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混合双馈入直流输电系统中电网换相换流器高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)子系统对电压源换流器高压直流输电(voltage source converter based high voltage direct current,VSC-HVDC)子系统运行特性的影响机理有待深入研究.首先建立了基于不同LCC-HVDC子系统控制模式的混合双馈入直流输电系统数学模型,并分析归纳了VSC-HVDC子系统的安全稳定运行约束条件和判据,提出了一种确定混合双馈入直流系统中VSC-HVDC子系统稳态运行区域的计算方法.在此基础上对比分析了VSC-HVDC子系统稳态运行区域与LCC-HVDC子系统控制模式、交流系统短路比、LCC-HVDC与VSC-HVDC容量配比之间的关系.最后,基于PSCAD/EMTDC软件搭建了混合双馈入直流系统仿真模型,仿真验证了VSC-HVDC子系统稳态运行区域计算方法的有效性.“,”The influence mechanism of line commutated converter based high voltage direct current (LCC-HVDC) sub-system to the operation characteristic of voltage source converter based high voltage direct current (VSC-HVDC) sub-system in hybrid dual-infeed HVDC system needs further study.Firstly,the mathematical models of hybrid dual-infeed HVDC system with different LCC-HVDC control modes were derived in this paper.Based on these models,the security and stability constraints of the VSC-HVDC sub-system in hybrid dual-infeed HVDC system were analyzed and summarized.Then,an approach to determine the stable operating area of the VSC-HVDC sub-system in hybrid dual-infeed HVDC system was presented.Based on this method,the impact of the different control mode of LCC-HVDC sub-system,the short circuit ratio (SCR) of AC system and the capacity rate between LCC-HVDC and VSC-HVDC on the stable operating area of VSC-HVDC sub-system were studied.Lastly,the validity of the proposed approach was proved by hybrid dual-infeed HVDC simulation model built in PSCAD/EMTDC.