Effect of transformer sizes and neutral treatments on the electromagnetic transients in transformer substations

This paper deals with the electromagnetic transients in transformer substations. The substation can have more than one transformer. Generally, these parallel-connected transformers can be of different sizes and neutral treatment. The substation is fed from a high voltage overhead transmission line (or cable). Emphasis is given to the substation terminal voltage, the transformers´ neutral voltages (if their neutrals are not directly earthed) as well as the internal distribution of transient voltages along the transformers´ windings. Following a typical external double-exponential surge voltage, the distributed parameter transient analysis is done in the s-domain, and then followed by a numerical Laplace inverse transform technique to get the distributions in time domain