1996 Fiscal Year Final Research Report Summary
Basic study for improving insulation performance of power cables by observing space-charge dynamics
| Project/Area Number |
07650370
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | Nagoya University |
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Principal Investigator |
SUZUOKI Yasuo Nagoya University, Center for Integrated Research in Science and Engineering, Professor, 理工科学総合研究センター, 教授 (10115587)
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| Project Period (FY) |
1995 – 1996
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| Keywords | POWER CABLE / SPACE CHARGE / PACKET / ANTIOXIDANT / INSULATION DEGRADATION / DIELECTRIC BREAKDOWN / DEGRADATION |
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| Research Abstract |
The objectives of this study are to observe space-charge dynamics in polyethylene for power cable insulation, to discuss their effects on breakdown and degradation phenomena and to find out the guiding principles for preventing breakdown and suppressing degradation. We carried out time-resolved space-charge observation on polyethylene for power cables under high electric fields.
As a result we succeeded in observing periodic formation and transport of a packet-like lumped space charge under very high field near breakdown. The detailed investigation revealed the following. (1) The charge packet tends to be formed when antioxidant is added and/or deteriorated. (2) This phenomena is accompanied by current oscillation. (3) The packet is formed in the bulk, and the internal field in the region of packet formation is periodically enhanced by space-charge accumulation. (4) Antioxidant deteriorated by oxidation is shown to be a possible origin of the carrier generation under periodic enhancement of the local field. Based on the above results, we proposed several models and carried out computer simulation. The above characteristics are successfully reconstructed by some models in which the packet is not due to mobile carriers but due to the deficiency in mobile carriers and carriers generation has very strong field dependence accompanied by slow recombination process.
Even though effects of this phenomenon on breakdown process are not clear yet at this stage, appearance of peculiar carrier generation under high field near breakdown was suggested. It is likely that this type of carrier generation is associated with antioxidant and degradation which leads to breakdown, and, therefore, it is important to continue studying this dynamic space-charge behavior.
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