A Modular Static Synchronous Series Compensator Offering Improved Scalability and Replicability Properties

The increasing share of renewable energy generation as well as the liberalization of the electricity markets has led to transmission congestion issues. Traditionally, congestion issues were dealt through grid expansion or upgrading existing transmission lines; these solutions, however, require significant lead time, large upfront investment costs and may be subject to environmental issues or societal opposition. Flexible AC Transmission Systems (FACTS) have been considered a promising solution for dealing with congestion problems and enhancing the stability of power systems. However, FACTS devices may need several years to design, manufacture and install, while it is not easy to relocate them when the needs of the power system are changed. These disadvantages have limited their wider use. In this context, a Modular Static Synchronous Series Compensator (M-SSSC) is presented, which consists of a novel FACTS device to deal with congestion issues that exhibits improved scalability and replicability properties. Overall, an innovative design approach is presented, and a detailed description is provided from the implementation and real-time operation of the M-SSSC in the Greek transmission system, as proof of concept. Finally, a scalability and replicability comparison is conducted with conventional FACTS devices and alternative solutions for mitigating congestion issues to showcase the superiority of the proposed design.