采用暂态对地电压法综合检测开关柜局部放电

Comprehensive Detection of Partial Discharge in Switchgear Using TEV

针对暂态对地电压(TEV)技术在实际开关柜局部放电检测中判断依据单一、检测结果可靠性不高等问题,对如何更好应用TEV技术展开研究。在分析TEV技术原理的基础上,综合应用TEV技术对高压开关柜典型缺陷的局部放电进行了检测与分析,探究了不同缺陷模型下的时域相位、脉冲数和测量阈值之间的关系并统计了不同缺陷的特征。结果表明,尖刺放电均发生在0°～90°及200°～340°,负半周中较高幅值的放电明显较少;内部放电发生在0°～90°及270°～315°,正负半周的放电随阈值的升高呈现相似的减少趋势;悬浮放电发生在0°～135°及180°～315°,与其正半周相比,负半周的放电随阈值升高而下降的更加剧烈,这些现象均与使用传统的脉冲电流法所得到的结论相一致,说明了使用TEV法对开关柜进行局部放电类型识别的可能性,为进一步的研究做准备。

In order to solve the problems such as single judgment criterion,low reliability of measurement in detection of PD in HV switchboard,we analyzed the method on how to better utilize TEV（transient earth voltage）in scientific research.Based on research results on TEV principle,comprehensive measurement was used to check and analyze typical defects in switchgear.Through researching the relationship among the temporal phases,number of pulses and threshold of measuring,and extracting the features corresponding to different typical defects,it is revealed that the needle discharge occurs at 0°～90°and 200°～340°with low appearance probability under high measurement threshold;internal discharge occurs at 0°～90°and 270°～315°,and similar decreasing trends are found under increasing of the threshold in the two regions;suspended discharge occurs at 0°～135°and 180°～315°,and has faster decreasing process in negative half periods comparing with the positive under increasing of the measurement threshold.These results accord with the conclusions which are obtained by using the traditional pulse current method.Consequently,it is possible to use TEV method to make identification of defects in HV switchboard.