Market-based Control Of Thermostatically Controlled Loads

With the depletion of traditional energy and the deterioration of global ecological environment,developing renewable energy resources,such as wind power and photovoltaic power,and promoting energy transformation have been the common feature of global energy development tendency.In the scenario of high penetration of intermittent renewable energy resources,the power system requires more flexible resources to maintain power balance.Thermostatically control loads(TCLs)are one of the most promising demand side flexible resources.This paper takes market-based control(MBC)as the main control method and studies the control strategies of TCLs,e.g.air-conditioning loads(ACLs).Firstly,a market-based real-time control framework is proposed.The coordination of single type ACLs is taken as the starting point.For fixed-frequeny ACLs(FFAs),the basic demand curve and demand curve with offset are constructed,taking state of air temperature(SoT)and switching frequency into consideration.A feedback-based baseline load correction method is also put forward to to improve the robustness of the method.For inverter ACLs(IVAs),the demand curve is constructed aiming at achieving SoT-equality control.Active control and passive control scheme are put forward for applications with different requirements for control accuracy and communication burden.Simulations demonstrate the effectiveness of the proposed method in grid services,e.g.mitigating tie-line power fluctuation and frequency regulation services.The change rule of the state of ACLs under differnet demand curves is also studied in simulation cases.Then,a two-layer coordination control framework is proposed for fast frequency regulation services.In the upper layer,a virtual AGC generator is designed.It provides a simple interface as traditional AGC generators to the dispatch center;It implements control on several load aggregators(LAs)in sequence,which makes ACL cluster able to response to fast regulation signal with a long control cycle of single ACLs.In the lower layer,each LA collects the bidding information from ACLs and provides virtual storage model to the VGEN;It coordinates ACLs with the market-based control method to make ACL cluster track control target accurately.In addition,a regulation capacity estimation method which comprehensively considers several influence factors is put forward.Simulations demonstrate that the method has high accuracy and could gain high regulation revenues.Next,the MBC framework is extended to the unified coordination of heterogeneous ACLs.The demand curve construction principles to realize unified control are first put forward,including the unity in form of the curve,satisfaction of SoT and operational constraints and SoT-equality control.The demand curve of FFAs and IVAs are re-constructed acoording to the above principles.Simulations demonstrate that the method can achieve accurate trakcing performance and evenly allocate the target power among different types of ACLs.Besides,the effectiveness in scenarios of imperfect communication,model errors and realease control are evaluated in case studies.Finally,the control method is further extended into the unified coordination of generalized energy storages(GESs).A normalized general index,degree of satisfaction(DoS),is first introduced.The DoS of differnet GESs are then defined.The unified dynamic models of different GESs are established taking DoS as the state variable.Then,the general construction method of GESs’ demand curves is proposed,which is able to realize DoS-equality control.Based on the dynamic model and DoS-equality control feature,the aggregate dynamic model of a GES cluster is derived,which is used to establish the optimization model for GES cluster to participate in multiple markets.Simulations demonstrate the economic performance,tracking performance and the satisfaction of diversified energy demand of different GESs.