A Multiport DC Circuit Breaker for High-Voltage DC Grids

Abstract

DC circuit breakers (DCBs) are expected to isolate faults in high-voltage DC grids. Multiple DCBs are required for a DC bus connected to multiple lines, and they form a DCB cluster. To reduce the construction cost, the DCB cluster can be integrated into a multiport DCB (MDCB). The integration of proactive-DCBs has been widely researched. However, in previous articles, only a few MDCBs have been proposed to integrate current-injection-DCBs (C-DCBs), and the interruption reliabilities of these MDCBs are reduced because multiple mechanical switches (MSs) should be opened during an interruption. This article proposes a novel MDCB to integrate C-DCBs. In the proposed MDCB, all ports share one main breaker and one energy absorber. The interruption operations during a port fault and bus fault are detailed, and the backup protection for an MS failure is presented. The parameter designs of the proposed MDCB are discussed. The proposed MDCB is compared with the DCB cluster to show the economic advantage and is compared with the previous MDCB to show the reliability advantage. Finally, the proposed MDCB is validated using PSCAD/EMTDC simulations.