The Research Of Algorithm Of Power Quality Disturbance Filtering Based On FRFT

With the large input of electronic equipment and the harm of heavy load,the power quality of the power grid is gradually declining.The problem of power quality is paid more and more attention by all walks of life and various departments and consumers.It is an important premise to improve the power quality by filtering and detecting the disturbance signal correctly.Power quality disturbances are complex and can be divided into two types:steady state and transient state.If only the analysis in time domain or frequency domain is used,it is feasible to analyze a few power quality disturbances.At present,the main method is to analyze and detect the power quality disturbance by means of time frequency joint method.In this paper,the problem of transient power quality disturbance is studied.In order to improve the power quality,we should choose the appropriate measures.Then we can do better filtering,detection,evaluation and classification for various transient problems.According to the nonstationarity of transient power quality,several transient signal filtering methods are described in this paper.The filtering method based on fast Fourier transform(FFT)is one of the most widely used algorithms,but it can only be used to analyze stationary signals.For non-stationary signals,uses the transient power quality disturbance filter based on fractional Fourier transform(Fraction Fourier transform)is used in this paper.Although FRFT has a good effect on transient signal processing,it has the defect that it can not reflect the local characteristics of the signal.But the traditional wavelet has the shortcoming in the time-frequency domain.In order to make up for these shortcomings,a new fractional wavelet transform based on FRFT is proposed.Using MATLAB/Simulink simulation platform to build the model,the output of the FRFT noise signal filtering result is obtained.The experimental results show that the filtering effect of FRFT is better than that of FFT,and proves the validity of the FRFT.The fractional wavelet transform has the advantages of less calculation,good filtering effect,better ability to restore the waveform and its characteristics,and overcomes the shortcomings and deficiencies of the single algorithm.The feasibility of the algorithm is verified.In this paper,the filtering method has good filtering effect for transient signal,and can be used to analyze the transient disturbance signal effectively.