• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.891-893
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• 1992

Polymers have good electrical properties as an insulation material. Though they show more and less poor resistance to heat, radiation, and oxygen, the poor properties have been overcame by developing new resin with the saturated molecular structure and compounding resin with resistive fillers. Polymer insulators have many advantages; light weight, good mechanical properties, better contaimination performance, low cost by mass productivity, no destruction in many pieces, good flexibility in design, short manufacturing time. Usage of polymer insulators has increased rapidly with good credit on long term properties in advanced nations and will continue to grow.

• 대한전기학회논문지
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• 제40권12호
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• pp.1242-1251
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• 1991

This paper is to investigate the tree growth phenomena and the characteristics of $\varepsilon$' and tan$\delta$ for the effect of ultrasonic wave on polymer insulation material. The conclusions are as follows. 1) As the pressure amplitude of ultrasonic wave is larger and its irradiated time is longer, tree inception voltage and its breakdown voltage in specimen are smaller, and tree growing is faster. 2) As the irradiated quantity of ultrasonic wave is more increased, the value of tan$\delta$ is larger, but the value of $\varepsilon$' is almost constant. 3) The effect by the pressure amplitude of ultrasonic wave is greater than that by its irradiated time on the insulation characteristics of polymer material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.275-275
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• 2010

나노하이브리드 방법으로 제조된 변성 폴리이드계 나노하이브리드 절연코팅의 표면 내열특성을 비교 분석하였다. 최근 절연코팅의 사용환경이 열적내구성을 높게 요구하는 경향이 크다. 따라서 이러한 환경에 맞는 절연성과 열적내구성을 구현하기 위해서는 열적내구성이 우수한 세라믹 일자를 수지에 분산시켜 그 성능을 개선할 필요가 있다. 본 논문에서는 나노 하이브리드 방법으로 제조된 변성 폴리이드계 나노하이브리드 절연코팅의 표면 내열특성을 비교 분석하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.46-49
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• 1994

In order to investigate possibility of CV cable diagnosis technique, residual insulation characteristics of .long - term serviced 0.6 kV CV Cable are examined by DC leakage current residual voltage tensile strength, cross1inking density and AC & impulse breakdown. Also effect of cable structure and water tree are reported

• Transactions on Electrical and Electronic Materials
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• 제16권5호
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• pp.260-263
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• 2015

Epoxy/micro-sized alumina composite was prepared and the effects of alumina content on the electrical and mechanical properties were investigated in order to develop an insulation material for gas insulated switchgear (GIS). Nano-sized alumina (average particle size: 30 μm) was also incorporated into the epoxy/micro-sized alumina composite. An electrical insulation breakdown strength test was carried out in sphere-sphere electrodes and the data were estimated by Weibull statistical analysis. Tensile strength was measured at a crosshead speed of 10 mm/min using a universal testing machine. Alumina content was varied from 0 wt% to 70 wt%.). As micro-sized alumina content increased, insulation breakdown strength increased until 40 wt% alumina content and decreased after that content. The tensile strength of a neat epoxy system was 82.2 MPa and that value for 60 wt% alumina content was 91.8 MPa, which was 111.7% higher than inthe neat epoxy system. The insulation breakdown strength of micro-sized alumina (60 wt%)/nano-sized alumina (1 phr) glycerol diglycidyl ether (GDE) (1 phr) composite was 54.2 MPa, which was 116% higher than the strength of the system without nano-sized alumina.

• 한국전기전자재료학회논문지
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• 제34권2호
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• pp.136-141
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• 2021

Heating cables, widely used in office buildings, factories, streets and railways, deteriorate in electrical insulation during operation. The insulation deterioration of heating cables leads to electric discharges that can cause electrical fires. With this background, this paper dealt with a condition monitoring technique for heating cables by the analysis of discharge signals to prevent electrical fires. Insulation deterioration was simulated using an arc generator specified in UL1699 under AC operation, and the characteristic and propagation of discharge signals were analyzed on a 100 meter-long heating cable. Discharge signals produced by insulation deterioration were detected as a voltage pulse because they are as small as a few mV and they are attenuated through propagation path. The frequency spectrum of discharge signals mainly existed in the range from 70 kHz to 110 kHz, and the maximum attenuation of the signal was 84.8% at 100 meters away from the discharge point. Based on the experimental results, a monitoring device, which is composed of a high pass filter with the cut-off frequency of 70 kHz, a comparator, a wave shaper and a microprocessor, was designed and fabricated. Also, an algorithm was designed to discriminate the discharge signal in the presence of noise, compared with the pulse repetition period and the number of pulse counts per 100ms. In the experiment, the result showed that the prototype monitoring device could detect and discriminate the discharge signals produced at every discharge point on a heating cable.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.234-235
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• 2006

In this study, we experimented deterioration characteristics of PVC insulation wires for electrical apparatus by series arcing and analyzed the heat generation at the contacts of wires, glowing/growing process of copper oxide, waveforms of contact voltage, current, power dissipation, and so on. We found out that how glowing contacts and surface arcing can decompose PVC insulation and that subsequent series arc can lead to ignition. We expect that these results are useful for improving fire protection technology by providing a better understanding of how electrical fires can initiate.

• E2M - 전기 전자와 첨단 소재
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• 제9권5호
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• pp.483-489
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• 1996

Power transformer have many unsymmetrical structure and electric field is enhanced in that area. Those unsymmetrical area are not covered oftenly by solid insulating material which is used as a framework specially in gas transformer. By that result there is a possibility to decrease the total insulation class of the transformer. So in this study the electrical characteristic of $FC+SF_6$ mixture gas which is used as coolants for large power gas insulated transformer and its effects on electrical characteristics of structural material are investigated. Also breakdown characteristic with the tension of taping and curvature of the coil are studied which could be used as a design factor of large power transformer.

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1299-1304
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• 2003

Fault current limiters (FCL) are extensively needed to suppress fault currents, especially for trunk power systems heavily connected to high voltage/large current transmission lines. Due to its ideal electrical behavior, high-temperature superconductor fault current limiter (HTSFCL) becomes one of the most important developing trends of limiters in power system. This paper describes the result of an investigation of the dielectric characteristics of turn-to-turn insulation for pancake and solenoid type reactor coil in liquid nitrogen. The influence of thickness in a variety length, on AC, DC and impulse surface flashover has been investigated. Also, the relationships between the number of turn and breakdown characteristics were clarified. The information gathered in this test series should be helpful in the design of liquid nitrogen filled DC reactor type HTSFCL.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.542-543
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• 2005

In this paper, describes the fabrication and dielectric insulation characteristics experimental results of the model cable for the 22.9kV class HTS power cable. The model cable were tested with partial discharge(PD), AC and impulse withstand voltage in liquid nitrogen($LN_2$) and liquid nitrogen pressure. In these test results, PD inception stress and AC, impulse breakdown strength increase as the pressure of the liquid nitrogen increases.