Optimal Planning Method Of Distribution Transformer Network For Seasonal Load

With the promotion of a number of national special projects of rural power grid,the density of seasonal loads such as agricultural irrigation and electric heating has been greatly increased.After these loads are connected to the power grid,the utilization rate of equipment has been greatly reduced,and the power supply economy has been significantly reduced.This thesis studies the load characteristics of rural areas as well as the planning and operation of distribution transformers,putting forward an optimization planning method of distribution transformer network to adapt to seasonal load,so as to improve the reliability of rural power grid.The main contents are as follows.(1)This thesis analyzes the global energy situation,the characteristics of power industry and the proportion of distribution transformer power loss in power system power loss,and summarizes that it is urgent to improve the operation efficiency of distribution transformer.At the same time,the characteristics and causes of rural power grid load are analyzed,and the problems faced by rural power grid are put forward.(2)Through the research on the application of various optimization methods in substation planning by many scholars at home and abroad,the advantages and disadvantages of these optimization methods are summarized and analyzed.Through the study of the development process of improving the power supply economy of distribution network at home and abroad,combined with the theoretical system of transformer economic operation research,this thesis summarizes the planning methods for improving the operation economy of distribution transformer in the area with high proportion of seasonal load by studying the development process of improving the power supply economy of distribution network at home and abroad,and the advantages and disadvantages are analyzeds.(3)Based on the above analysis and research,according to the load complementarity and operation flexibility,this thesis proposes an optimal planning method of distribution transformer network for seasonal load.The main idea is to establish a low-voltage tie line between distribution transformers.According to the characteristics of seasonal load,through the change of tie switch state,the operation mode is altered,so that some distribution transformers will be out of operation in low load season.At the same time,the optimization solves the problem of fault load transfer and thus improves the reliability of rural power grid.In the process of solving the model,considering the limitations of the basic differential evolution(DE),a local enhancement operator is further introduced.(4)The feasibility of this method is verified by selecting typical power supply areas for distribution transformer network planning.This method is compared with the general planning scheme and the one adopting on load capacity regulating distribution transformer to confirm the superiority of the proposed method.The adaptability analysis is given to enhance the expansibility of the scheme.The above analysis shows that the method is conducive to reducing the no-load loss,achieving the dual purpose of improving the reliability and economy of power supply.It is of great significance to promote the enterprise and maintain the sustainable development,and provides new ideas for the advances of the power grid in the coal-to-electricity areas.