Power measurement under time-varying waveform using discrete wavelet packet transform

The study provides a new approach based on discrete wavelet packet transform for measurement of power quantities defined in the IEEE 1459 standard. Firstly, this paper gives the concepts f the minimum frequency band width and the corresponding number of decomposition layer. Based on these concepts, the power associated with each harmonic component could be represented by the power quantity within the corresponding frequency band. The proposed algorithm takes fully into consideration the effects of dc offset and the inter-harmonics, so that it is suitable for power measurement under time-varying waveform. The proposed method is verified by two representative cases, and simulation results proved the validity and accuracy of the algorithm.