The aim of this article is to investigate the extent of space charge accumulation due to a temperature gradient in comparison with other charge-supply mechanisms, particularly injection from the electrodes. For this purpose, space-charge measurements were carried out on HVDC cable models under application of different temperature gradients across the cable insulation, above and close to the threshold field for space-charge accumulation. The main results, consisting of space-charge patterns and extracted quantities, are discussed here.

The electric field distribution of cable insulation systems under HVDC can be affected significantly at interfaces due to space charge build-up. In this article, the second part of a three-article series, face and space charge accumulation are analyzed first in terms of macroscopic physics, then through approximate mathematical models that will be used to fit experimental data obtained for model cables having two insulation layers and constituting cylindrical interfaces.