说明：  多端直流输电系统(multi-terminal DC，MTDC)为解决 大型风电基地功率外送的瓶颈问题提供了一个最佳解决方 案。研究了基于电压源换流器(voltage source converter，VSC) 的多端直流输电系统应用于大规模风电功率长距离外送时 的协调控制策略。通过构建一个四端系统连接两个大型风电 基地及本地电网向远方负荷中心进行功率输送，实现了风电 场的功率汇集和外送。仿真验证了该协调控制策略在大扰动 情况下，不仅能够提高VSC-MTDC系统潮流重新分配的能 力，而且可使风电场对直流网络提供一定功率支撑，增强了 电力系统动态稳定性
(Multi-terminal DC (MTDC) power transmission system is regarded as the optimal solution scheme to sent out power from large-scale wind farm. A coordinated control strategy for voltage source converter (VSC) based MTDC transmission system applied to long-distance power transmission from large-scale wind farm is researched. By means of constructing a four-terminal system connecting two large-scale wind power bases with local power grid to send out power to faraway load center, the wind power converging and sending out by the proposed coordinated control strategy are implemented. Simulation results show that the proposed coordinated control strategy not only can improve the ability of reallocating power flow in VSC-MTDC transmission system under large disturbance, but also can make wind power base providing a certain power support to DC transmission network, thus the dynamic stability of power grid can be enhanced. )