Optimized Virtual Inertia Control For Frequency Regulation At Lcc-Hvdc Terminals Using Converter-Interfaced Synchronous Condenser

Line Commutated Converter (LCC)-based High Voltage Direct Current (HVdc) systems connected to weak ac networks face significant challenges in maintaining voltage and frequency stability. While synchronous condensers (SCs) provide reactive power and inertia support, their energy exchange is limited, and their voltage regulation response is slow. This paper employs a proposed SC configuration, called "Back-to-Back Synchronous Condenser" (BtB-SC), which interfaces the SC with the ac network via reconfigurable back-to-back (BtB) voltage source converters (VSCs). This setup dynamically adjusts the system’s apparent inertia and enhances damping, offering superior frequency and voltage regulation compared to standalone SCs. The BtB-SC’s controller parameters are optimized using non-linear optimization techniques to achieve rapid post-disturbance recovery. Electromagnetic Transient (EMT) simulations validate the system’s effectiveness, demonstrating significant improvements in inertia, damping, and overall grid stability for weak LCC-HVdc systems.