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There has not been an effective simulation and analysis method for the prediction of the reliability of monitoring system for a long time. This paper uses the cloud model theory and fault tree analysis (FTA) to transform elements that affect the reliability of the monitoring system, such as temperature, humidity, voltage, and stress of parts, into environmental factors, in order to obtain a new method...
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...
It's important for us to carry on reliability research of protection system. There are three methods to analyze and compute reliability index of electric relay protection system: Markov method, Fault Tree Analysis (FTA), Event Tree Analysis (ETA). The paper describes how to use these three methods to carry out quantitative analysis of protection system reliability and discusses feature and difference...
Solid power system planning is fundamental to the safety, reliability and economy of power system operation. In the deregulated power grid environments, power grid planners not only have to handle massive geographic data, power equipment parameter data and grid operational data, but also have to solve very complex decision-making problems when they are committing power grid planning. Thus, it is necessary...
In this paper, the comparison within documents were introduced, including MP, China C&I, FSC Principle and Zhejiang Provincial C&I. Then a modeling structure for sustainable forest management criteria for a unit level was conducted. This was a case study in Kaihua state owned forest farm in south China. Considering the situation of the farm a questionnaire form was given followed the CIFOR...
A novel field modulated magnetic gear (FMMG) with concentric configuration is proposed and introduced to the drive train for a wind turbine system, which eliminates the vibration, noise and lubrication problems of mechanical gearbox and avoids the size and weight issues of directly-driven wind turbines The efficiency and reliability are improved simultaneously. Based on the static field computations...
The key of sustainable development of newly urbanized areas often lies in tackling with issues, such as population growth, growing resources constraints, coordination between regional and urban needs, etc. Water, as one of the shared and liquid resources, has been playing a more and more important role in sustainable urban planning nowadays. Conventional water resource planning concept alone, i.e...
A method of reliability evaluation for complex medium-voltage distribution system based on feeder partition model and the minimal path method is proposed in this paper. According to the topology of distribution system, a distribution network is divided into different zones, and then the distribution network is changed into an oriented diagram. Applying the minimal path method, this diagram is divided...
There are two primary troubles having effect on reliability in tradition traveling-wave distance protection schemes. One is reflection wave identification for single-ended traveling-wave protection (A-type), and another is time synchronization for two-ended traveling-wave protection (D type). This paper proposes a novel protection for transmission line unsymmetrical grounded faults, which only needs...
From the perspective of optimal LCC(Life cycle cost), this paper studied the method to develop a reasonable maintenance strategy of power equipment. The deterioration theory in the field of mechanical engineering was led in, based on that we analyzed the failure rates of each repair period and established the model of the optimal problem, then, through a case study, we got the optimal maintenance...
Smart substation is one of the key parts of smart grid and the network of process layer is an important foundation for smart substation which is related to the reliability and real-time of data acquisition and switch control. The type of message of process layer which include GOOSE (General Object-Oriented Substation Event), MSV (Multiple Sample Value) and synchronization with network are generalized...
Optimal switching device placement is of vital importance for distribution networks' planning and operation. The combination of distributed generation (DG) and main networks is considered a principle way that could reduce investment outlay, lower the energy depletion and improve reliability of distribution systems. At present, all the study on DG impact on reliability of distribution systems is negative...
Firstly the paper introduces the characteristics of Electrical Fast Transient (EFT) and analyzes some maloperation cases of the current differential protection for transformer. Based on the characteristic of electrical fast transient burst, an anti-interference criterion is presented. Analysis of field record data and a large number of simulation show that the presented criterion can effectively improve...
The power loss and voltage distribution of distribution network are closely related to the site and size of DG and the load distribution. A new method of DG optimal placement is proposed based on load centroid. The district DG supplied is thought as an irregular shape load block and the load size is thought as quality. The power loss is the least when the DG is installed at the load centroid. The...
This paper presents an improved current differential protective principle. Marti model of the transmission line is applied in this principle, which place emphasis on solving frequency-dependent line parameters. The operating current expressions for an internal fault are also deduced in frequency domain. Finally, simulating comparison have been carried out between the proposed protective principle...
This study examines a new concept called network competence. Based on the investigation of network competence dimensions, 219 questionnaires distributed to new ventures in Chinese regions, and a comparison research conducted by using single step dimension, two-step four dimensions and three-step four dimensions measurement model. As the result shown, network competence can be conceptualized as composed...
Global weather condition is deteriorating, and the impacts on the transmission and distribution system are more and more serious. Therefore it is especially important to take the reliability impact assessment of the grid considering the weather factors. This article will divide the weather state into normal weather, bad weather and catastrophic weather, and establish the power system reliability evaluation...
With the development of High Voltage Directed Current (HVDC) transmission technology, the increasing numbers of HVDC projects and the appearance of HVAC/HVDC composite systems, the reliability of HVDC system has become a very important factor to the bulk power system. This paper provides the reliability evaluation model of the composite power systems with DC transmission lines, which includes the...
A reliability predication method based on GO methodology for fuel cycling system (FCS) in pebble bed reactor is introduced. Regarding to the specific structure and function of the FCS, the probability of FCS was defined. By using decomposition and reconstruction the probability of complex bridging system was calculated directly, some new operators and corresponding algorithm were derived. The comparison...
The principle of how to arrange reserve services in CSG and UCTE are surveyed. Several issues in reserve services of CSG are pointed out. A new reserve system is proposed, which include Primary Frequency Control Reserve (PFCR), Emergency Reserve (ER), and Long-term Reserve (LR). The function, arrange principle, statistical method for real-time monitoring of each kind of reserve are expatiated. A vision...
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