Pollution performance of metal oxide surge arresters

Abstract

A metal oxide surge arrester (MOSA) under the effect of conductive pollutants presents two problems namely the insulation performance of the porcelain housing which is more or less similar to insulators working under polluteted condition. Modelling of this type of problem has drawn considerable attention of the researchers and resultq have been published in literature [1,2,3]. But the second problem as sparkover performance of the active parts consisting of coupling and grading capacitances and MO varistors is less known. Taking the consideration of coupling and grading capacitances and non-linear resistance and capacitance of element equivalent circuit becomes very complex. In literature [4] Shibuya et al. has analysed the MOSA behaviour under pollution by taking equivalent circuit diagram considering only coupling capacitance not grading capacitances. And they have not reported temperature effect. There report is limited to variation of voltage distribution with dry band length. In this paper with the help of computer program the results of the investigation on how contamination may affect internal circuitry of MOSA has been reported. Analysis has been also done for watt loss and its thermal effect on MOSA. © 1991 IEEE.