基于小波变换的微网暂态极性比较保护原理及实现

Principle and realization of micro-grid transient polarity comparison protection based on wavelet transform

微电网具有分布式电源运行灵活多变、并网和孤岛方式故障特征差异大的特点,实现满足速动性和选择性要求的微电网保护是微电网技术难点之一。为了实现快速、准确的故障定位和隔离,文中提出了适应并网和孤岛不同运行方式的微网暂态极性比较保护。在研究采用小波变换Mallat算法实现暂态高频信号逐级抽取方法的基础上,依据暂态信号比较提出了微网暂态极性比较保护原理和算法,并重点对微网暂态极性比较保护装置的实现方案进行了设计,最后采用Matlab软件对微网暂态极性比较保护原理进行了仿真验证。

Micro-grid power system has the characteristics of distributed power operation flexibility and the big fault characteristic difference between grid connection and islanding way. Satisfying the quick acting and selective requirements of micro-grid protection is one of the difficulties in micro-grid technology. In order to realize rapid and accurate fault location and isolation,this paper proposed the micro-grid transient polarity comparison protection adapting to the different operation modes of grid connection and islanding way. Based on the research of realizing the decomposition method step by step of transient high-frequency signal by Mallat algorithm of wavelet transform,the principle and algorithm of micro-grid transient polarity comparison protection is proposed according to transient signal comparison,and the realization scheme of micro-grid transient polarity comparison protection equipment is mainly designed. Finally,MATLAB is used to simulate the analysis to verify the protection scheme.