Keywords: circuit breakers, micro-electromechanical switches, current interruption, switching string, zero current switching, power distribution, critical infrastructures, electricity infrastructures, EPNES, efficiency, security
Power circuit breaker using micro-mechanical switches
The objective of this research is to investigate innovative power distribution components based on micro-electromechanical systems technologies integrated with advanced optimisation methods to improve the performance of electric power distribution systems. A novel medium voltage circuit breaker using two switching string assemblies has been developed. The building block is a switching unit, which includes micro-switch shunted by a diode and a resistance. 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. The circuit breaker contains two switching string assemblies connected in series. One of them interrupts the current in the positive the other in the negative cycle. The opening of the mechanical switches transfers the current to the diodes, without any arcing. The diodes interrupt the current at zero crossing. The project objective includes an educational component: to bring innovative topics in power distribution engineering to practising engineers (e.g., continuing education) as well as engineering students. The design appears to be a logical step in innovative power circuit breaker design that allows better control of circuit interruption than conventional breakers.