基于双层阻抗模型的三相单芯电缆自恢复故障定位  

Fault Location of Self-Clearing Fault in Three Phase Single Core Cables Based on Double Impedance Model

作　　者：张姝[1] 林圣[1] 唐进[1] 何正友[1] 

机构地区：[1]西南交通大学电气工程学院,成都610031

出　　处：《电工技术学报》2016年第17期1-10,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51307145);四川省应用基础计划(2014JY0177)资助项目

摘　　要：地下电缆的失效过程伴随着周期性发生的自恢复故障。快速准确地定位这类故障能够在电缆发生永久性击穿之前发现电缆潜在故障位置,为电缆的运维检修提供依据。计及电缆金属护层的影响,提出一种基于双层阻抗模型的三相单芯电缆自恢复故障定位方法。推导了双层阻抗模型下,三相单芯电缆导芯-护套自恢复接地故障和导芯-护套自恢复短路故障下的故障回路方程。利用电缆首端监测的电流电压波形,在较短故障时间下得到故障位置信息,最后通过最小二乘回归法实现了三相单芯电缆自恢复故障定位。大量仿真表明,计及电缆护套行为的故障定位算法能够准确识别电缆自恢复故障位置。该算法相对于只考虑导芯阻抗的算法更符合电缆实际模型,能够反映三相单芯金属护层的电气行为。The failure process of the underground cable also accompanies the periodical self-clearing faults. Fast and accurate location of this kind of fault can find the potential fault points before a permanent breakdown,which provides the basis for operation and maintenance of underground cables. An algorithm for locating the self-clearing fault based the double impedance model in the three phase single core cables has been proposed that considers the impact of the metal sheath. The circuit equations of the core-sheath-ground self-clearing fault and the core-sheath self-clearing fault have been derived based on the double impedance model. The proposed method uses the time-domain information of the current and voltage waveforms monitored in the headend of cables. The self-clearing fault can be located by the least squares regress method during a short time. Extensive simulations show that the algorithm, considering the behavior of the metal sheath of cables, can locate the self-clearing fault accurately. The proposed method is more consistent with actual structure of cables than the methods only consider the impedance of the core and it can explain the electri-cal behavior between the conduction and metal sheath of coaxial cables.

关 键 词：单芯电缆 金属护套 自恢复故障 双层阻抗 故障定位 

分 类 号：TM77[电气工程—电力系统及自动化]