Insight into impact of geomagnetically induced currents on power systems: Overview, challenges and mitigation

During Geomagnetic Disturbances (GMDs), the variation in the geomagnetic fields produce the electric field, which finally drives Geomagnetically Induced Currents (GICs) in electric power systems. In the last few decades, a range of detrimental effects of GICs has been observed. These effects include the heating and harmonic generation due to half-cycle saturation of transformers, vibrations in generators, unwanted tripping of protective devices, increased reactive power demand, and voltage sag. Also, the complete shutdown of a power system can be occurred due to the flowing of large magnitude GICs. In the future, substantial research will require to reduce the GIC impact on the operation of power systems. The main aim of this paper is to explore the expected challenges for power systems attributed to GICs. Towards this aim, the mechanism of GMDs and GIC is discussed first. Subsequently, the effect of GICs on various power system apparatus, namely, power transformers, generators, current transformers, relays, HVDC networks, and communication systems of utilities, are rigorously evaluated. Besides, this survey also comprises the discussion on the different mitigation techniques for reducing the GICs effect. Finally, the significant remarks are discussed for future research of the GICs effect on power systems. © 2020