Research On The Operation Optimization Of The Integrated Energy System Considering Water-Energy Nexus

In recent years,with the continuous growth of the proportion of renewable energy installed and the improvement of heterogeneous energy conversion equipment technology,the interdependence between heterogeneous energy systems such as electricity,natural gas and heating system is increasingly strengthened,and the integrated energy system has attracted the attention of academia and industry.Water is not only one of the most necessary substances in the process of energy production and conversion,but also as a medium to realize the deep coupling between water distribution network and integrated energy system.It should be pointed out that the price and abundance of water resources will directly affect the operation efficiency of the integrated energy system.Therefore,it is urgent to explore the interdependence between the water distribution network and the integrated energy system and optimize the coordinated operation method.In this paper,an operation optimization model of the integrated energy system considering the water-energy nexus is proposed to explore the interdependence between the integrated energy system and the water distribution network.The main work is as follows:(1)From the perspective of multi-energy flow,the energy interaction between the comprehensive energy system and the water distribution system and the interdependence in operation optimization are explored,with the consideration of the power transmission system,gas transmission system,heating system and water distribution system.At the same time,a variety of coupling components,such as power-to-gas units,cogeneration units,water pumps and energy storages are also be considered,which can explore the energy flow interaction and its impact on the flexibility of the integrated energy system considering the water-energy nexus.(2)Based on the operation optimization model of integrated energy system considering water-energy nexus,a two-stage robust optimization model of the integrated energy system is proposed.The mixed integer second-order conical relaxation model is combined with the penalty convex-concave procedure to transform the difficult mixed integer nonlinear problem into a mixed integer second-order cone programming which is tractable,and a higher quality feasible solution is obtained by tightening.At the same time,by embedding the penalty convex-concave procedure into the traditional column and constraint generation algorithm,a two-stage robust optimization model suitable for the water-energy coupling relationship is proposed.The validity and applicability of the method are verified by tests.(3)The multi-objective optimization model of the integrated energy system considering the water-energy nexus is established,considering the multi-objective operation objectives of the integrated energy system and the target conflict scenario.Further,chance constrained method is used to describe and deal with uncertainties of renewable energy output and multiple load demand uncertainties in the integrated energy system considering water-energy nexus.The probability density distribution of wind power generation is fitted by Gaussian mixture model,and the probability density distribution of wind power generation is transformed from the intractable chance constraints to the solveable constraints.By means of Nash bargaining,a fair compromise is reached between multiple conflicting objectives,and the nonlinear and non-convex constraints of the model are dealt with by combining relaxation method and penalty convex-concave procedure.In conclusion,this paper proposes a new direction for the coordinated and optimized operation of energy and water resources,and this method has a guiding significance for the future construction of an intelligent and integrated social comprehensive energy and resources network.