Initiation of vented water trees from the conductor screen of MV XLPE insulated cables

It has previously been shown for service aged XLPE cables that porous structures in the conductor screen do develop and serve as paths for contaminants and corrosion products from the aluminum conductor initiating vented water trees. It was found that a prerequisite for the formation of such structures is the presence of liquid water at the interface between the conductor and conductor screen causing corrosion. The main objective with this work is to reproduce this phenomenon in the laboratory and to examine if porous zones can develop even without service stress (voltage/current).