Assessment of the impact of HVDC systems on power system restoration

This research investigates the role that High-Voltage Direct Current (HVDC) technology could play in power system restoration. Typically, the need of system restoration occurs following extreme events that lead to a blackout of a power system. In such cases, it is important to restore the system load as fast as possible. System operators mainly procure black-start services from conventional generating units, that progressively energise the transmission network, build a skeleton from their terminals to other generating units and, eventually, the load. This energisation is subject to several network and ramp-up constraints of the generating units. Past studies have formulated the restoration of the system as an optimisation problem that aims to minimise the load supply interruption. This work extends on the existing framework, by integrating HVDC systems into the formulation and applying it to support the restoration, either through transfer of power or by using the converters as black-start units. The proposed formulation accommodates various HVDC configurations that can arise. Simulation results on the IEEE 39-bus system reveal that significant benefits can be obtained by the utilisation of HVDC links during black-start.