A real-time estimation method of three-phase voltage applied to dynamic energy metering
A three-phase voltage and energy measurement technology, applied in the direction of AC/pulse peak measurement, etc., can solve the problems of poor real-time performance and large amount of calculation, and achieve the effect of improving real-time performance and accuracy, improving measurement accuracy and reducing correction errors.
Active Publication Date: 2019-12-03
GUIZHOU POWER GRID CO LTD
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[0005] The technical problem to be solved by the present invention is to provide a method for real-time estimation of three-phase voltage applied to dynamic electric energy metering, so as to solve the problem of using discrete Fourier transform (DFT) or fast Fourier transform to detect harmonics in the prior art High precision, simple implementation, but large amount of calculation, poor real-time performance and other technical problems
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[0043] A three-phase voltage real-time estimation method applied to dynamic energy measurement, which is characterized in that by collecting three-phase voltage signals at the same time, the instantaneous frequency is calculated on the premise of fewer sampling points, and the instantaneous frequency calculation result is The sequence is reconstructed by way of domain interpolation to realize synchronous sampling, and finally the fundamental wave amplitude of each phase voltage is obtained through the sliding window iterative DFT, so as to realize the real-time measurement of the three-phase voltage, which includes the following steps:
[0044] Step a. Sampling rate f at an integer multiple of the nominal voltage frequency s Collect the three-phase voltage signal and get the discrete sampling sequence, denoted as V A (n), V B (n), V C (n);
[0045] Step b. Take the weight coefficients of the cosine term as 0.52 and 0.48, construct a cosine combined self-convolution window, denoted a...
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The invention discloses a three-phase voltage real-time estimation method applied to dynamic electric energy metering, and the method comprises the steps: collecting a three-phase voltage signal at asampling rate fs which is an integer multiple of the nominal voltage frequency, and obtaining a discrete sampling sequence; constructing a cosine combination auto-convolution window and recording thewindow as w (n), and recording Fourier transform of a window function as W (i); weighting the A-phase voltage initial N-point discrete signal sequence VA (n) by using a window function w (n), and carrying out fast Fourier transform to obtain a sequence VAFFT (i); finding out a peak spectral line and an adjacent spectral line, correcting the spectral line, and solving an accurate frequency fma; calculating the instantaneous frequency f of the subsequent n sampling point according to the characteristics of the three-phase voltage; determining a subsequent time domain interpolation point to reconstruct the sampling sequence according to the calculated accurate frequency fma and the instantaneous frequency f of the nth point; then, completing the calculation of the voltage amplitude parameter; and thus improving the tracking capability and the measurement precision of the dynamic voltage.
Description
Technical field [0001] The invention belongs to dynamic electric energy measurement technology, and particularly relates to a real-time three-phase voltage estimation method applied to dynamic electric energy measurement. Background technique [0002] There are a large number of rectifiers, variable frequency speed regulation devices, electric arc furnaces, electrified railways and various power electronic equipment in the distribution network. The nonlinearity, impact and imbalance of these loads have caused serious pollution to the power quality. With the continuous increase in the capacity of power converters, the rapid increase in the number of applications and the diversification of control methods, the side effects of power electronic devices have become increasingly prominent. The high-order harmonic currents generated by these devices are injected into the power grid in large quantities, which distorts the sinusoidal waveform of the grid voltage, reduces the power quality...
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IPC IPC(8): G01R19/04
CPCG01R19/04
Inventor 张俊玮温和张秋雁欧家祥单铉昇张博古庭赟牛唯安甦吴冕之丁超朱亮唐立军邓高峰孙航王扬王蓝苓胡厚鹏李航锋
Owner GUIZHOU POWER GRID CO LTD