Restoration Resource Allocation And Decision Optimization Of Coupled Transmission And Distribution System

In recent years,the frequent occurrence of extreme weather events has brought challenges to the safe and stable operation of the power system.With the development of large capacity renewable energy generation technology and the gradual formation of AC-DC hybrid power grid,the network topology and dynamic characteristics of modern power system become more and more complex.If the local fault occurs,the chain reaction may occur,which eventually leads to the occurrence of large-scale blackout.As a high risk small probability event,once the blackout occurs,it will seriously affect the social stability and economic development.Thus,it is necessary to develop a complete emergency plan and scientific restoration plan for the possible blackout.Under the new situation of power grid,the large number of distributed generators increment and the wide application of demand side management make the traditional passive distribution network gradually change to the active distribution network with more flexible resources.Thus,in order to improve the efficiency of power system restoration after a blackout,it is necessary to carry out research on the coordinated restoration between the transmission and distribution systems.Based on the development direction of modern power system,and based on the extensive reference and learning of existing scientific achievements,aiming at the problem of restoration resource allocation of transmission and distribution system and the stage of load restoration after a blackout,this paper makes a more in-depth study on the restoration resource optimization of transmission and distribution system,the decision-making of coordinated restoration of transmission and distribution system and the dynamic decision-making of multi-step restoration taking the active distribution network into account.The research of this paper includes resource allocation optimization,multi-agent dynamic game method,decoupling mechanism,decentralized optimization framework and method,multi-step dynamic optimization algorithm and so on.The main research work of this paper is as follows.(1)In this paper,a strategy of resource allocation for transmission and distribution system restoration is proposed.By considering natural disasters as a rational virtual game player,together with power grid planners and black start units planners,a framework of coordinated transmission and distribution system natural disaster prevention based on multi-agent defender defender defender(D-A-D)dynamic game is established to realize the effective defense of power system against natural disasters.A case is given to show the process of multi-agent D-A-D dynamic game and the advantages of this method.The proposed method is applied to a practical case,and it is proved that the effect of multi-agent D-A-D dynamic game is better than that of traditional resource allocation-method.(2)An optimization method of coordinated restoration of transmission and distribution system is proposed.The coupled transmission and distribution network is decoupled by using the analysis target cascading method,and the decentralized optimization model of coordinated restoration of transmission and distribution is obtained.The 0-1 binary variable in the model is relaxed to ensure the efficiency of solution and narrow the optimization gap of calculation.The case shows that the decentralized optimization method based on the analysis target cascading can significantly improve the calculation efficiency and accelerate the load restoration process.(3)A dynamic decision-making method of coupled transmission and distribution system restoration is proposed.Considering the dynamic decision-making problem of transmission and distribution system restoration,a multi-step load restoration optimization model is established,which takes the future step restoration state into account,and makes full use of the real-time updated grid topology data to achieve the optimal restoration in a longer time domain.The case shows the process of multi-step load restoration optimization and the advantages of the method,and the method is applied to the actual case,which proves that the efficiency of multi-step load restoration optimization is higher than the traditional single-step load restoration optimization method.