Research On Frequency Control In Regional Power Grid With New Energy Electric Vehicle

With the excessive exploitation of resources and the growing shortage of fossil fuels,a large number of renewable intermittent energy to the grid has brought abundant energy,but the stochastic volatility and generation forecast accuracy lead to load imbalance,thereby the harmful effects has brought new challenges.The role of electric vehicles as a switch between controllable load and distributed energy provides a solution with the frequency offset caused absorbing and discharging the power has the potential of serving the power grid frequency regulationby the new energy grid.The characteristics of the electric vehicle quickly,and the electric vehicle is also a kind of transportation tool,so it is necessary to consider the traffic attributes when participating in the power grid frequency regulation.Based on this,research work in this paper is described as follows:Firstly,the lithium iron phosphate batteries used in most of electric vehicles,a new model for charging and discharging of single cell was established.The charging and discharging characteristics of the battery are tested under different conditions,and the power adjustment model is also deduced when participating in the grid interaction;Further,it is put forward that the system framework of large scale electric vehicle participates in power grid frequency regulation,and establish electric vehicle two level frequency regulation architecture based on the hierarchical management control.Secondly,it is studied that the frequency regulation model of traditional units and the charging and discharging static characteristics of the electric vehicle,and the mathematical relationship is represented by the elliptic function between the charging and discharging of the electric vehicle and the state of charge,combining with the frequency control strategy of electric vehicle,according to the SOC value to determine the priority of charging and discharging.Finally it is built the model of single and interconnected regional electric vehicle participating in power system frequency regulation in MATLAB.The simulation results show that the electric vehicle can not only accelerate the response speed,and reduce the frequency deviation,but also reduce the reserve capacity of the traditional units.Finally,in this thesis it is analyzed the uncertainty factors affecting the charging and discharging behavior of urban electric vehicles,and pointed out that the four kinds of state transition characteristics of electric vehicles involving in the frequency modulation,and presented an intelligent charging and discharging management mode which can be converted the electric vehicle into the power grid in an orderly way,subsequently the temporal and spatial distribution characteristics of various types of electric vehicles are analyzed.Monte Carlo method is adopted to simulate the controllable load capacity of a controllable electric vehicle in a day,and only the controllable electric vehicle serving the power grid.It is established that the load frequency control model of V2G interconnection system based on the travel law of the traditional two area interconnected frequency regulation system and on the analysis of the V2G centralized equivalent model in a period of time.On the existing population and the number of electric vehicles in Changsha City,the scale of electric vehicles in 2020 is forecasted,and it is analyzed that the response of the electric vehicle in Changsha and the response of the two area interconnected system.