CONSTRAINED DISCRETE PREDICTIVELY CONTROLLED DISTRIBUTED ENERGY STORAGE EVALUATION IN A MULTI-BUS SYSTEM

摘要

The emergence of smart grids allows a novel network structure with the deployment of distributed energy storage systems (D-ESS). These storage devices act as viable alternatives to fix supply-demand mismatches, especially with ample penetrations of renewable power systems. We report the exploratory evaluation of distributed energy storage along machine load buses in a hybrid system. Two storage technologies, i.e., superconducting magnetic energy storage (SMES) and flywheel energy storage (FES), are considered separately in this paper, by virtue of their high power densities, swift discharge-charge schedules and expeditious time response. Detailed models of SMES and FES are developed, based on the generic P-Q control scheme of energy storage systems (ESS), besides capturing the DC link dynamics along their grid side converters. A constrained discrete predictive control (CDPC) strategy is adopted in regulating the active power trajectories of the energy storage. Bus frequency and voltage controllers translate the corresponding mismatches into reference power (P-Q) commands. Extensive stability strengthening apropos frequency regulation, oscillation damping, power smoothing and voltage ride through and control is acquired when the system is tested against an intense short circuit. All mathematical analysis and simulations demonstrate that the placement of D-ESS along the generator buses gives better dynamic system performance than load bus-oriented D-ESS deployment.