温度梯度对直流电压极性反转过程中瞬态电场的影响  

Effects of Temperature Gradient on Transient Electric Field Under DC Voltage Reversal

作　　者：陈曦[1] 王霞[1] 王增彬[1] 吕泽鹏[1] 吴锴[1] 彭宗仁[1] 成永红[1] 

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高电压技术》2010年第5期1222-1227,共6页High Voltage Engineering

基　　金：国家自然科学基金(50907050);高等学校科技创新工程重大项目培育基金(707053)~~

摘　　要：高压电缆运行中由于导体发热而引起绝缘由内到外形成温度梯度。直流电压下温度梯度的存在必然会影响电荷的注入和迁移、加剧了位于绝缘层外表面的电荷积聚和场强畸变,降低绝缘击穿强度,也造成了电缆在断电或电压极性反转时的早期破坏。为此,基于电声脉冲(PEA)法,测量了聚乙烯板状试样在不同温度梯度场、50kV/mm直流电场协同作用下加压和极性反转过程中的空间电荷分布和最大瞬态场强。结果表明:温度梯度场-直流电场协同作用下,最大稳态电场出现在试样低温侧;而温度梯度场-电压极性反转协同作用下,最大瞬态电场却出现在高温侧。Temperature gradient through the cable thickness occurs due to Joule heat arising from the electric current in the HV cable conductor, which tends to affect the injection and migration of charge.Consequently,based on the pulsed electroacoustic（PEA） method,space charge accumulation and maximal transient electric field distortion were studied under different temperature gradient during applied 50kV/mm DC stress together with the applied voltage reversal.The experimental results show that the maximal steady-state electric field appears near the low temperature electrode when temperature gradient and DC stress are imposed upon simultaneously.However,the maximal transient electric field appears near the high temperature electrode when temperature gradient and voltage reversal are imposed upon.

关 键 词：温度梯度 瞬态场强 极性反转 聚乙烯 电声脉冲 空间电荷 

分 类 号：TM85[电气工程—高电压与绝缘技术]