Convex Decentralized Optimization Method Of Optimal Energy Flow And Game Strategy For Electricity-Gas Integrated Energy System

In the primary energy consumption structure of China,fossil energy has always occupied a dominant position,but with the depletion of fossil fuels and the increasing problem of environmental pollution,promoting energy transformation has become an important task of the energy revolution.The overall goal of building an integrated energy system is to optimize the energy structure on the supply side and coordinate and complement various energy sources on the demand side,thereby effectively improving the comprehensive energy utilization rate.Because natural gas has the characteristics of high heating value,easy storage,and low carbon emissions,the electricity-gas interconnection system that couples the power network and the natural gas network has gradually become a basic form under the integrated energy system.In order to study the optimal operation of electricity-gas energy system,this paper proposes a low-carbon dynamic optimal gas-power flow model with carbon trading.However,the dynamic characteristics of gas flow are remarkably slower than those of power flow,the space-time partial differential equations are used to accurately describe the dynamic gas flow.In addition,this model introduces a carbon trading mechanism for fully exploiting economic and low-carbon benefits of the integrated electricity and natural gas energy system.In order to achieve the decentralized optimization of gas-power interconnection network and obtain a highquality solution,two kinds of inner and outer-coordinated convex decentralized optimization methods are proposed.Under this framework,the outer layer based on a penalty convexconcave procedure(PCCP)transforms the non-convex dynamic gas flow into a second-order constraint programming and the inner layer solves each step of the outer PCCP iteration with Benders and ADMM.Finally,a calculation example tests the optimization performance of PCCP-Benders and PCCP-ADMM,while the operation effect with different carbon trading prices is investigated in detail.Then,this paper proposes an interactive equilibrium model of electricity-gas energy system and integrated load aggregators based on stackelberg game.Considering the formulation of energy prices in the next day,the electricity-gas distribution system maximizes its profit with solving the day-ahead optimal energy flow.Under the price mechanism,integrated load aggregators optimize the energy allocations independently base on the research of demand response in order to minimize the charging costs.In addition,second-order cone programming(SOCP)and penalty convex-concave procedure are used to deal with the non-convex functions of electricity-gas distribution system.The stackelberg game model is transformed into a single layer optimization problem by jointly using the Karush-Kuhn-Tucker(KKT)optimality condition as well as the duality theorem of linear programming.Therefore,the global optimal interaction equilibrium solution is obtained by solving a mixed integer second-order cone programming.