地磁扰动会在高压电网中诱发产生地磁感应电流(GIC)，使得电力变压器等发生相继故障，从而导致电力系统崩溃或者引起大停电事故，研究地磁暴条件下电网连锁故障风险评估能够为预防其引起的电网事故提供重要参考。对地磁暴条件下电网连锁故障的机理进行了分析，提出了地磁暴条件下电网连锁故障风险评估流程，该流程可以识别各个地磁暴条件下电网的薄弱环节；利用系统的负荷削减量来评估连锁故障各个阶段对系统的危害，同时利用给定地磁暴条件下该薄弱环节导致电力系统崩溃所削减的临界负荷量来评估其对电力系统的危害。利用IEEE-RTS79系统对于所提出的流程进行验证，验证结果表明所提出流程的可行性和有效性，所得结果可以为量化和防范地磁暴电网风险提供参考。

Geomagnetic disturbances will induce Geomagnetically Induced Current (GIC) in high voltage power grid, which will cause cascading failure in power grid, resulting in power system collapse or blackout. Therefore, research on risk assessment of cascading failure in power grid under geomagnetic storms can provide important reference for preventing accidents caused by geomagnetic storms. This paper analyzes the mechanism of cascading failure under geomagnetic storm conditions and proposes a risk assessment process for cascading failure in power grid under geomagnetic storms. The process can identify the vulnerable links of the power grid under each geomagnetic storm condition, evaluate the risk of the different stages of the vulnerable links by using the load shedding of the power system and use the critical load shedding caused by vulnerable links to evaluate its risk to the power system. Finally, the proposed process is verified by using the IEEE-RTS79 system. The verification results show the feasibility and validity of the proposed process. The results obtained can provide a reference for quantifying and preventing the risk of the power grid under geomagnetic storm conditions.