GIC due to storm sudden commencement in low-latitude high-voltage power network in China: Observation and simulation

Abstract

The impact of geomagnetically induced currents (GICs) on the power networks at middle and low latitudes has attracted attention in recent years with the increase of large-scale power networks. In this study, we report the GIC monitored at two low-latitude 500 kV substations of China during the large storm of 17 March 2015. The GIC due to the storm sudden commencement (SSC) was much higher than that during the storm main phase. This phenomenon is more likely to happen at low-latitude locations, highlighting the importance of SSC in inducing GIC in low-latitude power networks. Furthermore, we ran a global MHD model to simulate the GIC during this SSC event by using the solar wind observation as input. The model results reproduced the main features of the GIC. The study also indicated that the eastward component of the geoelectric field is dominant for low-latitude locations during the SSC events. Further, topology and electrical parameters of the power grids make significant differences in the GIC levels.