Studies on the effects of moisture and ageing on charge de-trapping properties of oilimpregnated pressboard based on IRC measurement  

作　　者：Nasirul Haque Sovan Dalai Biswendu Chatterjee Sivaji Chakravorti 

机构地区：[1]Department of Electrical Engineering,Jadavpur University,Raja S.C.Mullick Road,Kolkata,West Bengal,India [2]NIT Calicut,Calicut,Kerala,India

出　　处：《High Voltage》2019年第2期151-157,共7页高电压（英文）

基　　金：CSIR,Government of India,and grant of DST,Government of India under the SERB scheme,file no.EEQ/2016/00046;FIST grant of DST,Government of India(grant no.SR/FST/ETI-362/2014).

摘　　要：The dielectric properties of oil-paper insulation degrade due to moisture ingression and ageing.This degradation significantly impacts the space charge accumulation and charge trapping behaviour in the insulation,which are vital parameters for insulation health under the high-voltage direct current environment.In this work,an improved model based on the isothermal relaxation current(IRC)has been developed to study the charge trapping behaviour of an oil pressboard under the influence of moisture and ageing.The conventional IRC model considers the total relaxation current because of charge de-trapping only.However,in the case of a composite dielectric like oil pressboard,dipolar relaxation also affects the relaxation current.In this work,a methodology has been proposed to investigate charge de-trapping behaviour of oil-pressboard insulation considering the dipole relaxation process from IRC measurements.For this purpose,frequency domain spectroscopy measurements and IRC measurements have been performed on oil-impregnated pressboard specimens carefully prepared in the laboratory having different ageing conditions and moisture contents.Results presented in this work depict that charge trapping parameters,i.e.the trap depth and trapped charge distribution are highly affected both by ageing and moisture.It was observed that ageing leads to the generation of deeper traps,while moisture mainly enhances the density of shallow traps.

关 键 词：MOISTURE TRAPPING CHARGE 

分 类 号：TM855[电气工程—高电压与绝缘技术]