Loads Control And Optimization In Smart Grid Based On Large-scale Of Aggregated Air Conditioners

As smart grid construction is executed rapidly,the marketization of power industry in the world is developing.It restructurs the generation,transmion and distribution enterprises and encourages electricity transactions.In order to promote the economy development,the interconnection of the national grid and the construction of the electricity market are the main targets of the power industry in China.As a part of anncilary service,frequency regulation is acting an important role in electricity markets,and has important effects on the stability of the power grid.Specially,the HVAC(heating,ventilation,and air conditioning)units have been widely applied in commercial buildings and residences.It becomes a good choice to provide frequency regulation service.This paper focused on the character of the loads,and studied the control strucures of them to serve for the grid.This paper has theoretic significances and application values,the main research results of this paper can be summarized as follows:Firstly,the thermal dynamic model and the aggregated model of HVAC units are introduced and the operation character is described.Two basic control strategies of aggregated HVAC units are then presented and the weekness and merits of them are compared.The load character is further discussed based on the comparsion.Secondly,a mode-switched control strategy of aggregated loads is proposed to serve for the frequency regulation.The basic idea of it is that the different control method should be utilized according to different system state.The frequency regulation problem and control framework are constructed.The optimal controller gain is searched by one-dimentional search algorithm based on historical data.A two-stage regulation method is designed to improve the control performance.Based on two switching indictors,three mode-switched strategies are tested and compared.Thirdly,a hybrid-clustered control stategy is presented to control the aggregated HVAC units.The loads are divided into two clusters,and each cluster chooses different control methods to regulate HVAC units.The over-charging and deep-discharging of the loads are avoided by a step rule.The multi-dimentional serach algorithm is applied to find the optimal parameters of the controller.The parallel and cascade control structures are established and the optimal allocations of the loads,the reference signal and the tracking error between the two clusters were obtained by the particle swarm optimization algorithm.The simulation results demonstrate that the hybrid control strategies can reduce the errors in frequency regulation.Finally,considering the setpoint regulation mode of the HVAC units in reality,the frequency regulation optimization model,which contains multiple variables,is formulated to control the power consumption of HVAC units by changing their respective setpoints.A mapping between the temperature setpoint variation and the on/off state of TCLs was established.Then the problem was transformed into a 0–1 nonlinear programming,which can be solved by the binary DMS-PSO-CLS algorithm.Simulation results demonstrate that the binary DMS-PSO-CLS algorithm is an efficient method to solve the optimization problem.It is promising to control the TCLs respectively to serve for the frequency regulation in power grid.