Application study of superconducting fault current limiters in meshed HVDC grids protected by fast protection relays

Abstract

The complexity of DC side short circuit fault current interruption has been identified as a major drawback of realization of multi-terminal HVDC grids. Although application of superconducting fault current limiters (SFCLs) in protection of HVDC systems based on slow protective schemes has been studied in the literature, its application in meshed HVDC systems based on modern and fast protective schemes has not been investigated, yet. This paper scrutinizes the SFCL application in the meshed HVDC grids protected by the fast DC protective schemes and fast hybrid DC circuit breakers. The purpose of SFCL application is to reduce the current interruption requirement of the HVDC circuit breaker and size of its elements. This research analyzes the requirements of suitable SFCL considering the fault operation behaviors of local protective relays and the hybrid DC circuit breakers. The results show that the appropriated SFCL can reduce fault current peak, size of current limiting inductor and also fault identification time. The application of SFCL not only reduces the size of surge arrester in the hybrid DC circuit breaker, but also can significantly decrease the current stress on the hybrid DC circuit breaker.