Improving the system unbalance and losses of distribution feeders based on transformer rearrangement

Unbalanced transformer connections cause line losses and is a reason for the possible ground current relay to trip in the distribution systems. In Taiwan, the feeder line loss introduced by transformer connections could be very serious in a practical three phase feeder, especially the open wye-open delta (OYOD) connections. If the losses and imbalance become critical, load reconnections are needed. Owing to the intrivial nature of OYOD transformers, the reconnections are not easily implemental. In this paper, load reconnection of the prime phase sequences was used. The genetic algorithms (GAs) have been implemented to solve the problem. Practical examples of Taipower Company (TPC) demonstrate the effectiveness of the proposed method.