基于能量重心法和动态加窗谐波分析法介损计算

Dielectric loss calculation based on harmonic analysis method of energy centrobaric method and dynamic window

在实际应用中,谐波分析法由于受到频谱泄漏和栅栏效应的影响往往会产生很大误差。为了减小谐波分析法的计算误差,提高测量精度,同时考虑处理器的运算能力。提出了一种适用于谐波分析法的介损高精度估算算法。该算法首先对信号进行加Hanning窗的FFT变换后,然后采用能量重心法进行校正。同时使用动态加窗算法对介损角进行了进一步修正,该算法是通过跟随电网的频率波动而动态调节加窗长度,从而使采样更接近整周期采样。经过理论推导和仿真计算,并与其它的改进谐波法进行对比,表明该方法较之前的算法的精度进一步提高,且计算量小,易于工程实际应用。

In the practical application,the harmonic analysis method is affected by the spectrum leakage problem and the occurrence of the picket fence,which causes great errors. In order to reduce the calculation error of harmonic analysis method,and improve the precision of measurement,as well as consider processor computing ability,this paper puts forward a suitable algorithm for high accuracy estimation to calculate the dielectric loss angle of harmonic analysis method. Firstly,the algorithm of FFT transforms with Hanning window to signal,and then we use the energy centrobaric method for correction. At the same time,the dynamic window algorithm is used to modify dielectric loss angle further. The algorithm dynamically adjusts the window length following the frequency fluctuation of power grid,so that the sampling is more close to the full period sampling. Through theoretical derivation and simulation calculation,comparing with other improved harmonic analysis methods,the results prove that the accuracy of this method is further improved than before,and the amount of calculation is small,and easy for engineering application.