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This paper designs a fault diagnosis model for circuit breaker based on power dispatching system. The model has three levels including data level, criterion level and judging level. The data level consists of data obtaining, data handling and fault database. The criterion level consists of operating time characteristics model, fault tree and repository. The judging level is logical judging method...
The three-phase induction motor is one of the most employed equipment in industrial premisses. Despite of its reliability and robustness, these machines can present faults due to the operation time, harsh operating conditions, voltage unbalance, among other factors. In this work, a methodology for intelligent diagnose of multiple faults in induction motors by using a discretization of currents and...
Fault diagnosis constitutes a problem in electric power systems with relevant economic impact for operators and stakeholders. Artificial neural networks have been proposed in the literature to deal with this problem in a significant number of applications. However, most proposals are based in ad-hoc structure specification and model regularization, which compromises the direct application of the algorithms...
Electrical signature analysis (ESA) has been increasingly used in condition-based maintenance programs of synchronous generators. The fault diagnosis is based on the analysis of failure patterns in the current or voltage signatures, which allow to distinguish possible incipient faults in the machine. The failure patterns are usually dependent on the line frequency, rotor rotation frequency and some...
This paper deals with the diagnosability analysis of intermittent faults in discrete-event systems using a diagnoser-based approach. Intermittent faults are defined as faults that can automatically recover once they occur. Firstly, we discuss the modeling of intermittent faults in finite state automata and revisit two existing diagnosability properties regarding the detection of fault/recovery occurrences...
State Grid of China plans to put a ± 500kV/3000MW four-terminal voltage source converter based high voltage direct current (VSC-HVDC) transmission system into operation by 2020. In compare to existing VSC-HVDC transmission systems, this system has higher voltage level and transmission capacity. Accordingly, grid devices and topology would be significantly different. This paper introduces configuration...
As secondary equipment in smart substation all follow IEC 61850, it makes information sharing and interoperability the biggest differences between the smart and the conventional. It makes condition-based maintenance (CBM) which relies on high performance condition monitoring system feasible. In smart substations, the condition of protection and control equipment, network and communication links can...
A continuous real-time data acquisition and communication equipment based on Advanced RISC Machine and Field Programmable Gate Array is designed and developed, on the basis of which an on-line monitoring and fault diagnosis system for high voltage circuit breaker is realized. Mechanical, electrical and environmental parameters of the switching process can be gathered by this system. The function modules...
Condition based maintenance (CBM) is considered to be the most effective maintenance strategy in a performance contract. It significantly increases the system availability and efficiency, meanwhile reduces service affecting faults and maintenance cost, especially when combined with online monitoring of real-time condition data of assets. For the above reasons, CBM has been paid more attention in railway...
A systematic method is proposed to approach complete fault coverage for catastrophic faults in analog circuits. In the proposed method, a fault propagation graph is first created from the circuit netlist. Standard graph theory techniques are then employed to identify a minimal set of observation points (MOP) such that, by monitoring these points, complete fault coverage can be achieved, i.e., all...
Test-per-clock BIST scheme has the advantages of very short test application time and small test data volume. However, conventionally this scheme needs an extra parallel response monitor for response analysis that may lead to large area overhead. This paper presents a new test-per-clock BIST method that can perform both pattern generation and response compression concurrently in the same LFSR-based...
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,...
This paper presents an engineering design of a real-time fault monitoring method for power-on-wheel electric vehicles, which have four independent wheel units. Each independent unit has an in-wheel motor with its own steering control system. A central control unit is used to coordinate the four wheels and translate the driver's idea onto the wheels, as such there is no mechanical link between these...
This paper presents an intelligent detection algorithm based on BP Neural Network, which is based on the current curve change rule of the turnout switch machine. Firstly it analyzes characteristics of each stage of turnouts device operating current curve, summarizes the typical turnout fault operating current curve; Then, establishes the mapping data sets between the action current and turnout fault...
This paper presents model based approach for diagnosis of open circuit power switch faults in full bridge DC-DC converter of a photovoltaic system. The control circuitry of the proposed converter monitors and regulates output current, whenever output current lowers, controller monitors current at test points and localizes faulty switch by comparing fault features. This minimizes efforts required for...
This paper investigates the use of fibre Bragg grating (FBG) accelerometers for wide band vibration monitoring in wound rotor induction generators. The sensor performance is assessed in a series of experiments on a laboratory test rig comprising a 30kW induction machine operating in healthy conditions and with electrical or mechanical fault. Vibration measurements are processed and analyzed in the...
The intelligent decision-making of Centralized Control Center of Substation (CCCOS) for accident treatment contributes to the self-healing and reliable supply of power system, for which deals with the operation and maintenance of the gird directly. In this background, a novel accident treatment and decision system based on CCCOS is proposed in this paper. At first, the differences in the accident...
The biogas generator system put into practice has the deficiencies of poor stability, robustness and real-time, which has impacted the promotion and development of biogas power generation technology greatly. This paper designed a new monitoring model according to these deficiencies. This model established fault diagnosis subsystems according to the procedure of gas power generation, based on probability...
Obtaining fault coverage information for functional input sequences is often very difficult. Although many simulation-based techniques have been proposed, they are generally computationally expensive, and if the input sequence changes, new expensive simulations must be run. In this paper, we propose a new type of hardware monitor for the probabilistic determination of how many times a fault was likely...
This paper studies the method of fault diagnosis in HVCB (high voltage circuit breaker), and discusses application of D-S (Dempster-Shafer) evidence theory in the HVCB's faults. D-S evidence theory is discussed the problem of the validity, and out of work in the cases, a theory of evidence and the improved method were provided to resolve the D-S algorithm in realizing the conflict problem of the evidence...
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