Model for partial discharges associated with treeing breakdown: II. tree growth affected by PDs

Wu, Kai; Suzuoki, Yasuo; Mizutani, Teruyoshi; Xie, Hui

doi:10.1088/0022-3727/33/10/311

Cited by 24 publications

(16 citation statements)

References 39 publications

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“…The increasing branch density (fractal dimension) was due to the greater number of side branches that could discharge as the applied voltage was increased and the decreasing growth rate due to reduced electrostatic energy dissipation in the outermost tree segments. Other processes, such as gas pressure buildup within the tree channels [11,12] or a competition between different growth mechanisms [33], need not necessarily be invoked to explain the branch to bush transition. This tree growth-voltage behaviour was therefore determined by the process itself and not by the material.…”

Section: Discussionmentioning

confidence: 99%

A deterministic model for the growth of non-conducting electrical tree structures

Dodd

2002

J. Phys. D: Appl. Phys.

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Electrical treeing is of interest to the electrical generation, transmission and distribution industries as it is one of the causes of insulation failure in electrical machines, switchgear and transformer bushings. In this paper a deterministic electrical tree growth model is described. The model is based on electrostatics and local electron avalanches to model partial discharge activity within the growing tree structure. Damage to the resin surrounding the tree structure is dependent on the local electrostatic energy dissipation by partial discharges within the tree structure and weighted by the magnitudes of the local electric fields in the resin surrounding the tree structure. The model is successful in simulating the formation of branched structures without the need of a random variable, a requirement of previous stochastic models. Instability in the spatial development of partial discharges within the tree structure takes the role of the stochastic element as used in previous models to produce branched tree structures. The simulated electrical trees conform to the experimentally observed behaviour; tree length versus time and electrical tree growth rate as a function of applied voltage for non-conducting electrical trees. The phase synchronous partial discharge activity and the spatial distribution of emitted light from the tree structure are also in agreement with experimental data for non-conducting trees as grown in a flexible epoxy resin and in polyethylene. The fact that similar tree growth behaviour is found using pure amorphous (epoxy resin) and semicrystalline (polyethylene) materials demonstrate that neither annealed or quenched noise, representing material inhomogeneity, is required for the formation of irregular branched structures (electrical trees). Instead, as shown in this paper, branched growth can occur due to the instability of individual discharges within the tree structure.

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Section: Discussionmentioning

confidence: 99%

A deterministic model for the growth of non-conducting electrical tree structures

Dodd

2002

J. Phys. D: Appl. Phys.

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“…They can propagate through the dielectric by means of partial discharge (PD) activity occurring within the existing structure [2]. Therefore, PD activity is a valuable indicator for the extent of the electrical tree growth.…”

Section: Introductionmentioning

confidence: 99%

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

Dodd

Chalashkanov

Fothergill

2008

2008 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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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

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“…In our previous papers [1][2][3], partial discharges (PDs) in tree channels and the process of tree growth in the early stage after tree initiation were studied. However, when the electrode separation is long or the applied voltage is low so that the tree cannot directly grow to the plane electrode, the tree almost stops growing when it extends to a certain length; and after a long time, fast re-growth of new channels and a reduction of the PD magnitude are often observed [4,5].…”

Section: Introductionmentioning

confidence: 99%

Model for partial discharges associated with treeing breakdown: III. PD extinction and re-growth of tree

Suzuoki

Mizutani

et al. 2000

J. Phys. D: Appl. Phys.

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When the electrode separation is long or the applied voltage is low, the tree cannot directly grow to the plane electrode, and extinction of partial discharge (PD) with the re-growth of new channels can be observed after a long time. Before PD extinction, the light emission of the PD changes from the whole tree structure to only the region near the needle tip, and the PD pattern also changes from wing-like to turtle-like. These phenomena are considered to be related to the increase of channel conductivity by PDs. Assuming the channel conductivity is higher in the region at tree tips or in the tree channels than near the needle tip, the simulation results coincide with the experimental results.

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Model for partial discharges associated with treeing breakdown: II. tree growth affected by PDs

Cited by 24 publications

References 39 publications

A deterministic model for the growth of non-conducting electrical tree structures

A deterministic model for the growth of non-conducting electrical tree structures

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

Model for partial discharges associated with treeing breakdown: III. PD extinction and re-growth of tree

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