Research On Metering System Of Non-linear Loads

The electrical energy is the basis of economic settlement between power grid and plants, power companies and consumers, power grid and power grid, the accuracy and reasonableness of energy measurement related to the economic interest-3of both sides. With the rapid development of modern industry, a large number of non-linear loads connect to the grid resulting in that a number of harmonics injected into the grid, which make power quality drop, the power users abnormally work, and the same time seriously affect the electricity measurement. Therefore, the study of measurement devices of non-linear load provides the basis to punish harmonic source users,which has theoretical and practical value.This paper discusses the status of electric power measurement in the case of harmonic, analyses comprehensively the effect of harmonics on the induction meter and electrical meter. The necessity of harmonic power measurement and the measurement method of non-linear load is elaborated in detail, on the basis of which, the harmonic analysis algorithm is focused on, and FFT algorithm used to bring the effects of spectral leakage and fence effect, the application of window function is discussed. This paper puts forward the harmonic method based on Hanning-windowed interpolated FFT algorithm, makes the simulation experiment in MATLAB to verify the correctness of the algorithm.On the basis of theoretical analysis, directing at the measurement of nonlinear loads in the electric power industry, this paper presents a nonlinear load measurement system design, the system uses AD+dual CPU scheme, signal acquisition unit adopts AD company’s AD73360, TI’s TMS320F206is choosed and STM32F103RBT6based on CortexTM-M332-bit RISC core is selected as a management control CPU. The study analyses the working principle and function of the system, and focus on the hardware circuit design, including signal acquisition circuit, DSP data processing circuit, MCU management control circuit, power circuit, communication circuit, etc. Integrated hardware design, software design adopts modular programming ideas, which makes the architecture of system clear and concise, the software implementation process of the data acquisition and processing module is analyzed detailly.The power metering system of non-linear load in this paper can realize the nonlinear load harmonic analysis and accurate measurement of electric power, has the extendibility,can facilitate the system hardware and software update, has the very good application value.