Abstract
We have investigated the partial discharge (PD) due to electrical treeing degradation in polyethylene. It was found that the magnitude of PD due to an electrical tree is proportional to the instantaneous voltage, while the PD occurrence is governed by the time derivative of the applied voltage (dv/dt). Based on the results, a model for electrical treeing discharge was proposed. By utilizing the model, the Monte Carlo computer-simulation was carried out for sinusoidal and triangular applied voltages. The simulated PD patterns were similar to the experimental results, suggesting the validity of the proposed model. The simulation revealed that the tree discharge path length and its distribution determined the PD pattern. The so called wing-like pattern from a treelike tree was obtained for long discharge path and broad distribution, while the PD pattern from a bush-like tree was obtained for long discharge path and narrow distribution. This indicates the potential of PD pattern recognition for diagnosis of treeing degradation.
