Measurement Error Quantitative Analysis Of Electronic Watt-hour Meter Under The Harmonic Background

Power system harmonic index is one of the most important parameters of the power quality. With the power electronics technology to vigorously develop and wide application broad application, the number of non-linear loads is much more and more, and result in power system voltage and current waveform distortion. Because most of the measuring instruments are designed in accordance with the power frequency sine wave, therefore cause inaccurate measurement data. Electrical energy metering relates to the economic accounting of the grid, and relates to the economic benefits of power generation, supplier and user. The watt-hour meter is the core electrical energy metering and basic measuring, so its measurement accuracy is directly related to the accuracy of electrical energy metering. Therefore, the depth and systematic study of the impact of harmonics on the watt-hour meter and measurement model has great significance.Firstly, the structure and working principle of electronic watt-hour meter is discussed in this paper. By analyzing the error characteristics and the frequency characteristics of electronic watt-hour meter, this paper proposes that, background harmonic the main causes of the measurement error is on time-multiplier.Secondly, mathematical model of the electronic watt-hour meter measurement error has been founded, by mathematical analysis of the principle of the TDM. Based on that, the simulation model of the electronic watt-hour meter is further founded by Multisim, and verify that built the simulation model result are correct. According to different harmonic index simulation analysis get the simulation waveforms. For the simulation waveform difficult measurement problem, we save the simulation waveform as TXT files, then, use Matlab programming calculation to get specific error value. Fundamental superposition of high harmonic background, qualitative and quantitative analyze the electronic watt-hour meter measurement error and verified by case analysis. The analysis shows that, electronic watt-hour meter measuring error is less affected by the change in frequency, and its frequency characteristic curve is smoother. Direction of the fundamental and harmonic power is directly related to the measurement error of plus or minus. Then, confirmed the electronic watt-hour meter measurement error in the whole energy metering mode is far less than the conclusion of the measurement error in the fundamental energy metering mode.Finally, by the principle of the harmonic energy analysis, the direction of harmonic power is determined, and verifying the non-linear load is a harmonic source. This paper discuss the current measurement models and their limitations, and propose a new energy metering for power system harmonic problems. Make clear the user’s electricity consumption type, and perfect the countermeasures of harmonic on electrical energy metering. Achieve a reasonable measurement, rewards and punishments, so that users and power departments are subject to good results.