the paper analyzes the power-grid connection for a large and medium photovoltaic (PV) plant in details, and it creates a mathematic model for PV inverter and a parameter model for power distribution. The paper also do...
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the paper analyzes the power-grid connection for a large and medium photovoltaic (PV) plant in details, and it creates a mathematic model for PV inverter and a parameter model for power distribution. The paper also does some research on the grid-connected character between large PV generation system and weak grid, and it focuses on output voltage and current harmonic while connected. Depending on the simulation result and real operating data of three-phase PV inverter, which founded on the traditional controlling algorithm, the paper proposes a brand new way. The method bases on the space-vector theory, and it can validly decrease the PV grid-connected output voltage and current harmonic, and improve the reliability. The theoretical analysis and partial operation results have proved the correctness of grid-connected features;also, it will provide the theory and grid-connected instruction for Chinese new energy strategy as well as the world.
ABSTRACT: Techniques were developed using vector and raster data in a geographic information system (GIS) to define the spatial variability of watershed characteristics in the north‐central Sierra Nevada of Californi...
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This paper uses multi-conductor transmission line (MTL) to model transformer windings. According to the symmetry of windings, a 2D equivalent finite element model can be set up under ANSYS environment. On the basis, F...
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This paper uses multi-conductor transmission line (MTL) to model transformer windings. According to the symmetry of windings, a 2D equivalent finite element model can be set up under ANSYS environment. On the basis, Finite Element Method (FEM) is used to calculate the distributed parameters in transformer windings. In the process of calculation, the skin effect is focused on. The frequency-dependent parameters are calculated at the different frequency points based on FEM. Therefore, the calculating parameters are helpful to research on propagation characteristics of PD pulses in electric equipments.
Power line, where more than two distributed parameters (resistance and reactance) are taken into account, is considered as two-port network. Formulas, giving an unambiguous relationship between electrical quantities a...
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ISBN:
(纸本)9781728139432
Power line, where more than two distributed parameters (resistance and reactance) are taken into account, is considered as two-port network. Formulas, giving an unambiguous relationship between electrical quantities at the ports of a two-port network, do not detailed show the influence of three or four parameters (in addition, conductance and capacitive susceptance) on line electrical quantities. The influence of distributed parameters occurs through the sine and hyperbolic sine of the components of propagation factor. How distributed parameters should be changed it depends on what properties of the line it is desirable to get. More adverse of distributed parameters is specific susceptance both in single and parallel lines.
Human skin color detection plays an important role in the applications of skin segmentation, face recognition, and tracking. To build a robust human skin color classifier is an essential step. This paper presents a cl...
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Human skin color detection plays an important role in the applications of skin segmentation, face recognition, and tracking. To build a robust human skin color classifier is an essential step. This paper presents a classifier based on beta mixture models (BMM), which uses the pixel values in RGB space as the features. We propose a Bayesian estimation method based on the variational inference framework to approximate the posterior distribution of the parameters in the BMM and take the posterior mean as a point estimate of the parameters. The well-known Compaq image database is used to evaluate the performance of our BMM based classifier. Compared to some other skin color detection methods, our BMM based classifier shows a better recognition performance.
Many inputs for simulation optimization models are assumed to come from known distributions. When such distributions are obtained from small sample sizes, the parameters of these distributions may be associated with a...
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ISBN:
(纸本)9781479920778
Many inputs for simulation optimization models are assumed to come from known distributions. When such distributions are obtained from small sample sizes, the parameters of these distributions may be associated with an "uncertainty set" or ranges. The presence of this uncertainty means that one or more solutions may be optimal depending on which parameters from the set are used. In this paper, we present a graphical methodology that combines bootstrap sampling and cross-evaluation techniques to visualize the data driven support for alternative solutions for problems in which distribution parameters are estimated using small sample sizes. We illustrate the methodology using a voting machine allocation problem.
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