Research On Comprehensive Evaluation Index System Of Medium Voltage Distribution Network Based On Complex Network

With the increasing requirements in the penetration rate of new energy,the quality of power supplying and the aesthetic of urban planning,to power supply companies,the effective excavation of irrational and weak links in the distribution network grid has become an important focus of the distribution network planning and transformation.Based on the analysis of the distribution network structure,and combined with complex network theory and risk theory,a set of comprehensive evaluation index system and evaluation method of distribution network grid is proposed to provide reference for grid planning.Firstly,according to the design principles of medium-voltage distribution network grids and the characteristics of typical wiring methods,a quadratic simplified model is used to reduce the complexity of network topology,Such as node equivalence,parallel loads mergence and branch lines shrink.It transfers a high information redundancy network into a simple topology diagram,composed of key nodes and branch lines,which can represent the network structure of original distribution network.The simplify of original network provides a topological basis for the calculation of indicators for comprehensive evaluation of distribution networks.Secondly,the complexity of the distribution network grid structure is analyzed to explore the common characteristics between the distribution network and the complex network.The common evaluation indicators of the complex network are studied to find out the feasibility and limitations of application in the distribution network.Then,according to the principle of comprehensive evaluation,the unique structural characteristics and properties of distribution network grids,a series of vulnerability evaluation index of distribution network grid,mixing complex theory and risk theory,are proposed from aspects of node layer,line layer and system layer.Some examples are display so as to verify the validity of some indicators including node importance index,line importance index,node risk index,line risk index and system risk index.Thirdly,based on comprehensive evaluation index system of distribution network,the IEEE69 nodes system and the local grid of a distribution network in a county of City-Y are evaluated from single-power and single-bus system to multiple-power and multiple-buses system,from local analysis to overall analysis,from micro analysis to macro analysis.So that the weak links of the current grid are dug out.Besides,it is the ability of distribution network to cope with load growth that is analyzed according to the changes on the load side.Which offers a reference for the preparations for network plan.At last,some suggestions are given from the results of grid evaluation.