Review of Electrical - Power Transformer Responses to Fast Transients

Power transformers in the power grid are vulnerable to both man made and natural threats. This paper documents a literature search on the effects of fast electrical transients on power system transformers, for the purpose of estimating the effects of a high-altitude electromagnetic (HEMP) environment on transformers. In this study, data for both the HEMP signal attenuation and distortion as it propagates through the transformer, and for possible damage to the transformer has been found, and the measurement programs that developed these results are discussed. Unfortunately, only a limited number of results have been found, so the generalization of these measurements to a wide variety of different transformers is difficult. However, these results do provide some insight into transformer operation in an HEMP environment.