油纸绝缘老化过程中典型缺陷局部放电发展规律的研究

发布时间：2018-05-30 16:05

本文选题：油纸绝缘 + 老化　；参考：《华北电力大学》2017年硕士论文

【摘要】：电力变压器是保障电力系统安全稳定运行的关键设备,其内部主要绝缘形式为油纸绝缘,其健康状况直接关系到整个电网的运行安全。局部放电是变压器绝缘被破坏的主要原因之一,同时也是表征绝缘破坏程度的重要参考和表现形式,利用局部放电研究油纸绝缘变压器内部绝缘放电的发展过程,并对放电严重程度进行状态评估具有一定的现实意义。油纸绝缘在运行过程会受到热、电、环境、机械等因素的影响而发生绝缘老化,根据大量实际运行故障可知,绝缘性能的劣化是导致电气设备失效的主要原因。故此,本文针对不同老化程度油纸绝缘典型缺陷下局部放电的发展过程和特征进行了研究。对绝缘纸板进行加速热老化处理,得到不同老化程度的纸板,等效模拟变压器正常运行不同年份的绝缘老化情况;搭建了绝缘纸板典型缺陷下局部放电实验平台,构建了沿面放电和针板放电两种典型的放电模型,对绝缘纸板进行长时间局放试验;通过局部放电巡检仪采集数据,得到纸板从局放开始到局放击穿整个阶段的最大放电量、放电重复率、平均放电量等参数,结合统计参量和试验现象将其整个阶段分为三个阶段,分别为放电起始、放电发展、放电危险阶段;结合变压器实际运行情况,在考虑运行温度的影响,分析不同老化程度下油纸绝缘局部放电的发展规律。对四个不同温度条件下不同老化程度纸板的发展过程进行记录,探究综合温度和老化两种因素对局部放电发展的影响。结果表明:在起始阶段,老化对放电发展影响不显著;在放电发展和危险阶段,随着老化程度的增加,放电发展速度同样增加,平均放电量、放电重复率、最大放电量等特征参数变大;在高温下,老化对油纸绝缘局部放电发展的影响更为显著,温度越大,不同老化程度造成的放电特征量参数差异越大。
[Abstract]:Power transformer is the key equipment to ensure the safe and stable operation of power system. Its main insulation form is oil-paper insulation, and its health is directly related to the operation safety of the whole power network. Partial discharge (PD) is one of the main causes of transformer insulation failure, and is also an important reference and expression form to characterize the degree of insulation damage. The development process of internal insulation discharge of oil-paper insulation transformer is studied by partial discharge. It is of practical significance to evaluate the severity of discharge. Oil paper insulation will be affected by heat, electricity, environment, machinery and other factors during operation. According to a large number of actual operation failures, the deterioration of insulation performance is the main reason leading to the failure of electrical equipment. Therefore, the development process and characteristics of partial discharge (PD) under typical defects of oil-paper insulation with different aging degree are studied in this paper. Through accelerated thermal aging treatment of insulating paperboard, different degree of aging paperboard was obtained, equivalent simulation transformer normal operation of different years of insulation aging situation, build insulation board typical defects of partial discharge experimental platform, Two typical discharge models, surface discharge and needle board discharge, were constructed to carry out long time partial discharge test on insulating paperboard, and the maximum discharge amount from partial discharge to partial discharge breakdown was obtained by collecting data from partial discharge inspection instrument. The discharge repetition rate, average discharge quantity and other parameters, combined with statistical parameters and experimental phenomena, are divided into three stages, namely, discharge initiation, discharge development, discharge hazard stage, and actual operation of transformer. Considering the effect of operation temperature, the development law of partial discharge of oil-paper insulation under different aging degree is analyzed. The development process of paperboard with different aging degree under four different temperature conditions was recorded and the effects of comprehensive temperature and aging on PD development were investigated. The results show that the effect of aging on discharge development is not significant at the initial stage, and at the stage of discharge development and danger, the rate of discharge development increases with the increase of aging degree, and the average discharge quantity and discharge repetition rate increase. The influence of aging on the development of partial discharge of oil-paper insulation is more obvious at high temperature. The larger the temperature, the greater the difference of discharge characteristic parameter caused by different aging degree.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM855

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