Optimal Collaborative Planning And Operation Strategy Of Integrated Energy Systems With Power To Gas Technology

Compared with other primary sources of energy,natural gas has some advantages such as high efficient,clean and environmentally friendly features.With the development of natural gas exploitation technology,the costs of natural gas have declined,and the permeability in power generation industry tends to increase.On the other hand,due to the occurrence of the power to gas(P2G)technology,surplus renewable energy generation can be converted into methane,and then injected into a natural gas network for transportation and storage.Therefore,the coupling between an electrical power system and a natural gas system has been strengthened,and a closed-loop system with bidirectional energy flow is established and a so-called integrated energy system is formed.As the result,new problems and challenges have been introduced in the planning and operation of the integrated energy system,as the existing power network planning models normally overlook the impacts of natural gas or other energy systems.Given the above background,in this thesis some relevant research work is carried out and summarized as follows.1)A collaborative planning model of integrated electricity and natural gas energy systems based on improved Benders Decoupling is proposed.First,the steady-state models of natural gas system are elaborated,including the steady-state models of natural gas pipeline flow,natural gas pipeline storage,compressor and gas storage facility.Then,a collaborative planning model of integrated electricity and natural gas energy systems is formulated from the economic point of view under the premise of satisfying the safe,reliable and efficient operation of integrated electricity and natural gas energy systems.According to the mathematical model with mixed integer nonlinear characteristic,Benders Decoupling algorithm is used to optimize the problem.Finally,that compared with the existing independent planning between electrical power system and natural gas system,the proposed collaborative model of integrated electricity and natural gas energy systems has certain economic benefits,is illustrated by a numerical example of the coupling between a 54 nodal electrical power system and a 19 nodal natural gas system.2)A collaborative planning and operation strategy of integrated electricity,natural gas and heat energy systems based on energy center is proposed.First,energy center framework and coupling matrix modeling method are summarized.And the energy center modeling unit including combined heat and power(CHP)unit is formed,and the conversion and influence between electrical load and heat load is considered.On this basis,the steady-state model of multi energy center network energy flow composed of energy centers,P2G stations,traditional generating units and renewable energy units is formed.Then,a collaborative planning and operation model of integrated electricity,natural gas and heat energy systems based on energy center is formulated to determine optimal location and capacity of traditional generating units,CHP plants,gas-fired boilers,transmission lines and natural gas pipelines.Finally,an integrated electricity,natural gas and heat energy test systems with 9 nodal energy centers is formed to verify the effectiveness of collaborative planning and operation model from multiple scenarios.And that CHP unit is conductive to improve reliability and economy of integrated energy systems,and that it is more obvious to save costs when CHP unit is used in the lower natural gas price scenario are explained.3)The economic evaluation model of P2G technology in planning and operation of integrated energy systems is proposed.First,the basic principle and conversion process of P2G technology and the application scenarios of P2G technology in collaborative planning and operation of integrated energy systems are illustrated.Then,on the basis of the above chapter,an economic evaluation model of P2G technology in planning and operation of integrated energy systems is further formulated.Finally,a numerical example shows that it's hard to obtain economic benefits when electrical power system and natural gas system are coupled just by P2G station under the current technical and economic conditions.And it is beneficial to decrease costs and improve reliability of integrated energy systems when P2G station and CHP unit are applied jointly.And that P2G technology can effectively contribute to consuming surplus wind power output,reducing phenomenon of wind power curtailment and obtaining remarkable economic benefits especially in the condition of larger wind power installed capacity are demonstrated.Finally,the research work is summarized and future research prospects in this field are pointed out.