Thomson-Coil Actuator System for Enhanced Active Resonant DC Circuit Breakers

Abstract

Enhanced active resonant (EAR) DC circuit breakers (DCCBs) are a promising set of recently proposed DCCB concepts. As other DCCBs, EAR DCCBs still require a fast mechanical switch. The requirements on the actuator of the mechanical switch depend on the DCCB concept and the DC grid and are derived here for an EAR DCCB. Thomson-coil actuators can open and close mechanical switches sufficiently fast to satisfy the requirements. This work studies experimentally a Thomson-coil actuator system with active damping for an off-the-shelf industrial vacuum interrupter used as mechanical switch in an EAR DCCB. The prototype is explained in detail and extensive measurement results are presented showing that active damping must be perfectly timed to be effective. A novel Thomson-coil driver is proposed and studied experimentally, which operates the Thomson-coil actuator more efficiently by recycling energy during the actuation. Moreover, the novel Thomson-coil driver reduces the capacitive storage by 50 % and allows for faster recharging with lower charging current. Finally, the auto-reclosing and proactive commutation operation of the Thomson-coil actuator system and the interruption capability of the prototype EAR DCCB are demonstrated experimentally.

Experimental Study of Enhanced Active Resonant DC Circuit Breakers

“…5b, respectively. A triggered vacuum gap (TVG) is used as DCS and a vacuum interrupter (VI) with a Thomson-coil actuator described in [29] is used as S in the prototype EAR DCCB. The injection circuit shown in Fig.…”

“…However, the preliminary test results only demonstrated the basic operating principle of EAR DCCBs. [29] focused exclusively on the actuator of the mechanical switch used in EAR DCCBs. The main contribution of this article is an in-depth experimental study of the EAR DCCBs in various operating modes and of a novel commutation process.…”