• 제목/요약/키워드: Internal fault

검색결과 248건 처리시간 0.033초

개방형 CNC를 가지는 공작기계의 고장진단과 웹 서비스 기술 (Web Service Application for Machine Tool Fault with Open Architecture CNC)

  • 김동훈;김선호;윤원수;고광식
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.121-124
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    • 2003
  • The conventional CNC(Computerized Numerical Controller) of machine tool, which is dependent to CNC maker, was a closed architecture type. Therefore, it is impossible to implement a special user-define function to CNC. But recently, CNC is changed to OAC(Open Architecture Controller) type increasingly and the general function of CNC can be upgrade efficiently. This paper describes web service application for remote monitoring regarding the faults or machine tool with open architecture CNC. The major faults of CNC machine tool can be defined to the operational faults to be charged over 70%. Those faults are unpredictable because of being occurred without any warning. To generalize the fault diagnosis efficiently. two diagnosis models such as SF(Switching Function) and SSF(Step Switching Function) are proposed and the function of fault diagnosis is implemented to internal function of OAC. Also, to service remotely the faults of CNC machine tool. the suitable web environment is proposed and practical function is programmed to evaluate its operation on web.

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진행파 기법을 이용한 새로운 초고속 거리계전 방식 (A New Ultra High Speed Distance Relaying Method Using Travelling Wave Technique)

  • 강상희;박종근
    • 대한전기학회논문지
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    • 제40권12호
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    • pp.1203-1210
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    • 1991
  • This paper proposes a new distance relaying method based on fault initiated travelling waves for transmission line protection. The characteristics of this method are ultra high speed and excellent sensitivity. Travelling wave technique which is one of the distance relaying methods uses the discrete cross correlation function for discrimination between internal and external fault is remarkably reduced in case of a close up fault and an inception angle near or equal to zero fault. To cope with this problem, a new fast algorithm which uses backward wave summation method with fixed window is presented. The proposed method has been tested by numerical simulations using the EMTP.

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두 개의 자속경로를 갖는 직렬연결형 초전도한류기의 이중 피크전류제한 특성 (Double Peak Current Limiting Properties of Series Connection-Type SFCL with Two Magnetic Paths)

  • 고석철;한태희;임성훈
    • 조명전기설비학회논문지
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    • 제28권7호
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    • pp.62-68
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    • 2014
  • We proposed a series connection-type superconducting fault current limiter(SFCL) using E-I core that can prevent the internal magnetic flux generation of cores during normal operation, and prevent the saturation of cores due to a sudden magnetic flux generation at the initial stage of fault occurrence while limiting the peak current. Through a short-circuit simulation experiment, we analyzed the operating status of the two superconducting elements and limiting characteristics according to the size of the fault current peak before and after the failure. Further, the double peak current limiting characteristics according to the winding directions as well as the current and the voltage of each coil were compared and analyzed.

웨이브렛 변환기반 ACI 기법을 이용한 변압기 보호계전 알고리즘 (Protective Relaying Algorithm for Transformer Using ACI based on Wavelet Transform)

  • 이명윤;이종범
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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    • pp.293-296
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    • 2004
  • This paper proposes a new protective relaying algorithm using ACI(Advanced Computational Intelligence) and wavelet transform. To organize the advanced neuro-fuzzy algorithm, it is important to select target data reflecting various transformer transient states. These data are made of changing-rates of D1 coefficient and RSM value within half cycle after fault occurrence. Subsequently, the advanced neuro-fuzzy algorithm is obtained by converging the target data. As a result of applying the advanced neuro-fuzzy algorithm, discrimination between internal fault and inrush is correctly distinguished within half cycle after fault occurrence. Accordingly, it is evaluated that the proposed algorithm can effectively protect a transformer by correcting discrimination between winding fault and inrushing state.

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가상센서를 활용한 고장 허용 시스템에 관한 연구 (A Study on the Fault Tolerant System for the Optimum Performance of Virtual Sensor)

  • 송민우;최원석;이두완;장경식
    • 한국정보통신학회논문지
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    • 제14권7호
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    • pp.1634-1640
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    • 2010
  • 본 논문에서는 자동화설비에서 가장 많이 사용되는 근접센서와 실린더를 기준으로 두 가지 모델을 적용하여 "고장허용 시스템 구축"에 관한 연구를 진행하였다. Free Flow 컨베이어 상에서 센서의 고장발생 시 가상센서모드 (Virtual Sensor Mode)로 전환되어 정상동작 하는 것을 시뮬레이션을 통해 구현을 하였으며, 실린더의 내압(압력강하)을 이용하여 실린더의 동작 시 부하에 따른 아날로그 데이터변화를 확인함으로써 고장허용 시스템을 다양하게 적용할 수 있는 토대를 마련하였다. 이러한 방법은 실린더의 수명예상은 물론 Grease 주입예상시기와 실린더의 불량유무판단 등 개발자의 능력에 따라 여러 가지 응용이 가능할 것이라 생각된다.

