Robust distributed volt/var control of distribution systems

Volt/var control (VVC) is essential to achieve a reliable and efficient operation of modern and future distribution systems with high penetration of distributed energy resources (DERs). In real time operation, uncertainties cause by variations of loads and fluctuations of other system components may result in a deviation from the desired voltage profile. In this paper, we propose a robust distributed control framework to formally address these uncertainties. The objective of the proposed controller is to optimize the closed-loop performance with stability guarantee while optimally rejecting disturbances arising from uncertain loads and DERs. In the proposed scheme, the structural constraint due to the underlying communication network makes the controller synthesis problem nonconvex and hence difficult to solve in general. An effective convex approximation is proposed for any communication structure to address this issue. Case studies are presented to illustrate the contribution of the proposed robust distributed VVC control scheme.