Space Charge Accumulation at Material Interfaces in HVDC Cable Insulation Part I—Experimental Study and Charge Injection Hypothesis
Journal article, 2020

On-site installation of accessories on extruded polymeric high voltage cables in a common practice. The procedure requires the shaping of the physical interface between the cable insulation surface and the pre-molded accessory body. On such interfaces, rough surfaces should be avoided in order to limit space charge accumulation in the insulation, which affects the cable performance by reducing insulation life-time, creating conditions for local field enhancement, and, respectively, the formation of possible breakdown path e.g. by electrical treeing. Space charge measurements on cable insulation peelings were undertaken to assess the space charge injection and accumulation on interfaces with varying degrees of surface roughness in order to improve understanding on this subject. The results of the measurements confirm the hypothesis regarding the enhancement of charge injection from rough surfaces when electric field strength exceeds a certain level. The accumulated charge density in the material is shown to strongly depend on the field strength and temperature in both polarization and subsequent depolarization measurements. These results emphasize that a bipolar charge transport model that incorporates field and temperature dependencies of charge injection, trapping, detrapping, and recombination processes needs to be adopted to accurately describe the observed electric conduction phenomena.

field enhancement factor

HVDC extruded cable

physical interfaces

space charge measurement

charge injection

roughness enhanced charge injection

surface roughness

insulation interfaces

pulsed-electro-acoustic method

Author

Espen Doedens

Nexans Norway AS

Chalmers, Electrical Engineering, Electric Power Engineering, Power grids and Components

E. Markus Jarvid

Nexans Norway AS

Raphaël Guffond

Nexans Research Centre (NRC)

Yuriy Serdyuk

Chalmers, Electrical Engineering, Electric Power Engineering, Power grids and Components

Energies

1996-1073 (ISSN)

Vol. 13 2005-2021

Areas of Advance

Energy

Subject Categories

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.3390/en13082005

More information

Latest update

6/5/2020 7