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Each autonomous technological process requires an early fault detection system as an integral part of its infrastructure. Complex fault diagnostics system must be able not only to quickly detect any unwanted deviation from nominal function, but also to make a competent estimate of the type and source of possible failure. The article presents the fault diagnostics system based on Markov model. It uses...
As the core component of rotating machinery, rotor system is often subjected to the different torque load in the operation process, resulting in the change of bearing load, system vibration and friction behavior between axis and bearing. Further, the operation situation of rotor system is changed. At present, the perfect conclusion has not been formed to identify torque load of rotor system. In this...
Technology advances provide a myriad of advantages for VLSI systems, but also increase the sensitivity of the combinational logic to different fault profiles. Shorter and shorter faults which up to date had been filtered, named as fugacious faults, require new attention as they are considered a feasible sign of warning prior to potential failures. Despite their increasing impact on modern VLSI systems,...
Induction generators used in windmills usually work in non-stationary conditions, due to the varying speed of the wind. Therefore, in order to perform its diagnosis through the stator current analysis, adequate time-frequency transforms must be used. Discrete Wavelet Transform succeeds detecting the highest amplitude sideband harmonic caused by asymmetries. Nevertheless, it fails with the rest of...
In comparison to rotor bar fault detection for mains fed induction machines the detection in inverter-fed drives is especially challenging. The most important reasons are the disturbances introduced by the fast switching of the inverter. Moreover the fault indicator is influenced also by control dynamics and load changes. In addition most known fault detection technologies need a certain load level...
In this paper we propose an on-die monitoring scheme to detect and count transient faults (TFs) resulting, as well as not resulting in output SEs, affecting the inputs of data-path latches/flip-flops. This approach allows an early monitoring of the latches/flip-flops vulnerability to TFs, thus discovering intrinsic weaknesses of design or process. The proposed monitoring scheme features a very low...
In this work, a new method for PQ analysis is proposed based on the use of neural processing aiming to decouple the information from different disturbances from the power system signal. The system was implemented and tested using a simulated database showing the good performance of the proposed technique for signal separation. It was shown that the proposed method could also be used as a preprocessing...
This paper presents the application of S-transform and rule based system for diagnosing power quality problems which are related to voltage disturbances. Such voltage disturbances can be caused by permanent or non permanent faults. A permanent fault causes permanent damage and power interruption to the customers whereas a non permanent fault can be categorized as either transient or incipient faults...
Proper interpretation of fault and disturbance data is critical for the reliability and continuous operation of the power system. A correct interpretation gives you valuable insight into the conditions and performance of various power system protective equipment. Analyzing records is not an intuitive process and requires system protection knowledge and experience. Having an understanding of the fundamental...
Harmonic analysis of motor current has been used to track the speed of motors for sensorless control. Algorithms exist that track the speed of a motor given a dedicated stator current measurement, for example. Harmonic analysis has also been applied for diagnostic detection of electro-mechanical faults such as damaged bearings and rotor eccentricity. This paper demonstrates the utility of harmonic...
Fault monitoring is one of the main activities of fault tolerant distributed systems. It is required to determine the suspected/crashed component and proactively take the recovery steps to keep the system alive. The main objective of the fault monitoring activity is to quickly and correctly identify the faults. A fault monitoring system which is quick to declare faults increases the chances of false...
This paper describes a field-tested technique that uses aggregate current measurements to detect faults in multiple induction machines. This new approach reduces costs and potentially increases reliability. The paper begins with a description of the field-tested system. It then describes three analytical techniques that have been applied to aggregate data in order to identify faults. The paper uses...
Aeroengine components performances deteriorate due to wearing, foreign object ingestion damage or other factors. The engine monitoring and fault diagnostics systems are developed to trace the components health condition and to help make the maintenance decision in order to avoid severe damages. Based on transient gas path measurements, the engine monitoring and diagnostics are carried out through...
Conventional electric distribution systems are radial in nature, and are supplied through a main source. These networks have a very simple protection system which is usually implemented using fuses, re-closers, and over-current relays. Recently, great attention has been paid to applying distributed generation (DG) throughout electric distribution systems. Presence of such generation units in a network,...
This paper proposes a novel method based on multiple adaptive neuro-fuzzy in combination of statistic method to detect and diagnose the faults occurring in complex dynamical systems. The basic idea is to use PCA to extract the features for reducing the complexity of the data achieved from a process. The most superior features are fed into multiple ANFIS to identify different faulty conditions in order...
This paper presents principles and results of dynamic testing of an SRAM-based FPGA using time- resolved fault injection with a pulsed laser. The synchronization setup and experimental procedure are detailed. Fault injection results obtained with a DES crypto-core application implemented on a Xilinx Virtex II are discussed.
Present and future semiconductor technologies are characterized by increasing parameters variations as well as an increasing susceptibility to external disturbances. Transient errors during system operation are no longer restricted to memories but also affect random logic, and a robust design becomes mandatory to ensure a reliable system operation. Self-checking circuits rely on redundancy to detect...
Error correction is an effective way to mitigate fault attacks in cryptographic hardware. It is also an effective solution to soft errors in deep sub-micron technologies. To this end, we present a systematic method for designing single error correcting (SEC) and double error detecting (DED) finite field (Galoisfield) multipliers over GF(2m). The detection and correction are done on-line. We use multiple...
In this paper we present a low cost fault-tolerant attitude determination system to a scientific satellite using COTS devices. We related our experience in developing the attitude determination system, where we combine proven fault tolerance techniques to protect the whole system composed only by COTS from the effects produced by transient faults. We detailed the failure cases and the detection, reconfiguration...
The objective of this paper is to introduce Newland Harmonic wavelets and Pincus (1991) approximate entropy are applied to extract weak cycle jumps. Because some weak vibration signals contained strong noises are very important for fault forecast. Based on harmonic wavelet mesh plot of the vibration signals, we can induce contours of the mesh map with log space, then, we offer the time-frequency profile...
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