The Power Harmonic Measurement And Iimplementation Based On Wavelet Packet Algorithm Using FPGA

With the development of modern industry, a large number of non-linear loads in thepower system increases. These non-linear loads absorb the non-sinusoidal current from thegrid, resulting the distortion of the grid voltage, and the power qualities are seriouslydeteriorated, which endanger the safe and economic operation of power systems and affect theuser’s normal work. Harmonic content has become an important parameter to measure thepower quality supply system and the harmonic detection is of great significance.This paper introduces the basic concepts of power system harmonics, harmonic hazards,the harmonic source and harmonic measurement method and its shortcomings, and exploresthe continuous wavelet transform, discrete wavelet transform and wavelet packet transform,wavelet theory, and analysis the frequency characteristic of these types of wavelet transformand compare with the Fourier transform, study of the wavelet packet analysis and waveletpacket decomposition coefficient reconstruction in-depth. As for the lack of Fourier transformfor power system harmonic analysis, the paper introduces the harmonic analysis andmeasurement methods that based on FPGA using wavelet packet decomposition coefficientsreconstruction algorithm. Stationary signal and non-stationary signal experiment based on theMATLAB platform prove the feasibility and accuracy of this new approach; explore the use ofwavelet transform to decompose a signal into a band, determine frequency range of theharmonic content of the analysis contained in the band according to the sampling frequencyand wavelet packet decomposition scale, and get all integer and non integer harmonic value inthe band to overcome the spectral leakage of traditional harmonic measurements, the barriereffect caused by missing information to improve measurement reliability and accuracy.Highlights the power harmonics measurement based on wavelet packet algorithm andFPGA implementation, the results of the laboratory source proved that, the FPGA-basedpower system harmonic parameter measurement system has better data processing functions,higher precision, with actual use value.