Aiming at the problem that detection of stationary and transient harmonics is easily disturbed by noise,a harmonic detection method for power system based on fractional wavelet transform(FRWT)is proposed.First,the frequency of each spectrum is detected by fast Fourier transform(FFT),and the decomposition level is determined according to the frequency.Then,FRWT is used to decompose and reconstruct the signal,and the fundamental wave and each harmonic component in the signal are separated.Finally,Hilbert transform(HT)is performed on each harmonic component to obtain the frequency and amplitude detection results of each component and the start-end time of transient disturbance.The simulation results of various harmonic signals show that FRWT method can effectively detect the steady-state and transient harmonics in noisy signals and the detection accuracy of each result can be guaranteed even if the signal-to-noise ratio is low.It is proved that FRWT method is an effective new method to detect harmonics.
关键词
分数阶小波变换/小波变换/Hilbert变换/谐波检测/仿真试验
Key words
fractional wavelet transform/wavelet transform/Hilberttransform/harmonic detection/simulation test
维普
万方数据