电力电缆局部放电的高频与特高频联合检测

摘要

In order to carry out an on-line partial discharge detection for the after-laying power cables and suppress interference occurring in the on-site measurement, the combination method with HF(High Fre quency) and UHF (Ultra Frequency) measurement is proposed, and the on-line partial discharge detec tion system for power cables is established. The system consists of HF and UHF sensor, signal condition ing units, date-acquisition units and PC software, and the impulse interference was removed through mu tual identification between the HF and UHF signal. Meanwhile the interference suppression algorithm of multi-cycle superimposition based on complex wavelet was put forward. The test results for defect cable show that the system can effectively detect the HF and UHF signals of partial discharge with the sensitivity lower than 10 pc, and the processing results for measured data show that the proposed method can sup press the interference well.%为了对已敷设的电力电缆进行局部放电在线检测,并抑制现场测量时的干扰,采用高频(HF)与特高频(UHF)联合检测的方法,建立一套局部放电在线检测系统.该系统主要由HF和UHF传感器、信号调理单元、数据采集系统和上位机软件组成,通过HF信号和UHF信号的相互鉴别来去除脉冲型干扰信号.同时根据干扰信号和局部放电信号在频带及工频相位上的分布特点,提出基于复小波的多周期叠加干扰抑制算法.对缺陷电缆的试验结果表明,该系统能有效检测到局部放电的HF信号和UHF信号,局部放电检测灵敏度小于10 pc;对局部放电采集数据的处理结果表明,所提出的干扰抑制策略可很好地消除测量时的干扰信号.