Market Designs For Electric Vehicle Energy Storage And Integrated Gas-electricity Systems Within The Energy Internet

China is accelerating the construction of a low-carbon and efficient modern energy system.The energy internet,with electric vehicles and gas-electric interconnection as an important component,will become an important carrier for this progress.Electric vehicles(EVs)not only have the direct advantage of reducing oil consumption,but also can provide considerable energy storage resources for the power grid under the support of various V2G(vehicle to grid)technologies.They can contribute extreme values as providing peak-shaving,system backup,and many other aspects.Under the prospect of large-scale penetration of EVs,the quantitative description of the interactive potential of the green transportation network and its strategy of participating in electricity market scheduling not only help to avoid the mismatch between the coupling process,but also effectively promote the social benefits of energy conservation and emission reduction.At the same time,natural gas,as the most realistic choice for the clean supply of energy,is being interconnected with the power system of different scales.The specific practices include regional multi energy systems(RMESs)and deep-coupled wide-area gas-electric networks by natural gas fired power plants(NGFPPs).The research on the multi-energy market mechanisms is of great significance for achieving reasonable pricing and trading,stimulating supply and demand response,and improving the overall efficiency of these markets.In response to the above requirements,this dissertation conducts specific research around the following four key elements.(1)Aiming at the desired quantitative evaluation of the interaction capability between EVs and the power grid,key parameters are examined,and analysis is explained with examples under different V2 G modes.The natural characteristics of EVs,the behavior characteristics of vehicle owners and the physical characteristics of EV supply equipment(EVSE)are classified and simulated firstly.Then it follows the different constraints for the immediate charging mode,the managed charging mode,and the managed charging/discharging mode.Examples of reducing the difference between the peak and valley loads in an estimated 2030 scenario in China show that grid load fluctuations can be suppressed by interactive management of large-scale EVs in a sustainable and effective way.(2)Considering the potential of V2 G interaction,aiming at the challenges of its application,e.g.,the large EV population but with small single capacity,EV mobility,etc.,an aggregated structure with EVSE as the carrier is proposed along with a strategy to implement accurate and rapid response.In the strategy,the convection equations are used to simulate the state of charge for batteries under charging and discharging states separately.These equations are solved by the discrete differential method for partial differential equations.Moreover,to track the target signal accurately,the model predictive control is combined with the strategy as well.Taking the frequency service performance score of the PJM electricity market in the U.S.for an example,simulations verify that the proposed strategy can enable large-scale EVs to participate in the frequency regulation quickly and accurately while various optimization targets such as reducing battery loss can also be considered according to actual needs.(3)Aiming at the establishment of multi-energy prices and market operations for RMESs,an internal multi energy market are proposed with the equilibrium mechanism considering the external electricity market.The independent system operator for an RMES is able to internally manage the internal market with fair bidding from units under different property rights.Meanwhile,it participates in the bidding process of the electricity market and the contract making in the natural gas market.The internal and external markets each form a set of mathematical programming with equilibrium constraints.A customized nested iterative method is applied to find the equilibrium.The effectiveness of the proposed market structure is verified by simulations.It is also proved that the penetration of RMESs stabilize the price fluctuations of the external electricity market.(4)Aiming at the problems of gas and electricity systems caused by the lack of synergy between these two markets,a natural gas market clearing model with time-varying locational marginal prices(LMPs)is proposed,and the equilibrium is solved with its coupled electricity market.Firstly,the experience and lessons of chain accidents under the rapid growth of NGFPPs in the U.S.are summarized.Examples include the difficulty and uncertainty of biddings by NGFPPs,and the chain accidents caused by the mismatch between the gas and electricity markets.It is suggested that an integrated mechanism for the natural gas market with LMPs may provide an operational basis for the implementation of demand response for natural gas loads,and ensure the economics and reliability of the bids by NGFPPs in the electricity market.The co-evolutionary algorithm is used to find the equilibrium of the coupled markets.The example is validated to the marginal gas price of the node,Simulations show that the proposed methodology could effectively form the gas LMPs,reduce the peak electricity LMPs and improve the market efficiency.