Predictability and Fairness in Load Aggregation and Operations of Virtual Power Plants
This addresses fairness and predictability issues in power grid operations for load aggregators and DER operators, presenting a novel theoretical guarantee.
The paper tackles the problem of ensuring predictability and fairness in regulating aggregate demand of distributed energy resources within virtual power plants, showing that traditional controllers like PI cannot guarantee this, but iISS controllers can under mild assumptions.
In power systems, one wishes to regulate the aggregate demand of an ensemble of distributed energy resources (DERs), such as controllable loads and battery energy storage systems. We suggest a notion of predictability and fairness, which suggests that the long-term averages of prices or incentives offered should be independent of the initial states of the operators of the DER, the aggregator, and the power grid. We show that this notion cannot be guaranteed with many traditional controllers used by the load aggregator, including the usual proportional-integral (PI) controller. We show that even considering the non-linearity of the alternating-current model, this notion of predictability and fairness can be guaranteed for incrementally input-to-state stable (iISS) controllers, under mild assumptions.