考虑系统侧谐波电压波动的光伏接入点谐波发射水平评估方法  

A Method for Assessing Harmonic Emission Level of Photovoltaic Access Point Considering System-Side Harmonic Voltage Fluctuations

作　　者：张旭 徐永海 刘子腾 蒋海玮 陶顺 ZHANG Xu;XU Yonghai;LIU Ziteng;JIANG Haiwei;TAO Shun(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Source,North China Electric Power University,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206

出　　处：《中国电力》2021年第3期109-116,共8页Electric Power

基　　金：国家自然科学基金资助项目(51777066)。

摘　　要：随着光伏逆变器的广泛应用,其运行时产生的谐波与接入点系统背景谐波叠加,引起谐波放大甚至谐振问题,评估光伏接入点谐波电压发射水平对于防范谐波问题具有重要意义。与传统的非线性负荷不同,光伏逆变器经过滤波器滤波后接入电网,公共连接点(PCC)的光伏侧谐波阻抗可能不满足传统电网中远大于系统侧谐波阻抗的条件。同时,电力电子设备的不断接入导致系统产生了大量谐波,谐波电压波动逐渐增大。因此,首先根据光伏逆变器、滤波器以及线路谐波阻抗的参数,估算光伏侧谐波阻抗;然后基于逻辑斯蒂回归(LR)对公共连接点的谐波电压、谐波电流数据对进行分类,筛选出系统侧谐波电压基本一致的数据对组,进而通过偏最小二乘法估算系统侧谐波阻抗,减小系统侧谐波电压波动的影响;最后,基于光伏侧和系统侧谐波阻抗的估算,对光伏接入点的谐波电压发射水平进行评估。通过与其他方法仿真对比分析,验证了所提方法的先进性和准确性。With the extensive application of photovoltaic inverter,the harmonic generated during its operation overlaps with the background harmonic of the system at the access point,which causes harmonic amplification and even resonance problems.It is therefore of great significance for the prevention of harmonic problems to evaluate the harmonic voltage emission level of the access point.Different from the traditional non-linear load,the photovoltaic inverter is connected to the power grid after being filtered by filter,which may cause the PV-side harmonic impedance at the point of common coupling(PCC)not to meet the condition of the traditional power grid that requires the PV-side harmonic impedance to be much greater than the system-side harmonic impedance.At the same time,the continuous access of power electronic equipment leads to a large number of harmonics in the system,and the fluctuation of harmonic voltage increases gradually.Therefore,according to the parameters of photovoltaic inverters and filters and the harmonic impedances of the lines,the photovoltaic-side harmonic impedance is estimated firstly.Secondly,the harmonic voltage and harmonic current data of the PCC are classified according to the logistic regression,and the data sets with basically identical background harmonic voltages are selected.And then the system-side harmonic impedance is estimated using partial least square method,so as to reduce the influence of system-side harmonic voltage fluctuation.Lastly,based on the estimation of photovoltaicside and system-side harmonic impedance,the harmonic voltage emission level is evaluated.Compared with other methods,the proposed method is proved to be superior and accurate.

关 键 词：光伏 谐波阻抗 谐波电压 谐波发射水平 逻辑斯蒂回归 

分 类 号：TM464[电气工程—电器]