Combination Optimization Of Transformer Economic Operation Mode In Power Distribution Network

Transformers are widely used in power system. Transformer loss occupies a large proportion in the power system. Studying transformer economic operation to reduce its loss farthest is one of the effective measures to decrease the network loss and save electric energy. Therefore, in order to decrease the network loss in power system, it is crucial to optimize transformer operation mode.Transformer economic operation relates to make full use of existing equipment to maximumly lower transformers loss by selecting reasonable operation modes, optimally adjusting load curve, optimizing combination of running position, improving current operation conditions and other measures, on the basis of insurable safe operation, under the condition of supply the equal power.Firstly, the basic concept and research status of transformer economic operation have been introduced, and transformer technical parameters have been stated. Based on the principles of economic operation, how transformers realize economic operation in several different situations is analyzed.Secondly, the enumeration approach is introduced into combination optimization of transformer operation mode. Under constraints of connection form and transformer load, all possible operation combinations are enumerated. In the case of load data given, the optimal operation mode of transformer combination is chosen. With the change of load data considered, the optimal operation mode combinations corresponding to different load level are obtained based on full enumeration approach, and economic operation regions corresponding to different operation mode combinations are selected. If load fluctuation is flat, transformer operation mode could be switched based on economic operation region; otherwise, the optimization method of transformer economic operation during a period of time is described based on short-term load forecast. The saved power energy when operation mode is adjusted is calculated based on the forecasted load curve and the optimization model. Then it is compared with the power energy converted to switching costs, and the reasonable operation mode is determined. Thus, switch times are largely reduced. As a result, security and reliability of the system is improved.Finally, when load fluctuation is flat, the optimization method of transformer economic operation at a certain time is combined with the specific example. Under constraints of connection form and transformer load, the optimal operation mode combination is selected. With the change of load data considered, the optimal mode combination corresponding to different load level are obtained, and economic operation regions corresponding to different modes is chosen. When load fluctuates frequently, the optimization method of transformer economic operation during a period of time is combined with the specific example, power savings are calculated based on objective function and the reasonable transformer operation mode is determined. Results of calculation example show that the described model and approach are effective and practical.