基于纳秒窄脉冲与时间反演的电缆故障定位系统设计

Design of fault location system for distribution network cables based on narrow pulse generator and time reversal method

配网电缆一般埋于地下,故障定位难度较大。现有基于脉冲信号注入的行波法,由于脉冲幅值较低,在线路上衰减严重,无法有效定位信号微弱的高阻类故障,因此,提出一种基于高压纳秒窄脉冲和时间反演的电缆故障定位方法。通过设计窄脉冲发生器,产生具有纳秒级上升沿和脉宽的高压脉冲,注入到故障电缆中并测量时域反射波形,然后将波形数据进行时间反演后输入到等效仿真模型中,根据时间反演在故障点的时空同步聚焦特性确定故障位置。基于该方法,设计了电缆故障定位软硬件系统。结果显示,该系统能有效实现配网电缆的开路、短路、低阻、高阻等故障定位,且抗噪能力强,可有效满足配网电缆的故障检测需求。

It is hard to locate the faults of distribution cables which are buried underground.In the current travelling wave method based on the pulsed signals injection,it is very difficult to effectively locate the high-resistance faults with weak signals because the pulse amplitude is too low to resist decaying along the lines.This paper proposes a cable faults location method based on high-voltage narrow pulse generator and time reversal method.The narrow pulse generator is designed to generate high-voltage pulse with nanosecond wave front and width,which is injected into the cables and the corresponding reflection waves are measured.The waves are then timely reversed and put into the simulation model.The cable faults are located according to the time-space synchronous focusing characteristics of the time inversion at the fault points.Based on this method,the cable fault location system with hardware and software are designed accordingly.The results show that this system can effectively realize the fault location of open circuit,short circuit,low resistance,and high resistance in distribution cables,which also has strong ability of anti-noise and can effectively meet the fault detection requirements of distribution cables.