Comprehensive Evaluation Method Of Distribution Network Planning Based On Improved Analytic Hierarchy Process

With the development of national economy and the progress of science and technology, the need for electricity rise sharply. In order to meet the end users of electricity demand, we must strengthen the construction of the power grid. Before the construction, some planning program of power grid construction should be put forward. A reasonable planning program can promote the development of the national economy, improve people's living standard and bring huge economic benefits to power grid enterprises. So it is very important to evaluate planning program of the power grid.Analytic Hierarchy Process(AHP) is a comprehensive evaluate method which is widely used. It breaks down complex problems into hierarchical structure. In each layer, decision makers judge the relative importance between the elements by pairwise comparison, using scale systems to quantify the judgment, constructing judgement matrix, using mathematical method to calculate the element weight. Finally,each planning program weight multiplied with corresponding weights and integrated within the hierarchical structure to get the relative importance of each program to the general objective. Then, rank the programs and pick the most suitable one according to the relative importance of the planning program. As can be seen from the AHP evaluation process, weight calculation has strong subjectivity and the evaluation measurement is very single. In view of the insufficiency in the evaluation process of AHP, this paper has did some research.The weight calculated by traditional AHP just reflect the attention degree of decision makers between each index, but does not reflect the characteristics of index data. Therefore, this paper introduces the theory of variable weight to adjust the index weight. In view of the traditional variable weight calculation method of state variable weights vector selection is difficult, the feature of operability is not strong, and this paper puts forward a variable weight calculation method based on shape similarity. This calculation method avoiding the selection of the state variable weight vector; adjust index weight by setting the reference sequence. Through example analysis, demonstrates the rationality of the method put forward in this paper.The traditional AHP uses the final weight of the planning scheme to evaluate the merits of the planning scheme. Final weight is just a kind of measurement, it cannot evaluate the planning scheme allsidely. Therefore, this paper puts forward a grey relational analysis method considering balance. This paper introduces a new relative correlation degree method which combines TOPSIS with grey relational analysis. Relative correlation degree can be used to evaluate the proximity between the planning scheme and ideal scheme. Meanwhile, slope correlation degree is introduced, and this paper proposes a new ideal that slope correlation degree can be used to evaluate the balance of each index levels. Then, this paper combines relative correlation degree with slope correlation degree, constructs comprehensive correlation degree. Decision makers can choose the most suitable planning scheme according to the number of comprehensive correlation degree. Compared to the traditional Analytic Hierarchy Process, comprehensive evaluation method proposed in this paper can evaluate the planning scheme allsidely. Actual case analysis shows that comprehensive evaluation method proposed in this paper has strong operability, and the evaluation result is reasonable.