Researched On Power Supply Capability Of Distribution Network Grid Planning

Recently,the scale of urban distribution network in China has gradually increased.In order to meet the requirements of accurate planning and management,some cities in China have introduced the concept of grid into distribution network planning.With more and more grid planning being used to solve urban power grid problems,how to evaluate the power supply capacity of grid planning has become an urgent problem to be solved.In view of the fact that the existing evaluation of distribution network power supply capacity does not take into account the hierarchical classification of grid-based power grid,this thesis carries out relevant research.The purpose of this thesis is to establish an evaluation index system of distribution network power supply capacity based on grid idea,and to evaluate grid planning from the perspective of power supply capacity.Firstly,this thesis introduces the related theories of grid planning and power supply capability evaluation,then uses fishbone diagram analysis method to analyze the factors affecting the power supply capability of distribution network from two aspects: network structure level and load supply capability.Based on the principles of systematicness,scientificity,objectivity and operability of index selection,the power supply capacity evaluation indexes of the power supply area,power supply grid and power supply unit are determined.The hierarchical structure of indicators is established by analytic hierarchy process,and the definition and calculation formula of indicators are given.Through analytic hierarchy process(AHP)and Delphi method,the weight coefficient of evaluation index is determined,and the evaluation criteria of evaluation index are established based on the guidelines and experts' experience.According to the related theory of grid planning,the grid planning of distribution network in JX County is carried out.The rationality and practicability of the evaluation system and method are verified by evaluating the case of grid planning.Through the analysis of the evaluation results,the main problems and weaknesses of the distribution network are found,and the planning,construction and transformation of the distribution network are guided.