Application of a novel approach of resistive‐type superconducting fault current limiter with a fast protection system in multi‐terminal direct current network

The key obstacle in the realization of Multi-terminal HVDC (MTDC) grids is the lack of existing commercial protection that a device can withstand the DC fault. Although different HVDC circuit breaker technologies have been investigated and demonstrators tested by manufacturers, the innovation of such devices to ensure a reliable protection system has not been proven yet due to the maximum braking capability limitation especially in MTDC grids. To this, a combination of Superconducting Fault Current Limiter (SFCL) technology with a fast DC circuit breaker could bring a solution to this bottleneck. In this work, a new application of an accurate model of resistive-type SFCL (rSFCL) considering both the electrical and thermal behaviors is proposed to work together with a proactive hybrid DC circuit breaker (PHCB) to fulfill the whole system protection. The viability of the proposed approach is verified under a worst DC fault case-scenario that imposed in a five-terminal MTDC meshed grid. The numerical analysis and simulations are carried out using (EMTP-rv®) software, while the obtained results show how significantly the proposed rSFCL can reduce the fault current and enhance the breaking capability. Also, a positive interaction has been observed between the rSFCL and PHCB in terms of design sizing and operation performance.