376 / 2017-04-17 09:41:29

Dependence of Field Enhancement Factor on Power Frequency Voltage in Vacuum

13493,13492

The objective of this paper is to propose a physical change of field emitters on the electrode surface. A rod-plane vacuum gap was designed in a vacuum interrupter. A current and voltage conditioning process was carried out in order to make the rod electrode conditioning saturation. Shots of ac power frequency voltage were applied at different vacuum gaps till breakdown happened and the vacuum gaps were 1.0mm and 0.5mm, respectively. The field emission current and breakdown voltage were measured at the same time. Through Fowler-Nordheim theory analysis, the parameters electric field enhancement factor, field emission area and field emission current density are obtained to represent the physical change of the emitters. The results show that the electric field enhancement factor β and field emission current density jFE decrease with the increasing applied voltage and at a voltage Vc close to breakdown voltage, the trend reverses, i.e. the electric field enhancement factor β and field emission current density jFE increase when the voltage rises from Vc to breadkwon voltage.