Contents I. Introduction
During the interruption of short-circuit currents by low-voltage circuit breakers, the movement characteristics of the arc significantly impact the arc voltage and the overall interruption performance of the circuit breaker. During the disconnection process, the arc gradually elongates under the action of the moving contact, enters the arc extinguishing grid under the contraction force of the magnetic field lines, and is cut into several short arcs by the grid. During the cutting process, the arc plasma strongly interacts with the metal grid, forming a cathode anode arc root on the surface of the grid, resulting in a near pole voltage drop. Under the effect of near pole voltage drop, the arc voltage will significantly increase. Under the action of de ionization and cooling of the arc extinguishing grid, the arc is extinguished when the current crosses zero. However, when the arc extinguishing performance of the circuit breaker is weak, the phenomenon of arc reignition may occur, resulting in the failure of the circuit breaker to open. Research has shown that there is a certain relationship between the voltage before the arc extinguishes and whether the arc reignites [2]–[4]. Through statistical analysis of successful and failed disconnection cases, it was found that there was no significant difference in arc energy between successful and failed disconnection cases, and the only relevant measurement parameter was the “outlet voltage”, which is the voltage within about 20 microseconds before the arc current crosses zero [5]–[6]. Therefore, it is very important to analyze the waveform and dynamic of the arc voltage during the short period before zero crossing in the low voltage circuit breaker extinguishing chamber.
