Insertion transformer modeling for improved high voltage regulation of a partial discharge analyzer for dielectric voltage breakdown analysis

An accurate method of modeling a two-winding transformer is presented. It is intended that this type of modeling be completed before the physical installation of a transformer into an existing electrical circuit. The first evaluation is to mathematically derive information from the transformer by means of physical measurements and calculations only. Next the electrical characteristics are obtained by means of open and short circuit testing, where an actual potential is supplied, and measurements taken using digital and analog multimeters. Lastly, a computer program is used to simulate the modeled circuit. Data from all three tests is then reviewed for correlation. The model used, a “T”-model, considers the capacitance of the windings to be negligible, and is ignored. The model presented also assumes that the inductive reactance is much larger than the winding resistance, and therefore dominates. As will be seen, the close correlation of the data indicates that the assumptions that are made to do this analysis are valid