Interruption Performance of Parallel DCCB in Bipolar VSC-HVDC Transmission Systems

With the continuous development of Voltage Source Converter-based High Voltage Direct Current systems, protection and fault isolation requirements have become increasingly stringent. The direct current circuit breaker has emerged as a critical component for ensuring HVDC grids’ safe and reliable operation. However, conventional single-breaker configurations are often insufficient in handling high fault currents. This study implements a parallel DCCB topology within a bipolar VSC-HVDC transmission system. Detailed time-domain simulations evaluate its interruption performance under both rated and extreme fault conditions. The results confirm that the proposed parallel structure enhances current-sharing capability and ensures successful fault isolation. This work demonstrates the feasibility of parallel DCCBs in practical HVDC protection schemes.