Research On The Distribution Characteristics And Laws Of Geo-magnetically Induced Current In Power Grid And Earth

The geo-electric field induced by magnetic storm will produce geo-magnetically induced current (GIC) in power grid and earth. GIC in power grid is relevant to the grid’s structure and parameter, the earth electrical structure and so on, while GIC in earth is influenced by the magnetic storm’s type and intensity, earth resistivity and other factors, and studying the characteristics and laws of GIC in power grid and earth is a frontier work. The problem of GIC in power grid has been researched in large quantities, and the researches are mainly focused on ground electric field calculation, power grid GIC modeling and calculation or effect of equipments and so on. However, there are little researches on GIC in earth. The mechanism and influence factors of GIC in earth are first analyzed, and GIC magnitude in different depth and distribution characteristics of uniform/layered earth conductivity model based on plane wave method and Maxwell equations are deduced. Then the relationship between earth conductivity and GIC in earth are studied and it proves that there is GIC in deep earth.On the basis of previous researches, the distribution characteristics of GIC in power grid are deeply studied, including the distribution characteristics caused by the structure and parameters of power grid and regional differences of GIC distribution caused by latitude, earth resistivity. In the aspect of latitude, geomagnetic data of15geomagnetic stations is used to analyze the latitude difference of GIC in power grid, and in the aspect of geology, the districts with intensive igneous rock through geological map of our country are analyzed. Then prediction research of GIC in power grid based on regional characteristics is performed and preliminary estimates the risk of different areas. In order to evaluate GIC lever in power grid accurately, a method to model the earth conductivity is proposed. Then through study on distribution characteristics of GIC in power grid and earth, references for estimation and prevention for GIC in power grid are provided.