Demand Side Management using Model-Free Fuzzy Controller in a Direct Load Control Program

Integrating renewable resources such as wind and solar into the electric power systems introduces new challenges to the grid due to fast fluctuations which reduces the reliability of the system. Demand side management (DSM) is one method to cope with the uncertainty and variability of the generation. Direct load control of thermostatically controlled appliances can play a significant role for this purpose; however, the system operator requires a reliable estimation about the magnitude of the load and how much it can be shifted, in order to produce attainable desired aggregated load. The focus of this paper is on designing a model-free controller to follow the system operator's dispatch instructions. The main advantage of such controller is to eliminate the requirement for training or identifying the controllable loads' parameters; thus, it can be used as a plug & play component. The other advantage is that this system can dynamically cope with system changes. In this research, the controller changes the thermostat set points of the individual loads in a systematically manner so that the aggregated power consumptions of the loads would follow the desired aggregated load. To evaluate the performance of the proposed controller, a numerical simulator was developed, and the controller was applied over the simulation engine to follow arbitrary desired power profiles. It was observed that the system can follow the dispatch command in less than 10 minutes with a negligible steady state error (less than 5%).