Analysis of a geomagnetic induced current on a three-phase power transformer and power system

A geomagnetic induced current (GIC), resulting from adverse space weather, has a low occurrence rate but the potential for high impact events. Such events can disrupt the operation of a power system, especially the power transformer as the current flows in the transmission lines and through the transformer ground points. It is a well-documented fact that a GIC can cause a significant threat to ground-based networks as the induced current can enter into the transmission system through the wye-grounded transformers. This paper presents a simulation of a GIC on an IEEE 9-bus test system under steady-state conditions using PSCAD/EMTDC software. The main focus of this paper is the effects of a GIC on a three-phase power transformer that includes half cycle saturation and reactive power consumption. Based on the simulation results under GIC conditions, the magnitude flux and magnetising current of the power transformer as well as reactive power consumption increase and may lead to power system instability. (paper)