基于改进协方差特性的永磁直驱风电场谐波发射水平评估  

Assessment Method of D-PMSG Wind Farm Harmonic Emission Level Based on the Improved Covariance Characteristic

作　　者：熊敏 杨洪耕[1] Xiong Min;Yang Honggeng(College of Electrical Engineering Sichuan University Chengdu,610065 China)

机构地区：[1]四川大学电气信息学院

出　　处：《电工技术学报》2020年第3期603-611,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目（51477105,51877141）

摘　　要：风机滤波器在某些谐波频率呈现低阻抗,估计谐波发射水平误差大,因此提出基于改进协方差特性估计永磁直驱风电场谐波发射水平的方法。根据风机滤波器和风电场网络结构,聚合各元件阻抗用于简化永磁直驱风电场侧附加谐波阻抗计算。在此基础上,利用改进协方差特性建立了公共连接点处谐波电压和电流的偏差量与系统侧和风电场侧的谐波阻抗的表达式,得到系统谐波阻抗,进而求出谐波发射水平。该方法克服了公共连接点处谐波电流与背景谐波相关性带来的误差。仿真分析和实测数据计算验证了所提方法的有效性。The wind turbine filter presents low impedances at some harmonic frequencies, the error of harmonic emission level is large. This paper presents a new method to estimate the D-PMSG wind farm harmonic emission level at the point of common coupling(PCC) based on the improved covariance characteristic. According to the wind turbine filter and the wind farm network topology, the impedance of each component is aggregated to simplify the calculation of the D-PMSG wind farm additional harmonic impedance. The expression of the deviation of harmonic voltage and current at the PCC and the harmonic impedances on system side and wind farm side is established by the improved covariance characteristic. Then, the system harmonic impedance and the D-PMSG wind farm harmonic emission level can be calculated. The proposed method avoids the error caused by the correlation between harmonic current at the PCC and background harmonic. I t verifies that the proposed method can effectively eliminate the influence of background harmonic on the results through simulation and practice case.

关 键 词：风力发电 谐波发射水平 谐波阻抗 随机矢量协方差 

分 类 号：TM71[电气工程—电力系统及自动化]