Coaxial insulator surface flashover character in different self-magnetic field conditions

The coaxial self-magnetic field generated by pulsed current of low impedance generator could affect the vacuum insulator surface flashover characteristics because of the magnetic-flashover-inhibition (MFI) effect. In coaxial electrode structure, the ratio of electric field E and magnetic field B is independent of variety of radius, but only depends on circuit parameters. Four coaxial structures are designed with different ratios of E/cB, viz. , 0.041, 0.05, 0.056, and 0.062. Two type experiments, with and without magnetic field, are carried out. The experimental results show that, the surface flashover voltage with appropriate magnetic field orientation to MFI is increased obviously, compared to that without magnetic field. The smaller the ratio of E/cB is, the higher the flashover voltage is. When the ratio of E/cB is 0.041, the flashover voltage can increase to about 1.3 times that in non-magnetic field condition. But flashover voltage will decrease when the orientation of magnetic field is reversed.