Synchronous Generator Vulnerability Assessment Against Solar and HEMP MHD-E3 GIC

The solar storm or a high-altitude nuclear detonation leads to geomagnetic disturbance (GMD) that causes the flow of geomagnetically induced current (GIC) in the power systems. The GIC leads to half-cycle saturation of generator step-up (GSU) transformers that causes negative-sequence currents to flow in the generator's stator windings. This in turn leads to excessive rotor vibration, heating and generation fluctuations, thus threatening the grid reliability and resiliency. This paper performs the vulnerability assessment of the most-widely utilized power generation resource i.e. synchronous generators against GIC by performing a detailed harmonic analysis and depicting the resultant mechanical, electrical and thermal repercussions. The simulation is performed in PSCAD/EMTDC for a 13.8kV/120MVA grid-tied synchronous hydro-generator impacted by a GMD. The simulation results highlight the significant threat facing the highly prevalent generation facilities that are largely unprotected against the adverse effects caused by the GMD on power systems.