Impact load electric energy metering method

Abstract

The invention discloses a method for measuring electric energy of impact load, including the following five aspects: (1) electrical power system produces harmonic and flicker induced by the impact load, electric energy metering of the impact load relates to fundamental wave metering, harmonic electric energy metering and flicker electric energy metering; (2) voltage, current signal of the electrical power system pass through high-pass filter, and perform multi-channel synchronous frequency-change sample by a high-speed ADC(analog / digital converter), realizing harmonic electric energy metering by FFT or wavelet transform, determining harmonic source direction according to positive negative signs of harmonic active power; (3) voltage, current signal of the electrical power system which passing through low-pass filter are performed multi-channel synchronous frequency-change sample by a high-speed ADC, realizing flicker electric energy metering by FFT or wavelet transform, determining flicker source direction according to positive negative signs of harmonic active power; (4) voltage, current signal of the electrical power system which passing through low-pass filter are performed multi-channel synchronous frequency-change sample by a high-speed ADC, abstracting fundamental wave signal by FFT or wavelet transform, realizing fundamental wave electric energy metering; (5) the sampling of high-speed ADC is frequency-change sampling with sampling frequency determined by the fundamental wave frequency.

Description

Technical field [0001] The invention relates to a method for measuring impact load electric energy. The invention belongs to the field of electric power system impact load electric energy measurement. Background technique [0002] At present, the design principles of electric energy metering instruments in power systems are based on the assumption of sinusoidal periodic voltage and current signals, and the theoretical basis is the sinusoidal circuit power theory. With the rapid development of modern science and technology, high-voltage, high-current, and large-capacity impact equipment, such as electric arc furnaces, rolling mills, pulverizers, electric traction machines, etc., have been widely used, and the nonlinear load is increasing. All kinds of pollution are becoming more and more serious, and power quality is deteriorating. At the same time, due to the complex characteristics of such equipment, such as serious power shock, three-phase unbalance, harmonics, flicker, v...

AI Technical Summary

Problems solved by technology

[0005] The disadvantage of the existing technology is that in the power system, the flicker and harmonics caused by the impact load exist at the same time, which affects the accurate measurement of electric energy. If flicker or harmonics are measured separately, there are large errors in the results

[0006] The disadvantage of the existing technology is that in the power system, the voltage and current distortion of the grid lead to the change of the fundamental frequency, and the fixed-frequency sampling of the voltage and current will not be able to track the fundamental frequency, which will affect the accuracy of electric energy measurement.

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