• 한국안전학회지
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• 제27권4호
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• pp.13-19
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• 2012

The purpose of this study is to extract the major factors related to the deterioration mechanism of white organic light-emitting diodes(WOLED) by performing accelerated testing of temperature, voltage, time, etc., and to develop an accelerated life test(ALT) model. The measurement results of the brightness of the WOLED exhibited that their average brightness tended to increase as the operating voltage increased and that the half-life period of the brightness appeared after approximately 400 hours when the operating voltage was 20V and the ambient temperature was $85^{\circ}C$. It could be seen that although the WOLED showed comparatively the same brightness when the initial acceleration began after the operating voltage was applied to it, its brightness changed excessively after the WOLED's thermal storage had been made. In addition, it was observed that the half-life period was reduced as the ambient temperature and applied voltage increased. The strength of the WOLED which had been maintained in the range of visible light at the maximum load was reduced by the deterioration of the organic light emitting material due to the influence of the operating voltage and temperature, and the reduction of emitted light was small at low voltage and temperature. It could be seen that the failure of the WOLED during the ALT was caused by wear due to load accumulation over time, and that Weibull distribution was appropriate for the life distribution and acceleration was established between test conditions. From the WOLED analysis, it is thought that factors influencing the brightness deterioration are voltage, temperature, etc., and that comprehensive analysis considering discharge control, dielectric tangent margin, etc., would further increase the reliability.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.141-148
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• 2008

본 논문에는 22.9 kV-Y 배전계통의 1선 지락고장이 인체의 안전 및 저압설비의 보호에 대한 실험적 결과를 기술하였다. 새로이 제정된 KS C IEC 60364 규격군에 따른 고압 충전도체가 대지에 접촉되는 지락고장에 의한 위험전압과 저압기기의 스트레스전압을 평가하기 위해서 22.9[kV] 중성점 다중접지계통에 대한 실증실험을 수행하였다. 실험결과로부터 KS C IEC 60364 규격군을 기존의 국내배전계통에 적용할 때 부합되지 않는 중대한 문제점을 도출하였으며, 22.9 kV-Y 다중접지와 수용가설비접지를 공용하는 공통접지계통에서 발생하는 지락고장에 의한 일시적 과전압에 대한 효과적인 보호대책을 제시하였다. 결국 22.9 kV-Y계통과 저압설비를 공통접지로 하는 경우 인체와 저압설비의 안전을 위한 효과적인 보호대책의 구현에는 등전위본딩이 중요한 필수적 요건임이 밝혀졌다.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.890-894
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• 2011

In this thesis, the silicone filler with a sample size of 0~75 phr and void size of 2~4.5 mm is prepared in order to diagnose the defect of void which exists in widely used insulation material, silicone rubber. In this silicone rubber sample, electrodes are connected and whilst the voltage changes, applied voltage 7 kV~9 kV is increased constantly over time and discharge quantity, discharge frequency and applied voltage (T-QNV) were measured. The discharge quantity of the applied voltage (VQ) is measured to estimate inception voltage and extinction voltage. In addition, under the condition of maintaining constant applied voltage, discharge quantity and discharge frequency (QN) are measured, and its characteristics are analyzed.

• 전기학회논문지
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• 제65권1호
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• pp.232-238
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• 2016

This paper presents protection techniques against electric shock in low voltage DC(direct current) grounding systems depending on the analysis of earth fault current paths. Firstly, the comparison between alternating current and direct current on human was conducted, and current threshold values for each current path and for long duration were analyzed. Secondly, the analyses of the earth fault current flows were performed depending on the grounding types and earth fault conditions. Lastly, based on these analyses, adequate protection measures of electric shock depending on low voltage DC grounding types were provided.

