Study On Transient Stability Analysis Of Jiangxi Power Grid Based On New Energy Grid Connection

With the development of economy and society,the grid structure of Jiangxi Power Grid has been continuously enhanced and the load has increased year by year,which has brought difficulties to the stability of the power grid and the dispatching work.Especially in recent years,the capacity of the assembly equipment of Jiangxi New Energy Generator has increased significantly.Transient stability brings more severe challenges.When the system fails,the voltage drop may cause the new energy unit to be disconnected from the network,causing impact on the power system and even causing power outages.According to the annual report of Jiangxi Power Grid in recent years,some scenes are displayed.The unit has the risk of offgrid.It analyzes the new energy access situation of Jiangxi Power Grid in advance,checks its transient stability and studies the prevention and control measures for the off-grid unit to become an urgent demand of Jiangxi Power Grid.In view of the above problems,this paper firstly studies the power system transient stability discrimination method and the measures to improve the transient stability,and establishes the model discrimination method based on the extended equal area method(EEAC),and then relates to the new energy unit network.The model is developed to analyze the impact of wind power and photovoltaic grid-connected on the transient stability of the system.The power grid simulation model of Jiangxi Power Grid is established in the Power System Analysis Software Package(PSASP).Based on the main grid structure of Jiangxi Power Grid and the new energy development plan of Jiangxi Power Grid in the next two years,PSASP is used to build a doubly-fed wind turbine and photovoltaic battery model based on Jiangxi 2020 Fengping Power Grid,under heavy load,flat load and small load.The transient stability of new energy units connected to the grid of Jiangxi Power Grid is analyzed in detail under three load operation levels.The state and cause of the off-grid of the unit are analyzed statistically,and the power angle,voltage and frequency of the system under three load operating conditions are studied by taking the N-1 fault of the Jiujiang main transformer as an example.The research shows that the off-grid situation of Jiangxi Power Grid after the access of new energy units is roughly divided into three categories: the terminal voltage does not recover to 0.9 pu within 2s after the fault;after the N-1 fault occurs in the grid,the system oscillates,resulting in new energy units.The terminal voltage continuously oscillates;the terminal voltage drops rapidly below the unit's low voltage ride-through range(0.2 pu)after the system N-1 fails.Finally,for the off-grid unit and considering the actual situation of Jiangxi power grid operation,the measures of using static reactive power compensation device(SVC)to improve the stability of the system are proposed.The results show that SVC has obvious compensation effect for improving the first two types of conditions,but for the third In the case of off-network,SVC can not play the role of compensation,and the fundamental method to be solved should be based on the actual grid to propose specific measures.