Coupling Degree Evaluation And Optimization Of Receiving-end Power Grid

Today,fossil energy is increasingly scarce.With the development of renewable energy,such as wind and solar,has gradually replaced non-renewable energy.In order to achieve the optimal allocation of resources across regions,it is necessary to take advantage of the UHVDC transmission technology.Therefore,the AC/DC hybrid system has become the development trend of the future grid structure.In hybrid AC/DC grids,there is a strong electrical coupling between AC and DC,and multiple DCs.The multi-circuit DC interaction is easy to cause the cascading failure.In order to prevent the above failure,the reactive power of the receiving-end system and the power response will be greatly affected.Therefore,it is important for the construction of AC/DC hybrid system to analysis the stability and evaluate of power flow.The reactive power compensation and the optimization of load have significant influence in distribution network.Confronted with th above challenges,this thesis will focus on the optimization of receiving-end grid.The research contents are as follows:Firstly,this thesis analyzes the operating characteristics of hybrid AC/DC system.The re-search is divided into grid active-frequency characteristics and reactive-voltage characteristics anal-ysis.The operating characteristics of the grid under fault are analyzed to evaluate different DC feeds for different systems.According to the degree of influence,this chapter selects the key feature of influencing factors,and constructs a multi-level evaluation system.Secondly,aiming at the reactive power compensation optimization strategy of the main grid side of the receiving grid,researching the line faults based on the topology theory and the traditional electrical interface to identify the weak lines of reactive power compensation under the grid fault,and then the fault network and line faults.Based on the median,a multi-objective function aiming at power quality and economic cost is constructed.Using NSGA and F scores to obtain the pareto frontier and select the optimal decision.The IEEE-39 is applied to verify and explore the work related to reactive power compensation under faults.Finally,in order to deal with the power shortage such as DC blocking,the optimization of the distribution grid load of the receiving-end grid should be strengthened.Confronted with the chal-lenge of large-scale electric vehicle access,this chapter will put forward the guidance of charging price setting.In this chapter,combine the load and charging data of station to develop the optimal charging and discharging model of the electric vehicle,and integrate the grid structure adjustment system to formulate the charging price strategy.