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Sample records for active fault detection

  1. Active fault detection in MIMO systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    The focus in this paper is on active fault detection (AFD) for MIMO systems with parametric faults. The problem of design of auxiliary inputs with respect to detection of parametric faults is investigated. An analysis of the design of auxiliary inputs is given based on analytic transfer functions...

  2. Controller modification applied for active fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob; Poulsen, Niels Kjølstad

    2014-01-01

    with the result that the detection and isolation time can be long. In this paper it will be shown, that this problem can be handled by using a modification of the feedback controller. By applying the YJBK-parameterization (after Youla, Jabr, Bongiorno and Kucera) for the controller, it is possible to modify...... the feedback controller with a minor effect on the external output in the fault free case. Further, in the faulty case, the signature of the auxiliary input can be optimized. This is obtained by using a band-pass filter for the YJBK parameter that is only effective in a small frequency range where...... the frequency for the auxiliary input is selected. This gives that it is possible to apply an auxiliary input with a reduced amplitude. An example is included to show the results....

  3. Stochastic Change Detection based on an Active Fault Diagnosis Approach

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2007-01-01

    The focus in this paper is on stochastic change detection applied in connection with active fault diagnosis (AFD). An auxiliary input signal is applied in AFD. This signal injection in the system will in general allow to obtain a fast change detection/isolation by considering the output or an error...

  4. Solar system fault detection

    Science.gov (United States)

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  5. Active-Varying Sampling-Based Fault Detection Filter Design for Networked Control Systems

    Directory of Open Access Journals (Sweden)

    Yu-Long Wang

    2014-01-01

    Full Text Available This paper is concerned with fault detection filter design for continuous-time networked control systems considering packet dropouts and network-induced delays. The active-varying sampling period method is introduced to establish a new discretized model for the considered networked control systems. The mutually exclusive distribution characteristic of packet dropouts and network-induced delays is made full use of to derive less conservative fault detection filter design criteria. Compared with the fault detection filter design adopting a constant sampling period, the proposed active-varying sampling-based fault detection filter design can improve the sensitivity of the residual signal to faults and shorten the needed time for fault detection. The simulation results illustrate the merits and effectiveness of the proposed fault detection filter design.

  6. Active Fault Detection and Isolation for Hybrid Systems

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Bak, Thomas

    2009-01-01

    An algorithm for active fault detection and isolation is proposed. In order to observe the failure hidden due to the normal operation of the controllers or the systems, an optimization problem based on minimization of test signal is used. The optimization based method imposes the normal and faulty...... models predicted outputs such that their discrepancies are observable by passive fault diagnosis technique. Isolation of different faults is done by implementation a bank of Extended Kalman Filter (EKF) where the convergence criterion for EKF is confirmed by Genetic Algorithm (GA). The method is applied...

  7. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  8. Network Power Fault Detection

    OpenAIRE

    Siviero, Claudio

    2013-01-01

    Network power fault detection. At least one first network device is instructed to temporarily disconnect from a power supply path of a network, and at least one characteristic of the power supply path of the network is measured at a second network device connected to the network while the at least one first network device is temporarily disconnected from the network

  9. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

    The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

  10. Fault Detection for Industrial Processes

    Directory of Open Access Journals (Sweden)

    Yingwei Zhang

    2012-01-01

    Full Text Available A new fault-relevant KPCA algorithm is proposed. Then the fault detection approach is proposed based on the fault-relevant KPCA algorithm. The proposed method further decomposes both the KPCA principal space and residual space into two subspaces. Compared with traditional statistical techniques, the fault subspace is separated based on the fault-relevant influence. This method can find fault-relevant principal directions and principal components of systematic subspace and residual subspace for process monitoring. The proposed monitoring approach is applied to Tennessee Eastman process and penicillin fermentation process. The simulation results show the effectiveness of the proposed method.

  11. Active fault diagnosis by temporary destabilization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    An active fault diagnosis method for parametric or multiplicative faults is proposed. The method periodically adds a term to the controller that for a short period of time renders the system unstable if a fault has occurred, which facilitates rapid fault detection. An illustrative example is given....

  12. Active Fault Diagnosis by Temporary Destabilization

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Henrik

    2006-01-01

    An active fault diagnosis method for parametric or multiplicative faults is proposed. The method periodically adds a term to the controller that for a short period of time renders the system unstable if a fault has occurred, which facilitates rapid fault detection. An illustrative example is given....

  13. Detecting Faults from Encoded Information

    NARCIS (Netherlands)

    Persis, Claudio De

    2003-01-01

    The problem of fault detection for linear continuous-time systems via encoded information is considered. The encoded information is received at a remote location by the monitoring deiice and assessed to infer the occurrence of the fault. A class of faults is considered which allows to use a simple

  14. Active fault detection and isolation of discrete-time linear time-varying systems: a set-membership approach

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba

    2013-01-01

    Active fault detection and isolation (AFDI) is used for detection and isolation of faults that are hidden in the normal operation because of a low excitation signal or due to the regulatory actions of the controller. In this paper, a new AFDI method based on set-membership approaches is proposed...... un-falsified, the AFDI method is used to generate an auxiliary signal that is injected into the system for detection and isolation of faults that remain otherwise hidden or non-isolated using passive FDI (PFDI) methods. Having the set-valued estimation of the states for each model, the proposed AFDI....... In set-membership approaches, instead of a point-wise estimation of the states, a set-valued estimation of them is computed. If this set becomes empty the given model of the system is not consistent with the measurements. Therefore, the model is falsified. When more than one model of the system remains...

  15. Final Technical Report: PV Fault Detection Tool.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  16. Rapprochement between Active Fault Diagnosis and Change Detection in ARMAX Systems

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2006-01-01

    The connection between AFD (Active Fault Diagnosis), ARMAX systems and RST controllers etc. are considered in this paper. It is shown that the applied setup in modern AFD for closed loop systems can be considered as a generalization of the setup used in connection with traditional methods...

  17. Static Decoupling in fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    1998-01-01

    An algebraic approach is given for a design of a static residual weighting factor in connection with fault detection. A complete parameterization is given of the weighting factor which will minimize a given performance index...

  18. Study of Active Faults in the Three Gorges Dam region by Detecting and Relocating Aftershocks

    Science.gov (United States)

    Huang, R.; Zhu, L.; Xu, Y.

    2014-12-01

    Seismicity in the Three Gorges Dam (TGD) region and its adjacent areas increased dramatically as the water- level of the TGD reservoir rises since its completion in 2003. Accordingly, many efforts have been put forward to quantify the seismicity and geological hazards in the region. However, the precise detective of earthquakes, especially for the minor ones, remains difficulty because of sparse distribution of permanent seismic stations. From December 2013 to June 2014, we deployed 30 three-component broadband seismic stations in the TGD region. During the deployment, we recorded two earthquakes of magnitudes lager than 5.0, one occurred on December 16th 2013 in Badong and another on March 30th 2014 in Zigui. We firstly used a sliding-window cross-correlation (SCC) detection technique to supplement the events catalog from the China Earthquake Networks Center. Over 500 new events with ML lager than 0.5 were detected. We then relocated 502 events out of the total 987 events using the double-difference (DD) relocation algorithm. We also determined moment tensors of some large earthquakes using gCAP. The results clearly show two active faults along Yangtze River with dips of 50 degrees and 90 degrees to a maximum depth of 10 km, respectively. And they also reveal that water might have permeated to a depth of 6 km corresponds to the interface of sediments and metamorphic basement beneath Zigui Basin. We thus preliminarily judge that the quakes are triggered by local stress adjustment resulting of fluctuation of Three Gorges reservoir's loading.

  19. Fault detection based on microseismic events

    Science.gov (United States)

    Yin, Chen

    2017-09-01

    In unconventional reservoirs, small faults allow the flow of oil and gas as well as act as obstacles to exploration; for, (1) fracturing facilitates fluid migration, (2) reservoir flooding, and (3) triggering of small earthquakes. These small faults are not generally detected because of the low seismic resolution. However, such small faults are very active and release sufficient energy to initiate a large number of microseismic events (MEs) during hydraulic fracturing. In this study, we identified microfractures (MF) from hydraulic fracturing and natural small faults based on microseismicity characteristics, such as the time-space distribution, source mechanism, magnitude, amplitude, and frequency. First, I identified the mechanism of small faults and MF by reservoir stress analysis and calibrated the ME based on the microseismic magnitude. The dynamic characteristics (frequency and amplitude) of MEs triggered by natural faults and MF were analyzed; moreover, the geometry and activity types of natural fault and MF were grouped according to the source mechanism. Finally, the differences among time-space distribution, magnitude, source mechanism, amplitude, and frequency were used to differentiate natural faults and manmade fractures.

  20. Wind turbine fault detection and fault tolerant control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Johnson, Kathryn

    2013-01-01

    In this updated edition of a previous wind turbine fault detection and fault tolerant control challenge, we present a more sophisticated wind turbine model and updated fault scenarios to enhance the realism of the challenge and therefore the value of the solutions. This paper describes...... the challenge model and the requirements for challenge participants. In addition, it motivates many of the faults by citing publications that give field data from wind turbine control tests....

  1. Fault Detection for Nonlinear Systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.H.

    1998-01-01

    The paper describes a general method for designing fault detection and isolation (FDI) systems for nonlinear processes. For a rich class of nonlinear systems, a nonlinear FDI system can be designed using convex optimization procedures. The proposed method is a natural extension of methods based...

  2. Fault detection using (PI) observers

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, J.; Shafai, B.

    The fault detection and isolation (FDI) problem in connection with Proportional Integral (PI) Observers is considered in this paper. A compact formulation of the FDI design problem using PI observers is given. An analysis of the FDI design problem is derived with respectt to the time domain...... properties. A method for design of PI observers applied to FDI is given....

  3. Structural Analysis Extended with Active Fault Isolation - Methods and Algorithms

    DEFF Research Database (Denmark)

    Gelso, Esteban R.; Blanke, Mogens

    2009-01-01

    Isolability of faults is a key issue in fault diagnosis whether the aim is maintenance or active fault-tolerant control. It is often encountered that while faults are detectable, they are only group-wise isolable from a usual diagnostic point of view. However, active injection of test signals...

  4. Actuator Fault Detection and Diagnosis for Quadrotors

    NARCIS (Netherlands)

    Lu, P.; Van Kampen, E.J.; Yu, B.

    2014-01-01

    This paper presents a method for fault detection and diagnosis of actuator loss of effectiveness for a quadrotor helicopter. This paper not only considers the detection of the actuator loss of effectiveness faults, but also addresses the diagnosis of the faults. The detection and estimation of the

  5. Exact, almost and delayed fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Saberi, Ali; Stoorvogel, Anton A.

    1999-01-01

    Considers the problem of fault detection and isolation while using zero or almost zero threshold. A number of different fault detection and isolation problems using exact or almost exact disturbance decoupling are formulated. Solvability conditions are given for the formulated design problems....... The l-step delayed fault detection problem is also considered for discrete-time systems....

  6. Fundamental problems in fault detection and identification

    DEFF Research Database (Denmark)

    Saberi, A.; Stoorvogel, A. A.; Sannuti, P.

    2000-01-01

    A number of different fundamental problems in fault detection and fault identification are formulated in this paper. The fundamental problems include exact, almost, generic and class-wise fault detection and identification. Necessary and sufficient conditions for the solvability of the fundamental...

  7. Fault detection and isolation for complex system

    Science.gov (United States)

    Jing, Chan Shi; Bayuaji, Luhur; Samad, R.; Mustafa, M.; Abdullah, N. R. H.; Zain, Z. M.; Pebrianti, Dwi

    2017-07-01

    Fault Detection and Isolation (FDI) is a method to monitor, identify, and pinpoint the type and location of system fault in a complex multiple input multiple output (MIMO) non-linear system. A two wheel robot is used as a complex system in this study. The aim of the research is to construct and design a Fault Detection and Isolation algorithm. The proposed method for the fault identification is using hybrid technique that combines Kalman filter and Artificial Neural Network (ANN). The Kalman filter is able to recognize the data from the sensors of the system and indicate the fault of the system in the sensor reading. Error prediction is based on the fault magnitude and the time occurrence of fault. Additionally, Artificial Neural Network (ANN) is another algorithm used to determine the type of fault and isolate the fault in the system.

  8. Central Asia Active Fault Database

    Science.gov (United States)

    Mohadjer, Solmaz; Ehlers, Todd A.; Kakar, Najibullah

    2014-05-01

    The ongoing collision of the Indian subcontinent with Asia controls active tectonics and seismicity in Central Asia. This motion is accommodated by faults that have historically caused devastating earthquakes and continue to pose serious threats to the population at risk. Despite international and regional efforts to assess seismic hazards in Central Asia, little attention has been given to development of a comprehensive database for active faults in the region. To address this issue and to better understand the distribution and level of seismic hazard in Central Asia, we are developing a publically available database for active faults of Central Asia (including but not limited to Afghanistan, Tajikistan, Kyrgyzstan, northern Pakistan and western China) using ArcGIS. The database is designed to allow users to store, map and query important fault parameters such as fault location, displacement history, rate of movement, and other data relevant to seismic hazard studies including fault trench locations, geochronology constraints, and seismic studies. Data sources integrated into the database include previously published maps and scientific investigations as well as strain rate measurements and historic and recent seismicity. In addition, high resolution Quickbird, Spot, and Aster imagery are used for selected features to locate and measure offset of landforms associated with Quaternary faulting. These features are individually digitized and linked to attribute tables that provide a description for each feature. Preliminary observations include inconsistent and sometimes inaccurate information for faults documented in different studies. For example, the Darvaz-Karakul fault which roughly defines the western margin of the Pamir, has been mapped with differences in location of up to 12 kilometers. The sense of motion for this fault ranges from unknown to thrust and strike-slip in three different studies despite documented left-lateral displacements of Holocene and late

  9. An arc fault detection system

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Kamal N.

    1997-12-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn, opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  10. Active fault diagnosis based on stochastic tests

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2008-01-01

    The focus of this paper is on stochastic change detection applied in connection with active fault diagnosis (AFD). An auxiliary input signal is applied in AFD. This signal injection in the system will in general allow us to obtain a fast change detection/isolation by considering the output...

  11. Fault Detection for a Diesel Engine Actuator

    DEFF Research Database (Denmark)

    Blanke, M.; Bøgh, S.A.; Jørgensen, R.B.

    1995-01-01

    An electro-mechanical position servo is introduced as a benchmark for mode-based Fault Detection and Identification (FDI).......An electro-mechanical position servo is introduced as a benchmark for mode-based Fault Detection and Identification (FDI)....

  12. Integration of control and fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, J.

    The integrated design of control and fault detection is studied. The result of the analysis is that it is possible to separate the design of the controller and the filter for fault detection in the case where the nominal model can be assumed to be fairly accurate. In the uncertain case, however...

  13. Aluminium Process Fault Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Nazatul Aini Abd Majid

    2015-01-01

    Full Text Available The challenges in developing a fault detection and diagnosis system for industrial applications are not inconsiderable, particularly complex materials processing operations such as aluminium smelting. However, the organizing into groups of the various fault detection and diagnostic systems of the aluminium smelting process can assist in the identification of the key elements of an effective monitoring system. This paper reviews aluminium process fault detection and diagnosis systems and proposes a taxonomy that includes four key elements: knowledge, techniques, usage frequency, and results presentation. Each element is explained together with examples of existing systems. A fault detection and diagnosis system developed based on the proposed taxonomy is demonstrated using aluminium smelting data. A potential new strategy for improving fault diagnosis is discussed based on the ability of the new technology, augmented reality, to augment operators’ view of an industrial plant, so that it permits a situation-oriented action in real working environments.

  14. Fault tolerant control based on active fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2005-01-01

    An active fault diagnosis (AFD) method will be considered in this paper in connection with a Fault Tolerant Control (FTC) architecture based on the YJBK parameterization of all stabilizing controllers. The architecture consists of a fault diagnosis (FD) part and a controller reconfiguration (CR) ...

  15. Active and passive faults detection by using the PageRank algorithm

    Science.gov (United States)

    Darooneh, Amir H.; Lotfi, Nastaran

    2014-08-01

    Here we try to find active and passive places for earthquakes in the geographical region of Iran. The approach of Abe and Suzuki is adopted for modeling the seismic history of Iran by a complex directed network. By using the PageRank algorithm, we assign to any places in the region an activity index. Then, we determine the most active and passive places.

  16. Fault Detection and Isolation for Spacecraft

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2002-01-01

    This article realizes nonlinear Fault Detection and Isolation for actuators, given there is no measurement of the states in the actuators. The Fault Detection and Isolation of the actuators is instead based on angular velocity measurement of the spacecraft and knowledge about the dynamics...... of the satellite. The algorithms presented in this paper are based on a geometric approach to achieve nonlinear Fault Detection and Isolation. The proposed algorithms are tested in a simulation study and the pros and cons of the algorithms are discussed....

  17. Detecting Fan Faults in refrigerated Cabinets

    DEFF Research Database (Denmark)

    Thybo, C.; Rasmussen, B.D.; Izadi-Zamanabadi, Roozbeh

    2002-01-01

    Fault detection in supermarket refrigeration systems is an important topic due to both economic and food safety reasons. If faults can be detected and diagnosed before the system drifts outside the specified operational envelope, service costs can be reduced and in extreme cases the costly...... faults in display cabinets under the wide operational conditions that display cabinets are exposed to. The approach described uses a non- linear parity equation comparing the heat transfer rates of the air and the refrigerant. The paper presents the detection method and discusses the application...

  18. Verification-based Software-fault Detection

    OpenAIRE

    Gladisch, Christoph David

    2011-01-01

    Software is used in many safety- and security-critical systems. Software development is, however, an error-prone task. In this dissertation new techniques for the detection of software faults (or software "bugs") are described which are based on a formal deductive verification technology. The described techniques take advantage of information obtained during verification and combine verification technology with deductive fault detection and test generation in a very unified way.

  19. Fault Detection and Isolation using Eigenstructure Assignment

    DEFF Research Database (Denmark)

    Jørgensen, R.B.; Patton, R.J.; Chen, J.

    1994-01-01

    The purpose of this article is to investigate the robustness to model uncertainties of observer based fault detection and isolation. The approach is designed with a straight forward dynamic nad the observer.......The purpose of this article is to investigate the robustness to model uncertainties of observer based fault detection and isolation. The approach is designed with a straight forward dynamic nad the observer....

  20. Statistical fault detection in photovoltaic systems

    KAUST Repository

    Garoudja, Elyes

    2017-05-08

    Faults in photovoltaic (PV) systems, which can result in energy loss, system shutdown or even serious safety breaches, are often difficult to avoid. Fault detection in such systems is imperative to improve their reliability, productivity, safety and efficiency. Here, an innovative model-based fault-detection approach for early detection of shading of PV modules and faults on the direct current (DC) side of PV systems is proposed. This approach combines the flexibility, and simplicity of a one-diode model with the extended capacity of an exponentially weighted moving average (EWMA) control chart to detect incipient changes in a PV system. The one-diode model, which is easily calibrated due to its limited calibration parameters, is used to predict the healthy PV array\\'s maximum power coordinates of current, voltage and power using measured temperatures and irradiances. Residuals, which capture the difference between the measurements and the predictions of the one-diode model, are generated and used as fault indicators. Then, the EWMA monitoring chart is applied on the uncorrelated residuals obtained from the one-diode model to detect and identify the type of fault. Actual data from the grid-connected PV system installed at the Renewable Energy Development Center, Algeria, are used to assess the performance of the proposed approach. Results show that the proposed approach successfully monitors the DC side of PV systems and detects temporary shading.

  1. Fault Detection for Quantized Networked Control Systems

    Directory of Open Access Journals (Sweden)

    Wei-Wei Che

    2013-01-01

    Full Text Available The fault detection problem in the finite frequency domain for networked control systems with signal quantization is considered. With the logarithmic quantizer consideration, a quantized fault detection observer is designed by employing a performance index which is used to increase the fault sensitivity in finite frequency domain. The quantized measurement signals are dealt with by utilizing the sector bound method, in which the quantization error is treated as sector-bounded uncertainty. By using the Kalman-Yakubovich-Popov (GKYP Lemma, an iterative LMI-based optimization algorithm is developed for designing the quantized fault detection observer. And a numerical example is given to illustrate the effectiveness of the proposed method.

  2. Data Fault Detection in Medical Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2015-03-01

    Full Text Available Medical body sensors can be implanted or attached to the human body to monitor the physiological parameters of patients all the time. Inaccurate data due to sensor faults or incorrect placement on the body will seriously influence clinicians’ diagnosis, therefore detecting sensor data faults has been widely researched in recent years. Most of the typical approaches to sensor fault detection in the medical area ignore the fact that the physiological indexes of patients aren’t changing synchronously at the same time, and fault values mixed with abnormal physiological data due to illness make it difficult to determine true faults. Based on these facts, we propose a Data Fault Detection mechanism in Medical sensor networks (DFD-M. Its mechanism includes: (1 use of a dynamic-local outlier factor (D-LOF algorithm to identify outlying sensed data vectors; (2 use of a linear regression model based on trapezoidal fuzzy numbers to predict which readings in the outlying data vector are suspected to be faulty; (3 the proposal of a novel judgment criterion of fault state according to the prediction values. The simulation results demonstrate the efficiency and superiority of DFD-M.

  3. Deformation Monitoring of AN Active Fault

    Science.gov (United States)

    Ostapchuk, A.

    2015-12-01

    The discovery of low frequency earthquakes, slow slip events and other deformation phenomena, new for geophysics, change our understanding of how the energy accumulated in the Earth's crust do release. The new geophysical data make one revise the underlying mechanism of geomechanical processes taking place in fault zones. Conditions for generating different slip modes are still unclear. The most vital question is whether a certain slip mode is intrinsic for a fault or may be controlled by external factors. This work presents the results of two and a half year deformation monitoring of a discontinuity in the zone of the Main Sayanskiy Fault. Main Sayanskiy Fault is right-lateral strike-slip fault. Observations were performed in the tunnel of Talaya seismic station (TLY), Irkutsk region, Russia. Measurements were carried out 70 m away from the entrance of the tunnel, the thickness of overlying rock was about 30 m. Inductive sensors of displacement were mounted at the both sides of a discontinuity, which recorded three components of relative fault side displacement with the accuracy of 0.2 mcm. Temperature variation inside the tunnel didn't exceed 0.5oC during the all period of observations. Important information about deformation properties of an active fault was obtained. A pronounced seasonality of deformation characteristics of discontinuity is observed in the investigated segment of rock. A great number of slow slip events with durations from several hours to several weeks were registered. Besides that alterations of fault deformation characteristics before the megathrust earthquake M9.0 Tohoku Oki 11 March 2011 and reaction to the event itself were detected. The work was supported by the Russian Science Foundation (grant no. 14-17-00719).

  4. Reset Tree-Based Optical Fault Detection

    Directory of Open Access Journals (Sweden)

    Howon Kim

    2013-05-01

    Full Text Available In this paper, we present a new reset tree-based scheme to protect cryptographic hardware against optical fault injection attacks. As one of the most powerful invasive attacks on cryptographic hardware, optical fault attacks cause semiconductors to misbehave by injecting high-energy light into a decapped integrated circuit. The contaminated result from the affected chip is then used to reveal secret information, such as a key, from the cryptographic hardware. Since the advent of such attacks, various countermeasures have been proposed. Although most of these countermeasures are strong, there is still the possibility of attack. In this paper, we present a novel optical fault detection scheme that utilizes the buffers on a circuit’s reset signal tree as a fault detection sensor. To evaluate our proposal, we model radiation-induced currents into circuit components and perform a SPICE simulation. The proposed scheme is expected to be used as a supplemental security tool.

  5. An Overview of Transmission Line Protection by Artificial Neural Network: Fault Detection, Fault Classification, Fault Location, and Fault Direction Discrimination

    Directory of Open Access Journals (Sweden)

    Anamika Yadav

    2014-01-01

    Full Text Available Contemporary power systems are associated with serious issues of faults on high voltage transmission lines. Instant isolation of fault is necessary to maintain the system stability. Protective relay utilizes current and voltage signals to detect, classify, and locate the fault in transmission line. A trip signal will be sent by the relay to a circuit breaker with the purpose of disconnecting the faulted line from the rest of the system in case of a disturbance for maintaining the stability of the remaining healthy system. This paper focuses on the studies of fault detection, fault classification, fault location, fault phase selection, and fault direction discrimination by using artificial neural networks approach. Artificial neural networks are valuable for power system applications as they can be trained with offline data. Efforts have been made in this study to incorporate and review approximately all important techniques and philosophies of transmission line protection reported in the literature till June 2014. This comprehensive and exhaustive survey will reduce the difficulty of new researchers to evaluate different ANN based techniques with a set of references of all concerned contributions.

  6. Aircraft Fault Detection and Classification Using Multi-Level Immune Learning Detection

    Science.gov (United States)

    Wong, Derek; Poll, Scott; KrishnaKumar, Kalmanje

    2005-01-01

    This work is an extension of a recently developed software tool called MILD (Multi-level Immune Learning Detection), which implements a negative selection algorithm for anomaly and fault detection that is inspired by the human immune system. The immunity-based approach can detect a broad spectrum of known and unforeseen faults. We extend MILD by applying a neural network classifier to identify the pattern of fault detectors that are activated during fault detection. Consequently, MILD now performs fault detection and identification of the system under investigation. This paper describes the application of MILD to detect and classify faults of a generic transport aircraft augmented with an intelligent flight controller. The intelligent control architecture is designed to accommodate faults without the need to explicitly identify them. Adding knowledge about the existence and type of a fault will improve the handling qualities of a degraded aircraft and impact tactical and strategic maneuvering decisions. In addition, providing fault information to the pilot is important for maintaining situational awareness so that he can avoid performing an action that might lead to unexpected behavior - e.g., an action that exceeds the remaining control authority of the damaged aircraft. We discuss the detection and classification results of simulated failures of the aircraft's control system and show that MILD is effective at determining the problem with low false alarm and misclassification rates.

  7. Fault Detection in Singular Bilinear Systems

    Directory of Open Access Journals (Sweden)

    Sara Mansouri Nasab

    2011-10-01

    Full Text Available Singular systems naturally exist in many physicall and practical systems in control issues. Also, a big group of nonlinear systems which can not be estimated by linear systems are carfully estimated by bilinear systems. On the other hand, if the user in sensetive systems dose not detect the fault on time,a considerable amount of facilities and information will be damaged and destroyed; therefore,the fault detection and recognition in singular bilinear systems with unknown input disturbances and faults by using bilinear sliding mode observer, is done in this paper because of the importance that singular bilinear systems have in modeling physical systems and undesirable effect of fault on performances of systems. For this perpose, have at first singular bilinear system is decomposed, then a sliding mode observer is considered for it. More over, a method is given for fault detection and isolation base on sliding mode observer. And at the end, we have a simulation for a numeral example to illustrate the effect of given method.

  8. PV Systems Reliability Final Technical Report: Ground Fault Detection

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  9. Fault Detection for Shipboard Monitoring and Decision Support Systems

    DEFF Research Database (Denmark)

    Lajic, Zoran; Nielsen, Ulrik Dam

    2009-01-01

    In this paper a basic idea of a fault-tolerant monitoring and decision support system will be explained. Fault detection is an important part of the fault-tolerant design for in-service monitoring and decision support systems for ships. In the paper, a virtual example of fault detection...... will be presented for a containership with a real decision support system onboard. All possible faults can be simulated and detected using residuals and the generalized likelihood ratio (GLR) algorithm....

  10. Generic, scalable and decentralized fault detection for robot swarms

    Science.gov (United States)

    Christensen, Anders Lyhne; Timmis, Jon

    2017-01-01

    Robot swarms are large-scale multirobot systems with decentralized control which means that each robot acts based only on local perception and on local coordination with neighboring robots. The decentralized approach to control confers number of potential benefits. In particular, inherent scalability and robustness are often highlighted as key distinguishing features of robot swarms compared with systems that rely on traditional approaches to multirobot coordination. It has, however, been shown that swarm robotics systems are not always fault tolerant. To realize the robustness potential of robot swarms, it is thus essential to give systems the capacity to actively detect and accommodate faults. In this paper, we present a generic fault-detection system for robot swarms. We show how robots with limited and imperfect sensing capabilities are able to observe and classify the behavior of one another. In order to achieve this, the underlying classifier is an immune system-inspired algorithm that learns to distinguish between normal behavior and abnormal behavior online. Through a series of experiments, we systematically assess the performance of our approach in a detailed simulation environment. In particular, we analyze our system’s capacity to correctly detect robots with faults, false positive rates, performance in a foraging task in which each robot exhibits a composite behavior, and performance under perturbations of the task environment. Results show that our generic fault-detection system is robust, that it is able to detect faults in a timely manner, and that it achieves a low false positive rate. The developed fault-detection system has the potential to enable long-term autonomy for robust multirobot systems, thus increasing the usefulness of robots for a diverse repertoire of upcoming applications in the area of distributed intelligent automation. PMID:28806756

  11. Generic, scalable and decentralized fault detection for robot swarms.

    Science.gov (United States)

    Tarapore, Danesh; Christensen, Anders Lyhne; Timmis, Jon

    2017-01-01

    Robot swarms are large-scale multirobot systems with decentralized control which means that each robot acts based only on local perception and on local coordination with neighboring robots. The decentralized approach to control confers number of potential benefits. In particular, inherent scalability and robustness are often highlighted as key distinguishing features of robot swarms compared with systems that rely on traditional approaches to multirobot coordination. It has, however, been shown that swarm robotics systems are not always fault tolerant. To realize the robustness potential of robot swarms, it is thus essential to give systems the capacity to actively detect and accommodate faults. In this paper, we present a generic fault-detection system for robot swarms. We show how robots with limited and imperfect sensing capabilities are able to observe and classify the behavior of one another. In order to achieve this, the underlying classifier is an immune system-inspired algorithm that learns to distinguish between normal behavior and abnormal behavior online. Through a series of experiments, we systematically assess the performance of our approach in a detailed simulation environment. In particular, we analyze our system's capacity to correctly detect robots with faults, false positive rates, performance in a foraging task in which each robot exhibits a composite behavior, and performance under perturbations of the task environment. Results show that our generic fault-detection system is robust, that it is able to detect faults in a timely manner, and that it achieves a low false positive rate. The developed fault-detection system has the potential to enable long-term autonomy for robust multirobot systems, thus increasing the usefulness of robots for a diverse repertoire of upcoming applications in the area of distributed intelligent automation.

  12. Active fault diagnosis by controller modification

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    2010-01-01

    Two active fault diagnosis methods for additive or parametric faults are proposed. Both methods are based on controller reconfiguration rather than on requiring an exogenous excitation signal, as it is otherwise common in active fault diagnosis. For the first method, it is assumed that the system...... in a way that guarantees the continuity of transition and global stability using a recent result on observer parameterization. An illustrative example inspired by a field study of a drag racing vehicle is given. For the second method, an active fault diagnosis method for parametric faults is proposed...... considered is controlled by an observer-based controller. The method is then based on a number of alternate observers, each designed to be sensitive to one or more additive faults. Periodically, the observer part of the controller is changed into the sequence of fault sensitive observers. This is done...

  13. Radial basis function neural network in fault detection of automotive ...

    African Journals Online (AJOL)

    Radial basis function neural network in fault detection of automotive engines. Adnan Hamad, Dingli Yu, JB Gomm, Mahavir S Sangha. Abstract. Fault detection and isolation have become one of the most important aspects of automobile design. A fault detection (FD) scheme is developed for automotive engines in this paper.

  14. Nonlinear Actuator Fault Detection and Isolation for a VTOL aircraft

    NARCIS (Netherlands)

    De Persis, Claudio; De Santis, Raffaella; Isidori, Alberto

    2001-01-01

    The recently introduced geometric approach to the nonlinear fault detection and isolation problem is used in this paper to detect actuator faults for the vertical takeoff and landing aircraft. The approach leads to a filter which, by processing the outputs of the plant, detects the faults and

  15. Model Based Fault Detection in a Centrifugal Pump Application

    DEFF Research Database (Denmark)

    Kallesøe, Carsten; Cocquempot, Vincent; Izadi-Zamanabadi, Roozbeh

    2006-01-01

    A model based approach for fault detection in a centrifugal pump, driven by an induction motor, is proposed in this paper. The fault detection algorithm is derived using a combination of structural analysis, observer design and Analytical Redundancy Relation (ARR) design. Structural considerations...... is capable of detecting four different faults in the mechanical and hydraulic parts of the pump....

  16. Internal Leakage Fault Detection and Tolerant Control of Single-Rod Hydraulic Actuators

    Directory of Open Access Journals (Sweden)

    Jianyong Yao

    2014-01-01

    Full Text Available The integration of internal leakage fault detection and tolerant control for single-rod hydraulic actuators is present in this paper. Fault detection is a potential technique to provide efficient condition monitoring and/or preventive maintenance, and fault tolerant control is a critical method to improve the safety and reliability of hydraulic servo systems. Based on quadratic Lyapunov functions, a performance-oriented fault detection method is proposed, which has a simple structure and is prone to implement in practice. The main feature is that, when a prescribed performance index is satisfied (even a slight fault has occurred, there is no fault alarmed; otherwise (i.e., a severe fault has occurred, the fault is detected and then a fault tolerant controller is activated. The proposed tolerant controller, which is based on the parameter adaptive methodology, is also prone to realize, and the learning mechanism is simple since only the internal leakage is considered in parameter adaptation and thus the persistent exciting (PE condition is easily satisfied. After the activation of the fault tolerant controller, the control performance is gradually recovered. Simulation results on a hydraulic servo system with both abrupt and incipient internal leakage fault demonstrate the effectiveness of the proposed fault detection and tolerant control method.

  17. Active fault traces along Bhuj Fault and Katrol Hill Fault, and ...

    Indian Academy of Sciences (India)

    observed on the left bank of a stream cutting the terrace. Faulting is well revealed by 10–30 cm thick gouge. Lack of any corroborating evidence show- ing displacement of Quaternary deposits makes it difficult to decipher the active nature of the fault. However, the probability cannot be ruled- out. In the outlet of the small ...

  18. Fault Detection, Isolation, and Accommodation for LTI Systems Based on GIMC Structure

    Directory of Open Access Journals (Sweden)

    D. U. Campos-Delgado

    2008-01-01

    Full Text Available In this contribution, an active fault-tolerant scheme that achieves fault detection, isolation, and accommodation is developed for LTI systems. Faults and perturbations are considered as additive signals that modify the state or output equations. The accommodation scheme is based on the generalized internal model control architecture recently proposed for fault-tolerant control. In order to improve the performance after a fault, the compensation is considered in two steps according with a fault detection and isolation algorithm. After a fault scenario is detected, a general fault compensator is activated. Finally, once the fault is isolated, a specific compensator is introduced. In this setup, multiple faults could be treated simultaneously since their effect is additive. Design strategies for a nominal condition and under model uncertainty are presented in the paper. In addition, performance indices are also introduced to evaluate the resulting fault-tolerant scheme for detection, isolation, and accommodation. Hard thresholds are suggested for detection and isolation purposes, meanwhile, adaptive ones are considered under model uncertainty to reduce the conservativeness. A complete simulation evaluation is carried out for a DC motor setup.

  19. Fault tolerant filtering and fault detection for quantum systems driven by fields in single photon states

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Qing, E-mail: qing.gao.chance@gmail.com; Dong, Daoyi, E-mail: daoyidong@gmail.com; Petersen, Ian R., E-mail: i.r.petersen@gmai.com [School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600 (Australia); Rabitz, Herschel, E-mail: hrabitz@princeton.edu [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-06-15

    The purpose of this paper is to solve the fault tolerant filtering and fault detection problem for a class of open quantum systems driven by a continuous-mode bosonic input field in single photon states when the systems are subject to stochastic faults. Optimal estimates of both the system observables and the fault process are simultaneously calculated and characterized by a set of coupled recursive quantum stochastic differential equations.

  20. FUZZY FAULT DETECTION FOR PERMANENT MAGNET SYNCHRONOUS GENERATOR

    Directory of Open Access Journals (Sweden)

    N. Selvaganesan

    2011-07-01

    Full Text Available Faults in engineering systems are difficult to avoid and may result in serious consequences. Effective fault detection and diagnosis can improve system reliability and avoid expensive maintenance. In this paper fuzzy system based fault detection scheme for permanent magnet synchronous generator is proposed. The sequence current components like positive and negative sequence currents are used as fault indicators and given as inputs to fuzzy fault detector. Also, the fuzzy inference system is created and rule base is evaluated, relating the sequence current component to the type of faults. These rules are fired for specific changes in sequence current component and the faults are detected. The feasibility of the proposed scheme for permanent magnet synchronous generator is demonstrated for different types of fault under various operating conditions using MATLAB/Simulink.

  1. A New Fault-tolerant Switched Reluctance Motor with reliable fault detection capability

    DEFF Research Database (Denmark)

    Lu, Kaiyuan

    2014-01-01

    Fault-Tolerant Switched Reluctance (FTSR) motor is proposed in this paper. A unique feature of this special design is that it allows use of the unexcited phase coils as search coils for fault detection. Therefore this new motor has all the advantages of using search coils for reliable fault detection......For reliable fault detection, often, search coils are used in many fault-tolerant drives. The search coils occupy extra slot space. They are normally open-circuited and are not used for torque production. This degrades the motor performance, increases the cost and manufacture complexity. A new...... while no extra search coil is actually needed. The motor itself is able to continue to work under any faulted conditions, providing fault-tolerant features. The working principle, performance evaluation of this motor will be demonstrated in this paper and Finite Element Analysis results are provided....

  2. Robust fault detection and isolation in stochastic systems

    Science.gov (United States)

    George, Jemin

    2012-07-01

    This article outlines the formulation of a robust fault detection and isolation (FDI) scheme that can precisely detect and isolate simultaneous actuator and sensor faults for uncertain linear stochastic systems. The given robust fault detection scheme based on the discontinuous robust observer approach would be able to distinguish between model uncertainties and actuator failures and therefore eliminate the problem of false alarms. Since the proposed approach involves estimating sensor faults, it can also be used for sensor fault identification and the reconstruction of true outputs from faulty sensor outputs. Simulation results presented here validate the effectiveness of the proposed robust FDI system.

  3. Fault Analysis and Detection in Microgrids with High PV Penetration

    Energy Technology Data Exchange (ETDEWEB)

    El Khatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez Alvidrez, Javier [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgrid modes of operation.

  4. Fault Detection and Isolation in Centrifugal Pumps

    DEFF Research Database (Denmark)

    Kallesøe, Carsten

    Centrifugal pumps are used in a variety of different applications, such as water supply, wastewater, and different industrial applications. Some pump installations are crucial for the applications to work. Failures can lead to substantial economic losses and can influence the life of many people...... is placed. The topic of this work is Fault Detection and Identification in centrifugal pumps. Different approaches are developed with special focus on robustness. Robustness with respect to disturbances, unknown parts of the system, and parameter variations are considered. All developed algorithms...... are tested on an industrial test setup, showing the usability of the algorithms on a real centrifugal pump....

  5. Frequency Based Fault Detection in Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    In order to obtain lower cost of energy for wind turbines fault detection and accommodation is important. Expensive condition monitoring systems are often used to monitor the condition of rotating and vibrating system parts. One example is the gearbox in a wind turbine. This system is operated...... gearbox. Only the generator speed measurement which is available in even simple wind turbine control systems is used as input. Consequently this proposed scheme does not need additional sensors and computers for monitoring the condition of the wind gearbox. The scheme is evaluated on a wide-spread wind...

  6. Fault Detection for Diesel Engine Actuator

    DEFF Research Database (Denmark)

    Blanke, M.; Bøgh, S.A.; Jørgensen, R.B.

    1994-01-01

    Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur.......Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur....

  7. A setup for active fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2006-01-01

    A setup for active fault diagnosis (AFD) of parametric faults in dynamic systems is formulated in this paper. It is shown that it is possible to use the same setup for both open loop systems, closed loop systems based on a nominal feedback controller as well as for closed loop systems based on a ...

  8. Experimental Fault Detection and Accomodation for an Agricultural Mobile Robot

    DEFF Research Database (Denmark)

    Østergaard, Kasper Zinck; Vinther, D.; Bisgaard, Morten

    2005-01-01

    This paper presents a systematic procedure to achieve fault tolerant capability for a four-wheel driven, four-wheel steered mobile robot moving in outdoor terrain. The procedure is exemplified through the paper by applying on a compass module. Detailed methods for fault detection and fault...

  9. Wavelet Packet based Detection of Surface Faults on Compact Discs

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Wickerhauser, Mladen Victor

    2006-01-01

    In this paper the detection of faults on the surface of a compact disc is addressed. Surface faults like scratches and fingerprints disturb the on-line measurement of the pick-up position relative to the track. This is critical since the pick-up is focused on and tracked at the information track...... based on these measurements. A precise detection of the surface fault is a prerequisite to a correct handling of the faults in order to protect the pick-up of the compact disc player from audible track losses. The actual fault handling which is addressed in other publications can be carried out...... by the use of dedicated filters adapted to remove the faults from the measurements. In this paper detection using wavelet packet filters is demonstrated. The filters are designed using the joint best basis method. Detection using these filters shows a distinct improvement compared to detection using ordinary...

  10. Planetary Gearbox Fault Detection Using Vibration Separation Techniques

    Science.gov (United States)

    Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    Studies were performed to demonstrate the capability to detect planetary gear and bearing faults in helicopter main-rotor transmissions. The work supported the Operations Support and Sustainment (OSST) program with the U.S. Army Aviation Applied Technology Directorate (AATD) and Bell Helicopter Textron. Vibration data from the OH-58C planetary system were collected on a healthy transmission as well as with various seeded-fault components. Planetary fault detection algorithms were used with the collected data to evaluate fault detection effectiveness. Planet gear tooth cracks and spalls were detectable using the vibration separation techniques. Sun gear tooth cracks were not discernibly detectable from the vibration separation process. Sun gear tooth spall defects were detectable. Ring gear tooth cracks were only clearly detectable by accelerometers located near the crack location or directly across from the crack. Enveloping provided an effective method for planet bearing inner- and outer-race spalling fault detection.

  11. Active fault diagnosis in closed-loop uncertain systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2006-01-01

    Fault diagnosis of parametric faults in closed-loop uncertain systems by using an auxiliary input vector is considered in this paper, i.e. active fault diagnosis (AFD). The active fault diagnosis is based directly on the socalled fault signature matrix, related to the YJBK (Youla, Jabr, Bongiorno...

  12. Illuminating Northern California’s Active Faults

    Science.gov (United States)

    Prentice, Carol S.; Crosby, Christopher J.; Whitehill, Caroline S.; Arrowsmith, J. Ramon; Furlong, Kevin P.; Philips, David A.

    2009-01-01

    Newly acquired light detection and ranging (lidar) topographic data provide a powerful community resource for the study of landforms associated with the plate boundary faults of northern California (Figure 1). In the spring of 2007, GeoEarthScope, a component of the EarthScope Facility construction project funded by the U.S. National Science Foundation, acquired approximately 2000 square kilometers of airborne lidar topographic data along major active fault zones of northern California. These data are now freely available in point cloud (x, y, z coordinate data for every laser return), digital elevation model (DEM), and KMZ (zipped Keyhole Markup Language, for use in Google EarthTM and other similar software) formats through the GEON OpenTopography Portal (http://www.OpenTopography.org/data). Importantly, vegetation can be digitally removed from lidar data, producing high-resolution images (0.5- or 1.0-meter DEMs) of the ground surface beneath forested regions that reveal landforms typically obscured by vegetation canopy (Figure 2)

  13. High impedance fault detection in low voltage networks

    Energy Technology Data Exchange (ETDEWEB)

    Christie, R.D. (Univ. of Washington, Seattle, WA (United States). Dept. of Electrical Engineering); Zadehgol, H.; Habib, M.M. (Seattle City Light, WA (United States))

    1993-10-01

    High impedance faults are those with fault current magnitude similar to load currents. Experimental results were obtained that conform operating experience that such faults can occur in the low voltage (600V and below) underground distribution networks typically found in urban power systems. These faults produce current waveforms qualitatively similar to those found on overhead feeders, but quantitatively smaller. Loose connectors can produce similar, but cleaner current characteristics. Noisy loads remain a major impediment to reliable detection. Design and installation of an inexpensive prototype fault detector on the Seattle City Light street network is described.

  14. Fault detection and isolation in motion monitoring system.

    Science.gov (United States)

    Kim, Duk-Jin; Suk, Myoung Hoon; Prabhakaran, B

    2012-01-01

    Pervasive computing becomes very active research field these days. A watch that can trace human movement to record motion boundary as well as to study of finding social life pattern by one's localized visiting area. Pervasive computing also helps patient monitoring. A daily monitoring system helps longitudinal study of patient monitoring such as Alzheimer's and Parkinson's or obesity monitoring. Due to the nature of monitoring sensor (on-body wireless sensor), however, signal noise or faulty sensors errors can be present at any time. Many research works have addressed these problems any with a large amount of sensor deployment. In this paper, we present the faulty sensor detection and isolation using only two on-body sensors. We have been investigating three different types of sensor errors: the SHORT error, the CONSTANT error, and the NOISY SENSOR error (see more details on section V). Our experimental results show that the success rate of isolating faulty signals are an average of over 91.5% on fault type 1, over 92% on fault type 2, and over 99% on fault type 3 with the fault prior of 30% sensor errors.

  15. Active fault research in India: achievements and future perspective

    Directory of Open Access Journals (Sweden)

    Mithila Verma

    2016-01-01

    Full Text Available This paper provides a brief overview of the progress made towards active fault research in India. An 8 m high scarp running for more than 80 km in the Rann of Kachchh is the classical example of the surface deformation caused by the great earthquake (1819 Kachchh earthquake. Integration of geological/geomorphic and seismological data has led to the identification of 67 active faults of regional scale, 15 in the Himalaya, 17 in the adjoining foredeep with as many as 30 neotectonic faults in the stable Peninsular India. Large-scale trenching programmes coupled with radiometric dates have begun to constraint the recurrence period of earthquakes; of the order of 500–1000 years for great earthquakes in the Himalaya and 10,000 years for earthquakes of >M6 in the Peninsular India. The global positioning system (GPS data in the stand alone manner have provided the fault parameters and length of rupture for the 2004 Andaman Sumatra earthquakes. Ground penetration radar (GPR and interferometric synthetic aperture radar (InSAR techniques have enabled detection of large numbers of new active faults and their geometries. Utilization of modern technologies form the central feature of the major programme launched by the Ministry of Earth Sciences, Government of India to prepare geographic information system (GIS based active fault maps for the country.

  16. An Improved Wavelet‐Based Multivariable Fault Detection Scheme

    KAUST Repository

    Harrou, Fouzi

    2017-07-06

    Data observed from environmental and engineering processes are usually noisy and correlated in time, which makes the fault detection more difficult as the presence of noise degrades fault detection quality. Multiscale representation of data using wavelets is a powerful feature extraction tool that is well suited to denoising and decorrelating time series data. In this chapter, we combine the advantages of multiscale partial least squares (MSPLSs) modeling with those of the univariate EWMA (exponentially weighted moving average) monitoring chart, which results in an improved fault detection system, especially for detecting small faults in highly correlated, multivariate data. Toward this end, we applied EWMA chart to the output residuals obtained from MSPLS model. It is shown through simulated distillation column data the significant improvement in fault detection can be obtained by using the proposed methods as compared to the use of the conventional partial least square (PLS)‐based Q and EWMA methods and MSPLS‐based Q method.

  17. Fault detection and fault-tolerant control for nonlinear systems

    CERN Document Server

    Li, Linlin

    2016-01-01

    Linlin Li addresses the analysis and design issues of observer-based FD and FTC for nonlinear systems. The author analyses the existence conditions for the nonlinear observer-based FD systems to gain a deeper insight into the construction of FD systems. Aided by the T-S fuzzy technique, she recommends different design schemes, among them the L_inf/L_2 type of FD systems. The derived FD and FTC approaches are verified by two benchmark processes. Contents Overview of FD and FTC Technology Configuration of Nonlinear Observer-Based FD Systems Design of L2 nonlinear Observer-Based FD Systems Design of Weighted Fuzzy Observer-Based FD Systems FTC Configurations for Nonlinear Systems< Application to Benchmark Processes Target Groups Researchers and students in the field of engineering with a focus on fault diagnosis and fault-tolerant control fields The Author Dr. Linlin Li completed her dissertation under the supervision of Prof. Steven X. Ding at the Faculty of Engineering, University of Duisburg-Essen, Germany...

  18. Active fault diagnosis in closed-loop systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2005-01-01

    Active fault diagnosis (AFD) of parametric faults is considered in connection with closed loop feedback systems. AFD involves auxiliary signals applied on the closed loop system. A fault signature matrix is introduced in connection with AFD and it is shown that if a limited number of faults can...... occur in the system, a fault separation in the fault signature matrix can be obtained. Then the single elements in the matrix only depend of a reduced number of parametric faults. This can directly be applied for fault isolation. If it is not possible to obtain this separation, it is shown how the fault...... signature matrix can be applied for a dynamical fault isolation, i.e. fault isolation based on the dynamic characteristic of the fault signature matrix as function of the different parametric faults....

  19. Fault detection and diagnosis of diesel engine valve trains

    Science.gov (United States)

    Flett, Justin; Bone, Gary M.

    2016-05-01

    This paper presents the development of a fault detection and diagnosis (FDD) system for use with a diesel internal combustion engine (ICE) valve train. A novel feature is generated for each of the valve closing and combustion impacts. Deformed valve spring faults and abnormal valve clearance faults were seeded on a diesel engine instrumented with one accelerometer. Five classification methods were implemented experimentally and compared. The FDD system using the Naïve-Bayes classification method produced the best overall performance, with a lowest detection accuracy (DA) of 99.95% and a lowest classification accuracy (CA) of 99.95% for the spring faults occurring on individual valves. The lowest DA and CA values for multiple faults occurring simultaneously were 99.95% and 92.45%, respectively. The DA and CA results demonstrate the accuracy of our FDD system for diesel ICE valve train fault scenarios not previously addressed in the literature.

  20. Subsurface structure identification of active fault based on magnetic anomaly data (Case study: Toru fault in Sumatera fault system)

    Science.gov (United States)

    Simanjuntak, Andrean V. H.; Husni, Muhammad; Syirojudin, Muhammad

    2017-07-01

    Toru segment, which is one of the active faults and located in the North of Sumatra, broke in 1984 ago on Pahae Jahe's earthquake with a magnitude 6.4 at the northern part of the fault which has a length of 23 km, and also broke again at the same place in 2008. The event of recurrence is very fast, which only 25 years old have repeatedly returned. However, in the elastic rebound theory, it probably happen with a fracture 50 cm and an average of the shear velocity 20 mm/year. The average focus of the earthquake sourced at a depth of 10 km and 23 km along its fracture zones, which can generate enough shaking 7 MMI and could breaking down buildings and create landslides on the cliff. Due to its seismic activity, this study was made to identify the effectiveness of this fault with geophysical methods. Geophysical methods such as gravity, geomagnetic and seismology are powerful tools for detecting subsurface structures of local, regional as well as of global scales. This study used to geophysical methods to discuss about total intensity of the geomagnetic anomaly data, resulted in the distribution of susceptibility values corresponding to the fault movement. The geomagnetic anomalies data was obtained from Geomag, such as total intensity measured by satellite. Data acquisition have been corrected for diurnal variations and reduced by IGRF. The study of earthquake records can be used for differentiating the active and non active fault elements. Modeling has been done using several methods, such as pseudo-gravity, reduce to pole, and upward or downward continuation, which is used to filter the geomagnetic anomaly data because the data has not fully representative of the fault structure. The results indicate that rock layers of 0 - 100 km depth encountered the process of intrusion and are dominated by sedimentary rocks that are paramagnetic, and that the ones of 100 - 150 km depth experienced the activity of subducting slab consisting of basalt and granite which are

  1. Fault diagnosis of active magnetic bearings based on Gaussian GLRT detector

    DEFF Research Database (Denmark)

    Nagel, Leon; Galeazzi, Roberto; Voigt, Andreas Jauernik

    2016-01-01

    to their inherent open loop instability. Occurrence of faults in one or more components of an active magnetic bearing may lead to loss of control of the rotor. Timely detection and isolation of faults in an active magnetic bearing could prevent hazardous system behaviour by enabling proper reconfiguration...... of the control system. A structural model of the bearing-rotor system is presented and used to perform a detectability and isolability analysis of faults in the magnetic actuator. Structural detectability and group-wise isolability is concluded for single and multiple faults in the actuators. A Gaussian...... generalized likelihood ratio test is proposed for detecting faults striking the electromagnet. The detector is capable of detecting and isolating the occurrence of faults in e.g. the windings of bearing by tracking changes in the mean value of a Gaussian distribution. The statistical distribution...

  2. An application of LTR design in fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    1998-01-01

    The fault detection and isolation (FDI) problem is considered in this paper. The FDI problem is formulated as a filter design problem, where the faults in the system is estimated and the disturbance acting on the system is rejected. It turns out that the filter design problem can be considered as...

  3. Arc Fault Detection & Localization by Electromagnetic-Acoustic Remote Sensing

    Science.gov (United States)

    Vasile, C.; Ioana, C.

    2017-05-01

    Electrical arc faults that occur in photovoltaic systems represent a danger due to their economic impact on production and distribution. In this paper we propose a complete system, with focus on the methodology, that enables the detection and localization of the arc fault, by the use of an electromagnetic-acoustic sensing system. By exploiting the multiple emissions of the arc fault, in conjunction with a real-time detection signal processing method, we ensure accurate detection and localization. In its final form, this present work will present in greater detail the complete system, the methods employed, results and performance, alongside further works that will be carried on.

  4. Open-circuit fault detection and tolerant operation for a parallel-connected SAB DC-DC converter

    DEFF Research Database (Denmark)

    Park, Kiwoo; Chen, Zhe

    2014-01-01

    This paper presents an open-circuit fault detection method and its tolerant control strategy for a Parallel-Connected Single Active Bridge (PCSAB) dc-dc converter. The structural and operational characteristics of the PCSAB converter lead to several advantages especially for high power applications...... also possesses better reliability under a certain open-circuit fault condition. The proposed fault diagnosis method identifies both location and type of a fault using one current sensor in the output. Depending on the type of the fault, the proposed fault-tolerant strategy tries to keep the capability...

  5. A summary of the active fault investigation in the extension sea area of Kikugawa fault and the Nishiyama fault , N-S direction fault in south west Japan

    Science.gov (United States)

    Abe, S.

    2010-12-01

    In this study, we carried out two sets of active fault investigation by the request from Ministry of Education, Culture, Sports, Science and Technology in the sea area of the extension of Kikugawa fault and the Nishiyama fault. We want to clarify the five following matters about both active faults based on those results. (1)Fault continuity of the land and the sea. (2) The length of the active fault. (3) The division of the segment. (4) Activity characteristics. In this investigation, we carried out a digital single channel seismic reflection survey in the whole area of both active faults. In addition, a high-resolution multichannel seismic reflection survey was carried out to recognize the detailed structure of a shallow stratum. Furthermore, the sampling with the vibrocoring to get information of the sedimentation age was carried out. The reflection profile of both active faults was extremely clear. The characteristics of the lateral fault such as flower structure, the dispersion of the active fault were recognized. In addition, from analysis of the age of the stratum, it was recognized that the thickness of the sediment was extremely thin in Holocene epoch on the continental shelf in this sea area. It was confirmed that the Kikugawa fault extended to the offing than the existing results of research by a result of this investigation. In addition, the width of the active fault seems to become wide toward the offing while dispersing. At present, we think that we can divide Kikugawa fault into some segments based on the distribution form of the segment. About the Nishiyama fault, reflection profiles to show the existence of the active fault was acquired in the sea between Ooshima and Kyushu. From this result and topographical existing results of research in Ooshima, it is thought that Nishiyama fault and the Ooshima offing active fault are a series of structure. As for Ooshima offing active fault, the upheaval side changes, and a direction changes too. Therefore, we

  6. Fault Detection of Wind Turbines with Uncertain Parameters

    DEFF Research Database (Denmark)

    Tabatabaeipour, Seyed Mojtaba; Odgaard, Peter Fogh; Bak, Thomas

    2012-01-01

    In this paper a set-membership approach for fault detection of a benchmark wind turbine is proposed. The benchmark represents relevant fault scenarios in the control system, including sensor, actuator and system faults. In addition we also consider parameter uncertainties and uncertainties...... on the torque coefficient. High noise on the wind speed measurement, nonlinearities in the aerodynamic torque and uncertainties on the parameters make fault detection a challenging problem. We use an effective wind speed estimator to reduce the noise on the wind speed measurements. A set-membership approach...... is used generate a set that contains all states consistent with the past measurements and the given model of the wind turbine including uncertainties and noise. This set represents all possible states the system can be in if not faulty. If the current measurement is not consistent with this set, a fault...

  7. Automatic Channel Fault Detection on a Small Animal APD-Based Digital PET Scanner

    Science.gov (United States)

    Charest, Jonathan; Beaudoin, Jean-François; Cadorette, Jules; Lecomte, Roger; Brunet, Charles-Antoine; Fontaine, Réjean

    2014-10-01

    Avalanche photodiode (APD) based positron emission tomography (PET) scanners show enhanced imaging capabilities in terms of spatial resolution and contrast due to the one to one coupling and size of individual crystal-APD detectors. However, to ensure the maximal performance, these PET scanners require proper calibration by qualified scanner operators, which can become a cumbersome task because of the huge number of channels they are made of. An intelligent system (IS) intends to alleviate this workload by enabling a diagnosis of the observational errors of the scanner. The IS can be broken down into four hierarchical blocks: parameter extraction, channel fault detection, prioritization and diagnosis. One of the main activities of the IS consists in analyzing available channel data such as: normalization coincidence counts and single count rates, crystal identification classification data, energy histograms, APD bias and noise thresholds to establish the channel health status that will be used to detect channel faults. This paper focuses on the first two blocks of the IS: parameter extraction and channel fault detection. The purpose of the parameter extraction block is to process available data on individual channels into parameters that are subsequently used by the fault detection block to generate the channel health status. To ensure extensibility, the channel fault detection block is divided into indicators representing different aspects of PET scanner performance: sensitivity, timing, crystal identification and energy. Some experiments on a 8 cm axial length LabPET scanner located at the Sherbrooke Molecular Imaging Center demonstrated an erroneous channel fault detection rate of 10% (with a 95% confidence interval (CI) of [9, 11]) which is considered tolerable. Globally, the IS achieves a channel fault detection efficiency of 96% (CI: [95, 97]), which proves that many faults can be detected automatically. Increased fault detection efficiency would be

  8. Fault detection of a benchmark wind turbine using interval analysis

    DEFF Research Database (Denmark)

    Tabatabaeipour, Seyed Mojtaba; Odgaard, Peter Fogh; Bak, Thomas

    2012-01-01

    of the measurement with a closed set that is computed based on the past measurements and a model of the system. If the measurement is not consistent with this set, a fault is detected. The result demonstrates effectiveness of the method for fault detection of the benchmark wind turbine.......This paper investigates a state estimation set- membership approach for fault detection of a benchmark wind turbine. The main challenges in the benchmark are high noise on the wind speed measurement and the nonlinearities in the aerodynamic torque such that the overall model of the turbine...... is nonlinear. We use an effective wind speed estimator to estimate the effective wind speed and then using interval analysis and monotonicity of the aerodynamic torque with respect to the effective wind speed, we can apply the method to the nonlinear system. The fault detection algorithm checks the consistency...

