Real-time observation of surface charging on a cylindrical insulator in vacuum

Author

Yamamoto, O. ; Takuma, T. ; Tanabe, Y.

Author_Institution

Dept. of Electr. Eng., Kyoto Univ., Japan

Volume

5

Issue

6

fYear

1998

fDate

12/1/1998 12:00:00 AM

Firstpage

961

Lastpage

965

Abstract

By using an electrostatic probe located close to the triple junction on the cathode surface, we have conducted real-time observations of the change in electric field due to surface charging of an insulator in vacuum. A cylindrical sample made of polymethylmethacrylate (PMMA) or Al₂O₃ has been exposed to HVDC. An axisymmetric simulation based on the secondary electron emission electron avalanche (SEEA) theory has been performed. The measured results agreed with the simulation concerning the polarity of the accumulated charge as well as the field strength. The simulation also predicts the inception of charging at a voltage well below the measured flashover voltage. These results clearly support the SEEA theory as a macroscopic mechanism of surface charging of an insulator in vacuum

Keywords

cathodes; electric strength; flashover; insulation testing; organic insulating materials; probes; secondary electron emission; surface charging; HVDC; axisymmetric simulation; cathode surface; cylindrical insulator; electrostatic probe; field strength; flashover voltage; macroscopic mechanism; polymethylmethacrylate; secondary electron emission avalanche; surface charging; Cathodes; Charge measurement; Current measurement; Dielectrics and electrical insulation; Electron emission; Electrostatics; HVDC transmission; Probes; Surface charging; Voltage;

fLanguage

English

Journal_Title

Dielectrics and Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

1070-9878

Type

jour

DOI

10.1109/94.740783

Filename

740783