Analysis on practical design of virtual-air-gap variable reactors for tieline reclosing in microgrid

In this paper, a systematic analysis is done on practical design of virtual-air-gap variable reactor (VAG-VR) devices. VAG-VR device is capable of reclosing tieline smoothly and improving power quality in microgrid during transient. Based on the theoretical fundamental of virtual-air-gap technology and experimental baseline tests, the characteristics and constraints of VAG-VR in practical design are analyzed and addressed to satisfy specified requirements in target system. The power dissipations in VAG-VR are analyzed as well, including the power loss in dc choppers made from SiC and GaN devices. The effectiveness of VAG-VR in tieline reclosing is demonstrated by simulation tests in a telecommunication power plant.