• Title/Summary/Keyword: Failure line

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Study of an algorithm for intelligent digital protective relaying (지능형 디지탈 보호계전 알고리즘 연구)

  • 신현익;이성환;강신준;김정한;김상철
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.343-346
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    • 1996
  • A new method for on-line induction motor fault detection is presented in this paper. This system utilizes unsupervised-learning clustering algorithm, the Dignet, proposed by Thomopoulos etc., to learn the spectral characteristics of a good motor operating on-line. After a sufficient training period, the Dignet signals one-phase ground fault, or a potential failure condition when a new cluster is formed and persists for some time. Since a fault condition is found by comparison to a prior condition of the machine, on-line failure prediction is possible with this system without requiring information on the motor of load characteristics.

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A Simulation on the Displacement Stress of Cement in Porcelain Insulators for Transmission Line (송전용 자기재 애자의 시멘트 변위 응력에 관한 시뮬레이션)

  • Han, S.W.;Cho, H.G.;Woo, B.C.;Jung, G.C.;Lee, D.I.;Choi, I.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.476-479
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    • 2002
  • The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied the effect of cement displacement resulting environmental ageing parameters on porcelain insulator mechanical properties for transmission line by simulation (ANSYS/NASTRAN program) and test methods. These simulation analysis and experimental results show that cement volume growth affects severely to be mechanical failure ageing.

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A case study on the failure diagnosis of plant machinery system by implementing on-line wear monitoring (실시간 마모량 측정을 통한 대형 기계윤활시스템의 파손발생 진단사례)

  • 윤의성;장래혁;공호성;한흥구;권오관;송재수;김재덕;엄형섭
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.04a
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    • pp.321-327
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    • 1998
  • This paper presented a case study on the application of on-line wear monitoring technique to a high duty air-turbo-compressor system. Main objects monitored were a gear unit and metal bearings, both shown frequent troubles due to the severe operation conditions at heavy dynamic load. The air-turbo-compressor system needs secure condition monitoring because it is one of the main utilities in steel making industry. Temperature and vibration characteristics have been mainly on-line monitored in this system for a predictive maintenance; however, it has been shown that they are not fairly good enough to give an early warning prior to the machine failure. In this work, an on-line Opto Magnetic Detector(OMD) was implemented for an on-line wear monitoring, which quantitatively measured the contamination level of both ferrous and non-ferrous wear particles by detecting the change in optical density of used oil. Results showed that the application of on-line OMD system was satisfactory in diagnosis of the machine system.

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A study on lighting performance of 345[KV] model line (345[KV] 송전선로의 뇌방호 실패의 예측과 그 대책에 관한 연구)

  • 이봉용
    • 전기의세계
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    • v.29 no.1
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    • pp.65-72
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    • 1980
  • Arstrong-Whitehead theory on effective shielding and shielding failure is extended so that it is applicable to vertical line configuration the existing approaches on back-flash rate calculation are summerized and compared in particular on Model Line, and the usefulness of the whitehead approach is suggested.

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Electrical Characteristics Evaluation of Transmission Line Arresters (송전선로용 피뢰기의 전기적 특성 평가)

  • Kim, Seok-Sou;Heo, Jong-Cheol;Mun, In-Wook;Oh, Chang-Su
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1498-1499
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    • 2006
  • It has been reported that more than 50% of breakdown in transmission line for 154kV and above is due to lightning stroke. The flashover failure due to lightning stroke causes outage, voltage drop and instantaneous outage, Therefore line arrestors have been used in transmission line for protection from lightning stroke. In this paper, we describes electrical characteristics and performance test of line arrestor for transmission line.

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Seismic and collapse analysis of a UHV transmission tower-line system under cross-fault ground motions

  • Tian, Li;Bi, Wenzhe;Liu, Juncai;Dong, Xu;Xin, Aiqiang
    • Earthquakes and Structures
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    • v.19 no.6
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    • pp.445-457
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    • 2020
  • An ultra-high voltage (UHV) transmission system has the advantages of low circuitry loss, high bulk capacity and long-distance transmission capabilities over conventional transmission systems, but it is easier for this system to cross fault rupture zones and become damaged during earthquakes. This paper experimentally and numerically investigates the seismic responses and collapse failure of a UHV transmission tower-line system crossing a fault. A 1:25 reduced-scale model is constructed and tested by using shaking tables to evaluate the influence of the forward-directivity and fling-step effects on the responses of suspension-type towers. Furthermore, the collapse failure tests of the system under specific cross-fault scenarios are carried out. The corresponding finite element (FE) model is established in ABAQUS software and verified based on the Tian-Ma-Qu material model. The results reveal that the seismic responses of the transmission system under the cross-fault scenario are larger than those under the near-fault scenario, and the permanent ground displacements in the fling-step ground motions tend to magnify the seismic responses of the fault-crossing transmission system. The critical collapse peak ground acceleration (PGA), failure mode and weak position determined by the model experiment and numerical simulation are in relatively good agreement. The sequential failure of the members in Segments 4 and 5 leads to the collapse of the entire model, whereas other segments basically remain in the intact state.

