Research On The Time-domain And Regional Charecteristics Of Geoelectric Field Based On Geomagnetic Data

When magnetic storms occur, the geoelectric field induced in the ground, causing the grid GIC problems that affect the safe operation of the power system. Geoelectric field is the source GIC, and its characteristics could provide a data basis for forecasting the hardest hit of the magnetic storm and selecting monitoring points in the power grid, but also help to assess the level of GIC. This paper studies the time-domain and regional characteristics of the geoelectric field induced during geomagnetic storms, the main contents are as follows:(1) Charecteristics of geoelectric fields induced by different types of storms is studied. Geoelectric fields perform different in different kinds of storms. This paper discovered causes of two kinds of storms and theoretical analyzed the corresponding geoelectric field in time-domain.Then,we got the type of storm that cause the greater impact to grid and predicted the disaster stage of storms.(2) The regional characteristics of geoelectric field based on latitude variation during geomagnetic storms is analyzed. Using geomagnetic data collected from geomagnetic stations distributed all over the country, the paper calculated the geomagnetic fields under 4 typical storms and analyzed the variation characteristics of geoelectric field. Then, possibilities of GIC problem occurrence in transmission lines in different directions at different latitude in China are discussed.(3) Effects of geomagnetic disturbance frequency and the earth eletrical structure on geoeletric field level have been analyzed.The geoeletric field level on types of rocks is calculated under the typical geomagnetic storm,that provides the support for the analysis of GIC serious area in power grids.(4)Based on two typical areas of Xinjiang and Jiangsu, the paper calculated and compared electric fields induced in two areas during storms. The conclusion is:the electric field is affected by latitude and earth conductive at the same time. specially for our country, due to the limited influence of latitude, and the complex structure of the earth, earth conductive is the primary factor.