基于线芯-护层过渡电阻无功特性的交叉互联电缆故障测距  

Fault Location of Cross-Connected Cables Based on Reactive Power Characteristics of Core-Sheath Transition Resistance

作　　者：杨明嘉 夏成军[1,2] 赖胜杰 池梓斌 Yang Mingjia;Xia Chengjun;Lai Shengjie;Chi Zibin(School of Electric Power South China University of Technology,Guangzhou 510640 China;Guangdong Province'New Energy Power System Intelligent Operation and Control Enterprise Key Laboratory,Guangzhou 510663 China)

机构地区：[1]华南理工大学电力学院,广州510640 [2]广东省新能源电力系统智能运行与控制企业重点实验室,广州510663

出　　处：《电工技术学报》2024年第5期1372-1389,共18页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划项目(2022YFB2403500);南方电网公司科技项目(031300KK52200003)资助。

摘　　要：高压电缆常见的接地方式是交叉互联接地,而交叉互联接地电缆故障时的测距相比单端接地或两端直接接地的电缆情况更为复杂,为此提出了基于线芯-护层过渡电阻无功特性的交叉互联电缆故障测距方法。首先,采集护层故障前后环流,构建不同电缆区段特征电流,判断故障发生区段;其次,考虑电缆金属护层对线芯的耦合作用和线路电容影响,建立交叉互联电缆的故障稳态等效阻抗模型,利用电缆首末两端线芯和护层的电压、电流推算电缆故障发生时不同区段沿线电压、电流,并基于同一位置电压相量对电缆参数进行修正;然后,利用故障点过渡电阻消耗无功功率为零的功率特性建立以故障距离为未知数的测距方程,采用二分法或弦截法等方法迭代计算求解得到故障点;最后,基于PSCAD/EMTDC仿真软件搭建了电缆故障模型,分析了故障距离、故障类型、过渡电阻、故障初相角等因素对故障测距方法的影响。结果表明,该方法的测距误差为0.4%左右,具有较高的准确性和有效性,对交叉互联接地电缆进行故障测距有一定的参考意义。High-voltage power cables are widely used in the construction of urban power grid,but there are often short-circuit faults mainly caused by single-phase faults.Rapid and accurate fault location is of great significance to maintain the stable operation of power grid.The high voltage cable with a length of more than one kilometer usually adopts the cross-connected grounding mode,and the coupling between the cable structure,fault phase and non-fault phase brings great difficulties to fault location.At present,the main fault location methods of cross-connected cables are traveling wave method and impedance method,but the reliability of traveling wave method is low,and the impedance method has shortcomings such as not considering the influence between the three phases and ignoring the line capacitance.Therefore,a fault location method for cross-connected cables is proposed in this paper.Firstly,based on the doubleπmodel,considering the coupling effect of the cable metal sheath on the wire core and the influence of the line capacitance,an equivalent model is established for the single-phase short-circuit fault of the cross-connected grounding cable.Secondly,the voltage and current of cable core and sheath are collected before and after the fault occurs,and the difference integral of sheath circulation before and after the fault is calculated according to the measured current of the cable sheath circulation monitoring point,and the short-circuit fault area is judged by whether the difference integral change is the largest.Then,the cable parameters are modified based on the pre-fault electrical volume,and the voltage and current along the first and end of the fault section are calculated by the post-fault electrical volume.Finally,the fault location equation is constructed based on the zero reactive power consumed by the transition resistance of the fault branch,and the fault distance is obtained by iterative calculation.The simulation results of the proposed method show that by calculating the integral of the differenc

关 键 词：高压电缆 交叉互联 无功特性 故障稳态 故障测距 

分 类 号：TM247[一般工业技术—材料科学与工程]