交流电压下油纸绝缘针板放电特性  

Partial Discharge Characteristics of Point-plane Model in Oil-paper Insulation Under AC Voltage

作　　者：廖瑞金[1] 段炼 汪可[1] 杨丽君[1] 袁磊[1] 郭超[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030 [2]广州荔湾供电局,广州510620

出　　处：《高电压技术》2014年第3期648-654,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2009CB724505-1);国家自然科学基金(51277187)~~

摘　　要：为探究油纸绝缘针板放电发展过程和老化对放电特性的影响,在实验室条件下,通过油纸绝缘130℃加速热老化试验,以绝缘纸板聚合度为表征老化程度的特征参量,得到了不同老化阶段的油纸绝缘样品。基于脉冲电流法,测量了交流电压下不同老化状态油纸绝缘针板模型局部放电信号,分析了从起始至预击穿过程中局部放电相位分布模式的幅值分布H(q,φ)谱图,并讨论了油纸绝缘老化对局部放电H(q,φ)谱图、放电量、放电次数和统计参数的影响。研究结果表明:针板电极局部放电H(q,φ)谱图中放电分布在正、负峰值附近,工频正半周的脉冲幅值、个数均分别大于负半周,且正半周的H(q,φ)谱图放电随电压升高呈现"倒V型";平均放电量-相位分布Hqave(φ)正半周的偏斜度Sk+随电压的升高呈下降趋势,且在油纸绝缘样品达到预击穿阶段Sk+变为负值,因此Sk+可用于评估油纸绝缘针板电极模型下的缺陷发展状态;随着油纸绝缘的老化,导致油中老化产物增多,进一步畸变了场强,老化后的油纸绝缘样品正半周局部放电次数明显增多,平均放电量、最大视在放电量增大。In order to explore the process of partial discharge （PD） in point-plane model and the influence of aging on PD, we obtained oil-paper insulation samples of different aging stages, which were denoted by the degree of polymerization of insulation paper, through artificial aging processing under 130 ~C in laboratory. Then, by the pulse current method, we measured PD signals of point-plane model in oil-paper insulation under AC voltage. After analyzing the evolution of phase-resolved partial discharge （PRPD） H（q, φ） spectrum from the inception stage to pre-breakdown stage of PD, we discussed the influence of aging on H（q, φ） spectrum, maximal apparent charge, average apparent charge, PD number, and statistical parameters. The results show that PDs concentrate around positive and negative peaks in H（q, φ） spectrum, while PDs of applied voltage＇s positive half-cycles are greater than those of negative half-cycles in both amplitude and amount. Meanwhile, the H（q, φ） spectrum of positive half-cycles turns into an inverted ＇V-shape＇ gradually with in- creasing voltage. In addition, in positive half-cycles, parameter skewness Sk＋ of average discharge magnitude-phase distribution Hqave（φ） shows a downward trend with the increase of voltage, and Sk＋ shifts to negative when the samples get to pre-breakdown stage, so Sk＋can be used to assess the defect development in oil-paper insulation of point-plane model. With the development of oil-paper insulation aging, the field strength is further distorted due to the increase of aging products, which leads to the rising of maximal apparent charge and average apparent charge, as well as the number of PD pulse in positive half-cycles.

关 键 词：电力变压器 油纸绝缘 热老化 局部放电 脉冲电流法 局部放电相位分布图谱 

分 类 号：TM855.1[电气工程—高电压与绝缘技术]