海上风电场将朝深远海、集群化方向发展，鉴于交流电缆在远距离输电时的缺点，有必要对海上风电场集群多端柔性直流输电(voltage source converter based multi-terminal direct currtent, VSC-MTDC)组网优化进行研究。考虑到风电场集群出力的聚集效应会影响电气设备的容量配置，以及陆上电网的公共连接点(point of common coupling, PCC)电压稳定性对大规模风电接入容量的影响。该文推导了PCC点电压稳定性指标，并引入了“N+”原则对电气设备进行容量配置，提出一种计及“N+”原则和PCC点电压稳定性的海上风电场集群VSC-MTDC组网优化方法。采用改进的NSGAⅡ算法对海上风电场集群VSC-MTDC系统进行分析。算例结果表明，按“N+”原则进行容量配置可以更好提高收益，考虑PCC点电压稳定性虽然会增加投资成本，但能够提高PCC点电压稳定性。
英文摘要:
The offshore wind farms will toward into the deep sea and clustering direction. In view of the shortcomings of AC cables in long-distance power transmission, it is necessary to research the optimization method of VSC-MTDC network of offshore wind farm cluster. Considering that the aggregation effect of wind farms cluster will affect the capacity of electrical equipment and the influence of the voltage stability of PCC on the capacity of the integrating wind power. This paper derived a PCC voltage stability index, introduced the concept of "N+" criterion to configure the capacity of electrical equipment, and proposed an optimization method of VSC-MTDC network of offshore wind farms cluster considering voltage stability constraints and "N+" criterion. The improved NSGAⅡ algorithm is used to analyze the the offshore wind farms cluster. The results show that the "N+" criterion had the best economic efficiency, and the PCC voltage stability constraint could increase the investment, but improve the voltage stability of the PCC.