An Instantaneous Power Quantities Measurement Method Based on Wavelet Packet Transform

With the extensive use of power switching devices, the voltage and current signals become nonstationary. Meanwhile, the interaction between power networks and renewable generations causes sub and/or interharmonics in the voltage and current signals. This paper proposes a method to realize precision measurement of instantaneous power quantities in case of nonstationary signals with sub and/or interharmonics existing. A set of new scaling filter and wavelet filter which have narrower transition band is designed, and the new measurement method based on wavelet packet transform is proposed. Simulation tests validate the well performance of the new method.