• Title, Summary, Keyword: Fault

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Diagnosis of Poor Contact Fault in the Power Cable Using SSTDR (SSTDR을 이용한 케이블의 접촉 불량 고장 진단)

  • Kim, Taek-Hee;Jeon, Jeong-Chay
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.8
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    • pp.1442-1449
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    • 2016
  • This paper proposes a diagnosis to detecting poor contact fault and fault location. Electrical fire by poor contact fault of power cable occupied a large proportion in the total electrical installations. The proposed method has an object to prevent electrical fault in advance. But detecting poor contact fault is difficult to detect fault type and fault location by using conventional reflectometry due to faults generated intermittently and repeatedly on the time change. Therefore, in this paper poor contact fault and fault conditions were defined. System generating poor contact fault produced for the experimental setup. SSTDR and algorithm of reference signal elimination heighten performance detecting poor contact fault on live power cable. The diagnosis methods of signal process and analysis of reflected signal was proposed for detecting poor contact fault and fault location. The poor contact fault and location had been detected through proposed diagnosis methods. The fault location and error rate of detection were verified detecting accuracy by experiment results.

Tertiary basin in Korean peninsula and the study of geologic structure at Pohang basin (한반도의 제3기 분지와 포항분지내 지질구조 연구)

  • Lee, Byung-Joo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.3-17
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    • 2002
  • Tertiary Pohang basin distributed in south weatern part of the korean peninsula, is composed of Chunbuk formation as the basal conglomerate, Hakjon formation, Duho formation and intrusive basalt which is 15 Ma by absolute age data. The basement of the basin is represented by Cretaceous sedimentary rocks, Hakjon welded tuff and Chilpo welded tuff and rhyolite. The fault systems at the basement of the Pohang basin are consist of NNE direction fault, WNW to EW trend fault. NNE fault is not only strike-slip fault but also normal fault. n fault has sinistral strike-slip sene and the EW fault is strike-slip and normal fault. In the Tertiary basin, the fault system is represented by nm strike-slip fault, EW normal fault and NNE thrust fault. By these fault relationships and geometries, it is interpreted that NNE sinistral strike-slip fault and nomal fault have acted at Creceous times. At Tertiary tines, NNE dextralstrike-slip fault and EW normal fault has created. Progressively Tertiary Pohang basin was influenced by the trenspression to make thrust fault and fold, namely as inversion tectonics.

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A Fault Detection and Diagnosis in a PWR Steam Generator (PWM 증기발생기의 고장검출 및 진단에 관한 연구)

  • Park, Seung-Yub
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.1
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    • pp.120-127
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    • 1991
  • The purpose of this study is to develop a fault detection and diagnosis scheme that can monitor process fault and instrument fault of a steam generator. The suggested scheme consists of a Kalman filter and two bias estimators. Method of detecting process and instrument fault in a steam generator uses the mean test on the residual sequence of Kalman filter, designed for the unfailed system, to make a fault decision. Once a fault is detected, two bias estimators are driven to estimate the fault and to discriminate process fault and instrument fault. In case of process fault, the fault diagnosis of outlet temperature, feed-water heater and main steam control value is considered. In instrument fault, the fault diagnosis of steam genrator's three instruments is considered. Computer simulation tests show that on-line prompt fault detection and diagnosis can be performed very successfully.

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Fault diagnosis based on likelihood decomposition

  • Uosaki, Katsuji;Kagawa, Tetsuo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.272-275
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    • 1992
  • A novel fault diagnosis method based on likelihood decomposition is proposed for linear stochastic systems described by autoregressive (AR) model. Assuming that at some time instant .tau. the fault of one of the following two types is occurs: innovation fault (actuator fault); and observation fault (sensor fault), the log-likelihood function is decomposed into two components based on the observations before and after .tau., respectively, Then, the type of the fault is determined by comparing the log-likelihoods corresponding two types of faults. Numerical examples demonstrate the usefulness of the proposed diagnosis method.

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Design and Implementation of Fault Recorder for Transmission Line Protection (송전선로 보호용 고장기록장치의 설계 및 구현)

  • Choi, Soon-Choul;Park, Chul-Won
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.3
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    • pp.46-52
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    • 2016
  • When a fault occurs on a transmission line, it is important to identify the fault location as speedily as possible for improvement of the power supply reliability. Generally, distance to fault location is estimated by off line from the recorded data. Conventional fault recorder uses the fault data at one end. This paper deals with the design of an advanced fault recorder for enhancement accuracy of the fault distance estimation and fast detection a fault occurrence position. The major emphasis of the paper will be on the description of the hardware and software of the fault recorder. The fault locator algorithm utilizes a GPS time-synchronized the fault data at both ends. The fault data is transmitted to the other side substation through communication. The advanced fault locator includes a Power module, MPU(Main Processing Unit) module, ADPU(Analog Digital Processing Unit) module, and SIU(Signal Interface Unit) modules. The MMI firmware and software of an advanced fault recording device was implemented.

