Integration of an MMC-HVDC Link to the Existing LCC-HVDC Link in Balearic Islands Based on Grid-Following and Grid-Forming Operation

The decarbonization plans are leading to the decommissioning of conventional power plants, resulting in a deep transformation of power systems. Balearic Islands are not an exception and, in order to compensate this generation reduction and increase the security of supply, a second HVDC link is planned to interconnect the Balearic power system to the Spanish mainland. In this application paper, Modular Multilevel Converters (MMCs) have been assumed as the preferred technology for this HVDC link. A transient analysis has been presented to evaluate the system performance after the introduction of this new HVDC link. Grid-following and grid-forming control strategies have been implemented, comparing their impact on the system performance and stability. The transient events considered are the disconnections of the main synchronous generators of the islands and AC faults in several locations of the Balearic power system. A final case based on a penetration of 100% of converter-based resources has been also simulated to study the islanded operation of the MMC-HVDC link.