Modified Wavelet Threshold Method In Signal Noise Reduction Of Power Line Communication

With the rapid development of power grid,artificial intelligence,big data platform and intelligent Internet of Things technology have been put into the construction of smart grid.Information acquisition system,as the main body of distribution automation system and the foundation of smart grid system,is the carrier of power grid information digitization.However,due to the complex topology of low-voltage distribution network and a wide variety of electrical equipment,it is difficult to avoid the interference of various noises in the transmission of information in the carrier channel,and sometimes the communication reliability will be seriously affected.Therefore,it is necessary to research a power line carrier communication denoising method to strip the data disturbed by noise.This article first expounds the basic principle of low voltage power line carrier channel,and analyzes the general characteristics of the noise in the power line channel and distinctive features of all kinds of noise,noise source,according to the frequency spectrum characteristics will noise is divided into two major categories of background noise and impulse noise,at the same time,combining with the characteristics of all kinds of noise for the mathematical modeling and simulation.Aiming at the complex noise interference of low voltage power line carrier channel,a noise reduction method based on improved wavelet threshold method is proposed.Firstly,the classical wavelet denoising algorithm is simply analyzed,the specific flow of wavelet denoising algorithm is clarified,the wavelet threshold value of adaptive decomposition scale is selected,and the threshold function is improved to improve the noise removal rate of noisy signal.On the basis of wavelet threshold function,the classical modal theory is studied,and a denoising method of power line carrier signal based on variational modal decomposition combined with wavelet threshold function is proposed.After removing the IMF component stripping of noise,the wavelet threshold denoising algorithm is applied to the IMF component containing noise to further filter the noise component.The two signal processing algorithms proposed in this paper can effectively denoise the carrier signal,especially the power line carrier communication channel denoising method combined with variational mode decomposition and wavelet threshold de-noising method,which can keep the smoothness of the signal well on the basis of removing the extensive background noise.