Fault Detection Technique in Railway High Voltage Distribution Lines using Wavelet Transform (웨이브렛 변환을 이용한 철도 고압배전선로의 고장검출기법)

  • Jung Ho-Sung;Han Moon-Seob;Lee Chang-Mu;Kim Joorak;Lee Han-Min
    • Proceedings of the KSR Conference
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    • pp.1274-1279
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    • 2004
  • This paper proposes technique to detect ground fault in railway high voltage distribution lines. Overcurrent relay technique is widely used for detecting one line ground fault that occurs most frequently in railway high voltage distribution lines. However, ground fault in distribution line is usually high impedance fault with arc. Because the fault current magnitude measured in substation is very small, the conventional overcurrent relay can't detect the high impedance ground fault. Therefore this paper proposes the advanced technique using wavelet transform. It extracts D1 component from fault signals and detects fault comparing magnitude of D1 component in each phase. To evaluate this proposed technique, we model distribution system using PSCAD/EMTDC and extract various fault data. In conclusion this technique can detect ground fault including high impedance fault regardless of fault distance, fault impedance etc.

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A fault detection and recovery mechanism for the fault-tolerance of a Mini-MAP system (Mini-MAP 시스템의 결함 허용성을 위한 결함 감지 및 복구 기법)

  • Mun, Hong-Ju;Kwon, Wook-Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.2
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    • pp.264-272
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    • 1998
  • This paper proposes a fault detection and recovery mechanism for a fault-tolerant Mini-MAP system, and provides detailed techniques for its implementation. This paper considers the fault-tolerant Mini-MAP system which has dual layer structure from the LLC sublayer down to the physical layer to cope with the faults of those layers. For a good fault detection, a redundant and hierarchical fault supervision architecture is proposed and its implementation technique for a stable detection operation is provided. Information for the fault location is provided from data reported with a fault detection and obtained by an additional network diagnosis. The faults are recovered by the stand-by sparing method applied for a dual network composed of two equivalent networks. A network switch mechanism is proposed to achieve a reliable and stable network function. A fault-tolerant Mini-MAP system is implemented by applying the proposed fault detection and recovery mechanism.

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The Real-Time Distance Relay Algorithm Using fault Location Estimation Information for Parallel Transmission Line (병행 2회선 송전선로에서 고장점 위치 추정정보를 이용한 실시간 거리계전 알고리즘)

  • 이재규;유석구
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.3
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    • pp.183-192
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    • 2003
  • This paper presents the real-time implemented distance relay algorithm which the fault distance is estimated with only local terminal information. When a single-phase-to-earth fault on a two-parallel transmission line occurs, the reach accuracy of distance relay is considerably affected by the unknown variables which are fault resistance, fault current at the fault point and zero- sequence current of sound line The zero-sequence current of sound line is estimated by using the zero sequence voltage which is measured by relaying location Also. the fault resistance is removed at the Process of numerical formula expansion. Lastly, the fault current through a fault point is expressed as a function of the zero-sequence current of fault line, zero-sequence current of sound line, and line, and fault distance. Therefore, the fault phase voltage can be expressed as the quadratic equation of the fault distance. The solution of this Quadratic equation is obtained by using a coefficient of the modified quadratic equation instead of using the square root solution method. After tile accurate fault distance is estimated. the mote accurate impedance is measured by using such an information.

Operational Method of Superconducting Fault Current Limiter with Reduction Function of Asymmetric Fault Current (비대칭 고장전류 저감 기능을 갖는 초전도 한류기 동작 방안)

  • Kim, Chang-Hwan;Seo, Hun-Chul;Kim, Kyu-Ho;Kim, Chul-Hwan;Rhee, Sang-Bong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.10
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    • pp.56-62
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    • 2014
  • When fault currents contain decaying DC offset, the peak value of the fault current in the first cycle of the fault period is higher than the fault current during the steady-state period. To reduce the asymmetric fault current, this paper proposes an operation scheme using the series connection of two hybrid type Superconducting Fault Current Limiters (SFCLs) : an auxiliary SFCL and a main SFCL. The proposed method calculates the fault angle by comparing the zero-crossing time with fault detection time. According to the fault angle calculated, an auxiliary SFCL operates to reduce an asymmetric fault current during half a cycle after fault occurrence. After this process, the fault current is limited by a main SFCL. To confirm the usefulness of the proposed method, case studies using Electro-Magnetic Transients Program (EMTP)/Alternative Transient Program (ATP) Draw are perfomed.

Integrated Fault Diagnosis Algorithm for Driving Motor of In-wheel Independent Drive Electric Vehicle (인휠 독립 구동 전기 자동차의 구동 모터 통합 고장 진단 알고리즘)

  • Jeon, Namju;Lee, Hyeongcheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.99-111
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    • 2016
  • This paper presents an integrated fault diagnosis algorithm for driving motor of In-wheel independent drive electric vehicle. Especially, this paper proposes a method that integrated the high level fault diagnosis and the low level fault diagnosis in order to improve a robustness and performance of the fault diagnosis system. The high level fault diagnosis is performed using the vehicle dynamics analysis and the low level fault diagnosis is carried using the motor system analysis. The validity of the high level fault diagnosis algorithms was verified through $Carsim^{(R)}$ and MATLAB/$Simulink^{(R)}$ cosimulation and the low level fault diagnosis's validity was shown by applying it to a MATLAB/$Simulink^{(R)}$ interior permanent magnet synchronous motor control system. Finally, this paper presents a fault diagnosis strategy by combining the high level fault diagnosis and the low level fault diagnosis.