Solar-Induced-Currents in Power Systems: Cause and Effects

This paper summarizes a research effort investigating the effects of geomagnetic storms on electric power systems. Geomagnetic storms, which are caused by solar flares, can cause spurious quasi-dc currents in power systems; these are termed solar-induced-currents (SIC). A summary of SIC data recorded on over 30 power systems across the United States is presented, and power system effects are discussed. The important problem of internal localized heating in power transformers due to SIC is presented, as well as a consideration of possible methods of mitigation of the SIC.