An algorithm for fast calculation of short circuit forces in high current busbars of electric arc furnace transformers based on method of images

This paper proposes an algorithm for the calculation of short circuit forces on the high current busbars of electric arc furnace (EAF) transformers based on the method of images using an analytical solution for the electromagnetic force between two adjacent current carrying rectangular conductor. The theory of images is used to account for the impact of the tank walls on the short circuit forces on the busbars. The proposed method uses an iterative algorithm and increases the number of image layers to achieve the desired accuracy. A 30 MVA EAF transformer is investigated as a case study and the results are compared to 2D finite element analysis (FEA). ANSYS software is used for the FEA. The proposed algorithm converges very fast, so that only in its first iteration, the convergence error is less than 0.2%. The comparisons show that the short circuit force calculations using the proposed method, conform to the 2D FEA results. However, the short-circuit calculation time using the proposed method is about 20 times faster than the 2D FEA with the same relative error. Therefore it can be used as a faster alternative for the FEA. The proposed method is characterized by fast convergence, simple calculations and high precision.