电工技术学报2024，Vol.39Issue(5)：1372-1389,18.DOI:10.19595/j.cnki.1000-6753.tces.222277
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
摘要
Abstract
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 double π model,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 difference between the measured current at both ends of different sections of cross-connected cable as the characteristic current,the characteristic current value of the fault section is obviously greater than that of the non-fault section,and the fault section can be effectively judged.The method of line parameter correction can modify the inaccurate and changing line parameters within 1.1%,and reduce the electrical parameter error obtained by calculating or measuring the initial conditions of the cable.The fault location equation is established and iterated repeatedly to obtain the location result,which avoids the accident of the calculation result. The simulation results show that the fault distance,fault type,cable arrangement,fault initial phase angle,transition resistance,line parameter change and ground resistance have little influence on the method,and the maximum distance error is less than 0.4%.Compared with the two-layer impedance model,the impedance model based on the line distribution capacitance has better location accuracy,so the line capacitance should not be ignored in the cable fault location.关键词
高压电缆/交叉互联/无功特性/故障稳态/故障测距Key words
High voltage cable/cross connecting/reactive power characteristic/steady state of fault/distance of fault分类
信息技术与安全科学引用本文复制引用
杨明嘉,夏成军,赖胜杰,池梓斌..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[J].电工技术学报,2024,39(5):1372-1389,18.基金项目
国家重点研发计划项目(2022YFB2403500)和南方电网公司科技项目(031300KK52200003)资助. （2022YFB2403500）
