Impact of GICs on Power Transformers: Overheating is not the real issue.

There has been some misconception in the electric power industry that geomagnetically induced currents (GICs) can cause significant overheating damage to the majority of medium and large power transformers. Because of the nature of GICs, the majority of power transformers would not experience damaging overheating because of them. This article presents the real issue with GICs, which is that the combination of the increase of reactive power absorption and injected current harmonics into the power system could result in compromised grid stability.