• 제목/요약/키워드: underground temperature

검색결과 616건 처리시간 0.031초

온도의존성 항목을 고려한 지중배전케이블의 허용전류 계산에 관한 연구 (A Study on the Current-Carrying Capacity Calculation Considering the Temperature-Dependant Factors in Underground Distribution Cables)

  • 정성환;김대경;최상봉;배정효;하태현;이현구;장완성;김숙철;김태현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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    • pp.141-143
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    • 1999
  • This paper has studied on a calculating method of a current carrying capacity considering the temperature-dependent factors in underground distribution cables and proved its efficiency of the temperature equation.

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지중 전력케이블용 반도전재료의 이온성 불순물에 따른 흡습 및 열적특성 (Absorption and Thermal Properties According to Ionic Impurities of Semiconductive Materials for Underground Power Cable)

  • 이경용;최용성;박대희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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    • pp.133-137
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    • 2004
  • In this paper, we investigated impurities content, absorption properties, and thermal properties showing by changing the content of carbon black which is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens and absorption properties were measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer) and Karl Fisher. And high temperature, heat degradation initiation temperature, and heat weight loss were measured by TGA (Thermogravimetric Analysis). The dimension of measurement temperature was 0$[^{\circ}]$ to 800$[^{\circ}]$, and rising temperature was 10$[^{\circ}/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result also absorption amount was increased according to these properties. Specially, impurities content values of the A1 and A2 of existing resins were measured more than 4000[ppm]. Heat degradation initiation temperature from the TGA results was decreased according to increasing the content of carbon black. All over, heat stabilities were EEA>EBA>pEVA. That is, heat stabilities of EVA containing the weak VA(vinyl acetate) against heat was measured the lowest.

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Intelligent cooling control for mass concrete relating to spiral case structure

  • Ning, Zeyu;Lin, Peng;Ouyang, Jianshu;Yang, Zongli;He, Mingwu;Ma, Fangping
    • Advances in concrete construction
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    • 제14권1호
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    • pp.57-70
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    • 2022
  • The spiral case concrete (SCC) used in the underground powerhouse of large hydropower stations is complex, difficult to pour, and has high requirements for temperature control and crack prevention. In this study, based on the closed-loop control theory of "multi-source sensing, real analysis, and intelligent control", a new intelligent cooling control system (ICCS) suitable for the SCC is developed and is further applied to the Wudongde large-scale underground powerhouse. By employing the site monitoring data, numerical simulation, and field investigation, the temperature control quality of the SCC is evaluated. The results show that the target temperature control curve can be accurately tracked, and the temperature control indicators such as the maximum temperature can meet the design requirements by adopting the ICCS. Moreover, the numerical results and site investigation indicate that a safety factor of the spiral case structure was sure, and no cracking was found in the concrete blocks, by which the effectiveness of the system for improving the quality of temperature control of the SCC is verified. Finally, an intelligent cooling control procedure suitable for the SCC is proposed, which can provide a reference for improving the design and construction level for similar projects.

지중 송전 케이블 선로임피던스 계산 및 실측 (The line impedance calculation and measurement of the underground transmission cable)

  • 김남열;김정년;허회덕;이수길
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
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    • pp.405-407
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    • 2006
  • The power system analysis based on the accurate impedance of the individual underground cable, which is the inter connected to a large power system, is required. A study on calculation method of impedance allowable current for underground cables. furthermore, various methods of bonding and earthing the sheath have been used for the purpose of eliminating or reducing the sheath losses. the effectes of bonding and earthing must be includied in impedances. therefore, the subject of predicting thermal performance of soil and cable systems has been received increasing attension. for these problems, this paper describes a general formulation of impedance that is based on the effect of crossbonding and earthing of the sheath on the 66kV, 132kV and 220kV underground cable systems. also the work is presented, for calculating the temperature rise of power cable and soil.

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터널 화재로 인한 콘크리트 세그먼트의 손상특성 규명 (Fire-induced damage on Shield TBM concrete segment)

  • 최순욱;장수호;이규필;배규진
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.423-430
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    • 2005
  • Fire accidents in underground space may bring much loss of lives as well as properties and result in catastrophic disasters. This study aimed to manufacture the high-temperature furnace capable of simulating fire scenarios (RABT and RWS) and carry out the preliminary fire tests to evaluate fire-induced damage in underground structures. Specimens used in the fire tests were the concrete segments generally used in shield TBM tunnels. The simulated fire scenario was set to the RABT curve that is the most representative fire scenario in underground space. From the fire tests, the spalling was estimated to reach approximately 20cm from the surface exposed to fire. In addition, from the observation of core specimens obtained after fire tests, the deteriorated zone of unspalled specimens amounted to approximately 10cm from the surface of spalling.

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수도권 지하철 지하역사의 실내공기질 연구 (Study on the Air Quality of Metropolitan Subway Stations)

  • 조영민;박덕신;박병현;박은영
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 춘계학술대회 논문집
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    • pp.77-82
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    • 2005
  • Recently, people's rising interests toward a 'well-being' lifestyle together with research contributions are accelerating the concerns regarding indoor air pollution making indoor air quality management an emerging environmental challenge of the era. The Ministry of Environment began to regulate the air quality of railway stations last year. The newly established 'Indoor Air Quality Act' covers 17 facilities whereas only underground subway stations and underground markets were regulated by previous 'Underground Air Quality Management Act' of 1996. In this study, we carried out the measurement of temperature, relative humidity, CO(carbon monooxide), $CO_2$(carbon dioxide), HCHO(formaldehyde), PM-10(particulate matters), and VOCs(volatile organic compounds) in underground subway stations. Based on the obtained results, we will suggest a way to improve the indoor air quality of the subway stations.

