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视在短路比增加量(apparent increase in short circuit ratio，AISCR)是一种定量评估混合多馈入系统中电压源换流器型高压直流输电(voltage source converter based high voltage direct current，VSC-HVDC)对电网换相换流器高压直流输电(line commutated converter based high voltage direct current，LCC-HVDC)运行特性影响关系的指标，该文基于AISCR指标，定量评估混合双馈入系统中当VSC-HVDC潮流方向不同时对LCC-HVDC运行特性的影响，在此基础上基于PSCAD/EMTDC对比分析VSC分别作为整流运行和逆变运行时LCC-HVDC的暂态过电压、换相失败抵御能力、故障恢复等暂态运行特性。研究当 VSC-HVDC 与LCC-HVDC之间存在电气距离的情况下AISCR随着电气距离的变化趋势；最后将交流系统与 VSC-HVDC 对LCC-HVDC 视在短路比增加量的耦合作用进行了解耦，得到了不考虑VSC-HVDC所联结的交流子系统的影响，仅考虑 VSC-HVDC 单独作用时 AISCR 的变化规律，该结论可以为混合多馈入直流输电系统中VSC-HVDC容量及馈入落点的选取提供理论指导。“,”Apparent increase in short circuit ratio (AISCR) is an index to quantitatively evaluate the impact of voltage source converter based high voltage direct current (VSC-HVDC) on line commutated converter based high voltage direct current (LCC-HVDC) in hybrid mutli-infeed HVDC system. Based on the AISCR index, the impact of VSC-HVDC on LCC-HVDC was further studied considering different power flow direction of VSC-HVDC link. Then, the transient performances of LCC-HVDC, such as transient over-voltage, commutation failure immunity and fault recovery performances, were investigated in PSCAD/EMTDC software, when VSC operates as rectifier or inverter. Considering the electric distance between VSC-HVDC and LCC-HVDC, the trend of AISCR was calculated with varying distance. Finally, the coupling effects of AC system and VSC-HVDC on AISCR of LCC-HVDC were decoupled, and the AISCR impacted by VSC-HVDC only, without the impact of AC system, was obtained. The conclusions got could provide valuable theoretical guide for capacity and feed-in location selection of VSC-HVDC in hybrid multi-infeed HVDC system.