Research On Decentralized Optimization For Multi-Area Interconnected Integrated Energy System

With the development of energy marketization reform and the distributed renewable power generation,the active participation of integrated energy systems and active terminal users is inevitable,and the future energy system will be multi-agent.Limited by the different management authority and the privacy of information,the decemtralized decisions-making is considered as the dominant decision-making model of interconnected multi-agent.From the perspectives of interconnection of multi-area and user’s side,the decentralized optimization method of integrated energy system is studied in this paper,and the main work is as follows:(1)The day-ahead operation method of multi-area integrated energy system with the interconnection of electricity and gas is studied.A robust model based on affine policy is adopted with consideration of renewable energy uncertainty.In view of the long time scale of day-ahead operation,the steady-state model of gas pipeline is adopted.Moreover,the linear approximation and convex-concave process method are employed.Then,the iterating-alternating direction multiplier method(I-ADMM)is used for decentralized optimization.Finally,an acceleration strategy is proposed.Simulation results demonstrate the effectiveness of the proposed method and its advantages in computation time.(2)The real-time operation method of multi-area integrated energy system is studied.Considering the short time scale of the real-time operation,the approximate dynamic model of gas pipeline and the tie-pipeline equation among area are adopted,and the two-stage robust model with more flexible adjustment is used.In terms of algorithm,the nested algorithm based on column-constraint generation and convex-concave process is used for equivalent transformation of model,and the improved I-ADMM algorithm is used for decentralized optimization.Finally,three acceleration strategies are proposed.Simulation analysis proves the convergence of the proposed algorithm,the robustness of the operation strategy and the effectiveness of the acceleration strategies.(3)From the perspective of user’s side interconnection,the decentralized energy transaction of integrated energy system is studied.The integrated energy servicer is introduced for a large number of users to participate in the transactions of integrated energy market.A game equilibrium model between the integrated energy market and the user’s side is built.In face of the problems of complex objective function and large number of users,the decentralized optimization of user’s side is achieved by inexact-ADMM.The equilibrium between integrated energy market and user’s side is obtained through iteration.Simulation results show that the proposed model and algorithm are effective.In conclusion,this paper proposes a new method for the decentralized optimization of energy system under multi-area interconnection and user-side scenarios,and the proposed solution method is expected to be applied in the multi-area integrated energy system and the energy transaction between users and integrated energy system.