基于电子式电压互感器的行波测距技术

为解决行波测距装置在数字化变电站实际应用中存在的问题,分析了电子式电压互感器的暂态行波信号传变特性.通过分析EVT模拟等值电路建立其传递函数,利用仿真模型分析EVT的频率特性,考察电子式电压互感器的一、二次电压行波的相似程度,优化EVT参数使其更适用于行波保护,并讨论不同采样电阻对行波测距精度的影响.结果表明:一定参数下的EVT能够满足行波保护的信号传变要求,EVT的采样电阻取值对行波测距精度影响较大,采样电阻越大,单端测距的误差越大.

Traveling wave fault location technology based on electronic voltage transformer

In order to solve the problem in the practical application of traveling wave fault location device for digital substation, the transient traveling wave signal transmission characteristics of electronic voltage transformer （EVT） were analyzed. Through analyzing the simulation equivalent circuit of EVT, the transfer function was established. In addition, the frequency characteristics of EVT were analyzed with a simulation model, and the similarity between primary and secondary voltage traveling wave signals of EVT was investigated. The parameters for EVT were optimized to make the EVT more suitable for traveling wave protection, and the influence of different sampling resistances on the fault location accuracy of traveling wave was discussed. The results show that EVT can satisfy the requirements in the signal transmission of traveling wave protection under certain parameters. The sampling resistance values of EVT have great influence on the accuracy of traveling wave fault location. Furthermore, the bigger the sampling resistance is, the larger the error of single end fault locating is.