| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
1. It becomes apparent that the dispersion of tip radius of treeing needle, which has been supplied to all users in the world only by 'O' company in Japan, is far over the tolerance limit speciffied. The problem was reported at CIGRE SC-15 international meeting held in Vienna and informed to 'O' company at the same time. Soon after that it was confirmed that some appropriate counterplans were executed by 'O' company.
2. 'Improved Mason(I.M.) electrode', which is formed by a pit filled with conducting paint, is developed and used in this study instead of the usual electrode system with steel needle inserted into specimen. Endurance tests to electrical treeing in polyethylene and polymethylpentene(TPX) were achieved using I.M. electrode system. As the results, it is confirmed that the yield rate of specimens on which I.M. electrodes are formed was far higher than that of usual specimens with steel needle electrodes. On the other hand, dispersion of T.I.V. data, obtained by specimens with
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I.M. electrode, is so small compared with those with steel needle electrodes.
3. The method to fit 6 optical fibre probes to one specimen, on which an I.M. electrode is formed, is established. A photometry system using photomultiplier is also constructed.
4. Output light signals from one end of optical fibre probes, bundled alltogether, were survayed by the above-mentioned photometory system. Light pulses were observed just before attaining the voltage peaks in every positive and negative half cycles. It was presumed, however, that this light signals were originatd not by electroluminescence, but by small internal discharges, since discharges of a few pC were monitored by the detector at the same time.
5. From the above-mentioned results, It is confirmed that optical fibre probes are usefull for the measurements of electrical insulating materials. It will be requisite, however, to improve sensitivity and S/N of whole measurment systems in order to catch far weak electroluminescence light signals. Less
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