posted on 2012-03-13, 16:07authored byLen A. Dissado, John C. Fothergill, K. S. Bromely
The discharge-avalanche (D-A) model for electrical tree propagation in polymers is founded entirely upon basic physical concepts. Electrical discharges in an existing tree structure are taken to raise the electrical field in the polymer both along the discharge path and particularly at the tree tips. As a result of the field increase, electron multiplication avalanches occur within the polymer causing damage, possibly through ionisation of polymer molecules, which is accumulated over a period of thousands (or more) cycles and eventually leads to a tree extension of limited size. The assumption that the damage produced in an avalanche is proportional to the number of ionisations allows the model to be expressed quantitatively in terms of material properties: such as the ionisation potential, I; the impact-ionisation length parameter λ; the critical number of ionisations for tree extension Nc; discharge features such as the number of 1-electron initiated avalanches per half cycle, Nb ; and the potential difference ΔV between the start and end of the avalanche over a distance Lb.
History
Citation
Electrical Insulation and Dielectric Phenomena, 1998, Annual Report, Conference on, Vol. 2, pp. 649-652.
Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Engineering
Source
67th Annual Conference on Electrical Insulation and Dielectric Phenomena, Atlanta, GA
Version
AM (Accepted Manuscript)
Published in
Electrical Insulation and Dielectric Phenomena
Publisher
Institute of Electrical and Electronics Engineers (IEEE)