高压电缆附件局部放电超高频检测与分析

Ultra-high Frequency Detection and Analysis for Partial Discharge in High-voltage Cable Accessories

为保障XLPE电力系统安全运行,开展高压系统附件局部放电(PD)检测研究,建立了110kV交联聚乙烯电缆接头的数学物理模型并利用时域有限差分法对其内部产生的PD超高频(UHF)电磁波的传播特性进行数值仿真。研究检测位置和金属护套以及半导电层等4种因素对UHF信号波形畸变和能量衰减的影响,并通过实验室电缆接头PD实测验证的仿真结果表明:金属护套和半导电层对UHF信号波头和频率有较大的衰减作用,在-20dB衰减条件下,UHF传感器距离接头的理论值应<3m,且上限频率≤500MHz。

The mathematical and physical model of 110 kV XLPE cable joints was established, in which the transmission characteristics of ultra-high frequency （UHF） electromagnetic wave resulted from partial discharge（ PD） was also simulated by FDTD. Four types of influential factors on waveform distortion and energy loss of UHF signals were researched, such as detection position, metal sheathing：, semi-conductive layer, and so on. The simulation results are verified by actual PD measurement of 110 kV cable joints in laboratory, indicating that metal sheathing and semi-conductive layer play an important role in the attenuation on the wave front and frequency of UHF signals. UHF sensors should be limited within 3m from the accessories, and the upper limiting frequency should be lower than 500 MHz under the attenuation situation of -20 dB.