Comparative analysis of exciting current harmonics and reactive power consumption from GIC saturated transformers

Geomagnetically induced currents (GIC) can cause severe transformer half-cycle saturation. This paper introduces a simplified method based on the equivalent magnetizing curve of the transformer to estimate harmonic currents and MVAr with only the given the GIC and nameplate and core design information of the transformer. The simulation method is validated with the field results. The simulation methods are validated with observational and field test data for transformers experiencing half-cycle saturation.