Ceramic insulator power-frequency puncture test
The voltage of power-frequency puncture is a factor for ceramic punctured insulators. Ceramic insulator power-frequency puncture test can be done by insulator manufacturer.
Ceramic insulator, after having been cleaned and dried, shall be completely immersed in a tank containing a suitable insulating medium to prevent surface discharges on them. If the tank is made of metal, its dimensions shall be such that the shortest distance between any part of the ceramic insulator and the side of the tank is not less than 1,5 times the diameter of the largest insulator shed. The insulating medium temperature shall be at about room temperature.
It is not possible to define exactly the properties of the insulating medium, but one desirable property is a slight conductivity .The insulator test voltage shall be applied between those parts which normally have the operating voltage between them. During immersion in the insulating medium, precautions shall be taken to avoid air pockets under the sheds of the insulator. The test voltage shall be raised as rapidly as is consistent with its value being indicated by the measuring instrument to the specified puncture voltage. No puncture shall occur below the specified puncture voltage.
To provide information, and when specially requested at the time of ordering, the voltage may be raised until puncture occurs and the puncture voltage recorded.
These are premise and attention items about Ceramic insulator power-frequency puncture test. About ceramic insulator power-frequency puncture test, porcelain pin insulator, porcelain pin post insulator and porcelain disc suspension insulator these type insulators are all punctured ceramic insulator and should be done this test. Except 12KV station post insulator for grid power network, 35KV and other voltage station post insulators will be done power frequency withstand test.