Electromagnetic Transients in a Line-Transformer Cascade by a Numerical Laplace Transform Technique

The purpose of this work is to present a method for studying electromagnetic transients appearing in a power network consisting of a long transmission line and a transformer connected in cascade. An exact equivalent circuit representation of the system is developed using distributed element analysis in the s-domain. The proposed model assumes distributed inductances and self and mutual capacitances within the transformer windings. In addition, the new model can easily account for various connections of the transformer neutral. The line, which can be of any length, is represented by a single exact two-port network which is derived from distributed parameter theory. The new model yields closed form expressions in the s-domain for the transient potential distributions along the turns of the transformer winding as well as the connecting transmission line.