The Impact of Point-To-Point VSC-HVDC Protection on Short-Term AC System Voltage

Whilst point-to-point HVDC systems are presently protected from DC-side faults using circuit breakers at the AC-side of the converter stations, converters are unable to provide reactive power support to the AC system during the fault clearance. Implementing DC circuit breakers within the HVDC system could result in several benefits, including the near- continuous provision of reactive power to the AC systems. This paper compares HVDC system protection sequences using AC- side and DC-side protection, and evaluates the impact of these protection strategies on the AC voltage under varying AC-system configurations and varying power flow conditions.