可用于实际工程的MMC-HVDC输电系统等值模型

模块化多电平换流器高压直流MMC-HVDC(modularmultilevelconverterhigh-voltagedirect-current)输电系统中大量的桥臂子模块给仿真带来巨大的计算量,使得仿真速度慢,仿真规模受限。本文通过分析MMC-HVDC系统不同运行条件下的桥臂子模块运行特性,将三种运行工况下桥臂子模块的等值模型进行统一表达,设计出可仿真启动、正常运行和闭锁等多工况的改进的MMC-HVDC系统等值模型。以21电平详细模型与等值模型为例,测试了模型多运行工况性能和模型的仿真速度与精度,并以501电平MMC-HVDC系统测试了模型仿真规模。结果表明所建立的等值模型仿真精度高,仿真规模大,可有效用于工程实际MMC-HVDC系统仿真。

Equivalent Model of MMC-HVDC Transmission System for Real Projects

The large number of arm sub-modules(SMs)in a modular multilevel converter high-voltage direct-current (MMC-HVDC)transmission system may bring tremendous computing workload to the simulation,resulting in slow sim. ulation speed and limited simulation scale. In this paper,the operating characteristics of arm SMs in different operating conditions of MMC-HVDC are analyzed;the equivalent models of arm SMs under three operating conditions are ex. pressed uniformly,and the improved equivalent model of MMC-HVDC that can simulate different operating conditions (e.g. the starting process,normal operation,and blocking state)is designed. With a 21-level detailed model and the equivalent model taken as examples,the simulation speed and accuracy of the proposed model,as well as the model’s performance under different working operating conditions,are tested;in addition,the simulation scale of the model is tested on a 501-level MMC-HVDC system. Results show that the established equivalent model has high accuracy and a large simulation scale,which can be effectively applied to simulate the MMC-HVDC system in real projects.