| The integrated electricity-natural gas system can realize energy conversion,storage and redistribution,and has good development prospects and economic value.In recent years,with the large-scale integration of distributed wind power generation,the power-gas flow of the system shows strong random fluctuation,and the uncertainty of the operation of the integrated electricity-natural gas system increases.In this context,how to coordinate heterogeneous energy flows to achieve the optimal operation of integrated electricity-natural gas system under uncertain environments has become the focus of attention in the field of integrated energy.Therefore,based on the credibility theory,this paper studies the optimal power-gas flow of the integrated electricity-natural gas system with uncertain wind power.The specific research contents are as follows:Firstly,aiming at the integrated electricity-natural gas system with gas turbine,power-to-gas equipment,wind turbine and energy storage device,this paper constructs the integrated electricity-natural gas system framework on the basis of considering the coupling and complementary relationship of electric and gas heterogeneous energy,and analyzes the working principle of the energy equipment in the system,which provides a theoretical basis for the optimal power-gas flow calculation of the integrated electricity-natural gas system.Secondly,aiming at the problem that the power-gas flow uncertainty of the integrated electricity-natural gas system,from the perspective of risk aversion,this paper deduces the fuzzy chance constraints of gas turbine and power-to-gas equipment to stabilize the uncertain power fluctuation of wind power.On this basis,the optimal power-gas flow model of integrated electricity-natural gas system based on credibility theory is constructed.To solve the problem of nonlinear and complex constraints contained in the model,this paper uses the credibility measure theorem to derive the clear equivalence class of fuzzy chance constraints,and transforms the nonlinear Weymouth equation into a mixed integer second-order cone constraint.The simulation results verify that the proposed optimal power-gas flow model can effectively balance the risk and cost of the electricity-gas interconnection system and improve the consumption level of uncertain wind power.Finally,aiming at the problem that wind power uncertainty is transmitted to natural gas network through coupling equipment.this paper transforms the fuzzy chance constraints of gas turbine and power-to-gas equipment into natural gas constraints based on the gas-electricity energy conversion formula,and constructs the interval optimal power-gas flow model of the integrated electricity-natural gas system considering the coupling of electricity-gas uncertainty.According to the basic properties of interval matching and extreme value interval selection,the interval model is transformed into two conventional deterministic optimization problems with only deterministic variables.The example analysis shows that the proposed model can effectively avoid the risk of electricity-gas uncertainty coupling and improve the operation flexibility and economy of the electricity-gas interconnected system. |
