Automated Corrective Actions by VSC-HVDC-Systems: A Novel Remedial Action Scheme

The introduction of high voltage direct current (HVdc)-systems based on voltage source converters (VSC) within the ac transmission system enables new operational strategies. Fast VSC set-point adaptations in post-contingency scenarios can re-establish a secure state of the overall system. However, these corrective actions require a reliable activation and global coordination, especially of the HVdc-system and its dc voltage control. A comprehensive approach addressing these requirements is presented in this work. The approach is divided into three main modules. During online operation, critical contingency events are identified based on local measurements. An expansion of the local converter control enables an activation of suitable corrective actions to be pre-determined by a corrective security constrained optimal power flow.