Modeling the Effect of Ionic Dissociation on Charge Transport in Transformer Oil

Transformer oil is one of the most important and widely used of all dielectric liquids. Significant research into the insulating properties of transformer oil has been carried out. Much of this work has focused on the development of streamers, and how they can result in the electrical breakdown of the oil. Due to the complex nature of transformer oil no universally accepted model describing streamer initiation and propagation has emerged. In this paper, a model is developed which explores the role played by electric field dependent ionic dissociation in the initiation and propagation of streamers in transformer oil. This model couples the electrodynamics of charge transport to thermal enhancement in transformer oil. Using the COMSOL Multiphysics software application and the finite element method, the model is solved to show that ionic dissociation alone will not lead to a high enough temperature rise to initiate a streamer in transformer oil.