  9. Fault Management: Degradation Signature Detection, Modeling, and Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fault to Failure Progression (FFP) signature modeling and processing is a new method for applying condition-based signal data to detect degradation, to identify...

  10. Fault detection and isolation in processes involving induction machines

    Energy Technology Data Exchange (ETDEWEB)

    Zell, K.; Medvedev, A. [Control Engineering Group, Luleaa University of Technology, Luleaa (Sweden)

    1997-12-31

    A model-based technique for fault detection and isolation in electro-mechanical systems comprising induction machines is introduced. Two coupled state observers, one for the induction machine and another for the mechanical load, are used to detect and recognize fault-specific behaviors (fault signatures) from the real-time measurements of the rotor angular velocity and terminal voltages and currents. Practical applicability of the method is verified in full-scale experiments with a conveyor belt drive at SSAB, Luleaa Works. (orig.) 3 refs.

  11. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.

    2014-08-05

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  12. A fault detection service for wide area distributed computations.

    Energy Technology Data Exchange (ETDEWEB)

    Stelling, P.

    1998-06-09

    The potential for faults in distributed computing systems is a significant complicating factor for application developers. While a variety of techniques exist for detecting and correcting faults, the implementation of these techniques in a particular context can be difficult. Hence, we propose a fault detection service designed to be incorporated, in a modular fashion, into distributed computing systems, tools, or applications. This service uses well-known techniques based on unreliable fault detectors to detect and report component failure, while allowing the user to tradeoff timeliness of reporting against false positive rates. We describe the architecture of this service, report on experimental results that quantify its cost and accuracy, and describe its use in two applications, monitoring the status of system components of the GUSTO computational grid testbed and as part of the NetSolve network-enabled numerical solver.

  13. Fault detection of gearbox using time-frequency method

    Science.gov (United States)

    Widodo, A.; Satrijo, Dj.; Prahasto, T.; Haryanto, I.

    2017-04-01

    This research deals with fault detection and diagnosis of gearbox by using vibration signature. In this work, fault detection and diagnosis are approached by employing time-frequency method, and then the results are compared with cepstrum analysis. Experimental work has been conducted for data acquisition of vibration signal thru self-designed gearbox test rig. This test-rig is able to demonstrate normal and faulty gearbox i.e., wears and tooth breakage. Three accelerometers were used for vibration signal acquisition from gearbox, and optical tachometer was used for shaft rotation speed measurement. The results show that frequency domain analysis using fast-fourier transform was less sensitive to wears and tooth breakage condition. However, the method of short-time fourier transform was able to monitor the faults in gearbox. Wavelet Transform (WT) method also showed good performance in gearbox fault detection using vibration signal after employing time synchronous averaging (TSA).

  14. Development of Fault Models for Hybrid Fault Detection and Diagnostics Algorithm: October 1, 2014 -- May 5, 2015

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Howard; Braun, James E.

    2015-12-31

    This report describes models of building faults created for OpenStudio to support the ongoing development of fault detection and diagnostic (FDD) algorithms at the National Renewable Energy Laboratory. Building faults are operating abnormalities that degrade building performance, such as using more energy than normal operation, failing to maintain building temperatures according to the thermostat set points, etc. Models of building faults in OpenStudio can be used to estimate fault impacts on building performance and to develop and evaluate FDD algorithms. The aim of the project is to develop fault models of typical heating, ventilating and air conditioning (HVAC) equipment in the United States, and the fault models in this report are grouped as control faults, sensor faults, packaged and split air conditioner faults, water-cooled chiller faults, and other uncategorized faults. The control fault models simulate impacts of inappropriate thermostat control schemes such as an incorrect thermostat set point in unoccupied hours and manual changes of thermostat set point due to extreme outside temperature. Sensor fault models focus on the modeling of sensor biases including economizer relative humidity sensor bias, supply air temperature sensor bias, and water circuit temperature sensor bias. Packaged and split air conditioner fault models simulate refrigerant undercharging, condenser fouling, condenser fan motor efficiency degradation, non-condensable entrainment in refrigerant, and liquid line restriction. Other fault models that are uncategorized include duct fouling, excessive infiltration into the building, and blower and pump motor degradation.

  15. A Prognostic Method for Fault Detection in Wind Turbine Drivetrains

    DEFF Research Database (Denmark)

    Nejada, Amir R.; Odgaard, Peter Fogh; Gao, Zhen

    2014-01-01

    In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to the generator, using two additional angular velocity sensors on the intermedi......In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to the generator, using two additional angular velocity sensors...... on the intermediate shafts inside the gearbox. An angular velocity error function is defined and compared in the faulty and fault-free conditions in frequency domain. Faults can be detected from the change in the energy level of the frequency spectrum of an error function. The method is demonstrated by detecting...... bearing faults in three locations: the high-speed shaft stage, the planetary stage and the intermediate-speed shaft stage. Simulations of the faulty and fault-free cases are performed on a gearbox model implemented in multibody dynamic simulation software. The global loads on the gearbox are obtained from...

  16. Automatic fault detection for big solar heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, Frank; Vajen, Klaus; Krause, Michael [Univ. Kassel (Germany). Inst. fuer Thermische Energietechnik; Knoch, Andreas [Wagner und Co. Solartechnik, Coelbe (Germany)

    2008-07-01

    Solar heating systems require a permanent function control to ensure a proper operation. A new method with automatic fault detection for large solar heating systems has been developed. In a first and second step faults are identified by checking the reliability of individual measured values and via logical expressions of linked measured values. Since not all faults are identified by these simple procedures, in a third step measured energy gains are compared to simulated energy ones. The method has been tested and several failures have been identified. The method is characterized by a high level of automation and only few additional sensors are needed. (orig.)

  17. Fault Detection and Localization Method for Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe; Khan, Mohammad Rezwan

    2015-01-01

    The modular multilevel converter (MMC) is attractive for medium- or high-power applications because of the advantages of its high modularity, availability, and high power quality. However, reliability is one of the most important issues for MMCs those are made of large number of power electronic...... submodules (SMs). This paper proposed an effective fault detection and localization method for MMCs. An MMC fault can be detected by comparing the measured state variables and the estimated state variables with a Kalman Filter. The fault localization is based on the failure characteristics of the SM...... in the MMC. The proposed method can be implemented with less computational intensity and complexity, even in case that multiple SMs faults occur in a short time interval. The proposed method is not only implemented in simulations with professional tool PSCAD/EMTDC, but also verified with a down-scale MMC...

  18. Signal processing for solar array monitoring, fault detection, and optimization

    CERN Document Server

    Braun, Henry; Spanias, Andreas

    2012-01-01

    Although the solar energy industry has experienced rapid growth recently, high-level management of photovoltaic (PV) arrays has remained an open problem. As sensing and monitoring technology continues to improve, there is an opportunity to deploy sensors in PV arrays in order to improve their management. In this book, we examine the potential role of sensing and monitoring technology in a PV context, focusing on the areas of fault detection, topology optimization, and performance evaluation/data visualization. First, several types of commonly occurring PV array faults are considered and detection algorithms are described. Next, the potential for dynamic optimization of an array's topology is discussed, with a focus on mitigation of fault conditions and optimization of power output under non-fault conditions. Finally, monitoring system design considerations such as type and accuracy of measurements, sampling rate, and communication protocols are considered. It is our hope that the benefits of monitoring presen...

  19. Stator Fault Detection in Induction Motors by Autoregressive Modeling

    Directory of Open Access Journals (Sweden)

    Francisco M. Garcia-Guevara

    2016-01-01

    Full Text Available This study introduces a novel methodology for early detection of stator short circuit faults in induction motors by using autoregressive (AR model. The proposed algorithm is based on instantaneous space phasor (ISP module of stator currents, which are mapped to α-β stator-fixed reference frame; then, the module is obtained, and the coefficients of the AR model for such module are estimated and evaluated by order selection criterion, which is used as fault signature. For comparative purposes, a spectral analysis of the ISP module by Discrete Fourier Transform (DFT is performed; a comparison of both methodologies is obtained. To demonstrate the suitability of the proposed methodology for detecting and quantifying incipient short circuit stator faults, an induction motor was altered to induce different-degree fault scenarios during experimentation.

  20. Applying Parametric Fault Detection to a Mechanical System

    DEFF Research Database (Denmark)

    Felício, P.; Stoustrup, Jakob; Niemann, H.

    2002-01-01

    A way of doing parametric fault detection is described. It is based on the representation of parameter changes as linear fractional transformations (lfts). We describe a model with parametric uncertainty. Then a stabilizing controller is chosen and its robustness properties are studied via mu. Th....... The parameter changes (faults) are estimated based on estimates of the fictitious signals that enter the delta block in the lft. These signal estimators are designed by H-infinity techniques. The chosen example is an inverted pendulum....

  1. Fault-weighted quantification method of fault detection coverage through fault mode and effect analysis in digital I&C systems

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jaehyun; Lee, Seung Jun, E-mail: sjlee420@unist.ac.kr; Jung, Wondea

    2017-05-15

    Highlights: • We developed the fault-weighted quantification method of fault detection coverage. • The method has been applied to specific digital reactor protection system. • The unavailability of the module had 20-times difference with the traditional method. • Several experimental tests will be effectively prioritized using this method. - Abstract: The one of the most outstanding features of a digital I&C system is the use of a fault-tolerant technique. With an awareness regarding the importance of thequantification of fault detection coverage of fault-tolerant techniques, several researches related to the fault injection method were developed and employed to quantify a fault detection coverage. In the fault injection method, each injected fault has a different importance because the frequency of realization of every injected fault is different. However, there have been no previous studies addressing the importance and weighting factor of each injected fault. In this work, a new method for allocating the weighting to each injected fault using the failure mode and effect analysis data was proposed. For application, the fault-weighted quantification method has also been applied to specific digital reactor protection system to quantify the fault detection coverage. One of the major findings in an application was that we may estimate the unavailability of the specific module in digital I&C systems about 20-times smaller than real value when we use a traditional method. The other finding was that we can also classify the importance of the experimental case. Therefore, this method is expected to not only suggest an accurate quantification procedure of fault-detection coverage by weighting the injected faults, but to also contribute to an effective fault injection experiment by sorting the importance of the failure categories.

  2. FaultBuster: data driven fault detection and diagnosis for industrial systems

    DEFF Research Database (Denmark)

    Bergantino, Nicola; Caponetti, Fabio; Longhi, Sauro

    2009-01-01

    . Multivariate statistical models based on principal components are used to detect abnormal situations. Tailored to alarms, a probabilistic inference engine process the fault evidences to output the most probable diagnosis. Results from the DX 09 Diagnostic Challenge shown strong detection properties, while......Efficient and reliable monitoring systems are mandatory to assure the required security standards in industrial complexes. This paper describes the recent developments of FaultBuster, a purely data-driven diagnostic system. It is designed so to be easily scalable to different monitor tasks...

  3. Episodic activity of a dormant fault in tectonically stable Europe: The Rauw fault (NE Belgium)

    Science.gov (United States)

    Verbeeck, Koen; Wouters, Laurent; Vanneste, Kris; Camelbeeck, Thierry; Vandenberghe, Dimitri; Beerten, Koen; Rogiers, Bart; Schiltz, Marco; Burow, Christoph; Mees, Florias; De Grave, Johan; Vandenberghe, Noël

    2017-03-01

    Our knowledge about large earthquakes in stable continental regions comes from studies of faults that generated historical surface rupturing earthquakes or were identified by their recent imprint in the morphology. Here, we evaluate the co-seismic character and movement history of the Rauw fault in Belgium, which lacks geomorphological expression and historical/present seismicity. This 55-km-long normal fault, with known Neogene and possibly Early Pleistocene activity, is the largest offset fault west of the active Roer Valley Graben. Its trace was identified in the shallow subsurface based on high resolution geophysics. All the layers within the Late Pliocene Mol Formation (3.6 to 2.59 Ma) are displaced 7 m vertically, without growth faulting, but deeper deposits show increasing offset. A paleoseismic trench study revealed cryoturbated, but unfaulted, late glacial coversands overlying faulted layers of Mol Formation. In-between those deposits, the fault tip was eroded, along with evidence for individual displacement events. Fragmented clay gouge observed in a micromorphology sample of the main fault evidences co-seismic faulting, as opposed to fault creep. Based on optical and electron spin resonance dating and trench stratigraphy, the 7 m combined displacement is bracketed to have occurred between 2.59 Ma and 45 ka. The regional presence of the Sterksel Formation alluvial terrace deposits, limited to the hanging wall of the Rauw fault, indicates a deflection of the Meuse/Rhine confluence (1.0 to 0.5 Ma) by the fault's activity, suggesting that most of the offset occurred prior to/at this time interval. In the trench, Sterksel Formation is eroded but reworked gravel testifies for its former presence. Hence, the Rauw fault appears as typical of plate interior context, with an episodic seismic activity concentrated between 1.0 and 0.5 Ma or at least between 2.59 Ma to 45 ka, possibly related to activity variations in the adjacent, continuously active Roer Valley

  4. Electrical conductivity images of active and fossil fault zones

    OpenAIRE

    Oliver Ritter; A. Hoffmann-Rothe; P. A. Bedrosian; Ute Weckmann; V. Haak;  ;  

    2005-01-01

    We compare recent magnetotelluric investigations of four large fault systems: (i) the actively deforming, ocean-continent interplate San Andreas Fault (SAF), (ii) the actively deforming, continent-continent interplate Dead Sea Transform (DST), (iii) the currently inactive, trench-linked intraplate West Fault (WF) in northern Chile, and (iv) the Waterberg Fault/Omaruru Lineament (WF/OL) in Namibia, a fossilized intraplate shear zone formed during early Proterozoic continental collision. These ...

  5. Data driven fault detection and isolation: a wind turbine scenario

    Directory of Open Access Journals (Sweden)

    Rubén Francisco Manrique Piramanrique

    2015-04-01

    Full Text Available One of the greatest drawbacks in wind energy generation is the high maintenance cost associated to mechanical faults. This problem becomes more evident in utility scale wind turbines, where the increased size and nominal capacity comes with additional problems associated with structural vibrations and aeroelastic effects in the blades. Due to the increased operation capability, it is imperative to detect system degradation and faults in an efficient manner, maintaining system integrity, reliability and reducing operation costs. This paper presents a comprehensive comparison of four different Fault Detection and Isolation (FDI filters based on “Data Driven” (DD techniques. In order to enhance FDI performance, a multi-level strategy is used where:  the first level detects the occurrence of any given fault (detection, while  the second identifies the source of the fault (isolation. Four different DD classification techniques (namely Support Vector Machines, Artificial Neural Networks, K Nearest Neighbors and Gaussian Mixture Models were studied and compared for each of the proposed classification levels. The best strategy at each level could be selected to build the final data driven FDI system. The performance of the proposed scheme is evaluated on a benchmark model of a commercial wind turbine. 

  6. Robust filtering and fault detection of switched delay systems

    CERN Document Server

    Wang, Dong; Wang, Wei

    2013-01-01

    Switched delay systems appear in a wide field of applications including networked control systems, power systems, memristive systems. Though the large amount of ideas with respect to such systems have generated, until now, it still lacks a framework to focus on filter design and fault detection issues which are relevant to life safety and property loss. Beginning with the comprehensive coverage of the new developments in the analysis and control synthesis for switched delay systems, the monograph not only provides a systematic approach to designing the filter and detecting the fault of switched delay systems, but it also covers the model reduction issues. Specific topics covered include: (1) Arbitrary switching signal where delay-independent and delay-dependent conditions are presented by proposing a linearization technique. (2) Average dwell time where a weighted Lyapunov function is come up with dealing with filter design and fault detection issues beside taking model reduction problems. The monograph is in...

  7. Fault Detection and Isolation and Fault Tolerant Control of Wind Turbines Using Set-Valued Observers

    DEFF Research Database (Denmark)

    Casau, Pedro; Rosa, Paulo Andre Nobre; Tabatabaeipour, Seyed Mojtaba

    2012-01-01

    Research on wind turbine Operations & Maintenance (O&M) procedures is critical to the expansion of Wind Energy Conversion systems (WEC). In order to reduce O&M costs and increase the lifespan of the turbine, we study the application of Set-Valued Observers (SVO) to the problem of Fault Detection...

  8. Fault Detection and Isolation using Viability Theory and Interval Observers

    Science.gov (United States)

    Ghaniee Zarch, Majid; Puig, Vicenç; Poshtan, Javad

    2017-01-01

    This paper proposes the use of interval observers and viability theory in fault detection and isolation (FDI). Viability theory develops mathematical and algorithmic methods for investigating the adaptation to viability constraints of evolutions governed by complex systems under uncertainty. These methods can be used for checking the consistency between observed and predicted behavior by using simple sets that approximate the exact set of possible behavior (in the parameter or state space). In this paper, fault detection is based on checking for an inconsistency between the measured and predicted behaviors using viability theory concepts and sets. Finally, an example is provided in order to show the usefulness of the proposed approach.

  9. Detection of Interphase Fault Zone in Overhead Power Distribution Networks

    Directory of Open Access Journals (Sweden)

    E. Kalentionok

    2013-01-01

    Full Text Available Parametric methods have been recommended on the basis of current and voltage value recording in normal and emergency modes at a sub-transmission substation in order to detect two- and three-phase short circuits in overhead power distribution networks. The paper proposes to detect an inspection zone in order to locate an interphase fault with the help of analytical calculation of distance up to the fault point using 3–4 expressions on the basis of data obtained as a result of multiple metering pertaining to emergency mode parameters  with their subsequent statistical processing.

  10. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun

    2016-01-01

    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  11. Bayesian fault detection and isolation using Field Kalman Filter

    Science.gov (United States)

    Baranowski, Jerzy; Bania, Piotr; Prasad, Indrajeet; Cong, Tian

    2017-12-01

    Fault detection and isolation is crucial for the efficient operation and safety of any industrial process. There is a variety of methods from all areas of data analysis employed to solve this kind of task, such as Bayesian reasoning and Kalman filter. In this paper, the authors use a discrete Field Kalman Filter (FKF) to detect and recognize faulty conditions in a system. The proposed approach, devised for stochastic linear systems, allows for analysis of faults that can be expressed both as parameter and disturbance variations. This approach is formulated for the situations when the fault catalog is known, resulting in the algorithm allowing estimation of probability values. Additionally, a variant of algorithm with greater numerical robustness is presented, based on computation of logarithmic odds. Proposed algorithm operation is illustrated with numerical examples, and both its merits and limitations are critically discussed and compared with traditional EKF.

  12. Fuzzy model-based observers for fault detection in CSTR.

    Science.gov (United States)

    Ballesteros-Moncada, Hazael; Herrera-López, Enrique J; Anzurez-Marín, Juan

    2015-11-01

    Under the vast variety of fuzzy model-based observers reported in the literature, what would be the properone to be used for fault detection in a class of chemical reactor? In this study four fuzzy model-based observers for sensor fault detection of a Continuous Stirred Tank Reactor were designed and compared. The designs include (i) a Luenberger fuzzy observer, (ii) a Luenberger fuzzy observer with sliding modes, (iii) a Walcott-Zak fuzzy observer, and (iv) an Utkin fuzzy observer. A negative, an oscillating fault signal, and a bounded random noise signal with a maximum value of ±0.4 were used to evaluate and compare the performance of the fuzzy observers. The Utkin fuzzy observer showed the best performance under the tested conditions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Fault detection in reciprocating compressor valves under varying load conditions

    Science.gov (United States)

    Pichler, Kurt; Lughofer, Edwin; Pichler, Markus; Buchegger, Thomas; Klement, Erich Peter; Huschenbett, Matthias

    2016-03-01

    This paper presents a novel approach for detecting cracked or broken reciprocating compressor valves under varying load conditions. The main idea is that the time frequency representation of vibration measurement data will show typical patterns depending on the fault state. The problem is to detect these patterns reliably. For the detection task, we make a detour via the two dimensional autocorrelation. The autocorrelation emphasizes the patterns and reduces noise effects. This makes it easier to define appropriate features. After feature extraction, classification is done using logistic regression and support vector machines. The method's performance is validated by analyzing real world measurement data. The results will show a very high detection accuracy while keeping the false alarm rates at a very low level for different compressor loads, thus achieving a load-independent method. The proposed approach is, to our best knowledge, the first automated method for reciprocating compressor valve fault detection that can handle varying load conditions.

  14. Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA

    Science.gov (United States)

    Sherrod, Brian; Blakely, Richard J.; Lasher, John P.; Lamb, Andrew P.; Mahan, Shannon; Foit, Franklin F.; Barnett, Elizabeth

    2016-01-01

    The Wallula fault zone is an integral feature of the Olympic-Wallowa lineament, an ∼500-km-long topographic lineament oblique to the Cascadia plate boundary, extending from Vancouver Island, British Columbia, to Walla Walla, Washington. The structure and past earthquake activity of the Wallula fault zone are important because of nearby infrastructure, and also because the fault zone defines part of the Olympic-Wallowa lineament in south-central Washington and suggests that the Olympic-Wallowa lineament may have a structural origin. We used aeromagnetic and ground magnetic data to locate the trace of the Wallula fault zone in the subsurface and map a quarry exposure of the Wallula fault zone near Finley, Washington, to investigate past earthquakes along the fault. We mapped three main packages of rocks and unconsolidated sediments in an ∼10-m-high quarry exposure. Our mapping suggests at least three late Pleistocene earthquakes with surface rupture, and an episode of liquefaction in the Holocene along the Wallula fault zone. Faint striae on the master fault surface are subhorizontal and suggest reverse dextral oblique motion for these earthquakes, consistent with dextral offset on the Wallula fault zone inferred from offset aeromagnetic anomalies associated with ca. 8.5 Ma basalt dikes. Magnetic surveys show that the Wallula fault actually lies 350 m to the southwest of the trace shown on published maps, passes directly through deformed late Pleistocene or younger deposits exposed at Finley quarry, and extends uninterrupted over 120 km.

  15. Optimal input design for fault detection and diagnosis

    DEFF Research Database (Denmark)

    Sadegh, Payman; Madsen, Henrik; Holst, J.

    1995-01-01

    In the paper, the design of optimal input signals for detection and diagnosis in a stochastic dynamical system is investigated. The design is based on maximization of Kullback measure between the model under fault and the model under normal operation conditions. It is established that the optimal...

  16. Evaluation of Wind Farm Controller based Fault Detection and Isolation

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Shafiei, Seyed Ehsan

    2015-01-01

    detection and isolation and fault tolerant control has previously been proposed. Based on this model, and international competition on wind farm FDI was organized. The contributions were presented at the IFAC World Congress 2014. In this paper the top three contributions to this competition are shortly...... introduced and evaluated....

  17. Robust fault detection in open loop vs. closed loop

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, J.

    1997-01-01

    The robustness aspects of fault detection and isolation (FDI) for uncertain systems are considered. The FDI problem is considered in a standard problem formulation. The FDI design problem is analyzed both in the case where the control input signal is considered as a known external input signal (o...

  18. Fault detection for nonlinear systems - A standard problem approach

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1998-01-01

    The paper describes a general method for designing (nonlinear) fault detection and isolation (FDI) systems for nonlinear processes. For a rich class of nonlinear systems, a nonlinear FDI system can be designed using convex optimization procedures. The proposed method is a natural extension of met...

  19. Fault Detection Using the Zero Crossing Rate | Osuagwu | Nigerian ...

    African Journals Online (AJOL)

    A method of fault detection based on the zero crossing rate of the signal, Z1, and the zero crossing rate of the first order difference signal. Z2, is presented. It is shown that the parameter pair (Z1, Z2) possesses adequate discriminating potential to classify a signature as good or defective. The parameter pair also carries ...

  20. Airborne Gravity Measurements using a Helicopter with Special Emphases on Delineating Local Gravity Anomalies Mainly for Detecting Active Seismic Faults (Invited)

    Science.gov (United States)

    Segawa, J.

    2010-12-01

    The first aerial gravity measurement in Japan started in 1998 using a Japanese airborne gravimeter ‘ Segawa-TKeiki airborne gravimeter Model FGA-1’. We lay emphasis on the measurement of detailed gravity structures at the land-to-sea border areas and mountainous areas. This is the reason why we use a helicopter and make surveys at low altitude and low speed. We have so far made measurement at twelve sites and the total flight amounts to 20,000km. The accuracy of measurement is 1.5 mgal and half-wavelength resolution is 1.5 km. The Japanese type gravimeter consists of a servo-accelerometer type gravity sensor, a horizontal platform controlled by an optical fiber gyro, GPS positioning system, and a data processing system. Helicopter movement has to be precisely monitored three-dimensionally to calculate the vehicle’s acceleration noises. The necessary accuracy of positioning of the vehicle must be better than 10 cm in positioning error. Our helicopter gravity measurement has a special target in Japan to investigate active seismic faults located across land-to-sea borderlines. In Japan, it is generally thought that gravity over most of the country has already been measured by the governmental surveys, leaving the land-sea border lines and mountainous zones unsurveyed as difficult-to-access areas. In addition the use of airplane or helicopter in Japan appeared disadvantageous because of the narrowness of the Japanese Islands. Under such situations the author thought there still remained a particular as well as unique need for aerial gravity measurement in Japan, i.e. the need for detailed and seamless knowledge of gravity structures across land-to-sea border lines to elucidate complicated crustal structures of the Japanese Islands as well as distribution of active seismic faults for disaster prevention. The results of gravity measurements we have conducted so far include those of 12 sites. In the following the brief logs of our measurements are listed. 1)April

  1. Open Fault Detection and Tolerant Control for a Five Phase Inverter Driving System

    Directory of Open Access Journals (Sweden)

    Seung-Koo Baek

    2016-05-01

    Full Text Available This paper proposes a fault detection and the improved fault-tolerant control for an open fault in the five-phase inverter driving system. The five-phase induction machine has a merit of fault-tolerant control due to its increased number of phases. This paper analyzes an open fault pattern of one switch and proposes an effective fault detection method based upon this analysis. The proposed fault detection method using the analyzed patterns is applied in the power inverter. In addition, when the open fault occurs in the one switch of the induction machine driving system, the proposed fault-tolerant control method is used to operate the induction machine using the remaining healthy phases, after performing the fault detection method. Simulation and experiment results are provided to validate the proposed technique.

  2. Observer Based Fault Detection and Moisture Estimating in Coal Mill

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Mataji, Babak

    2008-01-01

     requirements to the general performance of power plants. Detection  of faults and moisture content estimation are consequently of high interest in the handling of the problems caused by faults and moisture content. The coal flow out of the mill is the obvious variable to monitor, when detecting non-intended drops in the coal......In this paper an observer-based method for detecting faults and estimating moisture content in the coal in coal mills is presented. Handling of faults and operation under special conditions, such as high moisture content in the coal, are of growing importance due to the increasing...... flow out of the coal mill. However, this variable is not measurable. Another estimated variable is the moisture content, which is only "measurable" during steady-state operations of the coal mill. Instead, this paper suggests a method where these unknown variables are estimated based on a simple energy...

  3. Active current control in wind power plants during grid faults

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Phillip C.; Rodriguez, Pedro

    2010-01-01

    Modern wind power plants are required and designed to ride through faults in electrical networks, subject to fault clearing. Wind turbine fault current contribution is required from most countries with a high amount of wind power penetration. In order to comply with such grid code requirements......, wind turbines usually have solutions that enable the turbines to control the generation of reactive power during faults. This paper addresses the importance of using an optimal injection of active current during faults in order to fulfil these grid codes. This is of relevant importance for severe...

  4. Development and Test of Methods for Fault Detection and Isolation

    DEFF Research Database (Denmark)

    Jørgensen, R.B.

    Almost all industrial systemns are automated to ensure optimal production both in relation to energy consumtion and safety to equipment and humans. All working parts are individually subject to faults. This can lead to unacceptable economic loss or injury to people. This thesis deals with a monit......Almost all industrial systemns are automated to ensure optimal production both in relation to energy consumtion and safety to equipment and humans. All working parts are individually subject to faults. This can lead to unacceptable economic loss or injury to people. This thesis deals...... they are especiallu crucial for the entire operaiton of a closed loop system. The purpose of the thesis is to investigate, deveop, and verify methods for fault detection and isolation on control loop systems. An Industrial Position Controller, (IPC), laboratory setup is used as an application example throughout...... the thesis. The IPC offers prospects of repeated fault scenarios, and support studies in robustness issues. The thesis contributes with a numerical fault analysis representation, practical applications of existing methods for FDI, and a method for robust FDI for practical applications....

  5. Battery Fault Detection with Saturating Transformers

    Science.gov (United States)

    Davies, Francis J. (Inventor); Graika, Jason R. (Inventor)

    2013-01-01

    A battery monitoring system utilizes a plurality of transformers interconnected with a battery having a plurality of battery cells. Windings of the transformers are driven with an excitation waveform whereupon signals are responsively detected, which indicate a health of the battery. In one embodiment, excitation windings and sense windings are separately provided for the plurality of transformers such that the excitation waveform is applied to the excitation windings and the signals are detected on the sense windings. In one embodiment, the number of sense windings and/or excitation windings is varied to permit location of underperforming battery cells utilizing a peak voltage detector.

  6. Statistical Feature Extraction for Fault Locations in Nonintrusive Fault Detection of Low Voltage Distribution Systems

    Directory of Open Access Journals (Sweden)

    Hsueh-Hsien Chang

    2017-04-01

    Full Text Available This paper proposes statistical feature extraction methods combined with artificial intelligence (AI approaches for fault locations in non-intrusive single-line-to-ground fault (SLGF detection of low voltage distribution systems. The input features of the AI algorithms are extracted using statistical moment transformation for reducing the dimensions of the power signature inputs measured by using non-intrusive fault monitoring (NIFM techniques. The data required to develop the network are generated by simulating SLGF using the Electromagnetic Transient Program (EMTP in a test system. To enhance the identification accuracy, these features after normalization are given to AI algorithms for presenting and evaluating in this paper. Different AI techniques are then utilized to compare which identification algorithms are suitable to diagnose the SLGF for various power signatures in a NIFM system. The simulation results show that the proposed method is effective and can identify the fault locations by using non-intrusive monitoring techniques for low voltage distribution systems.

  7. Extreme Hydrothermal Conditions Near an Active Geological Fault, DFDP-2B Borehole, Alpine Fault, New Zealand

    Science.gov (United States)

    Sutherland, R.; Townend, J.; Toy, V.; Allen, M.; Baratin, L. M.; Barth, N. C.; Beacroft, L.; Benson, A.; Boese, C. M.; Boles, A.; Boulton, C. J.; Capova, L.; Carpenter, B. M.; Celerier, B. P.; Chamberlain, C. J.; Conze, R.; Cooper, A.; Coussens, J.; Coutts, A.; Cox, S.; Craw, L.; Doan, M. L.; Eccles, J. D.; Faulkner, D.; Grieve, J.; Grochowski, J.; Gulley, A.; Henry, G.; Howarth, J. D.; Jacobs, K. M.; Jeppson, T.; Kato, N.; Keys, S.; Kirilova, M.; Kometani, Y.; Lukács, A.; Langridge, R.; Lin, W.; Little, T.; Mallyon, D.; Mariani, E.; Marx, R.; Massiot, C.; Mathewson, L.; Melosh, B.; Menzies, C. D.; Moore, J.; Morales, L. F. G.; Morgan, C.; Mori, H.; Niemeijer, A. R.; Nishikawa, O.; Nitsch, O.; Paris Cavailhes, J.; Pooley, B.; Prior, D. J.; Pyne, A.; Sauer, K. M.; Savage, M. K.; Schleicher, A.; Schmitt, D. R.; Shigematsu, N.; Taylor-Offord, S.; Tobin, H. J.; Upton, P.; Valdez, R. D.; Weaver, K.; Wiersberg, T.; Williams, J. N.; Yeo, S.; Zimmer, M.; Broderick, N.

    2015-12-01

    The DFDP-2B borehole sampled rocks above and within the upper part of the Alpine Fault, New Zealand, to a depth of 893 m in late 2014. The experiment was the first to drill a major geological fault zone that is active and late in its earthquake cycle. We determined ambient fluid pressures 8-10% above hydrostatic and a geothermal gradient of 130-150 °C/km in rocks above the fault. These unusual ambient conditions can be explained by a combination of: rock advection that transports heat from depth by uplift and oblique slip on the fault; and fluid advection through fractured rock, driven by topographic forcing, which concentrates heat and causes fluid over-pressure in the valley. Highly-anomalous ambient conditions can exist in the vicinity of active faults, and earthquake and mineralization processes occur within these zones.

  8. A Unified Nonlinear Adaptive Approach for Detection and Isolation of Engine Faults

    Science.gov (United States)

    Tang, Liang; DeCastro, Jonathan A.; Zhang, Xiaodong; Farfan-Ramos, Luis; Simon, Donald L.

    2010-01-01

    A challenging problem in aircraft engine health management (EHM) system development is to detect and isolate faults in system components (i.e., compressor, turbine), actuators, and sensors. Existing nonlinear EHM methods often deal with component faults, actuator faults, and sensor faults separately, which may potentially lead to incorrect diagnostic decisions and unnecessary maintenance. Therefore, it would be ideal to address sensor faults, actuator faults, and component faults under one unified framework. This paper presents a systematic and unified nonlinear adaptive framework for detecting and isolating sensor faults, actuator faults, and component faults for aircraft engines. The fault detection and isolation (FDI) architecture consists of a parallel bank of nonlinear adaptive estimators. Adaptive thresholds are appropriately designed such that, in the presence of a particular fault, all components of the residual generated by the adaptive estimator corresponding to the actual fault type remain below their thresholds. If the faults are sufficiently different, then at least one component of the residual generated by each remaining adaptive estimator should exceed its threshold. Therefore, based on the specific response of the residuals, sensor faults, actuator faults, and component faults can be isolated. The effectiveness of the approach was evaluated using the NASA C-MAPSS turbofan engine model, and simulation results are presented.

  9. Nonlinear observer based fault detection and isolation for a momentum wheel

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2001-01-01

    This article realizes nonlinear Fault Detection and Isolation for a momentum wheel. The Fault Detection and Isolation is based on a Failure Mode and Effect Analysis, which states which faults might occur and can be detected. The algorithms presented in this paper are based on a geometric approach...... toachieve nonlinear Fault Detection and Isolation. The proposed algorithms are tested in a simulation study and the pros and cons of the algorithm are discussed....

  10. PCB Fault Detection Using Image Processing

    Science.gov (United States)

    Nayak, Jithendra P. R.; Anitha, K.; Parameshachari, B. D., Dr.; Banu, Reshma, Dr.; Rashmi, P.

    2017-08-01

    The importance of the Printed Circuit Board inspection process has been magnified by requirements of the modern manufacturing environment where delivery of 100% defect free PCBs is the expectation. To meet such expectations, identifying various defects and their types becomes the first step. In this PCB inspection system the inspection algorithm mainly focuses on the defect detection using the natural images. Many practical issues like tilt of the images, bad light conditions, height at which images are taken etc. are to be considered to ensure good quality of the image which can then be used for defect detection. Printed circuit board (PCB) fabrication is a multidisciplinary process, and etching is the most critical part in the PCB manufacturing process. The main objective of Etching process is to remove the exposed unwanted copper other than the required circuit pattern. In order to minimize scrap caused by the wrongly etched PCB panel, inspection has to be done in early stage. However, all of the inspections are done after the etching process where any defective PCB found is no longer useful and is simply thrown away. Since etching process costs 0% of the entire PCB fabrication, it is uneconomical to simply discard the defective PCBs. In this paper a method to identify the defects in natural PCB images and associated practical issues are addressed using Software tools and some of the major types of single layer PCB defects are Pattern Cut, Pin hole, Pattern Short, Nick etc., Therefore the defects should be identified before the etching process so that the PCB would be reprocessed. In the present approach expected to improve the efficiency of the system in detecting the defects even in low quality images

  11. Model-based fault detection for proton exchange membrane fuel cell ...

    African Journals Online (AJOL)

    user

    In this paper, an intelligent model-based fault detection (FD) is developed for proton ... process behaviors, efficient and advanced automated diagnostic systems .... Finally, the nature and likely cause of the faults are analyzed by the relations ..... Her research interest includes artificial intelligence, fault tolerant control, fault ...

  12. Nonlinear observer based fault detection and isolation for a momentum wheel

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2001-01-01

    This article realizes nonlinear Fault Detection and Isolation for a momentum wheel. The Fault Detection and Isolation is based on a Failure Mode and Effect Analysis, which states which faults might occur and can be detected. The algorithms presented in this paper are based on a geometric approach...

  13. Faults

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Through the study of faults and their effects, much can be learned about the size and recurrence intervals of earthquakes. Faults also teach us about crustal...

  14. Fault Detection of Bearing Systems through EEMD and Optimization Algorithm

    OpenAIRE

    Dong-Han Lee; Jong-Hyo Ahn; Bong-Hwan Koh

    2017-01-01

    This study proposes a fault detection and diagnosis method for bearing systems using ensemble empirical mode decomposition (EEMD) based feature extraction, in conjunction with particle swarm optimization (PSO), principal component analysis (PCA), and Isomap. First, a mathematical model is assumed to generate vibration signals from damaged bearing components, such as the inner-race, outer-race, and rolling elements. The process of decomposing vibration signals into intrinsic mode functions (IM...

  15. Integration of Fault Detection and Isolation with Control Using Neuro-fuzzy Scheme

    Directory of Open Access Journals (Sweden)

    A. Asokan

    2009-10-01

    Full Text Available In this paper an algorithms is developed for fault diagnosis and fault tolerant control strategy for nonlinear systems subjected to an unknown time-varying fault. At first, the design of fault diagnosis scheme is performed using model based fault detection technique. The neuro-fuzzy chi-square scheme is applied for fault detection and isolation. The fault magnitude and time of occurrence of fault is obtained through neuro-fuzzy chi-square scheme. The estimated magnitude of the fault magnitude is normalized and used by the feed-forward control algorithm to make appropriate changes in the manipulated variable to keep the controlled variable near its set value. The feed-forward controller acts along with feed-back controller to control the multivariable system. The performance of the proposed scheme is applied to a three- tank process for various types of fault inputs to show the effectiveness of the proposed approach.

  16. Model based Fault Detection and Isolation for Driving Motors of a Ground Vehicle

    Directory of Open Access Journals (Sweden)

    Young-Joon Kim

    2016-04-01

    Full Text Available This paper proposes model based current sensor and position sensor fault detection and isolation algorithm for driving motor of In-wheel independent drive electric vehicle. From low level perspective, fault diagnosis conducted and analyzed to enhance robustness and stability. Composing state equation of interior permanent magnet synchronous motor (IPMSM, current sensor fault and position sensor fault diagnosed with parity equation. Validation and usefulness of algorithm confirmed based on IPMSM fault occurrence simulation data.

  17. Development of Fault Detection System using Wavelength Division Multiplexing Transmission of Optical Fiber Current Sensor

    Science.gov (United States)

    Kayaki, Masahiro; Hirata, Toshinari; Kurosawa, Kiyoshi; Kondo, Reishi; Yamada, Toshiharu; Itakura, Eiji

    A fault detection system is applied to power lines consisting of both overhead power line and underground power cable in order to detect a fault on the underground power cable section and prevent the automatic reclosing. The fault detection system using optical fiber current sensor has two subjects. The fist subject is that we have to use wound-type current transformer together, when applying the fault detection system to single-core underground power cable. The second subject is that we are not able to detect three-phase short-circuit fault in using the fault detection system. This paper describes that we developed a new fault detection system using optical fiber current sensor by applying the multiplex transmission technology of optical fiber current sensor signal in order to solve these subjects.

  18. Fault detection system for Argentine Research Reactor instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Polenta, H.P. (Argentine Navy, Comodoro Py 2055 Office 11-93, 1104 - Buenos Aires (Argentina)); Bernard, J.A. (Nuclear Reactor Laboratory, Massachusetts Institute of Technology, 138 Albany Street, Cambridge, Massachusetts 02139 (United States)); Ray, A. (205 Mechanical Engineering Department, Pennsylvania State University, University Park, Pennsylvania 16802 (United States))

    1993-01-20

    The design and implementation of a redundancy management scheme for the on-line detection and isolation of faulty sensors is presented. Such a device is potentially useful in reactor-powered spacecraft for enhancing the processing capabilities of the main computer. The fault detection device can be used as an integral part of intelligent instrumentation systems. The device has been built using an 8-bit microcontroller and commercially available electronic hardware. The software is completely portable. The operation of this device has been successfully demonstrated for real-time validation of sensor data on Argentina's RA-1 Research Reactor.

  19. Scalable and Fault Tolerant Failure Detection and Consensus

    Energy Technology Data Exchange (ETDEWEB)

    Katti, Amogh [University of Reading, UK; Di Fatta, Giuseppe [University of Reading, UK; Naughton III, Thomas J [ORNL; Engelmann, Christian [ORNL

    2015-01-01

    Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum's User Level Failure Mitigation proposal has introduced an operation, MPI_Comm_shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI_Comm_shrink operation requires a fault tolerant failure detection and consensus algorithm. This paper presents and compares two novel failure detection and consensus algorithms. The proposed algorithms are based on Gossip protocols and are inherently fault-tolerant and scalable. The proposed algorithms were implemented and tested using the Extreme-scale Simulator. The results show that in both algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus.

  20. Active faulting and folding along the Jumilla Fault Zone, northeastern Betics, Spain

    Science.gov (United States)

    Van Balen, R. T.; Forzoni, A.; Van Dam, J. A.

    2015-05-01

    The Jumilla Fault Zone (JFZ) is an ENE-WSW topographic lineament in the external part of the eastern Betic Cordillera. It represents an active fault. Three small basins are aligned along the JFZ, the La Celia-, Alqueria- and Jumilla basins. The tectonic geomorphology of the La Celia- and Alqueria basins consists of folds, a set of normal fault scarps, strike-slip lineaments, fault-springs, tectonically-modified drainage lines and elevated gypsum/anhydrite diapirs. Two of the scarps are normal faults generated by the extensional collapse of one of the folds. The other scarps are secondary normal faults generated by transtensional left-lateral motions along the JFZ. Normal fault scarps that developed on conglomerates are considerably steeper (~ 30°) than those affecting softer marly materials (post-Messinian deposits in the studied basins. The discrepancy between the age of the tectonic landforms and the late Neogene age of the basin infill can be explained by an endo- to exhorheic change in the drainage system, due to the capture of the ancient basin lake system by tributaries of the nearby Segura river. The cessation of sedimentation in the basins resulted in the preservation of tectonic landforms.

  1. Fault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia

    KAUST Repository

    Trippanera, D.

    2015-10-08

    Recent studies highlight the importance of annual-scale dike-induced rifting episodes in developing normal faults and graben along the active axis of magmatic divergent plate boundaries (MDPB). However, the longer-term (102-105 years) role of diking on the cumulative surface deformation and evolution of MDPB is not yet well understood. To better understand the longer-term normal faults and graben along the axis of MDPB, we analyze fissure swarms in Iceland and Ethiopia. We first focus on the simplest case of immature fissure swarms, with single dike-fed eruptive fissures; these consist of a <1 km wide graben bordered by normal faults with displacement up to a few meters, consistent with theoretical models and geodetic data. A similar structural pattern is found, with asymmetric and multiple graben, within wider mature fissure swarms, formed by several dike-fed eruptive fissures. We then consider the lateral termination of normal faults along these graben, to detect their upward or downward propagation. Most faults terminate as open fractures on flat surface, suggesting downward fault propagation; this is consistent with recent experiments showing dike-induced normal faults propagating downward from the surface. However, some normal faults also terminate as open fractures on monoclines, which resemble fault propagation folds; this suggests upward propagation of reactivated buried faults, promoted by diking. These results suggest that fault growth and graben development, as well as the longer-term evolution of the axis of MDPB, may be explained only through dike emplacement and that any amagmatic faulting is not necessary.

  2. Detection of Eccentricity Faults in Five-Phase Ferrite-PM Assisted Synchronous Reluctance Machines

    National Research Council Canada - National Science Library

    Carlos López-Torres; Jordi-Roger Riba; Antonio Garcia; Luís Romeral

    2017-01-01

    ... (zero-sequence voltage component). However, there is a lack of research dealing with the topic of fault diagnosis in multi-phase PMa-SynRMs, and in particular, those focused on detecting eccentricity faults...

  3. Fault detection and diagnosis in a spacecraft attitude determination system

    Science.gov (United States)

    Pirmoradi, F. N.; Sassani, F.; de Silva, C. W.

    2009-09-01

    This paper presents a new scheme for fault detection and diagnosis (FDD) in spacecraft attitude determination (AD) sensors. An integrated attitude determination system, which includes measurements of rate and angular position using rate gyros and vector sensors, is developed. Measurement data from all sensors are fused by a linearized Kalman filter, which is designed based on the system kinematics, to provide attitude estimation and the values of the gyro bias. Using this information the erroneous sensor measurements are corrected, and unbounded sensor measurement errors are avoided. The resulting bias-free data are used in the FDD scheme. The FDD algorithm uses model-based state estimation, combining the information from the rotational dynamics and kinematics of a spacecraft with the sensor measurements to predict the future sensor outputs. Fault isolation is performed through extended Kalman filters (EKFs). The innovation sequences of EKFs are monitored by several statistical tests to detect the presence of a failure and to localize the failures in all AD sensors. The isolation procedure is developed in two phases. In the first phase, two EKFs are designed, which use subsets of measurements to provide state estimates and form residuals, which are used to verify the source of the fault. In the second phase of isolation, testing of multiple hypotheses is performed. The generalized likelihood ratio test is utilized to identify the faulty components. In the scheme developed in this paper a relatively small number of hypotheses is used, which results in faster isolation and highly distinguishable fault signatures. An important feature of the developed FDD scheme is that it can provide attitude estimations even if only one type of sensors is functioning properly.

  4. Active tectonics west of New Zealand's Alpine Fault: South Westland Fault Zone activity shows Australian Plate instability

    Science.gov (United States)

    De Pascale, Gregory P.; Chandler-Yates, Nicholas; Dela Pena, Federico; Wilson, Pam; May, Elijah; Twiss, Amber; Cheng, Che

    2016-04-01

    The 300 km long South Westland Fault Zone (SWFZ) is within the footwall of the Central Alpine Fault (Holocene sediments and gentle hanging wall anticlinal folding. Cone penetration test (CPT) stratigraphy shows repeated sequences within the fault scarp (consistent with thrusting). Optically stimulated luminescence (OSL) dating constrains the most recent rupture post-12.1 ± 1.7 ka with evidence for three to four events during earthquakes of at least Mw 6.8. This study shows significant deformation is accommodated on poorly characterized Australian Plate structures northwest of the Alpine Fault and demonstrates that major active and seismogenic structures remain uncharacterized in densely forested regions on Earth.

  5. Detection and treatment of faults in manufacturing systems based on Petri Nets

    OpenAIRE

    Riascos, L. A. M.; Moscato, L. A.; Miyagi, P. E.

    2004-01-01

    This paper introduces a methodology for modeling and analyzing fault-tolerant manufacturing systems that not only optimizes normal productive processes, but also performs detection and treatment of faults. This approach is based on the hierarchical and modular integration of Petri Nets. The modularity provides the integration of three types of processes: those representing the productive process, fault detection, and fault treatment. The hierarchical aspect of the approach permits us to consi...

  6. Fault Detection for a Butterfly Unit in an FFT Processor(Letter : Special Issue on Fault-Tolerant Systems)

    OpenAIRE

    Tsunoyama, Masahiro; Ookuma, Satoshi; Naito, Sachio

    1990-01-01

    This letter proposes a concurrent fault detection scheme for a butterfly unit in an FFT processor. A fault in a butterfly unit is detected by recomuting. Input data to the butterfly unit is coded by a bit rotation and used for recomputing. The recomputed outputs are decoded and compared with the output for the first computation. The hardware overhead for the scheme is O(N) and the time overhead is O(log (N)) where N is the number of input data.

  7. Fault Diagnosis for Actuators in a Class of Nonlinear Systems Based on an Adaptive Fault Detection Observer

    Directory of Open Access Journals (Sweden)

    Runxia Guo

    2016-01-01

    Full Text Available The problem of actuators’ fault diagnosis is pursued for a class of nonlinear control systems that are affected by bounded measurement noise and external disturbances. A novel fault diagnosis algorithm has been proposed by combining the idea of adaptive control theory and the approach of fault detection observer. The asymptotical stability of the fault detection observer is guaranteed by setting the adaptive adjusting law of the unknown fault vector. A theoretically rigorous proof of asymptotical stability has been given. Under the condition that random measurement noise generated by the sensors of control systems and external disturbances exist simultaneously, the designed fault diagnosis algorithm is able to successfully give specific estimated values of state variables and failures rather than just giving a simple fault warning. Moreover, the proposed algorithm is very simple and concise and is easy to be applied to practical engineering. Numerical experiments are carried out to evaluate the performance of the fault diagnosis algorithm. Experimental results show that the proposed diagnostic strategy has a satisfactory estimation effect.

  8. Active Fault Diagnosis for Hybrid Systems Based on Sensitivity Analysis and EKF

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Bak, Thomas

    2011-01-01

    An active fault diagnosis approach for different kinds of faults is proposed. The input of the approach is designed off-line based on sensitivity analysis such that the maximum sensitivity for each individual system parameter is obtained. Using maximum sensitivity, results in a better precision...... in the estimation of the corresponding parameter. The fault detection and isolation is done by comparing the nominal parameters with those estimated by Extended Kalman Filter (EKF). In study, Gaussian noise is used as the input disturbance as well as the measurement noise for simulation. The method is implemented...

  9. Double Fault Detection of Cone-Shaped Redundant IMUs Using Wavelet Transformation and EPSA

    Directory of Open Access Journals (Sweden)

    Wonhee Lee

    2014-02-01

    Full Text Available A model-free hybrid fault diagnosis technique is proposed to improve the performance of single and double fault detection and isolation. This is a model-free hybrid method which combines the extended parity space approach (EPSA with a multi-resolution signal decomposition by using a discrete wavelet transform (DWT. Conventional EPSA can detect and isolate single and double faults. The performance of fault detection and isolation is influenced by the relative size of noise and fault. In this paper; the DWT helps to cancel the high frequency sensor noise. The proposed technique can improve low fault detection and isolation probability by utilizing the EPSA with DWT. To verify the effectiveness of the proposed fault detection method Monte Carlo numerical simulations are performed for a redundant inertial measurement unit (RIMU.

  10. A Soft Technique for Fault Detection and Identification in Mechanical Systems

    Directory of Open Access Journals (Sweden)

    Sunan HUANG

    2008-10-01

    Full Text Available There are two approaches to diagnose a fault for mechanical systems: add hardware sensors, design software algorithms. This paper will focus on software approach to detect and identify a class of faults. The proposed approach uses an estimator built to enable the detection of fault occurrences through comparison of observed states with available sensor information, while other nonlinear estimator is used to identify the fault extracting its signature. Advantages of the proposed fault detection and identification methods are that they are based on the established dynamic model, they do not require acceleration measurements. Experimental study is given to illustrate the effects of the proposed approach.

  11. Improvement of Matrix Converter Drive Reliability by Online Fault Detection and a Fault-Tolerant Switching Strategy

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem; Liu, Tian-Hua; Chen, Der-Fa

    2011-01-01

    The matrix converter system is becoming a very promising candidate to replace the conventional two-stage ac/dc/ac converter, but system reliability remains an open issue. The most common reliability problem is that a bidirectional switch has an open-switch fault during operation. In this paper......, a matrix converter driving a speed-controlled permanent-magnet synchronous motor is examined under a single open-switch fault. First, a new fault-detection method is proposed using only the motor currents. Second, a novel fault-tolerant switching strategy is presented. By treating the matrix converter...... as a two-stage rectifier/inverter, existing modulation techniques for the inverter stage can be reused, whereas the rectifier stage is modified by control to counteract the fault. However, the proposed techniques require no additional hardware devices or circuit modifications to the matrix converter...

  12. Guaranteed robust fault detection and isolation techniques for small satellites

    Science.gov (United States)

    Valavani, L.; Tantouris, N.

    2013-12-01

    The paper presents two generic fault detection and isolation (FDI) techniques which have shown remarkable robustness when applied to the SIMULINK model of a small satellite for thruster failures. While fundamentally different in their design approach, they both generate ʽstructured residuals' which accurately capture the failure mode. The diagnosis criterion in both methods relies on residuals direction rather than magnitude, which avoids the delays and expense of setting accurate thresholds for residuals magnitudes. Most importantly, this fact can account for the enhanced robustness to disturbances and sensor noise, as well as to significant parametric variations. Extensive Monte Carlo simulations are presented validating the robust performance of the two algorithms.

  13. Residual signal feature extraction for gearbox planetary stage fault detection

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Ursin, Thomas; Sweeney, Christian Walsted

    2017-01-01

    Faults in planetary gears and related bearings, e.g. planet bearings and planet carrier bearings, pose inherent difficulties on their accurate and consistent detection associated mainly to the low energy in slow rotating stages and the operating complexity of planetary gearboxes. In this work......, statistical features measuring the signal energy and Gaussianity are calculated from the residual signals between each pair from the first to the fifth tooth mesh frequency of the meshing process in a multi-stage wind turbine gearbox. The suggested algorithm includes resampling from time to angular domain...

  14. Geodynamics of the Dead Sea Fault: Do active faulting and past earthquakes determine the seismic gaps?

    Science.gov (United States)

    Meghraoui, Mustapha

    2014-05-01

    The ~1000-km-long North-South trending Dead Sea transform fault (DSF) presents structural discontinuities and includes segments that experienced large earthquakes (Mw>7) in historical times. The Wadi Araba and Jordan Valley, the Lebanese restraining bend, the Missyaf and Ghab fault segments in Syria and the Ziyaret Fault segment in Turkey display geometrical complexities made of step overs, restraining and releasing bends that may constitute major obstacles to earthquake rupture propagation. Using active tectonics, GPS measurements and paleoseismology we investigate the kinematics and long-term/short term slip rates along the DSF. Tectonic geomorphology with paleoseismic trenching and archeoseismic investigations indicate repeated faulting events and left-lateral slip rate ranging from 4 mm/yr in the southern fault section to 6 mm/yr in the northern fault section. Except for the northernmost DSF section, these estimates of fault slip rate are consistent with GPS measurements that show 4 to 5 mm/yr deformation rate across the plate boundary. However, recent GPS results showing ~2.5 mm/yr velocity rate of the northern DSF appears to be quite different than the ~6 mm/yr paleoseismic slip rate. The kinematic modeling that combines GPS and seismotectonic results implies a complex geodynamic pattern where the DSF transforms the Cyprus arc subduction zone into transpressive tectonics on the East Anatolian fault. The timing of past earthquake ruptures shows the occurrence of seismic sequences and a southward migration of large earthquakes, with the existence of major seismic gaps along strike. In this paper, we discuss the role of the DSF in the regional geodynamics and its implication on the identification of seismic gaps.

  15. Active Fault Diagnosis in Sampled-data Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2015-01-01

    The focus in this paper is on active fault diagnosis (AFD) in closed-loop sampleddata systems. Applying the same AFD architecture as for continuous-time systems does not directly result in the same set of closed-loop matrix transfer functions. For continuous-time systems, the LFT (linear fractional...... transformation) structure in the connection between the parametric faults and the matrix transfer function (also known as the fault signature matrix) applied for AFD is not directly preserved for sampled-data system. As a consequence of this, the AFD methods cannot directly be applied for sampled-data systems....... Two methods are considered in this paper to handle the fault signature matrix for sampled-data systems such that standard AFD methods can be applied. The first method is based on a discretization of the system such that the LFT structure is preserved resulting in the same LFT structure in the fault...

  16. Patterns of fault interactions triggered by micro earthquake activity

    Science.gov (United States)

    Mouslopoulou, Vasiliki; Hristopulos, Dionisis

    2010-05-01

    Historical earthquakes are often strongly clustered in space and time. This clustering has been attributed to static stress triggering associated with tectonic fault interactions and/or fluid migration. Discrimination between these two models requires detailed information on the timing, location and size of earthquakes. The Matata earthquake sequence, which occurred within the active Taupo Rift in New Zealand, provides a unique opportunity to chart spatial and temporal patterns of earthquakes along individual faults, between neighbouring faults and within the entire fault system over timescales of days to years. This is due to the accurate relocation of 2563 small to moderate size earthquakes (15.5) that occurred over thousand-year timescales (e.g. <60 kyr). Therefore, if the origin of small-to-moderate-sized earthquakes in the rift is indeed tectonic and fault interaction is a scale invariant process, it may be possible to constrain better the occurrence of large earthquakes by analysing widely available microearthquake data.

  17. Detecting Hidden Faults and Other Lineations with UAVSAR

    Science.gov (United States)

    Parker, J. W.; Glasscoe, M. T.; Donnellan, A.

