基于小波变换的谐波电流监测及线损分析

针对谐波电流带来的电网损耗问题，提出了利用小波变换和FFT进行谐波电流检测及电网损耗分析的综合监测方法。基于小波变换的多分辨率分析方法，对电网电流谐波进行了检测，并将基波信号和谐波信号分离，利用傅里叶变换方法，得到低频部分中稳态谐波的频谱信息；根据各谐波分量的幅值，计算电网电流畸变率、功率因数以及造成的线路功率损耗，实现对谐波电流的监测。结果表明，随着低频谐波电流幅值的减小，电流畸变以及造成的功率损耗将会明显降低；随着电流谐波成分的增加，将会导致电网功率损耗增加。该研究为电力系统电能质量监测以及谐波治理提供了理论基础。

Harmonic current monitoring and line loss analysis based on wavelet transform

In view of the power loss problems caused by harmonic current, a comprehensive monitoring method of combining Fourier transform and wavelet transform is proposed to detect the harmonic current and analyze the power loss. The power system harmonic current is detected by the way of the wavelet multi-resolution analysis method; and the fundamental current is separated from the total harmonic current. The spectrum of low frequency harmonics in the steady-stage is obtained by Fourier transform analysis. The current distortion rate, power factor and line loss are calculated according to the amplitude of each harmonic to realize monitoring of harmonic current. The simulation results show current distortion rate and line loss will decrease with the decrease of low frequency harmonics amplitude; the line loss will increase with the increase of harmonic current content. The research results can provide a theoretical foundation for power quality monitoring and harmonic management in power system.