Application and Design of Resistive SFCL in ±160 kV MMC-HVdc System

The modular multilevel converter (MMC) high voltage direct current transmission (HVdc) technology plays a great role on multilevel dc systems and large capacity transmission systems gradually. Therefore, the protection for the MMC-HVdc system becomes particularly important, for the impact acreage of de short faults is wider, and damage is more serious. In this paper, the MMC-HVdc system electromagnetic transient characteristics of fault are analyzed and the superconducting fault current limiter (SFCL) resistance model is established for a resistive SFCL (R-SFCL) during the short fault. The thermal-electrical process of R-SFCL limiting short current is calculated by iteration method. Then, an R-SFCL based on noninductive bifilar pancake is designed for a +/- 160 kV bipolar MMC-HVdc system. The validity of the theoretical calculation method and design scheme is justified by the simulation in software PSCAD. The results show that the response time of the R-SFCL based on noninductive bifilar pancake is 0.1 ms and the short circuit current suppression rate is 35%-50% in 3-8 ms after the dc short fault.