    2013-12-01

    Jay Parker, Margaret Glasscoe, Andrea Donnellan Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA The M7.2 El Mayor Cucapah Earthquake of April 4, 2010 is the main earthquake to date observed by the NASA UAVSAR. By observing with repeat passes (October 2009, April 2010 captures the coseismic strain pattern, and subsequent flights capture the postseismic process) over the adjoining portion of California, the interferometric phase maps of geodetic displacements are exceptionally high definition (pixel size is roughly 7 m) records of the extended deformation field from the earthquake process, including revelation of a rich network of plate parallel and conjugate faulting, apparently slipping sympathetically to the earthquake-induced quasistatic changes in stress. While the most significant of these faults have been documented by cooperative use of UAVSAR maps and field research, a subsequent opportunity arises: to use this data to develop and validate an automated approach to detecting faults and other lineations directly from the UAVSAR unwrapped phase product that corresponds to a single-component deformation map. The Canny edge detection algorithm is employed, after a preparation stage to clean the data. This preprocessing step is tailored to the nature of the radar phase data: data dropouts in single pixels and extended areas (blown sand dunes, farms) are a much larger problem than background white noise. Blocks of typically 3x3 pixels are currently reduced to a single value, the average after bad pixels are discarded. The smoothing methods typically used with the Canny method are minimized (smoothing makes data drop-out problems worse). The aperture size that determines a gradient estimation is chosen large (7 vs. the typical 3), as this is found to produce continuous (rather than dashed) lineations. The main Canny threshold is chosen to correspond to a user selected slip threshold in mm. Reasonable maps of lineations in the Salton

  18. Neural adaptive observer-based sensor and actuator fault detection in nonlinear systems: Application in UAV.

    Science.gov (United States)

    Abbaspour, Alireza; Aboutalebi, Payam; Yen, Kang K; Sargolzaei, Arman

    2017-03-01

    A new online detection strategy is developed to detect faults in sensors and actuators of unmanned aerial vehicle (UAV) systems. In this design, the weighting parameters of the Neural Network (NN) are updated by using the Extended Kalman Filter (EKF). Online adaptation of these weighting parameters helps to detect abrupt, intermittent, and incipient faults accurately. We apply the proposed fault detection system to a nonlinear dynamic model of the WVU YF-22 unmanned aircraft for its evaluation. The simulation results show that the new method has better performance in comparison with conventional recurrent neural network-based fault detection strategies. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Fault Detection and Isolation Using Analytical Redundancy Relations for the Ship Propulsion Benchmark

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh

    The prime objective of Fault-tolerant Control (FTC) systems is to handle faults and discrepancies using appropriate accommodation policies. The issue of obtaining information about various parameters and signals, which have to be monitored for fault detection purposes, becomes a rigorous task...... is illustrated on the ship propulsion benchmark....

  20. FAULT DETECTION AND LOCALIZATION IN MOTORCYCLES BASED ON THE CHAIN CODE OF PSEUDOSPECTRA AND ACOUSTIC SIGNALS

    Directory of Open Access Journals (Sweden)

    B. S. Anami

    2013-06-01

    Full Text Available Vehicles produce sound signals with varying temporal and spectral properties under different working conditions. These sounds are indicative of the condition of the engine. Fault diagnosis is a significantly difficult task in geographically remote places where expertise is scarce. Automated fault diagnosis can assist riders to assess the health condition of their vehicles. This paper presents a method for fault detection and location in motorcycles based on the chain code of the pseudospectra and Mel-frequency cepstral coefficient (MFCC features of acoustic signals. The work comprises two stages: fault detection and fault location. The fault detection stage uses the chain code of the pseudospectrum as a feature vector. If the motorcycle is identified as faulty, the MFCCs of the same sample are computed and used as features for fault location. Both stages employ dynamic time warping for the classification of faults. Five types of faults in motorcycles are considered in this work. Observed classification rates are over 90% for the fault detection stage and over 94% for the fault location stage. The work identifies other interesting applications in the development of acoustic fingerprints for fault diagnosis of machinery, tuning of musical instruments, medical diagnosis, etc.

  1. Fault Detection and Isolation for a Supermarket Refrigeration System - Part One

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Rasmussen, Karsten B.; Kieu, Anh T.

    2011-01-01

    Fault Detection and Isolation (FDI) using the Kalman Filter (KF) technique for a supermarket refrigeration system is explored. Four types of sensor fault scenarios, namely drift, offset, freeze and hard-over, are considered for two temperature sensors, and one type of parametric fault scenario...

  2. Stochastic Resonance algorithms to enhance damage detection in bearing faults

    Directory of Open Access Journals (Sweden)

    Castiglione Roberto

    2015-01-01

    Full Text Available Stochastic Resonance is a phenomenon, studied and mainly exploited in telecommunication, which permits the amplification and detection of weak signals by the assistance of noise. The first papers on this technique are dated early 80 s and were developed to explain the periodically recurrent ice ages. Other applications mainly concern neuroscience, biology, medicine and obviously signal analysis and processing. Recently, some researchers have applied the technique for detecting faults in mechanical systems and bearings. In this paper, we try to better understand the conditions of applicability and which is the best algorithm to be adopted for these purposes. In fact, to get the methodology profitable and efficient to enhance the signal spikes due to fault in rings and balls/rollers of bearings, some parameters have to be properly selected. This is a problem since in system identification this procedure should be as blind as possible. Two algorithms are analysed: the first exploits classical SR with three parameters mutually dependent, while the other uses Woods-Saxon potential, with three parameters yet but holding a different meaning. The comparison of the performances of the two algorithms and the optimal choice of their parameters are the scopes of this paper. Algorithms are tested on simulated and experimental data showing an evident capacity of increasing the signal to noise ratio.

  3. Fault detection in processes represented by PLS models using an EWMA control scheme

    KAUST Repository

    Harrou, Fouzi

    2016-10-20

    Fault detection is important for effective and safe process operation. Partial least squares (PLS) has been used successfully in fault detection for multivariate processes with highly correlated variables. However, the conventional PLS-based detection metrics, such as the Hotelling\\'s T and the Q statistics are not well suited to detect small faults because they only use information about the process in the most recent observation. Exponentially weighed moving average (EWMA), however, has been shown to be more sensitive to small shifts in the mean of process variables. In this paper, a PLS-based EWMA fault detection method is proposed for monitoring processes represented by PLS models. The performance of the proposed method is compared with that of the traditional PLS-based fault detection method through a simulated example involving various fault scenarios that could be encountered in real processes. The simulation results clearly show the effectiveness of the proposed method over the conventional PLS method.

  4. On Real-Time Fault Detection in Wind Turbines: Sensor Selection Algorithm and Detection Time Reduction Analysis

    Directory of Open Access Journals (Sweden)

    Francesc Pozo

    2016-07-01

    Full Text Available In this paper, we address the problem of real-time fault detection in wind turbines. Starting from a data-driven fault detection method, the contribution of this paper is twofold. First, a sensor selection algorithm is proposed with the goal to reduce the computational effort of the fault detection method. Second, an analysis is performed to reduce the data acquisition time needed by the fault detection method, that is, with the goal of reducing the fault detection time. The proposed methods are tested in a benchmark wind turbine where different actuator and sensor failures are simulated. The results demonstrate the performance and effectiveness of the proposed algorithms that dramatically reduce the number of sensors and the fault detection time.

  5. Bearing fault detection in the acoustic emission frequency range

    Science.gov (United States)

    Tavakoli, Massoud S.

    The effectiveness of using bearing fault detection in the acoustic-emission frequency range is demonstrated using a vertical milling machine as the testbed. The experimental testbed is monitored by an accelerometer and an acoustic emission sensor, and the signals are demodulated by rms enveloping and then fast-Fourier-transformed. The analytical computation of the defect characteristic frequency is explained, and the time histories are given of the enveloped signal and its spectrum. The method is shown to be useful for extracting the repetition rate of the repetitive component of the general signal, and the signal generated by the bearing defect is identified in the frequency ranges of mechanical vibration and acoustic emission. The signal in the acoustic-emission frequency range is shown to be helpful for detecting bearing defects because it not affected by repetitive mechanical noise.

  6. Fault detection and fault tolerant control of a smart base isolation system with magneto-rheological damper

    Science.gov (United States)

    Wang, Han; Song, Gangbing

    2011-08-01

    Fault detection and isolation (FDI) in real-time systems can provide early warnings for faulty sensors and actuator signals to prevent events that lead to catastrophic failures. The main objective of this paper is to develop FDI and fault tolerant control techniques for base isolation systems with magneto-rheological (MR) dampers. Thus, this paper presents a fixed-order FDI filter design procedure based on linear matrix inequalities (LMI). The necessary and sufficient conditions for the existence of a solution for detecting and isolating faults using the H_{\\infty } formulation is provided in the proposed filter design. Furthermore, an FDI-filter-based fuzzy fault tolerant controller (FFTC) for a base isolation structure model was designed to preserve the pre-specified performance of the system in the presence of various unknown faults. Simulation and experimental results demonstrated that the designed filter can successfully detect and isolate faults from displacement sensors and accelerometers while maintaining excellent performance of the base isolation technology under faulty conditions.

  7. The electrical activity of stacking faults in Czochralski silicon

    Science.gov (United States)

    Castaldini, A.; Cavallini, A.; Poggi, A.; Susi, E.

    1989-05-01

    A spectroscopic analysis by the light-beam-induced-current technique has been carried out to study the electrical properties of stacking faults in Czochralski silicon subjected to internal gettering treatments. By changing the wavelength of the light beam probing the sample, we have obtained the depth profiling of the stacking fault electrical activity. Occurrence of minority carrier recombination and generation processes at some stacking faults, corresponding, respectively, to dark and bright levels in a grey-shade imaging, has been observed. The presence of fixed charges at the defect-silicon matrix interface is hypothesized as a possible cause of the observed images.

  8. Modeling, Detection, and Disambiguation of Sensor Faults for Aerospace Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — Sensor faults continue to be a major hurdle for sys- tems health management to reach its full potential. At the same time, few recorded instances of sensor faults...

  9. Minimal transient modes for faults detection in analogue VLSI circuits

    OpenAIRE

    KADIM H.J.

    2003-01-01

    The method introduced here uses an investigation of the dominant natural mode to identify possible abnormalities in analogue circuits due to faults and parameter variations, and determining the reliability of circuits when operating in the presence of faults.

  10. Is there really an active fault (Cibyra Fault?) cutting the Stadion of the ancient city of Cibyra? (Burdur-Fethiye Fault Zone, Turkey)

    Science.gov (United States)

    Elitez, İrem; Yaltırak, Cenk

    2013-04-01

    The Cibyra segment of the Burdur-Fethiye Fault Zone (BFFZ) is in a tectonically very active region of southwestern Anatolia. The presence of the Cibyra Fault was firstly suggested by Akyüz and Altunel (1997, 2001). Researchers identified traces of historical earthquakes in Cibyra by taking into account the collapsed seat rows on the east side of the stadion as reference. They claimed that the NNE-SSW left lateral fault Cibyra Fault (related to Burdur-Fethiye Fault Zone) continues through Pliocene sediments on both eastern and western sides of the stadion of Cibyra. The questionable left-lateral fault had been examined in detail by ourselves during our 60-days accommodation in the ancient city of Cibyra excavations for the Burdur-Fethiye Fault Zone Project in 2008, 2009 and 2012. A left-lateral offset on the Stadion was firstly mentioned in a study whose aim is to find the traces of Burdur-Fethiye Fault (Akyüz and Altunel, 2001) and many researchers accepted this fault by reference (for example Alçiçek et al. 2002, 2004, 2005, 2006 and Karabacak, 2011). However as a result of the field observations it is understood that there is no fault cutting the Stadion. By the reason of the fact that there are a lot of faults in the region, however the fault that devastated the ancient city is unknown. The deformation traces on the ruins of the ancient city display a seismic movement occured in the region. It is strongly possible that this movement is related to the NE-SW left lateral oblique normal fault named as Cibyra Fault at the northwestern side of the city. Especially the ravages in the eastern part of the city indicate that the deformations are related to ground properties. If the rotation and overturn movement are considered and if both movements are the product of the same earthquake, the real Cibyra Fault is compatible with normal fault with left lateral compenent. After the 2011 excavations and 2012 field studies, the eastern wall of the Stadion showed that

  11. Research on Fault Detection System of Power Equipment Based on UV and Infrared Image

    Science.gov (United States)

    Lu, Qiyu; Ding, Kun

    2017-09-01

    UV corona on power system can reflect the location of the fault and the severity of the fault, the traditional UV and infrared detection equipment can only use the band and the visible light band image of the power system fault detection. In this paper, a power system fault detection system based on ultraviolet and infrared dual-band images is designed. The principle of UV imaging detection and image fusion are introduced respectively. The software of the host computer is written by MFC. The software can acquire both ultraviolet and infrared, the two images are fused using the image fusion algorithm based on edge detection and cross correlation and the highest point temperature is plotted. Experiments show that the system can detect the failure of power equipment in time, and has a certain practical value, which puts forward a new idea for fault detection of power equipment.

  12. Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids.

    Science.gov (United States)

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong

    2017-04-28

    Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility model, the suspicious sensor is then chosen to launch fault diagnosis requests. Secondly, the sending time of fault diagnosis request is discussed to avoid the transmission overhead brought about by unnecessary diagnosis requests and improve the efficiency of fault detection based on neighbor cooperation. The diagnosis reply of a neighbor sensor is analyzed according to its own status. Finally, to further improve the accuracy of fault detection, the diagnosis results of neighbors are divided into several classifications to judge the fault status of the sensors which launch the fault diagnosis requests. Simulation results show that this novel mechanism can achieve high fault detection ratio with a small number of fault diagnoses and low data congestion probability.

  13. Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids

    Science.gov (United States)

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong

    2017-01-01

    Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility model, the suspicious sensor is then chosen to launch fault diagnosis requests. Secondly, the sending time of fault diagnosis request is discussed to avoid the transmission overhead brought about by unnecessary diagnosis requests and improve the efficiency of fault detection based on neighbor cooperation. The diagnosis reply of a neighbor sensor is analyzed according to its own status. Finally, to further improve the accuracy of fault detection, the diagnosis results of neighbors are divided into several classifications to judge the fault status of the sensors which launch the fault diagnosis requests. Simulation results show that this novel mechanism can achieve high fault detection ratio with a small number of fault diagnoses and low data congestion probability. PMID:28452925

  14. Active Fault Tolerant Control of Livestock Stable Ventilation System

    DEFF Research Database (Denmark)

    Gholami, Mehdi

    2011-01-01

    degraded performance even in the faulty case. In this thesis, we have designed such controllers for climate control systems for livestock buildings in three steps: Deriving a model for the climate control system of a pig-stable. Designing a active fault diagnosis (AFD) algorithm for different kinds......). In the FTC part of the thesis, first a passive fault tolerant controller (PFTC) based on state feed-back is proposed for discretetime PWA systems. only actuator faults are considered. By dissipativity theory and H1 analysis, the problem is cast as a set of linear matrix inequalities (LMIs). In the next...... contribution, the problem of reconfigurability of PWA systems is evaluated. A system subject to a fault is considered as reconfigurable if it can be stabilized by a state feedback controller and the optimal cost of the performance of the systems is admissible. In the previous methods the input constraints...

  15. Fault Detection of Bearing Systems through EEMD and Optimization Algorithm.

    Science.gov (United States)

    Lee, Dong-Han; Ahn, Jong-Hyo; Koh, Bong-Hwan

    2017-10-28

    This study proposes a fault detection and diagnosis method for bearing systems using ensemble empirical mode decomposition (EEMD) based feature extraction, in conjunction with particle swarm optimization (PSO), principal component analysis (PCA), and Isomap. First, a mathematical model is assumed to generate vibration signals from damaged bearing components, such as the inner-race, outer-race, and rolling elements. The process of decomposing vibration signals into intrinsic mode functions (IMFs) and extracting statistical features is introduced to develop a damage-sensitive parameter vector. Finally, PCA and Isomap algorithm are used to classify and visualize this parameter vector, to separate damage characteristics from healthy bearing components. Moreover, the PSO-based optimization algorithm improves the classification performance by selecting proper weightings for the parameter vector, to maximize the visualization effect of separating and grouping of parameter vectors in three-dimensional space.

  16. Fault Detection of Bearing Systems through EEMD and Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Dong-Han Lee

    2017-10-01

    Full Text Available This study proposes a fault detection and diagnosis method for bearing systems using ensemble empirical mode decomposition (EEMD based feature extraction, in conjunction with particle swarm optimization (PSO, principal component analysis (PCA, and Isomap. First, a mathematical model is assumed to generate vibration signals from damaged bearing components, such as the inner-race, outer-race, and rolling elements. The process of decomposing vibration signals into intrinsic mode functions (IMFs and extracting statistical features is introduced to develop a damage-sensitive parameter vector. Finally, PCA and Isomap algorithm are used to classify and visualize this parameter vector, to separate damage characteristics from healthy bearing components. Moreover, the PSO-based optimization algorithm improves the classification performance by selecting proper weightings for the parameter vector, to maximize the visualization effect of separating and grouping of parameter vectors in three-dimensional space.

  17. Gyro-based Maximum-Likelihood Thruster Fault Detection and Identification

    Science.gov (United States)

    Wilson, Edward; Lages, Chris; Mah, Robert; Clancy, Daniel (Technical Monitor)

    2002-01-01

    When building smaller, less expensive spacecraft, there is a need for intelligent fault tolerance vs. increased hardware redundancy. If fault tolerance can be achieved using existing navigation sensors, cost and vehicle complexity can be reduced. A maximum likelihood-based approach to thruster fault detection and identification (FDI) for spacecraft is developed here and applied in simulation to the X-38 space vehicle. The system uses only gyro signals to detect and identify hard, abrupt, single and multiple jet on- and off-failures. Faults are detected within one second and identified within one to five accords,

  18. Verification of a Novel Method of Detecting Faults in Medium-Voltage Systems with Covered Conductors

    Directory of Open Access Journals (Sweden)

    Mišák Stanislav

    2017-06-01

    Full Text Available This paper describes the use of new methods of detecting faults in medium-voltage overhead lines built of covered conductors. The methods mainly address such faults as falling of a conductor, contacting a conductor with a tree branch, or falling a tree branch across three phases of a medium-voltage conductor. These faults cannot be detected by current digital relay protection systems. Therefore, a new system that can detect the above mentioned faults was developed. After having tested its operation, the system has already been implemented to protect mediumvoltage overhead lines built of covered conductors.

  19. The relationship of near-surface active faulting to megathrust splay fault geometry in Prince William Sound, Alaska

    Science.gov (United States)

    Finn, S.; Liberty, L. M.; Haeussler, P. J.; Northrup, C.; Pratt, T. L.

    2010-12-01

    We interpret regionally extensive, active faults beneath Prince William Sound (PWS), Alaska, to be structurally linked to deeper megathrust splay faults, such as the one that ruptured in the 1964 M9.2 earthquake. Western PWS in particular is unique; the locations of active faulting offer insights into the transition at the southern terminus of the previously subducted Yakutat slab to Pacific plate subduction. Newly acquired high-resolution, marine seismic data show three seismic facies related to Holocene and older Quaternary to Tertiary strata. These sediments are cut by numerous high angle normal faults in the hanging wall of megathrust splay. Crustal-scale seismic reflection profiles show splay faults emerging from 20 km depth between the Yakutat block and North American crust and surfacing as the Hanning Bay and Patton Bay faults. A distinct boundary coinciding beneath the Hinchinbrook Entrance causes a systematic fault trend change from N30E in southwestern PWS to N70E in northeastern PWS. The fault trend change underneath Hinchinbrook Entrance may occur gradually or abruptly and there is evidence for similar deformation near the Montague Strait Entrance. Landward of surface expressions of the splay fault, we observe subsidence, faulting, and landslides that record deformation associated with the 1964 and older megathrust earthquakes. Surface exposures of Tertiary rocks throughout PWS along with new apatite-helium dates suggest long-term and regional uplift with localized, fault-controlled subsidence.

  20. The Lake Edgar Fault: an active fault in Southwestern Tasmania, Australia, with repeated displacement in the Quaternary

    Directory of Open Access Journals (Sweden)

    V. Jensen

    2003-06-01

    Full Text Available The Lake Edgar Fault in Western Tasmania, Australia is marked by a prominent fault scarp and is a recently reactivated fault initially of Cambrian age. The scarp has a northerly trend and passes through the western abutment of the Edgar Dam, a saddle dam on Lake Pedder. The active fault segment displaces geologically young river and glacial deposits. It is 29 ± 4 km long, and dips to the west. Movement on the fault has ruptured the ground surface at least twice within the Quaternary and possibly the last ca. 25 000 years; the most recent rupture has occurred since the last glaciation (within the last ca. 10000 years. This is the only known case of surface faulting in Australia with evidence for repeated ruptures in the Late Pleistocene. Along its central portion the two most recent surface-faulting earthquakes have resulted in about 2.5 m of vertical displacement each (western side up. The Lake Edgar Fault is considered capable of generating earthquakes in the order of magnitude 61/2-71/4. The Gell River Fault is another fault nearby that was apparently also active in the Late Pleistocene. It has yet to be studied in detail but the scarp appears to be more degraded and therefore older than the most recent movement on the Lake Edgar Fault.

  1. Analytical Model-based Fault Detection and Isolation in Control Systems

    DEFF Research Database (Denmark)

    Vukic, Z.; Ozbolt, H.; Blanke, M.

    1998-01-01

    The paper gives an introduction and an overview of the field of fault detection and isolation for control systems. The summary of analytical (quantitative model-based) methodds and their implementation are presented. The focus is given to mthe analytical model-based fault-detection and fault...... diagnosis methods, often viewed as the classical or deterministic ones. Emphasis is placed on the algorithms suitable for ship automation, unmanned underwater vehicles, and other systems of automatic control....

  2. Fault Detection Enhancement in Rolling Element Bearings via Peak-Based Multiscale Decomposition and Envelope Demodulation

    OpenAIRE

    Hua-Qing Wang; Wei Hou; Gang Tang; Hong-Fang Yuan; Qing-Liang Zhao; Xi Cao

    2014-01-01

    Vibration signals of rolling element bearings faults are usually immersed in background noise, which makes it difficult to detect the faults. Wavelet-based methods being used commonly can reduce some types of noise, but there is still plenty of room for improvement due to the insufficient sparseness of vibration signals in wavelet domain. In this work, in order to eliminate noise and enhance the weak fault detection, a new kind of peak-based approach combined with multiscale decomposition and...

  3. On Line Current Monitoring and Application of a Residual Method for Eccentricity Fault Detection

    Directory of Open Access Journals (Sweden)

    METATLA, A.

    2011-02-01

    Full Text Available This work concerns the monitoring and diagnosis of faults in induction motors. We develop an approach based on residual analysis of stator currents to detect and diagnose faults eccentricity static, dynamic and mixed in three phase induction motor. To simulate the behavior of motor failure, a model is proposed based on the approach of magnetically coupled coils. The simulation results show the importance of the approach applied for the detection and diagnosis of fault in three phase induction motor.

  4. Machine Fault Detection Based on Filter Bank Similarity Features Using Acoustic and Vibration Analysis

    Directory of Open Access Journals (Sweden)

    Mauricio Holguín-Londoño

    2016-01-01

    Full Text Available Vibration and acoustic analysis actively support the nondestructive and noninvasive fault diagnostics of rotating machines at early stages. Nonetheless, the acoustic signal is less used because of its vulnerability to external interferences, hindering an efficient and robust analysis for condition monitoring (CM. This paper presents a novel methodology to characterize different failure signatures from rotating machines using either acoustic or vibration signals. Firstly, the signal is decomposed into several narrow-band spectral components applying different filter bank methods such as empirical mode decomposition, wavelet packet transform, and Fourier-based filtering. Secondly, a feature set is built using a proposed similarity measure termed cumulative spectral density index and used to estimate the mutual statistical dependence between each bandwidth-limited component and the raw signal. Finally, a classification scheme is carried out to distinguish the different types of faults. The methodology is tested in two laboratory experiments, including turbine blade degradation and rolling element bearing faults. The robustness of our approach is validated contaminating the signal with several levels of additive white Gaussian noise, obtaining high-performance outcomes that make the usage of vibration, acoustic, and vibroacoustic measurements in different applications comparable. As a result, the proposed fault detection based on filter bank similarity features is a promising methodology to implement in CM of rotating machinery, even using measurements with low signal-to-noise ratio.

  5. A Survey on Distributed Filtering and Fault Detection for Sensor Networks

    Directory of Open Access Journals (Sweden)

    Hongli Dong

    2014-01-01

    Full Text Available In recent years, theoretical and practical research on large-scale networked systems has gained an increasing attention from multiple disciplines including engineering, computer science, and mathematics. Lying in the core part of the area are the distributed estimation and fault detection problems that have recently been attracting growing research interests. In particular, an urgent need has arisen to understand the effects of distributed information structures on filtering and fault detection in sensor networks. In this paper, a bibliographical review is provided on distributed filtering and fault detection problems over sensor networks. The algorithms employed to study the distributed filtering and detection problems are categorised and then discussed. In addition, some recent advances on distributed detection problems for faulty sensors and fault events are also summarized in great detail. Finally, we conclude the paper by outlining future research challenges for distributed filtering and fault detection for sensor networks.

  6. Geotechnical and geomechanical characterization of the "fault gouge" of the "Alhama de Murcia" active fault, SE Spain.

    Science.gov (United States)

    Rodriguez-Soto, Pablo; Tsige, Meaza; Insua-Arevalo, Juan M.; Martinez-Diaz, Jose J.; Rodriguez-Escudero, Emilio; Jurado, M. ª Jose; Crespo, Elena; Jiménez Molina, David

    2017-04-01

    Here we present the results of the mechanical and mineralogical study of the fault rock of the Alhama de Murcia fault. This fault is one of the most active faults in the Iberian Peninsula. It shows segments partially formed by exhumed fine grained fault rocks (fault gouge FG) with a thickness of more than 50 m developed mainly in a brittle regime. Several strength and strain tests have been carried out, both in-situ and in laboratory, considering different stress orientations in relation to the tectonic fabric. Undisturbed samples encountered from two fault observatory boreholes drilled near Lorca, (FAM-1 and FAMSIS-IGN, of 174 and 40 m depth, respectively) has been used for the laboratory tests. The FG shows a hard soil and soft rock like mechanical behavior with uniaxial compressive strength 1.19) for planes unfavourably oriented.

  7. Fault tolerant control of a three-phase three-wire shunt active filter system based on reliability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Poure, P. [Laboratoire d' Instrumentation Electronique de Nancy LIEN, EA 3440, Nancy-Universite, Faculte des Sciences et Techniques, BP 239, 54506 Vandoeuvre Cedex (France); Weber, P.; Theilliol, D. [Centre de Recherche en Automatique de Nancy UMR 7039, Nancy-Universite, CNRS, Faculte des Sciences et Techniques, BP 239, 54506 Vandoeuvre Cedex (France); Saadate, S. [Groupe de Recherches en Electrotechnique et Electronique de Nancy UMR 7037, Nancy-Universite, CNRS, Faculte des Sciences et Techniques, BP 239, 54506 Vandoeuvre Cedex (France)

    2009-02-15

    This paper deals with fault tolerant shunt three-phase three-wire active filter topologies for which reliability is very important in industry applications. The determination of the optimal reconfiguration structure among various ones with or without redundant components is discussed based on reliability criteria. First, the reconfiguration of the inverter is detailed and a fast fault diagnosis method for power semi-conductor or driver fault detection and compensation is presented. This method avoids false fault detection due to power semi-conductors switching. The control architecture and algorithm are studied and a fault tolerant control strategy is considered. Simulation results in open and short circuit cases validate the theoretical study. Finally, the reliability of the studied three-phase three-wire filter shunt active topologies is analyzed to determine the optimal one. (author)

  8. A Spectrum Detection Approach for Bearing Fault Signal Based on Spectral Kurtosis

    Directory of Open Access Journals (Sweden)

    Yunfeng Li

    2017-01-01

    Full Text Available According to the similarity between Morlet wavelet and fault signal and the sensitive characteristics of spectral kurtosis for the impact signal, a new wavelet spectrum detection approach based on spectral kurtosis for bearing fault signal is proposed. This method decreased the band-pass filter range and reduced the wavelet window width significantly. As a consequence, the bearing fault signal was detected adaptively, and time-frequency characteristics of the fault signal can be extracted accurately. The validity of this method was verified by the identifications of simulated shock signal and test bearing fault signal. The method provides a new understanding of wavelet spectrum detection based on spectral kurtosis for rolling element bearing fault signal.

  9. Robust Fault Detection for a Class of Uncertain Nonlinear Systems Based on Multiobjective Optimization

    Directory of Open Access Journals (Sweden)

    Bingyong Yan

    2015-01-01

    Full Text Available A robust fault detection scheme for a class of nonlinear systems with uncertainty is proposed. The proposed approach utilizes robust control theory and parameter optimization algorithm to design the gain matrix of fault tracking approximator (FTA for fault detection. The gain matrix of FTA is designed to minimize the effects of system uncertainty on residual signals while maximizing the effects of system faults on residual signals. The design of the gain matrix of FTA takes into account the robustness of residual signals to system uncertainty and sensitivity of residual signals to system faults simultaneously, which leads to a multiobjective optimization problem. Then, the detectability of system faults is rigorously analyzed by investigating the threshold of residual signals. Finally, simulation results are provided to show the validity and applicability of the proposed approach.

  10. Do mesoscale faults near the tip of an active strike-slip fault indicate regional or local stress?

    Science.gov (United States)

    Yamaji, Atsushi

    2017-04-01

    Fault-slip analysis is used in Japan after the Great Tohoku Earthquake (2011) to judge the stability of fractures in the foundations of nuclear power plants. In case a fault-slip datum from a fracture surface is explained by the present stress condition, the fracture is thought to have a risk to be activated as a fault. So, it is important to understand the relative significance of regional and local stresses. To answer the question whether mesoscale faults indicate regional or local stress, fault-slip data were collected from the walls of a trenching site of the Nojima Fault in central Japan—an active, dextral, strike-slip fault. The fault gave rise to the 1995 Kobe earthquake, which killed more than 6000 people. The trench was placed near the fault tip, which produced compressional and extensional local stress conditions on the sides of the fault near the tip. A segment of the fault, which ruptured the surface in 1995, bounded Cretaceous granite and latest Pliocene sediments in the trench. As a result, the stress inversion of the data from the mesoscale faults observed in the trench showed both the local stresses. The present WNW-ESE regional compression was found from the compressive side, but was not in the extensional side, probably because local extension surpassed the regional compression. Instead, the regional N-S compression of the Early Pleistocene was found from the extensional side. From this project, we got the lesson that fault-slip analysis reveals regional and local stresses, and that local stress sometimes masks regional one. This work was supported by a science project of "Drilling into Fault Damage Zone" (awarded to A. Lin) of the Secretariat of Nuclear Regulation Authority (Japan).

  11. Wind Turbine Fault Detection based on Artificial Neural Network Analysis of SCADA Data

    DEFF Research Database (Denmark)

    Herp, Jürgen; S. Nadimi, Esmaeil

    2015-01-01

    Slowly developing faults in wind turbine can, when not detected and fixed on time, cause severe damage and downtime. We are proposing a fault detection method based on Artificial Neural Networks (ANN) and the recordings from Supervisory Control and Data Acquisition (SCADA) systems installed in wind...

  12. Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

    Science.gov (United States)

    Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

    2007-01-01

    The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

  13. Active faulting on the Wallula fault within the Olympic-Wallowa Lineament (OWL), eastern Washington State

    Science.gov (United States)

    Sherrod, B. L.; Lasher, J. P.; Barnett, E. A.

    2013-12-01

    Several studies over the last 40 years focused on a segment of the Wallula fault exposed in a quarry at Finley, Washington. The Wallula fault is important because it is part of the Olympic-Wallowa lineament (OWL), a ~500-km-long topographic and structural lineament extending from Vancouver Island, British Columbia to Walla Walla, Washington that accommodates Basin and Range extension. The origin and nature of the OWL is of interest because it contains potentially active faults that are within 50 km of high-level nuclear waste facilities at the Hanford Site. Mapping in the 1970's and 1980's suggested the Wallula fault did not offset Holocene and late Pleistocene deposits and is therefore inactive. New exposures of the Finley quarry wall studied here suggest otherwise. We map three main packages of rocks and sediments in a ~10 m high quarry exposure. The oldest rocks are very fine grained basalts of the Columbia River Basalt Group (~13.5 Ma). The next youngest deposits include a thin layer of vesicular basalt, white volcaniclastic deposits, colluvium containing clasts of vesicular basalt, and indurated paleosols. A distinct angular unconformity separates these vesicular basalt-bearing units from overlying late Pleistocene flood deposits, two colluvium layers containing angular clasts of basalt, and Holocene tephra-bearing loess. A tephra within the loess likely correlates to nearby outcrops of Mazama ash. We recognize three styles of faults: 1) a near vertical master reverse or oblique fault juxtaposing very fine grained basalt against late Tertiary-Holocene deposits, and marked by a thick (~40 cm) vertical seam of carbonate cemented breccia; 2) subvertical faults that flatten upwards and displace late Tertiary(?) to Quaternary(?) soils, colluvium, and volcaniclastic deposits; and 3) flexural slip faults along bedding planes in folded deposits in the footwall. We infer at least two Holocene earthquakes from the quarry exposure. The first Holocene earthquake deformed

  14. New active faults on Eurasian-Arabian collision zone: Tectonic activity of Özyurt and Gülsünler faults (Eastern Anatolian Plateau, Van-Turkey)

    Energy Technology Data Exchange (ETDEWEB)

    Dicle, S.; Üner, S.

    2017-11-01

    The Eastern Anatolian Plateau emerges from the continental collision between Arabian and Eurasian plates where intense seismicity related to the ongoing convergence characterizes the southern part of the plateau. Active deformation in this zone is shared by mainly thrust and strike-slip faults. The Özyurt thrust fault and the Gülsünler sinistral strike-slip fault are newly determined fault zones, located to the north of Van city centre. Different types of faults such as thrust, normal and strike-slip faults are observed on the quarry wall excavated in Quaternary lacustrine deposits at the intersection zone of these two faults. Kinematic analysis of fault-slip data has revealed coeval activities of transtensional and compressional structures for the Lake Van Basin. Seismological and geomorphological characteristics of these faults demonstrate the capability of devastating earthquakes for the area.

  15. Fault Detection and Isolation for a Supermarket Refrigeration System - Part Two

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Rasmussen, Karsten B.; Kieu, Anh T.

    2011-01-01

    The Fault Detection and Isolation (FDI) using the Unknown Input Observer (UIO) for a supermarket refrigeration system is investigated. The original system's state $T_{goods}$ (temp. of the goods) is regarded as a system unknown input in this study, so that the FDI decision is not disturbed...... by the system uncertainties relevant to this state dynamic and the original system disturbance $Q_{airload}$ (the thermal feature of the air). It has been observed that a single UIO has a very good detection capability for concerned sensor and parametric faults. However, only the parametric fault can...... and successful FDI capability regarding to concerned fault scenarios....

  16. Fault detection of a Five-Phase Permanent-Magnet Machine

    DEFF Research Database (Denmark)

    Bianchini, Claudio; Matzen, Torben N.; Bianchi, Nicola

    2008-01-01

    The paper focuses on the fault detection of a five-phase Permanent-Magnet (PM) machine. This machine has been de-signed for fault tolerant applications, and it is characterised by a mutual inductance equal to zero and a high self inductance, with the purpose to limit the short circuit current....... The effects of a limited number of short-circuited turns were investigated by theoretical and Finite Element (FE) analysis, and then a procedure for fault detection has been proposed, focusing on the severity of the fault (i.e. the number of short-circuited turns and the related current)....

  17. From experiment to design -- Fault characterization and detection in parallel computer systems using computational accelerators

    Science.gov (United States)

    Yim, Keun Soo

    This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of

  18. Energy-Efficient Fault-Tolerant Dynamic Event Region Detection in Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Enemark, Hans-Jacob; Zhang, Yue; Dragoni, Nicola

    2015-01-01

    Fault-tolerant event detection is fundamental to wireless sensor network applications. Existing approaches usually adopt neighborhood collaboration for better detection accuracy, while need more energy consumption due to communication. Focusing on energy efficiency, this paper makes an improvement...

  19. Early Oscillation Detection for DC/DC Converter Fault Diagnosis

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

  20. Microstructural investigations on carbonate fault core rocks in active extensional fault zones from the central Apennines (Italy)

    Science.gov (United States)

    Cortinovis, Silvia; Balsamo, Fabrizio; Storti, Fabrizio

    2017-04-01

    The study of the microstructural and petrophysical evolution of cataclasites and gouges has a fundamental impact on both hydraulic and frictional properties of fault zones. In the last decades, growing attention has been payed to the characterization of carbonate fault core rocks due to the nucleation and propagation of coseismic ruptures in carbonate successions (e.g., Umbria-Marche 1997, L'Aquila 2009, Amatrice 2016 earthquakes in Central Apennines, Italy). Among several physical parameters, grain size and shape in fault core rocks are expected to control the way of sliding along the slip surfaces in active fault zones, thus influencing the propagation of coseismic ruptures during earthquakes. Nevertheless, the role of grain size and shape distribution evolution in controlling the weakening or strengthening behavior in seismogenic fault zones is still not fully understood also because a comprehensive database from natural fault cores is still missing. In this contribution, we present a preliminary study of seismogenic extensional fault zones in Central Apennines by combining detailed filed mapping with grain size and microstructural analysis of fault core rocks. Field mapping was aimed to describe the structural architecture of fault systems and the along-strike fault rock distribution and fracturing variations. In the laboratory we used a Malvern Mastersizer 3000 granulometer to obtain a precise grain size characterization of loose fault rocks combined with sieving for coarser size classes. In addition, we employed image analysis on thin sections to quantify the grain shape and size in cemented fault core rocks. The studied fault zones consist of an up to 5-10 m-thick fault core where most of slip is accommodated, surrounded by a tens-of-meters wide fractured damage zone. Fault core rocks consist of (1) loose to partially cemented breccias characterized by different grain size (from several cm up to mm) and variable grain shape (from very angular to sub

  1. Fault activation by hydraulic fracturing in western Canada.

    Science.gov (United States)

    Bao, Xuewei; Eaton, David W

    2016-12-16

    Hydraulic fracturing has been inferred to trigger the majority of injection-induced earthquakes in western Canada, in contrast to the Midwestern United States, where massive saltwater disposal is the dominant triggering mechanism. A template-based earthquake catalog from a seismically active Canadian shale play, combined with comprehensive injection data during a 4-month interval, shows that earthquakes are tightly clustered in space and time near hydraulic fracturing sites. The largest event [moment magnitude (MW) 3.9] occurred several weeks after injection along a fault that appears to extend from the injection zone into crystalline basement. Patterns of seismicity indicate that stress changes during operations can activate fault slip to an offset distance of >1 km, whereas pressurization by hydraulic fracturing into a fault yields episodic seismicity that can persist for months. Copyright © 2016, American Association for the Advancement of Science.

  2. Fiber Bragg Grating sensor for fault detection in radial and network transmission lines.

    Science.gov (United States)

    Moghadas, Amin A; Shadaram, Mehdi

    2010-01-01

    In this paper, a fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by Fiber Bragg Grating (FBG). The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signal. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system.

  3. Fiber Bragg Grating Sensor for Fault Detection in Radial and Network Transmission Lines

    Directory of Open Access Journals (Sweden)

    Mehdi Shadaram

    2010-10-01

    Full Text Available In this paper, a fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by Fiber Bragg Grating (FBG. The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signal. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system.

  4. A statistical-based approach for fault detection and diagnosis in a photovoltaic system

    KAUST Repository

    Garoudja, Elyes

    2017-07-10

    This paper reports a development of a statistical approach for fault detection and diagnosis in a PV system. Specifically, the overarching goal of this work is to early detect and identify faults on the DC side of a PV system (e.g., short-circuit faults; open-circuit faults; and partial shading faults). Towards this end, we apply exponentially-weighted moving average (EWMA) control chart on the residuals obtained from the one-diode model. Such a choice is motivated by the greater sensitivity of EWMA chart to incipient faults and its low-computational cost making it easy to implement in real time. Practical data from a 3.2 KWp photovoltaic plant located within an Algerian research center is used to validate the proposed approach. Results show clearly the efficiency of the developed method in monitoring PV system status.

  5. Compound faults detection in gearbox via meshing resonance and spectral kurtosis methods

    Science.gov (United States)

    Wang, Tianyang; Chu, Fulei; Han, Qinkai; Kong, Yun

    2017-03-01

    Kurtosis-based impulsive component identification is one of the most effective algorithms in detecting localized faults in both gearboxes and rolling bearings. However, if localized faults exist in both gear tooth and rolling bearing simultaneously it is difficult to tell the differences between the two types of defects. As such, this study proposes a new method to solve the problem by using the meshing resonance and spectral kurtosis (SK) algorithms together. In specific, the raw signal is first decomposed into different frequency bands and levels, and then the corresponding Kurtogram and MRgram are calculated via the fault SK analysis and the meshing index. Furthermore, the resonance frequency bands induced by localized faults of the gear tooth and rolling bearing are separately identified by comparing the Kurtogram and the MRgram. Finally, the compound faults are respectively detected using envelope analysis. The effectiveness of the proposed method has been validated via both simulated and experimental gearboxes vibration signals with compound faults.

  6. RETRACTED: Detection of active faults using EMR-Technique and Cerescope at Landau area in central Upper Rhine Graben, SW Germany

    Science.gov (United States)

    Hagag, Wael; Obermeyer, Hennes

    2016-01-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The authors have plagiarized parts of various papers notibly: The PhD thesis of Michael Krumbolz "Electromagnetic radiation as a tool to determine actual crustal stresses - applications and limitations" appearing at https://ediss.uni-goettingen.de/handle/11858/00-1735-0000-0006-B2EB-A?show=full One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. Re-use of any data should be appropriately cited. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

  7. A Novel Approach of Impulsive Signal Extraction for Early Fault Detection of Rolling Element Bearing

    Directory of Open Access Journals (Sweden)

    Hu Aijun

    2017-01-01

    Full Text Available The fault signals of rolling element bearing are often characterized by the presence of periodic impulses, which are modulated high-frequency harmonic components. The features of early fault in rolling bearing are very weak, which are often masked by background noise. The impulsiveness of the vibration signal has affected the identification of characteristic frequency for the early fault detection of the bearing. In this paper, a novel approach based on morphological operators is presented for impulsive signal extraction of early fault in rolling element bearing. The combination Top-Hat (CTH is proposed to extract the impulsive signal and enhance the impulsiveness of the bearing fault signal, and the envelope analysis is applied to reveal the fault-related signatures. The impulsive extraction performance of the proposed CTH is compared with that of finite impulse response filter (FIR by analyzing the simulated bearing fault signals, and the result indicates that the CTH is more effective in extracting impulsive signals. The method is evaluated using real fault signals from defective bearings with early rolling element fault and early fault located on the outer race. The results show that the proposed method is able to enhance the impulsiveness of early bearing fault signals.

  8. Application of a Fault Detection and Isolation System on a Rotary Machine

    Directory of Open Access Journals (Sweden)

    Silvia M. Zanoli

    2013-01-01

    Full Text Available The paper illustrates the design and the implementation of a Fault Detection and Isolation (FDI system to a rotary machine like a multishaft centrifugal compressor. A model-free approach, that is, the Principal Component Analysis (PCA, has been employed to solve the fault detection issue. For the fault isolation purpose structured residuals have been adopted while an adaptive threshold has been designed in order to detect and to isolate the faults. To prove the goodness of the proposed FDI system, historical data of a nitrogen centrifugal compressor employed in a refinery plant are considered. Tests results show that detection and isolation of single as well as multiple faults are successfully achieved.

  9. A first approach on fault detection and isolation for cardiovascular anomalies detection

    KAUST Repository

    Ledezma, Fernando

    2015-07-01

    In this paper, we use an extended version of the cardiovascular system\\'s state space model presented by [1] and propose a fault detection and isolation methodology to study the problem of detecting cardiovascular anomalies that can originate from variations in physiological parameters and deviations in the performance of the heart\\'s mitral and aortic valves. An observer-based approach is discussed as the basis of the method. The approach contemplates a bank of Extended Kalman Filters to achieve joint estimation of the model\\'s states and parameters and to detect malfunctions in the valves\\' performance. © 2015 American Automatic Control Council.

  10. Information Based Fault Diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2008-01-01

    Fault detection and isolation, (FDI) of parametric faults in dynamic systems will be considered in this paper. An active fault diagnosis (AFD) approach is applied. The fault diagnosis will be investigated with respect to different information levels from the external inputs to the systems....... These inputs are disturbance inputs, reference inputs and auxilary inputs. The diagnosis of the system is derived by an evaluation of the signature from the inputs in the residual outputs. The changes of the signatures form the external inputs are used for detection and isolation of the parametric faults....

  11. Fault detection and diagnosis for refrigerator from compressor sensor

    Science.gov (United States)

    Keres, Stephen L.; Gomes, Alberto Regio; Litch, Andrew D.

    2016-12-06

    A refrigerator, a sealed refrigerant system, and method are provided where the refrigerator includes at least a refrigerated compartment and a sealed refrigerant system including an evaporator, a compressor, a condenser, a controller, an evaporator fan, and a condenser fan. The method includes monitoring a frequency of the compressor, and identifying a fault condition in the at least one component of the refrigerant sealed system in response to the compressor frequency. The method may further comprise calculating a compressor frequency rate based upon the rate of change of the compressor frequency, wherein a fault in the condenser fan is identified if the compressor frequency rate is positive and exceeds a condenser fan fault threshold rate, and wherein a fault in the evaporator fan is identified if the compressor frequency rate is negative and exceeds an evaporator fan fault threshold rate.

  12. Reliable fault detection and diagnosis of photovoltaic systems based on statistical monitoring approaches

    KAUST Repository

    Harrou, Fouzi

    2017-09-18

    This study reports the development of an innovative fault detection and diagnosis scheme to monitor the direct current (DC) side of photovoltaic (PV) systems. Towards this end, we propose a statistical approach that exploits the advantages of one-diode model and those of the univariate and multivariate exponentially weighted moving average (EWMA) charts to better detect faults. Specifically, we generate array\\'s residuals of current, voltage and power using measured temperature and irradiance. These residuals capture the difference between the measurements and the predictions MPP for the current, voltage and power from the one-diode model, and use them as fault indicators. Then, we apply the multivariate EWMA (MEWMA) monitoring chart to the residuals to detect faults. However, a MEWMA scheme cannot identify the type of fault. Once a fault is detected in MEWMA chart, the univariate EWMA chart based on current and voltage indicators is used to identify the type of fault (e.g., short-circuit, open-circuit and shading faults). We applied this strategy to real data from the grid-connected PV system installed at the Renewable Energy Development Center, Algeria. Results show the capacity of the proposed strategy to monitors the DC side of PV systems and detects partial shading.

  13. Multiple fault detection and diagnosis in a gas turbine using nonlinear principal component analysis and structured residuals

    OpenAIRE

    Rincon-Charris, Amilcar; Quevedo Casín, Joseba Jokin

    2013-01-01

    Multiple fault detection and diagnosis is a challenging problem because the number of candidates grows exponentially in the number of faults. In add ition, multiple faults in dynamic systems may be hard to detect, because they can mask or compensate each other’s effects. This paper presents the study of the detection and diagnosis of multiple faults in a SR-30 Gas Turbine using nonlinear principal component analys is as the detection method and structured residua...

  14. Detection of arc fault based on frequency constrained independent component analysis

    Science.gov (United States)

    Yang, Kai; Zhang, Rencheng; Xu, Renhao; Chen, Yongzhi; Yang, Jianhong; Chen, Shouhong

    2015-02-01

    Arc fault is one of the main reasons of electrical fires. As a result of weakness, randomness and cross talk of arc faults, very few of methods have been successfully used to protect loads from all arc faults in low-voltage circuits. Therefore, a novel detection method is developed for detection of arc faults. The method is based on frequency constrained independent component analysis. In the process of the method derivation, a band-pass filter was introduced as a constraint condition to separate independent components of mixed signals. In the process of the independent component separations, although the fault mixed signals were under the conditions of the strong background noise and the frequency aliasing, the effective high frequency components of arc faults could be separated by frequency constrained independent component analysis. Based on the separated components, the power spectrums of them were calculated to classify the normal and the arc fault conditions. The validity of the developed method was verified by using an arc fault experimental platform set up. The results show that arc faults of nine typical electrical loads are successfully detected based on frequency constrained independent component analysis.

  15. Identification of active fault using analysis of derivatives with vertical second based on gravity anomaly data (Case study: Seulimeum fault in Sumatera fault system)

    Science.gov (United States)

    Hududillah, Teuku Hafid; Simanjuntak, Andrean V. H.; Husni, Muhammad

    2017-07-01

    Gravity is a non-destructive geophysical technique that has numerous application in engineering and environmental field like locating a fault zone. The purpose of this study is to spot the Seulimeum fault system in Iejue, Aceh Besar (Indonesia) by using a gravity technique and correlate the result with geologic map and conjointly to grasp a trend pattern of fault system. An estimation of subsurface geological structure of Seulimeum fault has been done by using gravity field anomaly data. Gravity anomaly data which used in this study is from Topex that is processed up to Free Air Correction. The step in the Next data processing is applying Bouger correction and Terrin Correction to obtain complete Bouger anomaly that is topographically dependent. Subsurface modeling is done using the Gav2DC for windows software. The result showed a low residual gravity value at a north half compared to south a part of study space that indicated a pattern of fault zone. Gravity residual was successfully correlate with the geologic map that show the existence of the Seulimeum fault in this study space. The study of earthquake records can be used for differentiating the active and non active fault elements, this gives an indication that the delineated fault elements are active.

  16. Control Surface Fault Diagnosis with Specified Detection Probability - Real Event Experiences

    DEFF Research Database (Denmark)

    Hansen, Søren; Blanke, Mogens

    2013-01-01

    desired levels of false alarms and detection probabilities. Self-tuning residual generators are employed for diagnosis and are combined with statistical change detection to form a setup for robust fault diagnosis. On-line estimation of test statistics is used to obtain a detection threshold and a desired......Diagnosis of actuator faults is crucial for aircraft since loss of actuation can have catastrophic consequences. For autonomous aircraft the steps necessary to achieve fault tolerance is limited when only basic and non-redundant sensor and actuators suites are present. Through diagnosis...... that exploits analytical redundancies it is, nevertheless, possible to cheaply enhance the level of safety. This paper presents a method for diagnosing control surface faults by using basic sensors and hardware available on an autonomous aircraft. The capability of fault diagnosis is demonstrated obtaining...

  17. Soil-gas helium and surface-waves detection of fault zones in ...

    Indian Academy of Sciences (India)

    gas helium; surface-waves; faults and fractures; groundwater; granite basement. ... Soil-gas helium emanometry has been utilized in Wailapally watershed,near Hyderabad in southern India,for the detection of fracture and fault zones in a granite ...

  18. Fault detection and diagnosis for compliance monitoring in international supply chains

    NARCIS (Netherlands)

    Wang, Yuxin; Tian, Yifu; Teixeira, André; Hulstijn, Joris; Tan, Yao-Hua

    Currently international supply chains are facing risks concerning faults in compliance, such as altering shipping documentations, fictitious inventory, and inter-company manipulations. In this paper a method to detect and diagnose fault scenarios regarding customs compliance in supply chains is

  19. Sensor fault detection and isolation over wireless sensor network based on hardware redundancy

    Science.gov (United States)

    Hao, Jingjing; Kinnaert, Michel

    2017-01-01

    In order to diagnose sensor faults with small magnitude in wireless sensor networks, distinguishability measures are defined to indicate the performance for fault detection and isolation (FDI) at each node. A systematic method is then proposed to determine the information to be exchanged between nodes to achieve FDI specifications while limiting the computation complexity and communication cost.

  20. Transient Monitoring Function–Based Fault Detection for Inverter-Interfaced Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Mehrizi-Sani, Ali

    2017-01-01

    One of the major challenges in protection of the inverter-interfaced islanded microgrids is their limited fault current level. This degrades the performance of traditional overcurrent protection schemes. This paper proposes a fault detection strategy based on monitoring the transient response of ......-domain simulation case studies using the CIGRE benchmark low voltage microgrid network....

  1. Using Order Tracking Analysis Method to Detect the Angle Faults of Blades on Wind Turbine

    DEFF Research Database (Denmark)

    Li, Pengfei; Hu, Weihao; Liu, Juncheng

    2016-01-01

    has many advantages, such as easy implementation and high system reliability. Because of using Power Spectral Density method (PSD) or Fast Fourier Transform (FFT) method cannot get clear fault characteristic frequencies, this kind of faults should be detected by an effective method. This paper...

  2. Internal leakage fault detection and tolerant control of single-rod hydraulic actuators

    National Research Council Canada - National Science Library

    Yao, Jianyong; Yang, Guichao; Ma, Dawei

    2014-01-01

    ... failures of the system components. Therefore, fault detection and diagnosis (FDD) and fault tolerant control (FTC) of hydraulic systems have received more and more attentions. FDD is a potential technique to provide efficient condition monitoring and/or preventive maintenance for hydraulic systems but is also a very challenging task, as it is extremely...

  3. Residual generation for fault detection and isolation in a class of uncertain nonlinear systems

    Science.gov (United States)

    Ma, Hong-Jun; Yang, Guang-Hong

    2013-02-01

    This article studies the problem of fault detection and isolation (FDI) for a class of uncertain nonlinear systems via a residual signal generated by a novel nonlinear adaptive observer. The considered faults are modelled by a set of time-varying vectors, in which a prescribed subset of faults are specially monitored and thus separable from the other faults. In the presence of Lipschitz-like nonlinearities and modelling uncertainties, the sensitivity of the residual signal to the monitored faults and its insensitivity to the other faults are rigorously analysed. Under a persistent excitation condition, the performances of the proposed fault diagnosis scheme, including the robustness to uncertainties, the quickness of estimation, the accuracy of estimation, the sensitivity to the monitored faults and the insensitivity to the complement faults, are quantified by a series of explicit design functions relevant to the observer parameters. It turns out that the number of faults which can be completely diagnosed is independent of the number of output sensors. A simulation example is given to illustrate the effectiveness of the proposed FDI method.

  4. In-flight Fault Detection and Isolation in Aircraft Flight Control Systems

    Science.gov (United States)

    Azam, Mohammad; Pattipati, Krishna; Allanach, Jeffrey; Poll, Scott; Patterson-Hine, Ann

    2005-01-01

    In this paper we consider the problem of test design for real-time fault detection and isolation (FDI) in the flight control system of fixed-wing aircraft. We focus on the faults that are manifested in the control surface elements (e.g., aileron, elevator, rudder and stabilizer) of an aircraft. For demonstration purposes, we restrict our focus on the faults belonging to nine basic fault classes. The diagnostic tests are performed on the features extracted from fifty monitored system parameters. The proposed tests are able to uniquely isolate each of the faults at almost all severity levels. A neural network-based flight control simulator, FLTZ(Registered TradeMark), is used for the simulation of various faults in fixed-wing aircraft flight control systems for the purpose of FDI.

  5. A Novel Online Data-Driven Algorithm for Detecting UAV Navigation Sensor Faults

    Directory of Open Access Journals (Sweden)

    Rui Sun

    2017-09-01

    Full Text Available The use of Unmanned Aerial Vehicles (UAVs has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs’ flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor fault detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS-based approach is presented for the detection of on-board navigation sensor faults in UAVs. Contrary to the classic UAV sensor fault detection algorithms, based on predefined or modelled faults, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF estimates and the ANFIS to build a reliable fault detection system. In addition, it allows fast and accurate detection of faults, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed fault detection method in terms of accuracy and misdetection rate.

  6. Compound faults detection of rotating machinery using improved adaptive redundant lifting multiwavelet

    Science.gov (United States)

    Chen, Jinglong; Zi, Yanyang; He, Zhengjia; Yuan, Jing

    2013-07-01

    Due to the character of diversity and complexity, the compound faults detection of rotating machinery under non-stationary operation turns into a challenging task. Multiwavelet with two or more base functions and many excellent properties provides a possibility to detect and extract all the features of compound faults at one time. However, the fixed basis functions independent of the vibration signal may decrease the accuracy of fault detection. Moreover, the decomposition result of discrete multiwavelet transform does not possess time invariance, which is harmful to extract the feature of periodical impulses. To overcome these deficiencies, based on the Hermite splines interpolation, taking the minimum envelope spectrum entropy as the optimization objective, adaptive redundant lifting multiwavelet is developed. Additionally, in order to eliminate error propagation of decomposition results, adaptive redundant lifting multiwavelet is improved by adding the normalization factors. As an effective method, Hilbert transform demodulation analysis is used to extract the fault feature from the high frequency modulation signal. The proposed method incorporating improved adaptive redundant lifting multiwavelet (IARLM) with Hilbert transform demodulation analysis is applied to compound faults detection for the simulation experiment, rolling element bearing test bench and traveling unit of electric locomotive. Compared with some other fault detection methods, the results show the superior effectiveness and reliability on the compound faults detection.

  7. A Novel Online Data-Driven Algorithm for Detecting UAV Navigation Sensor Faults.

    Science.gov (United States)

    Sun, Rui; Cheng, Qi; Wang, Guanyu; Ochieng, Washington Yotto

    2017-09-29

    The use of Unmanned Aerial Vehicles (UAVs) has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs' flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor fault detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS)-based approach is presented for the detection of on-board navigation sensor faults in UAVs. Contrary to the classic UAV sensor fault detection algorithms, based on predefined or modelled faults, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF) estimates and the ANFIS to build a reliable fault detection system. In addition, it allows fast and accurate detection of faults, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed fault detection method in terms of accuracy and misdetection rate.

  8. Construction and selection of lifting-based multiwavelets for mechanical fault detection

    Science.gov (United States)

    Yuan, Jing; He, Zhengjia; Zi, Yanyang; Wei, Ying

    2013-11-01

    The essence of wavelet transforms is a similar measurement between the signal and the wavelet basis functions. Thus, the construction and selection of the proper wavelet basis functions similar to the fault feature and possessing good properties such as vanishing moments have vital importance to the effective fault diagnosis. In this paper, the construction of lifting-based adaptive multiwavelets with various vanishing moments and the selection rules for different mechanical fault detection are proposed. On the basis of the fixed cubic Hermite multiwavelets, lifting schemes are adopted to construct new changeable multiwavelets with diverse vanishing moments. Then, the defined local spectral entropy minimization rules are proposed to determine the optimum multiwavelets providing the proper vanishing moments, classified into the typical shaft faults, gear faults and rolling bearing faults. The proposed method is applied to incipient fault diagnosis of rolling bearing and gearbox fault diagnosis of rolling mill to verify its effectiveness and feasibility in comparison with different wavelet transforms and spectral kurtosis. The results show that the proposed method can act as a promising tool for mechanical fault detection.

  9. A New Method for Node Fault Detection in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Peng Jiang

    2009-02-01

    Full Text Available Wireless sensor networks (WSNs are an important tool for monitoring distributed remote environments. As one of the key technologies involved in WSNs, node fault detection is indispensable in most WSN applications. It is well known that the distributed fault detection (DFD scheme checks out the failed nodes by exchanging data and mutually testing among neighbor nodes in this network., but the fault detection accuracy of a DFD scheme would decrease rapidly when the number of neighbor nodes to be diagnosed is small and the node’s failure ratio is high. In this paper, an improved DFD scheme is proposed by defining new detection criteria. Simulation results demonstrate that the improved DFD scheme performs well in the above situation and can increase the fault detection accuracy greatly.

