Development of A Supercritical Fluid-Insulated Fast Mechanical Switch for MVDC Hybrid Circuit Breakers

The Medium Voltage Direct Current (MVdc) circuit breaker is one of the enabling technologies for the increasingly popular MVdc grids. The MVdc hybrid circuit breaker EDISON ("Efficient DC Interrupter with Fault Protection") has been developed, exhibiting superior properties compared to other dc hybrid circuit breakers, including higher efficiency, faster switching speed, and increased power density. The key component of EDISON is its fast mechanical switch (FMS), which features a compact design utilizing a piezoelectric actuator and supercritical CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> as the dielectric medium. This paper focuses on the design of the FMS, presenting results from finite element analysis (FEA) and experimental studies across mechanical, dielectric, thermal, and magnetic domains.