• Title/Summary/Keyword: Fault signal

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Safety Diagnosis of Electric Train Driving System Using Vibration Signal (진동신호를 이용한 전기동차 구동장치의 안전성 평가)

  • 이봉현;최연선
    • Journal of KSNVE
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    • v.8 no.5
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    • pp.929-935
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    • 1998
  • Safety diagnosis of electric train driving system is performed using vibration signals of running electric train. Safety diagnosis is tried on the viewpoints of the appreciation of superannuation and the fault diagnosis of motor, reduction gear and bogie. The appreciation of superannuation is checked by the vibration levels of driving parts and the fault diagnosis is done by analyzing the frequencies of the vibration signals which are measured directly from a running electric train. The results shows that the vibration levels of each parts increase as the train gets older and each parts have their own frequency patterns of the vibration. Vibration propagation path is also investigated using calculated the coherence value between bogie and driving system. As the results, it is known that vibration signal can be utilized successfully for the safety diagnosis of the driving part of electric train.

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Developement of On-Line System for Vibration Signal Analysis (진동신호 분석을 위한 On-Line 시스템 개발)

  • Kim, O.S.;Rim, S.J.;Kim, Y.S.;Lee, Y.G.;Kim, J.C.;Chung, C.S.;Chung, S.J.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.616-619
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    • 1995
  • This paper describes developement of on-line system for vibration signal analysis. In the power system, the main reason of transformer fault is due to a large amount of current by a short-circuit and a ground-fault. The electromagnetic force caused by fault-current deforms transformer windings and results in vibration pattern change. Therefore if the continuous on-line vibration monitoring on transformer is performed, an incipient failure can be detected. The developed system is composed of data acquisition devices, user interface program, signal processing program, diagnosis and trend analysis program, self diagnosis program and communication program.

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A High-Frequency Signal Test Method for Embedded CMOS Op-amps

  • Kim Kang Chul;Han Seok Bung
    • Journal of information and communication convergence engineering
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    • v.3 no.1
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    • pp.28-32
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    • 2005
  • In this paper, we propose a novel test method to effectively detect hard and soft faults in CMOS 2-stage op-amps. The proposed method uses a very high frequency sinusoidal signal that exceeds unit gain bandwidth to maximize the fault effects. Since the proposed test method doesn't require any complex algorithms to generate the test pattern and uses only a single test pattern to detect all target faults, therefore test costs can be much reduced. The area overhead is also very small because the CUT is converted to a unit gain amplifier. Using HSPICE simulation, the results indicated a high degree of fault coverage for hard and soft faults in CMOS 2-stage op-amps. To verify this proposed method, we fabricated a CMOS op-amp that contained various short and open faults through the Hyundai 0.65-um 2-poly 2-metal CMOS process. Experimental results for the fabricated chip have shown that the proposed test method can effectively detect hard and soft faults in CMOS op-amps.

Fault Detection and Location using SWT on Underground Power Cable System (SWT를 이용한 지중송전계통의 고장검출 및 고장점 추정)

  • Jung, Chae-Kyun;Lee, Jong-Beom
    • Proceedings of the KIEE Conference
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    • 2004.11b
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    • pp.51-53
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    • 2004
  • In this paper, we are going to propose the new algorithms to detect, classify, discriminate the transient and the reflected signal from noise and thus discriminate the fault section and locale the fault accurately on underground power cable system. Actually, at this system, it's very difficult to discriminate the transient because of the reflected signal including many noises. Therefore, how to solve the noise interference is a big problem. In this paper, authors present a solution based on multiple scales correlation of the transient using stationary wavelet transform. It's simple, quick and straightforward. For applying all algorithms, we just use the signal captured in single end.

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Detection and Isolation Method for Operator Failure by Unknown Input Observer

  • Kim, Hwan-Seong;Kim, Seung-Min
    • Journal of Navigation and Port Research
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    • v.32 no.2
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    • pp.133-140
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    • 2008
  • In this paper, a fault detection method for operator failures using the observation technique is proposed. The suggested algorithm is extended using the conventional sensor/actuator fault detection method. First, it is assumed that operator failure affects human work operations, as it is an external input signal. With this assumption, a human work model with operator failure is suggested. Second, an unknown input observer with proportional and integral gains is introduced. The characteristic of this observer of estimating an external signal without an exact input is shown, and the conditions for the detection of an operator failure are proposed. Finally, by simulating the container crane operations, it is verified that the observer can accurately detect an operator failure and estimate its magnitude from the given internal signal.

