A method of analysis of transformer impulse voltage distribution using a digital computer

With the increasing need for economical design of transformer insulation in large present-day power transformers, it is highly desirable to be able to predict at the design stage the distribution of impulse voltages throughout the windings. The paper presents a method of impulse voltage calculation using high-speed digital computer techniques which appears sufficiently accurate and flexible to provide a basis for a routine design procedure. The derivation of the transformer equivalent circuit is discussed, together with the computer programme for the solution of the resulting differential equations. The advantages of the method are indicated, and the results are compared with other recent theoretical work and with direct tests on an experimental transformer. The relative importance of the various winding parameters in the construction of the equivalent circuit is determined experimentally. Finally, possible extensions of the method are discussed and the possibility of complete automation of the procedure is indicated.