利用CVT捕捉电压行波实现故障测距的分析与实践

对两次葛岗线单相接地故障实测电容式电压互感器(CVT)二次侧电压数据进行小波分析处理，精确捕捉到初始电压行波波头，并采用双端行渡测距原理准确定位接地故障点，最大绝对误差不超过300m，结合CVT高频等值模型，探讨了CVT二次侧电压测距的可行性。文中还讨论了CVT的频率和暂态特性，重点分析了CVT中间变压器一、二次之间杂散电容对CVT暂态响应的影响，对比实测和仿真波形及其小波变换，说明借助于高速采集的CVT二次电压，能有效捕捉故障初始行波到达时刻，从而实现故障测距的目的。

ANALYSIS AND PRACTICE OF FAULT LOCATION BY VOLTAGE TRAVELING WAVE OF CVT

By using wavelet transformation, this paper introduces the high-speed acquisition of voltage datum of capacitor voltage transformer (CVT) according to two phase-to-ground faults between Ge-Gang transmission line. The process can extract inceptive traveling waves, capture the GPS time stamps and the fault distances by means of the GPS time stamps of two ends. The maximum error of fault location is less than 300 m. Equivalent circuit considering stray capacitance between primary and secondary windings is presented along with the frequency and transient responses of CVT. Comparison results of the practical voltage waves and their wavelet transform with the simulated ones show that the CVT voltage can be used in traveling wave fault location.