Stochastic Modeling of Electric Tree Progression due to Partial Discharge Activity

In this work, a stochastic model has been developed to simulate the effects, on tree progression, of partial discharge activity within tree tubules and void inclusions in the base matrix. Tree progression is assumed to proceed in a step-wise fashion under the combined influence of actual field conditions and random unknown factors. When the field at a tree tip exceeds the critical field for the given material, the material erodes, forming fine filamentary tree channels. Partial discharges (PD) occur within the tree tubules. During the pd activity, charge is redistributed through the channel, resulting in a space charge distribution along the walls of the tree channel, as well as the tip of the tree tubule. In this work, the effects of various charge distributions on the tree walls after PD activity, on the nature of tree progression were studied. It was found that the magnitude of the charge density strongly influences the nature of tree growth, resulting in tree-like trees to bushy trees. Additionally, polymeric dielectrics include voids in the base matrix during the manufacturing process. Simulations were carried out to investigate how the presence and geometry of voids affect tree progression