Insulation performance of pressurized liquid helium under quench-induced thermal bubble disturbance for superconducting power apparatus

Author

Chigusa, S. ; Maeda, H. ; Taniguchi, Y. ; Hayakawa, N. ; Okubo, H.

Author_Institution

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

Volume

6

Issue

3

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

385

Lastpage

392

Abstract

We have been studying quench-induced `dynamic´ breakdown characteristics of LHe and have already found that the electrical insulation performance of LHe was degraded drastically by the thermal bubble disturbance due to quench of superconductors. In this paper, in order to improve the insulation performance of LHe under quench conditions, we measured dynamic breakdown and prebreakdown characteristics of pressurized LHe. Experimental results revealed that breakdown voltage of LHe under quench conditions at 0.2 MPa was greatly improved, reaching 2 to 4× compared with that at atmospheric pressure under both uniform and non-uniform electric fields. Moreover, for practical and efficient insulation design of superconducting power apparatus, we investigated the dynamic breakdown voltage of LHe as functions of pressure and gap length

Keywords

bubbles; electric breakdown; insulating materials; liquid helium; quenching (thermal); superconducting coils; 0.2 MPa; breakdown characteristics; breakdown voltage; electrical insulation performance; gap length; nonuniform electric fields; prebreakdown characteristics; pressurized liquid helium; quench-induced thermal bubble disturbance; superconducting power apparatus; uniform electric fields; Cryogenics; Dielectric liquids; Dielectrics and electrical insulation; Electric breakdown; Electrodes; Helium; Superconducting coils; Superconducting filaments and wires; Superconducting transmission lines; Thermal quenching;

fLanguage

English

Journal_Title

Dielectrics and Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

1070-9878

Type

jour

DOI

10.1109/94.775627

Filename

775627