Statistical Characteristics Of Geomagnetically Induced Currents And Extreme Magnetic Storm Hazards Model In The Power Grid

Geomagnetically Induced Current generated by magnetic storm hazards in the power grid can cause hazards to power equipment and even lead to widespread power outages in severe cases.The study of extreme magnetic storms on power systems requires a large number of statistical samples,and magnetic storms are typically "high impact,low probability" events with very limited direct observations.Therefore,the construction of magnetic storm hazard scenarios with the help of simulation is a necessary part of the study of the mechanism and risk of magnetic storms.The modeling of extreme magnetic storm hazard scenarios is an urgent issue for magnetic storm hazard prevention and control.The specific work of this paper is as follows:(1)A GIC calculation model suitable for large-scale power grids is established.Firstly,based on the ionospheric equivalent current method,the historical observation data of geomagnetic disturbance are interpolated to make up for the deficiency of the observation data;Secondly,the hierarchical and partitioned modeling method of the conductivity of large-scale complex structures is proposed,and the equivalent calculation of induced geoelectric field is carried out.Finally,the equivalent circuit model of GIC suitable for largescale complex power grid is established,and the fast calculation of power grid GIC under the influence of extreme space weather disasters is realized.(2)The influencing factors of GIC are explored,and further conclusions on the important statistical characteristics of GIC probability distribution are drawn.The Dst index is used to screen 20 mega and large magnetic storm events during 2008-2018;based on the geomagnetic observation data of the Meridian Project,the grid GIC time-domain simulation method is applied to calculate the induced ground field and grid GIC of the Sanhua 1000 kV UHV grid,the northwest 750 kV UHV grid and the Guangdong 500 kV UHV grid in China;the calculation results are used as statistical samples,the effects of three major factors,namely magnetic storms,earth and grid,on the grid GIC are clarified;the probability model of Weber distribution of grid GIC is established,and it is proposed that the GIC distribution is dominated by the scale parameter a,and the shape parameter b can be considered as a constant value in the modeling study.(3)A multiple linear regression-based extreme magnetic storm hazard model is constructed.The quantitative indicators of magnetic storm factor,geodetic factor and grid factor are proposed;the regression equations of the Weber distribution scale parameters of grid GIC are obtained based on multiple linear regression with the quantitative indicators of the three factors as explanatory variables;the three indicators are reasonably graded and the typical values are selected according to the needs of the scenarios to obtain the GIC probability distribution of the corresponding scenarios;the extreme magnetic storm disaster scenarios are constructed and the "1-in-100-year" values of grid GIC are further calculated.The GIC probability distribution of the corresponding scenario is obtained by selecting the typical values according to the needs of the scenario.