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This paper is concerned with the management of the large amount of information of large-scale PV systems, a new approach that can monitor the status and detect faults for large-scale PV systems is derived. We first design a new type of photovoltaic (PV) arrays connection, and establish its framework for fault diagnosis. Then , based on the so called "data fusion" technique, we merge the...
Voltage sag has became the most concerned about power quality problems. Voltage sag source detection for power quality fault detection, diagnosis and to ease the formulation of strategy is necessary. This paper proposes a new method about voltage sag disturbance source location based on real current component. The product of the RMS current and the power factor angle at the monitoring point is employed...
A method based on the D-S (Dempster-Shafer) evidential theory is presented and applied to diagnose the broken rotor bars of induction motors. Wavelet packets decomposition of the three-phase stator current is performed based on the frequency partition characteristics of the wavelet packets transformation; The faults characteristic vector (evidence) of the broken rotor bars is established by the RMS...
Through the analysis of the electromagnetic properties for the rotor coil of turbine generator, we obtained the main magnetic field variation characteristics for the rotor winding and put forward the short circuit fault between rotor inter-turns causing the potential difference and circulation between the parallel branches of generation stator winding spectral method was applied on the spectrum analysis...
This paper has summarized the history of the development of the state monitoring system of the power transformer and introduced the present situation in research, especially the multifold comparison on different methods to diagnose the trouble in transformer. This paper not only takes the comprehensive analysis on the extant online monitoring equipments, which is based on DGA, and methods of trouble...
Vibration faults frequently occurring to the feed water pump in large-scale power plants are diagnosed by the integrated neural network based on MATLAB. The integrated neural network for fault diagnosis is established from individual neural network and on the basis of information fusion. The strategies and principles for the realization and formation of integrated neural network are analyzed and a...
Bayesian Networks is used to study and deal with the reasoning under uncertainty in the power system fault process. Data mining method can find useful information for decision-making from massive history data. Therefore, an Augmented Naive Bayesian power network fault diagnosis method based on data mining is proposed to diagnose faults in power network. The status information of protections and circuit...
Based on the dissolved gases analysis and grey relational theory, a fault diagnosis method for transformers is proposed. Fault diagnosis in transformers has several parameters such as the severity of fault and the kind of fault, a lot of typical fault samples are divided into several sets according to the fault type. The practical data are analyzed using grey relational analysis. The experiment showed...
Any failures in these equipments directly reduce network reliability and increase maintenance costs. Consequently, the preventive maintenance techniques are increasingly developed. In this regard, frequency response analysis is an appropriate method in order to diagnose any change which occurs in transformer physical construction. This contribution has been concentrated on fault diagnosis by use of...
As power system interconnections become more prevalent, there has been an increase in use of thyristor controlled shunt connected compensation devices for dynamic power compensation and enhancement of real power transmission capacity. In this paper, an enhancement technique of real power transfer capacity of transmission lines is presented. A static var compensator (SVC) is designed and applied to...
Exploring a new method of line-tracking is the key to smart grid construction. Obtaining information of high-voltage transmission system by helicopter or unmanned aerial vehicles (UAV) will bring numerous images. The research of extra matter recognition of transmission system based on Hough Transform (HT) is performed in this paper. The gradient of gray image is used to detect the edge of transmission...
In the variable frequency driver system of induction motor, the DC-side current of converters and the AC-side current of rectifiers are analytically analyzed using switching functions of converters and rectifiers when induction motors would be in fault state. The transmission rules of faults characteristic information in driver system were derived, and the fault features frequency components corresponding...
A new fault isolation and restoration technique for distribution automation, which employs local Ethernet network, is presented. It can isolate all short circuit faults in the loop within 300ms and restore the supply of healthy sections in less than 1.2 seconds. A reliable fault location method for isolating the single phase to ground fault in the non-effectively earthed network, which makes use of...
The mathematical model of the gas turbine performance in the condition of fault is established by using the exergy efficiency, which as a figure of merit of the work potential that based on the second law of thermodynamics. The performance matrix of fault model is derived by using the small deviation method. The exergy efficiency is contrasted with the efficiency, which is the traditional function...
It is opinion that climate change on the planet is largely dependent on the increase of greenhouse gases in the atmosphere and that this effect is related largely to human activities that make CO2. Reducing the discharge of CO2 has therefore become a common objective of the international community, including China. There are various actions that are proposed for the reduction of the gas: increased...
Present single-phase reclosure in ultra-high-voltage (UHV) and extra-high-voltage (EHV) transmission lines normally using a dead reclosing time may aggravate severe damage to the system and equipments, for unsuccessful reclosure in permanent fault or insufficient transient fault. Thus, it is important to study on the single-phase permanent detection technique aiming to lower unsuccessful reclosing...
As the fault of key components for shield machine caused great economic loss and harmful social effect, An on-line condition monitoring and fault diagnosis system was designed for large-scale engineering machine(shield machine). At first the paper described the object to build remote monitoring center, and then introduced in detail monitoring equipment by machine loaded which consisted of four parts,...
The mass imbalance often cause the vibration of high-speed rotation machinery in actual use. And it's the most common cause of the malfunction. Based on the theory of rotor dynamics, we can diagnose the failure and its causes more accurately by applying the software to doing simulation analysis of characteristics of rotor dynamic. Moreover, it provides reliable basis for the further solutions to the...
This paper uses the grid-connected photovoltaic (PV) power plant electromechanical transient simulation model on FASTEST (Fast Analysis of Stability using the Extended equal area criterion and Simulation Technologies) to do the simulation of PV power plant integrated to the grid. The simulation includes the largest installed capacity of PV power plant and the response of PV power plant when solar...
This paper analyses the advantages and disadvantages of fault line detection methods for neutral un-effectual grounded system at home and abroad, proposes a novel fault line detection algorithm based on morphological operator and rough set theory. Using rough set theory to amplify weak signal and morphological operator to identify the polarity of the fault zero sequence current's first wave, it can...
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