Modeling and simulation of water treeing in dielectric samples

A study and analysis of water tree phenomena in insulating materials was carried out on samples of XLPE. A model was prepared and simulation program was developed using the finite element technique to investigate the effect of different parameters. Alternating voltage was applied at room temperature, different needle tip angles were tried at different voltage levels. The relative permititivity of water was changed from 6 to 80. Water trees are initiated from the micro-voids in the dielectric material at the needle tip. The study included the samples with void and others without void. The results obtained from models are in good agreement with experimental findings. The conditions of inhibition of water trees were investigated, with a main goal of increasing the lifetime of dielectrics and electric equipment.