Geomagnetic induced current modelling and analysis on high voltage power system

Abstract

Geomagnetically induced current (GIC) has become a significant concern that can affect the electrical power grid by causing a half-cycle saturation of power transformers. This saturation leads to an increase in even and odd harmonic distortions and reactive power losses of transformers, which may consequence in improperly triggering relays, tripping reactive power (VAR) compensators and shunt capacitor banks. Also, these reactive losses, harmonic, and the stray flux resulted due to this saturation may lead to overheating windings and cores of power transformers and generators and hence blackout. In this paper, GIC analysis has been conducted on a modified IEEE-18 bus test system by using Power System Simulator for Engineering (PSS/E) and Power System Computer-Aided (PSCAD/EMTDC) software. The simulation results have been obtained by considering a worst-case scenario of geomagnetic disturbance (GMD) by applying uniform induced electric fields with values of 10 V/km and 20 V/km at different directions with and without GIC blocking devices. Also, the impact of grounding resistances of the substations on calculated GIC due same mentioned induced fields has been investigated. The results show that the highest total reactive power losses across the system are obtained due to related induced electric fields at 120° and 300° storm angle. After the connection of GIC blocking devices to the substations, these reactive losses have drastically reduced. In addition, simulation results of the same test system by using PSCAD platform are obtained to investigate hysteresis and harmonic results during system operation and the presence of GIC.