Method for RMS and power measurements based on the wavelet packet transform

The study provides the theoretical basis for the use of the wavelet packet transform (WPT) method for RMS and power/energy measurements. The proposed method can simultaneously measure the distribution of RMS quantities and power with respect to individual frequency bands directly from the wavelet transform coefficients associated with the concurrent voltage-current pair. Their dependent quantities such as power factor and total harmonic band distortion can also be calculated. Uniform frequency bands result from the WPT decomposition of power system waveforms and can be used for identification of bands of harmonics. The frequency bands also retain both the time and frequency relationship of the original waveforms, which is one of the major benefits provided by this method. The method is evaluated by its application to both simulated and actual power system waveforms