Electric field profile measurement and modeling in multi-dielectrics for HVDC application

One of the major issues to be considered for the development of polymeric-type DC cable systems is the accumulation of space charges and the consequent distortion of the electric field. These phenomena occur both in the cable and in the accessories, especially at interfaces between different materials. In this respect, accessories, like joints and terminations are key points for the reliability of DC links. They are made with polymeric materials of different nature, the respective dielectric properties having a significant impact on the field distribution and interfacial charge accumulation processes. Therefore, the design of such accessories requires accurate forecasting of the actual field distribution within the insulation, under the non-homogeneous temperature conditions of the cable in service. The aim of the present contribution is to investigate the influence of conductivity on the electric field distribution in multi-dielectrics by experimental measurements and simulation.