Study of the Influence of Surface Resistivity while Measuring Space Charge in HVDC Cable with LIPP Method

Because of the limitation of technical level and experimental conditions, the measurement of the space charge distributions in the full-size HVDC cables is still a challenge. In this paper, the influence of the surface resistivity of the shielding layer while measuring space charge with LIPP method was studied. To find out the influence, three kinds of samples were used for measuring the space charge signal under the electric field of 6kV/mm. The shielding layer between the grounding electrode and the detecting electrode of each sample was thinned to increase the surface resistance. The experiment results shows that the after thinning the external shield layer, the space charge signal of the cable has been successful measured.

I. Introduction

In recent years, many efforts have been made in study on space charge distributions of polymer dielectrics [1] . However, because of limitation of measuring technique and the experimental conditions, most of studies are still limited in the interpretation of planar samples and film. For the real long HVDC cable, it is still a difficult problem to measure the space charge distribution.