光伏电站经双变换直流并网拓扑及其特性研究

Research on Topology of Photovoltaic Station by Double Transform DC Interconnection and Its Characteristics

为了有效解决光伏电站电能消纳问题,响应构建未来直流电网的趋势,将柔性直流输电系统(Voltage Source Converter-High Voltage Direct Current,VSC-HVDC)与光伏电站结合,本文提出一种大容量光伏电站经双变换直流并网拓扑方案,该方案可以方便对现有DC-AC并网方式的大型光伏电站的改造,文章对该方案的并网特性进行研究,分析VSC的控制策略。基于PSCAD/EMTDC软件,搭建该系统,仿真分析该方案的可行性,表明在光伏电站出力变化时对VSC的有效控制和适当调节无功功率输出可以保持直流电压稳定性,一定程度上提高电网对光伏电站电能的消纳能力。

In order to effectively solve the problem of power given photovoltaic power station, the response to build the future trend of dc grid, the flexible HVDC system （ Voltage Source Converter-High Voltage Direct Current, VSC-HVDC ） combined with photovoltaic power station, puts forward a kind of large capacity photovohaic power station by the double transform dc interconnection topology scheme, this scheme can be convenient to the existing DC-AC interconnection of large photovoltaic power station study of grid feature of the scheme, analysis and control strategy of VSC. The interconnection topology based on PSCAD/EMTDC software, the design scheme, the simulation analysis of the feasibility of the scheme and show that in photovohaic power station output change when the effective control of the VSC and appropriate adjustment of reactive power can be output dc voltage stability, reduce the dc voltage fluctuation, to some extent, improve the ability of power grid of photovoltaic power station power given.