GEOMAGNETIC EFFECTS ON POWER SYSTEM

Geomagnetically Induced Currents (GIC) are caused by solar eruption which emit charged particles into the earth. These change in the magnetic field induce potential gradients in the earth's crust, which in turn case GIC to earth's crust. EHV transmission lines which are solidly grounded y transformers are potentially very good conductors of GIC. GIC which is quasi-continuos, cause unsymmetrical saturation on transformers, thus bring voltage harmonies, unusual VAR consumption, and temperature rise in transformers. The three limb transformers are less prone to GIC induced saturation than five limb or three single phase transformers. In this paper, we describe GIC phenomena, GIC monitoring methods, and power system protection against GIC. We also use the EMTP program for the modelling of GIC