Statistical Analysis of Partial Discharges from Electrical Trees Grown in a Flexible Epoxy Resin

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-Electrical treeing is a long-term degradation mechanism in polymeric insulation, which can lead to electrical failure of HV insulation systems. The rate at which trees grow across the insulation depends on the PD activity occurring within them and hence the detection of the onset of electrical treeing could be established by PD monitoring. In this paper, a statistical analysis of the partial discharges detected during the growth of trees in an epoxy resin will be reported. The aim of this work was to provide additional insight into the physical mechanisms that lead to the observed fluctuations in the partial discharge activity. The results demonstrate interesting correlations between a number of statistical parameters, such as average discharge magnitude and standard deviation in the partial discharge amplitudes. These correlations could also be related to physical parameters such as the applied voltage magnitude and the measured power dissipation due to the partial discharges occurring during tree growth. The implications of this work for deterministic methodologies for the simulation of tree growth as well as for condition monitoring using feature recognition strategies for the early detection of tree growth will be discussed. Permanent repository link

The role of bulk charge transport processes in electrical tree formation and breakdown mechanisms in epoxy resins

“…In the cases where thermal breakdown had occurred, no PD data were collected. At low temperature and low moisture the average values of both discharge rates and magnitudes are typical of those characterizing the PD activity during the electrical tree growth [33,34]. However, at high values of temperature and/or humidity the average PD magnitudes decrease, while the corresponding number of PDs per second increases significantly.…”

“…The value of value of GV was set to zero to model electrical tree channels that are non-conducting and the value of CB was chosen to be 2.2nF. In both cases the peak value of the sinusoidal applied stress was 19.6 kV/mm, and the values for Eon and Eoff were 11.6 kV/mm and 10.9 kV/mm for the positive polarity and 11.3 kV/mm and 10.7 kV/mm for the negative polarity respectively, since the treeing process is essentially symmetric with respect to the voltage polarity [33]. A study of the PD inception and extinction voltages and stresses in voids in different insulating materials can be found in [36].…”

The coming of Age of HVDC extruded power cables

“…A detailed theory of electrical tree formation was published with Len Dissado [19]. This work has also continued more recently [20][21][22][23].…”

Statistical Analysis of Partial Discharge during Electrical Tree in Silicone Rubber Nanocomposites under Elevated Temperature

“…The difference is that different materials are used; while Dodd et al [12] and Gulski [13] studied PD activities during electrical tree growth in flexible epoxy resin and PE, respectively, but this study is on the PD activities during tree growth in neat silicone rubber and silicone rubber-based nanocomposites. Thus, different materials would be expected to result in different PD characteristics with PD resistance capability that is expected in silicone rubber-based nanocomposites material.…”

“…In general, motivating factor that necessitated the use of conventional statistical tools for the PD analysis was based on the study done by Dodd et al [12] and Gulski [13]. The difference is that different materials are used; while Dodd et al [12] and Gulski [13] studied PD activities during electrical tree growth in flexible epoxy resin and PE, respectively, but this study is on the PD activities during tree growth in neat silicone rubber and silicone rubber-based nanocomposites.…”