The effects of GIC on protective relaying

This paper summarizes research and operating experience related to the effects of geomagnetically induced currents (GIC) on protective relaying. It shows that if the GIC causes high levels of harmonic distortion, there is a risk that the conventional protection system may not provide adequate protection for the capacitors, transformers, and generators. It recommends methods to reduce the risk of false tripping and the risk of failure to protect the power apparatus.