Research On Total Supplying Capability Problem Of City Transmission Network Based On Benders Decomposition

With the rapid development of economy and the rapid growth of urban load in China,urban power grid began to construct in the direction of higher voltage level.The 220 kV and above voltage transmission network undertakes the bridge role of connecting long-distance transmission network and urban high-voltage distribution network in urban power grid.It has both the operation characteristics of transmission network and the network structure of urban power grid.The calculation of total supply capability(TSC)of urban transmission network has more and more important research value,which provides important reference for the calculation of operation boundary,analysis of power supply adequacy,optimization of load distribution,location and capacity planning of future urban power grid,as well as future load growth planning.However,the calculation of TSC mostly focuses on the distribution network,and few studies on the TSC of the transmission network.Moreover,The study of the transmission network focuses on the calculation of the transmission capacity of the cross-section,and few studies on the overall TSC of the urban transmission network.There is a research gap in the calculation of the TSC of the urban transmission network.Firstly,this paper describes the operation characteristics of the transmission network,and at least static voltage stability should be considered in the transmission network.Therefore,based on the optimal power flow model considering voltage and phase angle constraints accurately,a TSC model of urban transmission network considering static voltage stability margin and N-1 static security constraints is proposed.Secondly,aiming at solving the above NP hard muti-constrained and non-linear optimization problem,Benders Decomposition algorithm is applied in this paper.The main problem is used to calculate TSC,and the sub-problems are used to verify the N-1 problem and static voltage stability.According to the potential relevance of the sub-problems,an improved iteration strategy is proposed to reduce the number of sub-problems to be calculated in a single cycle,improve the linearity and feedback the quality of Benders cut.Finally,this paper analyses the relationship between urban transmission and distribution network,including the topology,connection form and operation mode.The simplified load transfer capacity of distribution network can be decoupled and applied to the corrective control to improve the TSC of the stock grid.In this paper,the effectiveness of the proposed method,model and algorithm is verified by standard examples of different scales and an actual urban power grid.