Different Space Charge Behavior of Materials Used in AC and DC Systems

The aim of the present work is to evaluate the behavior, from the space charge accumulation phenomenon point of view, of three different XLPE specimens used as insulation materials in high voltage systems. Considering that under DC stress the charge accumulation is more relevant as compared to the AC case, in the specimens for DC applications additives are typically added. In this work, three different specimens are analyzed. One is a free additive sample used conventionally under AC stress and two others include different additives that are used under DC stress. In order to measure the space charge accumulation, the Pulsed Electro Acoustic (PEA) method has been employed. For each sample, the three-dimensional space charge patterns and the electric field distributions have been acquired and analyzed. Finally, a comparison among the tested specimens has been made.