  10. DYNAMIC SOFTWARE TESTING MODELS WITH PROBABILISTIC PARAMETERS FOR FAULT DETECTION AND ERLANG DISTRIBUTION FOR FAULT RESOLUTION DURATION

    Directory of Open Access Journals (Sweden)

    A. D. Khomonenko

    2016-07-01

    Full Text Available Subject of Research.Software reliability and test planning models are studied taking into account the probabilistic nature of error detection and discovering. Modeling of software testing enables to plan the resources and final quality at early stages of project execution. Methods. Two dynamic models of processes (strategies are suggested for software testing, using error detection probability for each software module. The Erlang distribution is used for arbitrary distribution approximation of fault resolution duration. The exponential distribution is used for approximation of fault resolution discovering. For each strategy, modified labeled graphs are built, along with differential equation systems and their numerical solutions. The latter makes it possible to compute probabilistic characteristics of the test processes and states: probability states, distribution functions for fault detection and elimination, mathematical expectations of random variables, amount of detected or fixed errors. Evaluation of Results. Probabilistic characteristics for software development projects were calculated using suggested models. The strategies have been compared by their quality indexes. Required debugging time to achieve the specified quality goals was calculated. The calculation results are used for time and resources planning for new projects. Practical Relevance. The proposed models give the possibility to use the reliability estimates for each individual module. The Erlang approximation removes restrictions on the use of arbitrary time distribution for fault resolution duration. It improves the accuracy of software test process modeling and helps to take into account the viability (power of the tests. With the use of these models we can search for ways to improve software reliability by generating tests which detect errors with the highest probability.

  11. System for detecting and limiting electrical ground faults within electrical devices

    Science.gov (United States)

    Gaubatz, Donald C.

    1990-01-01

    An electrical ground fault detection and limitation system for employment with a nuclear reactor utilizing a liquid metal coolant. Elongate electromagnetic pumps submerged within the liquid metal coolant and electrical support equipment experiencing an insulation breakdown occasion the development of electrical ground fault current. Without some form of detection and control, these currents may build to damaging power levels to expose the pump drive components to liquid metal coolant such as sodium with resultant undesirable secondary effects. Such electrical ground fault currents are detected and controlled through the employment of an isolated power input to the pumps and with the use of a ground fault control conductor providing a direct return path from the affected components to the power source. By incorporating a resistance arrangement with the ground fault control conductor, the amount of fault current permitted to flow may be regulated to the extent that the reactor may remain in operation until maintenance may be performed, notwithstanding the existence of the fault. Monitors such as synchronous demodulators may be employed to identify and evaluate fault currents for each phase of a polyphase power, and control input to the submerged pump and associated support equipment.

  12. Fault Detection and Diagnosis in Process Data Using Support Vector Machines

    Directory of Open Access Journals (Sweden)

    Fang Wu

    2014-01-01

    Full Text Available For the complex industrial process, it has become increasingly challenging to effectively diagnose complicated faults. In this paper, a combined measure of the original Support Vector Machine (SVM and Principal Component Analysis (PCA is provided to carry out the fault classification, and compare its result with what is based on SVM-RFE (Recursive Feature Elimination method. RFE is used for feature extraction, and PCA is utilized to project the original data onto a lower dimensional space. PCA T2, SPE statistics, and original SVM are proposed to detect the faults. Some common faults of the Tennessee Eastman Process (TEP are analyzed in terms of the practical system and reflections of the dataset. PCA-SVM and SVM-RFE can effectively detect and diagnose these common faults. In RFE algorithm, all variables are decreasingly ordered according to their contributions. The classification accuracy rate is improved by choosing a reasonable number of features.

  13. Slow Active Intraplate Faults: The Paleoseismology Of The Irtysh Fault Zone, Eastern Kazakhstan

    Science.gov (United States)

    Baize, S.; Reicherter, K. R.; Avagyan, A.; Belyashov, A.; Pestov, E.; Eutizio, V.; Arakelyan, A.

    2016-12-01

    The Asian plate interiors are known to host strong earthquakes with magnitudes up to M 8, especially around the border area between Mongolia, Russia, Kazakhstan and China. Their recurrence times are long, because of the low slip rates of faults smaller than 1 mm/yr. Geodynamically, our study region in eastern Kazakhstan is set in the frame of the Indian-Eurasian collision zone situated on the Eurasian craton. Major plate tectonic forces are induced by the indentation of the Indian plate into Eurasia. As a consequence, in the foreland a set of very long and large strike-slip fault zones developed, the western of which all have in common a dextral sense of shear. The more than 250 km long Irtysh Fault Zone (IFZ) marks a major tectonic block boundary separating two different units with granitoid intrusions, Silurian-Devonian magmatic rocks, and, thick deposits of Late Paleozoic age with coal measures of the Carboniferous and Permian. The formation of the IFZ probably dates back into Paleozoic times, it was repeatedly reactivated in later times. The IFZ is one potential source of large earthquakes in easternmost Kazakhstan. Tectonic-morphological analyses revealed the occurrence of a set of lineaments offsetting or deflecting streamlets and lithology. Geophysical data (GPR and seismics) helped to identify fault strands and trenching sites. Across three main segments, all longer than 50 km, a series of paleoseismic trenches was excavated. Within the trenches, faulted Holocene-Late Pleistocene deposits with organic soils, loess layers and colluvium directly overlying the Paleozoic rocks were encountered and 14C-dated. Astonishingly, no older Pleistocene rocks have been found suggesting complete erosion during/after glacial periods. Our findings lead to the conclusions that the IFZ and all segments are clearly active during the Holocene with surface ruptures displacements of around 2.0±0.2 meters, suggesting events with a magnitude around M≈7 along the individual

  14. Late Quaternary activity of the Grote Brogel fault, NE Belgium

    Science.gov (United States)

    Vanneste, Kris; Deckers, Jef; Van Noten, Koen; Schiltz, Marco; Lecocq, Thomas

    2017-04-01

    The Grote Brogel fault (GBF) is a WNW-ESE striking normal fault that is part of the western border fault system of the Roer Valley Graben in NE Belgium. It is one of three faults branching NW-ward from the main border fault (Geleen fault) near Bree, but its orientation diverges 22° from the general NW-SE orientation of the graben, causing a wide left step. Unlike the Geleen fault, the surface expression of the GBF has not been investigated in detail so far. We studied the Quaternary activity of the GBF and its effects on the local hydrology based on a high-resolution LiDAR digital terrain model (DTM), and geophysical and geological surveying at two sites, combining Electrical Resistivity Tomography (ERT), Cone Penetration Tests (CPTs) and boreholes. The GBF defines the northern edge of the Campine Plateau, an elevated area covered by the late Early to Middle Pleistocene Main Terrace of the Meuse River. Cumulative vertical offset since deposition of this terrace has resulted in a distinct 10-km-long fault scarp, the height of which decreases from 11 m near Bree in the east to less than 5 m near Grote Brogel in the west. The along-strike evolution of offset suggests that the GBF does not define an individual rupture segment, but is likely contiguous with the Geleen fault. DTM analysis indicates that scarps are only preserved in a few isolated places, and that the surface trace is rather complex, consisting of a series of short, relatively straight sections with strikes varying between 255° and 310°, arranged in a generally left-stepping pattern. At both investigated sites, ERT profiles clearly demonstrate the presence of fault splays in the shallow subsurface (< 50 m) underneath the identified scarps evidenced by a sudden increase in depth and thickness of a high-resistivity unit on top of a lower-resistivity unit. Boreholes and CPTs allow correlating the high-resistivity unit with the medium to coarse gravel-bearing sands of the Meuse Group, and the lower

  15. Fault and meal detection by redundant continuous glucose monitors and the unscented Kalman filter

    DEFF Research Database (Denmark)

    Mahmoudi, Zeinab; Nørgaard, Kirsten; Poulsen, Niels Kjølstad

    2017-01-01

    The purpose of this study is to develop a method for detecting and compensating the anomalies of continuous glucose monitoring (CGM) sensors as well as detecting unannounced meals. Both features, sensor fault detection/correction and meal detection, are necessary to have a reliable artificial...

  16. Weak fault detection and health degradation monitoring using customized standard multiwavelets

    Science.gov (United States)

    Yuan, Jing; Wang, Yu; Peng, Yizhen; Wei, Chenjun

    2017-09-01

    Due to the nonobvious symptoms contaminated by a large amount of background noise, it is challenging to beforehand detect and predictively monitor the weak faults for machinery security assurance. Multiwavelets can act as adaptive non-stationary signal processing tools, potentially viable for weak fault diagnosis. However, the signal-based multiwavelets suffer from such problems as the imperfect properties missing the crucial orthogonality, the decomposition distortion impossibly reflecting the relationships between the faults and signatures, the single objective optimization and independence for fault prognostic. Thus, customized standard multiwavelets are proposed for weak fault detection and health degradation monitoring, especially the weak fault signature quantitative identification. First, the flexible standard multiwavelets are designed using the construction method derived from scalar wavelets, seizing the desired properties for accurate detection of weak faults and avoiding the distortion issue for feature quantitative identification. Second, the multi-objective optimization combined three dimensionless indicators of the normalized energy entropy, normalized singular entropy and kurtosis index is introduced to the evaluation criterions, and benefits for selecting the potential best basis functions for weak faults without the influence of the variable working condition. Third, an ensemble health indicator fused by the kurtosis index, impulse index and clearance index of the original signal along with the normalized energy entropy and normalized singular entropy by the customized standard multiwavelets is achieved using Mahalanobis distance to continuously monitor the health condition and track the performance degradation. Finally, three experimental case studies are implemented to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed method can quantitatively identify the fault signature of a slight rub on

  17. Fault Detection and Isolation of Satellite Formations using a Ground Station Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development a fault detection and isolation (FDI) algorithm for a formation of satellites but processed at a ground station. The algorithm...

  18. Framework for the Design and Implementation of Fault Detection and Isolation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SySense, Inc. proposes to develop a framework for the design and implementation of fault detection and isolation (FDI) systems. The framework will include protocols...

  19. Automatic Supervision And Fault Detection In PV System By Wireless Sensors With Interfacing By Labview Program

    Directory of Open Access Journals (Sweden)

    Yousra M Abbas

    2015-08-01

    Full Text Available In this work a wireless monitoring system are designed for automatic detection localization fault in photovoltaic system. In order to avoid the use of modeling and simulation of the PV system we detected the fault by monitoring the output of each individual photovoltaic panel connected in the system by Arduino and transmit this data wirelessly to laptop then interface it by LabVIEW program which made comparison between this data and the measured data taking from reference module at the same condition. The proposed method is very simple but effective detecting and diagnosing the main faults of a PV system and was experimentally validated and has demonstrated its effectiveness in the detection and diagnosing of main faults present in the DC side of PV system.

  20. Detection of Partial Demagnetization Fault in PMSMs Operating under Nonstationary Conditions

    DEFF Research Database (Denmark)

    Wang, Chao; Delgado Prieto, Miguel; Romeral, Luis

    2016-01-01

    Demagnetization fault detection of in-service Permanent Magnet Synchronous Machines (PMSMs) is a challenging task because most PMSMs operate under nonstationary circumstances in industrial applications. A novel approach based on tracking characteristic orders of stator current using Vold...

  1. An Approach on Fault Detection in Diesel Engine by Using Symmetrical Polar Coordinates and Image Recognition

    Directory of Open Access Journals (Sweden)

    Ruili Zeng

    2014-07-01

    Full Text Available Vibration technique provides useful information in fault detection of diesel engine, bringing significant cost benefits to diesel engine condition monitoring. Usually, time-frequency calculation on vibration signal is so complex that it is difficult to achieve online fault detection. In this paper, a method of fault detection in diesel engine is developed based on symmetrical polar coordinates and image recognition. In this method, time-domain waveform of vibration signal is transformed into snowflake-shaped in mirror symmetry pattern without time-frequency analysis. By the comparison of the geometric features of the snowflake images from different wear conditions of crankshaft bearing in diesel engines, we use centroid position and direction angle of the petal in snowflake image as features to detect the fault. Then, fuzzy c-means (FCM are used to detect the conditions of the engine according to these features. In order to validate the methods, some experiments have been performed, the experimental results show that the centroid position and direction angle of the petal in snowflake image can reflect the information of different wear conditions in crankshaft bearing, and the fault of crankshaft bearing can be detected accurately. Hence, the method can work as fault detection in diesel engine, which is simple and effective, compared with time-frequency calculation method.

  2. A Kalman Filter Based Technique for Stator Turn-Fault Detection of the Induction Motors

    Science.gov (United States)

    Ghanbari, Teymoor; Samet, Haidar

    2017-11-01

    Monitoring of the Induction Motors (IMs) through stator current for different faults diagnosis has considerable economic and technical advantages in comparison with the other techniques in this content. Among different faults of an IM, stator and bearing faults are more probable types, which can be detected by analyzing signatures of the stator currents. One of the most reliable indicators for fault detection of IMs is lower sidebands of power frequency in the stator currents. This paper deals with a novel simple technique for detecting stator turn-fault of the IMs. Frequencies of the lower sidebands are determined using the motor specifications and their amplitudes are estimated by a Kalman Filter (KF). Instantaneous Total Harmonic Distortion (ITHD) of these harmonics is calculated. Since variation of the ITHD for the three-phase currents is considerable in case of stator turn-fault, the fault can be detected using this criterion, confidently. Different simulation results verify high performance of the proposed method. The performance of the method is also confirmed using some experiments.

  3. Detection of stator winding faults in induction machines using flux and vibration analysis

    Science.gov (United States)

    Lamim Filho, P. C. M.; Pederiva, R.; Brito, J. N.

    2014-01-01

    This work aims at presenting the detection and diagnosis of electrical faults in the stator winding of three-phase induction motors using magnetic flux and vibration analysis techniques. A relationship was established between the main electrical faults (inter-turn short circuits and unbalanced voltage supplies) and the signals of magnetic flux and vibration, in order to identify the characteristic frequencies of those faults. The experimental results showed the efficiency of the conjugation of these techniques for detection, diagnosis and monitoring tasks. The results were undoubtedly impressive and can be adapted and used in real predictive maintenance programs in industries.

  4. Observer and data-driven model based fault detection in Power Plant Coal Mills

    DEFF Research Database (Denmark)

    Fogh Odgaard, Peter; Lin, Bao; Jørgensen, Sten Bay

    2008-01-01

    model with motor power as the controlled variable, data-driven methods for fault detection are also investigated. Regression models that represent normal operating conditions (NOCs) are developed with both static and dynamic principal component analysis and partial least squares methods. The residual...... between process measurement and the NOC model prediction is used for fault detection. A hybrid approach, where a data-driven model is employed to derive an optimal unknown input observer, is also implemented. The three methods are evaluated with case studies on coal mill data, which includes a fault...

  5. Fault Detection for Shipboard Monitoring – Volterra Kernel and Hammerstein Model Approaches

    DEFF Research Database (Denmark)

    Lajic, Zoran; Blanke, Mogens; Nielsen, Ulrik Dam

    2009-01-01

    In this paper nonlinear fault detection for in-service monitoring and decision support systems for ships will be presented. The ship is described as a nonlinear system, and the stochastic wave elevation and the associated ship responses are conveniently modelled in frequency domain....... The transformation from time domain to frequency domain has been conducted by use of Volterra theory. The paper takes as an example fault detection of a containership on which a decision support system has been installed....

  6. Fused Empirical Mode Decomposition and MUSIC Algorithms for Detecting Multiple Combined Faults in Induction Motors

    Directory of Open Access Journals (Sweden)

    D. Camarena-Martinez

    2015-02-01

    Full Text Available Detection of failures in induction motors is one of the most important concerns in industry. An unexpected fault in the induction motors can cause a loss of financial resources and waste of time that most companies cannot afford. The contribution of this paper is a fusion of the Empirical Mode Decomposition (EMD and Multiple Signal Classification (MUSIC methodologies for detection of multiple combined faults which provides an accurate and effective strategy for the motor condition diagnosis.

  7. Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids

    OpenAIRE

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong

    2017-01-01

    Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility m...

  8. Autonomous Fault Detection for Performance Bugs in Component Based Robotic Systems

    Science.gov (United States)

    2016-12-01

    requiring a manual modeling of the system behavior . 3295 Khalastchi et al. [11], in contrast, introduce an online fault detection approach which is purely...diagnosis of robot navigation software,” in Simulation, Modeling , and Programming for Autonomous Robots, S. Carpin, I. Noda, E. Pagello, M. Reggiani, and... Autonomous Fault Detection for Performance Bugs in Component-Based Robotic Systems Johannes Wienke1 and Sebastian Wrede1 Abstract— We present a novel

  9. Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain

    Science.gov (United States)

    2014-01-01

    Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain by Kelsen E. LaBerge, Eric C. Ames, and Brian D. Dykas...5066 ARL-TR-6795 January 2014 Detection of Naturally Occurring Gear and Bearing Faults in a Helicopter Drivetrain Kelsen E. LaBerge...ELEMENT NUMBER 6. AUTHOR(S) Kelsen E. LaBerge, Eric C. Ames, and Brian D. Dykas 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER

  10. Earthquake Probability Assessment for the Active Faults in Central Taiwan: A Case Study

    Directory of Open Access Journals (Sweden)

    Yi-Rui Lee

    2016-06-01

    Full Text Available Frequent high seismic activities occur in Taiwan due to fast plate motions. According to the historical records the most destructive earthquakes in Taiwan were caused mainly by inland active faults. The Central Geological Survey (CGS of Taiwan has published active fault maps in Taiwan since 1998. There are 33 active faults noted in the 2012 active fault map. After the Chi-Chi earthquake, CGS launched a series of projects to investigate the details to better understand each active fault in Taiwan. This article collected this data to develop active fault parameters and referred to certain experiences from Japan and the United States to establish a methodology for earthquake probability assessment via active faults. We consider the active faults in Central Taiwan as a good example to present the earthquake probability assessment process and results. The appropriate “probability model” was used to estimate the conditional probability where M ≥ 6.5 and M ≥ 7.0 earthquakes. Our result shows that the highest earthquake probability for M ≥ 6.5 earthquake occurring in 30, 50, and 100 years in Central Taiwan is the Tachia-Changhua fault system. Conversely, the lowest earthquake probability is the Chelungpu fault. The goal of our research is to calculate the earthquake probability of the 33 active faults in Taiwan. The active fault parameters are important information that can be applied in the following seismic hazard analysis and seismic simulation.

  11. An Active Fault-Tolerant Control Method Ofunmanned Underwater Vehicles with Continuous and Uncertain Faults

    Directory of Open Access Journals (Sweden)

    Daqi Zhu

    2008-11-01

    Full Text Available This paper introduces a novel thruster fault diagnosis and accommodation system for open-frame underwater vehicles with abrupt faults. The proposed system consists of two subsystems: a fault diagnosis subsystem and a fault accommodation sub-system. In the fault diagnosis subsystem a ICMAC(Improved Credit Assignment Cerebellar Model Articulation Controllers neural network is used to realize the on-line fault identification and the weighting matrix computation. The fault accommodation subsystem uses a control algorithm based on weighted pseudo-inverse to find the solution of the control allocation problem. To illustrate the proposed method effective, simulation example, under multi-uncertain abrupt faults, is given in the paper.

  12. Detection and Quantization of Bearing Fault in Direct Drive Wind Turbine via Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Wei Teng

    2016-01-01

    Full Text Available Bearing fault is usually buried by intensive noise because of the low speed and heavy load in direct drive wind turbine (DDWT. Furthermore, varying wind speed and alternating loads make it difficult to quantize bearing fault feature that indicates the degree of deterioration. This paper presents the application of multiscale enveloping spectrogram (MuSEnS and cepstrum to detect and quantize bearing fault in DDWT. MuSEnS can manifest fault modulation information adaptively based on the capacity of complex wavelet transform, which enables the weak bearing fault in DDWT to be detected. Cepstrum can calculate the average interval of periodic components in frequency domain and is suitable for quantizing bearing fault feature under varying operation conditions due to the logarithm weight on the power spectrum. Through comparing a faulty DDWT with a normal one, the bearing fault feature is evidenced and the quantization index is calculated, which show a good application prospect for condition monitoring and fault diagnosis in real DDWT.

  13. Methods and apparatus using commutative error detection values for fault isolation in multiple node computers

    Science.gov (United States)

    Almasi, Gheorghe [Ardsley, NY; Blumrich, Matthias Augustin [Ridgefield, CT; Chen, Dong [Croton-On-Hudson, NY; Coteus, Paul [Yorktown, NY; Gara, Alan [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Hoenicke, Dirk I [Ossining, NY; Singh, Sarabjeet [Mississauga, CA; Steinmacher-Burow, Burkhard D [Wernau, DE; Takken, Todd [Brewster, NY; Vranas, Pavlos [Bedford Hills, NY

    2008-06-03

    Methods and apparatus perform fault isolation in multiple node computing systems using commutative error detection values for--example, checksums--to identify and to isolate faulty nodes. When information associated with a reproducible portion of a computer program is injected into a network by a node, a commutative error detection value is calculated. At intervals, node fault detection apparatus associated with the multiple node computer system retrieve commutative error detection values associated with the node and stores them in memory. When the computer program is executed again by the multiple node computer system, new commutative error detection values are created and stored in memory. The node fault detection apparatus identifies faulty nodes by comparing commutative error detection values associated with reproducible portions of the application program generated by a particular node from different runs of the application program. Differences in values indicate a possible faulty node.

  14. Enhanced Fault Detection of Rolling Element Bearing Based on Cepstrum Editing and Stochastic Resonance

    Science.gov (United States)

    Zhang, Xiaofei; Hu, Niaoqing; Hu, Lei; Fan, Bin; Cheng, Zhe

    2012-05-01

    By signal pre-whitening based on cepstrum editing,the envelope analysis can be done over the full bandwidth of the pre-whitened signal, and this enhances the bearing characteristic frequencies. The bearing faults detection could be enhanced without knowledge of the optimum frequency bands to demodulate, however, envelope analysis over full bandwidth brings more noise interference. Stochastic resonance (SR), which is now often used in weak signal detection, is an important nonlinear effect. By normalized scale transform, SR can be applied in weak signal detection of machinery system. In this paper, signal pre-whitening based on cepstrum editing and SR theory are combined to enhance the detection of bearing fault. The envelope spectrum kurtosis of bearing fault characteristic components is used as indicators of bearing faults. Detection results of planted bearing inner race faults on a test rig show the enhanced detecting effects of the proposed method. And the indicators of bearing inner race faults enhanced by SR are compared to the ones without enhancement to validate the proposed method.

  15. Patterns of fault interactions triggered by micro earthquake activity

    OpenAIRE

    V. Mouslopoulou; D. Hristopulos

    2010-01-01

    Historical earthquakes are often strongly clustered in space and time. This clustering has been attributed to static stress triggering associated with tectonic fault interactions and/or fluid migration. Discrimination between these two models requires detailed information on the timing, location and size of earthquakes. The Matata earthquake sequence, which occurred within the active Taupo Rift in New Zealand, provides a unique opportunity to chart spatial and temporal patterns of earthquakes...

  16. Fault Detection of Aircraft Cable via Spread Spectrum Time Domain Reflectometry

    Directory of Open Access Journals (Sweden)

    Xudong SHI

    2014-03-01

    Full Text Available As the airplane cable fault detection based on TDR (time domain reflectometry is affected easily by various noise signals, which makes the reflected signal attenuate and distort heavily, failing to locate the fault. In order to solve these problems, a method of spread spectrum time domain reflectometry (SSTDR is introduced in this paper, taking the advantage of the sharp peak of correlation function. The test signal is generated from ML sequence (MLS modulated by sine wave in the same frequency. Theoretically, the test signal has the very high immunity of noise, which can be applied with excellent precision to fault location on the aircraft cable. In this paper, the method of SSTDR was normally simulated in MATLAB. Then, an experimental setup, based on LabVIEW, was organized to detect and locate the fault on the aircraft cable. It has been demonstrated that SSTDR has the high immunity of noise, reducing some detection errors effectively.

  17. Fault detection and classification in electrical power transmission system using artificial neural network.

    Science.gov (United States)

    Jamil, Majid; Sharma, Sanjeev Kumar; Singh, Rajveer

    2015-01-01

    This paper focuses on the detection and classification of the faults on electrical power transmission line using artificial neural networks. The three phase currents and voltages of one end are taken as inputs in the proposed scheme. The feed forward neural network along with back propagation algorithm has been employed for detection and classification of the fault for analysis of each of the three phases involved in the process. A detailed analysis with varying number of hidden layers has been performed to validate the choice of the neural network. The simulation results concluded that the present method based on the neural network is efficient in detecting and classifying the faults on transmission lines with satisfactory performances. The different faults are simulated with different parameters to check the versatility of the method. The proposed method can be extended to the Distribution network of the Power System. The various simulations and analysis of signals is done in the MATLAB(®) environment.

  18. FAULT DETECTION AND DIAGNOSIS ON A PWM INVERTER BY DIFFERENT TECHNIQUES

    Directory of Open Access Journals (Sweden)

    S. Chafei

    2008-06-01

    Full Text Available This paper investigates the use of different techniques for fault detection in voltage-fed asynchronous machine drive systems. With the proposed techniques it is possible to detect and identify the power switch in which the fault has occurred. A diagnosis system which uses only the input variables of the drive is presented. It is based on the analysis of the current-vector trajectory, of the instantaneous frequency in faulty mode, and the evaluation of machine state variables which are processed due to the machine control algorithm. With this algorithm a fast an reliable fault detection can be realized. Furthermore limited drive operation in case of a fault mode will be discussed. All obtained results are based on computer simulation. These knowledge based methods have been test in simulation.

  19. Fault detection and diagnosis in nonlinear systems a differential and algebraic viewpoint

    CERN Document Server

    Martinez-Guerra, Rafael

    2014-01-01

    The high reliability required in industrial processes has created the necessity of detecting abnormal conditions, called faults, while processes are operating. The term fault generically refers to any type of process degradation, or degradation in equipment performance because of changes in the process's physical characteristics, process inputs or environmental conditions. This book is about the fundamentals of fault detection and diagnosis in a variety of nonlinear systems which are represented by ordinary differential equations. The fault detection problem is approached from a differential algebraic viewpoint, using residual generators based upon high-gain nonlinear auxiliary systems (‘observers’). A prominent role is played by the type of mathematical tools that will be used, requiring knowledge of differential algebra and differential equations. Specific theorems tailored to the needs of the problem-solving procedures are developed and proved. Applications to real-world problems, both with constant an...

  20. Fault detection, isolation, and diagnosis of self-validating multifunctional sensors.

    Science.gov (United States)

    Yang, Jing-Li; Chen, Yin-Sheng; Zhang, Li-Li; Sun, Zhen

    2016-06-01

    A novel fault detection, isolation, and diagnosis (FDID) strategy for self-validating multifunctional sensors is presented in this paper. The sparse non-negative matrix factorization-based method can effectively detect faults by using the squared prediction error (SPE) statistic, and the variables contribution plots based on SPE statistic can help to locate and isolate the faulty sensitive units. The complete ensemble empirical mode decomposition is employed to decompose the fault signals to a series of intrinsic mode functions (IMFs) and a residual. The sample entropy (SampEn)-weighted energy values of each IMFs and the residual are estimated to represent the characteristics of the fault signals. Multi-class support vector machine is introduced to identify the fault mode with the purpose of diagnosing status of the faulty sensitive units. The performance of the proposed strategy is compared with other fault detection strategies such as principal component analysis, independent component analysis, and fault diagnosis strategies such as empirical mode decomposition coupled with support vector machine. The proposed strategy is fully evaluated in a real self-validating multifunctional sensors experimental system, and the experimental results demonstrate that the proposed strategy provides an excellent solution to the FDID research topic of self-validating multifunctional sensors.

  1. Improved Sensor Fault Detection, Isolation, and Mitigation Using Multiple Observers Approach.

    Science.gov (United States)

    Wang, Zheng; Anand, D M; Moyne, J; Tilbury, D M

    2017-01-01

    Traditional Fault Detection and Isolation (FDI) methods analyze a residual signal to detect and isolate sensor faults. The residual signal is the difference between the sensor measurements and the estimated outputs of the system based on an observer. The traditional residual-based FDI methods, however, have some limitations. First, they require that the observer has reached its steady state. In addition, residual-based methods may not detect some sensor faults, such as faults on critical sensors that result in an unobservable system. Furthermore, the system may be in jeopardy if actions required for mitigating the impact of the faulty sensors are not taken before the faulty sensors are identified. The contribution of this paper is to propose three new methods to address these limitations. Faults that occur during the observers' transient state can be detected by analyzing the convergence rate of the estimation error. Open-loop observers, which do not rely on sensor information, are used to detect faults on critical sensors. By switching among different observers, we can potentially mitigate the impact of the faulty sensor during the FDI process. These three methods are systematically integrated with a previously developed residual-based method to provide an improved FDI and mitigation capability framework. The overall approach is validated mathematically, and the effectiveness of the overall approach is demonstrated through simulation on a 5-state suspension system.

  2. Optimal Threshold Functions for Fault Detection and Isolation

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.; Harbo, Anders La-Cour

    2003-01-01

    Fault diagnosis systems usually comprises two parts: a filtering part and a decision part, the latter typically based on threshold functions. In this paper, systematic ways to choose the threshold values are proposed. Two different test functions for the filtered signals are discussed and a method...

  3. Detecting intermittent resistive faults in digital CMOS circuits

    NARCIS (Netherlands)

    Ebrahimi, Hassan; Kerkhoff, Hans G.; Rohani, A.

    2016-01-01

    Interconnection reliability threats dependability of highly critical electronic systems. One of most challenging interconnection-induced reliability threats are intermittent resistive faults (IRFs). The occurrence rate of this kind of defects can take e.g. one month, and the duration of defects can

  4. Similarity ratio analysis for early stage fault detection with optical emission spectrometer in plasma etching process.

    Directory of Open Access Journals (Sweden)

    Jie Yang

    Full Text Available A Similarity Ratio Analysis (SRA method is proposed for early-stage Fault Detection (FD in plasma etching processes using real-time Optical Emission Spectrometer (OES data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch-rate faults in real-time during an etching process. The method processes spectrum scans at successive time points and uses a windowing mechanism over the time series to alleviate problems with timing uncertainties due to process shift from one process run to another. A SRA library is first built to capture features of a healthy etching process. By comparing with the SRA library, a Similarity Ratio (SR statistic is then calculated for each spectrum scan as the monitored process progresses. A fault detection mechanism, named 3-Warning-1-Alarm (3W1A, takes the SR values as inputs and triggers a system alarm when certain conditions are satisfied. This design reduces the chance of false alarm, and provides a reliable fault reporting service. The SRA method is demonstrated on a real semiconductor manufacturing dataset. The effectiveness of SRA-based fault detection is evaluated using a time-series SR test and also using a post-process SR test. The time-series SR provides an early-stage fault detection service, so less energy and materials will be wasted by faulty processing. The post-process SR provides a fault detection service with higher reliability than the time-series SR, but with fault testing conducted only after each process run completes.

  5. Enhanced detection of rolling element bearing fault based on stochastic resonance

    Science.gov (United States)

    Zhang, Xiaofei; Hu, Niaoqing; Cheng, Zhe; Hu, Lei

    2012-11-01

    Early bearing faults can generate a series of weak impacts. All the influence factors in measurement may degrade the vibration signal. Currently, bearing fault enhanced detection method based on stochastic resonance(SR) is implemented by expensive computation and demands high sampling rate, which requires high quality software and hardware for fault diagnosis. In order to extract bearing characteristic frequencies component, SR normalized scale transform procedures are presented and a circuit module is designed based on parameter-tuning bistable SR. In the simulation test, discrete and analog sinusoidal signals under heavy noise are enhanced by SR normalized scale transform and circuit module respectively. Two bearing fault enhanced detection strategies are proposed. One is realized by pure computation with normalized scale transform for sampled vibration signal, and the other is carried out by designed SR hardware with circuit module for analog vibration signal directly. The first strategy is flexible for discrete signal processing, and the second strategy demands much lower sampling frequency and less computational cost. The application results of the two strategies on bearing inner race fault detection of a test rig show that the local signal to noise ratio of the characteristic components obtained by the proposed methods are enhanced by about 50% compared with the band pass envelope analysis for the bearing with weaker fault. In addition, helicopter transmission bearing fault detection validates the effectiveness of the enhanced detection strategy with hardware. The combination of SR normalized scale transform and circuit module can meet the need of different application fields or conditions, thus providing a practical scheme for enhanced detection of bearing fault.

  6. Robust Fault-Tolerant Control for Satellite Attitude Stabilization Based on Active Disturbance Rejection Approach with Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Fei Song

    2014-01-01

    Full Text Available This paper proposed a robust fault-tolerant control algorithm for satellite stabilization based on active disturbance rejection approach with artificial bee colony algorithm. The actuating mechanism of attitude control system consists of three working reaction flywheels and one spare reaction flywheel. The speed measurement of reaction flywheel is adopted for fault detection. If any reaction flywheel fault is detected, the corresponding fault flywheel is isolated and the spare reaction flywheel is activated to counteract the fault effect and ensure that the satellite is working safely and reliably. The active disturbance rejection approach is employed to design the controller, which handles input information with tracking differentiator, estimates system uncertainties with extended state observer, and generates control variables by state feedback and compensation. The designed active disturbance rejection controller is robust to both internal dynamics and external disturbances. The bandwidth parameter of extended state observer is optimized by the artificial bee colony algorithm so as to improve the performance of attitude control system. A series of simulation experiment results demonstrate the performance superiorities of the proposed robust fault-tolerant control algorithm.

  7. A universal, fault-tolerant, non-linear analytic network for modeling and fault detection

    Energy Technology Data Exchange (ETDEWEB)

    Mott, J.E. [Advanced Modeling Techniques Corp., Idaho Falls, ID (United States); King, R.W.; Monson, L.R.; Olson, D.L.; Staffon, J.D. [Argonne National Lab., Idaho Falls, ID (United States)

    1992-03-06

    The similarities and differences of a universal network to normal neural networks are outlined. The description and application of a universal network is discussed by showing how a simple linear system is modeled by normal techniques and by universal network techniques. A full implementation of the universal network as universal process modeling software on a dedicated computer system at EBR-II is described and example results are presented. It is concluded that the universal network provides different feature recognition capabilities than a neural network and that the universal network can provide extremely fast, accurate, and fault-tolerant estimation, validation, and replacement of signals in a real system.

  8. Fault Diagnosis and Detection in Industrial Motor Network Environment Using Knowledge-Level Modelling Technique

    Directory of Open Access Journals (Sweden)

    Saud Altaf

    2017-01-01

    Full Text Available In this paper, broken rotor bar (BRB fault is investigated by utilizing the Motor Current Signature Analysis (MCSA method. In industrial environment, induction motor is very symmetrical, and it may have obvious electrical signal components at different fault frequencies due to their manufacturing errors, inappropriate motor installation, and other influencing factors. The misalignment experiments revealed that improper motor installation could lead to an unexpected frequency peak, which will affect the motor fault diagnosis process. Furthermore, manufacturing and operating noisy environment could also disturb the motor fault diagnosis process. This paper presents efficient supervised Artificial Neural Network (ANN learning technique that is able to identify fault type when situation of diagnosis is uncertain. Significant features are taken out from the electric current which are based on the different frequency points and associated amplitude values with fault type. The simulation results showed that the proposed technique was able to diagnose the target fault type. The ANN architecture worked well with selecting of significant number of feature data sets. It seemed that, to the results, accuracy in fault detection with features vector has been achieved through classification performance and confusion error percentage is acceptable between healthy and faulty condition of motor.

  9. Active faults and related Late Quaternary deformation along the Northwestern Himalayan Frontal Zone, India

    Directory of Open Access Journals (Sweden)

    T. Nakata

    2003-06-01

    Full Text Available Numerous newly-identified traces of active faults in the Himalayan foothill zone along the HFF around Chandigarh, in Pinjore Dun, along the piedmont zone of the Lower Siwalik hill front and within the Lower Tertiary hill range reveal the pattern of thrust and strike-slip faulting, striking parallel to the principal structural trend (NNW-SSE of the orogenic belt. The active Chandigarh Fault, Pinjore Garden Fault and Barsar thrust have vertically dislocated, warped and backtilted fluvial and alluvial-fan surfaces made up of Late Pleistocene-Holocene sediments. West- and southwest-facing fault scarplets with heights ranging from 12 to 50 m along these faults suggest continued tectonic movement through Late Pleistocene to recent times. Gentle warping and backtilting of the terraces on the hanging wall sides of the faults indicate fault-bend folding. These active faults are the manifestation of north-dipping imbricated thrust faults branching out from the major fault systems like the Main Boundary Fault (MBF and Himalayan Frontal Fault (HFF, probably merging down northward into a décollement. The Taksal Fault, striking NNW-SSE, shows prominent right-lateral movement marked by lateral offset of streams and younger Quaternary terraces and occupies a narrow deep linear valley along the fault trace. Right stepping along this fault has resulted in formation of a small pull-apart basin. Fault scarplets facing ENE and WSW are the manifestation of dip-slip movement. This fault is an example of slip-partitioning between the strike-slip and thrust faults, suggesting ongoing oblique convergence of the Indian plate and northward migration of a tectonic sliver. Slip rate along the Taksal Fault has been calculated as 2.8 mm/yr. Preliminary trench investigation at the base of the Chandigarh Fault Scarp has revealed total displacement of 3.5 m along a low angle thrust fault with variable dip of 20° to 46° due northeast, possibly the result of one

  10. Gear-box fault detection using time-frequency based methods

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2015-01-01

    Gear-box fault monitoring and detection is important for optimization of power generation and availability of wind turbines. The current industrial approach is to use condition monitoring systems, which runs in parallel with the wind turbine control system, using expensive additional sensors...... in the gear-box resonance frequency can be detected. Two different time–frequency based approaches are presented in this paper. One is a filter based approach and the other is based on a Karhunen–Loeve basis. Both of them detect the gear-box fault with an acceptable detection delay of maximum 100s, which...

  11. Fault Detection based on MCSA for a 400Hz Asynchronous Motor for Airborne Applications

    Directory of Open Access Journals (Sweden)

    Steffen Haus

    2013-01-01

    Full Text Available Future health monitoring concepts in different fields of engineering require reliable fault detection to avoid unscheduled machine downtime. Diagnosis of electrical induction machines for industrial applications is widely discussed in literature. In aviation industry, this topic is still only rarely discussed.A common approach to health monitoring for electrical induction machines is to use Motor Current Signature Analysis (MCSA based on a Fast Fourier Transform (FFT. Research results on this topic are available for comparatively large motors, where the power supply is typically based on 50Hz alternating current, which is the general power supply frequency for industrial applications.In this paper, transferability to airborne applications, where the power supply is 400Hz, is assessed. Three phase asynchronous motors are used to analyse detectability of different motor faults. The possibility to transfer fault detection results from 50Hz to 400Hz induction machines is the main question answered in this research work. 400Hz power supply frequency requires adjusted motor design, causing increased motor speed compared to 50Hz supply frequency. The motor used for experiments in this work is a 800W motor with 200V phase to phase power supply, powering an avionic fan. The fault cases to be examined are a bearing fault, a rotor unbalance, a stator winding fault, a broken rotor bar and a static air gap eccentricity. These are the most common faults in electrical induction machines which can cause machine downtime. The focus of the research work is the feasibility of the application of MCSA for small scale, high speed motor design, using the Fourier spectra of the current signal.Detectability is given for all but the bearing fault, although rotor unbalance can only be detected in case of severe damage level. Results obtained in the experiments are interpreted with respect to the motor design. Physical interpretation are given in case the results differ

  12. A geometric approach for fault detection and isolation of stator short circuit failure in a single asynchronous machine

    KAUST Repository

    Khelouat, Samir

    2012-06-01

    This paper deals with the problem of detection and isolation of stator short-circuit failure in a single asynchronous machine using a geometric approach. After recalling the basis of the geometric approach for fault detection and isolation in nonlinear systems, we will study some structural properties which are fault detectability and isolation fault filter existence. We will then design filters for residual generation. We will consider two approaches: a two-filters structure and a single filter structure, both aiming at generating residuals which are sensitive to one fault and insensitive to the other faults. Some numerical tests will be presented to illustrate the efficiency of the method.

  13. Robust Fault Detection of Wind Energy Conversion Systems Based on Dynamic Neural Networks

    Directory of Open Access Journals (Sweden)

    Nasser Talebi

    2014-01-01

    Full Text Available Occurrence of faults in wind energy conversion systems (WECSs is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS is required. Recurrent neural networks (RNNs have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate.

  14. Robust fault detection of wind energy conversion systems based on dynamic neural networks.

    Science.gov (United States)

    Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

    2014-01-01

    Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate.

  15. Methodology for fault detection in induction motors via sound and vibration signals

    Science.gov (United States)

    Delgado-Arredondo, Paulo Antonio; Morinigo-Sotelo, Daniel; Osornio-Rios, Roque Alfredo; Avina-Cervantes, Juan Gabriel; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene de Jesus

    2017-01-01

    Nowadays, timely maintenance of electric motors is vital to keep up the complex processes of industrial production. There are currently a variety of methodologies for fault diagnosis. Usually, the diagnosis is performed by analyzing current signals at a steady-state motor operation or during a start-up transient. This method is known as motor current signature analysis, which identifies frequencies associated with faults in the frequency domain or by the time-frequency decomposition of the current signals. Fault identification may also be possible by analyzing acoustic sound and vibration signals, which is useful because sometimes this information is the only available. The contribution of this work is a methodology for detecting faults in induction motors in steady-state operation based on the analysis of acoustic sound and vibration signals. This proposed approach uses the Complete Ensemble Empirical Mode Decomposition for decomposing the signal into several intrinsic mode functions. Subsequently, the frequency marginal of the Gabor representation is calculated to obtain the spectral content of the IMF in the frequency domain. This proposal provides good fault detectability results compared to other published works in addition to the identification of more frequencies associated with the faults. The faults diagnosed in this work are two broken rotor bars, mechanical unbalance and bearing defects.

  16. Detection of Inter-turn Faults in Five-Phase Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    SAAVEDRA, H.

    2014-11-01

    Full Text Available Five-phase permanent magnet synchronous motors (PMSMs have inherent fault-tolerant capabilities. This paper analyzes the detection of inter-turn short circuit faults in five-phase PMSMs in their early stage, i.e. with only one turn in short circuit by means of the analysis of the stator currents and the zero-sequence voltage component (ZSVC spectra. For this purpose, a parametric model of five-phase PMSMs which accounts for the effects of inter-turn short circuits is developed to determine the most suitable harmonic frequencies to be analyzed to detect such faults. The amplitudes of these fault harmonic are analyzed in detail by means of finite-elements method (FEM simulations, which corroborate the predictions of the parametric model. A low-speed five-phase PMSM for in-wheel applications is studied and modeled. This paper shows that the ZSVC-based method provides better sensitivity to diagnose inter-turn faults in the analyzed low-speed application. Results presented under a wide speed range and different load levels show that it is feasible to diagnose such faults in their early stage, thus allowing applying a post-fault strategy to minimize their effects while ensuring a safe operation.

  17. Avionic Air Data Sensors Fault Detection and Isolation by means of Singular Perturbation and Geometric Approach.

    Science.gov (United States)

    Castaldi, Paolo; Mimmo, Nicola; Simani, Silvio

    2017-09-25

    Singular Perturbations represent an advantageous theory to deal with systems characterized by a two-time scale separation, such as the longitudinal dynamics of aircraft which are called phugoid and short period. In this work, the combination of the NonLinear Geometric Approach and the Singular Perturbations leads to an innovative Fault Detection and Isolation system dedicated to the isolation of faults affecting the air data system of a general aviation aircraft. The isolation capabilities, obtained by means of the approach proposed in this work, allow for the solution of a fault isolation problem otherwise not solvable by means of standard geometric techniques. Extensive Monte-Carlo simulations, exploiting a high fidelity aircraft simulator, show the effectiveness of the proposed Fault Detection and Isolation system.

  18. Fault kinematics and active tectonics at the southeastern boundary of the eastern Alborz (Abr and Khij fault zones): geodynamic implications for NNE Iran

    OpenAIRE

    Javidfakhr, Bita; Bellier, Olivier; Shabanian, Esmaeil; Siame, Lionel; Léanni, Laëtitia; Bourlès, Didier; Ahmadian, Seiran

    2011-01-01

    Abstract The Alborz is a region of active deformation within the Arabia-Eurasia collision zone. The Abr and the Khij Faults are two NE-trending left-lateral strike-slip faults in the eastern Alborz that correspond to the Shahrud fault system extended through an area of about 95?55 km2. Tectonic landforms typically associated with active strike-slip faults, such as deflected stream channels, offset ridges and fault scarps are documented along the mentioned faults. Detailed analyses ...

  19. A Framework and Classification for Fault Detection Approaches in Wireless Sensor Networks with an Energy Efficiency Perspective

    DEFF Research Database (Denmark)

    Zhang, Yue; Dragoni, Nicola; Wang, Jiangtao

    2015-01-01

    Wireless Sensor Networks (WSNs) are more and more considered a key enabling technology for the realisation of the Internet of Things (IoT) vision. With the long term goal of designing fault-tolerant IoT systems, this paper proposes a fault detection framework for WSNs with the perspective of energy...... approaches for the comparison of several characteristics, namely, energy efficiency, correlation model, evaluation method, and detection accuracy. The design guidelines given in this paper aim at providing an insight into better design of energy-efficient detection approaches in resource-constraint WSNs....... efficiency to facilitate the design of fault detection methods and the evaluation of their energy efficiency. Following the same design principle of the fault detection framework, the paper proposes a classification for fault detection approaches. The classification is applied to a number of fault detection...

  20. Detecting Unrealizability of Distributed Fault-tolerant Systems

    OpenAIRE

    Finkbeiner, Bernd; Tentrup, Leander

    2015-01-01

    Writing formal specifications for distributed systems is difficult. Even simple consistency requirements often turn out to be unrealizable because of the complicated information flow in the distributed system: not all information is available in every component, and information transmitted from other components may arrive with a delay or not at all, especially in the presence of faults. The problem of checking the distributed realizability of a temporal specification is, in general, undecidab...

  1. Fault detection of helicopter gearboxes using the multi-valued influence matrix method

    Science.gov (United States)

    Chin, Hsinyung; Danai, Kourosh; Lewicki, David G.

    1993-01-01

    In this paper we investigate the effectiveness of a pattern classifying fault detection system that is designed to cope with the variability of fault signatures inherent in helicopter gearboxes. For detection, the measurements are monitored on-line and flagged upon the detection of abnormalities, so that they can be attributed to a faulty or normal case. As such, the detection system is composed of two components, a quantization matrix to flag the measurements, and a multi-valued influence matrix (MVIM) that represents the behavior of measurements during normal operation and at fault instances. Both the quantization matrix and influence matrix are tuned during a training session so as to minimize the error in detection. To demonstrate the effectiveness of this detection system, it was applied to vibration measurements collected from a helicopter gearbox during normal operation and at various fault instances. The results indicate that the MVIM method provides excellent results when the full range of faults effects on the measurements are included in the training set.

  2. Real-Time Model-Based Fault Detection of Continuous Glucose Sensor Measurements.

    Science.gov (United States)

    Turksoy, Kamuran; Roy, Anirban; Cinar, Ali

    2017-07-01

    Faults in subcutaneous glucose concentration readings with a continuous glucose monitoring (CGM) may affect the computation of insulin infusion rates that can lead to hypoglycemia or hyperglycemia in artificial pancreas control systems for patients with type 1 diabetes (T1D). Multivariable statistical monitoring methods are proposed for detection of faults in glucose concentration values reported by a subcutaneous glucose sensor. A nonlinear first principle glucose/insulin/meal dynamic model is developed. An unscented Kalman filter is used for state and parameter estimation of the nonlinear model. Principal component analysis models are developed and used for detection of dynamic changes. K-nearest neighbor classification algorithm is used for diagnosis of faults. Data from 51 subjects are used to assess the performance of the algorithm. The results indicate that the proposed algorithm works successfully with 84.2% sensitivity. Overall, 155 (out of 184) of the CGM failures are detected with a 2.8-min average detection time. A novel algorithm that integrates data-driven and model-based methods is developed. The proposed method is able to detect CGM failures with a high rate of success. The proposed fault detection algorithm can decrease the effects of faults on insulin infusion rates and reduce the potential for hypo- or hyperglycemia for patients with T1D.

  3. Detecting Possible Fault Zone Head Waves Along the Longmenshan Fault Zone Using Aftershocks of the 2013 Mw6.7 Lushan Earthquake

    Science.gov (United States)

    Daniels, C.; Peng, Z.; Li, Z.; Ross, Z. E.; Wu, J.; Su, J.; Zhang, H.; Pei, S.

    2016-12-01

    Fault zone head waves (FZHWs) are subtle refracted waves propagated along bi-material fault interfaces and recorded at stations at slower side of the fault. FZHWs are typically observed in association with mature strike-slip faults or subduction zones, where two sides exhibit a noticeable P-wave velocity difference. So far FZHWs have not been observed along continental thrust faults. In this study we search for possible FZHWs using abundant aftershock observations following the 2013 Mw6.7 Lushan earthquake. This event occurred along the southern portion of the Longmenshan Fault Zone that separated the Tibetan Plateau and Sichuan Basin in Western China. Recent P-wave tomographic studies have found clear velocity contrasts along this fault, suggesting that events occurred at the fault boundary are capable of producing FZHW-like signals. We are in the process of analyzing 4100 aftershocks recorded by 28 temporary stations deployed between April 24 to May 19 2013. We use both visual inspections and automatic FZHW pickers to identify weak precursory-type signals before sharp direct P wave arrivals. Next, we align them on the P-wave onset, and examine the moveout between the time delays of P and weak arrivals and distance along the fault strike. So far we find that many stations on both sides of the fault recorded possible evidence of FZHWs, but we do not find clear moveout with along-strike distances. Our next step is to combine this dataset with another larger dataset recorded by both permanent and temporary stations, and use automatic FZHW pickers to quantify the existences of FZHWs in this region. A systematic detection of FZHW along continental thrust faults could provide new insights on the fault geometry and high-resolution fault interface properties at seismogenic depth.

  4. Active fault and other geological studies for seismic assessment: present state and problems

    Energy Technology Data Exchange (ETDEWEB)

    Kakimi, Toshihiro [Nuclear Power Engineering Corp., Tokyo (Japan)

    1997-03-01

    Evaluation system of earthquakes from an active fault is, in Japan, based on the characteristic earthquake model of a wide sense that postulates essentially the same (nearly the maximum) magnitude and recurrence interval during the recent geological times. Earthquake magnitude M is estimated by empirical relations among M, surface rupture length L, and surface fault displacement D per event of the earthquake faults on land in Japan. Recurrence interval R of faulting/earthquake is calculated from D and the long-term slip rate S of a fault as R=D/S. Grouping or segmentation of complicatedly distributed faults is an important, but difficult problem in order to distinguish a seismogenic fault unit corresponding to an individual characteristic earthquake. If the time t of the latest event is obtained, the `cautiousness` of a fault can be judged from R-t or t/R. According to this idea, several faults whose t/R exceed 0.5 have been designated as the `precaution faults` having higher probability of earthquake occurrence than the others. A part of above evaluation has been introduced at first into the seismic-safety examination system of NPPs in 1978. According to the progress of research on active faults, the weight of interest in respect to the seismic hazard assessment shifted gradually from the historic data to the fault data. Most of recent seismic hazard maps have been prepared in consideration with active faults on land in Japan. Since the occurrence of the 1995 Hyogoken-Nanbu earthquake, social attention has been concentrated upon the seismic hazard due to active faults, because this event was generated from a well-known active fault zone that had been warned as a `precaution fault`. In this paper, a few recent topics on other geological and geotechnical researches aiming at improving the seismic safety of NPPs in Japan were also introduced. (J.P.N.)

  5. Hybrid Model-Based and Data-Driven Fault Detection and Diagnostics for Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Stephen; Heaney, Michael; Jin, Xin; Robertson, Joseph; Cheung, Howard; Elmore, Ryan; Henze, Gregor

    2016-08-26

    Commercial buildings often experience faults that produce undesirable behavior in building systems. Building faults waste energy, decrease occupants' comfort, and increase operating costs. Automated fault detection and diagnosis (FDD) tools for buildings help building owners discover and identify the root causes of faults in building systems, equipment, and controls. Proper implementation of FDD has the potential to simultaneously improve comfort, reduce energy use, and narrow the gap between actual and optimal building performance. However, conventional rule-based FDD requires expensive instrumentation and valuable engineering labor, which limit deployment opportunities. This paper presents a hybrid, automated FDD approach that combines building energy models and statistical learning tools to detect and diagnose faults noninvasively, using minimal sensors, with little customization. We compare and contrast the performance of several hybrid FDD algorithms for a small security building. Our results indicate that the algorithms can detect and diagnose several common faults, but more work is required to reduce false positive rates and improve diagnosis accuracy.

  6. Hybrid Model-Based and Data-Driven Fault Detection and Diagnostics for Commercial Buildings: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Stephen; Heaney, Michael; Jin, Xin; Robertson, Joseph; Cheung, Howard; Elmore, Ryan; Henze, Gregor

    2016-08-01

    Commercial buildings often experience faults that produce undesirable behavior in building systems. Building faults waste energy, decrease occupants' comfort, and increase operating costs. Automated fault detection and diagnosis (FDD) tools for buildings help building owners discover and identify the root causes of faults in building systems, equipment, and controls. Proper implementation of FDD has the potential to simultaneously improve comfort, reduce energy use, and narrow the gap between actual and optimal building performance. However, conventional rule-based FDD requires expensive instrumentation and valuable engineering labor, which limit deployment opportunities. This paper presents a hybrid, automated FDD approach that combines building energy models and statistical learning tools to detect and diagnose faults noninvasively, using minimal sensors, with little customization. We compare and contrast the performance of several hybrid FDD algorithms for a small security building. Our results indicate that the algorithms can detect and diagnose several common faults, but more work is required to reduce false positive rates and improve diagnosis accuracy.

  7. Fault Detection of a Wheelset Bearing Based on Appropriately Sparse Impulse Extraction

    Directory of Open Access Journals (Sweden)

    Jianming Ding

    2017-01-01

    Full Text Available Convolution sparse representation (CSR is a novel compressive sensing technique proposed in 2016 and provides an excellent framework for extracting the impulses induced by bearing faults and the unevenness of wheel tread. However, its sparsity performance on extracting impulses is sensitive to the improper penalty parameter. So, a novel fault detection method, appropriately sparse impulse extraction, is proposed based on the combination of CSR, estimating the number of atom types (ENA, and crest factor. The type of atoms embedded in vibration signals is estimated by ENA. Aiming at the different types of atoms, the impulses with different sparse characteristic are spanned by CSR with different penalty parameters. The appropriately sparse impulses are selected for fault detection based on the maximal crest factor. The simulation validation, experiment verification, and practical application are conducted to validate the effectiveness of the proposed appropriately sparse impulses extraction. These results show that the proposed appropriately sparse impulse extraction not only can obtain fault-characteristic frequency and its harmonics for fault judgment but also describes the dynamic behaviour between elementary defects and their matching surfaces. In addition, the proposed appropriately sparse impulse extraction can isolate the impulses with different types of atoms and is very suitable for detecting the wheelset bearing faults.

  8. Fault detection of a spur gear using vibration signal with multivariable statistical parameters

    Directory of Open Access Journals (Sweden)

    Songpon Klinchaeam

    2014-10-01

    Full Text Available This paper presents a condition monitoring technique of a spur gear fault detection using vibration signal analysis based on time domain. Vibration signals were acquired from gearboxes and used to simulate various faults on spur gear tooth. In this study, vibration signals were applied to monitor a normal and various fault conditions of a spur gear such as normal, scuffing defect, crack defect and broken tooth. The statistical parameters of vibration signal were used to compare and evaluate the value of fault condition. This technique can be applied to set alarm limit of the signal condition based on statistical parameter such as variance, kurtosis, rms and crest factor. These parameters can be used to set as a boundary decision of signal condition. From the results, the vibration signal analysis with single statistical parameter is unclear to predict fault of the spur gears. The using at least two statistical parameters can be clearly used to separate in every case of fault detection. The boundary decision of statistical parameter with the 99.7% certainty ( 3   from 300 referenced dataset and detected the testing condition with 99.7% ( 3   accuracy and had an error of less than 0.3 % using 50 testing dataset.

  9. Rolling Bearing Fault Detection Based on the Teager Energy Operator and Elman Neural Network

    Directory of Open Access Journals (Sweden)

    Hongmei Liu

    2013-01-01

    Full Text Available This paper presents an approach to bearing fault diagnosis based on the Teager energy operator (TEO and Elman neural network. The TEO can estimate the total mechanical energy required to generate signals, thereby resulting in good time resolution and self-adaptability to transient signals. These attributes reflect the advantage of detecting signal impact characteristics. To detect the impact characteristics of the vibration signals of bearing faults, we used the TEO to extract the cyclical impact caused by bearing failure and applied the wavelet packet to reduce the noise of the Teager energy signal. This approach also enabled the extraction of bearing fault feature frequencies, which were identified using the fast Fourier transform of Teager energy. The feature frequencies of the inner and outer faults, as well as the ratio of resonance frequency band energy to total energy in the Teager spectrum, were extracted as feature vectors. In order to avoid a frequency leak error, the weighted Teager spectrum around the fault frequency was extracted as feature vector. These vectors were then used to train the Elman neural network and improve the robustness of the diagnostic algorithm. Experimental results indicate that the proposed approach effectively detects bearing faults under variable conditions.

  10. Fault Detection Enhancement in Rolling Element Bearings via Peak-Based Multiscale Decomposition and Envelope Demodulation

    Directory of Open Access Journals (Sweden)

    Hua-Qing Wang

    2014-01-01

    Full Text Available Vibration signals of rolling element bearings faults are usually immersed in background noise, which makes it difficult to detect the faults. Wavelet-based methods being used commonly can reduce some types of noise, but there is still plenty of room for improvement due to the insufficient sparseness of vibration signals in wavelet domain. In this work, in order to eliminate noise and enhance the weak fault detection, a new kind of peak-based approach combined with multiscale decomposition and envelope demodulation is developed. First, to preserve effective middle-low frequency signals while making high frequency noise more significant, a peak-based piecewise recombination is utilized to convert middle frequency components into low frequency ones. The newly generated signal becomes so smoother that it will have a sparser representation in wavelet domain. Then a noise threshold is applied after wavelet multiscale decomposition, followed by inverse wavelet transform and backward peak-based piecewise transform. Finally, the amplitude of fault characteristic frequency is enhanced by means of envelope demodulation. The effectiveness of the proposed method is validated by rolling bearings faults experiments. Compared with traditional wavelet-based analysis, experimental results show that fault features can be enhanced significantly and detected easily by the proposed method.