• 한국수소및신에너지학회논문집
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• 제25권5호
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• pp.500-508
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• 2014

In the ongoing debates over the need to identify new sources of energy and to reduce the emissions of greenhouse gases. Hydrogen has emerged as one of the most promising alternatives due to its emissions from the vehicle being virtually zero. The governments have identified the development of regulations and standards as one of the key requirements for commercialization of HFCV. Regulations and standards will help overcome technological barriers to commercialization. The development of Global Technical Regulation (GTR) for HFCV occurred under the World Forum for Harmonization of Vehicle Regulations. Development of a technique for safety assessment of HFCV include four tasks, research for regulation system and policy, hydrogen safety, vehicle operation safety and protection against high-voltage. The objective is to establish a technique for safety assessment and amend safety standards for HFCV and consequently reflect research results to vehicle management policy. We devised safety standards and evaluation techniques with regard to high-pressure gas and high voltage of hydrogen fuel cell vehicle. KMVSS for HFCV was amended to June 10, 2014. including the results of the safety assessment technology for high-voltage and hydrogen characteristics.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.264-267
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• 2006

This paper describes the accident analysis by modeling the current transformer mounting in meaium voltage metal-clad switchgear(MCSG). In analyzing the accident the reconstruction at the current transformer mounting(VCB connecting guide) has to be taken into account. The accident was modelled as a 3-phase ground fault mounting between the end plate of a high voltage lines and the safety shutter at the current transformer mounting of the VCB inside the metal clad switchgear. Since the outside maintenance of the metal clad switchgear is restricted by the enclosed compartments, its circumference has to be kept clean. Through the reconstruction results, it was confirmed that the fault of the enclosed switchboard could be reduced when the shutter made of Fe material was changed into an insulation.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.78-83
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• 2010

The domestic 30AFs that are currently being produced show many problems due to different instantaneous trip characteristics in case of short-circuit. The troubles may cause explosion by excessive short-circuit capacities and arc emission, which results in a wide range of blackout. The function and safety of the low voltage circuit breakers installed before the end load are very important. This paper presents an idea on the safety improvement of the low voltage circuit-breakers through the analysis of instantaneous trip characteristics of domestic 30AF circuit-breakers.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.317-324
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• 2019

A high energy arcing fault event occurred in the medium-voltage (13.8 kV and 4.16 kV) metalclad switchgears in a nuclear power plant not only affecting switchgear but also connected equipment due to the arc energy. The high energy arcing fault also causes a fire that influences the safety function of the unit. Therefore, from the safety point of view, it is necessary to evaluate the influences of high energy arcing fault events on the safety functions of nuclear power plants. The purpose of this paper is to elaborate the characteristics of high energy arcing faults and propose a high energy arcing fault mitigation scheme for medium voltage networks in nuclear power plants.

• 한국안전학회지
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• 제30권3호
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• pp.26-31
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• 2015

This paper describes the characteristics of voltage drop and thermal for poor connection on electrical connector of circuit breaker in control box of small size pulverizer. In order monitor, we did the changes of RMS in voltage and temperature value with video and made normal state over $2.5N{\cdot}m$ and poor connections state below $0.2N{\cdot}m$ by screw gage. In case of voltage signal, the voltage drop was increased when the current was increased due to poor connections. In case of temperature signal, the temperature difference indicates ten times at 5A and fourteen times at 15A in the normal state. According to increase thermal energy, the insulation of electrical wiring and connector of circuit breaker can be carbonized. The results of this study will be useful to the development of preventive devices and system for electric fire by poor connection at small size pulverizer.

• 한국안전학회지
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• 제39권2호
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• pp.65-74
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• 2024

We analyzed the relationship between the normal measurement of the seismic accelerometer (SA) and the error rate of the output voltage linear ratio to propose an evaluation method to determine whether the SA in use is measuring normally. Utilizing a test bed, the regular operation of SA in use was evaluated using acceleration data measured through impact tests since there are no regulations regarding performance testing of SA in use. For the used SA, the error rate of the output voltage linear ratio, which is a major performance criterion, was evaluated. We analyzed common characteristics of the SA that satisfied the impact test and the performance criteria of the output voltage linear ratio error rate. The results indicated that we must consider the decreasing trend and convergence of the error rate as the measurement angle increases, ensuring that the average value of the output voltage linear ratio error rate is within 1%.