Solar storm heliographic parameters and conditions driving the GIC in grid

The problem of solar storm which caused by solar magnetic field changes effect on power grid is extremely complex physical processes and patterns. Coronal mass ejection (CME) is the main source of the intence geomagnetic storms and geomagnetically induced currents (GIC). To find the CME heliographic parameters related closely to GIC and the parameter conditions which may drive strong GIC in power grid can provide basis for predicting GIC in power grid. We used the GIC data monitored at the Ling'ao nuclear power plant in China and the CME parameters (angular width, initial speed, heliographic position, and acceleration) data observed from SOHO/LASCO to examine their relations and the parameter conditions causing these big GIC events. Our investigation shows that: the GIC value is closely relevant to the CME parameters, among which the CME velocity is the most critical one, but a single parameter cannot independently drive a strong GIC event.