Research On Thermostatically Controlled Flexible Loads Optimal Control Strategy For Active Distribution Network Orienting Smart Buildings

As a demand response(DR)resource,thermostatically controlled loads(TCLs)can response the power fluctuations of power grid caused by renewable energy and load activities by means of its good thermal energy storage characteristic and slow-varying thermal inertia.It is considered to be an important participant of the DR mechanism.The reasonable optimization control strategy is the key to fully utilize the TCLs scheduling potential and promote the flexible interaction between the demand side and.the grid side.This thesis systematically studies the optimal control strategy of TCLs from the controlled dynamics of TCLs population,the optimal aggregated control of heterogeneous TCLs and the optimal control of TCLs participating in grid auxiliary services.For the study of TCLs population controlled dynamics,it is difficult for heterogeneous TCLs population to evaluate its schedulable state by means of unified operation index or statistical state transition probabilities.For this issue,first,from the perspective of time,a unified quantitative indicator of the controlled tendency of heterogeneous TCLs is proposed according to the relative time when the TCLs reach the upper and lower limits of the controlled temperature dead zone from the current state.Further,Considering the controllability and controlled tendency of the TCL comprehensively,the TCLs population is divided according to the principle of maintaining the load state diversity and avoiding high switching rate and an available scheduling capacity assessment model for TCLs is established accordingly.Finally,the importance of the proposed transient controllability index to the assessment of TCLs schedulable state is verified by simulation.In terms of the optimal aggregated control for heterogeneous TCLs,aggregating TCLs based on clustering methods neglects the coupling of diverse thermal parameters with scattered geographical location of controlled TCLs,will increase the difficulty of control implementation and decrease scalability and availability of demand side scheduling potential.For this issue,a hierarchical control framework to aggregate TCLs in unit of building is proposed.Based on the proposed hierarchical framework,a state transition interval matching(STIM)control strategy is proposed at lower layer from time perspective to coordinate the scheduling flexibility of heterogeneous TCLs.The proposed STIM strategy realizes unified control of heterogeneous TCLs in one building,which could enhance the control accuracy and availability of TCLs scheduling potential.At high layer,from multi-agent system perspective,a distributed pinning control strategy in the consensus framework.The proposed pinning control coordinates the scheduling capacities provided by different buildings in a sparse communication network,which could enhance the control stability scalability of TCLs' participation in DR service.In terms of the optimal control of TCLs participating in grid auxiliary services,for the influence of compressor locking effect on TCLs controllability and TCLs population schedulable capacity,the response characteristic of controlled TCLs is analyzed first.It is derived that TCLs are not suitable for responding to continuously and violently changing scheduling control signals,which will greatly reduce its load flexibility.Based on the analysis of the response characteristic,a coordinated control model based on empirical mode decomposition(EMD)is proposed to instruct TCLs and the energy storage for smoothing the output fluctuation of renewable energy in the distribution network.Through the EMD algorithm,the scheduling operation mode suitable for TCLs is selected to avoid the concentration of TCLs uncontrollable in the load population.The reliability and stability of TCLs in participating in grid optimization operation is improved.