kV)
Long-term power frequency voltage withstand (15min)(kV)
Lighting impulse voltage withstand (kV)
40.5
95
/
200
72.5
147
90
325
126
185(230)
160
450(550)
252
395(460)
330
950(1050)
2     Dielectric loss factor tan  :≤ 0.002
3     Temperature rise test: temperature of leading conductor is lower than 900C
4     Partial discharge level:≤10pC
4     Thermal short-time current wihstand test.
6     Cantilever load withstand test

Acceptance test and maintenance
1.       Before acceptance or operation, test the AC voltage withstand , dielectric loss and capacitance, AC voltage withstand is the 85% of factory test voltage, dielectric loss and capacitance test should be carried in the better weather to avoid humidity influence.
2.       During the operation, test capacitance once each 2 -3 years .When testing, leading conductor connected to high-voltage bushing should be as short as possible. Under the electrical condition, grounding current of sleeve end is monitored and measured.
3.       When cleaning, it is better to use water to wash or wipe using soft wet cloth to avoid scratching surface.