Experimental and numerical studies of arc restrikes in low-voltagecircuit breakers

This paper is devoted to the study of the arc restrike phenomenon in low-voltage circuit breakers. We focused our interest on the type of arc restrike that can be described as a sudden reignition in the arcing contact region while the arc was situated in the quenching chamber a few tens of microseconds before it occurs. Our experimental investigations have established that the critical arcing contact region is still crossed by a so called residual current on the order of several amperes. A gas temperature around 4200 K was derived from electrical measurements in this region before the arc restrike occurrence, We also demonstrate that the restrike takes place through the growth of the remaining current of several amperes in the arcing contact region. A numerical approach was carried out with a two-dimensional hydrodynamic code in order to simulate the gas behavior in the arcing contact region before and during the arc restrike phenomenon. The same temperature as the measured one is calculated just before the restrike. It is demonstrated that the current density appears to be the most sensible quantity. A critical value of 5 A/cm² was calculated