Planning And Design Of 220kV Dedicated Substation Access System For Refining And Chemical Project

With the rapid development of the national economy,The demand for electricity in large chemical companies is increasing,In order to meet the electricity needs of such enterprises,The establishment of dedicated substations in industrial enterprises has become a trend in power development.Dedicated variable access to the grid system is bound to affect the power flow distribution,node voltage,line load,etc.,and the power quality of other nodes will cause fluctuations.In order to meet the reliability of the refinery project and consider the economics of the dedicated variable access system,the planning and design of the dedicated variable access system must be scientifically and rigorously demonstrated.Based on the characteristics of the current 220kV grade grid operation in X City,this paper plans and designs the scheme of X-city 220kV grid for large-scale refinery enterprises in X city.Firstly,the prediction model of combined regression-BP neural network is first used for X city.The total amount of electric power load is predicted,and then the load is assigned to each substation node by the "land use type load density index method",and the power grid is preliminarily planned and power supply arranged according to the electric load forecast.After determining the network equivalent parameters,the PowerWorld simulator software is used to build the power grid simulation model,and the power flow calculation and stability analysis of the dedicated variable access grid are performed.The grid equipment and operational data and load history parameters brought into the model are all X city actual.Historical data,the simulation results are more suitable for the actual grid operation.The analysis methods and steps used are:first analyze the steady-state operation of the power grid in the dedicated variable access system,and under extreme operating conditions(saturated dry season)The power grid model performs n-1,n-1-1 fault analysis power flow simulation,selects the equipment for different schemes and selects the optimal wiring scheme based on economic analysis.Finally,the preferred scheme is connected to the X city power grid for verification.It shows that the dedicated variable access system scheme designed in this paper has good power supply reliability and economy.