基于FDR法的变电站低压电缆局部缺陷定位方法  

Partial Defects Positioning Method of Low Voltage Cables in Transformer Substation Based on FDR Method

作　　者：王中杰[1] 杨爱晟 冯霆 陶文彪 杜娟 WANG Zhongjie;YANG Aisheng;FENG Ting;TAO Wenbiao;DU Juan(State Grid Shanxi Electric Power Company,Taiyuan 030001,China;State Grid Jinzhong Power Supply Company,Jinzhong 030600,China;State Grid Shanxi Electric Power Research Institute,Taiyuan 030001,China)

机构地区：[1]国网山西省电力公司,山西太原030001 [2]国网山西省电力公司晋中供电公司,山西晋中030600 [3]国网山西省电力公司电力科学研究院,山西太原030001

出　　处：《绝缘材料》2022年第8期97-103,共7页Insulating Materials

基　　金：国网山西省电力公司科技项目资助(5205K0200JX)。

摘　　要：为了研究低压电缆局部缺陷定位方法,本文采用频域反射法(FDR)对含缺陷低压电缆进行检测,并对定位结果进行分析。在长度为14.1 m的低压电缆A相、B相及C相依次制作D1、D2、D3三个局部缺陷,其中D1缺陷是在距电缆首端8.7 m处的A相剥掉尺寸为20 mm×2 mm的矩形绝缘(露出缆芯)并联不同阻值电阻模拟高阻及低阻故障,D2缺陷为在距电缆首端4.3 m处的B相制作的长度为5 mm的纵向刀痕缺陷,D3缺陷为在距电缆首端11 m处的C相上制作的V形刀痕缺陷。利用FDR仪对未制作缺陷的A相样本及含缺陷的A、B、C三相样本进行测试。之后将C相样本D3缺陷处浸泡在饱和食盐水中并在电缆首端三相上施加1 kV的电压进行加速老化,老化时间为4周,老化后对样本A、B、C三相进行FDR检测。利用FDR检测结果,分析不同缺陷的频域及时域波形特征。结果表明:无缺陷样本频域波形波峰幅值呈递减趋势,而含缺陷样本缺陷处的波峰幅值增大而且大于两侧波形幅值,且低阻故障时波峰幅值增大更为显著。此外,时域波形上高阻故障表现为一正波,但波峰不显著,而低阻故障表现为一显著的负波。利用FDR频域及时域波形可有效定位低压电缆故障,且对低阻故障定位灵敏度更高。To investigate the partial defects positioning method of low voltage cable, frequency domain reflectometry(FDR) was used to test the low voltage cable with defects, and the positioning results were analyzed in this paper. Three partial defects of D1, D2, and D3 were made successively in phases A, B, and C of 14.1 m long low voltage cable. The D1 defect was a 20 mm × 2 mm of rectangular insulation(expose cable core) in phase A made at 8.7 m away from the head-end of cable and was paralleled resistors with different resistance to simulate high and low resistance faults. The D2 defect was a longitudinal knife mark defect with 5 mm of length in phase B made at 4.3 m away from the front end of cable, while D3 defect was a V-shaped knife mark defect in phase C made at 11 m away from the head-end of cable. The A phase samples without defects and A, B, and C three phase samples with defects were tested by FDR instrument. Then, the D3 defect was immersed in saturated salt water and the three phases end of cable was applied 1 kV voltage for accelerated ageing. The ageing time was four weeks.After ageing, the three phases A, B, and C were detected by FDR. The waveform characteristics in frequency domain and time domain of different defects were analyzed according to FDR detection results. The results show that the peak amplitude in frequency domain of the sample without defect decreases, but the peak amplitude at the defect of the sample with defects increases and is larger than the waveform amplitude on both sides, and the peak amplitude increases more significantly when there is a low resistance fault. In addition, the time domain waveform of high resistance fault shows a positive wave, but the peak is not significant. The low resistance fault presents a significant negative wave. FDR waveforms in frequency domain and time domain can be used to locate low voltage cable faults effectively, and have higher sensitivity to locate low resistance fault.

关 键 词：变电站 低压电缆 局部缺陷 定位 FDR 高/低阻故障 

分 类 号：TM247[一般工业技术—材料科学与工程]