基于DB小波变换的多频时变电压闪变检测仿真研究

电压波动与闪变是评价电力系统电压质量的重要参数,因此电压闪变的检测分析对于电力系统的运维至关重要。为了验证Daubechis(DB)小波变换在电压闪变检测方面的有效性与可行性,采用MATLAB搭建了电压闪变信号模型,采用DB小波变换对多频时变电压闪变信号的检测进行了仿真分析,并将仿真结果与基于平方检测法的仿真结果进行了比较。结果表明,DB小波变换不仅能够检测出电压闪变分量的幅值与频率信息,而且能够根据小波变换的模极大值确定电压闪变发生与结束的时刻,而基于平方检测法的电压闪变信号检测无法直接分离出多个电压闪变分量,也无法检测出电压闪变的起止时刻。仿真结果验证了DB小波变换用于电压闪变检测的有效性与可行性。

Simulation Study on Detection of Multi-frequency and Time-varying Voltage Flicker Based on DB-Wavelet Transform

Voltage fluctuation and flicker are important parameters to evaluate voltage quality of power system, so the detection and analysis of voltage flicker is very important for the operation and maintenance of power system. In order to verify the effectiveness and feasibility of Daubechis(DB) wavelet transform in the detection of voltage flicker, this paper established a model of voltage flicker signal with MATLAB. The DB wavelet transform was used to conduct simulation analysis on the detection of multi-frequency and time-varying voltage flicker signal, and the simulation results were compared with the simulation results based on square detection method. The simulation results showed that the DB wavelet transform can not only detect information on the amplitude and frequency of voltage flicker component but also can determine the starting and ending time of voltage flicker according to the modulus maxima of wavelet transform. The voltage flicker signal detection based on square detection method cannot isolate multiple voltage flicker components directly, and it cannot detect the starting and ending time of the voltage flicker. The simulation results showed that the DB wavelet transform is effective and feasible to detect voltage flicker.