• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.200-202
• /
• 2004

Characteristics of the break down current of HTS tape with different insulator are described. The various insulators are utilized for enduring the high voltage in superconducting power devices. The break down current of HTS tape largely depends on insulators wound round HTS tape. In this research, The break down currents of Bi-2223 tape, which is widely used for superconducting power devices are tested and discussed. It is expected that results from this study can be utilized as basic data in designing superconducting power devices.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.233-236
• /
• 2004

Recently, the polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. The shape design of porcelain insulator is formalized but design standard for polymer insulator is no standardized up to now, much research is necessary in real condition. In this paper, the surface and tracking properties of polymer suspension insulator for power transmission is investigated with ICP-AES, SEM, EDX, tracking wheel test and flashover voltage test. The diagnosis of insulator sample in tracking test hass been analyzed by leakage current STRI Guide and thermal image.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.12
• /
• pp.162-168
• /
• 2009

This paper describes a study that is to redesign insulation of transmission lines and determine required the numbers of insulators in order to enhance the insulation performance of existing transmission lines which were constructed with standard insulation design, considering overvoltage analysis results, probabilities and characteristics of faults. To ensure proper insulation distance without deteriorating the required performance, EMTP model is established to calculate maximum overvoltage in the line. The fault records and predicted outage rates due to lightning and contamination in the line were investigated and analyzed respectively. It presents a method to determine the numbers of insulators considering the probability and the characteristic of fault.

• Congress of the korean instutite of fire investigation
• /
• 2010.06a
• /
• pp.43-55
• /
• 2010

In this study, the risk on the contamination of the bracket insulators were investigated and surface discharge process leading to the fire is verified. If the insulator surface is coated by the grease, dust and contaminants likely to be attached. Leakage current to flow easily. In these results, the improvement of three methods have been proposed for the apply to the field. It is very important to ensure the safety for the service of electrical safety. For the public service, it's important to safety of railroad. Through this study, it is expected to be safer.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.4
• /
• pp.899-904
• /
• 2011

Inspections and diagnoses of corona discharge are important in order to prevent electrical faults of external insulation in power systems. This paper studies a measurement of ultra-violet rays(UV) strength of corona discharges on insulators using a UV sensor with an optic lens. The data has been compared with the images of a UV camera. The UV sensor estimated that DC voltage needed to be set at 700V for accurate data analysis of the properties of UV detected during corona discharge. UV was generated at 60kV when the corona discharge occurred. UV strength and images of UV increased at a high voltage. The image area of the UV using a UV camera and the detection of UV using a UV sensor have shown, that the polymer insulator mounted on a live part must be checked when the applied voltage on the good polymer insulator is greater than 37.5% of its breakdown voltage.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.4
• /
• pp.961-968
• /
• 2016

The non-uniform distribution of contamination on insulator surface has appreciable effects on flashover voltage, and corresponding researches are valuable for the better selection of outdoor insulation. In this paper, two typical types of porcelain and glass insulators which are widely used in ac lines were taken as the research subjects, and their corrections of AC flashover voltage under non-uniform pollution were studied. Besides, their flashover characteristics under different ratio (T/B) of top to bottom surface salt deposit density (SDD) were investigated, including the analysis of flashover voltage, surface pollution layer conductivity and critical leakage current. Test results gave the modified formulas for predicting flashover voltage of the two samples, which can be directly applied in the transmission line design. Also, the analysis delivered that, the basic reason why the flashover voltage increases with the decrease of T/B, is due to the decrease of equivalent surface conductivity of the whole surface and the decrease of critical leakage current. This research will be of certain value in providing references for outdoor insulation selection, as well as in proposing more information for revealing pollution flashover mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07a
• /
• pp.469-472
• /
• 2004

There have been numerous accelerated aging laboratory tests for evaluating suitability of polymeric materials and devices. Aging test for materials and its full scale device has been conducted, but poor correlation of aging test such as service experience were observed. Service experience plays a key role in the utility section of composite insulators. A meaningful and reliable accelerated aging test is needed for evaluating composite insulator. During the service these insulators are subjected to aging stress such as humidity, pollution, and electrical field, and erosion and tracking of the weathershed occurs. This paper presents the criteria of reliability evaluation and evaluation facilities for 22.9 kV suspension composite insulator. We adopt the criteria of reliability evaluation consist of two test methods. One is CEA tracking wheel test for examining the tracking and erosion performance of composite insulator. The other is multi-stress aging test for examining effects of environmental factors such as UV, temperature, humidity, etc on composite insulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.539-542
• /
• 2003

Recently, the polymer insulators which are being used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination which lead to the well known phenomenon of dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. The shape design of porcelain insulator is formalized but design standard for polymer insulator is no standardized up to now, much research is necessary in real condition. In this paper, the aging property of polymer insulator with shed shape(regular, alternative type) is analyzed through numerical analysis, CEA(canadian electricity association) tracking wheel test and IEC 61109 Annex C.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.79-80
• /
• 2006

본 논문에서는 초고압전력용 케이블에서 절연재료로 사용되고 있는 가교폴리에틸렌 내부(XLPE)에 침투된 침전극의 기울기변화에 따른 XLPE의 전계분포를 경계요소법에 의한 3차원 시뮬레이션 프로그램을 통하여 해석하여, 약 $20^{\circ}$의 기울기에서 전계가 집중되는 현상을 확인하였다.

• Transactions on Electrical and Electronic Materials
• /
• v.9 no.5
• /
• pp.186-192
• /
• 2008

Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at $25^{\circ}C$ to $80^{\circ}C$ and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at $80^{\circ}C$ to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved $0^{\circ}$ and $180^{\circ}$ at the positive region and $180^{\circ}$ and $360^{\circ}$ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.