高压开关柜典型缺陷局部放电TEV特征的研究

Analysis of TEV Caused by Partial Discharge of Typical Faults in HV Switchgear

高压开关柜局部放电会在其金属外壳上产生对地电位,称之为暂态对地电压(TEV),它是一种有效的局部放电检测手段,但是目前开关柜TEV信息只局限于平均幅值,缺少有效特性信息辨识开关柜的缺陷。为了得到更多的局部放电TEV特征信息,笔者研制了一套TEV传感器及检测系统,建立了开关柜TEV测量平台,采用TEV系统对3种典型开关柜放电模型进行了测量和分析,获取了典型缺陷放电情况下TEV的散点图和统计图谱。研究结果表明:所研制的TEV传感器(带宽为5 kHz^80 MHz)可以对放电脉冲信号具有良好的响应特性,经过与脉冲电流法对比得知,TEV作为检测手段可以有效地获取局部放电信息,同时保留了能够反映缺陷类型的放电特征;统计不同缺陷情况下局部放电TEV信息所得到的柱状图谱具有明显区别,TEV特征可以作为为开关柜缺陷识别的有效依据。

The transient voltage between the metal enclosure of HV switchgear and the earth caused by partial discharge（PD） is named transient earth voltage （TEV）, which can be used for efficient PD on-line detection. However, the application of TEV is limited to its average amplitude because of lack of effective characteristic information for routine fault recognition. In order to detect PD in HV switchgear more effectively and distinguish fault types more accurately, the authors designed a TEV sensor and a TEV detection system for HV switchgear, and used the TEV detection system to record the TEV information corresponding to three typical PD models in HV switehgears. Thus, the TEV statistical maps and scatter diagrams corresponding to the PD of three typical faults were obtained. The results indicate that the bandwidth of the TEV sensor is 5 kHz to 80 MHz, and it has excellent response to PD pulse signals. TEV can be used for detecting the features of various faults, and the TEV scatter diagrams corresponding to three typical fault models are obviously different. Since the TEV signals corresponding to three typical PD models show significant differences, TEV can be applied to recognition of fault type in HV switchgear.