摘要
长距离大容量的高压电缆采用金属护层交叉互联的方式来抵消金属护层中的感应电压,金属护层的交叉互联给在线监测和诊断带来了新的挑战和契机。为此,提出了基于护层电流分析的高压电缆故障在线监测和诊断方法,为高压电缆线路常发生的外力破坏和接地箱进水等问题提前预警。首先,建立了交叉互联电缆系统的护层电流等值电路模型;然后,对交叉互联电缆系统中3个典型的护层故障进行了仿真。通过在某电缆隧道中安装的在线监测装置收集了2015-01—2016-01实测数据,对比仿真结果误差不超过5%,验证了模型的正确性。另外,仿真结果表明故障情况下高压交叉互联电缆护层电流与正常情况下对比有很大差异,且不同故障情况之间对比护层电流也不尽相同。基于以上研究,通过仿真结果建立了不同类型和位置几种典型电缆故障的诊断阈值。因此,根据各电缆接头处所测量的护层电流之间的大小比较可以对不同类型的故障和位置进行诊断。
Cross-linked metal sheath connection is usually applied in long-distance high-capacity power cables to reduce or eliminate the induced voltages in the cable sheath. The cross-linked cable systems present an opportunity as well as a challenge for on-line measurement and diagnosis of cable conditions. Consequently, we put forward a methodology to identify cable faults through monitoring and analyzing the sheath system currents in a cross-linked cable system. Firstly, a numerical model is established to simulate the sheath currents in cross-bonded cable systems. Secondly, three typical kinds of faults, such as the theft of earthing conductors, water ingress to cable link boxes and breakdown of cable joint components, are analyzed, which happen frequently with serious consequences on the basis of current measurement at the link cable. Detailed simulations of normal operating condition and a selected fault conditions are given to determine the feasibility of proposed fault diagnosis method. A case study using field data from a cable tunnel considering the normal condition is adopted to verify the model. Results in normal condition from 2015-01 to 2016-01 show good consistency with field data with error less than 5%. From the analysis results, a set of criteria can be established with which typical cable fault type and localization diagnosis can be made in the future based on the monitoring of cable sheath currents.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2016年第11期3616-3625,共10页
High Voltage Engineering
关键词
高压电缆
金属护层
交叉互联
在线监测
护层电流
故障诊断
I-IV cables
metal sheath
cross-bonded
on-line monitoring
sheath currents
fault diagnosis