대형 발전기 주보호를 위한 디지털 비율차동 계전기법 (Digital Ratio Differential Relaying for Main Protection of Large Generator)

  • 박철원;반우현
    • 전기학회논문지P
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    • 제61권1호
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    • pp.35-40
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    • 2012
  • An AC generator is an important component in producing an electric power and so it requires highly reliable protection relays to minimize the possibility of demage occurring under fault conditions. It is a need for research of digital generator protection system(DGPS) for the next-generation ECMS and an efficient operation of protection control system in power station. However, most of protection and control system used in power plants have been still imported as turn-key and operated in domestic. This may cause the lack of the correct understanding on the protection systems and methods, and thus have difficulties in optimal operation. In this paper, presented ratio differential relaying(RDR) is main protective element in generator protection IED. The fault detection technique, operation zone and setting value of the RDR were studied and, compared with two of the fault detection algorithm. For evaluation performance of the RDR, the data obtained from ATPDraw5.7p4 modeling was used. The proposed methods are shown to be able to rapidly identify internal fault and did not operate a miss-operation for all the external fault.

Dempster 결합룰에 의한 전력용 변압기 외란상태판정 (Disturbance State Identification of Power Transformer Based on Dempster's Rule of Combination)

  • 강상희;이승재;권태원;김상태;강용철;박종근
    • 대한전기학회논문지:전력기술부문A
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    • 제48권12호
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    • pp.1479-1485
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    • 1999
  • This paper proposes a fuzzy decision making method for power transformer protection to identify an internal fault from other transient states such as inrush, over-excitation and an external fault with current transformer (CT) saturation. In this paper, analyzing over 300 EMTP simulations of disturbances, four input variables are selected and fuzzified. At every sampling interval from half to one cycle after a disturbance, from the EMPT simulations, different fuzzy rule base is composed of twelve if-then fuzzy rules associated with their basic probability assignments for singleton- or compound-support hypotheses. Dempster's rule of combination is used to process the fuzzy rules and get the final decision. A series of test results clearly indicate that the method can identify not only an internal fault but also the other transients. The average of relay operation times is about 12(ms). The proposed method is implemented into a Digital Signal Processor (TMS320C31) and tested.

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조합논리회로의 다중결함검출 (Multiple Fault Detection in Combinational Logic Networks)

  • 고경식;김흥수
    • 대한전자공학회논문지
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    • 제12권4호
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    • pp.21-27
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    • 1975
  • 본 논문에서는 분기가 있는 일반조합논리회로의 다중결함을 검출할 수 있는 테스트집합을 구하는 절차를 유도하였다. 일반논리회로를 우선 내부분기점을 전후하여 이를 분기가 없는 부분회로로 분리하고 각 부분회로에 대한 최소테스트집합을 구한다. 다음에 각 부분테스트를 최대한으로 병립시켜 합성테스트를 구하여 종합적인 일차입력벡터를 정한다. 이러날 수 있는 모든 결함을 빠짐없이 피복할 수 있는 최소테스트집합을 구해가는 과정에 대해서는 각 를 들어 상세히 설명하였다. In this paper, a procedure for deriving of multiple fault detection test sets is presented for fan-out reconvergent combinational logic networks. A fan-out network is decomposed into a set of fan-out free subnetworks by breaking the internal fan-out points, and the minimal detecting test sets for each subnetwork are found separately. And then, the compatible tests amonng each test set are combined maximally into composite tests to generate primary input binary vectors. The technique for generating minimal test experiments which cover all the possible faults is illustrated in detail by examples.

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A new methodology for modeling explicit seismic common cause failures for seismic multi-unit probabilistic safety assessment

  • Jung, Woo Sik;Hwang, Kevin;Park, Seong Kyu
    • Nuclear Engineering and Technology
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    • 제52권10호
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    • pp.2238-2249
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    • 2020
  • In a seismic PSA, dependency among seismic failures of components has not been explicitly modeled in the fault tree or event tree. This dependency is separately identified and assigned with numbers that range from zero to unity that reflect the level of the mutual correlation among seismic failures. Because of complexity and difficulty in calculating combination probabilities of correlated seismic failures in complex seismic event tree and fault tree, there has been a great need of development to explicitly model seismic correlation in terms of seismic common cause failures (CCFs). If seismic correlations are converted into seismic CCFs, it is possible to calculate an accurate value of a top event probability or frequency of a complex seismic fault tree by using the same procedure as for internal, fire, and flooding PSA. This study first proposes a methodology to explicitly model seismic dependency by converting correlated seismic failures into seismic CCFs. As a result, this methodology will allow systems analysts to quantify seismic risk as what they have done with the CCF method in internal, fire, and flooding PSA.

편로드 유압실린더 내부 누유 검출을 위한 T—S 퍼지 모델 기반 샘플치 관측기 설계: LMI 접근법 (T—S Fuzzy Model-based Sampled-data Observer Design for Detecting Internal Oil Leakage in Single-rod Hydraulic Cylinder: LMI Approach)

  • 지성철;김효곤;박정우;이문직;강형주;이계홍
    • 한국해양공학회지
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    • 제30권5호
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    • pp.405-414
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    • 2016
  • This paper presents an internal oil leakage detection problem for a hydraulic single-rod cylinder. We derive the dynamics of the hydraulic cylinder as a state space model, and then design a T—S fuzzy model-based fault detection observer. We adopt an H observer design scheme so that the observer is robust against disturbance and relatively sensitive to the leakage fault. Sufficient design conditions are derived in the form of linear matrix inequalities. A numerical example is provided to verify the proposed techniques.