  11. A Novel Method for Detection and Classification of Covered Conductor Faults

    Directory of Open Access Journals (Sweden)

    Stanislav Misak

    2016-01-01

    Full Text Available Medium-Voltage (MV overhead lines with Covered Conductors (CCs are increasingly being used around the world primarily in forested or dissected terrain areas or in urban areas where it is not possible to utilize MV cable lines. The CC is specific in high operational reliability provided by the conductor core insulation compared to Aluminium-Conductor Steel-Reinforced (ACSR overhead lines. The only disadvantage of the CC is rather the problematic detection of faults compared to the ACSR. In this work, we consider the following faults: the contact of a tree branch with a CC and the fall of a conductor on the ground. The standard protection relays are unable to detect the faults and so the faults pose a risk for individuals in the vicinity of the conductor as well as it compromises the overall safety and reliability of the MV distribution system. In this article, we continue with our previous work aimed at the method enabling detection of the faults and we introduce a method enabling a classification of the fault type. Such a classification is especially important for an operator of an MV distribution system to plan the optimal maintenance or repair the faulty conductors since the fall of a tree branch can be solved later whereas the breakdown of a conductor means an immediate action of the operator.

  12. Incipient Stator Insulation Fault Detection of Permanent Magnet Synchronous Wind Generators Based on Hilbert–Huang Transformation

    DEFF Research Database (Denmark)

    Wang, Chao; Liu, Xiao; Chen, Zhe

    2014-01-01

    Incipient stator winding fault in permanent magnet synchronous wind generators (PMSWGs) is very difficult to be detected as the fault generated variations in terminal electrical parameters are very weak and chaotic. This paper simulates the incipient stator winding faults at different degree...

  13. Induced Voltages Ratio-Based Algorithm for Fault Detection, and Faulted Phase and Winding Identification of a Three-Winding Power Transformer

    Directory of Open Access Journals (Sweden)

    Byung Eun Lee

    2014-09-01

    Full Text Available This paper proposes an algorithm for fault detection, faulted phase and winding identification of a three-winding power transformer based on the induced voltages in the electrical power system. The ratio of the induced voltages of the primary-secondary, primary-tertiary and secondary-tertiary windings is the same as the corresponding turns ratio during normal operating conditions, magnetic inrush, and over-excitation. It differs from the turns ratio during an internal fault. For a single phase and a three-phase power transformer with wye-connected windings, the induced voltages of each pair of windings are estimated. For a three-phase power transformer with delta-connected windings, the induced voltage differences are estimated to use the line currents, because the delta winding currents are practically unavailable. Six detectors are suggested for fault detection. An additional three detectors and a rule for faulted phase and winding identification are presented as well. The proposed algorithm can not only detect an internal fault, but also identify the faulted phase and winding of a three-winding power transformer. The various test results with Electromagnetic Transients Program (EMTP-generated data show that the proposed algorithm successfully discriminates internal faults from normal operating conditions including magnetic inrush and over-excitation. This paper concludes by implementing the algorithm into a prototype relay based on a digital signal processor.

  14. Improved Data-based Fault Detection Strategy and Application to Distillation Columns

    KAUST Repository

    Madakyaru, Muddu

    2017-01-31

    Chemical and petrochemical processes require continuous monitoring to detect abnormal events and to sustain normal operations. Furthermore, process monitoring enhances productivity, efficiency, and safety in process industries. Here, we propose an innovative statistical approach that exploits the advantages of multiscale partial least squares (MSPLS) models and generalized likelihood ratio (GLR) tests for fault detection in processes. Specifically, we combine an MSPLS algorithm with wavelet analysis to create our modeling framework. Then, we use GLR hypothesis testing based on the uncorrelated residuals obtained from the MSPLS model to improve fault detection. We use simulated distillation column data to evaluate the MSPLS-based GLR chart. Results show that our MSPLS-based GLR method is more powerful than the PLS-based Q and GLR method and MSPLS-based Q method, especially in early detection of small faults with abrupt or incipient behavior.

  15. Distributed Fault Detection and Isolation for Flocking in a Multi-robot System with Imperfect Communication

    Directory of Open Access Journals (Sweden)

    Shao Shiliang

    2014-06-01

    Full Text Available In this paper, we focus on distributed fault detection and isolation (FDI for a multi-robot system where multiple robots execute a flocking task. Firstly, we propose a fault detection method based on the local-information-exchange and sensor-measurement technologies to cover cases of both perfect communication and imperfect communication. The two detection technologies can be adaptively selected according to the packet loss rate (PLR. Secondly, we design a fault isolation method, considering a situation in which faulty robots still influence the behaviours of other robots. Finally, a complete FDI scheme, based on the proposed detection and isolation methods, is simulated in various scenarios. The results demonstrate that our FDI scheme is effective.

  16. A hybrid fault detection and isolation strategy for a team of cooperating unmanned vehicles

    Science.gov (United States)

    Tousi, M. M.; Khorasani, K.

    2015-01-01

    In this paper, a hybrid fault detection and isolation (FDI) methodology is developed for a team of cooperating unmanned vehicles. The proposed approach takes advantage of the cooperative nature of the team to detect and isolate relatively low-severity actuator faults that are otherwise not detectable and isolable by the vehicles themselves individually. The approach is hybrid and consists of both low-level (agent/team level) and high-level [discrete-event systems (DES) level] FDI modules. The high-level FDI module is formulated in the DES supervisory control framework, whereas the low-level FDI module invokes classical FDI techniques. By properly integrating the two FDI modules, a larger class of faults can be detected and isolated as compared to the existing techniques in the literature that rely on each level separately. Simulation results for a team of five unmanned aerial vehicles are also presented to demonstrate the effectiveness and capabilities of our proposed methodology.

  17. Fault Detection in WSNs - An Energy Efficiency Perspective Towards Human-Centric WSNs

    DEFF Research Database (Denmark)

    Orfanidis, Charalampos; Zhang, Yue; Dragoni, Nicola

    2015-01-01

    Energy efficiency is a key factor to prolong the lifetime of wireless sensor networks (WSNs). This is particularly true in the design of human-centric wireless sensor networks (HCWSN) where sensors are more and more embedded and they have to work in resource-constraint settings. Resource limitation...... has a significant impact on the design of a WSN and the adopted fault detection method. This paper investigates a number of fault detection approaches and proposes a fault detection framework based on an energy efficiency perspective. The analysis and design guidelines given in this paper aims...... at representing a first step towards the design of energy-efficient detection approaches in resource-constraint WSN, like HCWSNs....

  18. Early fault detection and on-line diagnosis in real-time environments

    Directory of Open Access Journals (Sweden)

    Andreas Bye

    1993-01-01

    Full Text Available This paper describes an approach to fault detection and diagnosis involving the simultaneous employment of quantitative and qualitative reasoning techniques. We show that early identification of process anomalies by means of a separate fault detection module paves the way for a fast and accuratc follow-up diagnosis. The diagnosis task is dramatically simplified because the diagnostic inferences can be performed at the soonest possible time: when the detection module first spots deviations between its calculated reference points and the corresponding measurements from the process.

  19. A Probabilistic Approach for the Evaluation of Fault Detection Schemes in Microgrids

    Directory of Open Access Journals (Sweden)

    R. Eslami

    2017-10-01

    Full Text Available An important challenge in protection of a microgrid is the process of fault detection, considering the uncertainties in its topologies. Equally important is the evaluation of proposed methods as their incorrect performances could result in unreasonable power outages. In this paper, a new fault detection and characterization method is introduced and evaluated subject to the uncertainties of network topologies. The features of three-phase components together with the positive, negative and zero sequences of current and voltage waveforms are derived to detect the occurrence of a fault, its location, type and the engaged phases. The proposed method is independent of the microgrid topology. To evaluate the performance of the proposed method in various network topologies, a Monte Carlo scheme is developed. This is done by computing the expected energy not-supplied reliability index and the percentage of successful performance of the fault detection. Simulation results show that the proposed method can detect faults in various microgrid topologies with a very high degree of accuracy.

  20. Bearing fault detection utilizing group delay and the Hilbert-Huang transform

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Shuai; Lee, Sang-Kwon [Inha University, Incheon (Korea, Republic of)

    2017-03-15

    Vibration signals measured from a mechanical system are useful to detect system faults. Signal processing has been used to extract fault information in bearing systems. However, a wide vibration signal frequency band often affects the ability to obtain the effective fault features. In addition, a few oscillation components are not useful at the entire frequency band in a vibration signal. By contrast, useful fatigue information can be embedded in the noise oscillation components. Thus, a method to estimate which frequency band contains fault information utilizing group delay was proposed in this paper. Group delay as a measure of phase distortion can indicate the phase structure relationship in the frequency domain between original (with noise) and denoising signals. We used the empirical mode decomposition of a Hilbert-Huang transform to sift the useful intrinsic mode functions based on the results of group delay after determining the valuable frequency band. Finally, envelope analysis and the energy distribution after the Hilbert transform were used to complete the fault diagnosis. The practical bearing fault data, which were divided into inner and outer race faults, were used to verify the efficiency and quality of the proposed method.

  1. Development of Fault Detection and Diagnosis Schemes for Industrial Refrigeration Systems

    DEFF Research Database (Denmark)

    Thybo, C.; Izadi-Zamanabadi, Roozbeh

    2004-01-01

    The success of a fault detection and diagnosis (FDD) scheme depends not alone on developing an advanced detection scheme. To enable successful deployment in industrial applications, an economically optimal development of FDD schemes are required. This paper reviews and discusses the gained experi...

  2. Fault kinematics and active tectonics at the southeastern boundary of the eastern Alborz (Abr and Khij fault zones): Geodynamic implications for NNE Iran

    Science.gov (United States)

    Javidfakhr, Bita; Bellier, Olivier; Shabanian, Esmaeil; Siame, Lionel; Léanni, Laëtitia; Bourlès, Didier; Ahmadian, Seiran

    2011-10-01

    The Alborz is a region of active deformation within the Arabia-Eurasia collision zone. The Abr and the Khij Faults are two NE-trending left-lateral strike-slip faults in the eastern Alborz that correspond to the Shahrud fault system extended through an area of about 95 km × 55 km. Tectonic landforms typically associated with active strike-slip faults, such as deflected stream channels, offset ridges and fault scarps are documented along the mentioned faults. Detailed analyses of satellite images and digital topographic data accompanied by field surveys allowed us to measure horizontal offsets of about 420 ± 50 m and 400 ± 50 m for the Abr and Khij Faults, respectively. A total of 8 quartz-rich samples were sampled and dated from two different fan surfaces using in situ-produced 10Be cosmogenic dating method. Minimum exposure ages for the abandonment of the alluvial fan surfaces of 115 ± 14 kyr along the Abr Fault and of 230 ± 16 kyr along the Khij Fault imply that both faults are active with slip rates of about 3-4 mm yr -1 and 1-3 mm yr -1, respectively. The results of our study provide the first direct quantitative geological estimates of slip rate along these two active faults and place a new constraint on slip distribution between the faults in the eastern Alborz. Fault kinematic studies (from fault slip data) indicate a N35°E-trending maximum stress axis comprising a dominant strike-slip regime in agreement with the geomorphological analyses. The left-lateral strike-slip faulting along the Abr and Khij Faults and their associated fault zones in the eastern Alborz can be due to the westward component of motion of the South Caspian Basin with respect to Eurasia and Central Iran.

  3. Nuclear Power Plant Thermocouple Sensor-Fault Detection and Classification Using Deep Learning and Generalized Likelihood Ratio Test

    Science.gov (United States)

    Mandal, Shyamapada; Santhi, B.; Sridhar, S.; Vinolia, K.; Swaminathan, P.

    2017-06-01

    In this paper, an online fault detection and classification method is proposed for thermocouples used in nuclear power plants. In the proposed method, the fault data are detected by the classification method, which classifies the fault data from the normal data. Deep belief network (DBN), a technique for deep learning, is applied to classify the fault data. The DBN has a multilayer feature extraction scheme, which is highly sensitive to a small variation of data. Since the classification method is unable to detect the faulty sensor; therefore, a technique is proposed to identify the faulty sensor from the fault data. Finally, the composite statistical hypothesis test, namely generalized likelihood ratio test, is applied to compute the fault pattern of the faulty sensor signal based on the magnitude of the fault. The performance of the proposed method is validated by field data obtained from thermocouple sensors of the fast breeder test reactor.

  4. A new SKRgram based demodulation technique for planet bearing fault detection

    Science.gov (United States)

    Wang, Tianyang; Han, Qinkai; Chu, Fulei; Feng, Zhipeng

    2016-12-01

    Planet bearing fault detection is one of the most challenging issues in planetary gearbox condition monitoring. The intricate structure of a planetary gearbox will fail traditional bearing fault diagnosis algorithms by bringing in strong and complex planetary gear noise. In specific, planetary gear noise with multi-sidebands and high magnitude will not only fail the former gear noise elimination algorithms but also affect the methods designed for highlighting bearing-fault-related content. As such, we propose a new approach with four main steps to address this issue: a) calculate the spectral kurtosis (SK) matrix of a healthy planetary gearbox as baseline, b) obtain SKRgram (Spectral kurtosis ratio gram) by calculating the ratio between SK matrix of raw signal and the baseline, c) locate potential filtering areas from the SKRgram using SKR value as criterion and then select potential optimal filter bands among them with the standard of kurtosis value, d) highlight the faulty planet bearing content by filtering the raw signal through potential filter bands and identify the fault type of planet bearing by comparing the filtered results with the fault envelope pattern. The accuracy and effectiveness of the proposed planet bearing fault detection algorithm are verified by both the simulated and experimental data.

  5. Comprehensive bearing condition monitoring algorithm for incipient fault detection using acoustic emission

    Directory of Open Access Journals (Sweden)

    Amit R. Bhende

    2014-09-01

    Full Text Available The bearing reliability plays major role in obtaining the desired performance of any machine. A continuous condition monitoring of machine is required in certain applications where failure of machine leads to loss of production, human safety and precision. Machine faults are often linked to the bearing faults. Condition monitoring of machine involves continuous watch on the performance of bearings and predicting the faults of bearing before it cause any adversity. This paper investigates an experimental study to diagnose the fault while bearing is in operation. An acoustic emission technique is used in the experimentation. An algorithm is developed to process various types of signals generated from different bearing defects. The algorithm uses time domain analysis along with combination low frequency analysis technique such as fast Fourier transform and high frequency envelope detection. Two methods have adopted for envelope detection which are Hilbert transform and order analysis. Experimental study is carried out for deep groove ball bearing cage defect. Results show the potential effectiveness of the proposed algorithm to determine presence of fault, exact location and severity of fault.

  6. Application of fault detection and identification (FDI) techniques in power regulating systems of nuclear reactors

    Science.gov (United States)

    Roy, K.; Banavar, R. N.; Thangasamy, S.

    1998-12-01

    Application of failure detection and identification (FDI) algorithms have essentially been limited to identification of a global fault in the system, and no further attempts have been made to locate subcomponent faults for root cause analysis. This paper presents Kalman filter-based methods for FDI in power regulating systems of nuclear reactors. The attempt here is to explain how the behavior of the states, residues, and covariances can be interpreted to identify subcomponent faults. An alternative to the Kalman filter-the risk-sensitive filter-is also introduced. Comparison of its performance with the Kalman filter-based FDI algorithms is studied. All simulation studies have been carried out on postulated faults in the power regulating system of heavy water moderated, low pressure vertical tank-type research reactors.

  7. Fuzzy logic based on-line fault detection and classification in transmission line.

    Science.gov (United States)

    Adhikari, Shuma; Sinha, Nidul; Dorendrajit, Thingam

    2016-01-01

    This study presents fuzzy logic based online fault detection and classification of transmission line using Programmable Automation and Control technology based National Instrument Compact Reconfigurable i/o (CRIO) devices. The LabVIEW software combined with CRIO can perform real time data acquisition of transmission line. When fault occurs in the system current waveforms are distorted due to transients and their pattern changes according to the type of fault in the system. The three phase alternating current, zero sequence and positive sequence current data generated by LabVIEW through CRIO-9067 are processed directly for relaying. The result shows that proposed technique is capable of right tripping action and classification of type of fault at high speed therefore can be employed in practical application.

  8. PLAT: An Automated Fault and Behavioural Anomaly Detection Tool for PLC Controlled Manufacturing Systems.

    Science.gov (United States)

    Ghosh, Arup; Qin, Shiming; Lee, Jooyeoun; Wang, Gi-Nam

    2016-01-01

    Operational faults and behavioural anomalies associated with PLC control processes take place often in a manufacturing system. Real time identification of these operational faults and behavioural anomalies is necessary in the manufacturing industry. In this paper, we present an automated tool, called PLC Log-Data Analysis Tool (PLAT) that can detect them by using log-data records of the PLC signals. PLAT automatically creates a nominal model of the PLC control process and employs a novel hash table based indexing and searching scheme to satisfy those purposes. Our experiments show that PLAT is significantly fast, provides real time identification of operational faults and behavioural anomalies, and can execute within a small memory footprint. In addition, PLAT can easily handle a large manufacturing system with a reasonable computing configuration and can be installed in parallel to the data logging system to identify operational faults and behavioural anomalies effectively.

  9. PLAT: An Automated Fault and Behavioural Anomaly Detection Tool for PLC Controlled Manufacturing Systems

    Directory of Open Access Journals (Sweden)

    Arup Ghosh

    2016-01-01

    Full Text Available Operational faults and behavioural anomalies associated with PLC control processes take place often in a manufacturing system. Real time identification of these operational faults and behavioural anomalies is necessary in the manufacturing industry. In this paper, we present an automated tool, called PLC Log-Data Analysis Tool (PLAT that can detect them by using log-data records of the PLC signals. PLAT automatically creates a nominal model of the PLC control process and employs a novel hash table based indexing and searching scheme to satisfy those purposes. Our experiments show that PLAT is significantly fast, provides real time identification of operational faults and behavioural anomalies, and can execute within a small memory footprint. In addition, PLAT can easily handle a large manufacturing system with a reasonable computing configuration and can be installed in parallel to the data logging system to identify operational faults and behavioural anomalies effectively.

  10. GMDH and neural networks applied in monitoring and fault detection in sensors in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Elaine Inacio [Instituto Federal de Educacao, Ciencia e Tecnologia, Guarulhos, SP (Brazil); Pereira, Iraci Martinez; Silva, Antonio Teixeira e, E-mail: martinez@ipen.b, E-mail: teixeira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    In this work a new monitoring and fault detection methodology was developed using GMDH (Group Method of Data Handling) algorithm and artificial neural networks (ANNs) which was applied in the IEA-R1 research reactor at IPEN. The monitoring and fault detection system was developed in two parts: the first was dedicated to preprocess information, using GMDH algorithm; and the second to the process information using ANNs. The preprocess information was divided in two parts. In the first part, the GMDH algorithm was used to generate a better database estimate, called matrix z, which was used to train the ANNs. In the second part the GMDH was used to study the best set of variables to be used to train the ANNs, resulting in a best monitoring variable estimative. The methodology was developed and tested using five different models: one theoretical model and for models using different sets of reactor variables. After an exhausting study dedicated to the sensors monitoring, the fault detection in sensors was developed by simulating faults in the sensors database using values of +5%, +10%, +15% and +20% in these sensors database. The good results obtained through the present methodology shows the viability of using GMDH algorithm in the study of the best input variables to the ANNs, thus making possible the use of these methods in the implementation of a new monitoring and fault detection methodology applied in sensors. (author)

  11. Improved nonlinear fault detection strategy based on the Hellinger distance metric: Plug flow reactor monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-03-18

    Fault detection has a vital role in the process industry to enhance productivity, efficiency, and safety, and to avoid expensive maintenance. This paper proposes an innovative multivariate fault detection method that can be used for monitoring nonlinear processes. The proposed method merges advantages of nonlinear projection to latent structures (NLPLS) modeling and those of Hellinger distance (HD) metric to identify abnormal changes in highly correlated multivariate data. Specifically, the HD is used to quantify the dissimilarity between current NLPLS-based residual and reference probability distributions obtained using fault-free data. Furthermore, to enhance further the robustness of these methods to measurement noise, and reduce the false alarms due to modeling errors, wavelet-based multiscale filtering of residuals is used before the application of the HD-based monitoring scheme. The performances of the developed NLPLS-HD fault detection technique is illustrated using simulated plug flow reactor data. The results show that the proposed method provides favorable performance for detection of faults compared to the conventional NLPLS method.

  12. The northwest trending north Boquerón Bay-Punta Montalva Fault Zone; A through going active fault system in southwestern Puerto Rico

    Science.gov (United States)

    Roig‐Silva, Coral Marie; Asencio, Eugenio; Joyce, James

    2013-01-01

    The North Boquerón Bay–Punta Montalva fault zone has been mapped crossing the Lajas Valley in southwest Puerto Rico. Identification of the fault was based upon detailed analysis of geophysical data, satellite images, and field mapping. The fault zone consists of a series of Cretaceous bedrock faults that reactivated and deformed Miocene limestone and Quaternary alluvial fan sediments. The fault zone is seismically active (local magnitude greater than 5.0) with numerous locally felt earthquakes. Focal mechanism solutions suggest strain partitioning with predominantly east–west left-lateral displacements with small normal faults striking mostly toward the northeast. Northeast-trending fractures and normal faults can be found in intermittent streams that cut through the Quaternary alluvial fan deposits along the southern margin of the Lajas Valley, an east–west-trending 30-km-long fault-controlled depression. Areas of preferred erosion within the alluvial fan trend toward the west-northwest parallel to the onland projection of the North Boquerón Bay fault. The North Boquerón Bay fault aligns with the Punta Montalva fault southeast of the Lajas Valley. Both faults show strong southward tilting of Miocene strata. On the western end, the Northern Boquerón Bay fault is covered with flat-lying Holocene sediments, whereas at the southern end the Punta Montalva fault shows left-lateral displacement of stream drainage on the order of a few hundred meters.

  13. Non-tectonic exposure Rates along Bedrock Fault Scarps in an active Mountain Belt of the central Apennines

    Science.gov (United States)

    Kastelic, Vanja; Burrato, Pierfrancesco; Carafa, Michele M. C.; Basili, Roberto

    2017-04-01

    The central Apennines (Italy) are a mountain chain affected by post-collisional active extension along NW-SE striking normal faults and well-documented regional-scale uplift. Moderate to strong earthquakes along the seismogenically active extensional faults are frequent in this area, thus a good knowledge on the characteristics of the hosting faults is necessary for realistic seismic hazard models. The studied bedrock fault surfaces are generally located at various heights on mountain fronts above the local base level of glacio-fluvial valleys and intermountain fluvio-lacustrine basins and are laterally confined to the extent of related mountain fronts. In order to investigate the exposure of the bedrock fault scarps from under their slope-deposit cover, a process that has often been exclusively attributed to co-seismic earthquake slip and used as proxy for tectonic slip rates and earthquake recurrence estimations, we have set up a measurement experiment along various such structures. In this experiment we measure the relative position of chosen markers on the bedrock surface and the material found directly at the contact with its hanging wall. We present the results of monitoring the contact between the exposed fault surfaces and slope deposits at 23 measurement points on 12 different faults over 3.4 year-long observation period. We detected either downward or upward movements of the slope deposit with respect to the fault surface between consecutive measurements. During the entire observation period all points, except one, registered a net downward movement in the 2.9 - 25.6 mm/yr range, resulting in the progressive exposure of the fault surface. During the monitoring period no major earthquakes occurred in the region, demonstrating the measured exposure process is disconnected from seismic activity. We do however observe a positive correlation between the higher exposure in respect to higher average temperatures. Our results indicate that the fault surface

  14. Data-driven fault detection for industrial processes canonical correlation analysis and projection based methods

    CERN Document Server

    Chen, Zhiwen

    2017-01-01

    Zhiwen Chen aims to develop advanced fault detection (FD) methods for the monitoring of industrial processes. With the ever increasing demands on reliability and safety in industrial processes, fault detection has become an important issue. Although the model-based fault detection theory has been well studied in the past decades, its applications are limited to large-scale industrial processes because it is difficult to build accurate models. Furthermore, motivated by the limitations of existing data-driven FD methods, novel canonical correlation analysis (CCA) and projection-based methods are proposed from the perspectives of process input and output data, less engineering effort and wide application scope. For performance evaluation of FD methods, a new index is also developed. Contents A New Index for Performance Evaluation of FD Methods CCA-based FD Method for the Monitoring of Stationary Processes Projection-based FD Method for the Monitoring of Dynamic Processes Benchmark Study and Real-Time Implementat...

  15. A Novel Approach to Fault Detection in Complex Electric Power Systems

    Directory of Open Access Journals (Sweden)

    ZHANG, Y.

    2014-08-01

    Full Text Available The new type of backup protection can utilize different kinds of information in a larger scale. The research of this paper is focused on the centralized decision and distributed implementation of wide area backup protection system in large-scale power grid. Topology analysis of power network is substantially network connectivity judgment. The operation conditions in case of a failure should be truthfully reflected in the actual structure of network topology, which requires the system failure must be detected promptly and accurately, and prepare for the subsequent adjustment of operation scheme. In the research of this paper, for different kinds of complex system failures, we have put forward a novel fault factor analysis scheme which can realize rapid, accurate and effective fault detection. Many simulations have verified that the fault factor analysis can successfully detect the failures in complex electric power system.

  16. Open-switch fault detection method of an NPC converter for wind turbine systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Lee, Kyo-Beum; Blaabjerg, Frede

    2013-01-01

    In wind turbine generation (WTG) systems, the neutral-point-clamped (NPC) topology is widely used as the part of a back-to-back converter since the three-level NPC topology has more advantages than the conventional two-level inverter especially for high power. There are twelve switches in the NPC...... topology and an open-switch fault of the NPC converter leads to current distortion and the torque ripple in the system. Furthermore, WTG systems can breakdown in the worst case by this ripple. To improve the reliability of WTG systems, an open-switch fault detection method is required. The open-switch...... detection method of the NPC converter is different from that of the NPC inverter due to the different current paths of the NPC converter. This paper proposes the open-switch fault detection method of the NPC converter connected the permanent-magnet synchronous generator (PMSG). Moreover, the open-switch...

  17. A Neuro-Augmented Observer for Robust Fault Detection in Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Huajun Gong

    2012-01-01

    Full Text Available A new fault detection method using neural-networks-augmented state observer for nonlinear systems is presented in this paper. The novelty of the approach is that instead of approximating the entire nonlinear system with neural network, we only approximate the unmodeled part that is left over after linearization, in which a radial basis function (RBF neural network is adopted. Compared with conventional linear observer, the proposed observer structure provides more accurate estimation of the system state. The state estimation error is proved to asymptotically approach zero by the Lyapunov method. An aircraft system demonstrates the efficiency of the proposed fault detection scheme, simulation results of which show that the proposed RBF neural network-based observer scheme is effective and has a potential application in fault detection and identification (FDI for nonlinear systems.

  18. A consensus-based multi-agent approach for estimation in robust fault detection.

    Science.gov (United States)

    Jiang, Yulian; Liu, Jianchang; Wang, Shenquan

    2014-09-01

    This paper is devoted to distributed estimation in robust fault detection for sensor networks with networked-induced delays and packet dropouts by using a consensus-based multi-agent approach. Utilizing the information interaction and coordination among the neighboring networks based on multi-agent theory, we design novel and multiple agent-based robust fault detection filters (RFDFs) subject to only partial estimated and measured information. Asymptotically stable sufficient conditions for the innovative constructed filters are derived in the form of linear matrix inequality (LMI) and the threshold fit for each agent-based RFDF is determined. An illustrative example is given to demonstrate the effectiveness of the consensus-based multi-agent approach for the estimation in robust fault detection. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Online model-based fault detection for grid connected PV systems monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-12-14

    This paper presents an efficient fault detection approach to monitor the direct current (DC) side of photovoltaic (PV) systems. The key contribution of this work is combining both single diode model (SDM) flexibility and the cumulative sum (CUSUM) chart efficiency to detect incipient faults. In fact, unknown electrical parameters of SDM are firstly identified using an efficient heuristic algorithm, named Artificial Bee Colony algorithm. Then, based on the identified parameters, a simulation model is built and validated using a co-simulation between Matlab/Simulink and PSIM. Next, the peak power (Pmpp) residuals of the entire PV array are generated based on both real measured and simulated Pmpp values. Residuals are used as the input for the CUSUM scheme to detect potential faults. We validate the effectiveness of this approach using practical data from an actual 20 MWp grid-connected PV system located in the province of Adrar, Algeria.

  20. Shallow Faulting in Morelia, Mexico, Based on Seismic Tomography and Geodetically Detected Land Subsidence

    Science.gov (United States)

    Cabral-Cano, E.; Arciniega-Ceballos, A.; Vergara-Huerta, F.; Chaussard, E.; Wdowinski, S.; DeMets, C.; Salazar-Tlaczani, L.

    2013-12-01

    Subsidence has been a common occurrence in several cities in central Mexico for the past three decades. This process causes substantial damage to the urban infrastructure and housing in several cities and it is a major factor to be considered when planning urban development, land-use zoning and hazard mitigation strategies. Since the early 1980's the city of Morelia in Central Mexico has experienced subsidence associated with groundwater extraction in excess of natural recharge from rainfall. Previous works have focused on the detection and temporal evolution of the subsidence spatial distribution. The most recent InSAR analysis confirms the permanence of previously detected rapidly subsiding areas such as the Rio Grande Meander area and also defines 2 subsidence patches previously undetected in the newly developed suburban sectors west of Morelia at the Fraccionamiento Del Bosque along, south of Hwy. 15 and another patch located north of Morelia along Gabino Castañeda del Rio Ave. Because subsidence-induced, shallow faulting develops at high horizontal strain localization, newly developed a subsidence areas are particularly prone to faulting and fissuring. Shallow faulting increases groundwater vulnerability because it disrupts discharge hydraulic infrastructure and creates a direct path for transport of surface pollutants into the underlying aquifer. Other sectors in Morelia that have been experiencing subsidence for longer time have already developed well defined faults such as La Colina, Central Camionera, Torremolinos and La Paloma faults. Local construction codes in the vicinity of these faults define a very narrow swath along which housing construction is not allowed. In order to better characterize these fault systems and provide better criteria for future municipal construction codes we have surveyed the La Colina and Torremolinos fault systems in the western sector of Morelia using seismic tomographic techniques. Our results indicate that La Colina Fault

  1. Robust fault detection of linear systems using a computationally efficient set-membership method

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Bak, Thomas

    2014-01-01

    In this paper, a computationally efficient set-membership method for robust fault detection of linear systems is proposed. The method computes an interval outer-approximation of the output of the system that is consistent with the model, the bounds on noise and disturbance, and the past measureme...... is trivially parallelizable. The method is demonstrated for fault detection of a hydraulic pitch actuator of a wind turbine. We show the effectiveness of the proposed method by comparing our results with two zonotope-based set-membership methods....

  2. Sensor fault detection and isolation in doubly-fed induction generators accounting for parameter variations

    Energy Technology Data Exchange (ETDEWEB)

    Galvez-Carrillo, Manuel; Kinnaert, Michel [Dept. of Control Engineering and System Analysis, Universite Libre de Bruxelles (ULB), 50 Av. F.D. Roosevelt, CP 165/55, B-1050 Brussels (Belgium)

    2011-05-15

    A fault detection and isolation (FDI) system for monitoring rotor current sensors in a doubly-fed induction generator (DFIG) for wind turbine applications is presented. The FDI system is designed so that the effect of parameter variations (resistances and inductances) is minimized. The residual generation is based on the generalized observer scheme (GOS) including parameter estimation. A decision system made of a combination of vector CUSUM (Cumulative sum) algorithms is used to process the residual vector and to achieve detection and isolation of incipient (small magnitude) faults. The approach is validated using signals obtained from a simulated vector-controlled DFIG. (author)

  3. Observer-based Fault Detection and Isolation for Nonlinear Systems

    DEFF Research Database (Denmark)

    Lootsma, T.F.

    systems. It consists of four different contributions. First, it presents a review of the idea and the theory behind the geometric approach for FDI. Starting from the original solution for linear systems up to the latest results for input-affine systems the theory and solutions are described....... Then the geometric approach is applied to a nonlinear ship propulsion system benchmark. The calculations and application results are presented in detail to give an illustrative example. The obtained subsystems are considered for the design of nonlinear observers in order to obtain FDI. Additionally, an adaptive...... for the observers designed for the ship propulsion system. Furthermore, it stresses the importance of the time-variant character of the linearization along a trajectory. It leads to a different stability analysis than for linearization at one operation point. Finally, the preliminary concept of (actuator) fault...

  4. Detection of Stator Winding Fault in Induction Motor Using Fuzzy Logic with Optimal Rules

    Directory of Open Access Journals (Sweden)

    Hamid Fekri Azgomi

    2013-04-01

    Full Text Available Induction motors are critical components in many industrial processes. Therefore, swift, precise and reliable monitoring and fault detection systems are required to prevent any further damages. The online monitoring of induction motors has been becoming increasingly important. The main difficulty in this task is the lack of an accurate analytical model to describe a faulty motor. A fuzzy logic approach may help to diagnose traction motor faults. This paper presents a simple method for the detection of stator winding faults (which make up 38% of induction motor failures based on monitoring the line/terminal current amplitudes. In this method, fuzzy logic is used to make decisions about the stator motor condition. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The motor condition is described using linguistic variables. Fuzzy subsets and the corresponding membership functions describe stator current amplitudes. A knowledge base, comprising rule and data bases, is built to support the fuzzy inference. Simulation results are presented to verify the accuracy of motor’s fault detection and knowledge extraction feasibility. The preliminary results show that the proposed fuzzy approach can be used for accurate stator fault diagnosis.

  5. Model-based robust estimation and fault detection for MEMS-INS/GPS integrated navigation systems

    Directory of Open Access Journals (Sweden)

    Miao Lingjuan

    2014-08-01

    Full Text Available In micro-electro-mechanical system based inertial navigation system (MEMS-INS/global position system (GPS integrated navigation systems, there exist unknown disturbances and abnormal measurements. In order to obtain high estimation accuracy and enhance detection sensitivity to faults in measurements, this paper deals with the problem of model-based robust estimation (RE and fault detection (FD. A filter gain matrix and a post-filter are designed to obtain a RE and FD algorithm with current measurements, which is different from most of the existing priori filters using measurements in one-step delay. With the designed filter gain matrix, the H-infinity norm of the transfer function from noise inputs to estimation error outputs is limited within a certain range; with the designed post-filter, the residual signal is robust to disturbances but sensitive to faults. Therefore, the algorithm can guarantee small estimation errors in the presence of disturbances and have high sensitivity to faults. The proposed method is evaluated in an integrated navigation system, and the simulation results show that it is more effective in position estimation and fault signal detection than priori RE and FD algorithms.

  6. DIAGNOSTICS OF META-INSTABLE STATE OF SEISMICALLY ACTIVE FAULT

    Directory of Open Access Journals (Sweden)

    S. A. Bornyakov

    2017-01-01

    Full Text Available Based on the results of a laboratory simulation of the seismic fault reactivation by “stick-slip” process, it was shown that the system of two blocks just before an impulse offset goes through the meta-instable dynamic state, with early and late stages of meta-instability [Ma et al., 2012]. In the first stage the offset begins in slow stationary mode with slow stresses relaxation on contact between blocks. In the second stage of the “accelerated synergies” strain rate increases and, subsequently, the deformation process through a process of self-organization came to dynamic impulse offset. The experimental results were used for interpretation of the results of spectral analysis of the deformation monitoring data. The data were held within the southern part ofLakeBaikal, where Kultuk earthquake (27.08.2008, Ms=6.1. took place. Its epicenter was located in the South end zone of the main Sayan fault. Monitoring of deformations of rocks was carried out from April to November2008 in tunnel, located at30 km from the epicenter of the earthquake. The time series data was divided into month periods and then the periods were processed by the method of spectral analysis. The results showed that before the earthquake has ordered view spectrogram, whereas in other time intervals, both before and after the earthquake such orderliness in spectrograms is missing. An ordered view spectrograms for deformation monitoring data can be interpreted as a consequence of the self-organiza­tion of deformation process in the transition of seismically active fault into meta-unstable before the Kultuk earthquake.

  7. Fault Detection of Wind Turbines with Uncertain Parameters: A Set-Membership Approach

    Directory of Open Access Journals (Sweden)

    Thomas Bak

    2012-07-01

    Full Text Available In this paper a set-membership approach for fault detection of a benchmark wind turbine is proposed. The benchmark represents relevant fault scenarios in the control system, including sensor, actuator and system faults. In addition we also consider parameter uncertainties and uncertainties on the torque coefficient. High noise on the wind speed measurement, nonlinearities in the aerodynamic torque and uncertainties on the parameters make fault detection a challenging problem. We use an effective wind speed estimator to reduce the noise on the wind speed measurements. A set-membership approach is used generate a set that contains all states consistent with the past measurements and the given model of the wind turbine including uncertainties and noise. This set represents all possible states the system can be in if not faulty. If the current measurement is not consistent with this set, a fault is detected. For representation of these sets we use zonotopes and for modeling of uncertainties we use matrix zonotopes, which yields a computationally efficient algorithm. The method is applied to the wind turbine benchmark problem without and with uncertainties. The result demonstrates the effectiveness of the proposed method compared to other proposed methods applied to the same problem. An advantage of the proposed method is that there is no need for threshold design, and it does not produce positive false alarms. In the case where uncertainty on the torque lookup table is introduced, some faults are not detectable. Previous research has not addressed this uncertainty. The method proposed here requires equal or less detection time than previous results.

  8. Runtime Verification in Context : Can Optimizing Error Detection Improve Fault Diagnosis

    Science.gov (United States)

    Dwyer, Matthew B.; Purandare, Rahul; Person, Suzette

    2010-01-01

    Runtime verification has primarily been developed and evaluated as a means of enriching the software testing process. While many researchers have pointed to its potential applicability in online approaches to software fault tolerance, there has been a dearth of work exploring the details of how that might be accomplished. In this paper, we describe how a component-oriented approach to software health management exposes the connections between program execution, error detection, fault diagnosis, and recovery. We identify both research challenges and opportunities in exploiting those connections. Specifically, we describe how recent approaches to reducing the overhead of runtime monitoring aimed at error detection might be adapted to reduce the overhead and improve the effectiveness of fault diagnosis.

  9. Voltage Based Detection Method for High Impedance Fault in a Distribution System

    Science.gov (United States)

    Thomas, Mini Shaji; Bhaskar, Namrata; Prakash, Anupama

    2016-09-01

    High-impedance faults (HIFs) on distribution feeders cannot be detected by conventional protection schemes, as HIFs are characterized by their low fault current level and waveform distortion due to the nonlinearity of the ground return path. This paper proposes a method to identify the HIFs in distribution system and isolate the faulty section, to reduce downtime. This method is based on voltage measurements along the distribution feeder and utilizes the sequence components of the voltages. Three models of high impedance faults have been considered and source side and load side breaking of the conductor have been studied in this work to capture a wide range of scenarios. The effect of neutral grounding of the source side transformer is also accounted in this study. The results show that the algorithm detects the HIFs accurately and rapidly. Thus, the faulty section can be isolated and service can be restored to the rest of the consumers.

  10. A Mode-Shape-Based Fault Detection Methodology for Cantilever Beams

    Science.gov (United States)

    Tejada, Arturo

    2009-01-01

    An important goal of NASA's Internal Vehicle Health Management program (IVHM) is to develop and verify methods and technologies for fault detection in critical airframe structures. A particularly promising new technology under development at NASA Langley Research Center is distributed Bragg fiber optic strain sensors. These sensors can be embedded in, for instance, aircraft wings to continuously monitor surface strain during flight. Strain information can then be used in conjunction with well-known vibrational techniques to detect faults due to changes in the wing's physical parameters or to the presence of incipient cracks. To verify the benefits of this technology, the Formal Methods Group at NASA LaRC has proposed the use of formal verification tools such as PVS. The verification process, however, requires knowledge of the physics and mathematics of the vibrational techniques and a clear understanding of the particular fault detection methodology. This report presents a succinct review of the physical principles behind the modeling of vibrating structures such as cantilever beams (the natural model of a wing). It also reviews two different classes of fault detection techniques and proposes a particular detection method for cracks in wings, which is amenable to formal verification. A prototype implementation of these methods using Matlab scripts is also described and is related to the fundamental theoretical concepts.

  11. Artificial neural network-based all-sky power estimation and fault detection in photovoltaic modules

    Science.gov (United States)

    Jazayeri, Kian; Jazayeri, Moein; Uysal, Sener

    2017-04-01

    The development of a system for output power estimation and fault detection in photovoltaic (PV) modules using an artificial neural network (ANN) is presented. Over 30,000 healthy and faulty data sets containing per-minute measurements of PV module output power (W) and irradiance (W/m2) along with real-time calculations of the Sun's position in the sky and the PV module surface temperature, collected during a three-month period, are fed to different ANNs as training paths. The first ANN being trained on healthy data is used for PV module output power estimation and the second ANN, which is trained on both healthy and faulty data, is utilized for PV module fault detection. The proposed PV module-level fault detection algorithm can expectedly be deployed in broader PV fleets by taking developmental considerations. The machine-learning-based automated system provides the possibility of all-sky real-time monitoring and fault detection of PV modules under any meteorological condition. Utilizing the proposed system, any power loss caused by damaged cells, shading conditions, accumulated dirt and dust on module surface, etc., is detected and reported immediately, potentially yielding increased reliability and efficiency of the PV systems and decreased support and maintenance costs.

  12. A Self-Learning Sensor Fault Detection Framework for Industry Monitoring IoT

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2013-01-01

    Full Text Available Many applications based on Internet of Things (IoT technology have recently founded in industry monitoring area. Thousands of sensors with different types work together in an industry monitoring system. Sensors at different locations can generate streaming data, which can be analyzed in the data center. In this paper, we propose a framework for online sensor fault detection. We motivate our technique in the context of the problem of the data value fault detection and event detection. We use the Statistics Sliding Windows (SSW to contain the recent sensor data and regress each window by Gaussian distribution. The regression result can be used to detect the data value fault. Devices on a production line may work in different workloads and the associate sensors will have different status. We divide the sensors into several status groups according to different part of production flow chat. In this way, the status of a sensor is associated with others in the same group. We fit the values in the Status Transform Window (STW to get the slope and generate a group trend vector. By comparing the current trend vector with history ones, we can detect a rational or irrational event. In order to determine parameters for each status group we build a self-learning worker thread in our framework which can edit the corresponding parameter according to the user feedback. Group-based fault detection (GbFD algorithm is proposed in this paper. We test the framework with a simulation dataset extracted from real data of an oil field. Test result shows that GbFD detects 95% sensor fault successfully.

  13. Principle and Control Design of Active Ground-Fault Arc Suppression Device for Full Compensation of Ground Current

    DEFF Research Database (Denmark)

    Wang, Wen; Zeng, Xiangjun; Yan, Lingjie

    2017-01-01

    . The commonly-used large-capacity reactive component may bring about overvoltage because of possible resonance with the distributed phase-to-ground capacitance. To solve these problems, an active ground-fault arc suppression device is presented. It employs a topology based on single-phase inverter to inject......Traditional ground-fault arc suppression devices mainly deal with capacitive component of ground current and have weak effect on the active and harmonic ones, which limits the arc suppression performance. The capacitive current detection needed in them suffers from low accuracy and robustness...... current into the neutral without any large-capacity reactors, and thus avoids the aforementioned overvoltage. It compensates all the active, reactive and harmonic components of the ground current to reliably extinguish the ground-fault arcs. A dual-loop voltage control method is proposed to realize arc...

  14. Fault diagnosis of downhole drilling incidents using adaptive observers and statistical change detection

    DEFF Research Database (Denmark)

    Willersrud, Anders; Blanke, Mogens; Imsland, Lars

    2015-01-01

    -Gaussian,t-distributednoise, and a dedicated multivariate statistical change detection approach isused that detects and isolates faults by detecting simultaneous changes inestimated parameters and ow rates. The properties of the multivariate di-agnosis method are analyzed, and it is shown how detection and false alarmprobabilities...... expectedfrom various defects, can be used to diagnose faults while in development.This paper shows how estimated friction parameters and ow rates can de-tect and isolate the type of incident, as well as isolating the position of adefect. Estimates are shown to be subjected to non...... are assessed and optimized using data-based learning to obtainthresholds for hypothesis testing. Data from a 1400 m horizontal ow loop isused to test the method, and successful diagnosis of the incidents drillstringwashout (pipe leakage), lost circulation, gas in ux, and drill bit plugging aredemonstrated....

  15. Detection and Modeling of High-Dimensional Thresholds for Fault Detection and Diagnosis

    Science.gov (United States)

    He, Yuning

    2015-01-01

    Many Fault Detection and Diagnosis (FDD) systems use discrete models for detection and reasoning. To obtain categorical values like oil pressure too high, analog sensor values need to be discretized using a suitablethreshold. Time series of analog and discrete sensor readings are processed and discretized as they come in. This task isusually performed by the wrapper code'' of the FDD system, together with signal preprocessing and filtering. In practice,selecting the right threshold is very difficult, because it heavily influences the quality of diagnosis. If a threshold causesthe alarm trigger even in nominal situations, false alarms will be the consequence. On the other hand, if threshold settingdoes not trigger in case of an off-nominal condition, important alarms might be missed, potentially causing hazardoussituations. In this paper, we will in detail describe the underlying statistical modeling techniques and algorithm as well as the Bayesian method for selecting the most likely shape and its parameters. Our approach will be illustrated by several examples from the Aerospace domain.

  16. Electromagnetic and acoustic bimodality for the detection and localization of electrical arc faults

    Science.gov (United States)

    Vasile, C.; Ioana, C.; Digulescu, A.; Candel, I.

    2016-12-01

    Electrical arc faults pose an important problem to electrical installations worldwide, be it production facilities or distribution systems. In this context, it is easy to assess the economic repercussions of such a fault, when power supply is cut off downstream of its location, while also realizing that an early detection of the on-site smaller scale faults would be of great benefit. This articles serves as a review of the current state-of-the-art work that has been carried out on the subject of detection and localization of electrical arc faults, by exploiting the bimodality of this phenomenon, which generates simultaneously electromagnetic and acoustic waves, propagating in a free space path. En experimental setup has been defined, to demonstrate principles stated in previous works by the authors, and signal processing methods have been used in order to determine the DTOA (difference-of-time-of-arrival) of the acoustic signals, which allows localization of the transient fault. In the end there is a discussion regarding the results and further works, which aims to validate this approach in more real-life applications.

  17. Smart Sensor for Online Detection of Multiple-Combined Faults in VSD-Fed Induction Motors

    Science.gov (United States)

    Garcia-Ramirez, Armando G.; Osornio-Rios, Roque A.; Granados-Lieberman, David; Garcia-Perez, Arturo; Romero-Troncoso, Rene J.

    2012-01-01

    Induction motors fed through variable speed drives (VSD) are widely used in different industrial processes. Nowadays, the industry demands the integration of smart sensors to improve the fault detection in order to reduce cost, maintenance and power consumption. Induction motors can develop one or more faults at the same time that can be produce severe damages. The combined fault identification in induction motors is a demanding task, but it has been rarely considered in spite of being a common situation, because it is difficult to identify two or more faults simultaneously. This work presents a smart sensor for online detection of simple and multiple-combined faults in induction motors fed through a VSD in a wide frequency range covering low frequencies from 3 Hz and high frequencies up to 60 Hz based on a primary sensor being a commercially available current clamp or a hall-effect sensor. The proposed smart sensor implements a methodology based on the fast Fourier transform (FFT), RMS calculation and artificial neural networks (ANN), which are processed online using digital hardware signal processing based on field programmable gate array (FPGA).

  18. An online tacholess order tracking technique based on generalized demodulation for rolling bearing fault detection

    Science.gov (United States)

    Wang, Yi; Xu, Guanghua; Luo, Ailing; Liang, Lin; Jiang, Kuosheng

    2016-04-01

    Vibration analysis has been proved to be an effective and powerful tool for the condition monitoring and fault diagnosis of rolling bearings. During the past decades, the conventional envelope analysis has been one of the main approaches in vibration signal processing. However, the envelope analysis is based on stationary assumption, thus it is not applicable to the fault diagnosis of bearings under rotating speed variation conditions. This constraint limits the bearing diagnosis in industrial applications. In recent years, order tracking methods based on time-frequency representation have been proposed for bearing fault detection under speed variation operating conditions. However, the methods are only applicable for offline bearing fault detection. Aiming at the shortcomings of the current tacholess order tracking techniques, an online tacholess order tracking method is proposed in this paper. The proposed method is on the basis of extracting the instantaneous tachometer information from the collected vibration signal itself continuously, and resampling the original signal with equal angle increment. The envelope order spectrum is used for bearing fault identification. The effectiveness of the proposed method has been validated by both simulated and experimental bearing vibration signals.

  19. Delineation of Urban Active Faults Using Multi-scale Gravity Analysis in Shenzhen, South China

    Science.gov (United States)

    Xu, C.; Liu, X.

    2015-12-01

    In fact, many cities in the world are established on the active faults. As the rapid urban development, thousands of large facilities, such as ultrahigh buildings, supersized bridges, railway, and so on, are built near or on the faults, which may change the balance of faults and induce urban earthquake. Therefore, it is significant to delineate effectively the faults for urban planning construction and social sustainable development. Due to dense buildings in urban area, the ordinary approaches to identify active faults, like geological survey, artificial seismic exploration and electromagnetic exploration, are not convenient to be carried out. Gravity, reflecting the mass distribution of the Earth's interior, provides a more efficient and convenient method to delineate urban faults. The present study is an attempt to propose a novel gravity method, multi-scale gravity analysis, for identifying urban active faults and determining their stability. Firstly, the gravity anomalies are decomposed by wavelet multi-scale analysis. Secondly, based on the decomposed gravity anomalies, the crust is layered and the multilayer horizontal tectonic stress is inverted. Lastly, the decomposed anomalies and the inverted horizontal tectonic stress are used to infer the distribution and stability of main active faults. For validating our method, a case study on active faults in Shenzhen City is processed. The results show that the distribution of decomposed gravity anomalies and multilayer horizontal tectonic stress are controlled significantly by the strike of the main faults and can be used to infer depths of the faults. The main faults in Shenzhen may range from 4km to 20km in the depth. Each layer of the crust is nearly equipressure since the horizontal tectonic stress has small amplitude. It indicates that the main faults in Shenzhen are relatively stable and have no serious impact on planning and construction of the city.

  20. Delineating active faults by using integrated geophysical data at northeastern part of Cairo, Egypt

    Directory of Open Access Journals (Sweden)

    Sultan Awad Sultan Araffa

    2012-06-01

    Full Text Available Geophysical techniques such as gravity, magnetic and seismology are perfect tools for detecting subsurface structures of local, regional as well as of global scales. The study of the earthquake records can be used for differentiating the active and non active fault elements. In the current study more than 2200 land magnetic stations have been measured by using two proton magnetometers. The data is corrected for diurnal variations and then reduced by IGRF. The corrected data have been interpreted by different techniques after filtering the data to separate shallow sources (basaltic sheet from the deep sources (basement complex. Both Euler deconvolution and 3-D magnetic modeling have been carried out. The results of our interpretation have indicated that the depth to the upper surface of basaltic sheet ranges from less than 10–600 m, depth to the lower surface ranges from 60 to 750 m while the thickness of the basaltic sheet varies from less than 10–450 m. Moreover, gravity measurements have been conducted at the 2200 stations using a CG-3 gravimeter. The measured values are corrected to construct a Bouguer anomaly map. The least squares technique is then applied for regional residual separation. The third order of least squares is found to be the most suitable to separate the residual anomalies from the regional one. The resultant third order residual gravity map is used to delineate the structural fault systems of different characteristic trends. The trends are a NW–SE trend parallel to that of Gulf of Suez, a NE–SW trend parallel to the Gulf of Aqaba and an E–W trend parallel to the trend of Mediterranean Sea. Taking seismological records into consideration, it is found that most of 24 earthquake events recorded in the study area are located on fault elements. This gives an indication that the delineated fault elements are active.

  1. Detection of Emerging Faults on Industrial Gas Turbines Using Extended Gaussian Mixture Models

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-01-01

    Full Text Available This paper extends traditional Gaussian mixture model (GMM techniques to provide recognition of operational states and detection of emerging faults for industrial systems. A variational Bayesian method allows a GMM to cluster with its mixture components to facilitate the extraction of steady-state operational behaviour; this is recognised as being a primary factor in reducing the susceptibility of alternative prognostic/diagnostic techniques, which would initiate false-alarms resulting from control set-point and load changes. Furthermore, a GMM with an outlier component is discussed and applied for direct novelty/fault detection. An advantage of the variational Bayesian method over traditional predefined thresholds is the extraction of steady-state data during both full- and part-load cases, and a primary advantage of the GMM with an outlier component is its applicability for novelty detection when there is a lack of prior knowledge of fault patterns. Results obtained from the real-time measurements on the operational industrial gas turbines have shown that the proposed technique provides integrated preprocessing, benchmarking, and novelty/fault detection methodology.

  2. Similarity ratio analysis for early stage fault detection with optical emission spectrometer in plasma etching process

    National Research Council Canada - National Science Library

    Yang, Jie; McArdle, Conor; Daniels, Stephen

    2014-01-01

    ...) in plasma etching processes using real-time Optical Emission Spectrometer (OES) data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch-rate faults in real-time during an etching process...

  3. Stator fault detection for multi-phase machines with multiple reference frames transformation

    DEFF Research Database (Denmark)

    Bianchini, Claudio; Fornasiero, Emanuele; Matzen, T.N.

    2009-01-01

    -circuit current. This paper defines a diagnostic index for stator fault detection based upon the combination of information from two different reference frames. Both analytical and simulation analysis are adopted to validate the new diagnostic index. The analytical results are currently being validated...

  4. Application of black-box models to HVAC systems for fault detection

    NARCIS (Netherlands)

    Peitsman, H.C.; Bakker, V.E.

    1996-01-01

    This paper describes the application of black-box models for fault detection and diagnosis (FDD) in heating, ventilat-ing, and air-conditioning (HVAC) systems. In this study, mul-tiple-input/single-output (MISO) ARX models and artificial neural network (ANN) models are used. The ARX models are

  5. Model-based fault detection for proton exchange membrane fuel cell ...

    African Journals Online (AJOL)

    In this paper, an intelligent model-based fault detection (FD) is developed for proton exchange membrane fuel cell (PEMFC) dynamic systems using an independent radial basis function (RBF) networks. The novelty is that this RBF networks is used to model the PEMFC dynamic systems and residuals are generated based ...

  6. Closed-loop fault detection for full-envelope flight vehicle with measurement delays

    Directory of Open Access Journals (Sweden)

    Wang Zhaolei

    2015-06-01

    Full Text Available A closed-loop fault detection problem is investigated for the full-envelope flight vehicle with measurement delays, where the flight dynamics are modeled as a switched system with delayed feedback signals. The mode-dependent observer-based fault detection filters and state estimation feedback controllers are derived by considering the delays’ impact on the control system and fault detection system simultaneously. Then, considering updating lags of the controllers/filters’ switching signals which are introduced by the delayed measurement of altitude and Mach number, an asynchronous H∞ analysis method is proposed and the system model is further augmented to be an asynchronously switched time-delay system. Also, the global stability and desired performance of the augmented system are guaranteed by combining the switched delay-dependent Lyapunov–Krasovskii functional method with the average dwell time method (ADT, and the delay-dependent existing conditions for the controllers and fault detection filters are obtained in the form of the linear matrix inequalities (LMIs. Finally, numerical example based on the hypersonic vehicles and highly maneuverable technology (HiMAT vehicle is given to demonstrate the merits of the proposed method.

  7. Karhunen Loeve Basis Used for Detection of Gearbox Faults in a Wind Turbine

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    provided to the control system. In this paper a Karhunen-Loeve basis approach is designed for detecting changes in frequency response from rotating parts like a gearbox. The potential of this method is shown by applying it to an established Wind Turbine FDI and FTC Benchmark model. These faults...

  8. Comparative analysis of neural network and regression based condition monitoring approaches for wind turbine fault detection

    DEFF Research Database (Denmark)

    Schlechtingen, Meik; Santos, Ilmar

    2011-01-01

    approach are applied to further real time series containing gearbox bearing damages and stator temperature anomalies.The comparison revealed all three models being capable of detecting incipient faults. However, they differ in the effort required for model development and the remaining operational time...

  9. Poster Abstract : Fault Detection in Wireless Sensor Networks: A Hybrid Approach

    NARCIS (Netherlands)

    Warriach, Ehsan; Nguyen, Tuan Anh; Aiello, Marco; Tel, Kenji

    2012-01-01

    Wireless Sensor Network (WSN) deployment experiences show that data collected is prone to be imprecise and faulty due to internal and external influences, such as battery drain, environmental interference, sensor aging. An early detection of such faults is necessary for the effective operation of

  10. Two Trees: Migrating Fault Trees to Decision Trees for Real Time Fault Detection on International Space Station

    Science.gov (United States)

    Lee, Charles; Alena, Richard L.; Robinson, Peter

    2004-01-01

    We started from ISS fault trees example to migrate to decision trees, presented a method to convert fault trees to decision trees. The method shows that the visualizations of root cause of fault are easier and the tree manipulating becomes more programmatic via available decision tree programs. The visualization of decision trees for the diagnostic shows a format of straight forward and easy understands. For ISS real time fault diagnostic, the status of the systems could be shown by mining the signals through the trees and see where it stops at. The other advantage to use decision trees is that the trees can learn the fault patterns and predict the future fault from the historic data. The learning is not only on the static data sets but also can be online, through accumulating the real time data sets, the decision trees can gain and store faults patterns in the trees and recognize them when they come.

