Simulation of Reverse Electrical Trees using Cellular Automata

Many models have been formulated for electrical tree propagation along many simulation techniques. In these models, electrical trees commonly grow from the needle electrode towards the plane-grounded electrode. Empirical evidence has shown that under certain conditions, ‘reverse trees’ initiate and grow from the plane electrode towards the needle. This phenomenon has not been simulated yet. This paper explores the hypothesis that reverse trees are caused by irregularities of the planar surface of the sample, and when the forward tree is near to the plane electrode, a sufficiently high electric field can be generated and be able to initiate a reverse tree from the plane. Cellular automata modelling technique was used to simulate twodimensional tree growth. The results show that, under the modelling assumptions and the simplified model created, irregularities (roughness) of the plane surface of the sample are the main cause of reverse trees. The size of the irregularities did not seem to be an important parameter determining the size of the reverse tree. A more detailed model and improved simulation technique is needed to deepen these conclusions.