Direct current (dc) power system protection presents a major challenge due to its unique characteristics, namely the absence of natural zero current crossing points. Thanks to their features, dc protection devices allow the safe commutation of the fault current. Selective protection and fast fault isolation are key features that any dc circuit breaker should feature, assuring minimal power outages and the effective protection of sensitive electronic components. To overcome the liabilities of mechanical circuit breakers (MCBs) and solid-state circuit breakers (SSCBs), several novel concepts of hybrid circuit breakers (HCBs) have been proposed over the years, to take advantage of the benefits of both the MCBs and SSCBs. This article presents an up-to-date state-of-the-art on the technologies applied to dc HCBs and describes novel HCB concepts. Design considerations, challenges, and future trends are also discussed.

中文翻译：

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直流应用混合断路器综述

直流 (dc) 电力系统保护因其独特的特性（即不存在自然零电流交叉点）而提出了重大挑战。由于其特性，直流保护装置可以安全地换向故障电流。选择性保护和快速故障隔离是任何直流断路器都应具备的关键功能，可确保最小的断电并有效保护敏感电子元件。为了克服机械断路器 (MCB) 和固态断路器 (SSCB) 的缺点，多年来提出了混合断路器 (HCB) 的几种新颖概念，以充分利用 MCB 和 SSCB 的优点。本文介绍了应用于直流 HCB 的最新技术并描述了新颖的 HCB 概念。还讨论了设计考虑因素、挑战和未来趋势。