  11. Active faults crossing trunk pipeline routes: some important steps to avoid the disaster

    Science.gov (United States)

    Besstrashnov, Vladimir; Strom, Alexander

    2010-05-01

    Trunk pipelines that pass through tectonically active areas connecting oil and gas reservoirs with terminals and refineries cross active faults that can produce large earthquakes. Besides strong motion affecting vast areas, these earthquakes are often associated with surface faulting that provides additional hazard to pipelines. To avoid significant economic losses and environmental pollution, pipelines should be designed to sustain both effects (shaking and direct rupturing) without pipe damage and spill. Special studies aimed to provide necessary input data for the designers should be performed in the course of engineering survey. However, our experience on conducting and review of such studies for several oil and gas trunk pipelines in Russia show urgent need of more strict definition of basic conceptions and approaches used for identification and localization of these potentially hazardous tectonic features. Identification of active faults (fault zones) considered as causative faults - sources of strong motion caused by seismic waves that affect dozens kilometers of pipeline route can be done by use of both direct and indirect evidence of Late Pleistocene - Holocene activity of faults and fault zones. Since strong motion parameters can be considered as constant within the near-field zone, which width in case of large earthquake is up to dozens kilometers, accuracy of active fault location is not so critical and ±1-2 km precision provided by use of indirect evidence is acceptable. In contrast, if one have to identify and characterize zones of potential surface rupturing that require special design of the endangered pipeline section, only direct evidence of such activity can provide reliable input data for crossing design with relevant accuracy of fault location, amount and direction of displacement. Only traces of surface faults displacing Late Pleistocene - Holocene sediments and/or geomorphic features are considered as direct evidence of fault activity. Just

  12. Application of fault detection techniques to spiral bevel gear fatigue data

    Science.gov (United States)

    Zakrajsek, James J.; Handschuh, Robert F.; Decker, Harry J.

    1994-01-01

    Results of applying a variety of gear fault detection techniques to experimental data is presented. A spiral bevel gear fatigue rig was used to initiate a naturally occurring fault and propagate the fault to a near catastrophic condition of the test gear pair. The spiral bevel gear fatigue test lasted a total of eighteen hours. At approximately five and a half hours into the test, the rig was stopped to inspect the gears for damage, at which time a small pit was identified on a tooth of the pinion. The test was then stopped an additional seven times throughout the rest of the test in order to observe and document the growth and propagation of the fault. The test was ended when a major portion of a pinion tooth broke off. A personal computer based diagnostic system was developed to obtain vibration data from the test rig, and to perform the on-line gear condition monitoring. A number of gear fault detection techniques, which use the signal average in both the time and frequency domain, were applied to the experimental data. Among the techniques investigated, two of the recently developed methods appeared to be the first to react to the start of tooth damage. These methods continued to react to the damage as the pitted area grew in size to cover approximately 75% of the face width of the pinion tooth. In addition, information gathered from one of the newer methods was found to be a good accumulative damage indicator. An unexpected result of the test showed that although the speed of the rig was held to within a band of six percent of the nominal speed, and the load within eighteen percent of nominal, the resulting speed and load variations substantially affected the performance of all of the gear fault detection techniques investigated.

  13. Operations management system advanced automation: Fault detection isolation and recovery prototyping

    Science.gov (United States)

    Hanson, Matt

    1990-01-01

    The purpose of this project is to address the global fault detection, isolation and recovery (FDIR) requirements for Operation's Management System (OMS) automation within the Space Station Freedom program. This shall be accomplished by developing a selected FDIR prototype for the Space Station Freedom distributed processing systems. The prototype shall be based on advanced automation methodologies in addition to traditional software methods to meet the requirements for automation. A secondary objective is to expand the scope of the prototyping to encompass multiple aspects of station-wide fault management (SWFM) as discussed in OMS requirements documentation.

  14. Fault Detection and Diagnosis of Railway Point Machines by Sound Analysis.

    Science.gov (United States)

    Lee, Jonguk; Choi, Heesu; Park, Daihee; Chung, Yongwha; Kim, Hee-Young; Yoon, Sukhan

    2016-04-16

    Railway point devices act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Point failure can significantly affect railway operations, with potentially disastrous consequences. Therefore, early detection of anomalies is critical for monitoring and managing the condition of rail infrastructure. We present a data mining solution that utilizes audio data to efficiently detect and diagnose faults in railway condition monitoring systems. The system enables extracting mel-frequency cepstrum coefficients (MFCCs) from audio data with reduced feature dimensions using attribute subset selection, and employs support vector machines (SVMs) for early detection and classification of anomalies. Experimental results show that the system enables cost-effective detection and diagnosis of faults using a cheap microphone, with accuracy exceeding 94.1% whether used alone or in combination with other known methods.

  15. Fault Detection and Diagnosis of Railway Point Machines by Sound Analysis

    Science.gov (United States)

    Lee, Jonguk; Choi, Heesu; Park, Daihee; Chung, Yongwha; Kim, Hee-Young; Yoon, Sukhan

    2016-01-01

    Railway point devices act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Point failure can significantly affect railway operations, with potentially disastrous consequences. Therefore, early detection of anomalies is critical for monitoring and managing the condition of rail infrastructure. We present a data mining solution that utilizes audio data to efficiently detect and diagnose faults in railway condition monitoring systems. The system enables extracting mel-frequency cepstrum coefficients (MFCCs) from audio data with reduced feature dimensions using attribute subset selection, and employs support vector machines (SVMs) for early detection and classification of anomalies. Experimental results show that the system enables cost-effective detection and diagnosis of faults using a cheap microphone, with accuracy exceeding 94.1% whether used alone or in combination with other known methods. PMID:27092509

  16. Dating Tectonic Activity on Mercury’s Large-Scale Lobate-Scarp Thrust Faults

    Science.gov (United States)

    Barlow, Nadine G.; E Banks, Maria

    2017-10-01

    Mercury’s widespread large-scale lobate-scarp thrust faults reveal that the planet’s tectonic history has been dominated by global contraction, primarily due to cooling of its interior. Constraining the timing and duration of this contraction provides key insight into Mercury’s thermal and geologic evolution. We combine two techniques to enhance the statistical validity of size-frequency distribution crater analyses and constrain timing of the 1) earliest and 2) most recent detectable activity on several of Mercury’s largest lobate-scarp thrust faults. We use the sizes of craters directly transected by or superposed on the edge of the scarp face to define a count area around the scarp, a method we call the Modified Buffered Crater Counting Technique (MBCCT). We developed the MBCCT to avoid the issue of a near-zero scarp width since feature widths are included in area calculations of the commonly used Buffered Crater Counting Technique (BCCT). Since only craters directly intersecting the scarp face edge conclusively show evidence of crosscutting relations, we increase the number of craters in our analysis (and reduce uncertainties) by using the morphologic degradation state (i.e. relative age) of these intersecting craters to classify other similarly degraded craters within the count area (i.e., those with the same relative age) as superposing or transected. The resulting crater counts are divided into two categories: transected craters constrain the earliest possible activity and superposed craters constrain the most recent detectable activity. Absolute ages are computed for each population using the Marchi et al. [2009] model production function. A test of the Blossom lobate scarp indicates the MBCCT gives statistically equivalent results to the BCCT. We find that all scarps in this study crosscut surfaces Tolstojan or older in age (>~3.7 Ga). The most recent detectable activity along lobate-scarp thrust faults ranges from Calorian to Kuiperian (~3.7 Ga to

  17. A robust fault detection method of rolling bearings using modulation signal bispectrum analysis

    OpenAIRE

    Tian, Xiange; Gu, Fengshou; Rehab, Ibrahim; Abdalla, Gaballa; Ball, Andrew

    2015-01-01

    Envelope analysis is a widely used method for bearing fault detection. To obtain high detection accuracy, it is critical to select an optimal narrowband for envelope demodulation. Fast Kurtogram is an effective method for optimal narrowband selection. However, fast Kurtogram is not sufficiently robust because it is very sensitive to random noise and large aperiodic impulses which normally exist in practical application. To achieve the purpose of denoising and frequency band optimization, this...

  18. A Method Based on Multi-Sensor Data Fusion for Fault Detection of Planetary Gearboxes

    Directory of Open Access Journals (Sweden)

    Detong Kong

    2012-02-01

    Full Text Available Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that for systems as complex as planetary gearboxes, multiple sensors mounted on different locations provide complementary information on the health condition of the systems. On this basis, a fault detection method based on multi-sensor data fusion is introduced in this paper. In this method, two features developed for planetary gearboxes are used to characterize the gear health conditions, and an adaptive neuro-fuzzy inference system (ANFIS is utilized to fuse all features from different sensors. In order to demonstrate the effectiveness of the proposed method, experiments are carried out on a planetary gearbox test rig, on which multiple accelerometers are mounted for data collection. The comparisons between the proposed method and the methods based on individual sensors show that the former achieves much higher accuracies in detecting planetary gearbox faults.

  19. Study on Immune Relevant Vector Machine Based Intelligent Fault Detection and Diagnosis Algorithm

    Directory of Open Access Journals (Sweden)

    Zhong-hua Miao

    2013-01-01

    Full Text Available An immune relevant vector machine (IRVM based intelligent classification method is proposed by combining the random real-valued negative selection (RRNS algorithm and the relevant vector machine (RVM algorithm. The method proposed is aimed to handle the training problem of missing or incomplete fault sampling data and is inspired by the “self/nonself” recognition principle in the artificial immune systems. The detectors, generated by the RRNS, are treated as the “nonself” training samples and used to train the RVM model together with the “self” training samples. After the training succeeds, the “nonself” detection model, which requires only the “self” training samples, is obtained for the fault detection and diagnosis. It provides a general way solving the problems of this type and can be applied for both fault detection and fault diagnosis. The standard Fisher's Iris flower dataset is used to experimentally testify the proposed method, and the results are compared with those from the support vector data description (SVDD method. Experimental results have shown the validity and practicability of the proposed method.

  20. Detection of Sensor Faults in Small Helicopter UAVs Using Observer/Kalman Filter Identification

    Directory of Open Access Journals (Sweden)

    Guillermo Heredia

    2011-01-01

    Full Text Available Reliability is a critical issue in navigation of unmanned aerial vehicles (UAVs since there is no human pilot that can react to any abnormal situation. Due to size and cost limitations, redundant sensor schemes and aeronautical-grade navigation sensors used in large aircrafts cannot be installed in small UAVs. Therefore, other approaches like analytical redundancy should be used to detect faults in navigation sensors and increase reliability. This paper presents a sensor fault detection and diagnosis system for small autonomous helicopters based on analytical redundancy. Fault detection is accomplished by evaluating any significant change in the behaviour of the vehicle with respect to the fault-free behaviour, which is estimated by using an observer. The observer is obtained from input-output experimental data with the Observer/Kalman Filter Identification (OKID method. The OKID method is able to identify the system and an observer with properties similar to a Kalman filter, directly from input-output experimental data. Results are similar to the Kalman filter, but, with the proposed method, there is no need to estimate neither system matrices nor sensor and process noise covariance matrices. The system has been tested with real helicopter flight data, and the results compared with other methods.

  1. A METHOD TO IMPROVE RELIABILITY OF GEARBOX FAULT DETECTION WITH ARTIFICIAL NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    P.V. Srihari

    2010-12-01

    Full Text Available Fault diagnosis of gearboxes plays an important role in increasing the availability of machinery in condition monitoring. An effort has been made in this work to develop an artificial neural networks (ANN based fault detection system to increase reliability. Two prominent fault conditions in gears, worn-out and broken teeth, are simulated and five feature parameters are extracted based on vibration signals which are used as input features to the ANN based fault detection system developed in MATLAB, a three layered feed forward network using a back propagation algorithm. This ANN system has been trained with 30 sets of data and tested with 10 sets of data. The learning rate and number of hidden layer neurons are varied individually and the optimal training parameters are found based on the number of epochs. Among the five different learning rates used the 0.15 is deduced to be optimal one and at that learning rate the number of hidden layer neurons of 9 was the optimal one out of the three values considered. Then keeping the training parameters fixed, the number of hidden layers is varied by comparing the performance of the networks and results show the two and three hidden layers have the best detection accuracy.

  2. A method based on multi-sensor data fusion for fault detection of planetary gearboxes.

    Science.gov (United States)

    Lei, Yaguo; Lin, Jing; He, Zhengjia; Kong, Detong

    2012-01-01

    Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that for systems as complex as planetary gearboxes, multiple sensors mounted on different locations provide complementary information on the health condition of the systems. On this basis, a fault detection method based on multi-sensor data fusion is introduced in this paper. In this method, two features developed for planetary gearboxes are used to characterize the gear health conditions, and an adaptive neuro-fuzzy inference system (ANFIS) is utilized to fuse all features from different sensors. In order to demonstrate the effectiveness of the proposed method, experiments are carried out on a planetary gearbox test rig, on which multiple accelerometers are mounted for data collection. The comparisons between the proposed method and the methods based on individual sensors show that the former achieves much higher accuracies in detecting planetary gearbox faults.

  3. Detecting eccentricity faults in a PMSM in non-stationary conditions

    Directory of Open Access Journals (Sweden)

    Javier Rosero García

    2012-01-01

    Full Text Available Permanent magnet alternating current machines are being widely used in applications demanding high and rugged performance, such as industrial automation and the aerospace and automotive industries. This paper presents a study of a permanent magnet synchronous machine (PMSM running in eccentricity; these machines’ condition monitoring and fault detection would provide added value and they are also assuming growing importance. This paper investigates the effect of eccentricity faults on PMSM motors’ current spectrum with a view to developing an effective condition-monitoring scheme using two-dimensional (2-D finite element analysis (FEA. Stator current induced harmonics were investigated for fault conditions and advanced signal analysis involved continuous and discrete wavelet transforms. Simulation and experimental results are presented to substantiate that the proposed method worked over a wide speed range for motor operation and that it provided an effective tool for diagnosing PMSM operating condition.

  4. Comparative Study of Parametric and Non-parametric Approaches in Fault Detection and Isolation

    DEFF Research Database (Denmark)

    Katebi, S.D.; Blanke, M.; Katebi, M.R.

    This report describes a comparative study between two approaches to fault detection and isolation in dynamic systems. The first approach uses a parametric model of the system. The main components of such techniques are residual and signature generation for processing and analyzing. The second...... algorithms employed are adopted from the template matching in pattern recognition. Extensive simulation studies are performed to demonstrate satisfactory performance of the proposed techniques. The advantages and disadvantages of each approach are discussed and analyzed....... approach is non-parametric in the sense that the signature analysis is only dependent on the frequency or time domain information extracted directly from the input-output signals. Based on these approaches, two different fault monitoring schemes are developed where the feature extraction and fault decision...

  5. Feature extraction using adaptive multiwavelets and synthetic detection index for rotor fault diagnosis of rotating machinery

    Science.gov (United States)

    Lu, Na; Xiao, Zhihuai; Malik, O. P.

    2015-02-01

    State identification to diagnose the condition of rotating machinery is often converted to a classification problem of values of non-dimensional symptom parameters (NSPs). To improve the sensitivity of the NSPs to the changes in machine condition, a novel feature extraction method based on adaptive multiwavelets and the synthetic detection index (SDI) is proposed in this paper. Based on the SDI maximization principle, optimal multiwavelets are searched by genetic algorithms (GAs) from an adaptive multiwavelets library and used for extracting fault features from vibration signals. By the optimal multiwavelets, more sensitive NSPs can be extracted. To examine the effectiveness of the optimal multiwavelets, conventional methods are used for comparison study. The obtained NSPs are fed into K-means classifier to diagnose rotor faults. The results show that the proposed method can effectively improve the sensitivity of the NSPs and achieve a higher discrimination rate for rotor fault diagnosis than the conventional methods.

  6. Detecting eccentricity faults in a PMSM in non-stationary conditions

    Directory of Open Access Journals (Sweden)

    Javier Rosero García

    2012-04-01

    Full Text Available Permanent magnet alternating current machines are being widely used in applications demanding high and rugged performance, such as industrial automation and the aerospace and automotive industries. This paper presents a study of a permanent magnet synchronous machine (PMSM running in eccentricity; these machines’ condition monitoring and fault detection would provide added value and they are also assuming growing importance. This paper investigates the effect of eccentricity faults on PMSM motors’ current spectrum with a view to developing an effective condition-monitoring scheme using two-dimensional (2-D finite element analysis (FEA. Stator current induced harmonics were investigated for fault conditions and advanced signal analysis involved continuous and discrete wavelet transforms. Simulation and experimental results are presented to substantiate that the proposed method worked over a wide speed range for motor operation and that it provided an effective tool for diagnosing PMSM operating condition.

  7. A Model-Based Probabilistic Inversion Framework for Wire Fault Detection Using TDR

    Science.gov (United States)

    Schuet, Stefan R.; Timucin, Dogan A.; Wheeler, Kevin R.

    2010-01-01

    Time-domain reflectometry (TDR) is one of the standard methods for diagnosing faults in electrical wiring and interconnect systems, with a long-standing history focused mainly on hardware development of both high-fidelity systems for laboratory use and portable hand-held devices for field deployment. While these devices can easily assess distance to hard faults such as sustained opens or shorts, their ability to assess subtle but important degradation such as chafing remains an open question. This paper presents a unified framework for TDR-based chafing fault detection in lossy coaxial cables by combining an S-parameter based forward modeling approach with a probabilistic (Bayesian) inference algorithm. Results are presented for the estimation of nominal and faulty cable parameters from laboratory data.

  8. A windowing and mapping strategy for gear tooth fault detection of a planetary gearbox

    Science.gov (United States)

    Liang, Xihui; Zuo, Ming J.; Liu, Libin

    2016-12-01

    When there is a single cracked tooth in a planet gear, the cracked tooth is enmeshed for very short time duration in comparison to the total time of a full revolution of the planet gear. The fault symptom generated by the single cracked tooth may be very weak. This study aims to develop a windowing and mapping strategy to interpret the vibration signal of a planetary gear at the tooth level. The fault symptoms generated by a single cracked tooth of the planet gear of interest can be extracted. The health condition of the planet gear can be assessed by comparing the differences among the signals of all teeth of the planet gear. The proposed windowing and mapping strategy is tested with both simulated vibration signals and experimental vibration signals. The tooth signals can be successfully decomposed and a single tooth fault on a planet gear can be effectively detected.

  9. Pinpoint core sampling at active faults in the Nankai subduction zone by new ROV "NSS"

    Science.gov (United States)

    Ashi, J.; Shirai, M.; Tokuyama, H.; Soh, W.; Kinoshita, M.; Machiyama, H.; Kanamatsu, T.; Hirono, T.; Ikehara, K.; Arai, K.; Omura, A.

    2004-12-01

    Piston coring across active faults in shallow water depth, as well as drilling or trenching of fault zone on land, provides us with information about earthquake timing, recurrence of fault activity and fault displacement. In contrast, it is not easy to take samples from deep-sea with pinpoint accuracy. In order to identify the position of the core sampler and approach the target for sampling, a transponder is recently installed on the cable just above the sampler. The pilot vehicle of new ROV "NSS" (Navigable Sampling System) can move by four thrusters, observe seafloor by video cameras, release samplers and measurement tools by command from a mother ship, and real time geophysical or geochemical monitoring through an armored cable. The whole system including winches is removal. The ship with large deck can be equipped with NSS system. Depth capability of the pilot vehicle is 4000m and maximum payload weight is 1.5 Tons. First cruise using NSS was conducted in the Nankai Trough and the Sagami Trough using JAMSTEC R/V "Kaiyo" in 2003. Piston cores were taken from active faults off the Central Japan in the Nankai Trough, and the cold seep sites along the blind fault off Hatsushima, Sagami Bay. NSS using seafloor video camera and thrusters has accuracy of pinpoint sampling within 2m, and allows us to take samples from narrow fault zone or small clam colony. Core samples derived from active fault zones show different sedimentation histories; lack of strata and differences of layer thickness across dip-slip faults and lithological changes with time across strike-slip faults near submarine canyon, and provide information about recurrence time and fault displacement. NSS is one of tools that break through difficulties of pinpoint sampling in deep-sea and will proceed studies of active submarine faults.

  10. Early (pre–8 Ma) fault activity and temporal strain accumulation in the central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Bull, J.M.; Scrutton, R.A.

    -reflection profiles within the central Indian Ocean demonstrate that compressional activity started much earlier than previously thought, at around 15.4-13.9 Ma. From reconstructions of fault activity histories, it is shown that 12% of the total reverse fault...

  11. Unusual fault detection and loss analysis in optical fiber connections with refractive index matching material

    Science.gov (United States)

    Kihara, Mitsuru; Nagano, Ryuichiro; Izumita, Hisashi; Toyonaga, Masanobu

    2012-05-01

    We investigated and analyzed an unusual fault that occurs in optical access fiber networks, which is caused by a defective fiber connection. We developed a fault-detection system to locate such a fault by using both optical power level and optical pulse measurement methods. We investigated a defective mechanical splice in three laboratory tests: outward appearance, non-destructive, and dismantled. As a result, we confirmed that the defective mechanical splice had large gaps of more than 10 μm. We also analyzed the unusual fault that occurs from such a defective mechanical splice in mechanically transferrable (MT) connector experiments. The experimental results revealed that the optical performance of fiber connections with a mixture of refractive index matching material and air-filled gaps was extremely unstable and varied widely. In the worst case, the insertion loss worsened to more than 30 dB. The case of the fault caused by a mixture of refractive index matching material and air-filled gaps between the ends of optical fibers is thought to occur independently of the sorts or structures of optical fiber connectors and could be a characteristic peculiar to optical fiber connections using refractive index matching material. These findings can be applied to optical fiber connections that use refractive index matching material, such as MT connectors in outside underground facilities, mechanical splices, or field assembly connectors at aerial and home sites in optical access networks. These findings also support the practical construction and operation of optical network systems.

  12. Detection of Static Eccentricity Fault in Saturated Induction Motors by ...

    African Journals Online (AJOL)

    Unfortunately, motor current signature analysis (MCSA) cannot detect the small degrees of the purely static eccentricity (SE) defects, while the air-gap magnetic flux signature analysis (FSA) is applied successfully. The simulation results are obtained by using time stepping finite elements (TSFE) method. In order to show the ...

  13. Lessons for active fault assessment learned from the destructive 2016 Kumamoto earthquakes in Japan

    Science.gov (United States)

    Suzuki, Y.; Watanabe, M.; Nakata, T.

    2016-12-01

    The 2016 Kumamoto earthquake composed of magnitude-6.5 foreshock on April 14th and 7.3 main shock struck on 16th was generated by a well-known the Futagawa-Hinagu active fault causing severe damage by strong ground motions as severe as JMA intensity 7 (equivalent to MMI 10-11) twice in the central part of Kyushu, Japan. Long-term earthquake prediction for this region from the Japanese government is more or less consistent with what happened, several problems were left for discussion on 1) segmentation of faults; 2) mechanism of strong ground motion; and 3) unexpected surface fault ruptures along unmapped active fault traces. The Futagawa-Hinagu fault was assessed in 2002 and 2013 by Japanese Government. In the 2002 evaluation, the fault was identified as a 100km-long fault, and divided into three segments based on geometry of active fault traces. On the other hand, the 2013 evaluation separated this fault system into two independent faults namely Futagawa fault and Hinagu fault based on additional date such as gravity and sub-surface geology. However, tectonic geomorphology emphasizes continuity of tectonic landforms along the faults, and does not support the evaluation done in 2013. The main shock attacked wider area including the strongly shaken area of the foreshock, and prominent surface fault ruptures only appeared with the main shock, while minor fractures recognized mainly on metaled roads in foreshock area, were reactivated by the main shock. From these data, we consider that foreshock and main shock were generated by activities of the same fault, suggesting that the 2002 evaluation is appropriate. According to this evaluation, the foreshock should be regarded as "one size smaller earthquake than that expected from the fault", and we should have noticed the possible successive occurrence of larger earthquake after the foreshock. It is often stated that strong ground motion occurs in any location; however, this understanding may be misleading. Narrow severe

  14. ABOUT THE WAVE MECHANISM OF ACTIVATION OF FAULTS IN SEISMIC ZONES OF THE LITHOSPHERE IN MONGOLIA

    Directory of Open Access Journals (Sweden)

    M. G. Mel’nikov

    2015-09-01

    Full Text Available The study is focused on earthquake migrations along active faults in seismic zones of Mongolia. The earthquake migrations are interpreted as a result of the influence of deformational waves. Vector velocities and other parameters of the deformational waves are studied. Based on data from largescale maps, local faults are compared, and differences and similarities of parameters of waves related to faults of different ranks are described.

  15. Numerical Simulation of Seismicity in Active-Fault System in the Japanese Island

    Science.gov (United States)

    Kuwahara, Y.; Cho, I.

    2016-12-01

    We have conducted numerical simulations of seismicity in an active-fault system in the Japanese island to investigate the effects of stress transfer interaction of large earthquakes. Sixty major active faults were embedded into a 3D realistic rheological structure model of the crust and mantle of the central part of the main island of Japan for FEM simulations. The rheological model has been constructed, considering geophysical and geological data (Cho & Kuwahara, 2013a, b). The model consists of two layers: an upper part is of the elastic layer with non-uniform thickness and a lower one is of a Maxwell viscoelastic layer with a uniform viscosity of 10E21Pas. Tectonic stress assumed in the simulations is a superposition of an E-W compressional stress to an entire body of the model and stresses caused by a collision of the Izu Peninsula to the main land of Japan. Active fault geometries, such as position, strike, dip, length and width, were given with reference to results of a fault evaluation by the Headquarters for Earthquake Research Promotion of the MEXT (a ministry of the Japanese government). We have also introduced a shear zone with 5-km thickness and viscous edge zones into the model as deep extension and both lateral edges of each active fault, respectively, with the same Maxwell viscoelastic properties as the lower layer of the structure model. Earthquake ruptures on the active faults were triggered on the occasion that a shear stress reached a presumed level on some monitoring points on the fault plane. Stresses on the monitoring points were a superposition of the tectonic stress above-mentioned and Green's functions beforehand calculated for the rheology structure model from the ruptured fault to the other faults. Thus, we can show the calculation results of return period of an earthquake cycle of each active fault and its fluctuation due to the stress perturbations from earthquakes on other active faults

  16. Geological conditions for lateral sealing of active faults and relevant research methods

    Directory of Open Access Journals (Sweden)

    Guang Fu

    2017-01-01

    Full Text Available Many researchers worked a lot on geologic conditions for lateral sealing of faults, but none of their studies took the effect of internal structures of fault zones on the lateral sealing capacity of faults. Therefore, the lateral sealing of active faults has rarely been discussed. In this paper, based on the analysis of the composition and structure characteristics of fault fillings, the geological conditions for lateral sealing of active faults and relevant research method were discussed in reference to the lateral sealing mechanisms of inactive fault rocks. It is shown that, in order to satisfy geologically the lateral sealing of active faults, the faults should be antithetic and the faulted strata should be mainly composed of mudstone, so that the displacement pressure of fault fillings is higher than or equal to that of reservoir rocks in oil and gas migration block. Then, a research method for the lateral sealing of active faults was established by comparing the displacement pressure of fillings in the fault with that of reservoir rocks in oil and gas migration block. This method was applied to three antithetic faults (F1, F2 and F3 in No. 1 structure of the Nanpu Sag, Bohai Bay Basin. As revealed, the fillings of these three active faults were mostly argillaceous at the stage of natural gas accumulation (the late stage of Neogene Minghuazhen Fm sedimentation, and their displacement pressures were higher than that of reservoir rocks in the first member of Paleogene Dongying Fm (F1 and F3 and the Neogene Guantao Fm (F2. Accordingly, they are laterally sealed for natural gas, which is conducive to the accumulation and preservation of natural gas. Industrial gas flow has been produced from the first member of Paleogene Dongying Fm in Well Np101, the Guantao Fm in Well Np1-2 and the first member of Paleogene Dongying Fm in Well Np1, which is in agreement with the analysis result. It is verified that this method is feasible for investigating the

  17. Multiple fault separation and detection by joint subspace learning for the health assessment of wind turbine gearboxes

    Science.gov (United States)

    Du, Zhaohui; Chen, Xuefeng; Zhang, Han; Zi, Yanyang; Yan, Ruqiang

    2017-09-01

    The gearbox of a wind turbine (WT) has dominant failure rates and highest downtime loss among all WT subsystems. Thus, gearbox health assessment for maintenance cost reduction is of paramount importance. The concurrence of multiple faults in gearbox components is a common phenomenon due to fault induction mechanism. This problem should be considered before planning to replace the components of the WT gearbox. Therefore, the key fault patterns should be reliably identified from noisy observation data for the development of an effective maintenance strategy. However, most of the existing studies focusing on multiple fault diagnosis always suffer from inappropriate division of fault information in order to satisfy various rigorous decomposition principles or statistical assumptions, such as the smooth envelope principle of ensemble empirical mode decomposition and the mutual independence assumption of independent component analysis. Thus, this paper presents a joint subspace learning-based multiple fault detection (JSL-MFD) technique to construct different subspaces adaptively for different fault patterns. Its main advantage is its capability to learn multiple fault subspaces directly from the observation signal itself. It can also sparsely concentrate the feature information into a few dominant subspace coefficients. Furthermore, it can eliminate noise by simply performing coefficient shrinkage operations. Consequently, multiple fault patterns are reliably identified by utilizing the maximum fault information criterion. The superiority of JSL-MFD in multiple fault separation and detection is comprehensively investigated and verified by the analysis of a data set of a 750 kW WT gearbox. Results show that JSL-MFD is superior to a state-of-the-art technique in detecting hidden fault patterns and enhancing detection accuracy.

  18. Active fault systems of the Kivu rift and Virunga volcanic province, and implications for geohazards

    Science.gov (United States)

    Zal, H. J.; Ebinger, C. J.; Wood, D. J.; Scholz, C. A.; d'Oreye, N.; Carn, S. A.; Rutagarama, U.

    2013-12-01

    H Zal, C Ebinger, D. Wood, C. Scholz, N. d'Oreye, S. Carn, U. Rutagarama The weakly magmatic Western rift system, East Africa, is marked by fault-bounded basins filled by freshwater lakes that record tectonic and climatic signals. One of the smallest of the African Great Lakes, Lake Kivu, represents a unique geohazard owing to the warm, saline bottom waters that are saturated in methane, as well as two of the most active volcanoes in Africa that effectively dam the northern end of the lake. Yet, the dynamics of the basin system and the role of magmatism were only loosely constrained prior to new field and laboratory studies in Rwanda. In this work, we curated, merged, and analyzed historical and digital data sets, including spectral analyses of merged Shuttle Radar Topography Mission topography and high resolution CHIRP bathymetry calibrated by previously mapped fault locations along the margins and beneath the lake. We quantitatively compare these fault maps with the time-space distribution of earthquakes located using data from a temporary array along the northern sector of Lake Kivu, as well as space-based geodetic data. During 2012, seismicity rates were highest beneath Nyiragongo volcano, where a range of low frequency (1-3 s peak frequency) to tectonic earthquakes were located. Swarms of low-frequency earthquakes correspond to periods of elevated gas emissions, as detected by Ozone Monitoring Instrument (OMI). Earthquake swarms also occur beneath Karisimbi and Nyamuragira volcanoes. A migrating swarm of earthquakes in May 2012 suggests a sill intrusion at the DR Congo-Rwanda border. We delineate two fault sets: SW-NE, and sub-N-S. Excluding the volcano-tectonic earthquakes, most of the earthquakes are located along subsurface projections of steep border faults, and intrabasinal faults calibrated by seismic reflection data. Small magnitude earthquakes also occur beneath the uplifted rift flanks. Time-space variations in seismicity patterns provide a baseline

  19. Linear Quadratic Controller with Fault Detection in Compact Disk Players

    DEFF Research Database (Denmark)

    Vidal, Enrique Sanchez; Hansen, K.G.; Andersen, R.S.

    2001-01-01

    The design of the positioning controllers in Optical Disk Drives are today subjected to a trade off between an acceptable suppression of external disturbances and an acceptable immunity against surfaces defects. In this paper an algorithm is suggested to detect defects of the disk surface combined...... with an observer and a Linear Quadratic Regulator. As a result, the mentioned trade off is minimized and the playability of the tested compact disk player is considerably enhanced....

  20. Active Faults, Modern Seismicity And Block Structure Of Eurasia

    Science.gov (United States)

    Gatinsky, Y.; Rundquist, D.

    2004-12-01

    The analysis of on active faults and seismicity shows that the only a northern part of Eurasia should be regarded as an indivisible lithosphere unit. We defined it as the North Eurasian plate (Gatinsky, Rundquist, 2004) unlike the Eurasian plate s.l., which can be used only for paleotectonic reconstructions. The North Eurasian plate is bordered by zones of seismic activity traced along the Gakkel ridge, the Chersky and Stanovoi ranges, the Baikal rift, Altai--Sayany region, northern Tien Shan, Pamir, Hindu Kush and Kopet Dagh, Great Caucasus, northern Anatolia, Rhodopes, Carpathians, eastern and central Alps. Relationships between this plate and Europe west of the Rhine grabens remain ambiguous. The satellite measurements for them seem to be similar (Nocquet, Calais, 2003), but structural and seismic evidences allow suggesting their incipient division. Wide zones between this plate and neighboring ones can be distinguished outside north Eurasia. These zones consist of numerous blocks of various sizes. Block boundaries are mainly characterized by the high seismicity and development of active wrench faults, thrusts or modern rifts. Some of such zones were named earlier as "diffuse plate boundaries" (Stein et al., 2002; Bird et al, 2003). We suggest to name them as "transit zones" because they are situated between large lithosphere plates and as if transfer the stress field of one of them to other. Blocks within the transit zones reveal local divergences in GPS vectors of their displacements in the ITRF system and especially with respect to fixed Eurasia. At the same time data of satellite measurements emphasize the unity of the North Eurasian plate, which moves eastward in absolute coordinates with some clockwise rotation. The stress distribution in inner parts of the continent is being affected by the interaction with different plates and blocks. It can be more effectively illustrated by a «triangle» of the maximal seismic activity of Eurasia in the central Asia

  1. E-core transverse flux machine with integrated fault detection system

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Runólfsson, Gunnar; Thorsdóttir, Thórunn Ágústa

    2011-01-01

    extent also thermal. Since the E-core transverse flux-machine belongs to the family of the SRMs it has unique properties of intervals without current in the windings. By careful investigation of the voltage and current in these intervals a very simple method to detect single and partial turn short......The E-core transverse flux machine, which is a variation of the classical Switched Reluctance machine (SRM), have all the basic properties to be considered as a very fault tolerant machine. Every single coil in the machine is isolated from the each others both magnetic, electrical and to some...... circuit faults have been developed. For other types of machines the single and partial turn short circuit is very difficult to deal with and requires normally very comprehensive detection and calculation schemes. The developed detection algorithm combined with the E-core transverse flux machine...

  2. A measurement-based fault detection approach applied to monitor robots swarm

    KAUST Repository

    Khaldi, Belkacem

    2017-07-10

    Swarm robotics requires continuous monitoring to detect abnormal events and to sustain normal operations. Indeed, swarm robotics with one or more faulty robots leads to degradation of performances complying with the target requirements. This paper present an innovative data-driven fault detection method for monitoring robots swarm. The method combines the flexibility of principal component analysis (PCA) models and the greater sensitivity of the exponentially-weighted moving average control chart to incipient changes. We illustrate through simulated data collected from the ARGoS simulator that a significant improvement in fault detection can be obtained by using the proposed methods as compared to the use of the conventional PCA-based methods.

  3. Monitoring a robot swarm using a data-driven fault detection approach

    KAUST Repository

    Khaldi, Belkacem

    2017-06-30

    Using swarm robotics system, with one or more faulty robots, to accomplish specific tasks may lead to degradation in performances complying with the target requirements. In such circumstances, robot swarms require continuous monitoring to detect abnormal events and to sustain normal operations. In this paper, an innovative exogenous fault detection method for monitoring robots swarm is presented. The method merges the flexibility of principal component analysis (PCA) models and the greater sensitivity of the exponentially-weighted moving average (EWMA) and cumulative sum (CUSUM) control charts to insidious changes. The method is tested and evaluated on a swarm of simulated foot-bot robots performing a circle formation task, via the viscoelastic control model. We illustrate through simulated data collected from the ARGoS simulator that a significant improvement in fault detection can be obtained by using the proposed method where compared to the conventional PCA-based methods (i.e., T2 and Q).

  4. Fault Detection for Non-Gaussian Stochastic Systems with Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Tao Li

    2013-01-01

    Full Text Available Fault detection (FD for non-Gaussian stochastic systems with time-varying delay is studied. The available information for the addressed problem is the input and the measured output probability density functions (PDFs of the system. In this framework, firstly, by constructing an augmented Lyapunov functional, which involves some slack variables and a tuning parameter, a delay-dependent condition for the existence of FD observer is derived in terms of linear matrix inequality (LMI and the fault can be detected through a threshold. Secondly, in order to improve the detection sensitivity performance, the optimal algorithm is applied to minimize the threshold value. Finally, paper-making process example is given to demonstrate the applicability of the proposed approach.

  5. Frequency based Wind Turbine Gearbox Fault Detection applied to a 750 kW Wind Turbine

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Nejad, Amir R.

    2014-01-01

    turbines. One of the critical components in modern wind turbines is the gearbox. Failures in the gearbox are costly both due to the cost of the gearbox itself, but also due to lost power generation during repair of it. Wind turbine gearboxes are consequently monitored by condition monitoring systems...... operating in parallel with the control system, and also uses additional sensors measuring different accelerations and noises, etc. In this paper gearbox data from high fidelity gearbox model of a 750 kW wind turbine gearbox, simulated with and without faults are used to shown the potential of frequency...... based detection schemes applied on measurements normally available in a wind controller system. This paper shows that two given faults in the gearbox can be detected using a frequency based detection approach applied to sensor signals normally available in the wind turbine control system. This means...

  6. Vibration-Based Adaptive Novelty Detection Method for Monitoring Faults in a Kinematic Chain

    Directory of Open Access Journals (Sweden)

    Jesus Adolfo Cariño-Corrales

    2016-01-01

    Full Text Available This paper presents an adaptive novelty detection methodology applied to a kinematic chain for the monitoring of faults. The proposed approach has the premise that only information of the healthy operation of the machine is initially available and fault scenarios will eventually develop. This approach aims to cover some of the challenges presented when condition monitoring is applied under a continuous learning framework. The structure of the method is divided into two recursive stages: first, an offline stage for initialization and retraining of the feature reduction and novelty detection modules and, second, an online monitoring stage to continuously assess the condition of the machine. Contrary to classical static feature reduction approaches, the proposed method reformulates the features by employing first a Laplacian Score ranking and then the Fisher Score ranking for retraining. The proposed methodology is validated experimentally by monitoring the vibration measurements of a kinematic chain driven by an induction motor. Two faults are induced in the motor to validate the method performance to detect anomalies and adapt the feature reduction and novelty detection modules to the new information. The obtained results show the advantages of employing an adaptive approach for novelty detection and feature reduction making the proposed method suitable for industrial machinery diagnosis applications.

  7. Evidence for propagating, active tensional faulting in Upper Kåfjord valley, Troms County, Norway

    Science.gov (United States)

    Redfield, T. F.; Osmundsen, P. T.; Henderson, I. H. C.; Hermanns, R. L.

    2010-05-01

    New concepts governing margin extension and post-rift passive margin evolution are appearing from onshore and offshore studies. In Norway topographic escarpments, creation, preservation and destruction of landforms, and drainage patterns are related to structural templates created during the Jurassic rift phase. Contradicting the notion that post-rift isostatic compensation, thermal subsidence, and topographic degradation mark a passive margin's final evolutionary phases, we present geological evidence for currently-active tensional deformation, accommodated by release faulting, in uppermost Kåfjordalen and Signaldalen. In Signaldalen, propagation of the deformation tip has introduced active normal faulting to Finland. Ground observations indicate a large normal fault defines the eastern border of the Lyngen 'Alps' peninsula. There, a series of exceptionally well-preserved triangular facets adorn a sharp, elevated escarpment. To the east a swarm of small NE-trending normal faults are exposed in roadside outcrops near the mouth of Kåfjord, dipping both to the NW and SE. Displacement across the fault swarm is asymmetric, the greatest component of motion being down-to-the-NW in the direction of the Lyngen Fault. Another set of NE trending, NW dipping faults crop out at Revsdalfjellet. We interpret these faults to reflect splays to the Lyngen Fault. The hanging wall of the Lyngen Fault is characterized by numerous clusters of fault-controlled rockslides. We interpret the valleys of Signaldalen, Skibotndalen, and Kåfjordalen, located in the hanging wall of the Lyngen Fault, to have formed at least partly under the influence of release faults that accommodated hanging wall flexure and failure. Other fault scarps, trending more NW-SE, crop out at two Kåfjord rockslide sites, Nomandalstinden and Litledalen. Mineralized surfaces exhibiting dip-slip slickenlines indicate most of these faults are true tectonic features, not simply gravitationally-driven 'sackung' planes

  8. A NOVEL TECHNIQUE FOR MULTIPLE FAULTS AND THEIR LOCATIONS DETECTION AND START ELECTRODE SELECTION IN MICROFLUIDIC DIGITAL BIOCHIP

    Directory of Open Access Journals (Sweden)

    MUKTA MAJUMDER

    2013-10-01

    Full Text Available A device, that is used for biomedical operation or safety-critical applications like point-of-care health assessment, massive parallel DNA analysis, automated drug discovery, air-quality monitoring and food-safety testing, must have the attributes like reliability, dependability and correctness. As the biochips are used for these purposes; therefore, these devices must be fault free all the time. Naturally before using these chips, they must be well tested. We are proposing a novel technique that can detect multiple faults, locate the fault positions within the biochip, as well as calculate the traversal time if the biochip is fault free. The proposed technique also highlights a new idea how to select the appropriate base node or pseudo source (start electrode. The main idea of the proposed technique is to form multiple loops with the neighboring electrode arrays and then test each loop by traversing test droplet to check whether there is any fault. If a fault is detected then the proposed technique also locates it by backtracking the test droplet. In case, no fault is detected, the biochip is fault free then the proposed technique also calculates the time to traverse the chip. The result suggests that the proposed technique is efficient and shows significant improvement to calculate fault-free biochip traversal time over existing method.

  9. A method for detection and location of high resistance earth faults

    Energy Technology Data Exchange (ETDEWEB)

    Haenninen, S.; Lehtonen, M. [VTT Energy, Espoo (Finland); Antila, E. [ABB Transmit Oy (Finland)

    1998-08-01

    In the first part of this presentation, the theory of earth faults in unearthed and compensated power systems is briefly presented. The main factors affecting the high resistance fault detection are outlined and common practices for earth fault protection in present systems are summarized. The algorithms of the new method for high resistance fault detection and location are then presented. These are based on the change of neutral voltage and zero sequence currents, measured at the high voltage / medium voltage substation and also at the distribution line locations. The performance of the method is analyzed, and the possible error sources discussed. Among these are, for instance, switching actions, thunder storms and heavy snow fall. The feasibility of the method is then verified by an analysis based both on simulated data, which was derived using an EMTP-ATP simulator, and by real system data recorded during field tests at three substations. For the error source analysis, some real case data recorded during natural power system events, is also used

  10. Minimum System Sensitivity Study of Linear Discrete Time Systems for Fault Detection

    Directory of Open Access Journals (Sweden)

    Xiaobo Li

    2013-01-01

    Full Text Available Fault detection is a critical step in the fault diagnosis of modern complex systems. An important notion in fault detection is the smallest gain of system sensitivity, denoted as ℋ− index, which measures the worst fault sensitivity. This paper is concerned with characterizing ℋ− index for linear discrete time systems. First, a necessary and sufficient condition on the lower bound of ℋ− index in finite time horizon for linear discrete time-varying systems is developed. It is characterized in terms of the existence of solution to a backward difference Riccati equation with an inequality constraint. The result is further extended to systems with unknown initial condition based on a modified ℋ− index. In addition, for linear time-invariant systems in infinite time horizon, based on the definition of the ℋ− index in frequency domain, a condition in terms of algebraic Riccati equation is developed. In comparison with the well-known bounded real lemma, it is found that ℋ− index is not completely dual to ℋ∞ norm. Finally, several numerical examples are given to illustrate the main results.

  11. Simultaneous State and Parameter Estimation Based Actuator Fault Detection and Diagnosis for an Unmanned Helicopter

    Directory of Open Access Journals (Sweden)

    Wu Chong

    2015-03-01

    Full Text Available Simultaneous state and parameter estimation based actuator fault detection and diagnosis (FDD for single-rotor unmanned helicopters (UHs is investigated in this paper. A literature review of actuator FDD for UHs is given firstly. Based on actuator healthy coefficients (AHCs, which are introduced to represent actuator faults, a combined dynamic model is established with the augmented state containing both the flight state and AHCs. Then the actuator fault detection and diagnosis problem is transformed into a general nonlinear estimation one: given control inputs and the measured flight state contaminated by measurement noises, estimate both the flight state and AHCs recursively in each time-step, which is also known as the simultaneous state and parameter estimation problem. The estimated AHCs can further be used for fault tolerant control (FTC. Based on the existing widely used nonlinear estimation methods such as the unscented Kalman filter (UKF and the extended set-membership filter (ESMF, three kinds of adaptive schemes (KF-UKF, MIT-UKF and MIT-ESMF are proposed by our team to improve the actuator FDD performance. A comprehensive comparative study on these different estimation methods is given in detail to illustrate their advantages and disadvantages when applied to unmanned helicopter actuator FDD.

  12. Combination of geophysical methods for fault detection: a case study from the Møre-Trøndelag Fault Complex, Mid-Norway

    Science.gov (United States)

    Nasuti, A.; Dalsegg, E.; Ebbing, J.; Lundberg, E.; Tonnesen, J.; Pascal, C.

    2009-12-01

    The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault complexes in Scandinavia and perhaps on Earth. The MTFC appears to have controlled the tectonic evolution of central Norway and its shelf for the past 400 Myr, at least, and has experienced repeated reactivation during Paleozoic (Devonian to Permian), Mesozoic (Jurassic) and Cenozoic times. Despite its pronounced signature in the landscape its deep structure has remained unresolved until now. We acquired multiple geophysical data sets across a segment of the MTFC composed of two main faults (i.e. the Tjellefjorden and Fannefjorden faults). The faults are partly exposed and their respective traces can be seen as prominent topographic escarpments. However their exact locations (i.e. below Quaternary sediments), extents and dips are less clear, and have not been studied systematically by geophysical methods. To detect the fault zones and their structural attributes, a series of magnetic, resistivity, shallow refraction and deep reflection seismics profiles were measured across these fault zones. In addition, 265 new gravity points have been established in a region of 4x4 km. Interpretation of the magnetic data shows the distinctive signature of near-vertical faults (~80°-85° towards the south), trending NNE-SSW. Quantitative interpretation of the data points to a width of 90 to 150 m for the Tjellefjorden Fault and 200 to 400 m for the Fannefjorden Fault. Inversion of 2D resistivity data reveals a three-layered subsurface until 130 m depth. The layers represent the thin low resistive topsoil underlain by weathered bedrock, and the resistive bedrock. Within the resistive bedrock distinct low resistivity zones can be observed, which can be associated with highly fractured bedrock. These low resistive zones correlate to low velocity zones in the shallow refraction profile. The aim of using deep reflection seismic was to image structures in the upper crust down to a depth of 4 km. Processing of

  13. Evaluation of MEMS-Based Wireless Accelerometer Sensors in Detecting Gear Tooth Faults in Helicopter Transmissions

    Science.gov (United States)

    Lewicki, David George; Lambert, Nicholas A.; Wagoner, Robert S.

    2015-01-01

    The diagnostics capability of micro-electro-mechanical systems (MEMS) based rotating accelerometer sensors in detecting gear tooth crack failures in helicopter main-rotor transmissions was evaluated. MEMS sensors were installed on a pre-notched OH-58C spiral-bevel pinion gear. Endurance tests were performed and the gear was run to tooth fracture failure. Results from the MEMS sensor were compared to conventional accelerometers mounted on the transmission housing. Most of the four stationary accelerometers mounted on the gear box housing and most of the CI's used gave indications of failure at the end of the test. The MEMS system performed well and lasted the entire test. All MEMS accelerometers gave an indication of failure at the end of the test. The MEMS systems performed as well, if not better, than the stationary accelerometers mounted on the gear box housing with regards to gear tooth fault detection. For both the MEMS sensors and stationary sensors, the fault detection time was not much sooner than the actual tooth fracture time. The MEMS sensor spectrum data showed large first order shaft frequency sidebands due to the measurement rotating frame of reference. The method of constructing a pseudo tach signal from periodic characteristics of the vibration data was successful in deriving a TSA signal without an actual tach and proved as an effective way to improve fault detection for the MEMS.

  14. Determination of paleoseismic activity over a large time-scale: Fault scarp dating with 36Cl

    Science.gov (United States)

    Mozafari Amiri, Nasim; Tikhomirov, Dmitry; Sümer, Ökmen; Özkaymak, Çaǧlar; Uzel, Bora; Ivy-Ochs, Susan; Vockenhuber, Christof; Sözbilir, Hasan; Akçar, Naki

    2016-04-01

    Bedrock fault scarps are the most direct evidence of past earthquakes to reconstruct seismic activity in a large time-scale using cosmogenic 36Cl dating if built in carbonates. For this method, a surface along the fault scarp with a minimum amount of erosion is required to be chosen as an ideal target point. The section of the fault selected for sampling should cover at least two meters of the fault surface from the lower part of the scarp, where intersects with colluvium wedge. Ideally, sampling should be performed on a continuous strip along the direction of the fault slip direction. First, samples of 10 cm high and 15 cm wide are marked on the fault surface. Then, they are collected using cutters, hammer and chisel in a thickness of 3 cm. The main geometrical factors of scarp dip, scarp height, top surface dip and colluvium dip are also measured. Topographic shielding in the sampling spot is important to be estimated as well. Moreover, density of the fault scarp and colluvium are calculated. The physical and chemical preparations are carried in laboratory for AMS and chemical analysis of the samples. A Matlab® code is used for modelling of seismically active periods based on increasing production rate of 36Cl following each rupture, when a buried section of a fault is exposed. Therefore, by measuring the amount of cosmogenic 36Cl versus height, the timing of major ruptures and their offsets are determined. In our study, Manastır, Mugırtepe and Rahmiye faults in Gediz graben, Priene-Sazlı, Kalafat and Yavansu faults in Büyük Menderes graben and Ören fault in Gökava half-graben have been examined in the seismically active region of Western Turkey. Our results reconstruct at least five periods of high seismic activity during the Holocene time, three of which reveal seismic ruptures beyond the historical pre-existing data.

  15. Robust fault detection and isolation technique for single-input/single-output closed-loop control systems that exhibit actuator and sensor faults

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Alavi, S. M. Mahdi; Hayes, M. J.

    2008-01-01

    ) a graphical environment is provided for the design of fault detection (FD) filter, which is intuitively appealing from an engineering perspective. The FD filter can easily be obtained by manually shaping the frequency response into the complex plane. The question of interaction between actuator and sensor......An integrated quantitative feedback design and frequency-based fault detection and isolation (FDI) approach is presented for single-input/single-output systems. A novel design methodology, based on shaping the system frequency response, is proposed to generate an appropriate residual signal...... that is sensitive to actuator and sensor faults in the presence of model uncertainty and exogenous unknown (unmeasured) disturbances. The key features of this technique are: (1) the uncertain phase information is fully addressed by the design equations, resulting in a minimally conservative over-design and (2...

  16. Investigation on active faulting at the eastern border fault system of the Upper Rhine Graben using geophysical methods

    Science.gov (United States)

    Thomas, Jessica; Hürtgen, Jochen; Baize, Stéphane; Marc, Cushing Edward; Hervé, Jomard; Reicherter, Klaus

    2017-04-01

    The Upper Rhine Graben (URG) belongs to the European Cenozoic Rift System (ECRIS) and is one of the most tectonically active regions in Europe. It is delimited by NNW-SSE striking Tertiary-age normal faults to both sides, which are supposed to be active especially at the eastern side. The main goal of this study is the analysis of the activity of this eastern boarder fault system and the characterization of seismotectonic parameters to improve the seismotectonic models, which use faults in the calculation of seismic hazard assessment and are based on a very sparse data set at the moment. In the frame of a pre-trenching survey, geophysical measurements with electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were conducted in the area south of Freiburg im Breisgau, in order to define an appropriate trenching site to determine key fault parameters, such as magnitude, age of last events, slip rate and return periods. In the frame of the study, several potentially fault-related structures were found in the GPR and ERT profiles. The ERT proofed very useful for the revision and verification of features found in GPR profiles. The GPR has limitations in case of high soil water content and there is a tradeoff between achievable spatial resolution and investigation depth. Several faults described in former studies (e.g. geological map of Baden-Württemberg, GeORG (LGRB, 2012) and Nivière et al., 2008) could be verified, but partially with deviations in the exact location, possibly related to accuracy and density of the data sets, as well as the geophysical methods and interpolation methods employed. The URG is a low-strain setting with high recurrence intervals of earthquakes and high erosional rates due to the moderate climate of the URG and the erosional power of the Rhine-River. In addition, the subsurface is modified by intensive agricultural use, which makes the analysis of the geophysical sections difficult and sometimes ambiguous. For the

  17. A case study of sample entropy analysis to the fault detection of bearing in wind turbine

    Directory of Open Access Journals (Sweden)

    Qing Ni

    2017-10-01

    Full Text Available Rolling bearing is an important and fragile component in the wind turbine transmission system. The failure of rolling bearing is one of the highest risk events which may result in unexpected economic loss. To give a proper condition assessment of rolling bearing, especially for early fault detection, is of great importance and become an urgent issue to the wind energy industry. In this paper, sample entropy is studied through the field data of wind turbine transmission system measured from Lu Nan Wind Farm in China. Compared with several frequently used statistical indicators, sample entropy features advantages in detecting and evaluating the progress of the early faults of the rolling bearing. The studies show that the sample entropy is an effective and practical tool for condition monitoring of rolling bearing for a wind turbine transmission system.

  18. Fault Detection of Aircraft System with Random Forest Algorithm and Similarity Measure

    Directory of Open Access Journals (Sweden)

    Sanghyuk Lee

    2014-01-01

    Full Text Available Research on fault detection algorithm was developed with the similarity measure and random forest algorithm. The organized algorithm was applied to unmanned aircraft vehicle (UAV that was readied by us. Similarity measure was designed by the help of distance information, and its usefulness was also verified by proof. Fault decision was carried out by calculation of weighted similarity measure. Twelve available coefficients among healthy and faulty status data group were used to determine the decision. Similarity measure weighting was done and obtained through random forest algorithm (RFA; RF provides data priority. In order to get a fast response of decision, a limited number of coefficients was also considered. Relation of detection rate and amount of feature data were analyzed and illustrated. By repeated trial of similarity calculation, useful data amount was obtained.

  19. Active Fault Diagnosis and Assessment for Aircraft Health Management Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA LaRC need for innovative methods and tools for the diagnosis of aircraft faults and failures, Physical Optics Corporation (POC) proposes to...

  20. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2015-01-01

    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  1. Fault detection and isolation of PEM fuel cell system based on nonlinear analytical redundancy

    OpenAIRE

    Aitouche, A; Yang, Q; Ould Bouamama, B.

    2011-01-01

    Abstract This paper presents a procedure dealing with the issue of fault detection and isolation (FDI) using nonlinear analytical redundancy (NLAR) technique applied in a proton exchange membrane (PEM) fuel cell system based on its mathematic model. The model is proposed and simplified into a five orders state space representation. The transient phenomena captured in the model include the compressor dynamics, the flow characteristics, mass and energy conservation and manifold fluid...

  2. Effects of Channel Modification on Detection and Dating of Fault Scarps

    Science.gov (United States)

    Sare, R.; Hilley, G. E.

    2016-12-01

    Template matching of scarp-like features could potentially generate morphologic age estimates for individual scarps over entire regions, but data noise and scarp modification limits detection of fault scarps by this method. Template functions based on diffusion in the cross-scarp direction may fail to accurately date scarps near channel boundaries. Where channels reduce scarp amplitudes, or where cross-scarp noise is significant, signal-to-noise ratios decrease and the scarp may be poorly resolved. In this contribution, we explore the bias in morphologic age of a complex scarp produced by systematic changes in fault scarp curvature. For example, fault scarps may be modified by encroaching channel banks and mass failure, lateral diffusion of material into a channel, or undercutting parallel to the base of a scarp. We quantify such biases on morphologic age estimates using a block offset model subject to two-dimensional linear diffusion. We carry out a synthetic study of the effects of two-dimensional transport on morphologic age calculated using a profile model, and compare these results to a well- studied and constrained site along the San Andreas Fault at Wallace Creek, CA. This study serves as a first step towards defining regions of high confidence in template matching results based on scarp length, channel geometry, and near-scarp topography.

  3. VIBRATION ANALYSIS FOR DETECTION AND LOCALIZATION THE FAULTS OF ROTATING MACHINERY USING WAVELET TECHINIQUES

    Directory of Open Access Journals (Sweden)

    MIHAIL PRICOP

    2016-06-01

    Full Text Available Vulnerable and critical mechanical systems are bearings and drive belts. Signal analysis of vibration highlights the changes in root mean square, the frequency spectrum (frequencies and amplitudes in the time- frequency (Short Time Fourier Transform and Wavelet Transform, are the most used method for faults diagnosis and location of rotating machinery. This article presents the results of an experimental study applied on a di agnostic platform of rotating machinery through three Wavelet methods: (Discrete Wavelet Transform -DWT, Continuous Wavelet Transform -CWT, Wavelet Packet Transform -WPT with different mother wavelet. Wavelet Transform is used to decompose the original sig nal into sub -frequency band signals in order to obtain multiple data series at different resolutions and to identify faults appearing in the complex rotation systems. This paper investigates the use of different mother wavelet functions for drive belts and bearing fault diagnosis. The results demonstrate the possibility of using different mother wavelets in rotary systems diagnosis detecting and locating in this way the faults in bearings and drive belts.

  4. DETECTION OF FAULT LOCATION ON THE POWER LINES 6–35 kV WITH UNILATERAL FEED

    Directory of Open Access Journals (Sweden)

    F. A. Romaniuk

    2014-01-01

    Full Text Available The paper describes new algorithm of detecting the fault location for the power lines 6–35 kV with unilateral feed. The results of operational control of the short-circuit current for the faulted phases are the only initial data needed for the fault location algorithm. Analysis of the impact of the type of short circuit, transition resistance at the damaged point, errors of current transformers, load of the line, power and resistance of supply system, calculation errors of short-circuit currents at the beginning and at the end of the line on the performance of this algorithm is also performed. Estimated parameters of the algorithm of detecting the fault location based on identified influencing factors were established by method of computational experiment. Analysis of the simulation results performed shows that the variation of the relative error in the fault location determination for different types of faults is about the same. Moreover levels of these relative errors from the effects of all influencing factors can be less than just from one of them. This is due to the mutual compensation of the various factors’ influence on values of relative errors. This fact must be taken into consideration when performing the corresponding estimates for the worst case scenario.This paper presents the dynamic characteristics of this algorithm for detecting the fault location that allows estimating the time of detecting the fault location in different modes. Their analysis shows that there is almost no difference in quantitative and qualitative dependencies for different loads and types of faults. As the evaluation of results performed it should be noted that by means of the control only one parameter in short current mode, i.e. the short-circuit current, it is possibly with acceptable accuracy to detect the fault location. 

