• Fire Science and Engineering
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• v.18 no.3
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• pp.45-50
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• 2004

Thermal degradation of PVC which used for insulator of 600V vinyl insulated wire has been studied by thermo gravimetry analysis and accelerated thermal aging test. The activation energy using thermo gravimetry analysis was determined by the kinetic methods, such as Kissinger and Flynn-Wall-Ozawa. The activation energy was determined to from 89.29 kJ/mol to 111.39 kJ/mol in 600V PVC insulated wire and from 97.80 kJ/mol to 119.25 kJ/mol in 600v heat-resistant PVC insulated wire. And also, the activation energy through a long-term thermal aging test was calculated by using Arrhenius equation In the low temperature of 8$0^{\circ}C$, 9$0^{\circ}C$, 10$0^{\circ}C$. The results showed that 600V PVC insulated wire was 92.16 kJ/mol, and 600v heat-resistant PVC insulated wire was 97.52 kJ/mol. Consequently, the activation energy of 600V heat-resistant PVC insulated wire is larger than 600V PVC insulated wire. Therefore, it can be predicted that 600V heat-resistant PVC insulated wire has a long-term stability relatively.

• Korean Journal of Materials Research
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• v.12 no.2
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• pp.103-111
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• 2002

The thermally insulated underground pipelines have been used for district heating system. The sensor wire embedded in the insulation was used for monitoring the insulating resistance between the sensor wire and the pipe. The resistance measurement system detects corrosion of steel pipe under insulation. The corrosion and stress corrosion cracking(SCC) characteristics of sensor wire in synthetic ground water were investigated using the electrochemical methods and constant load SCC tests. The polarization tests were used to study the electrochemical behavior of sensor wire. The sensor wire was passivated at temperatures ranging from 25 to $95^{\circ}C$. However, the applied sensing current larger than passive current resulted in breakdown of passive film. The constant load SCC tests were performed to investigate the effects of applied current and load on the fracture behavior. Stress-corrosion cracks initiated at pits that were produced by sensing current. The growth of the pit involves a tunnelling mechanism, which leads to ductile fracture.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.2
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• pp.1-8
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• 2024

Bonding wires are composed of conductive metals of Au, Ag & Cu with excellent electrical conductivities for transmitting power and signals to wafer chips. Wire metals do not provide electrical insulation, adhesion promoter and corrosion passivation. Adhesion between metal wires is extremely weak, which is responsible for wire cut failures during thermal cycling. Organic coating for electrical insulation does not satisfy bondability and manufacturability, and it is complex to apply very thin organic coating on metal wires. Automotive packages require enhanced reliability of packages under harsh conditions. LED and power packages are susceptible to wire cut failures. Contrary to conventional OCB behaviors, forming gas was not required for free air ball formation for both Ag and Pd-coated Cu wires with Al₂O₃ passivation.

• Fire Science and Engineering
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• v.15 no.1
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• pp.108-115
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• 2001

In this paper, we analyzed the properties change of electric wire when the thermal stress was applied to 600V grade polyvinyl chloride insulated wire (IV). In the structure analysis, normal wire has the properties of direction on the surface, but in case of deteriorated wire at above $400^{\circ}c$, it formed the carbide, the crack and the crystal. The surface composition rate of normal wire was Cu : 100%, but the section composition of the deteriorated wire at $800^{\circ}c$ showed Cu : 78.89%, O : 21.11%. In result of analyzing the differential scanning calory of copper wire, the new reaction peak was observed on the deteriorated wire at above $700^{\circ}c$. In case of the deteriorated wire as $150^{\circ}c$ at the differential thermal analysis, an endothermic reaction appeared at $264^{\circ}c$ lower than the reactive point of normal wire. The occupation rate of oxygen according to the deterioration of copper wire is about 20% at $500^{\circ}c$.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1601-1602
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• 2011

전 세계적으로 매년 증가하고 있는 전력수요는 높은 부하밀도와 함께 송전계통의 대용량화를 필요로 하고 있다. 단순히 송전회전의 증가를 통한 송전계통의 대용량화는 비용의 증가를 초래하며, 과밀화된 도심에서의 경과지 확보와 환경적인 악영향에 대한 우려 등으로 어려움에 직면하고 있다. 따라서, 높은 부하밀도의 수용가가 집중된 송전계통의 대용량화는 보다 적은 비용과 환경적 영향을 고려하여 지중송전 케이블의 적용이 필요하며, 이러한 특수목적의 송전을 위하여 고효율, 대용량화의 여러 기술이 연구 개발되어 적용 중이며, 일부 기술은 상용화 단계에 있다. 본 논문은 지중송전 케이블의 대용량화 기술 중에 도체의 교류저항을 저감하여 저손실과 대용량 송전이 가능한 소선절연도체(Conductor with insulated wires 또는 Enamelled wires)의 개발과 설치공사에 대하여 기술하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.8-12
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• 2000