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공동주택 지하주차장의 풍력환기 성능에 관한 연구 - 환기구 면적 및 주변건물의 영향 - (A Study on Ventilation Performance driven by Wind Force in Underground Parking Lots of Apartment - Influence of Opening Size and Surrounding Building -)

  • 노지웅
    • KIEAE Journal
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    • 제12권1호
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    • pp.29-34
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    • 2012
  • As a series of studies about natural ventilation driven by wind in basement parking lots of apartment, the influence of opening size and surrounding buildings on ventilation rate was analyzed. Natural ventilation in underground parking lots almost rely on wind than temperature difference. To investigate natural ventilation driven by wind, wind tunnel tests by using scale model and tracer gas method were conducted. $CO_2$-gas concentration was measured, natural ventilation rates were calculated. The experimental results showed that the natural ventilation rate is more reliable to wind direction and surrounding building than opening size and distance between buildings. It was verified that surrounding buildings play a principal role in increasing air flow rate by accelerating wind speed, and growing turbulence intensity. And it showed that ventilation performance is able to be increased by oblique wind to entrance ramp than head on wind in underground parking lots with surrounding buildings.

DTS를 활용한 광복합 지중 배전계통 실시간 감시시스템 개발 및 성능평가 (A Development and Performance Assessment of On-Line Monitoring System for Optical Fiber Composite Underground Distribution Network using DTS)

  • 조진태;김주용;이학주;조휘창;최명호
    • 조명전기설비학회논문지
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    • 제25권6호
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    • pp.115-121
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    • 2011
  • Intelligent distribution equipment is inevitable to realize self-healing which is one of smart grid functions in distribution network. Therefore, most of distribution equipment have been developed with self diagnostic sensors. However, it is not effective to construct on-line monitoring system for underground distribution cable because of high cost and low sensitivity. Recently, optical fiber composite cable is being considered for communication and power delivery in order to cope with increasing communication in distribution network. This paper presents the design and performance assessment results of underground cable on-line monitoring system using DTS(Distributed Temperature Sensing) and optical fiber composite underground cable.

터널 및 지하구조물의 내화특성에 관한 연구 (A Study on Fire Resistance Character of a Tunnel and an Underground Structure)

  • 유상건;김정주;박민용;김은겸;이준석
    • 한국철도학회논문집
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    • 제13권2호
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    • pp.194-200
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    • 2010
  • 최근 지하철 시공 확대와 국토의 지형적인 특수성, 시공기술의 발달 등으로 인하여 장대터널이 증가하고 있는 실정이다. 터널 및 지하구조물에서 발생되는 화재는 지하공간이라는 폐쇄된 공간특성으로 인해 지상화재에 비해 많은 인명과 경제적 피해를 발생시킨다. 국내의 경우 터널 및 지하구조물에 대한 내화 연구가 진행 중이나 고온 시 콘크리트의 폭열 발생으로 인한 내하력 저하 및 안전성 평가에 대한 연구가 부족한 실정이다. 따라서 본 연구에서는 시간가열 온도곡선(RABT 및 RWS)에 따른 콘크리트 내화 특성을 평가하고 실제 발생한 화재사례와 비교 검토하여 적용성을 제시하였다. 또한 유한요소 기반의 수치모델을 적용한 열-역학 연동해석을 실시하여 화재로 인한 지하구조물의 단면 손실 및 손상정도를 예측 평가하였다.

Performance monitoring of timber structures in underground construction using wireless SmartPlank

  • Xu, Xiaomin;Soga, Kenichi;Nawaz, Sarfraz;Moss, Neil;Bowers, Keith;Gajia, Mohammed
    • Smart Structures and Systems
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    • 제15권3호
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    • pp.769-785
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    • 2015
  • Although timber structures have been extensively used in underground temporary supporting system, their actual performance is poorly understood, resulting in potentially conservative and over-engineered design. In this paper, a novel wireless sensor technology, SmartPlank, is introduced to monitor the field performance of timber structures during underground construction. It consists of a wooden beam equipped with a streamlined wireless sensor node, two thin foil strain gauges and two temperature sensors, which enables to measure the strain and temperature at two sides of the beam, and to transmit this information in real-time over an IPv6 (6LowPan) multi-hop wireless mesh network and Internet. Four SmartPlanks were deployed at the London Underground's Tottenham Court Road (TCR) station redevelopment site during the Stair 14 excavation, together with seven relay nodes and a gateway. The monitoring started from August 2013, and will last for one and a half years until the Central Line possession in 2015. This paper reports both the short-term and long-term performances of the monitored timber structures. The grouting effect on the short-term performance of timber structures is highlighted; the grout injection process creates a large downward pressure on the top surface of the SmartPlank. The short and long term earth pressures applied to the monitored structures are estimated from the measured strains, and the estimated values are compared to the design loads.