Abstract
Since the Electric Power Research Institute in the U.S.A. (EPRI) proposed the FACTS (Flexible AC Transmission System) in 1988, R&D activities of the FACTS are intensively pushed by the liberalization of the power delivery system in the U.S.A. and the Central Europe. Especially, the Unified Power Flow Controller (UPFC) that has been developed by the EPRI and Westinghouse is one of the most functional devices. However, the UPFC has several problems because of having complex transformers. For example, it not only generates comparatively big power losses into the transformers but also has to prevent the magnetic saturation of the transformers. As an effective solution, the Transformerless Reactive Series Compensator (TLRSC) has been proposed. Some basic operations have been already described in detail. However, the TLRSC is directly series-connected with transmission lines and the line current always flows through the TLRSC. Therefore, such special operations as a pre-charging operation, a start-up/shut-down operation and a continuous operation must be considered to realize the TLRSC. In this paper, firstly, a new configuration of the TLRSC with AC switches is proposed. Next, it is focused that the AC switches can carry out the special operations. Finally, it is verified that the new TLRSC doesn't need any transformer at all.
