Optimal Active Power Dispatching Of Microgrid And Distribution Network Based On Model Predictive Control

Nowadays,the excessive consumption of fossil fuel is causing an energy crisis and making the environmental pollution more severe.Therefore,distributed generation using renewable energy gets wide attention because so far it's a clean way to acquire massive energy.Microgrid is a kind of effective system to integrate the DGs and access to the utility grid.Since the proportion of DGs is rapidly increasing in the regional distribution network,figuring out the coordination optimal dispatching between the microgrid and the distribution network to realize the reduction of the renewable energy power generation,decrease the influence of distributed generation on the distribution network and enhance the economical efficiency of utility grid has attracted increasing attention in the field of power system.This thesis begins with a discussion on the development of distributed generation and microgrid,summarizes the development of microgrid at home and abroad,analyzes the research progress of microgrid and active distribution network in optimal scheduling,and states the research significance of the thesis based on the practical situation.Besides that,the second chapter analyzes the drawbacks of the traditional dispatching pattern where there are large amount of DGs in the distribution system,then combined the hierarchical control with the energy management strategies,puts forward a three-level coordinated dispatching architecture for the distribution systems and microgrids.In addition,it studies the multi-time scale optimal scheduling of microgrid based on model predictive control(MPC).Based on the analysis of the operating characteristics of microsources and energy storage in microgrid,this study establishes the cost model;In the day-ahead scheduling phase,it regards the minimum cost of microgrid integrated operating cost including operating cost,environmental management cost and fuel cost as the goal,and applies the improved genetic algorithm to achieve the economic optimization of microgrid operation;As for the intra-day optimization stage,this thesis proposes a multi-time scale rolling optimal strategy for microgrids on the basis of linear state space model predictive control algorithm,modifies the operation plan of intra-day short-time scale in the adjustable unit of the microgrid and realizes the smooth tracking of the microgrid connection point tie-line power.Finally,according to the proposed three-layer coordinated dispatching architecture of the distribution network and microgrid,this thesis studies the coordinated dispatching of the distribution network and microgrid.It analyzes the influence of distributed power supply access on the distribution losses and node voltage.Taking the network loss as the optimization target,it considers the operation constraints such as distributed power generation elimination on the spot and centralized storage,solves the model with the help of the modified branch current back/forward sweep method and genetic algorithm to complete the optimization of the distribution network layer scheduling,provides the microgrid day-ahead operation plan.Later,it adopts simulation example to conduct contrastive analysis and verify the feasibility of the method.