考虑多维应用场景的MMC-MTDC系统拓扑选择和参数配置

针对基于模块化多电平换流器的多端柔性直流 (MMC-MTDC) 输电系统，提出考虑应用场景多维特征的拓扑选择和参数配置方案。根据时间特性、空间分布和资源容量3个维度的场景特征，建立考虑拓扑差异的多端MMC-MTDC输电系统全寿命周期经济性优化模型。提出改进的二阶锥规划(SOCP)松弛方法，将非凸的二次优化转化为SOCP，得出不同应用场景下经济性最优的拓扑结构，制定相应设备出力及线路容量等参数配置方案。参考中国张北柔性直流电网和舟山多端柔性直流输电工程参数，设计对应长、短2种输电距离典型应用场景的四端和五端MMC-MTDC输电系统。从全寿命周期内的总经济效益、新能源消纳率和网损大小3个方面对3种拓扑结构进行经济性分析，验证所提拓扑选型方法的效果。

Topology Selection and Parameter Configuration of MMC-MTDC System Considering Multi-dimension Application Scenarios

Aiming at the modular multilevel converter based multi-terminal flexible direct current (MMC-MTDC) transmission system, this paper proposes a scheme of topology selection and parameter configuration considering the multi-dimension characteristics of application scenarios. An economic optimization model for the whole life cycle of the MMC-MTDC transmission system considering topological differences is established with the scenario characteristics of three dimensions, i.e., temporal characteristic, spatial distribution and resource capacity. The modified second-order cone programming (SOCP) relaxation method is proposed to transform the nonconvex secondary optimization into SOCP. The economically optimal topologies in various application scenarios are obtained, and the configuration scheme of parameters such as the output of relevant equipment and line capacity is formulated. Based on the engineering parameters of Zhangbei flexible DC grid and Zhoushan MTDC transmission in China, this paper designs the four-terminal and five-terminal MMC-MTDC transmission systems in two typical application scenarios with long and short transmission distances. The economic analysis with three topologies is carried out from three aspects, i.e., total economic benefit, the consumption rate of renewable energy, and network loss in the whole life cycle. The effectiveness of the proposed topology selection method is validated.