局部放电作用下变压器油纸绝缘劣化缺陷发展规律的研究

发布时间：2018-02-26 00:34

本文关键词： 变压器油纸绝缘局部放电加速电劣化碳化通道白斑　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：变压器油纸绝缘局部放电大致可划分为三类：纸板／纸沿面爬电、纸板／纸内部放电、油中电晕放电。其中以纸板沿面爬电危害最大,纸板／纸内部放电次之,油中电晕放电的危害相对较小,本文重点研究前两种类型放电。为了研究变压器油纸绝缘材料内部局部放电劣化缺陷的发展规律及其与局部放电特征量的关联性,构建了匝间局部放电模型,进行了多组不同加压时间段的恒压试验,并记录了试验过程中的局部放电信号。利用匝间绝缘纸带可层层拆解的结构特点,获得了匝间绝缘在加速电劣化下碳化通道发展的统计性规律。研究结果表明,恒压加速电劣化作用下匝间油纸绝缘局部放电缺陷即碳化通道沿宏观电场的纵向发展过程呈现增长、停滞和击穿三个基本阶段；脉冲重复率和脉冲1秒钟内总放电量可以宏观表征匝间油纸绝缘电劣化缺陷的发展状况,为油纸绝缘局部放电严重程度阶段性的准确划分提供参考依据。爬电放电被认为是变压器内部危害性最大的绝缘故障类型,往往在正常的运行条件下就可造成灾难性的事故。现有的试验研究成果均未涉及爬电过程中绝缘缺陷与局部放电信号特征量之间的关联性问题。本文采用针板试验模型,研究了油浸纸板层间爬电的试验现象,定量地描述了爬电绝缘缺陷即白斑的发展规律。分析结果表明：利用白斑起始前后脉冲相位分布谱图的形状轮廓及统计特征参数的阶跃突变特点,可以获得白斑起始的先兆表征；脉冲重复率和脉冲1秒钟放电量这两个局部放电特征量均可表征树枝状白斑的发展过程。
[Abstract]:Transformer oil-paper insulation partial discharge can be divided into three categories: paperboard / paper side creeping, paperboard / paper internal discharge, corona discharge in oil. The damage of corona discharge in oil is relatively small. This paper focuses on the first two types of discharge. In order to study the development rule of partial discharge deterioration defect in oil-paper insulation material of transformer and its relation with partial discharge characteristic quantity, the inter-turn partial discharge model was constructed, and the constant voltage test was carried out for many groups of different pressure periods. The partial discharge signals during the test are recorded. The statistical law of the carbonization channel development of inter-turn insulation under accelerated electric degradation is obtained by using the structure characteristics of interturn insulator paper tape which can be disassembled layer by layer. The defect of partial discharge of inter-turn oil-paper insulation under constant voltage accelerated electric deterioration is that the carbonization channel increases along the longitudinal development process of macroscopic electric field, which is the three basic stages of stagnation and breakdown. The pulse repetition rate and the total discharge in one second can be used to characterize the development of the electric deterioration defect of inter-turn oil-paper insulation, which provides a reference for the accurate division of the severity of partial discharge in oil-paper insulation. Creeping discharge is considered to be the most harmful type of insulation fault in transformers. Catastrophic accidents are often caused under normal operating conditions. The existing experimental results do not deal with the relationship between insulation defects and partial discharge signal characteristics during creeping. In this paper, a needle-board test model is used. The experimental phenomenon of interlayer creeping of oil-impregnated paperboard was studied. The development law of white spot, which is the defect of creeping insulation, is described quantitatively. The results show that the shape profile of pulse phase distribution spectrum before and after the initiation of white spot and the step mutation characteristics of statistical characteristic parameters are used. The characteristics of pulse repetition rate and pulse discharge in one second can be used to characterize the development of dendritic white spot.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855

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