Title :
Water causing a nonlinear dielectric response of water treed XLPE characterized by FTIR microspectrometry
Author :
Hvidsten, S. Verre ; Ildstad, E.
Author_Institution :
Dept. of Power Eng., Norwegian Univ. of Sci. & Technol., Trondheim, Norway
Abstract :
Recently, the nonlinear dielectric response of water treed XLPE cables has been explained by voltage assisted water ingress into water treed regions. The purpose of the work presented here was to characterize the form of water within the water tree structure. This paper presents results from micro-FTIR experiments performed on 100 μm thick water treed XLPE slices microtomed from a 24 kV service aged cable. Water content of up to 2% was found in vented water tree structures. The majority of this was determined to be free liquid water. Some sections of the free branches were, however, found to be hydrophilic, indicating water being bound to the polymer. The water content was highest in the tree branches and lowest at the tip of the trees and in the root region close to the insulation screen. The length of these regions was typically 200-300 μm
Keywords :
Fourier transform spectroscopy; XLPE insulation; ageing; infrared spectroscopy; insulation testing; moisture measurement; power cable insulation; power cable testing; trees (electrical); 100 mum; 200 to 300 mum; 24 kV; FTIR microspectrometry; free liquid water; hydrophilic branches; insulation screen; microtomed slices; nonlinear dielectric response; root region; service aged cable; tree branches; voltage assisted water ingress; water content; water tree structure; water treed XLPE cables; Aging; Cable insulation; Dielectric losses; Dielectrics and electrical insulation; Microscopy; Polymers; Power engineering; Testing; Trees - insulation; Voltage;
Conference_Titel :
Electrical Insulation, 1998. Conference Record of the 1998 IEEE International Symposium on
Conference_Location :
Arlington, VA
Print_ISBN :
0-7803-4927-X
DOI :
10.1109/ELINSL.1998.704658
