Reactance calculation of a reactor with non-concentric windings by utilizing a finite element method (FEM) based 3-D program

This paper describes a modern method to calculate the saturated and non-saturated reactances of quasi-linear reactors. The reactor studied is a single-phase unit with two non-concentric windings without magnetic core, but with magnetic shields and tank. This geometry requires 3-D calculations. To achieve the highest accuracy, a FEM based 3-D program with a time harmonic solver was utilized to calculate the reactive energy in the system. With the reactive energy, the reactance is calculated. Simulations were made to calculate the total and the self reactances. The mutual reactance was calculated by two means, with aid of magnetic circuit theory and by making a separate simulation. The calculated reactances were compared to the measured reactances of an actual full-size manufactured reactor. The deviation between calculated and measured reactances was negligible. Hence, the design reliability to meet the guaranteed reactance value and tolerance was significantly enhanced, thanks to the calculation method utilized.