XLPE电力电缆局部放电信号特征及现场实测分析

发布时间：2018-03-30 19:18

本文选题：XLPE电力电缆　切入点：局部放电　出处：《天津大学》2014年硕士论文

【摘要】：交联聚乙烯(XLPE)绝缘材料具有优异的物理、化学和耐热性能,在天津电网各电压等级的电力电缆线路中已获得广泛应用。由于在电缆的生产、运输和安装过程中易引入杂质、气泡等缺陷,绝缘中会形成局部放电现象,导致XLPE电缆早期击穿,影响电力系统的供电可靠性。检测XLPE电力电缆的局部放电信号,分析放电的危害性对于保障电力系统的安全运行具有重要的理论意义和工程价值。本文首先采用过氧化二异丙苯为交联剂制备厚0.5mm的XLPE试样,搭建了内部放电、电晕放电和表面放电三种缺陷模型,通过高频电流互感器对局部放电信号实施采集。针对三种典型绝缘缺陷下的局部放电单次脉冲波形特征进行了研究,揭示了三种放电模式下单次脉冲波形频域谱的显著差异。研究了内部气隙直径,针电极长度、直径,针电极距XLPE试样表面距离等参数变化对单次脉冲波形上升沿、宽度及幅值的影响,并分别从内部放电、电晕放电和表面放电的形成物理机理出发,对上述规律进行解释。其次,针对三种典型绝缘缺陷下的局部放电脉冲序列统计特征进行研究。基于局部放电脉冲幅值出现次数(N)和放电幅值(Q)之间的关系曲线,建立了基于二维威布尔分布参数的缺陷特征谱。发现对于不同放电类型,其N-Q曲线的二维威布尔分布参数在α-β平面中的分布具有明显的聚类特性,可作为识别不同种类缺陷局部放电的特征参量。最后,采用高频电流互感器对天津市某企业35k V变电站内多个XLPE电缆终端进行局部放电检测,通过分析PRPD谱图和单次脉冲统计规律,成功发现电缆绝缘隐患。
[Abstract]:The XLPE insulation material has excellent physical, chemical and heat resistance properties, and has been widely used in power cable lines of various voltage levels in Tianjin Power Grid. Impurities are easily introduced in the production, transportation and installation of cables. Some defects, such as bubble, will form partial discharge in insulation, which will lead to early breakdown of XLPE cable, which will affect the power supply reliability of power system. Detection of partial discharge signal of XLPE power cable, It is of great theoretical significance and engineering value to analyze the harmfulness of discharge in order to ensure the safe operation of power system. In this paper, the XLPE sample with thick 0.5mm is prepared by using diisopropyl peroxide as crosslinking agent, and the internal discharge is built up. Three defect models of corona discharge and surface discharge are used to collect partial discharge signals by high frequency current transformer. The characteristics of partial discharge single pulse waveform under three typical insulation defects are studied. Significant differences in frequency domain spectrum of three discharge modes were revealed. The rise edge of single pulse waveform was studied by the variation of internal air gap diameter, needle electrode length, diameter, distance between needle electrode and surface of XLPE sample. The effects of width and amplitude, and the physical mechanism of internal discharge, corona discharge and surface discharge, respectively, are explained. The statistical characteristics of partial discharge (PD) pulse sequence under three typical insulation defects are studied. Based on the relation curve between PD pulse amplitude (N) and discharge amplitude (Q), The defect characteristic spectrum based on two-dimensional Weibull distribution parameters is established. It is found that for different discharge types, the distribution of 2-D Weibull distribution parameters of N-Q curve in 伪-尾 plane has obvious clustering characteristics. It can be used as the characteristic parameter to identify the partial discharge of different kinds of defects. Finally, the high frequency current transformer is used to detect the partial discharge of several XLPE cable terminals in 35kV substation in a Tianjin enterprise. By analyzing the PRPD spectrum and single pulse statistics, the hidden trouble of cable insulation is found successfully.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855

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