Computer aided analysis and design of power transformers

In this paper, an integrated, three-dimensional, finite element package for the analysis and design of power transformers is developed, requiring no prior user experience in numerical methods and magnetic field simulation. The package consists of an automated pre-processor, magnetostatic solver and post-processor. High accuracy, low computational cost, minimization of user interaction and functional interface are the main advantages of the software, rendering it a powerful computational tool for characteristics prediction of single and dual voltage transformers, suitable for an automated design environment. For the development of the package, a particular scalar potential formulation was adopted. This method, in conjunction with the detailed representation of the real transformer geometry enables the achievement of high accuracy with the use of meshes of low density. The computational efficiency is also enhanced by the use of Morse technique for the storage of finite element matrices and Preconditioned Conjugate Gradient method for the solution of the finite element equations. The software has been incorporated in the design process of a transformer manufacturing industry for the evaluation of the leakage field and short-circuit impedance. The comparison of its results with measured values indicates the improvement of accuracy in comparison to the existing methodology, resulting in reduction of the design margin. Moreover, its employment has contributed to the decrease of the transformer industrial cycle and production cost.