用小波包测量无功功率

Reactive Power Measurement Using Wavelet Packet

介绍用小波包求基于Budeanu定义的无功功率的新算法。小波包可以对小波空间进一步分解,把给定信号分解到更多频段,从而提高频率分辨率,分解到各频段的信号是时域信号,可以求出给定信号在各频段的参数。小波包分解是一种比多分辨率分析更加精细的分解方法,通过小波包分解的信号具有更好的时频特性。将电压、电流和各次谐波分别移90的电压正交小波包分解,用分解系数可求出无功功率,以及电压有效值、电流有效值、有功功率等,还可以求出各子带上的有功功率及无功功率。对算法进行了仿真研究。

A new arithmetic was proposed using wavelet packet to calculate reactive power based on Budeanu＇s definition. Wavelet space can be decomposed further using wavelet packet to increase frequency resolution. A signal can be decomposed in more frequency band by wavelet packet than by multiresolution analysis. These decomposed signals are in time domain and the parameter in each frequency band can be calculated. Wavelet packet decomposition is much finer than multiresolution analysis. These decomposed signals by wavelet packet have better time-frequency localization property than by multiresolution analysis. A voltage signal, a current signal and the voltage signal shifted 90° for each harmonics were decomposed using wavelet packet. RMS of voltage and current, active power and reactive power can be calculated using coefficients, and active power and reactive power in each subband can also be calculated. Simulation using the new arithmetic was carried out.