基于Db小波变换的直流系统的研究

直流系统的可靠性和安全性对于发电站、变电所的各种负载装置的正常运行有重要的影响,与电网的安全生产息息相关。低频信号注入法作为常用的直流系统接地故障检测方法之一,容易受到对地电容的影响而影响检测的准确性,针对这一问题,深入分析低频信号注入法的原理及存在问题,提出在低频信号注入法的基础上,用小波变换原理,选取适当的小波函数,对提取的信号进行分析和处理。仿真结果表明,该方法可以有效消除对地电容对直流检测的影响,为实现接地故障点的准确定位奠定基础。

The Detection of DC System Based on Db Wavelet Analysis

The reliability and security of DC system have a significant impact on normal operation of various load devices in power stations and substations. It is also closely to production safety grid. As one of the detection methods in DC system grounding fault, the low frequency signal injection is easily influenced by the capacitance to ground and influence the accuracy of detection. According to this problem, deeply analysis the method, principle and existing problems of low frequency signal injection, put forward in the low frequency signal injection method based on wavelet transform, selecting the suitable wavelet function, and then extract and process the signal. The simulation result shows that the method can overcome the influence of the capacitance to ground and in order to locate in grounding fault accurately.