Research On Optimal Scheduling Model And Method For Aggregated Prosumers Based On Transactive Energy Mechanism

In recent years,with the increasing penetration of distributed energy resources(DERs),the deregulation of power industry and the deep integration of energy and Internet,great changes have taken place in energy structure and power system operation mode.In view of a series of problems such as strong intermittence,strong uncertainty,strong volatility of high proportional distributed energy resources,as well as insufficient capacity of distribution network in early planning phase,prosumers actively managing their consumption,production and storage of energy in the demand side will play an increasingly important role in the future power system operation.Subsequently,in the electricity market operation,how to take full advantage of the flexibility available from prosumers' resources has attracted extensive attention in academia.Transactive energy(TE)as a power system mechanism based on market trading rules that allows the dynamic balance of supply and demand across the entire electrical infrastructure using value as a key operational parameter through decentralized control strategy,which has a broad development prospect for supporting prosumers to participate in the market-based operation of power system.However,the prosumers' framework based TE mechanism involves multi-agent operations in different levels.Since these agents(users and operators,etc)have different functions and responsibilities,their scheduling strategies are diverse,their models are complex and it is difficult to solve their problems.Therefore,how to integrate the optimal scheduling model of aggregated prosumers with the operation frameworkof TE and solve it effectively are urgent problems to be solved.In view of the above challenges and problems,This study focuses on the analysis of prosumers' basic characteristics and classification,and summarizes the representative operation architecture,key technologies and existing problems.Furtherly,focusing on the hot issues such as optimal scheduling strategy,model and solution method of prosumers optimization problems,privacy information of prosumers,distribution network line overloading,etc.,the optimal scheduling model and method of aggregated prosumers under different representative operating scenarios supported by TE mechanism are studied.The specific research contents are as follows:(1)The research on the optimization operation of prosumers supported by TE mechanism is reviewed.The types and basic characteristics of prosumers,as well as the representative operation frameworks are analyzed and summarized.The functions and responsibilities of different operators are clarified.Finally,we summarizes the critical technology and existing problems for the optimal optimization of prosumers and point out the significant research direction in the future.(2)The roles and functions of community operators supplying electricity to residential communities is described,in the context of electricity market reform where one of objectives is to separate distribution company operation and electricity retailer operation.A two-stage aggregation and distribution operation framework of TE where the community operator participates in the electricity market on behalf of aggregated intelligent building prosumers is proposed.Aiming at the residential communities consisting of multiple intelligent building prosumers comprising photovoltaic(PV),energy storage systems(ESS),electric vehicles(EV)and thermostatic loads,a power aggregation model considering power sharing is established.On this basis,a day-ahead optimal scheduling strategy can meet the power demand of users and minimize the cost of each building prosumer is proposed.After the event,considering influence of transformer life,Shapley value is used to solve unfair allocation of benefits among the prosumers due to power limitation of distribution transformers.(3)The operation framework of TE is proposed for aggregated small and medium-sized prosumers in the distribution network.Based on the iterative distribution locational marginal price(iDLMP),the optimal scheduling model of the self-organizing prosumers is established.On the one hand,based on Lagrange duality decomposition principle,distribution system operator(DSO)adopts subgradient method to determine clearing price to guide the prosumers and avoids the line overloading.On the other hand,considering the nonlinear constraints of the energy storage resource and the prosumer's dual role as a producer and as a consumer,we convexify an optimization scheduling model of the prosumer under some reasonable conditions.In the simulation analysis,the effectiveness of the iDLMP is verified by comparing with the traditional centralized distribution locational marginal price clearing model.In addition,the numerical results show that the proposed method can effectively alleviate congestion and achieve local energy sharing in distribution grid,respecting prosumers' economical interests and privacy information.(4)To improve low efficiency in solving the optimal scheduling model with high-dimensional decision variables,aggregated EVs model and heating ventilating and air conditionings(HVACs)model as prosumers' typical resources with time coupling characteristics needs dimensionality reduction.Considering the physical characteristics of equipments,the behaviors of occupants and environmental factors,a generalized virtual battery model(VB)is established for characterizing the flexibilitiy using an extreme energy circumstance method.On this basis,a day-ahead optimal scheduling model is developed for the integrated resources to participate in the wholesale market.The numerical results show that the day-ahead optimal schedule based on generalized VB model can coordinate the energy and reserve provision.In addition,the proposed model is verified by simulation,and its superiority in terms of computational efficiency and information security is analyzed.(5)Based on the deterministic generalized VB model proposed in(4),we introduce a VB model with robust boundary to describe aggregated large-scale prosumers' flexibility under uncertainty.Then,assuming price-responsive feature of prosumers,we employ iDLMP proposed in(3)to determine the prosumers'schedule for energy and spinning reserve provision with the purpose of preventing network congestion.Case studies are performed on a benchmark IEEE 33 bus system and show that the proposed method can effectively alleviate two-way overloading line in distribution grid,respecting prosumers' economical interests and private information.In addition,we also discuss and analyze the operation principle of time-varying and non time-varying resources responding to iDLMP method,and prove that the proposed solution method of the chance constraints optimization based on generalized VB model is suitable for the prosumer's optimization with high dimensional decision variables under uncertainty.