The optimal switching strategy of transformers based on the cost

Abstract

Transformers are widely used in power system. The active and reactive loss will be caused by transformer in the process of changing the voltage and transmitting power, and its active power loss accounts for the total loss of the network as much as 30%. So it is significant for energy saving and consumption reduction to analyze the economic operation of the transformer. In the paper, two double-winding transformers are set as an example. Firstly, integrated power losses under different operating conditions are calculated, and the economic operating interval is obtained by using the critical point method. Secondly, the nonlinear least square method is used to fit the predicted load data to get the fitting curve, and possible switching points are obtained through by combining the fitting load curve with the critical point method. Then the cost and benefits that arise when a transformer changes its operating state at possible switching point are calculated, so energy-saving profits in economic operation interval are got. Finally, the work of a certain period of time is arranged, that is, a number of switching actions are needed to be arranged to increase the possibility of access to energy-saving profits. And then switching points which can get more energy-saving benefit are obtained, at last the optimal switching strategy of the transformer is organized.