一种改进的Flat-top窗电力系统谐波分析算法  

An improved algorithm for harmonic analysis of power system based on the Flat-top window

作　　者：严晓丹[1,2] 王军[1] 方春恩[1] 曹林[1] 

机构地区：[1]西华大学电气信息学院,四川成都610039 [2]四川省电力公司技术技能培训中心,四川成都710072

出　　处：《电力系统保护与控制》2012年第8期49-56,共8页Power System Protection and Control

基　　金：四川省重点学科(电力电子与电力传动)基金资助(SZD0503-09-0);西华大学重点实验室基金资助(XZD0819-09);西华大学研究生创新基金资助(ycjj201170);科技部国际交流基金

摘　　要：快速傅里叶变换(Fast Fourier Transform,FFT)是电力系统的谐波分析最常用、最容易实现的方法。但由于实际电网频率波动,FFT算法很难实现同步采样,谐波分析精度受到频谱泄漏与栅栏效应的制约。分析了Flat-top窗的旁瓣特性,建立了一种改进的加Flat-top窗FFT算法。通过分段校正方法,当频率偏移量小时,使用计算量小的加Flat-top窗FFT算法;当频率偏移量大时,利用相位差校正法对幅值进行插值修正。仿真结果表明:改进的Flat-top窗相位差校正法有效地抑制频谱泄漏和栅栏效应,提高了电力系统谐波参数的计算精度。The fast Fourier transformation （FFT） is a very popular and the easiest realization way for harmonics analysis in power system. However, it is difficult for FFT to achieve synchronous sampling due to fluctuations of power frequency. The accuracy of the dynamic state harmonic analysis is constrained by the spectral leakage and picket fence effect. As a result, the sidelobe characteristics of the Flat-top window are firstly analyzed, and an improved FFT approach based on Flat-top window is proposed in this paper. Through using sub-correction method, the Flat-top window FFT with small computation is adopted when the frequency offset is small Then, the phase difference correction is adopted to rectify the amplitude of harmonic components when the frequency offset is large. Simulation results indicate that spectral leakage and picket-fence effects are effectively suppressed by using the proposed method, and the precision of harmonic parameters is greatly improved.

关 键 词：谐波 快速傅里叶变换 非同步采样 Flat-top窗 频率偏移量 

分 类 号：TM711[电气工程—电力系统及自动化]