Study On Characteristics Of Transformers Un-der The Influence Of Geomagnetically Induced Currents

Modern age is merely dependent on continuous&uninterrupted electricity supply, where Power transformers as a part of electrical transmission&distribution networks play a vital role; But, there are multiple and un-avoided factors that can disturb the performance of transformers.Geo-magnetically Induced Currents (GICs) produced because of the alleged distur-bances in the Earth’s Magnetic field due to solar cyclic processes; GICs are quasi-dc currents in nature, varying very slowly, with the majority of the spectral content typically less than0.01Hz. The magnitude of GIC is related to the magnitude of the induced voltage, resistances of the line, transformer and earth ground. These Quasi-dc currents when enter in the power systems through neutral points of the Grounded Transformers they cause severe&fatal effects like equipment damage (Transformers, Generators, capacitor banks) and even blackout of the whole Power system network. The network systems of AC/DC convertors of high voltage direct current (HVDC)&the geo-magnetically induced cur-rents (GICs) are the main sources of such Quasi-DC currents.The presence of the quasi-dc GICs in the transformer windings drives the magnetic cores of transformers into saturation during alternate half-cycles, called half-cycle satura-tion. This saturation disturbs the whole operation of cores of power transformers. Mainly, It causes asymmetry&increased amplitude of magnetizing current for only half a cycle, which results in large magnitude of harmonic currents flowing into power systems, greatly increases reactive power consumption in power transformers&other protective problems arise that will be analyzed and studied using Simulations on MATLAB/PSCAD/EMTP simulation soft-wares.