Resistive SFCL Integrated Ultrafast DC Hybrid Circuit Breaker for Subsea HVDC Transmission Systems

High voltage direct current (HVdc) power transmission systems do not encounter any natural zero crossing unlike the ac systems, and hence, the dc circuit breakers employed should be fast-acting and reliable to ensure safe operation. Circuit breakers (CBs) that have fast response time with lower energy loss dissipation are required for subsea HVdc transmission systems. This article investigates the performance of various CB topologies, including ultrafast coupled inductor hybrid CB (CIHCB) topology without and with the integration of resistive-type superconducting fault current limiter (R-SFCL) for a 100-kV, 100-MW HVdc transmission systems. It is found that the addition of R-SFCL with 1.7-ms response time decreases the peak current through the breaker and, hence, the power dissipated in the CB during short-circuit fault conditions. Thus, the rating of CB can be significantly decreased with the proposed topology. Furthermore, a comparison of power loss in CIHCB with the existing topologies, such as mechanical CB, resonant CB, and HVdc-hybrid CB, are also presented in this article.