基于状态仿真平台的高压电缆接地悬浮缺陷模拟试验分析

Simulation Test Analysis of High-voltage Cable Suspended Grounding Defect Based on Status Simulation Platform

对高压电缆金属护层悬浮电压进行简化计算,并针对高压电缆接地悬浮缺陷搭建了状态仿真平台,构建了直接接地箱缺陷及铝护套接地缺陷,在此基础上开展了典型缺陷在不同工况下长时间状态量变化规律的研究。结果表明:运行中110 kV单芯电缆金属护层两端不接地时的悬浮电压理论计算值可达4.64 k V(外护层良好接地)或57.81 kV(外护层非良好接地);直接接地箱缺陷及铝护套接地缺陷下金属护层接触电压会异常升高,且随试验电压成比例上升;不同试验电流下缺陷段电缆的接地电流和接触电压无明显变化,温升不明显;铝护套接地不良形成较小气隙时,高频电流传感器可检测出明显局放信号,且局放信号强度随试验电压升高而增大。

The suspended voltage of high-voltage cable metal sheath was simplified calculated,and a status simulation platform was built aiming at high-voltage cable suspended grounding defect.Direct grounding box defect and aluminum sheath grounding defect were constructed,and the state quantity change law of typical defects in a long time was studied under different working conditions.The results show that when the both ends of 110 kV single-core cable metal sheath are not grounding,the suspended voltage theoretical calculating value is 4.64 kV(outer sheath well grounding)or 57.81 kV(outer sheath not well grounding).Under direct grounding box defect and aluminum sheath grounding defect,the contact voltage of metal sheath rises abnormally and increases proportionally with the increase of test voltage.Under different test currents,the grounding current and the contact voltage of the defect segment cable change little,and the temperature rise is not obvious.When the aluminum sheath is poor grounding and small air gap is formed,the high frequency current transformer can detect obvious discharge signal,and the intensity of signal increases with the increase of test voltage.