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A Multigap Structure for Power Frequency Arc Quenching in 10-kV Systems

In order to improve the ability to quench the power frequency arc following broken down by lightning overvoltage, this paper introduces a multigap structure and analyses the process and mechanism of arc quenching in the arc chamber. A simulation model has been established based on the magnetohydrodynamics theory to analyze the characteristics of the plasma in an arc chamber. A series of comprehensive tests have also been carried out to test the 10-kV arc quenching structure by using a test platform, which can generate power frequency voltage and lightning impulse voltage. Results show that the multigap arc quenching structure can quench an arc quickly after flashover, and the quenching time occurs at zero crossing of the power frequency follow current. After extinction, arc does not occur any more when the power frequency voltage is recovered. The arc voltage drop in the proposed structure guarantees that the power system does not suffer from trip accident which may be caused by short-circuit overcurrent protection.