基于小波变换的非线性负载畸变电能计量研究

摘要

With a large amount of impact load connected to the power grid, the low voltage side of the grid signal appears non sinusoidal distortion, which seriously threatens the stable operation of the power grid.Traditional electric energy meter based on the sinusoidal signal measurement, distortion signal will lead to a large number of electricity ignored, which bring economic losses to power grid.Based on the research progress at home and abroad, the mathematical model of electric power signal compo-nents was establish, and the composition of distorted signal was analyzed.Using wavelet transform algorithm, the signal distortion was process to verify the accuracy of the db4 wavelet energy metering method.Research shows that compared with the fast Fourier transform and wavelet transform, db4 promotes the fundamental power of wavelet transform was more close to the theoretical val-ue.%随着大量冲击性载荷接入电网，电网低压侧信号出现非正弦畸变，严重威胁电网稳定运行。传统电能表多基于正弦信号进行计量，畸变信号会导致漏计大量电能，给电网带来经济损失。基于国内外研究进展，建立了电网信号数学模型，分析了畸变信号下功率的组成成分。采用提升小波变换算法对畸变信号进行处理，验证了db4小波电能计量方法的准确性。研究表明：相比较于快速傅里叶变换和第一代小波变换，db4提升小波变换的基波功率值更接近于理论值。