Journal ArticleDOI
On the Mechanism of Tree Initiation
Y. Saito,M. Fukuzawa,H. Nakamura +2 more
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TLDR
In this article, a tree formed by grounding will be called "a grounding tree", since the formation of a tree under ac voltages is considered to be due to the repetition of charging and discharing, some relationship may exist between the ac tree and the grounding tree.Abstract:
Although the dc-tree-initiation voltage at a needle electrode in a plastic is very high, a tree can be formed by grounding the needle after charging it with a much lower dc voltage than the tree-initiation voltage. The tree formed by grounding will be called "a grounding tree". Since the formation of a tree under ac voltages is considered to be due to the repetition of charging and discharing, some relationship may exist between the ac tree and the grounding tree. The tree-initiation observed with a voltage composed of dc and ac shows that it is caused by a nearly constant value of the ac component, irrespective of the magnitude of the dc component. This also indicates that the mechanism of the intiation of an ac tree and that of a grounding tree are similar. An explanation is also given as to why the tree shape is branch-like or bush-like with ac voltages.read more
Citations
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Proceedings ArticleDOI
Electrical properties of polymers
TL;DR: In this paper, the application of the dielectric method, especially the depolarization technique, for studying molecular mobilities, i.e., multiple phase transitions in polymeric systems, is discussed.
Journal ArticleDOI
An Investigation into the Growth of Electrical Trees in XLPE Cable Insulation
TL;DR: In this paper, the effects of frequency, voltage, temperature and mechanical stress on the times to breakdown of XLPE cable insulation subjected to highly divergent fields were investigated and it was shown that space charges are dominant in determining the shape of the tree and the time to breakdown.
Journal ArticleDOI
Partial discharges due to electrical treeing in polymers : phase-resolved and time-sequence observation and analysis
TL;DR: In this paper, the authors investigated the PD due to electrical treeing degradation in low-density polyethylene (LDPE), EVA and EAA by a computer-aided partial discharge measurement system which allowed them to obtain phase-resolved PD pulse data.
Journal ArticleDOI
Mechanisms of electroluminescence during aging of polyethylene
TL;DR: In this paper, the authors investigated the role of dissolved gases in polyethylene electroluminescence effects and showed that the light emission is due to radiative recombinations of carriers injected through the metal dielectric interface following the Fowler-Nordheim effect.
Journal ArticleDOI
Growth and partial discharge characteristics of electrical tree in XLPE under AC-DC composite voltage
TL;DR: In this paper, the authors investigated the influence of AC component in HVDC cable system on electrical tree growth and discharge characteristics, and the results showed that the AC component greatly accelerated the developing process of the electrical trees.
References
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Journal ArticleDOI
DC Treeing Breakdown Associated with Space Charge Formation in Polyethylene
TL;DR: In this article, the authors investigated the characteristics of four kinds of trees, dc tree, short-circuit tree, polarity reversal tree and impulse tree, as a function of the voltage-rising speed, period of dc prestress, time before the shortcircuit or the application of a voltage of reversed polarity, impulse voltage, needle electrode material and temperature.
Journal ArticleDOI
Treeing in Polyethylene as a Prelude to Breakdown
Donald W. Kitchin,O. S. Pratt +1 more
TL;DR: In this paper, a method of observing the progressive stages of treeing and final punchout under the microscope is described, and the similarity between the appearance in the final stage of needle breakdowns after preliminary treeing, and that of the breakdown paths from ordinary tests with alternating, direct, or impulse voltage supports the view that in most breakdowns the eventual failure is preceded by treeing.
Proceedings ArticleDOI
Treeing in polyethylene as a prelude to breakdown
Donald W. Kitchin,O. S. Pratt +1 more
TL;DR: In this paper, the authors deal with latent damage that consists of trees formed by partial breakdown of defective or locally overstressed regions in polyethylene insulation, and show trees in various stages in contaminated PE after 21 months at 68 volts per mil AC.