Protection of VSC-based HVDC Transmission Systems Requirements, Challenges and Recent Advancements

The recent technological advancements related to power-electronic converters and DC circuit breakers have led to significant opportunities for development of Voltage-Sourced Converter (VSC)-based HVDC transmission systems and specifically HVDC grids. However, protection of the highly advantageous VSC-based HVDC transmission systems is a major challenge that is still constraining a wider proliferation of such HVDC systems. The impacts of DC-side faults on the VSC-based HVDC system and the host AC grid highly depend on the utilized VSC technologies (e.g.: various MMC topologies) and the grid characteristics. This panel will focus on the requirements and challenges associated with protection of VSC-based HVDC transmission systems, considering the state-of-the-art converter, DC circuit breaker, and relay technologies as well as the AC and DC system grounding strategies. The protection aspects of a diverse range of systems such as, HVDC connected wind farms, HVDC connected to weak ac grids, and HVDC grids themselves, will be discussed and exemplified.