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Optimal Dispatch And Bidding Strategy Of Aggregators With High Penetration Level Of Distributed Energy Resources

Posted on:2020-07-12Degree:DoctorType:Dissertation
Country:ChinaCandidate:B S LiFull Text:PDF
GTID:1362330623963913Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
In recent years,the penetration level of distributed energy resources(DER)including distributed generation,energy storage system and price-elastic load in the power system constantly increases with the development of Smart Grid technology.DER can not only serve as renewable energy resource replacement but also provide variable ancillary services,which reinforces the economic and secure operation of the power system.DER,however,is often dispersedly located in the power grid with small individual capacity,resulting in difficulty in direct management by the Independent System Operator(ISO).Moreover,the inherent uncertainty,such as the volatility of wind and photovoltaic power generation,random charging and discharging behaviors of EV as well as the violation of demand response(DR)contracts adds to the management difficulty of DER.DER aggregators are therefore employed as an efficient way for the management of DER and the realization of its potential.Under the collective management of aggregators,a number of DERs can participate in the power market together as one entity.In this paper,uncertainty optimization,risk management,game theory,and data-driven approaches etc.are employed to study the optimal dispatch and aggregation of DER.Considering the uncertainties from both the DER and the market price,we focus on the optimal DR activation strategy,optimal bidding strategy of DER aggregator,cooperative and non-cooperative bidding strategy of multiple DER aggregators and the influence of DER on optimal system operation.We hope this paper contribute to the issues on improving the economic benefit of power system operation with DER penetration.The main contents and contributions of this paper can be summarized as follows.Considering the high-penetrated price-elastic load in the power system,DR is studied first in this paper.We propose an optimal DR dispatch strategy considering the locational marginal price(LMP)level of the energy consumer.Moreover,we propose a DR cost allocation method based on the cost-saving contribution coefficient.The method guarantees the economic benefits of consumers at different buses of the system,avoiding loss caused by DR dispatch by fair cost allocation.When multiple kinds of DERs exist in the power market,a DER aggregator is employed for the collective management.Considering both the DER and market price uncertainty,a two-stage stochastic model is built to optimize the bidding strategy of a DER aggregator in both day-ahead(DA)and real-time(RT)power markets.Conditional Value at Risk(CVaR)is used for risk management.The payoff and risk of the bidding strategy are analyzed based on Shapely value and the stand-alone contribution(SAC).The fair allocation of the payoff and risk among different DERs can protect the economic benefits of DER owners and serve as important information in the new DER aggregation.With the increasing penetration level of DER,when multiple DER aggregators exist in the power market,they are motivated to bid cooperatively for the increase of energy capacity scale and payoff.The surplus profit,however,is difficult to allocate.A robust bidding strategy model considering both DER and market price uncertainties is built for individual aggregators.Based on which,a cooperative bidding model of multiple aggregators is built.The non-linear objective function is linearized through the Taylor series and the model is solved as a mixed integer second-order cone programming(MISOCP)problem.Moreover,Aumann-Shapley theory is employed for the fair allocation of cooperative bidding payoff among all the aggregators.In a non-cooperative power market with multiple DER aggregators,a bi-level bidding strategy optimization model considering the uncertainties of both the DER and the competing bidding strategy is built for the designated aggregator.A data-driven approach is employed for the modeling of renewable energy uncertainty.Information Gap Decision Theory(IGDT)is employed for risk management,based on which the bidding strategy optimization of the designated aggregator is built as the upper level.Using data-driven approaches,the ambiguity uncertainty set of competing bidding strategy is built.And the market clearing model considering the uncertainty of competing bidding strategy is built as the lower level of the model.The DER aggregator can modify its bidding strategy model to maximize its payoff according to different power market conditions.Based on the modified bi-level model,the influence of DER aggregator on the power system operation including economic benefit,load level and environmental issues,etc.is studied quantitatively.Based on the characteristics and aggregation technique of DER,this paper focuses on the participation of DER in the power market.Considering the uncertainties from both the DER as well as the market price,and the influence of competing entities,the payoff maximization,risk management,payoff and risk allocation,concerning the optimal bidding strategy of the DER aggregator are studied.Moreover,the influence of DER aggregator on the economic and secure operation of the power system is studied.The methodology and models proposed in this paper contribute to the coordinate management and optimal dispatch of DER and DER aggregators.The system operators can refer to this paper according to specific DER type and scale in the power system.
Keywords/Search Tags:Distributed energy resource (DER), Demand response, Distributed energy resource aggregator, Coordinate dispatch, Bidding strategy, Risk contribution, Shapley value, Aumann-Shapley theory, Cooperative Game Theory, Data-driven approach
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