Comparison of LCC/VSC-HVDC systems for Power/Frequency control in interconnected grids

The increasing complexity of interconnected power systems, combined with the growing integration of renewable energy sources, poses critical challenges for maintaining frequency stability. HVDC links represent a promising solution for enabling controlled power exchange and coordinated regulation between asynchronous grids. This paper aims to compare the two dominant HVDC technologies, Line Commutated Converter and Voltage Source Converter, with a particular focus on their ability to provide ancillary services to the power system. A MATLAB Simulink model, related to an asynchronous interconnected system where and HVDC system is involved, has been developed, and its control system has been implemented and simulated in order to verify the HVDC's capability to respond to various kinds of grid disturbances. Results show that the two HVDC technologies offer similar performance in terms of response time and frequency stability, even though the VSC system outperforms traditional LCC setups in terms of flexibility and general adaptability under varying grid conditions.