Mitigation of flux produced by geomagnetically induced currents (GIC) on power transformers with delta windings

Geomagnetically induced currents (GIC) arise in our power system due to fluctuationsin the earths magnetic field, which commonly is caused by space weather events. Thesecurrents may result in core saturation for transformers that get exposed. The purposeof this project is to clarify the possibility of reconnecting the delta connected tertiarywindings in order to mitigate the saturation that is caused due to GIC. Laboratorystudies were performed on different types of transformers, which later were simulated andcompared to the experimental results, in order to verify the credibility of the simulations.This will allow us to trust the results of the simulations performed on a large transformerto a greater extent.Geomagnetically induced currents (GIC) arise inour power system due to fluctuations in the Earths magneticfield, which commonly is caused by space weather events. Thesecurrents may result in core saturation of transformers that getexposed. The purpose of this project is to clarify the possibilityof reconnecting the delta connected tertiary windings in orderto mitigate the saturation that is caused by GIC. Laboratorystudies were performed on different types of transformers, whichlater were simulated and compared to the experimental results,in order to verify the credibility of the simulations. The studyconcludes that partial DC flux mitigation can be very effectivein order to prevent core saturation as a result of GIC