Arc Restrike in DC Contactor During Arc Splitting Process Under Inhomogeneous Magnetic Field and Its Evaluation Methodology

Le résumé fourni par la source

The arc extinguishing performance of existing dc contactors has been challenging to meet the development needs of battery electrical vehicles (BEVs), which is mainly manifested in the frequent arc re-strike when the large-capacity dc contactor is breaking. In this research, the arc re-strike under an inhomogeneous magnetic field was investigated by the numerical model in which the precision was proved by experiment, and the severity of arc re-strike under different copper (Cu) vapor concentrations was evaluated. The thermal re-strike and electrical re-strike can simultaneously simulate in this research, and arc re-strike between the contacts and arc re-strike between the splitter plates was discovered. The results show that increasing the magnetic field is conducive to arc extinction, but increasing the magnetic field above 60 mT has little effect on arc duration. The arc re-strike is become severe when Cu vapor concentration is above 60 %, which is related to the small specific heat at constant pressureCpand thermal conductivity λ of the mixed gas at high Cu vapor concentration. The magnetic field saturation threshold and arc re-strike evaluation methodology presented in this paper can be used to optimize the configuration of permanent magnets and the geometric dimensions of arc chamber under the premise of meeting the constraints of breaking capacity and arc re-strike risk.

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