Power Network Planning Considering Natural Disasters And Plug-in Electric Vehicles And Assessment Of Development Demands

Rapid development of the smart grid with penetration of intermittent renewable energy and integration of flexible loads like electric vehicles has brought more and more uncertainties to the power system.In order to reduce the adverse effect,these uncertainties should be taken into consideration in the power system planning to ensure the security and the economy.At present,the transmission network planning mostly focuses on the uncertainties inside the power system rather than external natural disasters though natural disasters have a great impact on the power system.At the distribution level,integration of electric vehicles and adjustable loads play an important role in distribution planning and operation.It is of great significance that how to account for these essential elements in the progress of the distribution system planning.Given the background above,preliminary investigation is performed on relevant issues and the main focuses of this thesis are summarized as follows:(1)An overview of the modeling of different uncertainties and the power system planning and its solving methods.First,various uncertainties are summarized for the modeling.Subsequently,the basic planning model of the power system is analyzed from the three aspects of its organization.Finally,the solving methods are listed divided into three categories.(2)The modeling of transmission system planning considering natural disaster risk based on multiple scenarios.First,the main idea based on multiple scenarios is determined to account for two types of uncertainties.Then different sets of representative scenarios associated with those uncertainties are generated to check the security constraints and calculate the natural disaster risk.The particle swarm optimization(PSO)algorithm combined with hierarchical optimization is employed to solve the problem.Eventually,a modified 18-bus system is employed to show that appropriate trade-off should be made between the economy and the risk to obtain a comprehensive optimization results while fully considering the natural disaster risk.(3)The modeling of the coordinated planning for distribution systems and electric vehicles charging infrastructures considering shiftable loads.First,a method of siting and sizing two types of electric vehicles charging infrastructures is presented.The P-median model is employed for siting of fast charging stations to minimize the total charging service cost.Then shiftable loads are introduced to the modeling of the coordinated planning for distribution systems and electric vehicles charging infrastructures.Finally,a 54-bus sample distribution system is employed to demonstrate the proposed method.The results show that remarkable economic benefits can be achieved by implementing the coordinated planning method and shiftable loads can also contribute to the distribution system operation and reduce the distribution system construction investment indirectly.(4)A method of assessing development demands in county distribution systems.Firstly,the well-established Maslow’s theory is employed for dividing demand levels in a given county distribution system and five demand layers are partitioned.Next,the multilevel characteristic index set is then attained by combining the indices in the five layers.Then,the indices are regarded as characteristic quantities to represent development demands in different aspects of the county distribution system and used for clustering analysis of multiple county distribution systems to attain typical characteristics of different categories.Finally,actual data of 60 county distribution systems are employed to show that assessing development demands in county distribution systems can provide decision reference information for future investments and construction in county distribution systems.Finally,several conclusions are obtained based on the research outcomes,and directions for future research indicated.