Autotransformer design with zig-zag connection Zna0

The autotransformer which is supplied by network without neutral wire must be loaded symmetrically. Already small unsymmetrical load causes significant voltage imbalance and overvoltage. When the fully loading of one phase is required, the zigzag autotransformer connection must be used. This paper describes the behavior and design of autotransformers under unsymmetrical loading conditions.