Research On Power Quality Signal Reconstruction Based On Generalized Orthogonal Matching Pursuit

With the ever-increasing scale of power systems and the increasingly complex use of electricity,the issue of power quality is particularly acute.Power quality has become a mainstream in power system research.It directly relates to the safe power supply,economic benefits,and energy conservation and emission reduction of power systems.Therefore,it is particularly important to monitor and analyze power quality in real time.The use of Nyquist sampling theorem to sample and compress power quality data is limited by the sampling frequency,so system needs to collect a large amount of sampling data.This undoubtedly brings great difficulties to the sampling,compression,storage and transmission of data.Compressed Sensing theory breaks conventional sampling frequency limits with a small amount of sampling,combines the sampling and compression of the signal into one,directly perceives the useful information in the signal.Finally,the original signal is accurately reconstructed by an algorithm,which has a unique application prospect in the field of power quality.This paper mainly studies the reconstruction of power quality signals under the compressive sensing theory.The main research contents are divided into two parts: the sparse basis of the power quality signal and the reconstruction algorithm,as follows:(1)In-depth discussion of the theoretical basis of compressed sensing includes sparse basis,measurement matrix,and reconstruction algorithm.According to the definition and standard of power quality,the signals of the research are classified according to the standard,and single and complex disturbance signal models are established in MATLAB.(2)Aiming at the shortcomings of loss of main information and poor performance of reconstruction due to Fourier sparse bases for transient and composite power quality disturbance signals,a method based on discrete wavelet sparse transform is used to perform power quality signal in the framework of compressed sensing.The simulation experiment results show that the reconstruction accuracy of the transient disturbance is obviously improved by this method,which shows that this method is more universal than the Fourier sparse base and meets the basic requirements for power quality reconstruction.(3)The sparseness of partial steady-state signals is larger under the discrete wavelet sparse transform.A power quality signal reconstruction method based on the generalized orthogonal matching pursuit algorithm is proposed.By improving the atom selection mechanism in the iterative process,not only the ability to reconstruct higher sparsity signals is improved,but also the reconstruction effect is improved.The simulation results show that the generalized orthogonal matching pursuit algorithm not only improves the reconstruction performance of the steady state disturbance signal with high sparseness,but also improves the reconstruction performance of transient and composite disturbance signal.In addition,the reconstruction speed of the generalized orthogonal matching pursuit algorithm has significantly improved compared with other greedy algorithms.All of these indicated that this method is suitable for the accurate reconstruction of various power quality disturbance signals and has certain application reference value.