Multiport Current-Limiting Hybrid DC Circuit Breaker for MTdc Grids

Abstract

The coordination configuration of current-limiting inductors (CLIs) and hybrid dc circuit breakers (HCBs) is currently the most commonly used fault handling method to ensure fault ride-through of multi-terminal dc (MTdc) grids after the dc-side fault occurs. However, the high cost of HCB limits its large-scale application. In addition, the installation of the large CLIs will adversely affect the HCB performance, such as extending the fault current interruption time and increasing the energy dissipation pressure of the arrester. To solve these problems, a multiport current-limiting hybrid dc circuit breaker (MCL-HCB) is proposed in this paper. Compared with the typical HCBs, the MCL-HCB can achieve full selective protection of all connected dc lines with significantly reduced investment costs. Besides, it can suppress the rising speed of the fault current by embedded CLIs, while eliminating their negative impacts on the fault current interruption. The feasibility and superiority of the proposed MCL-HCB are verified by simulations in the PSCAD/EMTDC software and experiments in the scaled-down experimental setup. Besides, the performance comparison between the MCL-HCB and existing solutions is elaborated.