  5. Fault Diagnosis of Internal Combustion Engine Valve Clearance Using the Impact Commencement Detection Method.

    Science.gov (United States)

    Jiang, Zhinong; Mao, Zhiwei; Wang, Zijia; Zhang, Jinjie

    2017-12-15

    Internal combustion engines (ICEs) are widely used in many important fields. The valve train clearance of an ICE usually exceeds the normal value due to wear or faulty adjustment. This work aims at diagnosing the valve clearance fault based on the vibration signals measured on the engine cylinder heads. The non-stationarity of the ICE operating condition makes it difficult to obtain the nominal baseline, which is always an awkward problem for fault diagnosis. This paper overcomes the problem by inspecting the timing of valve closing impacts, of which the referenced baseline can be obtained by referencing design parameters rather than extraction during healthy conditions. To accurately detect the timing of valve closing impact from vibration signals, we carry out a new method to detect and extract the commencement of the impacts. The results of experiments conducted on a twelve-cylinder ICE test rig show that the approach is capable of extracting the commencement of valve closing impact accurately and using only one feature can give a superior monitoring of valve clearance. With the help of this technique, the valve clearance fault becomes detectable even without the comparison to the baseline, and the changing trend of the clearance could be trackable.

  6. AF-DHNN: Fuzzy Clustering and Inference-Based Node Fault Diagnosis Method for Fire Detection.

    Science.gov (United States)

    Jin, Shan; Cui, Wen; Jin, Zhigang; Wang, Ying

    2015-07-17

    Wireless Sensor Networks (WSNs) have been utilized for node fault diagnosis in the fire detection field since the 1990s. However, the traditional methods have some problems, including complicated system structures, intensive computation needs, unsteady data detection and local minimum values. In this paper, a new diagnosis mechanism for WSN nodes is proposed, which is based on fuzzy theory and an Adaptive Fuzzy Discrete Hopfield Neural Network (AF-DHNN). First, the original status of each sensor over time is obtained with two features. One is the root mean square of the filtered signal (FRMS), the other is the normalized summation of the positive amplitudes of the difference spectrum between the measured signal and the healthy one (NSDS). Secondly, distributed fuzzy inference is introduced. The evident abnormal nodes' status is pre-alarmed to save time. Thirdly, according to the dimensions of the diagnostic data, an adaptive diagnostic status system is established with a Fuzzy C-Means Algorithm (FCMA) and Sorting and Classification Algorithm to reducing the complexity of the fault determination. Fourthly, a Discrete Hopfield Neural Network (DHNN) with iterations is improved with the optimization of the sensors' detected status information and standard diagnostic levels, with which the associative memory is achieved, and the search efficiency is improved. The experimental results show that the AF-DHNN method can diagnose abnormal WSN node faults promptly and effectively, which improves the WSN reliability.

  7. A Frequency-Weighted Energy Operator and complementary ensemble empirical mode decomposition for bearing fault detection

    Science.gov (United States)

    Imaouchen, Yacine; Kedadouche, Mourad; Alkama, Rezak; Thomas, Marc

    2017-01-01

    Signal processing techniques for non-stationary and noisy signals have recently attracted considerable attentions. Among them, the empirical mode decomposition (EMD) which is an adaptive and efficient method for decomposing signals from high to low frequencies into intrinsic mode functions (IMFs). Ensemble EMD (EEMD) is proposed to overcome the mode mixing problem of the EMD. In the present paper, the Complementary EEMD (CEEMD) is used for bearing fault detection. As a noise-improved method, the CEEMD not only overcomes the mode mixing, but also eliminates the residual of added white noise persisting into the IMFs and enhance the calculation efficiency of the EEMD method. Afterward, a selection method is developed to choose relevant IMFs containing information about defects. Subsequently, a signal is reconstructed from the sum of relevant IMFs and a Frequency-Weighted Energy Operator is tailored to extract both the amplitude and frequency modulations from the selected IMFs. This operator outperforms the conventional energy operator and the enveloping methods, especially in the presence of strong noise and multiple vibration interferences. Furthermore, simulation and experimental results showed that the proposed method improves performances for detecting the bearing faults. The method has also high computational efficiency and is able to detect the fault at an early stage of degradation.

  8. A neural network approach to fault detection in spacecraft attitude determination and control systems

    Science.gov (United States)

    Schreiner, John N.

    This thesis proposes a method of performing fault detection and isolation in spacecraft attitude determination and control systems. The proposed method works by deploying a trained neural network to analyze a set of residuals that are defined such that they encompass the attitude control, guidance, and attitude determination subsystems. Eight neural networks were trained using either the resilient backpropagation, Levenberg-Marquardt, or Levenberg-Marquardt with Bayesian regularization training algorithms. The results of each of the neural networks were analyzed to determine the accuracy of the networks with respect to isolating the faulty component or faulty subsystem within the ADCS. The performance of the proposed neural network-based fault detection and isolation method was compared and contrasted with other ADCS FDI methods. The results obtained via simulation showed that the best neural networks employing this method successfully detected the presence of a fault 79% of the time. The faulty subsystem was successfully isolated 75% of the time and the faulty components within the faulty subsystem were isolated 37% of the time.

  9. AF-DHNN: Fuzzy Clustering and Inference-Based Node Fault Diagnosis Method for Fire Detection

    Directory of Open Access Journals (Sweden)

    Shan Jin

    2015-07-01

    Full Text Available Wireless Sensor Networks (WSNs have been utilized for node fault diagnosis in the fire detection field since the 1990s. However, the traditional methods have some problems, including complicated system structures, intensive computation needs, unsteady data detection and local minimum values. In this paper, a new diagnosis mechanism for WSN nodes is proposed, which is based on fuzzy theory and an Adaptive Fuzzy Discrete Hopfield Neural Network (AF-DHNN. First, the original status of each sensor over time is obtained with two features. One is the root mean square of the filtered signal (FRMS, the other is the normalized summation of the positive amplitudes of the difference spectrum between the measured signal and the healthy one (NSDS. Secondly, distributed fuzzy inference is introduced. The evident abnormal nodes’ status is pre-alarmed to save time. Thirdly, according to the dimensions of the diagnostic data, an adaptive diagnostic status system is established with a Fuzzy C-Means Algorithm (FCMA and Sorting and Classification Algorithm to reducing the complexity of the fault determination. Fourthly, a Discrete Hopfield Neural Network (DHNN with iterations is improved with the optimization of the sensors’ detected status information and standard diagnostic levels, with which the associative memory is achieved, and the search efficiency is improved. The experimental results show that the AF-DHNN method can diagnose abnormal WSN node faults promptly and effectively, which improves the WSN reliability.

  10. Fault Diagnosis of Internal Combustion Engine Valve Clearance Using the Impact Commencement Detection Method

    Directory of Open Access Journals (Sweden)

    Zhinong Jiang

    2017-12-01

    Full Text Available Internal combustion engines (ICEs are widely used in many important fields. The valve train clearance of an ICE usually exceeds the normal value due to wear or faulty adjustment. This work aims at diagnosing the valve clearance fault based on the vibration signals measured on the engine cylinder heads. The non-stationarity of the ICE operating condition makes it difficult to obtain the nominal baseline, which is always an awkward problem for fault diagnosis. This paper overcomes the problem by inspecting the timing of valve closing impacts, of which the referenced baseline can be obtained by referencing design parameters rather than extraction during healthy conditions. To accurately detect the timing of valve closing impact from vibration signals, we carry out a new method to detect and extract the commencement of the impacts. The results of experiments conducted on a twelve-cylinder ICE test rig show that the approach is capable of extracting the commencement of valve closing impact accurately and using only one feature can give a superior monitoring of valve clearance. With the help of this technique, the valve clearance fault becomes detectable even without the comparison to the baseline, and the changing trend of the clearance could be trackable.

  11. Data-driven fault detection, isolation and estimation of aircraft gas turbine engine actuator and sensors

    Science.gov (United States)

    Naderi, E.; Khorasani, K.

    2018-02-01

    In this work, a data-driven fault detection, isolation, and estimation (FDI&E) methodology is proposed and developed specifically for monitoring the aircraft gas turbine engine actuator and sensors. The proposed FDI&E filters are directly constructed by using only the available system I/O data at each operating point of the engine. The healthy gas turbine engine is stimulated by a sinusoidal input containing a limited number of frequencies. First, the associated system Markov parameters are estimated by using the FFT of the input and output signals to obtain the frequency response of the gas turbine engine. These data are then used for direct design and realization of the fault detection, isolation and estimation filters. Our proposed scheme therefore does not require any a priori knowledge of the system linear model or its number of poles and zeros at each operating point. We have investigated the effects of the size of the frequency response data on the performance of our proposed schemes. We have shown through comprehensive case studies simulations that desirable fault detection, isolation and estimation performance metrics defined in terms of the confusion matrix criterion can be achieved by having access to only the frequency response of the system at only a limited number of frequencies.

  12. Optimal Cost-Effective Maintenance Policy for a Helicopter Gearbox Early Fault Detection under Varying Load

    Directory of Open Access Journals (Sweden)

    Xin Li

    2017-01-01

    Full Text Available Most of the existing fault detection methods rarely consider the cost-optimal maintenance policy. A novel multivariate Bayesian control approach is proposed, which enables the implementation of early fault detection for a helicopter gearbox with cost minimization maintenance policy under varying load. A continuous time hidden semi-Markov model (HSMM is employed to describe the stochastic relationship between the unobservable states and observable observations of the gear system. Explicit expressions for the remaining useful life prediction are derived using HSMM. Considering the maintenance cost in fault detection, the multivariate Bayesian control scheme based on HSMM is developed; the objective is to minimize the long-run expected average cost per unit time. An effective computational algorithm in the semi-Markov decision process (SMDP framework is designed to obtain the optimal control limit. A comparison with the multivariate Bayesian control chart based on hidden Markov model (HMM and the traditional age-based replacement policy is given, which illustrates the effectiveness of the proposed approach.

  13. Customized multiwavelets for planetary gearbox fault detection based on vibration sensor signals.

    Science.gov (United States)

    Sun, Hailiang; Zi, Yanyang; He, Zhengjia; Yuan, Jing; Wang, Xiaodong; Chen, Lue

    2013-01-18

    Planetary gearboxes exhibit complicated dynamic responses which are more difficult to detect in vibration signals than fixed-axis gear trains because of the special gear transmission structures. Diverse advanced methods have been developed for this challenging task to reduce or avoid unscheduled breakdown and catastrophic accidents. It is feasible to make fault features distinct by using multiwavelet denoising which depends on the feature separation and the threshold denoising. However, standard and fixed multiwavelets are not suitable for accurate fault feature detections because they are usually independent of the measured signals. To overcome this drawback, a method to construct customized multiwavelets based on the redundant symmetric lifting scheme is proposed in this paper. A novel indicator which combines kurtosis and entropy is applied to select the optimal multiwavelets, because kurtosis is sensitive to sharp impulses and entropy is effective for periodic impulses. The improved neighboring coefficients method is introduced into multiwavelet denoising. The vibration signals of a planetary gearbox from a satellite communication antenna on a measurement ship are captured under various motor speeds. The results show the proposed method could accurately detect the incipient pitting faults on two neighboring teeth in the planetary gearbox.

  14. Multi-scale investigation into the mechanisms of fault mirror formation in seismically active carbonate rocks

    Science.gov (United States)

    Ohl, Markus; Chatzaras, Vasileios; Niemeijer, Andre; King, Helen; Drury, Martyn; Plümper, Oliver

    2017-04-01

    Mirror surfaces along principal slip zones in carbonate rocks have recently received considerable attention as they are thought to form during fault slip at seismic velocities and thus may be a marker for paleo-seismicity (Siman-Tov et al., 2013). Therefore, these structures represent an opportunity to improve our understanding of earthquake mechanics in carbonate faults. Recent investigations reported the formation of fault mirrors in natural rocks as well as in laboratory experiments and connected their occurrence to the development of nano-sized granular material (Spagnuolo et al., 2015). However, the underlying formation and deformation mechanisms of these fault mirrors are still poorly constrained and warrant further research. In order to understand the influence and significance of these fault products on the overall fault behavior, we analysed the micro-, and nanostructural inventory of natural fault samples containing mirror slip surfaces. Here we present first results on the possible formation mechanisms of fault mirrors and associated deformation mechanisms operating in the carbonate fault gouge from two seismically active fault zones in central Greece. Our study specifically focuses on mirror slip surfaces obtained from the Arkitsa fault in the Gulf of Evia and the Schinos fault in the Gulf of Corinth. The Schinos fault was reactivated by a magnitude 6.7 earthquake in 1981 while the Arkitsa fault is thought to have been reactivated by a magnitude 6.9 earthquake in 1894. Our investigations encompass a combination of state-of-the-art analytical techniques including X-ray computed tomography, focused ion beam scanning electron microscopy (FIB-SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using this multiscale analytical approach, we report decarbonation-reaction structures, considerable calcite twinning and grain welding immediately below the mirror slip surface. Grains or areas indicating decarbonation reactions show a foam

  15. Fault Detection and Location by Static Switches in Microgrids Using Wavelet Transform and Adaptive Network-Based Fuzzy Inference System

    Directory of Open Access Journals (Sweden)

    Ying-Yi Hong

    2014-04-01

    Full Text Available Microgrids are a highly efficient means of embedding distributed generation sources in a power system. However, if a fault occurs inside or outside the microgrid, the microgrid should be immediately disconnected from the main grid using a static switch installed at the secondary side of the main transformer near the point of common coupling (PCC. The static switch should have a reliable module implemented in a chip to detect/locate the fault and activate the breaker to open the circuit immediately. This paper proposes a novel approach to design this module in a static switch using the discrete wavelet transform (DWT and adaptive network-based fuzzy inference system (ANFIS. The wavelet coefficient of the fault voltage and the inference results of ANFIS with the wavelet energy of the fault current at the secondary side of the main transformer determine the control action (open or close of a static switch. The ANFIS identifies the faulty zones inside or outside the microgrid. The proposed method is applied to the first outdoor microgrid test bed in Taiwan, with a generation capacity of 360.5 kW. This microgrid test bed is studied using the real-time simulator eMegaSim developed by Opal-RT Technology Inc. (Montreal, QC, Canada. The proposed method based on DWT and ANFIS is implemented in a field programmable gate array (FPGA by using the Xilinx System Generator. Simulation results reveal that the proposed method is efficient and applicable in the real-time control environment of a power system.

  16. Real Time Supervisors and Monitors for Performing Health Monitoring and Fault Detection for Systems Operating in Multiple Regimes

    National Research Council Canada - National Science Library

    Jaw, Link

    2003-01-01

    In this Phase I STTR, SMI and ARL have developed a Real Time Supervisor for fault detection and system reconfiguration in a team of micro UAVs, that are tasked to perform a team mission like surveillance or rendezvous...

  17. Investigation of late Pleistocene and Holocene activity in the San Gregorio fault zone on the continental slope north of Monterey Canyon, offshore central California

    Science.gov (United States)

    Maier, Katherine L.; Paull, Charles K.; Brothers, Daniel; Caress, David W.; McGann, Mary; Lundsten, Eve M.; Anderson, Krystle; Gwiazda, Roberto

    2017-01-01

    We provide an extensive high‐resolution geophysical, sediment core, and radiocarbon dataset to address late Pleistocene and Holocene fault activity of the San Gregorio fault zone (SGFZ), offshore central California. The SGFZ occurs primarily offshore in the San Andreas fault system and has been accommodating dextral strike‐slip motion between the Pacific and North American plates since the mid‐Miocene. Our study focuses on the SGFZ where it has been mapped through the continental slope north of Monterey Canyon. From 2009 to 2015, the Monterey Bay Aquarium Research Institute collected high‐resolution multibeam bathymetry and chirp sub‐bottom profiles using an autonomous underwater vehicle (AUV). Targeted samples were collected using a remotely operated vehicle (ROV) to provide radiocarbon age constraints. We integrate the high‐resolution geophysical data with radiocarbon dates to reveal Pleistocene seismic horizons vertically offset less than 5 m on nearly vertical faults. These faults are buried by continuous reflections deposited after ∼17.5  ka and likely following erosion during the last sea‐level lowstand ∼21  ka, bracketing the age of faulting to ∼32–21  ka. Clearly faulted horizons are only detected in a small area where mass wasting exhumed older strata to within ∼25  m of the seafloor. The lack of clearly faulted Holocene deposits and possible highly distributed faulting in the study area are consistent with previous interpretations that late Pleistocene and Holocene activity along the SGFZ may decrease to the south. This study illustrates the complexity of the SGFZ, offshore central California, and demonstrates the utility of very high‐resolution data from combined AUV (geophysical)–ROV (seabed sampling) surveys in offshore studies of fault activity.

  18. Touhuanping Fault, an active wrench fault within fold-and-thrust belt in northwestern Taiwan, documented by spatial analysis of fluvial terraces

    Science.gov (United States)

    Ota, Yoko; Lin, Yu-Nung Nina; Chen, Yue-Gau; Matsuta, Nobuhisa; Watanuki, Takuya; Chen, Ya-Wen

    2009-09-01

    This study aims at the recent activity and development of an active wrench fault, the Touhuanping Fault in northwestern Taiwan. Northwestern Taiwan has been proposed in a current situation between the mature to waning collision in terms of tectonic evolution. The main drainage in this area, the Chungkang River, flows close to the trace of the fault mentioned above. We examined various types of deformation of fluvial terraces along the Chungkang River as a key to understanding the nature and rate of the late Quaternary tectonics. The E-W trending Touhuanping Fault has long been mapped as a geological boundary fault, but its recent activity was suspected. Field survey revealed that its late Quaternary activity is recorded in the offset fluvial terraces. Our result shows dextral slip and vertical offset with upthrown side on the south, and activated at least twice since the emergence of terrace 4 (older terrace 3 with OSL date of ca. 80 ka). Total amount of offset recorded in the Touhuanping terrace sequence is 15 m for dextral and 10 m for vertical offset. Estimated recurrence time of earthquake rupture may be a few tens of thousand years. Uplift on the upthrown side of the Touhuanping Fault also resulted in the formation of drowned valleys which were graded to terrace 4. Other deformation features, such as back-tilting, westward warping, and a range-facing straight scarp, were also identified. A second-order anticline roughly parallel to the Touhuanping Fault is suggested to be the origin of the northward tilting on terrace 3; it could have resulted from a flower structure on the Touhuanping Fault at shallow depth. This may demonstrate that the buried segment of the Touhuanping Fault has also been active since 80 ka. In the northern study area, the westward warping at terrace 2 probably represents late Quaternary activity of another NE-SW trending Hsincheng Fault.

  19. Model-based fault detection for generator cooling system in wind turbines using SCADA data

    DEFF Research Database (Denmark)

    Borchersen, Anders Bech; Kinnaert, Michel

    2016-01-01

    was issued. This is an improvement compared with the current system that gives 15 detections and more than 10 false alarms. In some cases, the method detects the fault a long time before the turbine reports an alarm. A further advantage of the method is that it is based on supervisory control and data...... acquisition data that are available for the operator of all modern turbines. Thereby, the method can be implemented without the need to modify or install additional components in the turbines. Copyright © 2015 John Wiley & Sons, Ltd....

  20. Model-Based Fault Detection and Isolation of a Liquid-Cooled Frequency Converter on a Wind Turbine

    DEFF Research Database (Denmark)

    Li, Peng; Odgaard, Peter Fogh; Stoustrup, Jakob

    2012-01-01

    With the rapid development of wind energy technologies and growth of installed wind turbine capacity in the world, the reliability of the wind turbine becomes an important issue for wind turbine manufactures, owners, and operators. The reliability of the wind turbine can be improved by implementing...... on the developed dynamical model. The designed fault detection and isolation algorithm is applied on a set of measured experiment data in which different faults are artificially introduced to the scaled cooling system. The experimental results conclude that the different faults are successfully detected...

  1. Application of the Continuous-Discrete Extended Kalman Filter for Fault Detection in Continuous Glucose Monitors for Type 1 Diabetes

    DEFF Research Database (Denmark)

    Mahmoudi, Zeinab; Boiroux, Dimitri; Hagdrup, Morten

    2016-01-01

    The purpose of this study is the online detection of faults and anomalies of a continuous glucose monitor (CGM). We simulated a type 1 diabetes patient using the Medtronic virtual patient model. The model is a system of stochastic differential equations and includes insulin pharmacokinetics......, insulin-glucose interaction, and carbohydrate absorption. We simulated and detected two types of CGM faults, i.e., spike and drift. A fault was defined as a CGM value in any of the zones C, D, and E of the Clarke error grid analysis classification. Spike was modelled by a binomial distribution, and drift...

  2. Application of the continuous-discrete extended Kalman filter for fault detection in continuous glucose monitors for type 1 diabetes

    DEFF Research Database (Denmark)

    Mahmoudi, Zeinab; Boiroux, Dimitri; Hagdrup, Morten

    2017-01-01

    The purpose of this study is the online detection of faults and anomalies of a continuous glucose monitor (CGM). We simulated a type 1 diabetes patient using the Medtronic virtual patient model. The model is a system of stochastic differential equations and includes insulin pharmacokinetics......, insulin-glucose interaction, and carbohydrate absorption. We simulated and detected two types of CGM faults, i.e., spike and drift. A fault was defined as a CGM value in any of the zones C, D, and E of the Clarke error grid analysis classification. Spike was modelled by a binomial distribution, and drift...

  3. Fault detection and isolation of PEM fuel cell system based on nonlinear analytical redundancy. An application via parity space approach

    Science.gov (United States)

    Aitouche, A.; Yang, Q.; Ould Bouamama, B.

    2011-05-01

    This paper presents a procedure dealing with the issue of fault detection and isolation (FDI) using nonlinear analytical redundancy (NLAR) technique applied in a proton exchange membrane (PEM) fuel cell system based on its mathematic model. The model is proposed and simplified into a five orders state space representation. The transient phenomena captured in the model include the compressor dynamics, the flow characteristics, mass and energy conservation and manifold fluidic mechanics. Nonlinear analytical residuals are generated based on the elimination of the unknown variables of the system by an extended parity space approach to detect and isolate actuator and sensor faults. Finally, numerical simulation results are given corresponding to a faults signature matrix.

  4. An Aspect-Oriented Programming-based approach to software development for fault detection in measurement systems

    CERN Document Server

    Arpaia, P; Inglese, Vitaliano; Bernardi, Mario Luca; Di Lucca, Giuseppe; Spiezia, Giovanni

    2010-01-01

    An Aspect-Oriented Programming-based approach to the development of software components for fault detection in automatic measurement systems is proposed. Faults are handled by means of specific software units, the ``aspects{''}, in order to better modularize issues transversal to several components. As a case study, this approach was applied to the design of the fault detection software inside a flexible framework for magnetic measurements, developed at the European Organization for Nuclear Research (CERN). Experimental results of software modularity and performance measurements for comparing aspect- and objectoriented solutions in rotating coils tests on superconducting magnets are reported. (C) 2009 Elsevier B.V. All rights reserved.

  5. PEM fuel cell fault detection and identification using differential method: simulation and experimental validation

    Science.gov (United States)

    Frappé, E.; de Bernardinis, A.; Bethoux, O.; Candusso, D.; Harel, F.; Marchand, C.; Coquery, G.

    2011-05-01

    PEM fuel cell performance and lifetime strongly depend on the polymer membrane and MEA hydration. As the internal moisture is very sensitive to the operating conditions (temperature, stoichiometry, load current, water management…), keeping the optimal working point is complex and requires real-time monitoring. This article focuses on PEM fuel cell stack health diagnosis and more precisely on stack fault detection monitoring. This paper intends to define new, simple and effective methods to get relevant information on usual faults or malfunctions occurring in the fuel cell stack. For this purpose, the authors present a fault detection method using simple and non-intrusive on-line technique based on the space signature of the cell voltages. The authors have the objective to minimize the number of embedded sensors and instrumentation in order to get a precise, reliable and economic solution in a mass market application. A very low number of sensors are indeed needed for this monitoring and the associated algorithm can be implemented on-line. This technique is validated on a 20-cell PEMFC stack. It demonstrates that the developed method is particularly efficient in flooding case. As a matter of fact, it uses directly the stack as a sensor which enables to get a quick feedback on its state of health.

  6. Bond Graph Modelling for Fault Detection and Isolation of an Ultrasonic Linear Motor

    Directory of Open Access Journals (Sweden)

    Mabrouk KHEMLICHE

    2010-12-01

    Full Text Available In this paper Bond Graph modeling, simulation and monitoring of ultrasonic linear motors are presented. Only the vibration of piezoelectric ceramics and stator will be taken into account. Contact problems between stator and rotor are not treated here. So, standing and travelling waves will be briefly presented since the majority of the motors use another wave type to generate the stator vibration and thus obtain the elliptic trajectory of the points on the surface of the stator in the first time. Then, electric equivalent circuit will be presented with the aim for giving a general idea of another way of graphical modelling of the vibrator introduced and developed. The simulations of an ultrasonic linear motor are then performed and experimental results on a prototype built at the laboratory are presented. Finally, validation of the Bond Graph method for modelling is carried out, comparing both simulation and experiment results. This paper describes the application of the FDI approach to an electrical system. We demonstrate the FDI effectiveness with real data collected from our automotive test. We introduce the analysis of the problem involved in the faults localization in this process. We propose a method of fault detection applied to the diagnosis and to determine the gravity of a detected fault. We show the possibilities of application of the new approaches to the complex system control.

  7. A SVM framework for fault detection of the braking system in a high speed train

    Science.gov (United States)

    Liu, Jie; Li, Yan-Fu; Zio, Enrico

    2017-03-01

    In April 2015, the number of operating High Speed Trains (HSTs) in the world has reached 3603. An efficient, effective and very reliable braking system is evidently very critical for trains running at a speed around 300 km/h. Failure of a highly reliable braking system is a rare event and, consequently, informative recorded data on fault conditions are scarce. This renders the fault detection problem a classification problem with highly unbalanced data. In this paper, a Support Vector Machine (SVM) framework, including feature selection, feature vector selection, model construction and decision boundary optimization, is proposed for tackling this problem. Feature vector selection can largely reduce the data size and, thus, the computational burden. The constructed model is a modified version of the least square SVM, in which a higher cost is assigned to the error of classification of faulty conditions than the error of classification of normal conditions. The proposed framework is successfully validated on a number of public unbalanced datasets. Then, it is applied for the fault detection of braking systems in HST: in comparison with several SVM approaches for unbalanced datasets, the proposed framework gives better results.

  8. Bearing fault detection using motor current signal analysis based on wavelet packet decomposition and Hilbert envelope

    Directory of Open Access Journals (Sweden)

    Imaouchen Yacine

    2015-01-01

    Full Text Available To detect rolling element bearing defects, many researches have been focused on Motor Current Signal Analysis (MCSA using spectral analysis and wavelet transform. This paper presents a new approach for rolling element bearings diagnosis without slip estimation, based on the wavelet packet decomposition (WPD and the Hilbert transform. Specifically, the Hilbert transform first extracts the envelope of the motor current signal, which contains bearings fault-related frequency information. Subsequently, the envelope signal is adaptively decomposed into a number of frequency bands by the WPD algorithm. Two criteria based on the energy and correlation analyses have been investigated to automate the frequency band selection. Experimental studies have confirmed that the proposed approach is effective in diagnosing rolling element bearing faults for improved induction motor condition monitoring and damage assessment.

  9. Simultaneous Fault Detection and Sensor Selection for Condition Monitoring of Wind Turbines

    Directory of Open Access Journals (Sweden)

    Wenna Zhang

    2016-04-01

    Full Text Available Data collected from the supervisory control and data acquisition (SCADA system are used widely in wind farms to obtain operation and performance information about wind turbines. The paper presents a three-way model by means of parallel factor analysis (PARAFAC for wind turbine fault detection and sensor selection, and evaluates the method with SCADA data obtained from an operational farm. The main characteristic of this new approach is that it can be used to simultaneously explore measurement sample profiles and sensors profiles to avoid discarding potentially relevant information for feature extraction. With K-means clustering method, the measurement data indicating normal, fault and alarm conditions of the wind turbines can be identified, and the sensor array can be optimised for effective condition monitoring.

  10. Direct detection of near-surface faults by migration of back-scattered surface waves

    KAUST Repository

    Yu, Han

    2014-08-05

    We show that diffraction stack migration can be used to estimate the distribution of near-surface faults. The assumption is that near-surface faults generate detectable back-scattered surface waves from impinging surface waves. The processing steps are to isolate the back-scattered surface waves, and then migrate them by diffraction migration using the surface wave velocity as the migration velocity. Instead of summing events along trial quasi-hyperbolas, surface wave migration sums events along trial quasi-linear trajectories that correspond to the moveout of back-scattered surface waves. A deconvolution filter derived from the data can be used to collapse a dispersive arrival into a non-dispersive event. Results with synthetic data and field records validate the feasibility of this method. Applying this method to USArray data or passively recorded exploration data might open new opportunities in mapping tectonic features over the extent of the array.

  11. Real World Experience With Ion Implant Fault Detection at Freescale Semiconductor

    Science.gov (United States)

    Sing, David C.; Breeden, Terry; Fakhreddine, Hassan; Gladwin, Steven; Locke, Jason; McHugh, Jim; Rendon, Michael

    2006-11-01

    The Freescale automatic fault detection and classification (FDC) system has logged data from over 3.5 million implants in the past two years. The Freescale FDC system is a low cost system which collects summary implant statistics at the conclusion of each implant run. The data is collected by either downloading implant data log files from the implant tool workstation, or by exporting summary implant statistics through the tool's automation interface. Compared to the traditional FDC systems which gather trace data from sensors on the tool as the implant proceeds, the Freescale FDC system cannot prevent scrap when a fault initially occurs, since the data is collected after the implant concludes. However, the system can prevent catastrophic scrap events due to faults which are not detected for days or weeks, leading to the loss of hundreds or thousands of wafers. At the Freescale ATMC facility, the practical applications of the FD system fall into two categories: PM trigger rules which monitor tool signals such as ion gauges and charge control signals, and scrap prevention rules which are designed to detect specific failure modes that have been correlated to yield loss and scrap. PM trigger rules are designed to detect shifts in tool signals which indicate normal aging of tool systems. For example, charging parameters gradually shift as flood gun assemblies age, and when charge control rules start to fail a flood gun PM is performed. Scrap prevention rules are deployed to detect events such as particle bursts and excessive beam noise, events which have been correlated to yield loss. The FDC system does have tool log-down capability, and scrap prevention rules often use this capability to automatically log the tool into a maintenance state while simultaneously paging the sustaining technician for data review and disposition of the affected product.

  12. Gear Fault Detection Effectiveness as Applied to Tooth Surface Pitting Fatigue Damage

    Science.gov (United States)

    Lewicki, David G.; Dempsey, Paula J.; Heath, Gregory F.; Shanthakumaran, Perumal

    2010-01-01

    A study was performed to evaluate fault detection effectiveness as applied to gear-tooth-pitting-fatigue damage. Vibration and oil-debris monitoring (ODM) data were gathered from 24 sets of spur pinion and face gears run during a previous endurance evaluation study. Three common condition indicators (RMS, FM4, and NA4 [Ed. 's note: See Appendix A-Definitions D were deduced from the time-averaged vibration data and used with the ODM to evaluate their performance for gear fault detection. The NA4 parameter showed to be a very good condition indicator for the detection of gear tooth surface pitting failures. The FM4 and RMS parameters perfomu:d average to below average in detection of gear tooth surface pitting failures. The ODM sensor was successful in detecting a significant 8lDOunt of debris from all the gear tooth pitting fatigue failures. Excluding outliers, the average cumulative mass at the end of a test was 40 mg.

  13. Postglacial seismic activity along the Isovaara-Riikonkumpu fault complex

    Science.gov (United States)

    Ojala, Antti E. K.; Mattila, Jussi; Ruskeeniemi, Timo; Palmu, Jukka-Pekka; Lindberg, Antero; Hänninen, Pekka; Sutinen, Raimo

    2017-10-01

    Analysis of airborne LiDAR-based digital elevation models (DEMs), trenching of Quaternary deposits, and diamond drilling through faulted bedrock was conducted to characterize the geological structure and full slip profiles of the Isovaara-Riikonkumpu postglacial fault (PGF) complex in northern Finland. The PGF systems are recognized from LiDAR DEMs as a complex of surface ruptures striking SW-NE, cutting through late-Weichselian till, and associated with several postglacial landslides within 10 km. Evidence from the terrain rupture characteristics, the deformed and folded structure of late-Weichselian till, and the 14C age of 11,300 cal BP from buried organic matter underneath the Sotka landslide indicates a postglacial origin of the Riikonkumpu fault (PGF). The fracture frequency and lithology of drill cores and fault geometry in the trench log indicate that the Riikonkumpu PGF dips to WNW with a dip angle of 40-45° at the Riikonkumpu site and close to 60° at the Riikonvaara site. A fault length of 19 km and the mean and maximum cumulative vertical displacement of 1.3 m and 4.1 m, respectively, of the Riikonkumpu PGF system indicate that the fault potentially hosted an earthquake with a moment magnitude MW ≈ 6.7-7.3 assuming that slip was accumulated in one seismic event. Our interpretation further suggests that the Riikonkumpu PGF system is linked to the Isovaara PGF system and that, together, they form a larger Isovaara-Riikonkumpu fault complex. Relationships between the 38-km-long rupture of the Isovaara-Riikonkumpu complex and the fault offset parameters, with cumulative displacement of 1.5 and 8.3 m, respectively, indicate that the earthquake(s) contributing to the PGF complex potentially had a moment magnitude of MW ≈ 6.9-7.5. In order to adequately sample the uncertainty space, the moment magnitude was also estimated for each major segment within the Isovaara-Riikonkumpu PGF complex. These estimates vary roughly between MW ≈ 5-8 for the individual

  14. Fault detection, isolation, and diagnosis of status self-validating gas sensor arrays.

    Science.gov (United States)

    Chen, Yin-Sheng; Xu, Yong-Hui; Yang, Jing-Li; Shi, Zhen; Jiang, Shou-da; Wang, Qi

    2016-04-01

    The traditional gas sensor array has been viewed as a simple apparatus for information acquisition in chemosensory systems. Gas sensor arrays frequently undergo impairments in the form of sensor failures that cause significant deterioration of the performance of previously trained pattern recognition models. Reliability monitoring of gas sensor arrays is a challenging and critical issue in the chemosensory system. Because of its importance, we design and implement a status self-validating gas sensor array prototype to enhance the reliability of its measurements. A novel fault detection, isolation, and diagnosis (FDID) strategy is presented in this paper. The principal component analysis-based multivariate statistical process monitoring model can effectively perform fault detection by using the squared prediction error statistic and can locate the faulty sensor in the gas sensor array by using the variables contribution plot. The signal features of gas sensor arrays for different fault modes are extracted by using ensemble empirical mode decomposition (EEMD) coupled with sample entropy (SampEn). The EEMD is applied to adaptively decompose the original gas sensor signals into a finite number of intrinsic mode functions (IMFs) and a residual. The SampEn values of each IMF and the residual are calculated to reveal the multi-scale intrinsic characteristics of the faulty sensor signals. Sparse representation-based classification is introduced to identify the sensor fault type for the purpose of diagnosing deterioration in the gas sensor array. The performance of the proposed strategy is compared with other different diagnostic approaches, and it is fully evaluated in a real status self-validating gas sensor array experimental system. The experimental results demonstrate that the proposed strategy provides an excellent solution to the FDID of status self-validating gas sensor arrays.

  15. Evaluation of the slip-tendency of active faults in the Japanese islands

    Science.gov (United States)

    Yukutake, Y.; Takeda, T.; Yoshida, A.

    2013-12-01

    In evaluating the potential for fault activity, it is important to consider the stress state acting on the fault plane of interest. To this end, Morris et al. (1996) proposed a parameter termed 'slip-tendency', defined as the ratio of shear stress to normal stress acting on the fault plane. A high slip-tendency means that fault activity is likely in the current stress field. In this study, we estimated the stress field around active faults in the Japanese Islands based on earthquake focal mechanisms, and evaluated the slip-tendencies of the faults. We determined the focal mechanisms of earthquakes that occurred in the Japanese Islands between 2004 and 2010, using P-wave polarities and P/SH wave amplitudes. Focal mechanisms for 8000 events were obtained. Applying the stress inversion method (Hardebeck and Michael, 2006) to the focal mechanisms data, we estimated the stress state around known active faults. In applying the method, we set grid points at intervals of 0.1° in both longitude and latitude. We estimated the stress field only for grid point where at least eight focal mechanism solutions were available in the sub-region within ×0.05° of the grid point. Information on the location, strike, and dip angle of active faults was obtained from the Active Fault Database of Japan administered by the National Institute of Advanced Industrial Science and Technology (http://riodb02.ibase.aist.go.jp/activefault/). The stress inversion method yields information on the orientations of the three principal stress axes and the stress ratio (σ2-σ3/σ1-σ3). To calculate the slip-tendency, it is necessary to calculate the pore pressure, the absolute stress value, and the magnitude of differential stress. The pore pressure was assumed to be hydrostatic pressure. The overburden stress (σv = ρgz) was regarded as the absolute value of one of the principal stresses, when a principal stress axis was almost vertical. The magnitude of differential stress was estimated from the

  16. Fault detection and diagnosis of a gearbox in marine propulsion systems using bispectrum analysis and artificial neural networks

    Science.gov (United States)

    Li, Zhixiong; Yan, Xinping; Yuan, Chengqing; Zhao, Jiangbin; Peng, Zhongxiao

    2011-03-01

    A marine propulsion system is a very complicated system composed of many mechanical components. As a result, the vibration signal of a gearbox in the system is strongly coupled with the vibration signatures of other components including a diesel engine and main shaft. It is therefore imperative to assess the coupling effect on diagnostic reliability in the process of gear fault diagnosis. For this reason, a fault detection and diagnosis method based on bispectrum analysis and artificial neural networks (ANNs) was proposed for the gearbox with consideration given to the impact of the other components in marine propulsion systems. To monitor the gear conditions, the bispectrum analysis was first employed to detect gear faults. The amplitude-frequency plots containing gear characteristic signals were then attained based on the bispectrum technique, which could be regarded as an index actualizing forepart gear faults diagnosis. Both the back propagation neural network (BPNN) and the radial-basis function neural network (RBFNN) were applied to identify the states of the gearbox. The numeric and experimental test results show the bispectral patterns of varying gear fault severities are different so that distinct fault features of the vibrant signal of a marine gearbox can be extracted effectively using the bispectrum, and the ANN classification method has achieved high detection accuracy. Hence, the proposed diagnostic techniques have the capability of diagnosing marine gear faults in the earlier phases, and thus have application importance.

  17. Weighted low-rank sparse model via nuclear norm minimization for bearing fault detection

    Science.gov (United States)

    Du, Zhaohui; Chen, Xuefeng; Zhang, Han; Yang, Boyuan; Zhai, Zhi; Yan, Ruqiang

    2017-07-01

    It is a fundamental task in the machine fault diagnosis community to detect impulsive signatures generated by the localized faults of bearings. The main goal of this paper is to exploit the low-rank physical structure of periodic impulsive features and further establish a weighted low-rank sparse model for bearing fault detection. The proposed model mainly consists of three basic components: an adaptive partition window, a nuclear norm regularization and a weighted sequence. Firstly, due to the periodic repetition mechanism of impulsive feature, an adaptive partition window could be designed to transform the impulsive feature into a data matrix. The highlight of partition window is to accumulate all local feature information and align them. Then, all columns of the data matrix share similar waveforms and a core physical phenomenon arises, i.e., these singular values of the data matrix demonstrates a sparse distribution pattern. Therefore, a nuclear norm regularization is enforced to capture that sparse prior. However, the nuclear norm regularization treats all singular values equally and thus ignores one basic fact that larger singular values have more information volume of impulsive features and should be preserved as much as possible. Therefore, a weighted sequence with adaptively tuning weights inversely proportional to singular amplitude is adopted to guarantee the distribution consistence of large singular values. On the other hand, the proposed model is difficult to solve due to its non-convexity and thus a new algorithm is developed to search one satisfying stationary solution through alternatively implementing one proximal operator operation and least-square fitting. Moreover, the sensitivity analysis and selection principles of algorithmic parameters are comprehensively investigated through a set of numerical experiments, which shows that the proposed method is robust and only has a few adjustable parameters. Lastly, the proposed model is applied to the

  18. Extreme hydrothermal conditions at an active plate-bounding fault

    NARCIS (Netherlands)

    Sutherland, Rupert; Townend, John; Toy, Virginia; Upton, Phaedra; Coussens, Jamie; Allen, Michael; Baratin, Laura May; Barth, Nicolas; Becroft, Leeza; Boese, Carolin; Boles, Austin; Boulton, Carolyn; Broderick, Neil G.R.; Janku-Capova, Lucie; Carpenter, Brett M.; Célérier, Bernard; Chamberlain, Calum; Cooper, Alan; Coutts, Ashley; Cox, Simon; Craw, Lisa; Doan, Mai Linh; Eccles, Jennifer; Faulkner, Dan; Grieve, Jason; Grochowski, Julia; Gulley, Anton; Hartog, Arthur; Howarth, Jamie; Jacobs, Katrina; Jeppson, Tamara; Kato, Naoki; Keys, Steven; Kirilova, Martina; Kometani, Yusuke; Langridge, Rob; Lin, Weiren; Little, Timothy; Lukacs, Adrienn; Mallyon, Deirdre; Mariani, Elisabetta; Massiot, Cécile; Mathewson, Loren; Melosh, Ben; Menzies, Catriona; Moore, Jo; Morales, Luiz; Morgan, Chance; Mori, Hiroshi; Niemeijer, Andre|info:eu-repo/dai/nl/370832132; Nishikawa, Osamu; Prior, David; Sauer, Katrina; Savage, Martha; Schleicher, Anja; Schmitt, Douglas R.; Shigematsu, Norio; Taylor-Offord, Sam; Teagle, Damon; Tobin, Harold; Valdez, Robert; Weaver, Konrad; Wiersberg, Thomas; Williams, Jack; Woodman, Nick; Zimmer, Martin

    2017-01-01

    Temperature and fluid pressure conditions control rock deformation and mineralization on geological faults, and hence the distribution of earthquakes. Typical intraplate continental crust has hydrostatic fluid pressure and a near-surface thermal gradient of 31 ± 15 degrees Celsius per kilometre. At

  19. Evaluating the movement of active faults on buried pipelines | Parish ...

    African Journals Online (AJOL)

    During the earthquake, a buried pipeline may be experienced extreme loading that is the result of the relatively large displacement of the Earth along the pipe. Large movements of ground could occur by faulting, liquefaction, lateral spreading, landslides, and slope failures. Since the pipelines are widely spread, and in ...

  20. Examination of faults active motion on buried pipelines | Parish ...

    African Journals Online (AJOL)

    During an earthquake, a buried pipeline may experience a severe loading as the result of the ground relatively large displacement along the pipe. Large ground movements may occur by faulting, liquefaction, lateral spreading, landslides and slope failures. Since the pipelines are widely spread, and in some areas ...

  1. Detecting Blind Fault with Fractal and Roughness Factors from High Resolution LiDAR DEM at Taiwan

    Science.gov (United States)

    Cheng, Y. S.; Yu, T. T.

    2014-12-01

    There is no obvious fault scarp associated with blind fault. The traditional method of mapping this unrevealed geological structure is the cluster of seismicity. Neither the seismic event nor the completeness of cluster could be captured by network to chart the location of the entire possible active blind fault within short period of time. High resolution DEM gathered by LiDAR could denote actual terrain information despite the existence of plantation. 1-meter interval DEM of mountain region at Taiwan is utilized by fractal, entropy and roughness calculating with MATLAB code. By jointing these handing, the regions of non-sediment deposit are charted automatically. Possible blind fault associated with Chia-Sen earthquake at southern Taiwan is served as testing ground. GIS layer help in removing the difference from various geological formation, then multi-resolution fractal index is computed around the target region. The type of fault movement controls distribution of fractal index number. The scale of blind fault governs degree of change in fractal index. Landslide induced by rainfall and/or earthquake possesses larger degree of geomorphology alteration than blind fault; special treatment in removing these phenomena is required. Highly weathered condition at Taiwan should erase the possible trace remained upon DEM from the ruptured of blind fault while reoccurrence interval is higher than hundreds of years. This is one of the obstacle in finding possible blind fault at Taiwan.

  2. A Wireless Sensor System for Real-Time Monitoring and Fault Detection of Motor Arrays

    Directory of Open Access Journals (Sweden)

    Jonathan Medina-García

    2017-02-01

    Full Text Available This paper presents a wireless fault detection system for industrial motors that combines vibration, motor current and temperature analysis, thus improving the detection of mechanical faults. The design also considers the time of detection and further possible actions, which are also important for the early detection of possible malfunctions, and thus for avoiding irreversible damage to the motor. The remote motor condition monitoring is implemented through a wireless sensor network (WSN based on the IEEE 802.15.4 standard. The deployed network uses the beacon-enabled mode to synchronize several sensor nodes with the coordinator node, and the guaranteed time slot mechanism provides data monitoring with a predetermined latency. A graphic user interface offers remote access to motor conditions and real-time monitoring of several parameters. The developed wireless sensor node exhibits very low power consumption since it has been optimized both in terms of hardware and software. The result is a low cost, highly reliable and compact design, achieving a high degree of autonomy of more than two years with just one 3.3 V/2600 mAh battery. Laboratory and field tests confirm the feasibility of the wireless system.

  3. Tools for Evaluating Fault Detection and Diagnostic Methods for HVAC Secondary Systems

    Science.gov (United States)

    Pourarian, Shokouh

    Although modern buildings are using increasingly sophisticated energy management and control systems that have tremendous control and monitoring capabilities, building systems routinely fail to perform as designed. More advanced building control, operation, and automated fault detection and diagnosis (AFDD) technologies are needed to achieve the goal of net-zero energy commercial buildings. Much effort has been devoted to develop such technologies for primary heating ventilating and air conditioning (HVAC) systems, and some secondary systems. However, secondary systems, such as fan coil units and dual duct systems, although widely used in commercial, industrial, and multifamily residential buildings, have received very little attention. This research study aims at developing tools that could provide simulation capabilities to develop and evaluate advanced control, operation, and AFDD technologies for these less studied secondary systems. In this study, HVACSIM+ is selected as the simulation environment. Besides developing dynamic models for the above-mentioned secondary systems, two other issues related to the HVACSIM+ environment are also investigated. One issue is the nonlinear equation solver used in HVACSIM+ (Powell's Hybrid method in subroutine SNSQ). It has been found from several previous research projects (ASRHAE RP 825 and 1312) that SNSQ is especially unstable at the beginning of a simulation and sometimes unable to converge to a solution. Another issue is related to the zone model in the HVACSIM+ library of components. Dynamic simulation of secondary HVAC systems unavoidably requires an interacting zone model which is systematically and dynamically interacting with building surrounding. Therefore, the accuracy and reliability of the building zone model affects operational data generated by the developed dynamic tool to predict HVAC secondary systems function. The available model does not simulate the impact of direct solar radiation that enters a zone

  4. Bearing Fault Detection Using Multi-Scale Fractal Dimensions Based on Morphological Covers

    Directory of Open Access Journals (Sweden)

    Pei-Lin Zhang

    2012-01-01

    Full Text Available Vibration signals acquired from bearing have been found to demonstrate complicated nonlinear characteristics in literature. Fractal geometry theory has provided effective tools such as fractal dimension for characterizing the vibration signals in bearing faults detection. However, most of the natural signals are not critical self-similar fractals; the assumption of a constant fractal dimension at all scales may not be true. Motivated by this fact, this work explores the application of the multi-scale fractal dimensions (MFDs based on morphological cover (MC technique for bearing fault diagnosis. Vibration signals from bearing with seven different states under four operations conditions are collected to validate the presented MFDs based on MC technique. Experimental results reveal that the vibration signals acquired from bearing are not critical self-similar fractals. The MFDs can provide more discriminative information about the signals than the single global fractal dimension. Furthermore, three classifiers are employed to evaluate and compare the classification performance of the MFDs with other feature extraction methods. Experimental results demonstrate the MFDs to be a desirable approach to improve the performance of bearing fault diagnosis.

  5. Tacholess order-tracking approach for wind turbine gearbox fault detection

    Science.gov (United States)

    Wang, Yi; Xie, Yong; Xu, Guanghua; Zhang, Sicong; Hou, Chenggang

    2017-09-01

    Monitoring of wind turbines under variable-speed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

  6. A Method to Simultaneously Detect the Current Sensor Fault and Estimate the State of Energy for Batteries in Electric Vehicles.

    Science.gov (United States)

    Xu, Jun; Wang, Jing; Li, Shiying; Cao, Binggang

    2016-08-19

    Recently, State of energy (SOE) has become one of the most fundamental parameters for battery management systems in electric vehicles. However, current information is critical in SOE estimation and current sensor is usually utilized to obtain the latest current information. However, if the current sensor fails, the SOE estimation may be confronted with large error. Therefore, this paper attempts to make the following contributions: Current sensor fault detection and SOE estimation method is realized simultaneously. Through using the proportional integral observer (PIO) based method, the current sensor fault could be accurately estimated. By taking advantage of the accurate estimated current sensor fault, the influence caused by the current sensor fault can be eliminated and compensated. As a result, the results of the SOE estimation will be influenced little by the fault. In addition, the simulation and experimental workbench is established to verify the proposed method. The results indicate that the current sensor fault can be estimated accurately. Simultaneously, the SOE can also be estimated accurately and the estimation error is influenced little by the fault. The maximum SOE estimation error is less than 2%, even though the large current error caused by the current sensor fault still exists.

  7. Mechanical analysis of fault activation in southern Longmen Shan fold-and- thrust belt

    Science.gov (United States)

    Zhang, Zhen; Zhang, Huai; Wang, Liangshu; Shi, Yaolin; Leroy, Yves M.

    2017-04-01

    A mixed fault activation mode with obvious hinterland rupture in the southern Longmen Shan, the eastern margin of Tibetan Plateau, is revealed by recent 2008 Mw7.9 Wenchuan and 2013 Mw6.6 Lushan earthquakes together with GPS measurements. How to systematically understand the coexistence and competition mechanisms of fault activation, especially the principal-subordinate relationship on deformation absorption, in essence, involves mechanical onset analysis of this fold- and-thrust belt. However, due to the two-décollement- level thrust system with active 'flat-ramp- flat' geometry décollement, the predication of fault activation in the LMS has beyond the scope of Critical Coulomb wedge theory, not to mention the synchronous listric-type splay fault rupturing in the Beichuan fault (BCF) and Pengguan fault (PGF). For that purpose, we adopted maximum strength theorem, the kinematic approach of limit analysis, to deal with mechanical analysis of fault activation. Four end-member failure modes, or collapse mechanisms (CMs) in classical limit analysis, are proposed corresponding to the rupture of BCF, PGF, Range Frontal Blind Fault (RFBF) and the rupture of the flat-ramp- flat décollement into Sichuan Basin via RFBF. By selecting the available CMs via finite element limit analysis, the listric geometry of BCF and PGF is demonstrated to the dominant factor in trapping deformation in the hinterland. To activate the high-angle Beichuan splay fault, low cohesion and low friction angle on the BCF are combined effects on the rupturing of BCF. The change in cohesion and friction on BCF eventually forms the transition state between high angle BCF and low-angle PGF. Besides, due to the existence of low frictional upper décollement layer in Sichuan Basin (the Triassic evaporate layer), small amount of deformation is attracted into the Sichuan Basin forming small-scale thrusting folding. Moreover, favorable deformation migration toward Sichuan Basin is jointly influenced by

  8. Measurement of Instantaneous Angular Displacement Fluctuation and its applications on gearbox fault detection.

    Science.gov (United States)

    Li, Bing; Zhang, Xining; Wu, Tingting

    2018-02-08

    Recently, Instantaneous Angular Speed (IAS) measurement is successfully established and prevalently applied to a wide variety of machines due to the hypothesis that the speed fluctuation of rotating machinery carries plentiful dynamic responses. Nevertheless, exploration and application based on angular signal are still insufficient. Under the same hypothesis, in this paper, we introduced an extended algorithm named Instantaneous Angular Phase Demodulation (IAPD), together with the selection of optimal sideband family to extract the Instantaneous Angular Displacement Fluctuation (IADF) signal. In order to evaluate the performance of IADF signal, an effective approach was demonstrated using IADF signal to address the fault detection and diagnosis issue. After extracting the IADF signal, a much effective method was developed to deal with the large amount of data generated during the signal collection process. Then, we used the well-developed techniques, i.e., empirical mode decomposition (EMD) and envelope analysis, to undertake the signal de-noising and feature extraction task. The effectiveness and capability of the IADF signal were evaluated by two kinds of gearboxes under differentconditions in practice. In particular, the prevalent IAS signal and vibration signal were also involved and testified by the proposed procedure. Experimental results demonstrated that by means of the IADF signal, the combination of EMD and envelope analysis not only provided accurate identification results with a higher signal-to-noise ratio, but was also capable of revealing the fault characteristics significantly and effectively. In contrast, although the IAS signal had the potential ability to diagnose the serious fault, it failed for the slight crack case. Moreover, the same procedure even its improvements, i.e., ensemble empirical mode decomposition and local mean decomposition, all failed to recognize the faults in terms of vibration signals. Copyright © 2018 ISA. Published by

  9. Application of the Goertzel’s algorithm in the airgap mixed eccentricity fault detection

    Directory of Open Access Journals (Sweden)

    Reljić Dejan

    2015-01-01

    Full Text Available In this paper, a suitable method for the on-line detection of the airgap mixed eccentricity fault in a three-phase cage induction motor has been proposed. The method is based on a Motor Current Signature Analysis (MCSA approach, a technique that is often used for an induction motor condition monitoring and fault diagnosis. It is based on the spectral analysis of the stator line current signal and the frequency identification of specific components, which are created as a result of motor faults. The most commonly used method for the current signal spectral analysis is based on the Fast Fourier transform (FFT. However, due to the complexity and memory demands, the FFT algorithm is not always suitable for real-time systems. Instead of the whole spectrum analysis, this paper suggests only the spectral analysis on the expected airgap fault frequencies employing the Goertzel’s algorithm to predict the magnitude of these frequency components. The method is simple and can be implemented in real-time airgap mixed eccentricity monitoring systems without much computational effort. A low-cost data acquisition system, supported by the LabView software, has been used for the hardware and software implementation of the proposed method. The method has been validated by the laboratory experiments on both the line-connected and the inverter-fed three-phase fourpole cage induction motor operated at the rated frequency and under constant load at a few different values. In addition, the results of the proposed method have been verified through the motor’s vibration signal analysis. [Projekat Ministarstva nauke Republike Srbije, br. III42004

  10. Fault activity characteristics in the northern margin of the Tibetan Plateau before the Menyuan Ms6.4 earthquake

    Directory of Open Access Journals (Sweden)

    Dongzhuo Xu

    2016-07-01

    Full Text Available Fault deformation characteristics in the northern margin of the Tibetan Plateau before the Menyuan Ms6.4 earthquake are investigated through time-series and structural geological analysis based on cross-fault observation data from the Qilian Mountain–Haiyuan Fault belt and the West Qinling Fault belt. The results indicate: 1 Group short-term abnormal variations appeared in the Qilian Mountain–Haiyuan Fault belt and the West Qinling Fault belt before the Menyuan Ms6.4 earthquake. 2 More medium and short-term anomalies appear in the middle-eastern segment of the Qilian Mountain Fault belt and the West Qinling Fault belt, suggesting that the faults' activities are strong in these areas. The faults' activities in the middle-eastern segment of the Qilian Fault belt result from extensional stress, as before the earthquake, whereas those in the West Qinling Fault belt are mainly compressional. 3 In recent years, moderate-strong earthquakes occurred in both the Kunlun Mountain and the Qilian Mountain Fault belts, and some energy was released. It is possible that the seismicity moved eastward under this regime. Therefore, we should pay attention to the West Qinling Mountain area where an Ms6–7 earthquake could occur in future.

  11. Multiple tests for wind turbine fault detection and score fusion using two- level multidimensional scaling (MDS)

    Science.gov (United States)

    Ye, Xiang; Gao, Weihua; Yan, Yanjun; Osadciw, Lisa A.

    2010-04-01

    Wind is an important renewable energy source. The energy and economic return from building wind farms justify the expensive investments in doing so. However, without an effective monitoring system, underperforming or faulty turbines will cause a huge loss in revenue. Early detection of such failures help prevent these undesired working conditions. We develop three tests on power curve, rotor speed curve, pitch angle curve of individual turbine. In each test, multiple states are defined to distinguish different working conditions, including complete shut-downs, under-performing states, abnormally frequent default states, as well as normal working states. These three tests are combined to reach a final conclusion, which is more effective than any single test. Through extensive data mining of historical data and verification from farm operators, some state combinations are discovered to be strong indicators of spindle failures, lightning strikes, anemometer faults, etc, for fault detection. In each individual test, and in the score fusion of these tests, we apply multidimensional scaling (MDS) to reduce the high dimensional feature space into a 3-dimensional visualization, from which it is easier to discover turbine working information. This approach gains a qualitative understanding of turbine performance status to detect faults, and also provides explanations on what has happened for detailed diagnostics. The state-of-the-art SCADA (Supervisory Control And Data Acquisition) system in industry can only answer the question whether there are abnormal working states, and our evaluation of multiple states in multiple tests is also promising for diagnostics. In the future, these tests can be readily incorporated in a Bayesian network for intelligent analysis and decision support.

  12. A novel active T-type three-level converter with open-circuit fault-tolerant control

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede

    2015-01-01

    This paper proposes a novel active T-type three-level converter concept with fault-tolerant control. With the proposed topology, the converter can be operated continuously under open-circuit faults. It is shown that the proposed topology not only can keep its outputs under open-circuit fault cond...