The Stability Analysis of Submerged Excavated Slopes (수중 굴착사면의 안정해석)

  • Lee, M.W.;Lee, C.K.;Kim, H.J.;Ahn, K.K.;Heo, Y.
    • Journal of the Korean Society of Safety
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    • v.12 no.3
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    • pp.147-154
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    • 1997
  • The main purpose of this study is to investigate the failure surface in a soil mass by a excavation of the model ground. The failure mechanism of an earth structure is usually determined from field failure observations or from laboratory model tests at failure. To study the failure surface for the excavated slope, laboratory model tests were performed by changing the angle of the excavated slope and the ground condition. Results of the laboratory model tests were compared with those obtained with theoretical solutions using limit equilibrium analysis method. The results of model tests show that, there is a failure to create a straight line in the low angle of excavated surface and a create a circle as the angle increases. As the angle of excavated surface is increasing, the angle of the failure surface increases too. In the angle of the failure surface, the submerged ground is less than the dry ground at $3.2^{\circ}$.

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Ti/Al/Ti 전극의 Electro-Migration신뢰성 평가

  • Hyeon, Yeong-Hwan;Choe, Byeong-Deok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.339.2-339.2
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    • 2016
  • 본 연구에서는 Ti/Al/Ti 금속 배선의 Electro-Migration(EM) 현상을 분석했다. Van der Pauw, Greek Cross bridge, Straight line linear line bridge를 결합한 패턴을 제작하여, 온도 변화에 따른 EM의 발생 시간(Failure Time)을 측정했다. 측정 조건은 W/L=3.5/300 um 소자에 전류 밀도(current density)를 $J=10^4A/cm^2$로 고정하고, 온도를 300 K, 350 K, 400 K로 가변 시켰다. 측정된 Cumulative Failure의 50 % 되는 지점(Median Time To Failure; MTTF)은 각각 22.3시간, 18.46시간, 15.4시간으로 온도가 300 K에서 400 K로 증가함에 따라 MTTF가 6.9시간 감소했다. 이 결과를 통해 Black방정식에서 온도 변수가 $t_{50}$에 영향을 주는 것을 확인했다. 온도가 증가함에 따라 더 많은 전자들이 원자에 충돌하면서 운동량을 전달하고, 더 많은 원자들이 이주되면서 EM 발생 시간이 감소했다.

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A Particle Filtering Approach for On-Line Failure Prognosis in a Planetary Carrier Plate

  • Orchard, Marcos E.;Vachtsevanos, George J.
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.7 no.4
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    • pp.221-227
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    • 2007
  • This paper introduces an on-line particle-filtering-based framework for failure prognosis in nonlinear, non-Gaussian systems. This framework uses a nonlinear state-space model of the plant(with unknown time-varying parameters) and a particle filtering(PF) algorithm to estimate the probability density function(pdf) of the state in real-time. The state pdf estimate is then used to predict the evolution in time of the fault indicator, obtaining as a result the pdf of the remaining useful life(RUL) for the faulty subsystem. This approach provides information about the precision and accuracy of long-term predictions, RUL expectations, and 95% confidence intervals for the condition under study. Data from a seeded fault test for a UH-60 planetary carrier plate are used to validate the proposed methodology.

Establishment of Early Warning System of Steep Slope Failure Using Real-time Rainfall Data Analysis (실시간 강우자료분석을 활용한 산사태 경보시스템 연구)

  • Kim, Sung-Wook;Choi, Eun-Kyoung;Park, Dug-Keun;Park, Jung-Hoon;Son, Sung-Gon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.253-262
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    • 2010
  • In this study, localized heavy rainfall occurred during the collapse of steep slopes adjacent to the construction site and to ensure the safety of residents to build an early warning system was performed. Forecast/Alert range was estimated based on vulnerability landslide map and past disaster history. And established a critical line in consideration of the characteristics of local rainfall and operating a snake line, the study calculated causing and non-causing points. Also, be measured in real-time analysis of rainfall data in conjunction with the system before the steep slope failure occurred forecast/Alert System is presented.

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