Coordination of Loads for Ancillary Services With Fourier Domain Consumer QoS Constraints

Flexible loads can provide virtual energy storage (VES) by varying their demand around a baseline, just like charging and discharging a battery. Since the capacity of each load is small, the actions of many loads must be coordinated. We propose a decentralized coordination architecture to provide VES in the time-scale of minutes to hours. This is achieved through one-way broadcast from a balancing authority to all the loads, and local measurement of the grid frequency at each load. The local controller at a load uses a Model Predictive Control scheme which ensures consumers' quality of service by constraining the Fourier transforms of the control signal (the demand variation). The algorithm has provable convergence and robustness (to measurement noise) guarantees. Simulation studies with IEEE 39-bus system are provided to show its performance under various scenarios.