Resonant Hybrid MVDC Circuit Breakers with In-Line Inductor

Abstract

A major challenge facing wider adoption of medium voltage DC (MVDC) systems is reliability. Applications such as subsea oil and gas extraction, offshore wind energy conversion, etc. are very mission critical, and a single fault can lead to heavy losses to revenue, environment or even life. This paper presents two resonant hybrid circuit breaker (CB) technologies, one with a coupled inductor and another with a single inductor in line with the mechanical relay, primarily targeted for MVDC applications. Since the main path of both the concepts contains only the mechanical relay and the resonant inductor, the steady state efficiencies are very high (can be well over 99.9 %) in MVDC applications. By carefully choosing the inductor and capacitor values, it is also possible to achieve a response time of well within 100 µs. This paper details the design, verification and comparison of the two concepts through simulation.