Research on Asynchronous Characteristics of Three-Phase Arc in Contactor

Three-phase contactor is an important switching device in a power distribution system. In contactors, unavoidable tolerances create differences in three-phase contact overtravel. The separation of the contacts at different times produces three-phase asynchronous arcs. On the basis of the magnetohydrodynamic (MHD) simulation model, the arc behavior of the synchronous arc and the asynchronous arc are analyzed. An experimental platform based on phase control technology is built. The volt-ampere characteristics and high-speed photography of synchronous and asynchronous arcs are acquired. The influence of phase and actuator speed on the asynchronous arc is analyzed. The experimental and simulation results show that the asynchronous arc makes the three-phase arc more uneven. The higher the lagging phase voltage, the more obvious the unevenness. Increasing the actuator speed can effectively reduce the adverse effects of asynchronous arc.

Automated summary

Three-phase contactor is a vital switching device in power distribution systems, but it is prone to differences in contact overtravel due to unavoidable tolerances, resulting in asynchronous arcs. This study analyzed the behavior of synchronous and asynchronous arcs using a magnetohydrodynamic simulation model and constructed an experimental platform to investigate their volt-ampere characteristics and high-speed photography. The results revealed that the asynchronous arc caused more unevenness in the three-phase arc, with higher lagging phase voltage exacerbating the unevenness. Increasing the actuator speed effectively mitigated the adverse effects of the asynchronous arc.