Kalantar - Iran University of Science & Technology
Kazemi - Iran University of Science & Technology
Tajfar - Iran University of Science & Technology

This paper deals with the issue of coordination of cascaded tap changers in radial distribution feeders. Poor coordination causes unnecessary operations of the tap changers and consequently unnecessary wear as well as poor voltage quality. A new fuzzy-rule-based controller that coordinates tap operations at different voltage levels is proposed and compared to noncoordinated ontrol scheme in this paper. Simulation system consists of three distribution transformers and their tap changers of 130/50kV, 50/20kV and 20/10kV. Simulation results indicate that the proposed fuzzy rule based controller reduces the daily number of tap operations by a high percent compared to the non-coordinated controller.

fuzzy logic, coordinated control, Radial distribution network, OLTC, Voltage profile