Calculation of geomagnetically induced currents reactive power loss disturbance in China’s UHV power grid considering the influence of 500 kV power grid

Abstract

Geomagnetically induced currents (GIC) in power systems which are generated during magnetic storms, increased reactive power consumption in transformers, it is necessary for geomagnetic storms disaster prevention in power system to calculate GIC-Q increment and recognize voltage changes of substation nodes under simultaneity and proruption of massive GIC-Q loss disturbance in whole power grid. A method combines U - I curve and transformers’ reactive loss coefficient parameter K is proposed to calculate transformers’ GIC-Q increment, based on the GIC data of 1000 kV UHV power network in China, and considering the influence of 500 kV transformers’ GIC-Q loss on 1000 kV power grid, we used the Newton method to calculate voltage fluctuation of 1000 and 500 kV power grid under GIC-Q disturbance. At last, the impact of the simultaneity of massive GIC-Q loss on the 1000 and 500 kV grid is analyzed, we investigated the mutual influence between these two power grids under all circumstances. The results show that 1000 kV Fuzhou substation has a maximum voltage fluctuation that drops by 74.48 kV, whose voltage deviation compared with normal shows a decrease of 7.13%, which beyonds the regulation that the operating voltage deviation should not exceed ±5%. And whether the suddenly voltage drop of 74.48 kV can lead to the reduction of SVC devices reactive power output, and the simultaneity of massive GIC-Q loss as well as the suddenly reduction effect of SVC reactive power output need to be further researched.