Scheduling and Provision of Secondary Frequency Reserves by Aggregations of Commercial Buildings

Due to thermal inertia, commercial buildings can provide power system frequency reserves with the heating, ventilation and air-conditioning (HVAC) systems. In this paper, we follow up on a recently proposed framework for scheduling and provision of secondary frequency control (SFC) reserves within a building aggregation. We extend this framework with a new reserve scheduling formulation, which is based on a combination of robust and stochastic optimization, to allocate reserve capacities among buildings. The HVAC system setpoints are determined by a model predictive controller, the frequency signal is tracked by heat pump (HP) control with virtually no occupant discomfort, and the tracking quality is evaluated using a dynamic HP model. In simulations, we consider an aggregation of typical Swiss office buildings and compare the robust and stochastic reserve scheduling approaches in terms of performance and complexity. Using the framework, we demonstrate the importance of energy-constrained SFC signals and asymmetric reserves with hourly resolution, and we investigate the sensitivity of reserves on the comfort zone's width, capacity payments, and HP constraints. Finally, we show that commercial buildings can track SFC signals well and substitute generators in SFC.