Based on a ±10 kV three-terminal MMC-MVDC (medium voltage DC distribution system based on modular multilevel converter) system, in this study, the authors mainly study on the influencing factors and protection schemes of the lightning intruding overvoltage (including direct lightning and back-flashover lightning). Firstly, a lightning intruding overvoltage simulation model of the MMC-MVDC distribution system using overhead lines is established based on the PSCAD/EMTDC program. The influence of steady-state operating voltage and the number of converter stations on the simulation results are simulated and analysed. Meanwhile, the proper simulation modelling method of the lightning intruding overvoltage for multi-terminal MMC-MVDC system is proposed. Secondly, the lightning intruding overvoltage is simulated when the line is struck by the lightning stroke current that occurs once in 20 years and the different lightning protection schemes are proposed. Finally, based on the lightning impulse withstand voltage, lightning trip-out rate and the cost of the protection schemes, the lightning protection schemes in different scenarios are proposed. The simulation results show that if the cost of the system is prioritised, the protection scheme of increasing the number of parallel stacks of the DL arresters can be selected, and if the power supply reliability of the system is prioritised, the protection scheme of installing the overhead ground wire as well as reducing grounding resistance can be selected.

本文基于±10 kV三端MMC-MVDC（基于模块化多电平转换器的中压直流配电系统）系统，主要研究雷电侵入过电压（包括直接雷电）的影响因素和保护方案。和反向闪络闪电）。首先，基于PSCAD / EMTDC程序，建立了架空线MMC-MVDC配电系统的雷电侵入过电压仿真模型。仿真和分析了稳态工作电压和换流站数量对仿真结果的影响。同时，提出了多端MMC-MVDC系统雷电侵入过电压的正确仿真建模方法。其次，当线路被20年一次的雷击电流击中时，模拟雷电侵入过电压，并提出了不同的防雷方案。最后，根据雷电冲击耐受电压，雷击跳闸率和保护方案的成本，提出了不同场景下的雷电保护方案。仿真结果表明，如果优先考虑系统成本，则可以选择增加DL避雷器并联数量的保护方案；如果优先考虑系统的供电可靠性，则可以选择安装系统的保护方案。可以选择架空地线以及降低接地电阻。最后，根据雷电冲击耐受电压，雷击跳闸率和保护方案的成本，提出了不同场景下的雷电保护方案。仿真结果表明，如果优先考虑系统成本，则可以选择增加DL避雷器并联数量的保护方案；如果优先考虑系统的供电可靠性，则可以选择安装系统的保护方案。可以选择架空地线以及降低接地电阻。最后，根据雷电冲击耐受电压，雷击跳闸率和保护方案的成本，提出了不同场景下的雷电保护方案。仿真结果表明，如果优先考虑系统成本，则可以选择增加DL避雷器并联数量的保护方案；如果优先考虑系统的供电可靠性，则可以选择安装系统的保护方案。可以选择架空地线以及降低接地电阻。