System Harmonic Impedance Estimation Based on Window Width Optimization and Data Screening
倪俊贤 1史明明 2姜锋 1杜嘉诚1
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作者信息
1. 南京工程学院 电力工程学院,南京 211167
2. 国网江苏省电力有限公司电力科学研究院,南京 211103
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摘要
大量电力电子设备的接入导致电力系统中背景谐波波动增大,进而影响谐波阻抗估计的准确性.针对这一问题,该文提出一种基于窗宽优化与数据筛选原理的系统谐波阻抗估计方法.首先,在相关系数数据中引入标准差的指标动态调整窗宽,得到满足筛选样本数量的计算数据,然后利用PCC(point of common coupling)点处谐波电流与系统侧谐波电流呈弱相关的特性筛选出相应数据段,最后引入正则化项进行系统侧谐波阻抗的计算.通过仿真分析和数据计算,将所提出的方法与4种常用方法进行了比较,可以得出当背景谐波波动较大时,该方法可以减少系统谐波阻抗计算的误差,有较高的估计精度.
Abstract
The proliferation of power electronic devices has resulted in an increased occurrence of background har-monic fluctuations in the power system,which in turn affects the accuracy of harmonic impedance estimation.To ad-dress this issue,this paper presents a system harmonic impedance estimation method based on the principles of win-dow width optimization and data screening.Initially,the standard deviation index is introduced into the data to dy-namically adjust the window width,ensuring the selection of calculation data that meets the required number of screening samples.Next,data segments are screened by exploiting the weak correlation between the harmonic currents at the point of common coupling(PCC)and the harmonic currents on the system side.Finally,the regularisation term is introduced for the calculation of the harmonic impedance on the system side.Through simulation analysis and data calculation,the proposed method is compared against four commonly used methods.The findings indicate that the proposed method effectively reduces the error in system harmonic impedance calculation,particularly in scenarios with significant background harmonic fluctuations,thus achieving a high level of estimation accuracy.
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