Electric energy metering method under distorted signal condition based on wavelet transform and curve fitting

Abstract

The invention belongs to the electric power system field and discloses an electric energy metering method under a distorted signal condition based on wavelet transform and curve fitting. The method ischaracterized by firstly using wavelet transform to decompose and reconstruct power grid distortion voltage and current signals and acquiring a fundamental wave signal; then, using Fourier series tocarry out curve fitting on a fundamental wave reconstruction signal, and after normalization, acquiring the measured values of a power grid fundamental wave voltage and a current; and finally, subtracting the measured fundamental wave signal from an original signal and acquiring the power grid distortion voltage and current signals, and through the data processing module of an electric energy metering device, accurately calculating the values of a fundamental wave and distortion electric energy.

Description

technical field [0001] The invention belongs to the field of power systems, and relates to a method capable of accurately measuring electric energy consumption under distorted signal conditions. The method is very effective in enhancing the accuracy of electric energy measurement under distorted signal conditions, and has the advantages of small measurement errors and low detection accuracy. The characteristics of wavelet decomposition layer interference. Background technique [0002] In the modern power system, with the high-speed railway and large-scale new energy grid-connected inverters put into operation, the industrial nonlinear load increases rapidly. The input of these nonlinear loads distorts the grid voltage and current signal waveforms, causing the grid signals to contain a large number of high-order harmonics and impact changes, which seriously interfere with the accuracy and fairness of electric energy measurement. [0003] In the current situation where the si...

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Problems solved by technology

However, the detection results of this method are easily affected by the number of wavelet decomposition layers, and the detection error is large with different decomposition layers.

[0008] To sum up, the existing electric energy measurement methods under distorted signal conditions have their own advantages and disadvantages, and cannot effectively solve the problem of accurate electric energy measurement under unsteady distorted signal conditions such as shock signals in practical applications. Therefore, a measurement method is proposed The error is small, and the detection accuracy is not affected by the number of wavelet decomposition layers. At the same time, the measurement method that can meet the needs of transient electric energy measurement under unsteady distortion signals such as shock signals has great theoretical significance and engineering application value.

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