A Practical Study on Application of Semiconducting Glaze Insulators to Transmission Lines

This paper covers the results of investigations of the various electrical characteristics of 10-in porcelain suspension insulators with a semiconducting glaze. The runaway withstand voltage is shown almost proportional to the number of insulator units in a string. To get an almost uniform distribution along a string the impedance of the units should be lowered as the number of the units increases. Runaway withstand voltage characteristics under adverse condition and margin against working voltage are also examined. The performance of contaminated semiconducting glaze insulators under cold switch-on condition is quantitatively investigated.