Dynamic Model of a 20-Bus Power System for HEMP/GMD Controls-based Mitigation Design

A high altitude electromagnetic pulse (HEMP) or solar-geomagnetic disturbance (GMD) has the potential to severely impact large-scale electric power grids. This is due to the introduction of low-frequency geomagnetically induced currents (GICs), which can saturate the magnetic core of power transformers and lead to distorted ac waveforms, increased losses, and the potential for thermal damage. This paper presents a dynamic model of a 20-bus power system which includes reduced order models of saturating transformers, coupling of HEMP/GMD generated electric fields onto transmission lines, a resistive model of earth for ground conduction of GICs, and the ability to specify conventional and non-conventional mitigation strategies via an optimal controls framework. First, a description of the power system model is presented along with a comparison of the proposed dynamic model to the original static model. Subsequently, the top-down control framework for designing mitigation schemes is provided, and a solution for system control which avoids transformer saturation during a simulated HEMP/E3b insult is demonstrated. Finally, and conclusion and directions for future research are put forth.