  13. Implementation of fuzzy modeling system for faults detection and diagnosis in three phase induction motor drive system

    Directory of Open Access Journals (Sweden)

    Shorouk Ossama Ibrahim

    2015-05-01

    Full Text Available Induction motors have been intensively utilized in industrial applications, mainly due to their efficiency and reliability. It is necessary that these machines work all the time with its high performance and reliability. So it is necessary to monitor, detect and diagnose different faults that these motors are facing. In this paper an intelligent fault detection and diagnosis for different faults of induction motor drive system is introduced. The stator currents and the time are introduced as inputs to the proposed fuzzy detection and diagnosis system. The direct torque control technique (DTC is adopted as a suitable control technique in the drive system especially, in traction applications, such as Electric Vehicles and Sub-Way Metro that used such a machine. An intelligent modeling technique is adopted as an identifier for different faults; the proposed model introduces the time as an important factor or variable that plays an important role either in fault detection or in decision making for suitable corrective action according to the type of the fault. Experimental results have been obtained to verify the efficiency of the proposed intelligent detector and identifier; a matching between the simulated and experimental results has been noticed.

  14. Using recurrence plot analysis for software execution interpretation and fault detection

    Science.gov (United States)

    Mosdorf, M.

    2015-09-01

    This paper shows a method targeted at software execution interpretation and fault detection using recurrence plot analysis. In in the proposed approach recurrence plot analysis is applied to software execution trace that contains executed assembly instructions. Results of this analysis are subject to further processing with PCA (Principal Component Analysis) method that simplifies number coefficients used for software execution classification. This method was used for the analysis of five algorithms: Bubble Sort, Quick Sort, Median Filter, FIR, SHA-1. Results show that some of the collected traces could be easily assigned to particular algorithms (logs from Bubble Sort and FIR algorithms) while others are more difficult to distinguish.

  15. Model-based fault detection and identification with online aerodynamic model structure selection

    Science.gov (United States)

    Lombaerts, T.

    2013-12-01

    This publication describes a recursive algorithm for the approximation of time-varying nonlinear aerodynamic models by means of a joint adaptive selection of the model structure and parameter estimation. This procedure is called adaptive recursive orthogonal least squares (AROLS) and is an extension and modification of the previously developed ROLS procedure. This algorithm is particularly useful for model-based fault detection and identification (FDI) of aerospace systems. After the failure, a completely new aerodynamic model can be elaborated recursively with respect to structure as well as parameter values. The performance of the identification algorithm is demonstrated on a simulation data set.

  16. Support vector machine based fault detection approach for RFT-30 cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Young Bae, E-mail: ybkong@kaeri.re.kr; Lee, Eun Je; Hur, Min Goo; Park, Jeong Hoon; Park, Yong Dae; Yang, Seung Dae

    2016-10-21

    An RFT-30 is a 30 MeV cyclotron used for radioisotope applications and radiopharmaceutical researches. The RFT-30 cyclotron is highly complex and includes many signals for control and monitoring of the system. It is quite difficult to detect and monitor the system failure in real time. Moreover, continuous monitoring of the system is hard and time-consuming work for human operators. In this paper, we propose a support vector machine (SVM) based fault detection approach for the RFT-30 cyclotron. The proposed approach performs SVM learning with training samples to construct the classification model. To compensate the system complexity due to the large-scale accelerator, we utilize the principal component analysis (PCA) for transformation of the original data. After training procedure, the proposed approach detects the system faults in real time. We analyzed the performance of the proposed approach utilizing the experimental data of the RFT-30 cyclotron. The performance results show that the proposed SVM approach can provide an efficient way to control the cyclotron system.

  17. Micro-Raman spectroscopy for the detection of stacking fault density in InAs and GaAs nanowires

    Science.gov (United States)

    Tanta, Rawa; Lindberg, Caroline; Lehmann, Sebastian; Bolinsson, Jessica; Carro-Temboury, Miguel R.; Dick, Kimberly A.; Vosch, Tom; Jespersen, Thomas Sand; Nygârd, Jesper

    2017-10-01

    We investigate the relation between crystal stacking faults in individual wurtzite InAs and GaAs nanowires and the intensity of the forbidden longitudinal optical (LO) phonon mode in the Raman spectra. Micro-Raman spectroscopy and transmission electron microscopy are combined on the same individual nanowires to evaluate the LO mode intensity as a function of the stacking fault density. A clear increase in the LO mode intensity was observed when the stacking fault density was increased. Our results confirm the utility of Raman spectroscopy as a powerful tool for detecting crystal defects in nanowires.

  18. A Novel Method for Inverter Faults Detection and Diagnosis in PMSM Drives of HEVs based on Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    AKTAS, M.

    2012-11-01

    Full Text Available The paper proposes a novel method, based on wavelet decomposition, for detection and diagnosis of faults (switch short-circuits and switch open-circuits in the driving systems with Field Oriented Controlled Permanent Magnet Synchro?nous Motors (PMSM of Hybrid Electric Vehicles. The fault behaviour of the analyzed system was simulated by Matlab/SIMULINK R2010a. The stator currents during transients were analysed up to the sixth level detail wavelet decomposition by Symlet2 wavelet. The results prove that the proposed fault diagnosis system have very good capabilities.

  19. Fault detection and isolation of high temperature proton exchange membrane fuel cell stack under the influence of degradation

    DEFF Research Database (Denmark)

    Jeppesen, Christian; Araya, Samuel Simon; Sahlin, Simon Lennart

    2017-01-01

    This study proposes a data-drive impedance-based methodology for fault detection and isolation of low and high cathode stoichiometry, high CO concentration in the anode gas, high methanol vapour concentrations in the anode gas and low anode stoichiometry, for high temperature PEM fuel cells...... methanol vapour concentration in the anode gas fault, which was found to be difficult to distinguish from a normal operational data. The achieved accuracy for faults related to CO pollution, anode- and cathode stoichiometry is 100% success rate. Overall global accuracy on the test data is 94.6%....

  20. Evaluation of a dual processor implementation for a fault inferring nonlinear detection system

    Science.gov (United States)

    Godiwala, P. M.; Caglayan, A. K.; Morrell, F. R.

    1987-01-01

    The design of a modified fault inferring nonlinear detection system (FINDS) algorithm for a dual-processor configured flight computer is described. The algorithm was changed in order to divide it into its translational dynamics and rotational kinematics and to use it for parallel execution on the flight computer. The FINDS consists of: (1) a no-fail filter (NFF), (2) a set of test-of-mean detection tests, (3) a bank of first order filters to estimate failure levels in individual sensors, and (4) a decision function. NFF filter performance using flight recorded sensor data is analyzed using a filter autoinitialization routine. The failure detection and isolation capability of the partitioned algorithm is evaluated. A multirate implementation for the bias-free and bias filter gain and covariance matrices is discussed.

  1. Compound faults detection of rolling element bearing based on the generalized demodulation algorithm under time-varying rotational speed

    Science.gov (United States)

    Zhao, Dezun; Li, Jianyong; Cheng, Weidong; Wen, Weigang

    2016-09-01

    Multi-fault detection of the rolling element bearing under time-varying rotational speed presents a challenging issue due to its complexity, disproportion and interaction. Computed order analysis (COA) is one of the most effective approaches to remove the influences of speed fluctuation, and detect all the features of multi-fault. However, many interference components in the envelope order spectrum may lead to false diagnosis results, in addition, the deficiencies of computational accuracy and efficiency also cannot be neglected. To address these issues, a novel method for compound faults detection of rolling element bearing based on the generalized demodulation (GD) algorithm is proposed in this paper. The main idea of the proposed method is to exploit the unique property of the generalized demodulation algorithm in transforming an interested instantaneous frequency trajectory of compound faults bearing signal into a line paralleling to the time axis, and then the FFT algorithm can be directly applied to the transformed signal. This novel method does not need angular resampling algorithm which is the key step of the computed order analysis, and is hence free from the deficiencies of computational error and efficiency. On the other hand, it only acts on the instantaneous fault characteristic frequency trends in envelope signal of multi-fault bearing which include rich fault information, and is hence free from irrelevant items interferences. Both simulated and experimental faulty bearing signal analysis validate that the proposed method is effective and reliable on the compound faults detection of rolling element bearing under variable rotational speed conditions. The comprehensive comparison with the computed order analysis further shows that the proposed method produces higher accurate results in less computation time.

  2. Contradicting Estimates of Location, Geometry, and Rupture History of Highly Active Faults in Central Japan

    Science.gov (United States)

    Okumura, K.

    2011-12-01

    Accurate location and geometry of seismic sources are critical to estimate strong ground motion. Complete and precise rupture history is also critical to estimate the probability of the future events. In order to better forecast future earthquakes and to reduce seismic hazards, we should consider over all options and choose the most likely parameter. Multiple options for logic trees are acceptable only after thorough examination of contradicting estimates and should not be a result from easy compromise or epoche. In the process of preparation and revisions of Japanese probabilistic and deterministic earthquake hazard maps by Headquarters for Earthquake Research Promotion since 1996, many decisions were made to select plausible parameters, but many contradicting estimates have been left without thorough examinations. There are several highly-active faults in central Japan such as Itoigawa-Shizuoka Tectonic Line active fault system (ISTL), West Nagano Basin fault system (WNBF), Inadani fault system (INFS), and Atera fault system (ATFS). The highest slip rate and the shortest recurrence interval are respectively ~1 cm/yr and 500 to 800 years, and estimated maximum magnitude is 7.5 to 8.5. Those faults are very hazardous because almost entire population and industries are located above the fault within tectonic depressions. As to the fault location, most uncertainties arises from interpretation of geomorphic features. Geomorphological interpretation without geological and structural insight often leads to wrong mapping. Though non-existent longer fault may be a safer estimate, incorrectness harm reliability of the forecast. Also this does not greatly affect strong motion estimates, but misleading to surface displacement issues. Fault geometry, on the other hand, is very important to estimate intensity distribution. For the middle portion of the ISTL, fast-moving left-lateral strike-slip up to 1 cm/yr is obvious. Recent seismicity possibly induced by 2011 Tohoku

  3. Near-Surface Seismic Profiling Across the Active Carlsberg Fault, Denmark

    Science.gov (United States)

    Jorgensen, M. I.; Nielsen, L.; Fallesen, J.; Thybo, H.

    2002-12-01

    An integrated near-surface normal-incidence and wide-angle seismic experiment has been conducted across the active Carlsberg Fault in the easternmost part of the Danish basin, just east of Copenhagen. The purpose of the seismic experiment is to: 1) determine the fault structure; 2) image possible seismic velocity contrasts across the fault; and 3) estimate how much the fault offsets the individual sedimentary layers at the different depth levels. The origin of the Carlsberg Fault is probably related to extensional stresses in a strike-slip system caused by movements in the Sorgenfrei-Tornquist Zone, which is a 20-50 km wide fault zone located approximately 50 km east of Copenhagen. In the study area, the upper sedimentary strata consist of Cretaceous and Danian chalk layers as well as younger sediments, which predominantly consist of sand and clay. The fault runs in an overall NNW-SSE direction, and it penetrates the various sedimentary strata. Geodetic measurements show that the fault has been active within the last 100 years. The normal-incidence data were collected along an 1100 m long line perpendicular to the strike of the fault with a shot spacing of 12 m and a receiver spacing of 6 m. The reflection image reveals a clear flower structure in the upper 400 ms of the section indicating that substantial horizontal movement has taken place along the Carlsberg Fault. This flower structure is relatively narrow at 350 ms depth, whereas it unfolds to a width of about 300 m in the uppermost layers. The wide-angle data were collected along a 2000 m long line with shot and receiver spacings of 100 m and 10 m, respectively. They provide good velocity control of the sedimentary layers and allow for depth conversion of the reflection seismic image. Furthermore the wide-angle data have the potential of providing back-scattered reflections from the fault planes. GPR measurements have been planned in order to constrain the very shallow and recent movements along the fault.

  4. Special research laboratory for active fault and earthquake prediction (1997): main results of active fault research in 1996 fiscal year; 1996 nendo ni jisshishita katsudanso chosa no seika gaiyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    The paper outlined the active fault survey made in fiscal 1996 as a special research of Agency of Industrial Science and Technology. Active faults in the Kinki delta zone were mainly surveyed in the researches `the pre-survey of geological structures, etc. for active fault survey (contract research with Osaka Soil Test)` in fiscal 1995 and `the study of a potentiality of earthquakes caused by active faults (special research of Agency of Industrial Science and Technology)` in fiscal 1996. In the contract research in fiscal 1995, topography/geology survey, boring survey and geophysical exploration were conducted as pre-survey for eight active faults in the Kinki delta zone, Tsuruga, Hanaori, west of Lake Biwa, Ikoma, east edge of Nara Basin, Kongou, Chuo Tectonic Line, and Kuwana. Following the pre-survey, made in fiscal 1996 were trench surveys of five faults, Hanaori, west of Lake Biwa, Ikoma, east edge of Nara Basin and Kongou. Further, following fiscal 1995, as a survey of active faults existing under the plain of a big city, etc., a survey was conducted of the reflection method survey of the Uemachi Fault System of Osaka. Besides, as a supplementary survey for important active faults, carried out were trench surveys of the Itoigawa-Shizuoka Techtonic Line and the Kouzu-Matsuda Fault. 25 refs., 11 figs.

  5. Multipoint Optimal Minimum Entropy Deconvolution and Convolution Fix: Application to vibration fault detection

    Science.gov (United States)

    McDonald, Geoff L.; Zhao, Qing

    2017-01-01

    Minimum Entropy Deconvolution (MED) has been applied successfully to rotating machine fault detection from vibration data, however this method has limitations. A convolution adjustment to the MED definition and solution is proposed in this paper to address the discontinuity at the start of the signal - in some cases causing spurious impulses to be erroneously deconvolved. A problem with the MED solution is that it is an iterative selection process, and will not necessarily design an optimal filter for the posed problem. Additionally, the problem goal in MED prefers to deconvolve a single-impulse, while in rotating machine faults we expect one impulse-like vibration source per rotational period of the faulty element. Maximum Correlated Kurtosis Deconvolution was proposed to address some of these problems, and although it solves the target goal of multiple periodic impulses, it is still an iterative non-optimal solution to the posed problem and only solves for a limited set of impulses in a row. Ideally, the problem goal should target an impulse train as the output goal, and should directly solve for the optimal filter in a non-iterative manner. To meet these goals, we propose a non-iterative deconvolution approach called Multipoint Optimal Minimum Entropy Deconvolution Adjusted (MOMEDA). MOMEDA proposes a deconvolution problem with an infinite impulse train as the goal and the optimal filter solution can be solved for directly. From experimental data on a gearbox with and without a gear tooth chip, we show that MOMEDA and its deconvolution spectrums according to the period between the impulses can be used to detect faults and study the health of rotating machine elements effectively.

  6. Active fault tolerant control based on interval type-2 fuzzy sliding mode controller and non linear adaptive observer for 3-DOF laboratory helicopter.

    Science.gov (United States)

    Zeghlache, Samir; Benslimane, Tarak; Bouguerra, Abderrahmen

    2017-11-01

    In this paper, a robust controller for a three degree of freedom (3 DOF) helicopter control is proposed in presence of actuator and sensor faults. For this purpose, Interval type-2 fuzzy logic control approach (IT2FLC) and sliding mode control (SMC) technique are used to design a controller, named active fault tolerant interval type-2 Fuzzy Sliding mode controller (AFTIT2FSMC) based on non-linear adaptive observer to estimate and detect the system faults for each subsystem of the 3-DOF helicopter. The proposed control scheme allows avoiding difficult modeling, attenuating the chattering effect of the SMC, reducing the rules number of the fuzzy controller. Exponential stability of the closed loop is guaranteed by using the Lyapunov method. The simulation results show that the AFTIT2FSMC can greatly alleviate the chattering effect, providing good tracking performance, even in presence of actuator and sensor faults. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Comparative Study of Time-Frequency Decomposition Techniques for Fault Detection in Induction Motors Using Vibration Analysis during Startup Transient

    Directory of Open Access Journals (Sweden)

    Paulo Antonio Delgado-Arredondo

    2015-01-01

    Full Text Available Induction motors are critical components for most industries and the condition monitoring has become necessary to detect faults. There are several techniques for fault diagnosis of induction motors and analyzing the startup transient vibration signals is not as widely used as other techniques like motor current signature analysis. Vibration analysis gives a fault diagnosis focused on the location of spectral components associated with faults. Therefore, this paper presents a comparative study of different time-frequency analysis methodologies that can be used for detecting faults in induction motors analyzing vibration signals during the startup transient. The studied methodologies are the time-frequency distribution of Gabor (TFDG, the time-frequency Morlet scalogram (TFMS, multiple signal classification (MUSIC, and fast Fourier transform (FFT. The analyzed vibration signals are one broken rotor bar, two broken bars, unbalance, and bearing defects. The obtained results have shown the feasibility of detecting faults in induction motors using the time-frequency spectral analysis applied to vibration signals, and the proposed methodology is applicable when it does not have current signals and only has vibration signals. Also, the methodology has applications in motors that are not fed directly to the supply line, in such cases the analysis of current signals is not recommended due to poor current signal quality.

  8. Fault detection in rotating machines with beamforming: Spatial visualization of diagnosis features

    Science.gov (United States)

    Cardenas Cabada, E.; Leclere, Q.; Antoni, J.; Hamzaoui, N.

    2017-12-01

    Rotating machines diagnosis is conventionally related to vibration analysis. Sensors are usually placed on the machine to gather information about its components. The recorded signals are then processed through a fault detection algorithm allowing the identification of the failing part. This paper proposes an acoustic-based diagnosis method. A microphone array is used to record the acoustic field radiated by the machine. The main advantage over vibration-based diagnosis is that the contact between the sensors and the machine is no longer required. Moreover, the application of acoustic imaging makes possible the identification of the sources of acoustic radiation on the machine surface. The display of information is then spatially continuous while the accelerometers only give it discrete. Beamforming provides the time-varying signals radiated by the machine as a function of space. Any fault detection tool can be applied to the beamforming output. Spectral kurtosis, which highlights the impulsiveness of a signal as function of frequency, is used in this study. The combination of spectral kurtosis with acoustic imaging makes possible the mapping of the impulsiveness as a function of space and frequency. The efficiency of this approach lays on the source separation in the spatial and frequency domains. These mappings make possible the localization of such impulsive sources. The faulty components of the machine have an impulsive behavior and thus will be highlighted on the mappings. The study presents experimental validations of the method on rotating machines.

  9. Agent-based algorithm for fault detection and recovery of gyroscope's drift in small satellite missions

    Science.gov (United States)

    Carvajal-Godinez, Johan; Guo, Jian; Gill, Eberhard

    2017-10-01

    Failure detection, isolation, and recovery is an essential requirement of any space mission design. Several spacecraft components, especially sensors, are prone to performance deviation due to intrinsic physical effects. For that reason, innovative approaches for the treatment of faults in onboard sensors are necessary. This work introduces the concept of agent-based fault detection and recovery for sensors used in satellite attitude determination and control. Its focuses on the implementation of an algorithm for addressing linear drift bias in gyroscopes. The algorithm was implemented using an agent-based architecture that can be integrated into the satellite's onboard software. Numerical simulations were carried out to show the effectiveness of this scheme in satellite's operations. The proposed algorithm showed a reduction of up to 50% in the stabilization time for the detumbling maneuver, and also an improvement in the pointing accuracy of up to 20% when it was applied in precise payload pointing procedures. The relevance of this contribution is its added value for optimizing the launch and early operation of small satellite missions, as well as, an enabler for innovative satellite functions, for instance, optical downlink communication.

  10. A Virtual Sensor for Online Fault Detection of Multitooth-Tools

    Directory of Open Access Journals (Sweden)

    Andres Bustillo

    2011-03-01

    Full Text Available The installation of suitable sensors close to the tool tip on milling centres is not possible in industrial environments. It is therefore necessary to design virtual sensors for these machines to perform online fault detection in many industrial tasks. This paper presents a virtual sensor for online fault detection of multitooth tools based on a Bayesian classifier. The device that performs this task applies mathematical models that function in conjunction with physical sensors. Only two experimental variables are collected from the milling centre that performs the machining operations: the electrical power consumption of the feed drive and the time required for machining each workpiece. The task of achieving reliable signals from a milling process is especially complex when multitooth tools are used, because each kind of cutting insert in the milling centre only works on each workpiece during a certain time window. Great effort has gone into designing a robust virtual sensor that can avoid re-calibration due to, e.g., maintenance operations. The virtual sensor developed as a result of this research is successfully validated under real conditions on a milling centre used for the mass production of automobile engine crankshafts. Recognition accuracy, calculated with a k-fold cross validation, had on average 0.957 of true positives and 0.986 of true negatives. Moreover, measured accuracy was 98%, which suggests that the virtual sensor correctly identifies new cases.

  11. A Virtual Sensor for Online Fault Detection of Multitooth-Tools

    Science.gov (United States)

    Bustillo, Andres; Correa, Maritza; Reñones, Anibal

    2011-01-01

    The installation of suitable sensors close to the tool tip on milling centres is not possible in industrial environments. It is therefore necessary to design virtual sensors for these machines to perform online fault detection in many industrial tasks. This paper presents a virtual sensor for online fault detection of multitooth tools based on a Bayesian classifier. The device that performs this task applies mathematical models that function in conjunction with physical sensors. Only two experimental variables are collected from the milling centre that performs the machining operations: the electrical power consumption of the feed drive and the time required for machining each workpiece. The task of achieving reliable signals from a milling process is especially complex when multitooth tools are used, because each kind of cutting insert in the milling centre only works on each workpiece during a certain time window. Great effort has gone into designing a robust virtual sensor that can avoid re-calibration due to, e.g., maintenance operations. The virtual sensor developed as a result of this research is successfully validated under real conditions on a milling centre used for the mass production of automobile engine crankshafts. Recognition accuracy, calculated with a k-fold cross validation, had on average 0.957 of true positives and 0.986 of true negatives. Moreover, measured accuracy was 98%, which suggests that the virtual sensor correctly identifies new cases. PMID:22163766

  12. Fault detection of flywheel system based on clustering and principal component analysis

    Directory of Open Access Journals (Sweden)

    Wang Rixin

    2015-12-01

    Full Text Available Considering the nonlinear, multifunctional properties of double-flywheel with closed-loop control, a two-step method including clustering and principal component analysis is proposed to detect the two faults in the multifunctional flywheels. At the first step of the proposed algorithm, clustering is taken as feature recognition to check the instructions of “integrated power and attitude control” system, such as attitude control, energy storage or energy discharge. These commands will ask the flywheel system to work in different operation modes. Therefore, the relationship of parameters in different operations can define the cluster structure of training data. Ordering points to identify the clustering structure (OPTICS can automatically identify these clusters by the reachability-plot. K-means algorithm can divide the training data into the corresponding operations according to the reachability-plot. Finally, the last step of proposed model is used to define the relationship of parameters in each operation through the principal component analysis (PCA method. Compared with the PCA model, the proposed approach is capable of identifying the new clusters and learning the new behavior of incoming data. The simulation results show that it can effectively detect the faults in the multifunctional flywheels system.

  13. Fault Detection In Manufacturing Cells Based On Three-Dimensional Visual Information

    Science.gov (United States)

    Bourne, David A.; Milligan, Robert; Wright, Paul K.

    1982-11-01

    A three dimensional representation of a part is reconstructed from multiple camera views. Measurements are then collected from this three dimensional data and can be used to detect faults in the manufacturing process. The manufacturing faults are detected as visual abnormalities in the final parts. These abnormalities correspond to error conditions in earlier phases of manufacturing and could represent equipment failure, equipment wear or the use of a faulty control algorithm. A gage station which collects visual information is discussed. The algorithm which converts the visual information into a three dimensional representation of the part is presented and compared to other similar reconstruction strategies. Once the data have been collected and reconstructed, measurements are taken and correlated with possible error conditions. New correlations between the part measurements and manufacturing errors can be added to the control system as problems occur. For example, hammer wear in an open-die forge can be discovered by measuring the length of a work piece after it was struck. Along with each casual relationship there is a suggested course of action which is intended to be an immediate remedy for the error condition. In the forge example, a simple corrective action would be to move the hammers closer together to account for their wear. This makes it possible for the overall system to approach immunity to catastrophic errors while minimizing the number of defective parts.

  14. Natural Radiation for Identification and Evaluation of Risk Zones for Affectation of Activated Faults in Aquifer Overexploited.

    Science.gov (United States)

    Ramos-Leal, J.; Lopez-Loera, H.; Carbajal-Perez, N.

    2007-05-01

    In basins as Mexico, Michoacán, Guanajuato, Queretaro, Aguascalientes and San Luis Potosi, the existence of faults and fractures have affected the urban infrastructure, lines of conduction of drinkable water, pipelines, etc., that when not being identified and considered, they don't reflect the real impact that these cause also to the aquifer system, modifying the permeability of the means and in occasions they work as preferential conduits that communicate hydraulically potentially to the aquifer with substances pollutants (metals, fertilizers, hydrocarbons, waste waters, etc.) located in the surface. In the Valley of San Luis Potosi, Villa of Reyes, Arista, Ahualulco and recently The Huizache-Matehuala is being strongly affected by faulting and supposedly due cracking to subsidence, however, the regional tectonic could also be the origin of this phenomenon. To know the origin of the faults and affectation to the vulnerability of the aquifer few works they have been carried out in the area. A preliminary analysis indicates that it is possible that a tectonic component is affecting the area and that the vulnerability of the aquifer in that area you this increasing. Before such a situation, it is necessary to carry out the isotopic study of the same one, for this way to know among other things, isotopic characterization, recharge places and addresses of flow of the groundwater; quality of waters and the behavior hydrochemistry with relationship to the faults. High radon values were measured in San Luis Potosi Valley, the natural source of radon could be the riolites and however, these are located to almost a once thousand meters deep for what the migration of the gas is not very probable. The anomalies radiometrics was not correlation with the faults in this case. In some areas like the Valley of Celaya, the origin of the structures and the tectonic activity in the area was confirmed, identifying the structural arrangement of the faulting, the space relationships

  15. Active faults paragenesis and the state of crustal stresses in the Late Cenozoic in Central Mongolia

    Directory of Open Access Journals (Sweden)

    V. A. Sankov

    2015-01-01

    Full Text Available Active faults of the Hangay-Hentiy tectonic saddle region in Central Mongolia are studied by space images interpretation, relief analysis, structural methods and tectonic stress reconstruction. The study results show that faults activation during the Late Cenozoic stage was selective, and a cluster pattern of active faults is typical for the study region. Morphological and genetic types and the kinematics of faults in the Hangay-Hentiy saddle region are related the direction of the ancient inherited structural heterogeneities. Latitudinal and WNW trending faults are left lateral strike-slips with reverse or thrust component (Dzhargalantgol and North Burd faults. NW trending faults are reverse faults or thrusts with left lateral horizontal component. NNW trending faults have right lateral horizontal component. The horizontal component of the displacements, as a rule, exceeds the vertical one. Brittle deformations in fault zones do not conform with the Pliocene and, for the most part, Pleistocene topography. With some caution it may be concluded that the last phase of revitalization of strike slip and reverse movements along the faults commenced in the Late Pleistocene. NE trending disjunctives are normal faults distributed mainly within the Hangay uplift. Their features are more early activation within the Late Cenozoic and the lack of relation to large linear structures of the previous tectonic stages. According to the stress tensor reconstructions of the last phase of deformation in zones of active faults of the Hangay-Hentiy saddle using data on tectonic fractures and fault displacements, it is revealed that conditions of compression and strike-slip with NNE direction of the axis of maximum compression were dominant. Stress tensors of extensional type with NNW direction of minimum compression are reconstructed for the Orkhon graben. It is concluded that the activation of faults in Central Mongolia in the Pleistocene-Holocene, as well as

  16. Active faults paragenesis and the state of crustal stresses in the Late Cenozoic in Central Mongolia

    Directory of Open Access Journals (Sweden)

    V. A. Sankov

    2015-12-01

    Full Text Available Active faults of the Hangay-Hentiy tectonic saddle region in Central Mongolia are studied by space images interpretation, relief analysis, structural methods and tectonic stress reconstruction. The study results show that faults activation during the Late Cenozoic stage was selective, and a cluster pattern of active faults is typical for the study region. Morphological and genetic types and the kinematics of faults in the Hangay-Hentiy saddle region are related the direction of the ancient inherited structural heterogeneities. Latitudinal and WNW trending faults are left lateral strike-slips with reverse or thrust component (Dzhargalantgol and North Burd faults. NW trending faults are reverse faults or thrusts with left lateral horizontal component. NNW trending faults have right lateral horizontal component. The horizontal component of the displacements, as a rule, exceeds the vertical one. Brittle deformations in fault zones do not conform with the Pliocene and, for the most part, Pleistocene topography. With some caution it may be concluded that the last phase of revitalization of strike slip and reverse movements along the faults commenced in the Late Pleistocene. NE trending disjunctives are normal faults distributed mainly within the Hangay uplift. Their features are more early activation within the Late Cenozoic and the lack of relation to large linear structures of the previous tectonic stages. According to the stress tensor reconstructions of the last phase of deformation in zones of active faults of the Hangay-Hentiy saddle using data on tectonic fractures and fault displacements, it is revealed that conditions of compression and strike-slip with NNE direction of the axis of maximum compression were dominant. Stress tensors of extensional type with NNW direction of minimum compression are reconstructed for the Orkhon graben. It is concluded that the activation of faults in Central Mongolia in the Pleistocene-Holocene, as well as

  17. One of the proposals to estimation of the active fault with the flexure structure

    Science.gov (United States)

    Kitada, N.; Takemura, K.

    2010-12-01

    In general, the recurrent interval investigation that uses the trench excavation survey etc. is done to the active fault survey. However, even if form of the search procedure of the active fault where the surface part is flexure structure is understood, it is difficult to understand the detailed activity situation. The active fault survey is done by the sedimentary environment of the investigation site, and an efficient search procedure is different. However, the recurrent interval of the fault with the flexure structure should devise it more. In the present study, two illustrations of the examination case with the active fault with the flexure structure. Osaka bay fault has the flexure structure, and the latest activity is not understood well though many reflection surveys have done. Then, flexure was stepped over and the drilling survey was carried out. It consists of the alluvium marine clay in the surface part compared the change in the amount of piling up by measuring at magnetostratigraphical measurement and a radio carbon age etc., and correlates between up side and down side homogeneous clay layer. As a result, the appearance with a greatly different inclination was confirmed between the boring of both who seemed that the same environments it though the correlation line was basically compared by the same inclination. When the alluvium piles up, such a change point is three times. The change was seen at the rate once every about 2000-3000 years and about 0.58m/ka when putting it together on the result of the age determination. The Uemachi fault is a fault in the south north that passes as for the central area of Osaka. The up side on the fault is modified by erosion and urban development, and one of the faults that a recurrent interval is cramped. Moreover, the surface part is flexure structure in this fault according to the reflection survey. To forecast a long term for the seismic design when the subway in this part was constructed, the drilling survey of

  18. Lessons Learned on Implementing Fault Detection, Isolation, and Recovery (FDIR) in a Ground Launch Environment

    Science.gov (United States)

    Ferrell, Bob A.; Lewis, Mark E.; Perotti, Jose M.; Brown, Barbara L.; Oostdyk, Rebecca L.; Goetz, Jesse W.

    2010-01-01

    This paper's main purpose is to detail issues and lessons learned regarding designing, integrating, and implementing Fault Detection Isolation and Recovery (FDIR) for Constellation Exploration Program (CxP) Ground Operations at Kennedy Space Center (KSC). Part of the0 overall implementation of National Aeronautics and Space Administration's (NASA's) CxP, FDIR is being implemented in three main components of the program (Ares, Orion, and Ground Operations/Processing). While not initially part of the design baseline for the CxP Ground Operations, NASA felt that FDIR is important enough to develop, that NASA's Exploration Systems Mission Directorate's (ESMD's) Exploration Technology Development Program (ETDP) initiated a task for it under their Integrated System Health Management (ISHM) research area. This task, referred to as the FDIIR project, is a multi-year multi-center effort. The primary purpose of the FDIR project is to develop a prototype and pathway upon which Fault Detection and Isolation (FDI) may be transitioned into the Ground Operations baseline. Currently, Qualtech Systems Inc (QSI) Commercial Off The Shelf (COTS) software products Testability Engineering and Maintenance System (TEAMS) Designer and TEAMS RDS/RT are being utilized in the implementation of FDI within the FDIR project. The TEAMS Designer COTS software product is being utilized to model the system with Functional Fault Models (FFMs). A limited set of systems in Ground Operations are being modeled by the FDIR project, and the entire Ares Launch Vehicle is being modeled under the Functional Fault Analysis (FFA) project at Marshall Space Flight Center (MSFC). Integration of the Ares FFMs and the Ground Processing FFMs is being done under the FDIR project also utilizing the TEAMS Designer COTS software product. One of the most significant challenges related to integration is to ensure that FFMs developed by different organizations can be integrated easily and without errors. Software Interface

  19. Early Oscillation Detection for Hybrid DC/DC Converter Fault Diagnosis

    Science.gov (United States)

    Wang, Bright L.

    2011-01-01

    This paper describes a novel fault detection technique for hybrid DC/DC converter oscillation diagnosis. The technique is based on principles of feedback control loop oscillation and RF signal modulations, and Is realized by using signal spectral analysis. Real-circuit simulation and analytical study reveal critical factors of the oscillation and indicate significant correlations between the spectral analysis method and the gain/phase margin method. A stability diagnosis index (SDI) is developed as a quantitative measure to accurately assign a degree of stability to the DC/DC converter. This technique Is capable of detecting oscillation at an early stage without interfering with DC/DC converter's normal operation and without limitations of probing to the converter.

  20. Influence of magnetic saturation effects on the fault detection of induction motors

    Directory of Open Access Journals (Sweden)

    Drozdowski Piotr

    2014-09-01

    Full Text Available In this paper, the influence of impact damage to the induction motors on the zero-sequence voltage and its spectrum is presented. The signals detecting the damages result from a detailed analysis of the formula describing this voltage component which is induced in the stator windings due to core magnetic saturation and the discrete displacement of windings. Its course is affected by the operation of both the stator and the rotor. Other fault detection methods, are known and widely applied by analysing the spectrum of stator currents. The presented method may be a complement to other methods because of the ease of measurements of the zero voltage for star connected motors. Additionally, for converter fed motors the zero sequence voltage eliminates higher time harmonics displaced by 120 degrees. The results of the method application are presented through measurements and explained by the use of a mathematical model of the slip-ring induction motor

  1. Active fault systems and their significance for urban planning in Bucharest, Romania

    Science.gov (United States)

    Ioane, Dumitru; Stanciucu, Mihaela; Chitea, Florina; Diaconescu, Mihail

    2010-05-01

    Active fault systems may have significant influences in slow ground displacements during neotectonic vertical or/and horizontal movements, or sudden ones, as a consequence of high magnitude earthquakes. In urban planning activities, besides a detailed seismic zonation, the areal distribution of active faults and particularly of fault crossing sectors may be valuable in numerous cases. In large cities as Bucharest, Romania, built over quite thick sequences of Quaternary unconsolidated sediments, there were no possibilities of geologically mapping faults or fault systems, the geological structures being deeply buried. Due to their specific structure, the unconsolidated sediments do not preserve traces of active faulting, either due to neotectonic processes or seismic events. In the geotechnical and hydrogeological wells and in the subway tunnels such tectonic elements are not easily observed by specialists, the resulted geological cross sections representing many times only facies changes and no faults. Geophysical measurements (reflection seismics, gravity, vertical electric soundings, magnetics) or seismological observations of seismic events with Richter magnitude greater than 2, may be of greater utility, even they were not generally carried out so far at appropriate detailed scales. This preliminary study employed existing geophysical data and recordings on the local seismicity, correlated with geomorphological, geological and tectonic information related to a larger area that includes the city of Bucharest. The existing tectonic data related to fault systems refer to deeper ones, previously illustrated by 2D reflection seismic measurements performed for oil and gas accumulations. The main fault systems crossing Bucharest are trending NW-SE and N-S, directions that are also imprinted in the hydrological network: Dambovita and Colentina rivers, and a Colentina tributary trending northward, respectively. The NE-SW trending system, characteristic to the Vrancea

  2. Short-Circuit Fault Detection and Classification Using Empirical Wavelet Transform and Local Energy for Electric Transmission Line.

    Science.gov (United States)

    Huang, Nantian; Qi, Jiajin; Li, Fuqing; Yang, Dongfeng; Cai, Guowei; Huang, Guilin; Zheng, Jian; Li, Zhenxin

    2017-09-16

    In order to improve the classification accuracy of recognizing short-circuit faults in electric transmission lines, a novel detection and diagnosis method based on empirical wavelet transform (EWT) and local energy (LE) is proposed. First, EWT is used to deal with the original short-circuit fault signals from photoelectric voltage transformers, before the amplitude modulated-frequency modulated (AM-FM) mode with a compactly supported Fourier spectrum is extracted. Subsequently, the fault occurrence time is detected according to the modulus maxima of intrinsic mode function (IMF₂) from three-phase voltage signals processed by EWT. After this process, the feature vectors are constructed by calculating the LE of the fundamental frequency based on the three-phase voltage signals of one period after the fault occurred. Finally, the classifier based on support vector machine (SVM) which was constructed with the LE feature vectors is used to classify 10 types of short-circuit fault signals. Compared with complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and improved CEEMDAN methods, the new method using EWT has a better ability to present the frequency in time. The difference in the characteristics of the energy distribution in the time domain between different types of short-circuit faults can be presented by the feature vectors of LE. Together, simulation and real signals experiment demonstrate the validity and effectiveness of the new approach.

  3. Short-Circuit Fault Detection and Classification Using Empirical Wavelet Transform and Local Energy for Electric Transmission Line

    Directory of Open Access Journals (Sweden)

    Nantian Huang

    2017-09-01

    Full Text Available In order to improve the classification accuracy of recognizing short-circuit faults in electric transmission lines, a novel detection and diagnosis method based on empirical wavelet transform (EWT and local energy (LE is proposed. First, EWT is used to deal with the original short-circuit fault signals from photoelectric voltage transformers, before the amplitude modulated-frequency modulated (AM-FM mode with a compactly supported Fourier spectrum is extracted. Subsequently, the fault occurrence time is detected according to the modulus maxima of intrinsic mode function (IMF2 from three-phase voltage signals processed by EWT. After this process, the feature vectors are constructed by calculating the LE of the fundamental frequency based on the three-phase voltage signals of one period after the fault occurred. Finally, the classifier based on support vector machine (SVM which was constructed with the LE feature vectors is used to classify 10 types of short-circuit fault signals. Compared with complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN and improved CEEMDAN methods, the new method using EWT has a better ability to present the frequency in time. The difference in the characteristics of the energy distribution in the time domain between different types of short-circuit faults can be presented by the feature vectors of LE. Together, simulation and real signals experiment demonstrate the validity and effectiveness of the new approach.

  4. Short-Circuit Fault Detection and Classification Using Empirical Wavelet Transform and Local Energy for Electric Transmission Line

    Science.gov (United States)

    Huang, Nantian; Qi, Jiajin; Li, Fuqing; Yang, Dongfeng; Cai, Guowei; Huang, Guilin; Zheng, Jian; Li, Zhenxin

    2017-01-01

    In order to improve the classification accuracy of recognizing short-circuit faults in electric transmission lines, a novel detection and diagnosis method based on empirical wavelet transform (EWT) and local energy (LE) is proposed. First, EWT is used to deal with the original short-circuit fault signals from photoelectric voltage transformers, before the amplitude modulated-frequency modulated (AM-FM) mode with a compactly supported Fourier spectrum is extracted. Subsequently, the fault occurrence time is detected according to the modulus maxima of intrinsic mode function (IMF2) from three-phase voltage signals processed by EWT. After this process, the feature vectors are constructed by calculating the LE of the fundamental frequency based on the three-phase voltage signals of one period after the fault occurred. Finally, the classifier based on support vector machine (SVM) which was constructed with the LE feature vectors is used to classify 10 types of short-circuit fault signals. Compared with complementary ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and improved CEEMDAN methods, the new method using EWT has a better ability to present the frequency in time. The difference in the characteristics of the energy distribution in the time domain between different types of short-circuit faults can be presented by the feature vectors of LE. Together, simulation and real signals experiment demonstrate the validity and effectiveness of the new approach. PMID:28926953

  5. Open-Switch Fault Detection Method of a Back-to-Back Converter Using NPC Topology for Wind Turbine Systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Lee, Kyo_Beum; Blaabjerg, Frede

    2015-01-01

    In wind turbine generation (WTG) systems, a back-to-back converter with a neutral-point-clamped (NPC) topology is widely used because this topology has more advantages than a conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology....... An open-switch fault in the NPC rectifier of the back-to-back converter leads to the distortion of the input current and torque vibration in the system. Additionally, an open-switch fault in the NPC inverter of the back-to-back converter causes the distortion of the output current. Furthermore, the WTG...... system can break down in the worst case scenario. To improve the reliability of WTG systems, an open-switch fault detection method for back-to-back converters using the NPC topology is required. This study analyzes effects of inner and outer open-switch faults of the NPC rectifier and inverter...

  6. Analytic Confusion Matrix Bounds for Fault Detection and Isolation Using a Sum-of-Squared- Residuals Approach

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2009-01-01

    Given a system which can fail in 1 or n different ways, a fault detection and isolation (FDI) algorithm uses sensor data in order to determine which fault is the most likely to have occurred. The effectiveness of an FDI algorithm can be quantified by a confusion matrix, which i ndicates the probability that each fault is isolated given that each fault has occurred. Confusion matrices are often generated with simulation data, particularly for complex systems. In this paper we perform FDI using sums of squares of sensor residuals (SSRs). We assume that the sensor residuals are Gaussian, which gives the SSRs a chi-squared distribution. We then generate analytic lower and upper bounds on the confusion matrix elements. This allows for the generation of optimal sensor sets without numerical simulations. The confusion matrix bound s are verified with simulated aircraft engine data.

  7. Online Fault Detection of Permanent Magnet Demagnetization for IPMSMs by Nonsingular Fast Terminal-Sliding-Mode Observer

    Directory of Open Access Journals (Sweden)

    Kai-Hui Zhao

    2014-12-01

    Full Text Available To prevent irreversible demagnetization of a permanent magnet (PM for interior permanent magnet synchronous motors (IPMSMs by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LABplatform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance.

  8. Online Fault Detection of Permanent Magnet Demagnetization for IPMSMs by Nonsingular Fast Terminal-Sliding-Mode Observer

    Science.gov (United States)

    Zhao, Kai-Hui; Chen, Te-Fang; Zhang, Chang-Fan; He, Jing; Huang, Gang

    2014-01-01

    To prevent irreversible demagnetization of a permanent magnet (PM) for interior permanent magnet synchronous motors (IPMSMs) by flux-weakening control, a robust PM flux-linkage nonsingular fast terminal-sliding-mode observer (NFTSMO) is proposed to detect demagnetization faults. First, the IPMSM mathematical model of demagnetization is presented. Second, the construction of the NFTSMO to estimate PM demagnetization faults in IPMSM is described, and a proof of observer stability is given. The fault decision criteria and fault-processing method are also presented. Finally, the proposed scheme was simulated using MATLAB/Simulink and implemented on the RT-LAB platform. A number of robustness tests have been carried out. The scheme shows good performance in spite of speed fluctuations, torque ripples and the uncertainties of stator resistance. PMID:25490582

  9. On-Line Fault Detection in Wind Turbine Transmission System using Adaptive Filter and Robust Statistical Features

    Directory of Open Access Journals (Sweden)

    Mark Frogley

    2013-01-01

    Full Text Available To reduce the maintenance cost, avoid catastrophic failure, and improve the wind transmission system reliability, online condition monitoring system is critical important. In the real applications, many rotating mechanical faults, such as bearing surface defect, gear tooth crack, chipped gear tooth and so on generate impulsive signals. When there are these types of faults developing inside rotating machinery, each time the rotating components pass over the damage point, an impact force could be generated. The impact force will cause a ringing of the support structure at the structural natural frequency. By effectively detecting those periodic impulse signals, one group of rotating machine faults could be detected and diagnosed. However, in real wind turbine operations, impulsive fault signals are usually relatively weak to the background noise and vibration signals generated from other healthy components, such as shaft, blades, gears and so on. Moreover, wind turbine transmission systems work under dynamic operating conditions. This will further increase the difficulties in fault detection and diagnostics. Therefore, developing advanced signal processing methods to enhance the impulsive signals is in great needs.In this paper, an adaptive filtering technique will be applied for enhancing the fault impulse signals-to-noise ratio in wind turbine gear transmission systems. Multiple statistical features designed to quantify the impulsive signals of the processed signal are extracted for bearing fault detection. The multiple dimensional features are then transformed into one dimensional feature. A minimum error rate classifier will be designed based on the compressed feature to identify the gear transmission system with defect. Real wind turbine vibration signals will be used to demonstrate the effectiveness of the presented methodology.

  10. Application of geodetic leveling data on recent fault activity in Central Alborz, Iran

    Science.gov (United States)

    Saberi, Ehsan; Yassaghi, Ali; Djamour, Yahya

    2017-11-01

    In this paper, geodetic leveling data in three lines across the Central Alborz range have been utilized to analyse recent activities of the range major faults. These data gathered by National Cartographic Center of Iran in three times during the past 22-32 yr. Mathematical modeling is applied to remove systematic errors from the raw leveling data. The vertical movement (uplift or subsidence) rate is estimated from height differences of benchmarks during geodetic leveling data times. The results show that the average uplift in Central Alborz during data times varies from 17.0 ± 0.9 to 18.1 ± 0.9 mm in the hangingwall of the major North Tehran and Mosha faults, respectively. The lower values of the uplift across the faults are taken as an account for the faults locking during the data times and their possible seismic potential. Evaluation of the uplift rate for the major faults under study in Central Alborz indicates the reduction of vertical uplift from west to east along the main proven faults like the Mosha Fault. The rate of uplift in the hangingwall of the Mosha Fault decreases from 0.921 ± 0.283 (mm yr-1) (20.3 ± 0.905 mm 22 yr-1) in west to the rate of 0.508 ± 0.228 (mm yr-1) (11.7 ± 1.031 (mm 23 yr-1)) in east. The unusual subsidence anomalous in some benchmarks is considered as the effect of geological features such as Karst phenomena. Moreover, comparison on the rate of vertical movement across the Central Alborz shows the greater uplift in the southern flank (10.4 ± 0.9 mm) with respect to its northern flank (6.3 ± 0.9 mm) during the data times. This interpretation is in agreement with Global Positioning System studies that indicates a progress of young deformation in Central Alborz toward the range southern hillside.

  11. Effect of Injection Site on Fault Activation and Seismicity during Hydraulic Fracturing

    Directory of Open Access Journals (Sweden)

    Zhaohui Chong

    2017-10-01

    Full Text Available Hydraulic fracturing is a key technology to stimulate oil and gas wells to increase production in shale reservoirs with low permeability. Generally, the stimulated reservoir volume is performed based on pre-existing natural fractures (NF. Hydraulic fracturing in shale reservoirs with large natural fractures (i.e., faults often results in fault activation and seismicity. In this paper, a coupled hydro-mechanical model was employed to investigate the effects of injection site on fault activation and seismicity. A moment tensor method was used to evaluate the magnitude and affected areas of seismic events. The micro-parameters of the proposed model were calibrated through analytical solutions of the interaction between hydraulic fractures (HF and the fault. The results indicated that the slip displacement and activation range of the fault first decreased, then remained stable with the increase in the distance between the injection hole and the fault (Lif. In the scenario of the shortest Lif (Lif = 10 m, the b-value—which represents the proportion of frequency of small events in comparison with large events—reached its maximum value, and the magnitude of concentrated seismic events were in the range of −3.5 to −1.5. The frequency of seismic events containing only one crack was the lowest, and that of seismic events containing more than ten cracks was the highest. The interaction between the injection-induced stress disturbance and fault slip was gentle when Lif was longer than the critical distance (Lif = 40–50 m. The results may help optimize the fracturing treatment designs during hydraulic fracturing.

  12. Low resistivity and permeability in actively deforming shear zones on the San Andreas Fault at SAFOD

    Science.gov (United States)

    Morrow, Carolyn A.; Lockner, David A.; Hickman, Stephen H.

    2015-01-01

    The San Andreas Fault Observatory at Depth (SAFOD) scientific drillhole near Parkfield, California crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, actively deforming zones of smectite-clay gouge within a roughly 200 m-wide fault damage zone of sandstones, siltstones and mudstones. Here we report electrical resistivity and permeability measurements on core samples from all of these structural units at effective confining pressures up to 120 MPa. Electrical resistivity (~10 ohm-m) and permeability (10-21 to 10-22 m2) in the actively deforming zones were one to two orders of magnitude lower than the surrounding damage zone material, consistent with broader-scale observations from the downhole resistivity and seismic velocity logs. The higher porosity of the clay gouge, 2 to 8 times greater than that in the damage zone rocks, along with surface conduction were the principal factors contributing to the observed low resistivities. The high percentage of fine-grained clay in the deforming zones also greatly reduced permeability to values low enough to create a barrier to fluid flow across the fault. Together, resistivity and permeability data can be used to assess the hydrogeologic characteristics of the fault, key to understanding fault structure and strength. The low resistivities and strength measurements of the SAFOD core are consistent with observations of low resistivity clays that are often found in the principal slip zones of other active faults making resistivity logs a valuable tool for identifying these zones.

  13. Active Disturbance Rejection Approach for Robust Fault-Tolerant Control via Observer Assisted Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    John Cortés-Romero

    2013-01-01

    Full Text Available This work proposes an active disturbance rejection approach for the establishment of a sliding mode control strategy in fault-tolerant operations. The core of the proposed active disturbance rejection assistance is a Generalized Proportional Integral (GPI observer which is in charge of the active estimation of lumped nonlinear endogenous and exogenous disturbance inputs related to the creation of local sliding regimes with limited control authority. Possibilities are explored for the GPI observer assisted sliding mode control in fault-tolerant schemes. Convincing improvements are presented with respect to classical sliding mode control strategies. As a collateral advantage, the observer-based control architecture offers the possibility of chattering reduction given that a significant part of the control signal is of the continuous type. The case study considers a classical DC motor control affected by actuator faults, parametric failures, and perturbations. Experimental results and comparisons with other established sliding mode controller design methodologies, which validate the proposed approach, are provided.

  14. Fault Detection of a Roller-Bearing System through the EMD of a Wavelet Denoised Signal

    Science.gov (United States)

    Ahn, Jong-Hyo; Kwak, Dae-Ho; Koh, Bong-Hwan

    2014-01-01

    This paper investigates fault detection of a roller bearing system using a wavelet denoising scheme and proper orthogonal value (POV) of an intrinsic mode function (IMF) covariance matrix. The IMF of the bearing vibration signal is obtained through empirical mode decomposition (EMD). The signal screening process in the wavelet domain eliminates noise-corrupted portions that may lead to inaccurate prognosis of bearing conditions. We segmented the denoised bearing signal into several intervals, and decomposed each of them into IMFs. The first IMF of each segment is collected to become a covariance matrix for calculating the POV. We show that covariance matrices from healthy and damaged bearings exhibit different POV profiles, which can be a damage-sensitive feature. We also illustrate the conventional approach of feature extraction, of observing the kurtosis value of the measured signal, to compare the functionality of the proposed technique. The study demonstrates the feasibility of wavelet-based de-noising, and shows through laboratory experiments that tracking the proper orthogonal values of the covariance matrix of the IMF can be an effective and reliable measure for monitoring bearing fault. PMID:25196008

  15. Detection and localization of building insulation faults using optical-fiber DTS system

    Science.gov (United States)

    Papes, Martin; Liner, Andrej; Koudelka, Petr; Siska, Petr; Cubik, Jakub; Kepak, Stanislav; Jaros, Jakub; Vasinek, Vladimir

    2013-05-01

    Nowadays the trends in the construction industry are changing at an incredible speed. The new technologies are still emerging on the market. Sphere of building insulation is not an exception as well. One of the major problems in building insulation is usually its failure, whether caused by unwanted mechanical intervention or improper installation. The localization of these faults is quite difficult, often impossible without large intervention into the construction. As a proper solution for this problem might be utilization of Optical-Fiber DTS system based on stimulated Raman scattering. Used DTS system is primary designed for continuous measurement of the temperature along the optical fiber. This system is using standard optical fiber as a sensor, which brings several advantages in its application. First, the optical fiber is relatively inexpensive, which allows to cover a quite large area for a small cost. The other main advantages of the optical fiber are electromagnetic resistance, small size, safety operation in inflammable or explosive area, easy installation, etc. This article is dealing with the detection and localization of building insulation faults using mentioned system.

  16. Soil Moisture Active Passive Mission: Fault Management Design Analyses

    Science.gov (United States)

    Meakin, Peter; Weitl, Raquel

    2013-01-01

    As a general trend, the complexities of modern spacecraft are increasing to include more ambitious mission goals with tighter timing requirements and on-board autonomy. As a byproduct, the protective features that monitor the performance of these systems have also increased in scope and complexity. Given cost and schedule pressures, there is an increasing emphasis on understanding the behavior of the system at design time. Formal test-driven verification and validation (V&V) is rarely able to test the significant combinatorics of states, and often finds problems late in the development cycle forcing design changes that can be costly. This paper describes the approach the SMAP Fault Protection team has taken to address some of the above-mentioned issues.

  17. Plume Activity and Tidal Deformation on Enceladus Influenced by Faults and Variable Ice Shell Thickness

    Science.gov (United States)

    Běhounková, Marie; Souček, Ondřej; Hron, Jaroslav; Čadek, Ondřej

    2017-09-01

    We investigated the effect of variations in ice shell thickness and of the tiger stripe fractures crossing Enceladus' south polar terrain on the moon's tidal deformation by performing finite element calculations in three-dimensional geometry. The combination of thinning in the polar region and the presence of faults has a synergistic effect that leads to an increase of both the displacement and stress in the south polar terrain by an order of magnitude compared to that of the traditional model with a uniform shell thickness and without faults. Assuming a simplified conductive heat transfer and neglecting the heat sources below the ice shell, we computed the global heat budget of the ice shell. For the inelastic properties of the shell described by a Maxwell viscoelastic model, we show that unrealistically low average viscosity of the order of 10^{13} Pa s is necessary for preserving the volume of the ocean, suggesting the important role of the heat sources in the deep interior. Similarly, low viscosity is required to predict the observed delay of the plume activity, which hints at other delaying mechanisms than just the viscoelasticity of the ice shell. The presence of faults results in large spatial and temporal heterogeneity of geysering activity compared to the traditional models without faults. Our model contributes to understanding the physical mechanisms that control the fault activity, and it provides potentially useful information for future missions that will sample the plume for evidence of life.

  18. Fault detection and isolation of high temperature proton exchange membrane fuel cell stack under the influence of degradation

    Science.gov (United States)

    Jeppesen, Christian; Araya, Samuel Simon; Sahlin, Simon Lennart; Thomas, Sobi; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2017-08-01

    This study proposes a data-drive impedance-based methodology for fault detection and isolation of low and high cathode stoichiometry, high CO concentration in the anode gas, high methanol vapour concentrations in the anode gas and low anode stoichiometry, for high temperature PEM fuel cells. The fault detection and isolation algorithm is based on an artificial neural network classifier, which uses three extracted features as input. Two of the proposed features are based on angles in the impedance spectrum, and are therefore relative to specific points, and shown to be independent of degradation, contrary to other available feature extraction methods in the literature. The experimental data is based on a 35 day experiment, where 2010 unique electrochemical impedance spectroscopy measurements were recorded. The test of the algorithm resulted in a good detectability of the faults, except for high methanol vapour concentration in the anode gas fault, which was found to be difficult to distinguish from a normal operational data. The achieved accuracy for faults related to CO pollution, anode- and cathode stoichiometry is 100% success rate. Overall global accuracy on the test data is 94.6%.

  19. Fault detection and diagnosis for non-Gaussian stochastic distribution systems with time delays via RBF neural networks.

    Science.gov (United States)

    Yi, Qu; Zhan-ming, Li; Er-chao, Li

    2012-11-01

    A new fault detection and diagnosis (FDD) problem via the output probability density functions (PDFs) for non-gausian stochastic distribution systems (SDSs) is investigated. The PDFs can be approximated by radial basis functions (RBFs) neural networks. Different from conventional FDD problems, the measured information for FDD is the output stochastic distributions and the stochastic variables involved are not confined to Gaussian ones. A (RBFs) neural network technique is proposed so that the output PDFs can be formulated in terms of the dynamic weighings of the RBFs neural network. In this work, a nonlinear adaptive observer-based fault detection and diagnosis algorithm is presented by introducing the tuning parameter so that the residual is as sensitive as possible to the fault. Stability and Convergency analysis is performed in fault detection and fault diagnosis analysis for the error dynamic system. At last, an illustrated example is given to demonstrate the efficiency of the proposed algorithm, and satisfactory results have been obtained. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Geodetic Network Design and Optimization on the Active Tuzla Fault (Izmir, Turkey for Disaster Management

    Directory of Open Access Journals (Sweden)

    Haluk Ozener

    2008-08-01

    Full Text Available Both seismological and geodynamic research emphasize that the Aegean Region, which comprises the Hellenic Arc, the Greek mainland and Western Turkey is the most seismically active region in Western Eurasia. The convergence of the Eurasian and African lithospheric plates forces a westward motion on the Anatolian plate relative to the Eurasian one. Western Anatolia is a valuable laboratory for Earth Science research because of its complex geological structure. Izmir is a large city in Turkey with a population of about 2.5 million that is at great risk from big earthquakes. Unfortunately, previous geodynamics studies performed in this region are insufficient or cover large areas instead of specific faults. The Tuzla Fault, which is aligned trending NE–SW between the town of Menderes and Cape Doganbey, is an important fault in terms of seismic activity and its proximity to the city of Izmir. This study aims to perform a large scale investigation focusing on the Tuzla Fault and its vicinity for better understanding of the region's tectonics. In order to investigate the crustal deformation along the Tuzla Fault and Izmir Bay, a geodetic network has been designed and optimizations were performed. This paper suggests a schedule for a crustal deformation monitoring study which includes research on the tectonics of the region, network design and optimization strategies, theory and practice of processing. The study is also open for extension in terms of monitoring different types of fault characteristics. A one-dimensional fault model with two parameters – standard strike-slip model of dislocation theory in an elastic half-space – is formulated in order to determine which sites are suitable for the campaign based geodetic GPS measurements. Geodetic results can be used as a background data for disaster management systems.