Inertial and Primary Frequency Control for MMC-based MTDC Systems

High penetration of renewable generation is challenging the traditional way system operators manage the grid. The resources required to control frequency and voltage, typically provided by large conventional synchronous generators, will be reduced as this technology is replaced by inverters-based generation. Inertial response and primary frequency regulation has been a permanent concern and subject of research as penetration of renewable generation increases. Voltage Source Converter (VSC) technology using Modular Multilevel Converter (MMC) topology presents a bright opportunity in power systems due to its improved performance and controllability advantages. This paper presents a method to emulate inertial and primary frequency response provided by synchronous generators (SGs) using an MMC-based MTDC system. The control system is tested on a MTDC link planned to be integrated to the Chilean grid for a scenario with high penetration of renewable generation. The results show that the control system allows the MTDC system to emulate inertial response and provide primary frequency regulation during generation outages.