Calculation of power system harmonics via wavelet packet decomposition in real time metering

The fast Fourier transform is used widely in harmonic analysis for real time power metering due to its low computational complexity. An alternate method, wavelet packet decomposition, has been applied to power system signals to meter voltage and current harmonics Although the new method provides better analysis, the computational complexity of commonly used filters such as Daubechies, Vaidyanathan, and Beylkin places a limitation on its use in real time metering. This paper proposes an all-pass implementation of Butterworth IIR filters to reduce the computational complexity of the aforementioned FIR filters while providing similar if not better magnitude characteristics.