Impact of renewable generation on commutation failures in multiinfeed HVDC systems: a real case study

HVDC technology is a key driver for the integration of renewable energy sources (RES) in large transmission systems. However, the displacement of conventional thermoelectric power plants due to RES development can hinder safe operation of LCC-HVDC converters, especially during inverter operation, mainly due to the reduction of short circuit power on the ac network. These issues are exacerbated in small insulated networks with multi-infeed HVDC systems, such as the Sardinian one. Synthetic indexes such as MIIF, CFII and MIESCR, as well as time-domain simulations, are used to assess the robustness of the AC-DC system in presence of RES. Countermeasures such as converter control system improvements and installation of synchronous condensers are evaluated, aiming at a larger penetration of distributed generation.