Reconstruction Of Power Quality Signals Based On Compressed Sensing

With the rapid development of science and technology,the rapid popularization of power equipment,the number of sensitive components and precision instruments connected to the power grid gradually increases,and the requirements of production and life on the quality of electricity consumption have reached an unprecedented height.At the same time,the use of large-scale rectifier equipment and the increase of power grid coverage make all kinds of power quality problems increasingly serious.The interference in these power grids will not only affect the normal operation of the power system,but also cause huge economic losses due to equipment damage.Therefore,the construction of high-speed and accurate analysis method has become the current research hotspot.As a new signal analysis method,compressed sensing has the characteristics of high speed and precision,especially it can break the restriction of Nyquist sampling theorem,compress the stored signal with a small number of sampling points,and reduce the burden of algorithm operation.Based on the framework of compressed sensing theory,this paper first introduces four kinds of commonly used measurement matrix,and analyzes their performance through a simple reconstruction success rate test.Then three kinds of classical reconstruction algorithms are introduced: matching pursuits(MP),orthogonal matching pursuit(OMP)and generalized orthogonal orthogonal matching pursuit(GOMP)algorithm.Their advantages and disadvantages are analyzed in detail,and a generalized regularized orthogonal matching pursuit(GROMP)algorithm is proposed for the common defect that they are prone to reconstruction failure due to the lack of secondary selection.The new algorithm increases the selection process of regularization,which not only guarantees the reconstruction accuracy,improves the convergence speed,but also increases the stability of the algorithm.Then the orthogonal matching pursuit algorithm,the generalized orthogonal matching pursuit algorithm and the new algorithm are used to analyze the reconstruction of various power quality signals.Their advantages and disadvantages in six aspects of mean square error,signal-to-noise ratio,energy recovery coefficient,operation time,reconstruction success rate and anti noise ability are compared.The simulation results show that the performance of GROMP algorithm isbetter than the other three algorithms,and it is more suitable for power quality signal analysis.Finally,aiming at the common problem of the lack of anti noise ability of the previous algorithm,a two-step filtering method combining threshold selection and matching degree selection is adopted.In this paper,a stagewise-compressive sampling matching pursuit(St-CoSAMP)algorithm is proposed,and the new algorithm is compared with OMP algorithm,GOMP algorithm and GROMP algorithm by simulation.Simulation results show that St CoSaMP algorithm is much better than the other three,and more suitable for power quality analysis in complex environment.