The properties variation by deterioration of the 600V grade heat-resistant polyvinyl chloride insulated wire(HIV) was analyzed. The weight variation of the thermal deteriorated HIV was about 42% at 80$0^{\circ}C$ and over. From the analysis result of the metallurgical microscope photographs it shows that the sorface of normal wire showed the elongated structures. However the elongated structures did not appear at $900^{\circ} and over and we could observe that particles were grown. The grown oxidized substances in the thermally deteriorated electric wire were observed by SEM. The CuL, CuK, $CuK_b$, OK and CIK spectra of the thermally deteriorated HIV at $300^{\circ}C$ were uniform regardless of the scanning length, but the spectra of CIK could not found at above $700^{\circ}. At the DTA analysis, the endothermic reactions were occurred around $3006{\circ}C\; and\; 400^{\circ}C$ and the exothermic reactions were occurred around $470^{\circ}, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.907-911
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• 2007

This paper dealt with the frequency spectrum analysis of acoustic signal produced by partial discharge (PD) in insulation oil and the positioning of PD occurrence to apply in diagnosis of oil insulated transformers. Three types of electrode system ; the needle-plane, the plane-plane, and the wire-wire structure were assembled to simulate partial discharges in oil insulated transformers. A low-noise amplifier and a decoupling circuit were designed to detect acoustic signal with high sensitivity The frequency spectrum of the acoustic signal were 50 kHz ${\sim}$ 260 kHz in the needle-plane, 50 kHz ${\sim}$ 250 kHz in the plane-plane, and 45 kHz${\sim}$195 kHz in the wire-wire electrode system. Their peak frequencies were 145 kHz, 130 kHz and 114 kHz, respectively The position of PD occurrence was calculated by the time difference of arrival (TOA) using three acoustic emission (AE) sensors, and we could find the position within the error of 1 % in the experimental apparatus.

• Fire Science and Engineering
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• v.32 no.2
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• pp.48-56
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• 2018

This paper reports the results of a study on the over-current characteristics of IV insulated wire sheath according to accelerated degradation. In order to examine the degradation of a IV insulated wire sheath through insulation, acceleration degradation experiments were performed using the Arrhenius equation of acceleration life test models; test samples with equivalent lives of 0, 10, 20, 30 and 40 years were prepared. Then allowed currents with over-current of 100%~500% were introduced to measure the times of first generation of smokes and carbonization in the wire sheath, and it was found that the times of first generation of smokes and carbonization in the wire sheath decreased as the equivalent life increased. In more detail, when 270% over-current is applied, the electrical fire risk of equivalent life of 40 years increased by approximately 3.2 times based on equivalent life of 0 years. Also, when the over-current was 255% and 260%, carbonization occurred only in the equivalent life of 40 years, and the fire risk according to the accelerated degradation was increased dramatically. In addition, FT-IR and SEM analyzes were used to confirm the characteristics and surface changes of IV insulated wire sheath according to the equivalent life.

• Fire Science and Engineering
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• v.34 no.3
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• pp.8-17
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• 2020

In this study, the characteristics of HFIX insulated wire sheaths contaminated by pollutants were examined. KS C IEC 60811-1-3 standard was followed in performing the water-resistance wire tests. Pollutants were selected, and the specimens were exposed to the pollutants for a maximum duration of four weeks. The maximum tensile load and the elongation rate were measured each week. As the period of pollution exposure increased, the maximum tensile load of the specimens decreased by 6.22% and 6.52% at room temperature and high temperature, respectively, and 19.94% for specimens coated with a rust-proof lubricant. The elongation rate also decreased rapidly, such that the reductions in the properties of the sheath were significant. From the analysis of the surfaces using a scanning microscope, as the contamination period increased, structural changes such as perforation, split, and melting occurred, and the mechanical properties of the specimens decreased. Therefore, it is necessary to develop and follow an inspection cycle and periodically carry out repairs to prevent the deterioration of insulated wires.

• Fire Science and Engineering
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• v.33 no.2
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• pp.114-123
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• 2019

The paper relates to a study on the changes in performance of insulation sheath resulting from accelerated degradation of IV and HIV insulated wire. To assume insulation degradation of IV and HIV insulated wire, accelerated life tests using Arrhenius equation were conducted among accelerated life test models, and experimental samples of 0 year, 10 years, 20 years, 30 years, and 40 years in equivalent life were produced. Whereas the maximum tensile load were increased as accelerated degradation of IV and HIV insulated wire progressed, elongation percentage, rupture time, and flexibility of insulated wires were found to be gradually reduced. According to the additional surface analysis results for the insulated wires per equivalent life using a scanning electron microscope, mechanical properties of the insulator were observed to be reduced as insulation degradation resulting from aging progressed since phenomena such as formation of crystalline structures and perforation, etc. occurred on the sample surface with progression of accelerated degradation. Consequently, institutional replacement of insulated wires and preparation of repair times considering performance degradation of the insulator installed inside buildings are considered necessary in order to prevent in advance the risks of electrical fire resulting from degradation in insulation performance.