Research On The Effect Factors Of Geomagnetic Induced Current In Mid-low Latitude Power Grid

Geomagnetically induced currents (GIC) in power grids caused by magnetic storms, it’s values are affected by many factors, such as magnetic storm type, electrical structure of the earth and topology of power grids. Analysing and researching the influence factors of GIC in power grids have great help for the evaluation of GIC level in grids and the grids security protection. This article from the regional difference of magnetic disturbance intensity, the earth conductivity and power grid structure studied the influence of different factors on the low latitude grid GIC, the main contents are as follows:(1) The geomagnetic data interpolation method based on equivalent current ionospheric inversion is proposed. The geomagnetic data of any place can be acquired by the interpolation method from a limite number of geomagnetic observation data. The interpolation data is used in the grid GIC calculation and analyses the influence on grid GIC by the geomagnetic data differences. Compared with the measured data to verify the reliablity and accuracy of this method.(2) Geomagnetic disturbance frequency and the earth electrical structure effect on geomagnetic storm induced geo-electric field level have been analyzed. The geo-electric field level on types of rocks is calculated under the typical geomagnetic storm, that provides the support for the analysis of power grids GIC serious area.(3) The values of GIC in Guangdong500kV grid under uniform geo-electric fied and typical storm have been calcuated. The effect of line length, direction and corner effect which belong to topology of power grids have analyzed through the GIC results calculated in grid and the GIC sensitive nodes are identified.