Study Of The Power Network Planning Model Based On LCC And The Comprehensive Decision-making Method

Power network planning is an important part of power system planning.Power network planning is an important work to ensure the stable development of power system.Because of the long-term and systematic characteristics of power system,the costs of operation and maintenance stage and fault stage account for a large proportion of the LCC of power neywork.Traditional power network planning only pays attention to the costs of investment of power network,but neglects the costs of operation,maintenance,failure and discard of power network.In order to make up for the shortcomings of traditional power network planning,this paper studies the power network planning model based on LCC and the comprehensive decision-making method.In this paper,the LCC theory is applied in every segment of power network planning and the main research contents are as follows:1.The whole process of power network planning from planning and construction stage,operation stage and maintenance stage to disposal stage is analysised deeply.The costs of power network planning scheme is analyzed according to system and process,and the LCC model of power network planning is established.The theoretical foundation of the LCC theory application in power network planning is built.The N-2 test is necessary in calculating CF and the process of N-2 test is rather complicated.In this paper,a method of N-2 fault set rapid screening which is based on risk factor and fuzzy theory is proposed.The risk factor and N-2 ordering index are defined.By adjusting the parameter,this method can reduce the number N-2 fault set needed to calculate,greatly improve the computational efficiency.2.In order to overcome the defect that power network planning model is proposed with minimum LCC does not contain significant social costs caused by power shortage,a power network bi-level differential planning model is established.The performance of backbone gird is measured by three aspects: topology,power flow and cost.The model for building the backbone grid based on LCC and comprehensive importance of component is developed.It combines with the power network planning model that is proposed with minimum LCC to form a power network bi-level differential planning model.Because the calculation of the line betweenness index is slow,based on the symmetry of the weight matrix and the nature of the shortest connected path,an improved Floyd algorithm is proposed to improve the computational efficiency.The random binary particle swarm optimization algorithm is applied to solve the bi-level planning model.The reliability of important load is improved by strengthening the lines in the backbone grid.On the premise that LCC is small,the social costs caused by power shortage of important load should be minimized.3.Firstly,according to developing features and basic attributions of power network planning,a SECA power network planning comprehensive evaluation index system which is based on safety,effectiveness,cost and adaptability is established.Secondly,the Delphi-entropy weight comprehensive weight calculation method based on the game theory model.Then based on absolute ideal point theory and close-degree projection,TOPSIS method is improved.A comprehensive evaluation method based on improved TOPSIS-Delphi-entropy weight is used to evaluate power network planning schemes.The method based on the combination of TOPSIS method with the comprehensive weight calculation method can make full use of objective data.It has the advantages of simplicity,practicality and maneuverability and the weight of this method is reasonable.