Initiation and Growth Characteristics of Electrical Trees at Ultra-Low Frequency Voltage

This paper investigates the effects of ultra-low frequency (ULF) voltage amplitude and frequency on the initiation and growth characteristics of electrical trees in cross-linked polyethylene (XLPE) insulation. The needle electrode was inserted into the XLPE cable insulation to prepare the needle plate electrode sample, which was used to initiate the electrical tree. The microscopic observation system was used to record the growth process of electrical trees. At the same time, the influences of ultra-low frequency voltage and power frequency voltage on the initiation voltage of electric tree were compared and analyzed. The results show that the initiation voltage of electrical trees decreases with the increase of voltage frequency. The growth rate and fractal dimension of the electrical tree increase with higher voltage amplitude or frequency.