Research On Comprehensive Evaluation Of Grid-connected Micro-grid Projects

Grid-connected micro-grid is an effective solution for large-scale distributed renewable energy grid connection,and greatly improves the reliability of power supply,so it has been considered as an indispensable part of the future energy Internet.At present,the operation and control technology of grid-connected micro-grid has been basically mature,but its economy and final implementation effect have no case reference,which restricts the promotion of grid-connected micro-grid project.Although our country has carried out the construction and promotion of grid-connected micro-grid demonstration projects in view of these problems,grid-connected micro-grid system is a complex system with strong comprehensiveness and many interactive fields.There is no effective method to evaluate its final effects scientifically and to provide basis for the development of grid-connected micro-grid project.This requires comprehensive evaluation of grid-connected micro-grid projects,which can explain the operation benefits of micro-grid project,provide with the basis of investment decisions for operators,and provide strong support for the construction and commercial promotion of grid-connected micro-grid in China.Therefore,this paper focuses on the comprehensive evaluation of grid-connected micro-grid projects.The main work is as follows:First of all,by referring to the relevant literature,this paper analyzes the characteristics and classification of micro-grid projects,and summarizes the advantages,disadvantages and adaptability of different types of micro grid projects.Then,the main operation mode of grid-connected micro-grid project is described.Finally,according to the possible impact of micro-grid projects,the evaluation system construction ideas are sorted out.Secondly,according to the possible impact of micro-grid projects and the principle of index system construction,a set of index system is constructed which combined with the characteristics of grid-connected micro-grid projects.The index system is developed from five aspects:construction economy,safety reliability,planning coordination,development environmental protection and utilization efficiency,and each evaluation index is defined and introduced in detail.Then,a reasonable evaluation method is selected on the basis of investigating the commonly used comprehensive evaluation methods,which combined with the characteristics of grid-connected micro-grid project.Through the combination and optimization of evaluation methods,a comprehensive evaluation model suitable for grid-connected micro-grid project is obtained.PCA is used to select the important evaluation indexes,reduce the redundancy of the indexes,and then entropy method is used to objectively weight the evaluation indexes.Finally,PROMETHEE method is used to evaluate and rank the micro-grid project schemes on the basis of considering the preferences of investors.Finally,taking Lanzhou Science and Technology Innovation city grid-connected micro-grid demonstration project as an example,the evaluation index system and comprehensive evaluation model are empirically analyzed.The feasibility of the theoretical method is verified,and each scheme of the project is analyzed.The research results show that grid-connected micro-grid can balance the negative effects of intermittent power supply and energy storage facilities in the system,and provide theoretical basis for the promotion of micro-grid engineering.