• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.7
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• pp.340-345
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• 2001

Because they have superior insulating properties and lower in price than their ceramic equivalents, polymeric insulators have been used in outdoor insulators. But polymeric insulators mainly using in an heavy contamination area of outdoor could be easily attached to contaminants such as salt and by-products of industrial processes. To understand its effect on contaminants adhered to these insulators, we dismounted polymeric insulators adhered contaminant in the field, and evaluated its electrical characteristics, CA, and ESDD. We also manufactured slurry mixed by some kaolin and salt for the artificial contamination test and measured the degree of contaminant, AC leakage current for these contaminated samples. Consequently, the adhered contaminants to its surface is likely to be affected the performance of insulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.145-146
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• 2005

This study performs a simulation for an accumulation mechanism of contaminants, which were produced in an industrial belt of inland, on the surface of insulators. From the simulation, silicon insulators presented higher accumulation than that of EPDM(Ethylene Propylene Diene Terpolymer : EPDM) insulators on the same distance in the case of the Virgin polymer insulator, and this result presented the same result in the insulator applied in actual fields. In the case of the accumulation test for the Virgin insulator and insulators used in actual fields, it is evident that the Virgin insulator presented more accumulation than that of the insulator used in actual fields. The results can be caused by the generation of LMW (Low Molecular Weight) on the external material of polymer insulators, and the level of the accumulation can be changed according to the degree of the continuous generation of LMW.

• 전기의세계
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• v.18 no.2
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• pp.15-20
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• 1969

The main focus of this paper is on the study of the .gamma. ray irradiation effect upon the electrical properties of a B-kind insulator which is one of the inorganic insulators. The mica is so typical of the B kind insulators as to be selected for a sample. DC, AC, and Impulse voltage is applied to the variable .gamma. ray irradiated dose samples with the constant time duration and the time variable samples with the .gamma. ray irradiated dose. The dielectric breakdown voltage and dielectric constant are measured from the samples and we get the experimental data that the dielectric breakown voltage variations are relatively large, but the dielectric constants are almost constant. The above conclusion is useful for the selection and application of the inorganic insulators under the irradiation effects, and we expect that the conclusion can apply to not only B-kind insulators but also the inorganic insulators.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.10-14
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• 2001

In order to assess the long-tenn reliability of polymer insulators for distribution power systems, we have developed the accelerated aging test method which can simulate the operation conditions. In this study, 3000 hours aging test for 4 kinds of polymer insulators has been completed by the developed accelerated aging test. After 3000 hours aging test, visual inspection and electrical tests were carried for identifying a change of characteristics. Some specimens showed the surface erosion and the manufacturing defect. In the electrical tests, the wet flashover voltage was significant1y decreased by the accelerated aging test. In comparison with the field-aged polymer insulators, it can be concluded that the developed test method can evaluate the long-tenn reliability within short time and screen the manufacturing defect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.847-858
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• 2000

The aging characteristics of 2 kinds of 3 years field-aged distribution polymer insulators which were dismounted from 5 regions have been investigated by electrical test and material characterization. Although the tan $\delta$of specimens prepared from weathershed was increased with surface aging, the tan $\delta$and leakage current of real products had no difference between virgin and dismounted ones. Due to the aging, all dismounted polymer insulators had micro-cracks on the surface of weathershed and only the products of manufacturer B showed the reduction of OIT(oxidation induction time). But, there were no differences between virgin and dismounted products in contact angle and chemical structure. Therefore, it can be considered that the aging is only limited on the surface of dismounted polymer insulators and that NMR technique are very useful to evaluate the aging of polymer materials.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1948-1950
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• 2000

Polymeric composite insulators have been in use for outdoor insulation. However, our knowledge about their long-term performance in an outdoor environment is still very limited. Especially, these insulators are subjected to the environmental stress such as ultraviolet radiation, electrical stress, mechanical load, etc.. Hence, in this paper, we simulated the factors having influence on aging of polymer insulators using the combined aging test chamber. In order to evaluate an aging characteristics with time, we measured leakage current on these insulators to make out the degree of aging.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.498-502
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• 2002

Section insulators are indispensible devices for the electric railways, which divide electrical connections between the trolley lines without losing mechanical connections, and this means that they should have both good electrical insulation performance and mechanical performance for pantograph interaction. This paper reviews some technical aspects of the several type section insulators and makes analysis of difficulties during operation. The closed type section insulators are proposed for newly electrified railways, because they have good mechanical and electrical performances for high speed trains up to 200[km/H]. Technical specifications of closed-type section insulators based on survey of the advanced technologies are provided, and also the neutral section configuration method which might be the best solution for newly electrified railways in Korea of 200km/H speed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.392-396
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• 2004

Experimental equipments for long-term outdoor tests of EHV insulators in outdoor were constructed. The testing insulators have been energized with 89 [kV] phase-to-ground AC voltage under identical condition at station, and the investigation was carried out for leakage current and various environments such as temperature, relative humidity and wind velocity. The test results of leakage current wave trends have forms on distorted waves including harmonics. The porcelain and glass insulators have low leakage current in case of daytime because moisture and humidity have relative low values. In comparison with these conditions, high leakage current was shown at dawn and rainy day due to high humidity. However, leakage current of polymer insulators was shown approximately $129[{\mu}m]$ without relation to the weather due to hydrophobicity on their surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05a
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• pp.82-85
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• 2000

Polymeric composite insulators are used for outdoor insulation. However, our knowledge about their long-term performance in an outdoor environment is still very limited. The electrical stress caused the surface of these insulators to become degradation. In order to evaluate the tracking resistance of polymer insulators, we performed the tracking wheel test which is recommended by CEA LWIWG-01. And the flashover voltage tests were conducted for understanding electrical characteristics after tacking wheel test. Also, these insulators are studied by characterization methods such as contact angle measurement, SEM, etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.146-149
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• 2004

In order to analyze the physical and chemical characteristics of the home production porcelain insulators by change of the alumina addition amount, 36000lbs ball socket type suspension insulators which were manufactured in 1989, 1995 and 2001 removed in transmission line and an experiment was performed. By the result, 8 wt.% alumina that influences the mechanical properties and arc resistance properties in case of insulators that were manufactured in 1989 was contained. Amount of alumina was contained most by 17 wt.% in case of insulators that were manufactured in 2001.