Analysis method for loss evaluation considering the half-turn effect in three-phase autotransformers

In order to reduce the size of transformers and simplify the lead design of them, the half-turn effect in three-phase autotransformers has been evaluated using the finite element analysis. In this paper, the transient analysis method using the external circuit which represents the three-phase load loss test condition is proposed to evaluate the change of load loss by the half-turn effect. From the result of the transient analysis, we found that the change of load loss by the half-turn effect in three-phase three-limb transformer did not occur and verified the above analysis result through the three-phase load loss measurement test. Therefore we think that the proposed analysis method can be used to evaluate the half-turn effect in three-phase autotransformers.