Analysis And Calculation Of The Electric Field Induced By Magnetic Storm Based On Finite Element Method

When a magnetic storm happens, the magnetosphere-ionosphere space current system will generate intense geomagnetic change. As the earth is conductive, the earth’s magnetic field’s change will induce earth surface potential (ESP), when two transformer neutral points are grounded, the ESP would be an equivalent load voltage source between two transformers’neutral points, and this will produce geomagnetically induced curent (GIC) in the grid, which will bring a lot of harm to the grid. This thesis will delve into the changes in the earth’s magnetic field and the electric field when the storm occurs, this will be significant for the study of current in the power grid induced by magnetic storms.Based on the overview of magnetic field’s factors and geomagnetic storm’s morphology and properties, the thesis analyses several major factors that have an impact on GIC. The calculation of ESP is the critical part for the calculation of GIC, so the paper explains the simplified model of the current source of space system in the calculation, as well as earth ground conductivity and construction of conductive structural models, which are the basis when calculating ESP.When analyzing the changes of the electric and geomagnetic field caused by magnetic storms, the the Finite Element method (FEM) is introduced into the analysis and calculation. Two-dimensional and three-dimensional modeling methods are used in the same ground conductivity structure, and the results were compared to verify the feasibility of FEM in three-dimensional models. On this basis, the thesis analyses the electromagnetic field distribution when considering the lateral and longitudinal changes of ground conductivity, it also analyses the "coastal effect" when a magnetic storm occurres and the influence of inclination on that. The Bohai Bay area is chosen as an example, the distribution of ground magnetic and electric fields in the region are analyzed when the magnetic storm occurs. The result provides basis for the calculation of GIC in the network.