摘要
空间电荷是方波电场下绝缘介质老化的重要因素,然而方波电场极性反转时间为ns~μs级,这给直接检测方波电场下绝缘介质内部的空间电荷带来了困难。为实现方波电场下的直接检测,分析了电声脉冲法检测系统中核心设备性能参数对方波电场下空间电荷检测的影响,并采用自动均分移相原理实现了方波电场下空间电荷的直接动态检测,然后通过对10k V/mm方波电场下聚酰亚胺膜的空间电荷直接检测,初步探讨了方波电压上升沿时间对空间电荷的影响。结果表明:电声脉冲法检测系统中保护电阻R1和耦合电容C1、试样电容C2构成一个低通滤波回路,时间常数τ过大可能导致试样上承受方波电压波形的严重失真,可通过减小保护电阻R1和耦合电容C1的方法有效降低系统时间常数τ,从而实现对方波电场瞬时极性反转过程中试样内部的空间电荷检测;利用自动均分移相原理可实现10 kV/mm方波电场下聚酰亚胺膜中空间电荷的高分辨率直接检测,相位分辨率达1.79°;方波上升沿时间为100μs、500μs、1 000μs时,聚酰亚胺内部在无过冲10 kV/mm方波电场下的空间电荷主要来自于下电极铝板注入的同极性电荷,在电压极性反转的过程中可快速抽出,试样内部并没有形成明显的空间电荷积累现象。
Space charge is an important factor leading to insulation aging under square wave electric field.However,it is difficult to directly detect the space charge in insulation under square wave electric field,due to the quickly polarity reverse at the level of ns toμs.In order to implement direct detection,the core parameters of space charge detection equipment in an examination system by a pulsed electro-acoustic method(PEA)were analyzed to determine their influence on space charge detection under the square wave stress.The direct dynamic detection of the space charge under the square wave stress was realized by the automatic equal phase shift principle(AEPS).The formation mechanism of space charge under the square wave stress was discussed preliminarily by detecting the space charge with polyimide film under the square wave stress of 10 kV/mm.The results show the protection resistor R1,the coupling capacitor C1,and the sample capacitor C2 constitute a low-pass filter circuit for the PEA system.A large time constantτmay cause seriously distortion of square waveform applied on tested sample.It is indicated that the space charge detection during instantaneous polarity reverse of square wave stress can be realized for the system with smallτby reducing the values of R1 and C1.The direct space charge detection with high phase resolution about 1.79°is realized under 10 kV/mm for polyimide film by AEPS principle.According to the space charge behavior under the no-overshoot 10 kV/mm square wave with the different rise time,i.e.100μs,500μs and 1 000μs,the internal space charge mainly comes from the homocharge injected from the low electrode with aluminum material.The space charge can be quickly extracted during the polarity reverse process,and no significant space charge can accumulate inside the specimen.
作者
陈亚丁
吴建东
戴畅
王亚林
尹毅
CHEN Yading;WU Jiandong;DAI Chang;WANG Yalin;YIN Yi(Department of Electrical Engineering,School of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2019年第6期1767-1774,共8页
High Voltage Engineering
基金
国家自然科学基金(51737009)~~
关键词
方波电场
空间电荷
直接检测
自动均分移相原理
电声脉冲法
square wave stress
space charge
directly detection
automatic equal phase shift principle
pulsed electroacoustic method
