Lifting wavelet scheme and wavelet energy entropy theory for transient power quality detection

Wavelet entropy (WE), which is calculated from the lifting wavelet transform (LWT) coefficients, is proposed to detect and locate power quality disturbances. As one of methods to build second-generation wavelets, LWT can be easy to achieve in time domain for its original bit location calculation and could lessen calculation complexity due to its particular structure, compared with first generation wavelet transform (WT) algorithm. As shown by the simulation experiment results, the proposed WE measurement scheme based on LWT approach has been validated efficient comparing with classical WT algorithm through various test scenarios, including oscillatory transients, voltage sag, and voltage swell, momentary interruption.