Voltage control-based ancillary service using thermostatically controlled loads

This paper discusses the possibility of providing voltage control-based ancillary services using thermostatically controlled loads (TCLs). The idea is to change the voltage at the point of common coupling in order to control power consumption of the TCLs through time. This allows to utilize the most common type of loads in the grid to provide ancillary services. These services differ from usual demand response strategies that operate on short to medium time scales. In this paper the authors propose a controller that regulate the power consumption by minimizing the power consumption error signal and by taking physical restrictions into account. Voltage restrictions arise due to the small window of voltage variability about the nominal value of the controlled voltage. In addition, capacitor bank switching interactions with motor and thermostatically controlled loads is discussed.