A comprehensive comparison between three practical topologies of the load-balancing transformers

Load-balancing transformer is a three-phase transformer which has a pair of additional coupling winding in the secondary-side of each phase. One of the coupling windings from each phase is in series with that of the other phase and the set of these two windings is reversely paralleled with the secondary winding of the third phase. Under unbalanced condition, the unbalanced current flows through the coupling and secondary windings that each winding is fed from primary by using a separate phase. In this way, part of excess current of one phase is transferred to the other phases. In this paper based on the original load-balancing transformer, two new load-balancing transformers are presented. Two proposed and original load-balancing transformers are simulated with MATLAB and the results are discussed.