Research On Hierarchical Flexible Power Supply Scheduling Of Pelagic Islands In Line With Island Energy And Resource Endowment

Traditionally,pelagic islands mainly rely on diesel generators for local power supply.This high-emission energy supply mode is not only costly,but more importantly,deviates from the trend of green and efficient energy supply and utilization advocated at present.In fact,the reserves of multi-form renewable energy such as wind,light,waves and currents in most pelagic islands and their adjacent regions are sufficient enough to meet the energy demand for the development.If the renewable generation potentials are explored according to resource endowments and energy supply networks are reasonably dispatched,it can not only significantly reduce the consumption of diesel generation and frequency of resource reinforcement from mainland,but also truly implement the development concept of "eco friendly" islands.With the increasing maturity of distributed new energy generation technology,the community rooftop photovoltaic power generation system installed by island residents will become one of the important forms of new energy development on pelagic islands.In order to reduce power supply costs,island microgrid operators who mainly relied on diesel generation would also become positive in the renewable energy development.It has enough motivation to install renewable generation units on the load center island and surrounding areas suitable for cable laying,and the generated power will be fed into the main power grid via the cable.Surrounding islands temporarily inconvenient to lay cables but rich in renewable energy reserves will also be considered for development,and new mobile energy storage such as Electric Storage Vessel(ESV)is used to collect and release electricity in an orderly manner.In the future,pelagic islands will form a hierarchical flexible power supply architecture,that is,residential communities-load center island microgrids-pelagic island microgrid group.How to operate,dispatch and manage this new power supply system,there exist still many theoretical and technical problems to be overcome and solved urgently.To this end,this thesis studies and explores some key problems including surplus energy consumption of the island photovoltaic building integrated community(PBIC),economic operation of the microgrid of renewable island,economic dispatching of island microgrid group considering ESV energy supply forms,and economic dispatching of the island microgrid group considering non-integer hour energy transmission characteristics.The main contents are included as follows:In terms of surplus energy consumption of the island PBIC,in response to the problem of the surplus photovoltaic power access to the grid at a lower price,first,a framework of water supply system participating in community power regulation is put forward.Then,a multi-time scale operation model of the community energy management system is discussed in regard to the flexible adjustment characteristics of water pumps and water tanks.On this basis,aiming at the lowest total electricity cost and smallest external exchange power fluctuation respectively,a day-ahead and intra-day two-stage energy management strategy of PBIC is proposed.Furthermore,this scheduling model is linearized as a classic mixed-integer linear programming(MILP)problem and solved efficiently.The simulation results show that the proposed energy management strategy can not only reduce the power consumption cost of property and residents,but also smooth the power exchange between community and island grid,and realize the mutual benefit of both parties.In terms of the microgrid operation of the load center island,firstly,according to the power-cost curve characteristics of diesel generators,an electricity utility decisionmaking method which can economically maintain the efficient operation of diesel generators is proposed.Then,combined with the renewable generation prediction power and the laws of randomness and volatility,a simulation scheme of net load power sequences which can fully reflect the dynamic characteristics of power supply and demand of island microgrid based on Monte Carlo sampling method is discussed.On this basis,aiming at the optimal operation economy of system,a day-ahead and intra-day two-stage scheduling model of pelagic island microgrid that considers the operation constraints of diesel generators,batteries and desalination equipment is established,and then is converted as a MILP problem using linearization technology and solved efficiently.Finally,typical examples are given to verify the superiority of the proposed scheduling strategy.In terms of economic dispatching of island microgrid group considering ESV energy supply forms,firstly,a novel power supply mode of microgrid group is discussed based on surrounding multiple-resource-rich island generation,ESV power supply and load center island consumption.Then,the impacts of environmental factors such as wind,light and ocean current on the power output of resource enriched islands,ESV sailing time and the energy gap of load center islands are analyzed.On this basis,by measuring the dynamic sailing time of ESV with reducing the scheduling step size and rounding method,the interisland energy supply model of ESV is established.Furthermore,aiming at minimizing the total operation cost of the system,a day-ahead and intra-day two-stage scheduling model of pelagic island microgrid group considering the operation constraints of common units is established.and a two-stage solution algorithm including pre-processing and simplified processing is proposed,and the optimization model is converted as a MILP problem for efficient solution.The simulation results demonstrate the feasibility and economics of the energy supply scheme for the pelagic island microgrid group taking into account the participation of ESV.In terms of economic dispatching of island microgrid group considering noninteger-hour energy transmission characteristics,firstly,based on the kinematics theory,the impacts of environmental factors including wind,ocean current,and wave on the ESV navigation are explored,so as to obtain a more accurate dynamic inter-island energy transmission time.Then,a dual unit combination collaborative decision-making method is proposed to characterize the behavior of ESV participating in the power regulation of island power grid.On this basis,aiming at the optimal economy of system operation,a day-ahead and intra-day two-stage scheduling model of pelagic island microgrid group is constructed.This model is transformed into a classic MILP problem using linearization techniques.The simulation results show that the scheduling strategy of pelagic island microgrid group based on dual unit commitment decision can not only reduce the burden of model solution,but also improve the economy of system operation.