基于反射系数谱的XLPE电缆水树缺陷定位方法  

Location of water tree in XLPE cable based on reflection coefficient spectrum

作　　者：周湶[1] 王鑫源 欧阳希 姜茜 ZHOU Quan;WANG Xin-yuan;OUYANG Xi;JIANG Qian(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China)

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室,重庆大学,重庆400044

出　　处：《电工电能新技术》2021年第7期28-39,共12页Advanced Technology of Electrical Engineering and Energy

基　　金：“111”引智极地国际合作项目(B08036)。

摘　　要：地下电缆中的水树能够在不改变电缆性能的情况下持续生长数年,并最终导致无法预料的绝缘故障。为解决现有技术对电缆水树缺陷定位诊断时存在的不足,提出基于反射系数谱的水树定位方法。首先利用传输线理论构建了含水树缺陷的电缆反射系数谱的解析模型。然后以分布电容为对象分析了水树缺陷对反射系数谱的影响,并基于广义正交法构建了诊断函数D(x)对水树缺陷定位及评估。接着通过仿真实验研究了多因素对诊断结果的影响,优选出了最佳测试频段,分析了诊断灵敏度。最后在实验室对一根50 m且含有2处人工水树缺陷的电缆进行诊断试验。仿真及试验结果验证了方法的有效性和准确性,该方法能够精确定位电缆中多处水树缺陷,定位误差小于0.4%,同时D(x)峰值能够作为水树老化状态评估的新特征量。Water trees in underground cables can continue to grow for years without changing cable performance and eventually lead to unexpected insulation failures.In order to solve the shortcomings of the existing technology in the localization and diagnosis of cable water tree defects,a water tree location method based on reflection coefficient spectrum is proposed.Firstly,the analytical model of reflection coefficient spectrum of cable with water tree defect is constructed by transmission line theory.Then,the influence of water tree defect on reflection coefficient spectrum is analyzed,and the diagnosis function D(x)is constructed based on the generalized orthogonal method to locate and assess the water tree.Then,the influence of multiple factors on the diagnosis results are analyzed by simulation experiments,the best test frequency range is selected,and the diagnosis sensitivity is analyzed.Finally,a 50 m long cable with two artificial water tree defects was tested in the laboratory.The simulation and experiment results verify the effectiveness and accuracy of proposed method.The method can precisely locate multiple water tree de-fects in the cable,and the relative error is less than 0.4%.Besides,peak value of D(x)can be used as new char-acteristic quantity for water tree assessment.

关 键 词：水树定位 反射系数谱 XLPE电缆 分布参数 

分 类 号：TM726[电气工程—电力系统及自动化]