The Study Of Reliability Evaluation And Optimal Planning Method For Standalone Microgrid

With the aggravation of the energy crisis and the environmental problem,the distributed generation technology using renewable energy resources such as wind and solar energy has become the focal point all over the world.In order to utilize the complementary characteristics of different distributed generation technology,stand-alone microgrid consisting of wind and solar power generators and other different kinds of distributed generation units is considered.As the basic task of project construction,planning and design is the core problem of standalone microgrid.In the process of planning and design,reliability have a great effect on planning schemes.Therefore,this paper principally study the reliability evaluation and the optimal planning and design of standalone microgrid.The main work of this paper is as follow:(1)This paper establishes the probability model of renewable energy resources and the disturbance model of load,and proposes a data generation method of renewable energy resources based on Markov process transition probability matrix.This paper also establishes the quasi-steady state model of distributed generation units and energy storage,and the reliability model of repairable components.(2)This paper proposes a reliability evaluation method for medium voltage standalone microgrid.In the method,a power-flow based regulation strategy is also adopted except the coordination strategies based on the active power balance.A reliability evaluation method integrated with the proposed operation strategy is presented.The case study shows the effectiveness of the method.(3)This paper presents an optimal planning model considering reliability problem for the energy storage system.In the model,the randomness of renewable energy resources,disturbance of load,uncertainty of components' failure and power flow constraints are all included in the process of solving the optimization model.The convergence of the reliability index is set as the termination criterion of simulation.The case study not only demonstrates the correctness of the method,but also analyzes the significant effect of energy storage on standalone microgrid.(4)In order to solve the problem of planning and design of standalone microgrid demonstration projects,an optimal planning software for standalone microgrid system is developed.The software can reasonably take all kinds of uncertain factors into consideration and realize the optimization of not only capacity but types of distributed generation units.The software has a strong function of technical and economic evaluation,and is applied to planning and design of standalone microgrid.The software is compared to HOMER and Hybrid2 and the result demonstrates its characteristics in theoretical method and software function.