Experimental study of back commutation in low voltage circuit breaker

Summary form only given. During the interuption of a short circuit current with a circuit breaker, an arc is formed in order to eliminate the energy stored in the electrical network. When the operation is performed by a miniature circuit breaker, the arc moved from an ignition area towards a quenching area. In some cases, a phenomenon of arc re-ignition outside the quenching area and far from it (several centimeters) may occur. The so-called back commutation increases the interruption time and the energy expended in the breaker and as a result restricts its efficiency. Our works deal with the study of the arc restrike mechanism. A model breaker has been designed to generate arc restrikes in the ignition area under well known conditions. Typical breaking time and peak current intensity are respectively 10 ms and 5 kA. The set up enables the diagnostic evaluation of very small current (down to several tens of amps) in the limited critical region where the arc restrikes, owing to a novel high sensitivity current measurement device.