• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.390-395
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• 2004

In order to analyze the physical and chemical characteristics of home production porcelain insulators by change of the alumina addition amount, 360001bs 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, and the relative density and the fracture toughness of insulators appeared by 94.2％ and 1.4 ㎫$.$ $M^{\frac{1}{2}}$, respectively. However, 12 wt.％ alumina was contained in case of insulators that were manufactured in 1995, and the relative density and the fracture toughness of insulators appeared preferably lower by 92％ and 1.3㎫$.$ $M^{\frac{1}{2}}$, respectively. Amount of alumina was contained most by 17 wt.％ in case of insulators that were manufactured in 2001. It was confirmed that the electrical and mechanical characteristics such as the relative density and the fracture toughness appeared excellently by 96％ and 1.7㎫$.$ $m^{\frac{1}{2}}$, respectively.

• International Journal of Safety
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• v.7 no.1
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• pp.21-25
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• 2008

The occurrence of a corona is that electrical discharge due to the heterogeneity that occurs when an electrical field is concentrated in an electrode due to a cusp formed on said electrode. Wire treatment at the end of a 154kV dead end clamp for end users accelerates the occurrence of corona, which in turn leads to power loss and noise. In this study, the characteristics of the corona which occurs between porcelain insulators and support clamps of overhead lines used in l54kV power receiving facilities for end users were investigated. The corona, which cannot be identified by one common method, was measured utilizing a UV image camera. A risk assessment for fire damage and its status was suggested. The stress distribution of the electrical field by length of bare wire was suggested by means of the finite element method (FEMLAB). As a result, it was found to affect a porcelain insulators. These results can be utilized for the enhancement of clamp installation and safety in power facilities.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.199-202
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• 1999

The paper deals with the surface discharge characteristics for porcelain suspension insulators. The micro-crystals were crystallized on the surface of glace coated on the porcelain These micro-crystals may affect the electrical Properties such as flashover voltage. However. not much research have been conducted. In this study. we correlated the surface discharge characteristics to the microstructures. It was confirmed that the micro-crystals on the glaze initiated the flashover when the surface was wetted and/or contaminated.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.342-347
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• 2003

The suspension insulators are subjected to harsh environment in service for a long time. Long term reliability of the insulators is required for both mechanical and electrical performances. We studied an analysing method to find out a deformation of brittle porcelain with a thermal expansion of simulation analysis and experimental results show that cement volume growths affect severely to b mechanical failure ageing.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.327_328
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• 2009

The insulator being used for transmission line is to mount the charged conductor on the tower or other supports. The insulators are classified according to its material: porcelain, glass and polymer. Polymer insulators are also called as composite insulator or non ceramic insulator (NCI). Insulators are a major element of a power transmission system. Since a faulty insulator can lead to a wide spreading blackout, it must have sufficient mechanical and electrical strength. It must be durable, have high electrical insulation and be able to withstand a leakage current. It must also be able to withstand the toughest weather conditions. In Korea, porcelain insulators have been used widely. However, to make compact equipment and keep up with global trends, we have enhanced domestic production of polymer insulator and are encouraging its applications. Accordingly, this thesis will look at types of insulators, use and trends, and prospects of insulators application in the field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.85-88
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• 2003

In this study, porcelain insulator samples which have a different alumina composition were manufactured in order to test electrical and mechanical properties and make an analysis of the propagation phenomena of micro cracks on porcelain body. From XRD quantitative analysis the crystalline phases were different with alumina composition, sample C and D which have about 17wt% Corundum phase without the Cristobalite phase shows better electrical and mechanical properties than sample A and 8 which have the Cristobalite phase. In dielectrics test on porcelain samples with below 17wt% alumina composition, it was found that the amount of glass phase$(SiO_2)$have an main effect to decrease the dielectric loss$(tan{\delta})$, and the dielectric breakdown voltage of aluminous porcelain insulators was largely affected by its relative density. As a micro cracks analysis, HRS were measured, then the intensity of HRS increased with the amount of alumina composition. On the other hand, the propagation behaviors of cracks was fairly influenced by the distribution of pores.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.353-359
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• 2004

In this study. porcelain insulator samples which have a different alumina composition were manufactured in order to test electrical and mechanical properties and make an analysis of the propagation phenomena of micro cracks on porcelain body. From XRD quantitative analysis the crystalline phases were different with alumina composition, sample C and D which have about l7wt％ Corundum phase without the Cristobalite phase shows better electrical and mechanical properties than sample A and B which have the Cristobalite phase. In dielectrics test on porcelain samples with below l7wt％ alumina composition, it was found that the amount of glass phase(SiO$_2$) have an main effect to decrease the dielectric loss(tan$\delta$), and the dielectric breakdown voltage of aluminous porcelain insulators was largely affected by its relative density. As a micro tracks analysis, HRB were measured, then the intensity of HRB increased with the amount of alumina composition. On the other hand, the propagation behaviors of cracks was fairly influenced by the distribution of pores.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.58-65
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• 2018

The life span of the porcelain insulator was made to be 30 years, but currently many of the 154kV NGK porcelain insulators using in Korea are found to have passed the production life. Accidents caused by aged mechanical breakdown can lead to disruption of power supply in some areas, large economic losses, and casualties. Therefore, ultrasonic method, which is one of the non - destructive test methods, is applied as a method for evaluating the integrity of porcelain insulators. In this study, the experiment on the interface of cap was conducted and the difference between the energy difference and the attenuation coefficient of the reflected wave was derived according to the interface state of the steel - cement. The results of this study are expected to be used as the basic data of the ultrasonic testing to evaluate the interface condition of the porcelain insulator cap.

• JOURNAL OF ELECTRICAL WORLD
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• no.7 s.91
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• pp.22-37
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• 1984

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.255-257
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• 2003

The reliability of power transmission lines depends on long-term performance of the suspension insulators used on the lines. The importance of such long-term performance of the insulators has been recently noted, but its evaluation method has not been established yet. In this paper, various causes of insulator deterioration are verified and laboratory test method for evaluating the long term performance of insulators are studied.