Using thermostatically controlled loads for the secondary control provision based on the modal method

The paper deals with providing ancillary services using thermostatically controlled loads, in particular electrical space heaters. Ancillary services, such as the secondary control, are aimed to maintain balance between production and consumption of the electricity. Developing concept of smart grids provides possibility to involve classical and advanced control methods for ancillary service provision. The aggregate consumption produced by thermostatically controlled loads is significant due to relatively big number of devices of this kind. The obtained results show that a large population of electrical space heaters can meet the requirements on the secondary control. The population model is based on the first order approximation of the equivalent thermal parameter model. The matrix form of the modal method is used for control system design. Since the modal method assumes using linear model, calculations of the controller parameter are based on a 1D bin state transition model, which is used for approximation of the population behavior. The main feature of the designed control system is that the temperature control and demand tracking are provided by the central controller simultaneously, whereas the standard approaches assumes the temperature to be controlled by the local thermostats.