The increasing penetration of renewable generation and other inverter-based resources (IBRs) is reducing system inertia, short-circuit strength, and voltage stability margins in modern power systems. Hybrid Synchronous Condenser Systems (H-SCS), which combine a Synchronous Condenser System (SCS) and a Static Synchronous Compensator (STATCOM) at a common point of coupling (PCC), provide an effective solution to these challenges. This paper presents operational experience from the Phoenix H-SCS installation in Scotland and describes further developments incorporated into the Eccles project.

Commissioned in 2020, Phoenix was the first full-scale deployment of H-SCS technology. The installation has demonstrated enhanced transmission capability, dynamic reactive power support, inertia contribution, and improved disturbance response, enabling at least 280 MW of additional renewable power transfer while strengthening network performance. Extensive live-grid trials validated coordinated SCS–STATCOM operation under a wide range of operating conditions and disturbances.

Building on these results, the Eccles project, scheduled for commissioning in 2027, introduces larger H-SCS units with flywheel-enhanced inertia, grid-forming (GFM) converter control, power oscillation damping (POD), and advanced parallel-operation capabilities. The paper highlights the technical benefits, operational performance, and continued evolution of H-SCS technology as a scalable solution for reliable integration of renewable generation and improved power system stability.