Innovative technology in the Moyle interconnector

Power-transmission by high voltage direct current (HVDC) technology has been in commercial use for more than 40 years. Even though the basic concept has remained unchanged during the past decades, many technological improvements have been developed increasing system reliability and availability. Several examples of such, innovative technology are implemented in the new HVDC interconnector between Northern Ireland and Scotland, the Moyle Interconnector, a dual monopole (2x250 MW) system connecting the transmission systems in Northern Ireland and Scotland. This paper focuses on the direct light triggered thyristors and the modular redundant control system at the heart of the modern converter stations. It also discusses the use of cables with integrated return conductors, combining the high-voltage and metallic return cables, into a co-axial design. Other new technologies as triple tuned AC harmonic filters and hybrid optical DC current measuring devices, which have already been discussed in other publications are only briefly mentioned.