| Environmental pollution and energy crisis are serious issues that confront the human society today.The energy sector probably brings about the most pollution and harmful emission.Therefore,the only way for the future energy industry is to be clean and low-carbon.The energy internet supports the two-way interaction of energy flows and information flow,in which the centralized and distributed energy systems are compatible.This compound form will improve the comprehensive utilization efficiency of energy and the accommodation proportion of renewable energy(RE).Besides,the performance of energy conservation and emission reduction and the development of diverse commercial formats can be boosted.To explore the trading modes and mechanisms for coordinating multiple energy types is a significant task that accelerates the practice of energy internet and the realization of carbon peaking and carbon neutrality goals.Meanwhile,the worth of trading energy is revealed.The deepen reform in electricity market and the opening-up in retail side provide a good opportunity for district integrated energy systems(IESs).A district IES is composed of distributed energy resources(DERs)based on microgrids(MGs)or micro energy grids(MEGs)physically.The various parks and communities in the cities and towns are becoming pilot districts,which have drawn much attention.In addition,the district IES provides a suitable platform for the diverse subjects to trade multiple energy objects in coupled markets.The thesis starts with the definition and classification of trading modes,followed by the key elements of market construction.The trading modes and mechanisms in district IESs are regarded as the principal lines.The operation and trading models of a single district IES and several district IESs in a coordinated pattern are studied respectively.It is suggested to adopt trading mechanisms and modes appropriately so as to blend them well and form a systematic research on the contents that the thesis investigated.The research will also provide theoretical and technical support for the implement of district multi-energy trading.(1)Trading modes and mechanisms design for coordinating multiple energy resources.Firstly,the definition and classification of trading modes are given.The distinction and progress of three modes are emphasized.In terms of the distribution network-leading mode,the microgrid and distribution network-coordinated mode,and the microgrid-autonomous mode,the key elements of market construction,the optimization models of market trading,the supporting technologies,and the typical application forms are discussed in order.Lastly,the directions of trading modes and their match with mechanisms are pointed out.Besides,the specific mechanisms employed in the following chapters are given.(2)Operation of a district integrated energy system based on a Stackelberg game approach.When a new district is installed with a park-level energy station,the building microgrid and park distribution network-coordinated mode is suitable.In this chapter,a dynamic pricing mechanism(only submitting quantities),a risk aversion mechanism,and an integrated demand response(IDR)mechanism employed in a single park IES are studied.Firstly,the energy and information flows of the district IES,and the proprietorial and operational rights of the devices are introduced.Then the mathematical model of a one-leader-multi-follower noncooperative game is elaborated.The relation between risk sources and risk bearers is clearly stated.The scenario theory is used to model the multiple uncertainties,and the conditional value at risk(CVa R)metric is adopted to measure the risks caused by the uncertainties.Additionally,the building prosumers(BPs)and the electric vehicle aggregator(EVA)participate in the pricebased and incentive-based IDR.Next,the existence and uniqueness of the Stackelberg equilibrium is demonstrated and a bisection-based distributed algorithm to obtain the equilibrium is introduced.Finally,the case study of a commercial district IES verifies the effectiveness of the algorithm and shows the economy and flexibility of the district operation.(3)Trading model of a district integrated energy system considering carbon emission.When a mature district lacks in a park-level energy station,the building microgrid and park distribution network-coordinated mode is also suitable.However,the trading strategy is different from the above.With respect to a single park IES,a competitive auction mechanism and a sharing mechanism for cooling,heating,electricity,and carbon are studied.Firstly,the rules in district multi-energy market and the interaction flows among players are given.When the district energy operator(DEO)organizes the internal multi-energy trading,the auction mechanism based on the demands of cooling,heating,electricity,and carbon is adopted(submitting both prices and quantities).The prices and quantities submitted by the prosumers are mathematically separated.Then the principle of a multi-leader-common-follower noncooperative game and the particle swarm optimization(PSO)to achieve the equilibrium of the nonlinear equilibrium program with equilibrium constraints(EPEC)are introduced.Lastly,the effectiveness of the algorithm is validated by the case study of a university IES.Besides,the energy sharing is realized and some unforeseen difficulties are solved.(4)Energy-sharing operation strategy of multi-district integrated energy systems considering carbon and renewable energy certificate(REC)trading.When the geographical range is extended from a single park to multiple parks,the park microgrid and city distribution network-coordinated mode is introduced.An energy sharing mechanism,a twosettlement mechanism,and an IDR mechanism are studied in the multi-district IES.Firstly,the structure of IES in one park and the setting of aid pipes among parks are given.In the operation model of multi-district IES participating in several markets,the scenario-based stochastic programming method is used to model the multiple uncertainties and the two-settlement mechanism is employed to calculate the uncertainties for the cost and benefit items.A more objective rule to allocate the benefits of renewable energy generation(REG)that are earned from carbon and REC markets is proposed.Moreover,the green index(GI)system is designed to evaluate the comprehensive performance in accommodating renewable energy and reducing carbon emission as for the multiple parks.Lastly,the modified IEEE 33-bus distribution system with radial heating and cooling networks is employed to analyze the economy,security,and eco-friendliness of multi-district market operation.The practicability of the methods,the rule,and the index proposed is verified via the city-level IES including four parks. |
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