Research On High Precision Wideband Phasor Measurement Under Polymorphic Noise

Large-scale wind power/photovoltaic and other renewable energy generation,high-voltage AC/DC power transmission connected to the power grid,so that the power system has a high trend of electronization.The large-scale application of power electronic devices injects a large number of low-frequency and high-frequency components into the power network,thus promoting the wide-frequency characteristics of power network signals.In order to improve the monitoring capability of power electronic network operation,it is necessary to extend the measuring range of synchronous phasor from narrow-band base-frequency component to broad-band component,this paper explores a new generation of electronic panoramic broadband measurement technology based on broadband phasor measurement data.At the same time,the power electronic power system contains noise as well as broadband component.Therefore,this paper studies the low frequency component and high precision phasor measurement of power frequency component of broadband noise under the condition of polymorphic noise.The major findings of the study include:(1)For the measurement of low frequency components,the basic principle and characteristics of the Prony algorithm are explored.The Prony algorithm can identify the noise-free signals accurately,but there is a big error for the noise-free signals,secondly,the basic principle of EEMD and the principle of de-noising are analyzed.Although this algorithm can decompose the noisy signal into a series of IMF,the traditional EEMD de-noising method has the shortcomings of incomplete de-noising and false filtering of useful signals Based on the eemd-robustoica-Prony Algorithm,a high-precision phasor measurement method for low-frequency components is proposed.By using this method,the over-sensitivity of Prony algorithm to noise can be effectively overcome,at the same time,the problem of poor denoising effect of the traditional EEMD denoising method is solved.The Matlab simulation software shows that the EEMD-robustica-prony Algorithm proposed in this paper can remove the noise better and realize the high precision phasor measurement of the low frequency component more accurately.(2)In view of the power frequency component measurement,the shortcomings of traditional power frequency standard algorithms are analyzed,and the advantages and disadvantages of all phase FFT and TLS-ESPRIT Algorithms are introduced systematically,the phase will not change due to the frequency deviation.When the frequency is close,the resolution of all-position FFT is low,but TLS-ESPRIT Algorithm has high resolution to the frequency.It can deal with the problem of frequency close,but the calculation process is very complicated.It can not make the reasonable detection to the phase and the amplitude.In this paper,the advantages of the two algorithms are combined to promote the all-phase FFT-TLS-ESPRIT Synthesis Algorithm,which can guarantee the good detection precision of phase and frequency,reduce the computation load and improve the computation speed.The simulation results show that the FFT-TLS-ESPRIT Algorithm is effective and can achieve high precision phasor measurement for power frequency components.