Numerical investigation for transient electromagnetic force computation of power transformer during short-circuit condition

Abstract

A power transformer has complex geometry comparing with other electric machines. So it needs a lot of computing time when we deal with the transient problem such as short-circuit characteristics of a power transformer. In this paper, we proposed an efficient numerical technique to compute transient electromagnetic force of a power transformer during three-phase short-circuit condition. In order to analyze the transient electromagnetic force acting on every disk of transformer windings, we made a simplified axi-symmetric model. First, the transient short-circuit current is calculated by using a short-circuit equation. Next, the transient short-circuit electromagnetic force due to the short-circuit current is computed by finite element method with a simplified axi-symmetric model. The proposed numerical technique is expected to be useful in the short-circuit duty design and structure design of the power transformers.