Modeling and Risk Assessment of Geomagnetically Induced Currents During Geomagnetic Storm in the 500 kV Power Grid of Guangxi, China

Geomagnetic storms can induce geomagnetically induced currents (GIC) in power systems, posing threats to grid security. In this study, a GIC calculation model for the 500 kV power grid in Guangxi, China, is developed based on one‐dimensional (1D) and various three‐dimensional (3D) magnetotelluric (MT) impedance data. The geomagnetic disturbance data of the “solar superstorm” on July 23–24, 2012, were simulated using the Space Weather Modeling Framework. Together with five real geomagnetic storm events, these data were used to estimate the GIC responses at each substation. The results show that the substation GIC peak calculated using the simulated geomagnetic disturbance data in July 2012 is as high as 243 A, which is comparable to the GIC peak calculated during the geomagnetic storm from October 29 to 31, 2003. Some substations experienced GIC exceeding 300 A during the geomagnetic storm on May 10–13, 2024. When the geomagnetic storm intensity reaches the level of the October 29–31, 2003 event, the differences in GIC estimates between 1D and 3D MT impedance data can be as large as 300 A. When storm intensity reaches the level of the May 10–13, 2024 event, the differences in GIC estimates derived from different 3D MT impedance data can be as much as 100 A. The GIC risk assessment identified six high‐risk substations, all located in southeastern Guangxi. Among them, three coastal substations are recommended for prioritized deployment of GIC monitoring devices.