A Study on Digital Fault Locator for Transmission Line (송전선로용 디지털 고장점 표정장치에 관한 연구)

  • Lee, Kyung-Min;Park, Chul-Won
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.4
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    • pp.291-296
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    • 2015
  • Transmission line is exposed to a large area, and then faults are likely to occur than the other component of power system. When a fault occurs on a transmission line, fault locator helps fast recovery of power supply on power system. This paper deals with the design of a digital fault locator for improvement accuracy of the fault distance estimation and a fault occurrence position for transmission line. The algorithm of a fault locator uses a DC offset removal filter and DFT filter. The algorithm utilizes a fault data of GPS time synchronized. The computed fault information is transmitted to the other side substation through communication. The digital fault locator includes MPU module, ADPU module, SIU module, and a power module. The MMI firmware and software of the fault locator was implemented.

Feature Vector Decision Method of Various Fault Signals for Neural-network-based Fault Diagnosis System (신경회로망 기반 고장 진단 시스템을 위한 고장 신호별 특징 벡터 결정 방법)

  • Han, Hyung-Seob;Cho, Sang-Jin;Chong, Ui-Pil
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.11
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    • pp.1009-1017
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    • 2010
  • As rotating machines play an important role in industrial applications such as aeronautical, naval and automotive industries, many researchers have developed various condition monitoring system and fault diagnosis system by applying various techniques such as signal processing and pattern recognition. Recently, fault diagnosis systems using artificial neural network have been proposed. For effective fault diagnosis, this paper used MLP(multi-layer perceptron) network which is widely used in pattern classification. Since using obtained signals without preprocessing as inputs of neural network can decrease performance of fault classification, it is very important to extract significant features of captured signals and to apply suitable features into diagnosis system according to the kinds of obtained signals. Therefore, this paper proposes the decision method of the proper feature vectors about each fault signal for neural-network-based fault diagnosis system. We applied LPC coefficients, maximum magnitudes of each spectral section in FFT and RMS(root mean square) and variance of wavelet coefficients as feature vectors and selected appropriate feature vectors as comparing error ratios of fault diagnosis for sound, vibration and current fault signals. From experiment results, LPC coefficients and maximum magnitudes of each spectral section showed 100 % diagnosis ratios for each fault and the method using wavelet coefficients had noise-robust characteristic.

Development of fault diagnosis fuzzy expert system for advanced control system (고급 분산 제어 시스템을 위한 고장 진단 퍼지 전문가 시스템의 개발)

  • 변승현;박세화;허윤기;서창준;이재혁;김병국;박동조;변증남
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.959-964
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    • 1993
  • We developed fault diagnosis fuzzy expert system for ACS(Advanced Control System). ACS is a DCS(Distributed Control System) with advanced control algorithm fault tolerance capabilities, fault diagnosis functions, and so on. Fuzzy expert system developed for an ACS in this paper gives an operator alarm signal depending on the state of process value and manipulated value, and the cause of alarm in real time. Simple experiment result with several rules for the-fault-diagnosis of drum level loop in Seoul-Power-Plant.

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Computer-Aided Vibration Signal Processing and Fault Monitoring System of Electrical-Fan Motors (컴퓨터를 이용한 선풍기모터의 진동신호처리 및 이상진단에 관한 연구)

  • Sin, Jung-Ho;Hwang, Gi-Hyeon;Choe, Yeong-Hyu;Park, Ju-Hyeok
    • 한국기계연구소 소보
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    • s.17
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    • pp.61-68
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    • 1987
  • The main objective of this paper is to develop the computer-aided vibrational signal processing and monitoring system of rotating machinery. This system has an automatic data acquisition capability and analyze for machine fault diagnosis. By spectrum analysis, machine’s failure can be identified. The monitoring system enables diagnosis of the fault in rotating machinery. In this study, the conventional electrical fans are selected as a model case. The date processing and fault monitoring system proposed here can be applied to the automation of the inspection process in assembling motor-shaft systems. The automatic inspection can enhance the product quality and keep it stable. Since the proposed system is developed for personal computers, it might be cheap in cost and easy in installation.

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A Method for Fault detecting on Power Transmission Network by use of M-sequence Correlation

  • Nishiyama, Eiji;Kuwanami, Kenshi;Owaki, Kosuke
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2570-2575
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    • 2003
  • Monitoring a power transmission line is significant for power electric companies. In this paper, we propose a new method for detecting an fault point of power transmission line by use of M-sequence correlation technique. In this method, detecting signal is used as one or plural M-sequences ( same characteristic polynomial, including normal and reverse mark, synchronized ). In receiving point, we make same sequence with the input one and take crosscorrelation function between M-sequence and the received signal. We can see transfer fanctions of plural paths between inputs and a output taps separated from different of delay times on the crosscorrelation function, and from these transfer fanctions, so we compare them when fault occurred with in usual.

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