基于系统误差补偿的改进迭代滤波电力谐波分析方法

Improved iterative filtering power harmonic analysis method based on systematic error compensation

快速准确估计谐波参数可为谐波治理提供可靠依据。迭代滤波方法仅通过简单的时域操作,时域移频和迭代滤波,即可实现电力谐波参数的快速估计。然而,受限于滤波器性能,迭代滤波方法不能完全滤除运算过程中的干扰成分而出现系统误差,影响谐波分析准确度。为降低系统误差对谐波测量结果的影响,分析了基于迭代滤波方法的谐波分析过程的系统误差,并根据系统误差特性提出一种基于系统误差补偿的改进迭代滤波方法。所提方法通过对一个周期内的系统误差的降采样求和补偿,提高迭代滤波方法的谐波分析准确度。基于Matlab的仿真结果表明:在相同滤波次数条件下,所提改进方法的谐波分析准确度高于原始方法2~3个数量级。

Fast and accurate harmonic estimation can provide a reliable basis for harmonic suppression.The iterative filtering method(IF)can achieve fast harmonic estimation only through simple time-domain operations,i.e.,frequency shifting and iterative filtering.However,the systematic error of IF caused by the imperfect performance of the low-pass filter is ignored,which affects the accuracy of harmonic analysis.In order to reduce the influence of the systematic error on the harmonic measurement,an improved iterative filtering(IIF)method based on systematic error compensation is proposed according to the characteristics of the systematic error.The proposed method compensates systematic error within a period by down-sampling and summing to improve the accuracy of IF-based harmonic analysis.Simulation results based on Matlab show that,with the same filtering times,the harmonic analysis accuracy of IIF is higher than that of IF by 2 to 3 orders of magnitude.