Transformer failures in regions incorrectly considered to have low GIC-risk

A close association has been identified between the theoretical calculation of geomagnetically induced currents (GICs) in a large network, practical measurements of GICs, the results of dissolved gas analysis (DGA) records, and damage in recently failed transformers in Southern Africa. Together these indicate that GICs may contribute significantly to transformer failures on large transmission systems in mid-latitude regions, where GICs are generally thought not to be significant.