Electrical insulators in 22kV distribution system of the Provincial Electricity Authority (PEA) are mostly porcelain insulator types that consist of suspension, line post, and pin insulators.

22kV pin insulators

The types of distribution lines pollution have
◆ industrial contaminants
◆ Salt fog
◆ Natural dust

Experience shows that pollution flashover is one of the main natural calamities harming and affecting the voltage stability and reliability of distribution system.

We do some 22kV pin insulator tests results obtained from artificial pollution tests according to IEC 60507 with pin post and pin type insulators of medium system under same test conditions.

The salt fog test results indicate that the pollution flashover performance of pin post insulator is less than to 50 percent of wet power frequency withstand voltage at equivalent salt deposit density (ESDD) = 0.5 mg/cm2 and the leakage current (LC) of pin insulator increased to 10.2 mA at ESDD = 0.5 mg/cm2 at nominal voltage.

In the experiment indicate that AC pollution flashover performance of pin post insulator has better than pin insulator in the serious pollution area.

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