A flexible approach to on-site power filtering and supply backup using high capacity high temperature SMES for maximum equipment utility

With power systems subject to an ever-increasing variety of load types, power quality remains of concern to both utilities and consumers alike. Some of the most concerning issues to users of sensitive equipment include voltage sags, supply interruption and current harmonics. This paper describes a comprehensive power quality device that can be designed to compensate for harmonic load currents and mains voltage variations in a system, as well as providing mains failure backup for smaller critical system loads. The design process described integrates high capacity high temperature superconducting magnetic energy storage (SMES) technology with active power filter (APF) switching technology to achieve the power quality device. The sizing of higher capacity SMES devices to suit critical load power requirements in a system and the complete design philosophy that maximises the usefulness of the whole power conditioning system are both discussed in the paper.