AC Flashover Performance of Porcelain Insulators in Distribution Systems

Wichet Thippresert and Peerapol Jirapong


Flash Over, Insulation, Insulators testing


This paper presents an experiment on the different artificial pollution tests based on IEC 60507. The insulators, in the chamber for tests, used the standard medium system 22 kV. The insulators were tested with each type consisting of leakage current (LC) and flashover voltage (FOV) performance of the coating of the insulator surface, with and without semiconductor. The salt fog test results showed that FOV performance of the pin post insulator with surface without coating is less than 38 percent of dry test FOV level at equivalent salt deposit density (ESDD) = 0.5 mg/cm2. The LC of Line post insulator of a surface without a coating is less than three types of porcelain insulators, in the medium system, with 10 mA at ESDD = 0.3 mg/cm2, at a nominal voltage. This data will be useful as a guideline in cases to take insulators surface coating by the semiconductor of distribution system, to reduce the maintenance cost. Moreover, it will be useful to select or design the suitable insulators for use in polluted areas.

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