• Title/Summary/Keyword: Damaged cause

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The Mechanical and Electrical property changes of Overhead Conductor due to Forest Fire and Agents (산불과 소화약제에 노출된 가공송전선의 기계적 및 전기적 특성 변화)

  • Jang, Young-Ho;Kim, Byung-Geol;Kim, Shang-Shu;Han, Se-Won;Kim, Jin-Han
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.459-460
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    • 2008
  • Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very much important to maintain transmission line safely. Oxidation of overhead conductor was increased with temperature and time(maximum time : 30min). Conductivity of Al conductor was decreased by Agents. The detailed will be given in the text.

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Study on the corrosion of A/C condenser in the ship (선박용 해수 열교환방식 A/C 응축기의 부식원인)

  • Baek, S.M.;Yang, J.H.;Kim, K.J.;Moon, K.M.;Lee, M.H.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.283-284
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    • 2006
  • The ship performs heat exchange using seawater to keep main engine and auxiliary machinery at optimum temperature. In heat exchanger, refrigerant located outside of copper tube is cooled by seawater flowing through inside of copper tube. On the other hand, seawater erosion and corrosion nay occasionally cause the corrosion of the copper tube in A/C(Air Conditioner) condenser. This corrosion of copper tube makes seawater and refrigerant mixed, seriously damaging A/C system. In this study, accordingly, the exact ive mechanism of the corrosion on the condenser entailing serious problems occasional is investigated through the electrochemical polarization experiments on the condenser's component materials. According to the experiments, the corrosive procedures on the copper tube was verified by the fact that passive film of the copper tube surface which is destroyed by the pressure of sucked seawater, is damaged by the corrosive ingredients in the seawater.

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Motorcycle Inspection Standards Development I (이륜자동차 검사기준 개발 I)

  • Lim, Jaemoon;Ha, Taewoong;Hong, Seungjun
    • Journal of Auto-vehicle Safety Association
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    • v.9 no.4
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    • pp.48-54
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    • 2017
  • This paper presents the motorcycle inspection standards development on the vehicle identification, engine and transmission, tyres and wheels, steering and suspension, and brake system. 187 real-world motorcycles are visually and mechanically inspected according to the developed inspection standards. The non-compliance rate of the vehicle identification is 20.3% and main causes are insecure, damaged, and not clearly visible number plate. The non-compliance rate of the brake system is 15.5% and main cause is failing to meet the brake performance requirements. The motorcycle inspections standards are improved reflecting 187 cases of real-world motorcycle inspection results.

A Study on Authoritativeness of Electric Fire by Activating of Fire Damaged MCCB (소손된 배선용 차단기 동작상태에 의한 전기화재 규명의 신뢰성에 관한 연구)

  • Lee, Jong-Hwa;Mun, Yong-Soo;Kong, Ha-Sung
    • Journal of the Korea Safety Management & Science
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    • v.11 no.2
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    • pp.87-94
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    • 2009
  • In the fire there are fusion signs and damage by fire, and insulation aging and carbonization of the electric wiring in the ignition spot because of special characteristic of the appliance in the electricity fire. Because of the physical factor applied in the damage of fire, the decision of ignition spot by eye investigation is insufficient. In this paper, the cause of electricity fire is researched. The focus is on the operation state of operated MCCB(Molded Case Circuit Breaker) at the time of electricity fire. Through grasping the operation principle of MCCB and the experiment, the state of MCCB after fire suppression is discriminated. The distinction possibility on the exist of electricity fire is proposed.

A study on the safety of the Environment Corrosion of Suspension Insulater of a Catenary Trolley Wire Systems (카테나리 전차선로 현수애자의 환경부식에 따른 안전성 연구)

  • Lee, Jae-Bong;So, Sun-Young
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.864-874
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    • 2007
  • Suspension insulator in Catenary Trolley Wire Systems must have two characteristics, electric insulation and mechanical endurance. Because suspension insulator is used in supporting and insulating position between power supply parts and earth conducted supporting parts. The insulator's electric characteristics can be influenced by surface pollution and damage from the environment such as humidity, dust, smoke, salt. etc. And, the insulating parts can be electrically short. These electrically damaged insulator can cause serious accidents that have far-reaching effect. So appropriate management basis of suspension insulator is needed. And we present appropriate cleaning and the changing period of suspension insulator on the basis of actual data.

