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Surface Flashover Characteristics of PPLP According to Its Orientation in Cryogenic Environment.

Authors :
Jin-Yong Na
Ik-Soo Kwon
Jae-Hong Koo
Mansoor Asif
Bang-Wook Lee
Source :
IEEE Transactions on Applied Superconductivity; Jun2018, Vol. 28 Issue 4, p1-5, 5p
Publication Year :
2018

Abstract

Polypropylene laminated paper (PPLP), which is used as the main insulation material of the stop joint box (SJB), has excellent dielectric characteristics in cryogenic environment. Despite excellent dielectric characteristics of PPLP, the interface between liquid nitrogen (LN<subscript>2</subscript> ) and PPLP of the SJB is very vulnerable to the surface flashover. Therefore, it is necessary to investigate the surface flashover characteristics of dielectric materials including LN<subscript>2</subscript> and PPLP for the insulation design of the SJB. PPLP has two orientations according to the direction of fiber in Kraft paper that are cross direction (CD) andmachine direction (MD). The research on themechanical properties of PPLP has been reported since there are differences in physical properties depending on its orientation. However, the study of the surface flashover characteristics of PPLP in the cryogenic environment according to its orientation has not been reported yet. Thus, the surface flashover characteristics of PPLP according to its orientations should be examined to ensure the reliability of the SJB connecting the high-temperature superconducting (HTS) dc cable. In this paper, the surface flashover characteristics of the PPLP in cryogenic environment in accordance with its orientation was fully investigated. The dc surface flashover tests were performed with different orientations of PPLP and various gap distances. In addition, the surface leakage currents were measured by increasing voltage at fixed gap distance. From the test results, the dc surface flashover voltage of CD was found to be 15-20% higher than that of MD. In addition, the breaking point of CD was three times higher than MD, and beyond the breaking point, the surface leakage current of CD was lower than that of MD. Consequently, the surface flashover characteristics of PPLP are significantly affected by fiber orientations of PPLP. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10518223
Volume :
28
Issue :
4
Database :
Complementary Index
Journal :
IEEE Transactions on Applied Superconductivity
Publication Type :
Academic Journal
Accession number :
128707703
Full Text :
https://doi.org/10.1109/TASC.2018.2800033