Research And Realization Of Distribution Network Planning

Distribution network planning is an important component of national economy and social development in power supply district. It is also the vital preparatory work of power system for expansion. Along with the increasing of distribution system load, the higher quality and reliability are demanded. The great benefits of social and economic can be achieved through reasonable distribution network planning.This paper is completed on the basis of the actual participation in the project "the 11th Five-Year Plan of Wuyang's electric network development planning". The methods of distribution network planning are studied from four respects such as power load forecast, power flow analysis and short-circuit current calculation, distribution network optimization and line loss calculation. Main works as following.(1) Some traditional load forecast methods such as electricity each consumption method, elasticity coefficient method, regressive analysis and grey theory forecast method are discussed. These methods have their own characteristic and adaptive arrange. Because of simple model, explicit conception and convenient calculation, they can meet the demands of load forecasting in the general circumstance and be widely used for a long time. Based on these methods, the combined forecast model is introduced. It organically combines several different forecast models together and synthesizes the advantages of these models. It can improve simulating ability and forecast precision. Good results are obtained by applying these methods to forecast load level of Wuyang county in the year 2005～2015.(2) With regard to the characteristics of distribution network, the appropriate algorithms are adopted to calculate power flow and short-circuit current of Wuyang distribution network for planning year. An application of power system calculation programs which have visual man-machine interactive interface can improve efficiency and enhance the scientific literature and reliability of power network planning.(3) The model of distribution network optimization is established. An artificial immune algorithm is used to solve the model. Compared with genetic algorithm , it increases antigen's memory and identification ability. In addition, the calculation of affinity among antibody is increased in immune algorithm. It obtains the diversity of antibody. Therefore the global optimum is ensured. In view of the radiation characteristics of distribution network, by using graph theory knowledge, the coding method which regards new node as the gene of chromosome is adopted to avoid the radiation inspection and improve the speed of evolution.(4) The theoretical line loss calculation program based on node number is developed. Node number gives a description of network topology. According to electrical components graphics information table, wiring analysis is performed, and computing network is formed automatically. After that, line loss calculation function is realized on the basis of the depth-first search strategy. The program has graphical man-machine interactive interface. It shares graphics platform, computing network and the real-time data from SCADA system with high-level application software of power network dispatching automation.The research and application of new theory and methods, and the development of planning software which has visual man-machine interactive interface, have great practical significance on improving the level of power network planning, reducing labor intensity and making more scientific decision of distribution network planning.