Research On Electricity Distribution Structure Planning Optimal Model And Algorithm

Distribution network planning is a complex NP—hard optimal problem with characteristics such as uncertain, non-linear, multi-objects and multi-stages. Intelligent optimization algorithm, reliability worth theory and multi—objective were adopted in this paper to do the research as follows:Firstly, In the traditional optimization design of electricity distribution network , network structure and conductor cross sections were optimized step by step,which firstly optimize network structure of electricity distribution network, and then optimize cross section of electricity conductors on basis of the optimized network structure. it is can not get the global optimization scheme of network structure and conductor cross sections. In order to deal with this problem, a integer coding method based on a electricity node for network structure and conductor sections simultaneous optimization design was put forward; An automatical method for identifying electricity flow route based on electricity node matrix transformation was deduced, an automatically calculating program of electricity power and voltage of different nodes was developed, an dynamic penalty function was used to deal with the constrain conditions. Hence, an electricity distribution network structure and conductors cross sections simultaneous optimization model and its solution method based on integer code genetic algorithm were obtained. Two different electricity network examples were used to test this method, and its results were compared with optimized schemes based on traditional optimization method, which show that the simultaneous optimization model and algorithm can reduce the electricity conductors cost of distribution network, and it can effectively get global optimization scheme of electricity distribution network.Secondly, This paper was researched and established equipment real-time fault complexity distribution network reliability assessment of model and the algorithm, for which distribution system reliability evaluation model did not consider the impact of equipment and the rule of real-time fault change impact; Section algorithm and model based different weather conditions on complexity distribution network reliability assessment was established which fully consider the rule of different weather conditions for reliability assessment, the model which makes more completely consider reliability assessment; This paper tried to take into account the indirect costs of lack of electricity power shortage cost to overcome the shortcoming of electricity loss calculation method previously, and improved the model of costs of lack of electricity power. Example shows that the model could provide assessment methods for analyzing power system fault and the load point of power shortage.Finally, the distribution network for multi-objective programming model was difficult to fully consider economy optimization and reliability of optimization of the interaction and overall coordination. This paper firstly used genetic algorithms which has global search performance and robust separately searching performance, and then coordinated between various constraints by the introduction of co-evolutionary algorithm, and finally the multi-objective mathematical model for distribution network planning was built. In order to overcome defects, such as being difficult to getting the pareto, slowly speed and sensitive to initial solution for large-scale multi-objective problem, the multi-objective mathematical model were obtained through the introduction of annealing algorithm for dynamic penalty function and the elite retention measures. Electricity network examples were used to test this method, and its results were compared with optimized schemes based on traditional optimization method, which show that the multi-objective model and algorithm could get global optimization scheme of distribution network and make the planning results of more practical significance.