GICharm: A System Level Analysis Tool for Geomagnetic Disturbance Related Harmonics

Power systems can and have been impacted by harmonics generated during geomagnetic disturbances (GMD) events. These harmonics are generated from the part-cycle saturation of power transformers caused by the flow of geomagnetically-induced currents through grid-connected transformers. This article describes a system level harmonic analysis tool needed by the industry to perform an adequate assessment of GMD-related distortion impacts. When the results of a properly performed harmonic assessment are combined with the fundamental frequency analyses, a much more accurate evaluation of grid security during GMD can be obtained. The tool is publicly available for engineers, students, and researchers. It provides multiple examples, including a validation against published measurements from an experimental setup consisting of two back-to-back connected transformers in the Fingrid power network. Final of this article briefly discusses the results of that validation.