计及间谐波的重分组小波包变换功率电能测算新方法  

New Power and Electric Energy Measurement Algorithm in Consideration of Interharmonics Based on Regrouped Wavelet Packet Transform

作　　者：尉怡青 赵伟[1] 陈垒[1] 黄松岭[1] YU Yiqing;ZHAO Wei;CHEN Lei;HUANG Songling(State Key Lab of Control and Simulation of Power Systems and Generation Equipment(Tsinghua University),Haidian District,Beijing 100084,China)

机构地区：[1]电力系统及发电设备控制和仿真国家重点实验室(清华大学),北京市海淀区100084

出　　处：《中国电机工程学报》2020年第22期7480-7489,共10页Proceedings of the CSEE

基　　金：国家863高技术基金项目(2015AA050404)。

摘　　要：电网非稳态的电压、电流信号中,若还存在间谐波成分,则以传统算法测算电能和功率,会因不可避免地产生频谱泄漏、频率混叠等,难以实现高准确度的测算。该文提出一种基于IEC61000-4-7频带分组思想的小波包变换(wavelet packet transform,WPT)分组方法,同时利用上单边带调制(upper-sideband modulation,USBM)实现对电压、电流信号频谱的移动,进而利用小波包分解系数计算电压和电流有效值、有功电能以及各功率相关电学量。在此基础上,提出一种在电压、电流信号非稳态且含有间谐波情况下适于测算电能和功率的新算法。仿真试验验证结果表明,该测算新方法在被测电压、电流信号中含有间谐波且存在幅值瞬变或不同程度频率瞬变情况下,均具有较高的测算准确度,且比短时傅里叶变换(short-time Fourier transform,STFT)算法更为稳定。In nonstationary systems with interharmonics, the application of traditional algorithms can cause problems such as spectrum leakage and frequency aliasing, so that it is difficult to achieve high precision electric energy and power measurement. In this paper, a wavelet packet transform(WPT) decomposition method based on frequency-band grouping of IEC 61000-4-7 was proposed. At the same time, the frequency shifting of voltage and current signals was realized by using upper-sideband modulation(USBM). The formulas of the rms values of voltage and current, active energy and power quantities were constructed by using wavelet packet decomposition coefficients. Thereby a high precision electric energy and power metering algorithm in the nonstationary case where interharmonics exist was obtained. The simulation results show that the new algorithm performs higher accuracy in amplitude transients and different frequency transients with interharmonics, and shows strong robustness compared with the short-time Fourier transform(STFT) algorithm.

关 键 词：非稳态信号 间谐波 频带分组 小波包变换 上单边带调制 

分 类 号：TM933[电气工程—电力电子与电力传动]