The utilization of micromechanical devices in a power circuit breaker

This article relates to the investigation of innovative power distribution components based on microelectromechanical technologies integrated with advanced optimization methods to improve the performance of electric power distribution systems. A novel medium voltage class circuit breaker using two switching string assemblies has been designed and implemented in a laboratory prototype. The building block is a switching unit, which includes microelectromechanical switch shunted by a diode. Several switching units are connected in series to form the switching string, and several strings are connected in parallel to form the switching string assembly. A magnetic coil activates the switches. A circuit breaker is comprised of two switching string assemblies connected in series. One string interrupts the current in the positive half cycle, and the other interrupts current in the negative half cycle. The opening of the mechanical switches transfers the current to the diodes, without arcing. In this way, the circuit breaker is a hybrid between a solid-state circuit breaker and a true microelectromechanical switch circuit breaker. The study shows the feasibility of building a full-scale unit.