Application of zigzag transformers for reducing harmonics in the neutral conductor of low voltage distribution system

The use of zigzag transformers for reducing harmonics in the neutral conductors of a three-phase, 208 V/120 V distribution system is presented. Third-harmonic currents add up in the neutral conductor of the distribution system, thereby feeding nonlinear loads. Other solutions to this problem include derating the size of the distribution transformer by 50%. Application of the zigzag transformer eliminates the need for this derating. Measurements of current draw before and after the installation of a zigzag transformer are presented.<>