Catastrophic impacts of geomagnetic disturbances on power system operation: Analysis and Mitigation

George Washington University, Washington DC

Investigators

Abstract

Solar storms, caused by the violent outburst of explosive activities on the sun, may lead to geomagnetic disturbances (GMDs). During GMDs, a large mass of charged solar energetic particles escapes from the sun's halo, travels to Earth, perturbs Earth's magnetic field, and gives rise to undesirable dc currents in power systems. This results in overheating, overloading, and abnormal operation of power system equipment. As a result, GMDs have demonstrated the ability to disrupt the normal operation of power grids and cause widespread blackouts. The collapse of the Hydro-Quebec system is a prominent example, where more than six million customers were left without power, and major power system equipment was damaged; this episode resulted in economic damages of approximately $300 million. Experts estimate that a severe GMD has the potential to cause widespread, long-term losses with a recovery time of four to ten years and staggering economic losses of $1-2 trillion. The main goal of this project is to accurately model the impacts of GMDs on the normal operation of bulk electric power systems and develop systematic approaches to mitigate these impacts, including power grid reconfiguration and determining proper placement of blocking devices. To achieve the main goal of this research project, the following two objectives are defined: Accurate modeling and analysis of GMD impacts on power systems, and systematic mitigation of GMD impacts based on power system reconfiguration and blocking device installation. To this end, the major contributions of this project to the scientific community are as follows: 1) Spectral element analysis of power transformers: This will be the first attempt in applying spectral element method to power transformers and generally to any electric machine. Due to its compact formulation and use of high order basis functions, this technique requires much less memory and CPU time compared to traditional finite element methods and hence provides more accurate results and a better and more efficient platform for the analysis of electric machines. This project benefits from the results of this task by better transformer saturation modeling; impact of GMDs on transformers is the root cause of all GMD adverse impacts. 2) Nonlinear harmonic power flow analysis: Certain nonlinear phenomena, such as transformer saturation, can give rise to power system harmonics. This project seeks to develop a comprehensive approach for estimating the harmonic content of system voltages and currents under these circumstances. Despite the great deal of effort on this problem and past advancements in the area, to date no robust solution technique exists for large-scale problems. 3) Optimization-based GMD mitigation: To prevent GMDs from causing widespread blackouts, measures such as power system reconfiguration and blocker device installation can be taken. Power system reconfiguration aims to provide an improved stability margin to the power system or prevent the propagation of undesirable DC currents in the system by means of equipment planned outages. Blocker device installation aims to block the GICs from circulating in the grid by installing high-impedance hardware devices. This project will create systematic approaches based on optimization techniques to determine optimal mitigation strategies while ensuring consideration of power system stability and equipment loading limits. In summary, this project will create accurate modeling techniques and mitigation approaches to prevent GMD from having severe impact on the grid. Moreover, the deliverables of this project will also contribute to broader applications in general power system modeling and analysis.