Presented at B4 Poster Session, 2:30 PM Tuesday Konstantinos Plakas, Christos-Spyridon Karavas, Konstantinos Krommydas, Andreas Kurashvili, George Papaioannou, Panos Xenos Transmission line monitoring and power flow control in meshed networks have become major concerns for TSOs due to the heavily stressed electrical power systems caused by increased renewable energy penetration. Modular Synchronous Series Compensation (M-SSSC) technology can provide scalable, cost-effective solutions to network congestion issues by providing enhanced network operability and control. This paper explores the planning and deployment of M-SSSC devices on the Greek transmission network. The whole design, preparation, and installation of the M-SSSC system was completed within one year, proving the rapid deployability of this technology. Its modular nature provided the possibility to be sized optimally for the exact system’s needs, lowering the costs and environmental footprint of the solution by minimizing unnecessary use of equipment and space. Power flow studies and the analysis of real site test results validate the ability of M-SSSC to control power flows in real-time and deliver positive impacts on existing and forecast cross-border transfer capacity. This affects the grid's ability to bring renewables online, reduce network congestion, maximize cross-border infrastructure use, and ensure network security.