Geomagnetically induced current uncertainty quantification based on the earth conductivity models constructed by the Kriging method

Abstract

• Proposed and verified the superiority of Kriging method in constructing earth conductivity model. • Illustrate the necessity of uncertainty analysis for GIC. • Obtained the sensitivity of GIC input parameters(transformer parameters, transmission line parameters and ground resistance parameters) in 1000kV UHV Northern China power grid. With the expansion of power grid, the hazard of geomagnetically induced current (GIC) has attracted more attention. Due to the small number of Magnetotelluric detection points, the earth conductivity model based on limited data cannot be adapted to the GIC calculation of large-scale power grids. In addition, it is necessary to consider the effect of simultaneous changes in multiple input variables on GIC calculation results. Therefore, this paper presents a method for modeling the conductivity of the earth which is used in the case of less data, and uses the model to quantify the uncertainty. Based on the existing Magnetotelluric data in Northern China, the conductivity model within the power grid region is established using the Kriging method. The uncertainty quantification model of the GIC is constructed based on the Polynomial Chaos Expansions(PCE) method. The uncertainty quantification analysis is carried out for the 1000 kV ultra-high voltage Northern China Power Grid. The statistical information of the GIC and its sensitivity to each input parameter are obtained.