New Solid-State on-Load Tap-Changer Topology for Distribution Transformers

High controllability advantages of power electronic switches led to their application in tap-changers of distribution transformers. Using such switches lends itself to quick operation of the tap-changer and thus improved performance. Their application reduces maintenance and repair costs of tap-changers. This paper introduces a new solid-state on-load tap-changer topology that has many steps with fewer power electronic switches compared to those reported in the literature. This tap-changer is designed for an 800 kVA, 20 kV/400 V distribution transformer, and the results are discussed.