Simultaneous imaging of electrical tree growth and partial discharge measurement have allowed 5 stages of tree growth to be identified. Partial discharge (PD) characteristics have been collected from tree growth in needle-plane epoxy resin samples under 15 kV peak AC voltage, and have been shown to behave differently at different stages of tree growth. Initial slow growth is accompanied by large discharges (about 10 pC). Thereafter, growth of fine channels is associated with smaller PDs (about 0.3 pC). It was observed that the tree propagation is further driven by even smaller PDs below the equipment sensitivity. However, when the tree approaches the counter electrode, the PD magnitude increases again and a more substantial tree grows with a low propagation rate. Reverse tree channels then occur from the planar electrode towards the needle, together with higher magnitude PDs characterized by thick and dark branches before breakdown.
|Title of host publication||IEEE Int. Conf. on Dielectrics|
|Publication status||Published - 2016|
|Event||International Conference on Dielectrics 2016 - Montpellier, France|
Duration: 3 Jul 2016 → 7 Jul 2016
|Conference||International Conference on Dielectrics 2016|
|Abbreviated title||ICD 2016|
|Period||3/07/16 → 7/07/16|