Research On Measurement Method Of Electric Energy Under Power Grid Distortion Signal

In the modern power system,the non sinusoidal and non steady state distortion signals appear because of the nonlinear and impact load.In the case of distortion,the traditional energy meter based on the design of the steady-state sinusoidal signal will erroneously measure the power,so that cause economic losses to the power company and the user.And the distortion signal back to the grid will have an impact on the power quality.Therefore,it is very scientific significance and social value to study reasonable energy measurement methods and design a reasonable measurement device.In this paper,the lifting wavelet transform algorithm is used to analyze and calculate the distortion signal,and the electric energy metering device is designed based on TMS320F28335.Firstly,the typical characteristics of the distortion signal are extracted,and then the classification and abstraction process is simplified.The mathematical model of the signal under the power grid distortion is established.According to the power flow direction analysis theory,the irrationality of the traditional energy measurement method is proved.Secondly,the lifting wavelet transform algorithm is used to analyze and calculate the distorted signal.This paper discusses the method of measuring the energy of wavelet transform,and improves the accuracy of the algorithm by wavelet basis selection.At the same time,the rationality of the algorithm is verified by Matlab simulation based on traditional and non-traditional distorted grid.Finally,the hardware and software design of the electric energy metering device is introduced in detail.In order to ensure the speed and measurement accuracy of the system,this paper chooses TMS320F28335 hardware system,and completes the work of distortion signal processing,data processing of electric energy measurement and liquid crystal display and data acquisition module control.At the same time,the software design,according to the modular theory,the paper completed the main program and the function of the subroutine design in the CCS environment.