An algorithm for reduction of extracted power from photovoltaic strings in grid-tied photovoltaic power plants during voltage sags
An algorithm for reduction of extracted power from photovoltaic strings in grid-tied photovoltaic power plants during voltage sags
复制标题
电压暂降期间并网光伏电站光伏组串提取功率减少算法
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
V. Agelidis
中科院分区：
文献类型：
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作者：
H. D. Tafti;A. I. Maswood;J. Pou;G. Konstantinou;V. Agelidis
由于已安装的分布式发电机组在电力系统中的高渗透率，中大型并网光伏电站（PVPPs）需要注入无功功率。由于并网逆变器的电流限制，在电压暂降期间注入的有功功率应该减少。为了在多串PVPP中获得恒定的直流链路电压，在所有操作条件下（不包括功率损耗），从PV串提取的功率应该等于注入到电网的功率。因此，在电压骤降期间，PV串的提取功率应该减少。在本文中，提出了一种算法，用于确定光伏串的参考电压，这导致输出功率减少到一定量。所提出的算法计算的DC/DC转换器控制器的参考电压，基于PV串的功率-电压曲线的特性，因此，在DC/DC转换器的控制器中不需要修改。对一个50 kW的光伏串的仿真结果验证了该算法在不同辐照和参考功率值下降低光伏串功率的有效性。
Due to the high penetration of the installed distributed generation units in the power system, the injection of reactive power is required for the medium-scale and large-scale grid-connected photovoltaic power plants (PVPPs). Because of the current limitation of the grid-connected inverter, the injected active power should be reduced during voltage sags. In order to obtain a constant dc-link voltage in a multi-string PVPP, the extracted power from PV strings should be equal to the injected power to the grid in all operating conditions (excluding power losses). Therefore, the extracted power of PV strings should be reduced during voltage sags. In this paper, an algorithm is proposed for determining the reference voltage of the PV string which results in a reduction of the output power to a certain amount. The proposed algorithm calculates the reference voltage for the dc/dc converter controller, based on the characteristics of the power-voltage curve of the PV string and therefore, no modification is required in the the controller of the dc/dc converter. Simulation results on a 50-kW PV string verified the effectiveness of the proposed algorithm in reducing the power from PV strings under different irradiation and reference power values.