A Primary System Design Of The Power Transmission System Of 220kV Yanguan Town

With the development of the economic of Xingan,the power supply capacity of the powe r grid has been unable to meet the demand of users.So,A new 220kV Xingan substation are needed.Therefore,we plans to build 220 kV Xingan station,to improve the reliability of Xingan power grid,to reduce the pressure on the grid power supply and ensure the safe and stable operation of Xingan power grid,promote the rapid development of county economy.In this paper,the design and feasibility verification of the system are carried out according to the relevant standards.The main tasks are:1.On the basis of fully analyzing the economic development of Xingan county,the powe r load of Xingan county predicted by using the annual growth rate method and large user method.Using load forecasting result and local power supply construction to calculate the balances of electric power and energy,the necessity of the transmission and transformation project of 220kV Yanguan Town is proved.2.Based on the power grid planning and substation and line overview,this paper present-ed three schemes of access system for the 220kV Yanguan Town transmission and transformation project,and compared in terms of technical and economical of three schemes,and finally chosed the optimal scheme.Firstly,using the BPA power flow calculation software to calculate the power flow of the wet season and dry season in 2018,2020 and 2025 Years and analysis of different modes of access system on voltage and the influence of network loss and so on.Secondly,considering the influence of the wind turbine output for grid power flow,calculated the power flow of the wind turbines shutdown and 20%output of the wind generator,evaluatd the reasonability of the power flow distribution and voltage level of different access system scheme.Thirdly,calculated the operation conditi-on of the power grid under special operation mode and fault flow,and analyzed the adaptability under different access modes.Finally,the optimal system access scheme is determined through comparison of technology and economy.3.The construction scale and power supply scope of substation project are determined:the final size of transformer of the 220kV Xingan substation is 3×180WVA.This phase of the project is 1 x 180MVA.The final stage of 220kV busis designed as double busbar single section wiring mode,this period is double bus connection,the final size of 10 lines,7 lines to this period.110kV voltage grade,double busbar connection,the final size of 14 lines,5 lines to this period.The final phase of 1 OkV is to use single bus double section three stage bus connection,this period is single bus connection,the final size of 30 lines,10 lines to this period.neutral point grounding mode:220kV and 110kV voltage grade for main transformer neutral point directly grounding;10kV voltage grade is not grounded.In this paper,the necessity of engineering is proved using the balances of electric power and energy.The optimal scheme of substation access system is determined from the economy,the rationality,the power supply reliability,the implementation difficulty degree,the development adaptability of the access scheme.To some extent,The project of 220kV Yanguan Town solved the development planning problems of the Xingan power grid and promoted the further development of county economy.