Study on electrical strength of suspension insulators in steep impulse voltage range

High and steep lightning surge voltages sometimes cause the electrical punctures of suspension insulators. Microscopic analysis clarifies the electrical breakdown mechanism of the ceramic material. V-t characteristics of the insulators are closely examined. The chance of a puncture depends on the dimensions of the insulators, steepness of the impulse voltages and the number of impulse occurrences. Empirical equations relating to these parameters has been established based on laboratory test results. Calculations show no risk of puncture on quality insulators for impulse voltages of 2500 kV//spl mu/s steepness, the standards requirement.