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Analysis and Measurement of Rough Surface Temperature Rise in Lubricated Condition (거친 표면의 마찰온도 해석 및 온도측정 실험에 관한 연구)

  • Lee, Sang-Don;Cho, Yong-Joo
    • Tribology and Lubricants
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    • v.23 no.2
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    • pp.56-60
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    • 2007
  • The main object of this study is to compare the results that have been concluded by the experiment and to estimate the temperature rise that can cause the contacting surface to be damaged. The former studies are based on the Blok and Jaeger formula. By these formulas we assume that two of the contacted objects are a kind of semi-infinite solid and with this assumption we can make a temperature analysis. But this method doesn't consider lubrication conditions and the calculation time requires a lot of time in that we have to face many difficulties in measuring the actual temperature rise. In this study we combines the semi-infinite solid method and the finite volume method to analyze the temperature of the contacting surface. And we measure temperature rise of the contact surface by dynamic thermocouple.

Behavior Study of Overhead Conductor due to Forest Fire and Agents (소화약제 및 산불에 노출된 가공송전선의 거동 변화)

  • Jang, Young-Ho;Kim, Byung-Geol;Kim, Shang-Shu;Han, Se-Won;Kim, Jin-Han
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1207-1208
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    • 2008
  • Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very much important to maintain transmission line safely. Especially, this paper describes the changes of mechanical and electrical properties of conductor due to forest fire and agents. The detailed will be given in the text.

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Cracking Behavior of Cement and Concrete Damaged by High Temperature of 800℃ (800℃ 조건에서의 시멘트 경화체의 균열 특성)

  • Ji, Woo-Ram;Park, Ji Woong;Shin, Ki Don;Lee, Gun-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.26-27
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    • 2017
  • In this study, the cracking characteristics of cured pastes at 800℃ were investigated by X-ray CT. The test specimens were fabricated with and without aggregate, and the heating rate condition was applied at rapid heating (10.0℃/min). It is considered that the rapid heating condition does not cause a temperature gradient phenomenon because the temperature difference between the surface and the center of the sample is small due to a low heating rate unlike an actual fire. The cracking condition of the specimens without aggregate was more severe than that of specimens with aggregate.

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The Analysis of Vibration with Pump and Pipe for Intake Station (취수장용 펌프 및 배관 진동 분석 사례)

  • Choi, B.K.;Choe, C.R.;Kim, H.J.;Gu, D.S.;Jung, H.Y.
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.200-204
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    • 2005
  • A few intake stations have vibration problems caused by pumps, motors and pipes. The vibration transffered from pumps, motors and pipes excites buiding severely. Therefore, the crack is generated on building wall and people who work at intake station are damaged. In this paper, the vibration and noise have been measured and analyzed for pumps, motors, pipes and building at intake station. Also, the cause of vibration and noise is identified. Finally, the reference of vibration and noise is established using results of measurement.

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Operation and Improvement Cases of FGD Non-leakage Type Gas-Gas Heater(GGH) for Coal Fired Power Plants (석탄화력 탈황설비 Non-leakage Type Gas-Gas Heater(GGH) 운영 및 개선사례)

  • Seong, Kijong;Lee, Changsik
    • Journal of the Korean Society of Combustion
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    • v.22 no.4
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    • pp.35-42
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    • 2017
  • This case covers the issues related to the operation problem, cause analysis and improvement cases of the FGD that employed the non-leakage type GGH in coal-fired power plant for the first time in Korea. In the Cooler, there was a main problem that the tube is damaged by the ash cutting due to the high velocity of flue gas in the duct and by the weak wear resistance of material. In the Reheater, there was a main problem that the tube was corroded due to chlorine and sulfur in the circumstance of the low temperature. In order to solve those problems, we have improved the Reheater tube and tube fins by coating enamel to reduce corrosion rate.