The study on the effects of the height of the core’s window on the leakage reactance of transformers using finite element analysis

The short-circuit transformer’s behaviour can be easily predicted from its leakage reactance. The relationship between the height of the core window and leakage reactance of the transformers according to almost all of the analytical methods is assumed to be constant under different heights of the core window. This approach is not significantly accurate during severe cases such as those has small differences between the core height and winding height. Finite element analysis is computer software which can help manufacturers and engineers to speed up the process of optimising electrical machines. In this work, a finite element method is used to see the effect of the window height on the leakage reactance of the transformer under the different heights of the window of the core. The three-dimensional methods are used to evaluate the leakage reactance of the transformer for different heights of the core window. The results show that the transformer’s leakage reactance widely varies during the change in the height of the core window for the same geometry of the windings and electrical parameters of the transformer. Hence using analytical methods could result in inaccurate results. Moreover, considering the same ratio between the window height and windings height is no longer valid for all of the transformers.