Privacy and optimality of distributed schemes for secondary frequency regulation in power networks

The increasing participation of local generation and controllable demand units within the power network motivates the use of distributed schemes for their control. Simultaneously, it raises two issues; achieving an optimal power allocation among these units, and securing the privacy of the generation/demand profiles. This study considers the problem of designing distributed optimality schemes that preserve the privacy of the generation and controllable demand units within the secondary frequency control timeframe. We propose a consensus scheme that includes the generation/demand profiles within its dynamics, providing guarantees that those cannot be inferred from the communicated signals, even when eavesdroppers possess knowledge of the underlying system dynamics. For the proposed scheme, we provide analytic stability and optimality guarantees and show that the secondary frequency control objectives are satisfied. The presented scheme is distributed, locally verifiable and applicable to arbitrary network topologies. Our analytic results are verified with simulations on a 9-bus system, where we demonstrate that the proposed scheme enables an optimal power allocation and preserves the privacy of the generation/demand and the stability of the power network.