Electrical tree in the crosslinked polyethylene with bowtie trees and the partial discharge occurrence phase angle distribution

We investigated the inception and growth of electrical tree in XLPE with bowtie-tree. A needle-plain electrode was used in the experiment and the influence of position and length of bowtie tree on electrical-tree inception voltage and propagation process was studied. As the bowtie tree was located closer to the needle electrode, the electrical tree inception voltage showed a tendency to decrease and the electrical tree tended to pass through the bowtie tree. At the early stage of electrical tree growth, only the positive partial discharges were observed in the case the bowtie tree was close to the needle electrode, while both positive and negative partial discharges were observed in the case the bowtie tree was away from the electrode. Behaviours of bow-tie trees under semi-uniform applied field are now under investigation.