摘要
远海风电场凭借其丰富稳定的风能资源成为未来风电发展的主要趋势。目前已投运的远海风电送出工程大多采用柔性直流输电技术,其投资成本较高。为此,提出一种基于二极管不控整流单元(diode rectifierunit,DRU)的远海风电低频交流送出方案。该方案取消了海上换流器平台,采用DRU代替常规交–直–交变频器中的低频侧换流器,能够有效降低工程的投资成本和运行损耗。由于DRU不具备主动控制能力,提出适用于远海风电低频交流送出系统的风电机组控制策略,其中机侧换流器采用定直流电压控制,网侧换流器则在全局统一参考坐标系下同时实现最大功率跟踪控制和交流侧电压控制。最后,通过PSCAD/EMTDC进行算例仿真,对风电功率波动、陆上交流电网三相短路故障和海上交流电网三相短路故障等典型工况下的系统响应特性进行研究,验证所提方案的可行性。
The offshore wind power,which is high in density and small in fluctuation,will be the focus for wind power development in the future.Up to now,the offshore wind power transmission projects in operation have mostly adopted VSC-HVDC technology,whereas their capital cost is relatively high.So,this paper proposes a diode uncontrolled unit(DRU)based low frequency alternative current(LFAC)transmission scheme for the offshore wind farms,in which the offshore platform of the rectifier is cancelled and the rectifier in the traditional AC-DC-AC frequency converter is substituted by the DRU,thus significantly reducing the project investment and operating cost.Since the DRU is uncontrolled,a corresponding control strategy of the offshore wind turbines is proposed for LFAC transmission system,in which the machine side converter(MSC)controls the DC voltage and the grid side converter(GSC)implements the maximum power point tracking(MPPT)and AC voltage control together in the global unified reference coordinate system.Case simulations in PSCAD/EMTDC were carried out in the end to study the system response to typical operating conditions including wind power fluctuation and three-phase faults in the onshore grid and offshore grid,and the feasibility of the proposed scheme is verified.
作者
唐英杰
张哲任
徐政
TANG Yingjie;ZHANG Zheren;XU Zheng(College of Electric Engineering,Zhejiang University,Hangzhou 310027,China)
出处
《中国电力》
CSCD
北大核心
2020年第7期44-54,168,共12页
Electric Power
