Power Capacity Optimization Of Isolated Micro-grid Based On Uncertainties And Load Demand Management

The Microgrid is a small-sized power generation and distribution system that is composed of distributed energy sources,energy conversion devices,loads,monitoring and protection devices,etc.It is a novel and important technical tool to keep the system operate safely and stably during the process of power generation,distribution,transformation and consumption,and also to realize efficient renewable energy consumption.Due to the strong uncertainty of distributed renewable power sources(such as wind power,photovoltaics,etc.),power load and market behavior,and the influence of load-side demand management under the guidance of different market mechanisms,traditional microgrid system capacity optimization methods face challenges.It is urgent to establish a new theoretical framework for microgrid system capacity planning and operation strategy optimization that fully takes into account the uncertain characteristics and load demand management.This paper focuses on the problems of microgrid system capacity planning and operation strategy optimization under the constraints of multiple uncertainties and load-side incentive management.It comprehensively considers the impact of the multi-scale uncertainty coupling of various elements in the microgrid.In addition,the impact of load demand management is studied and analyzed from the aspects of power constraints and power balance for different time scale uncertainties.Specifically,in view of the stochastic uncertainty characteristic of source-charge in long-term capacity planning problems,the stochastic energy network calculus theory is used to characterize the energy balance capability of the microgrid system.The robust coordination idea is used to deal with the problem of power balance constraints,which is used to ensure the power balance capability of the islanded microgrid system.In view of the uncertainty characteristics of the sourcecharge prediction error in the short-scale microgrid system optimization operation problem,we characterize it by Monte Carlo simulation in multiple scenarios and also introduce load demand management.With the above tactics,we can model the control for interruptible and translatable loads,which could optimize the load characteristics.As a result,the problem of optimal operation in the microgrid system can be solved.Meanwhile,based on the specific problem this paper transforms the microgrid planning-operation double-layer coupling problem into a mixed integer programming model,which can be solved by CPLEX that calls the internal optimization solver YALMIP to complete the efficient system solution and realize the unified efficiency and precision of the microgrid system capacity optimization problem.Finally,for the operation strategy of multi-microgrid systems,the introduction of a day-to-day electricity price pricing method based on the marginal cost effect of different microgrids is used to guide the day-to-day optimization of scheduling strategies within different microgrid operators.For scheduling problems,this paper also establishes a multi-stage and multi-process energy management and scheduling model that includes "prescheduling-coordinated optimization-rescheduling-participation willingness analysis",using multi-agent decision-making architecture to achieve coordinated optimization and coordination of energy within multiple microgrid systems management.The purpose of this paper is to construct a new theoretical framework that fully considers the nature of uncertainty and the load demand participating in the dispatch of microgrid system capacity planning and coordinated operation optimization under market incentive management.It has certain academic value and engineering significance.The main work is listed as follows.The first chapter introduces the purpose and significance of the study in this paper.Considering the characteristics of microgrid planning and operation optimization problems under the influence of uncertain environment and load management,this chapter specifically introduce the related research status at home and abroad from three aspects that are microgrid uncertainty analysis methods,load demand management strategies and analysis methods.With the above related work,this chapter put forward the main research.The second chapter mainly solves the influence of uncertainties of different time scales and demand response in the microgrid on the source-charge power prediction problem.First,the source-charge power characteristics of the microgrid system are analyzed.The uncertainty problems on different time scales and the impact of demand management are also analyzed.With specific examples the source-load power prediction characteristics are analyzed and explained in conjunction.The initial preparation of the model was made for the optimization problem of microgrid power capacity.The third chapter establishes a two-phase capacity optimization model for windsolar-diesel-storage microgrid based on the consideration of users’ response to electricity price incentive demand under the multi-agent participation in the micro-grid.The first phase is to establish a complete information game interaction model between microgrid operators and consumers.Under the premise of protecting the interests of esales merchants,we set the consumer’s surplus as the optimization goal.As result of this optimization,not only can we get the optimal peak and valley time-sharing electricity prices strategy in the microgrid,but we obtain the corresponding consumers’ demand response curves under the incentive of electricity prices.The second phase is to simulate the game interaction between microgrid power investors and microgrid operators.With the goal of maximizing the interests of microgrid power investors,we can get the optimal configuration strategy for different distributed power capacity in the microgrid.The fourth chapter aims at the problem of island micro-grid capacity optimization,and establishes a capacity optimization model considering load demand management in the context of multi-scale uncertainty coupling.The model comprehensively considers multi-scale uncertainty coupling impact on long time scales.The random energy network theory is used to deal with power balance problems for source and load uncertainties.At short time scales,the uncertainty of source and charge prediction errors is considered at the power balance level We also consider the load demand management.By modeling the control for interruptible load and translatable load,it can be achieved that load characteristics are optimized,the costs reduce and the stability of the system enhance at the operation level.The dual layer optimization model is established to study and analyze from the aspect of power constraints and power balance,etc.We solve the model with the goal of minimizing the investment cost.The fifth chapter aims at the energy management and scheduling problem of the distributed multi-micro-grid system(MMG),using the distributed multi-agent system(MAS)to establish a multi-stage and multi-process energy management and dispatch control model including pre-scheduling,coordination optimization,rescheduling,willingness to participate analysis.The model is to maximize the personal income of microgrid and the comprehensive income of the regional operating entities so as to achieve game equilibrium,obtain the optimal energy scheduling and energy trading among entities in the microgrid and between the microgrid agents,where the overall regional interest is to maximize.At the same time,the model fully considers the unique performance of MG and its willingness to conduct power transactions with other MGs,and achieves distributed optimal control of MMG.