Ultra high molecular weight polyethylene (UHMWPE): Dielectric strength and space charge characteristics

In order to replace old insulation systems based on oil-paper, other materials, such as low density polyethylene (LDPE), high density polyethylene (HDPE) and specially, cross-linked polyethylene (XLPE), have been used. Characterization of new polymeric materials potentially useful for HVDC power cables is an interesting research topic to work on. In this paper, one material whose previous applications have been far away from power engineering, has been studied: Ultra high molecular weight polyethylene (UHMWPE). Firstly, UHMWPE has been characterized in terms of statistical dielectric strength. Moreover, space charge generation and transport has been analysed in an accelerated electrical ageing experiment in order to compare UHMWPE to other polymeric materials such as XLPE or LDPE. In order to measure space charge profiles, the pulsed electro-acoustic (PEA) technique has been applied to polymer sheets withstanding more than 80kV/mm DC for more than 10 days.