An Improved Power Transformer High Frequency Model for Transient Overvoltage Studies

In modern substations, some impinging transient surges may coincide with a power transformer's natural frequencies. This can cause considerable voltage building-up inside the transformer windings and impose significant stresses to the transformer insulation. In this paper, we propose an improved high frequency transformer model for transient analysis. Using the proposed model, resonant over-voltages built up inside the transformer windings are analysed. The proposed transformer model is also applied to transient analysis of power system networks.