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11th International Conference on Electrical Machines and Systems

作者： Zhao, Chun Ruan, Jiangjun Du, Zhiye Liu, Shoubao Yu, Yefeng Zhang, Yuanhang Wuhan Univ Inst Adv Technol Elect Engn Wuhan 430072 Peoples R China

ISBN: (纸本)9787506292214

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 an propagation characteristics of PD pulses in electric equipments.

关键词： multi-conductor transmission line transformer winding finite element method distributed parameter skin effect

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Complex Domain Analysis Method Based on EM Waving for Transmission Line Transient Faults

Complex Domain Analysis Method Based on EM Waving for Transm...

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Asia-Pacific Power and Energy Engineering Conference (APPEEC)

作者： Pan Chao Wang Zezhong Dong Bo Zheng Qing North China Elect Power Univ Sch Elect & Elect Engn Beijing Peoples R China

ISBN: (纸本)9781424462551

A concept named 'steady process in transient condition' is proposed for transmission line based on the transient expression of electromagnetic traveling wave. Considering the impact of distributed parameters and the characteristics of electro-magnetic wave, the transmission line model is built. Wave impedance factor is defined with line voltage fluctuation. The voltage equation is derived and the former is researched for complex domain projection, which is the improvement of orthogonal projection. And the voltage is approached exactly. The fault location function has been built up which can be used to confirm the fault position with effective measurement of voltage. The impedance factor is studied on variety, and the location result is more closely approximated to real situation. Without convolution, the efficiency and accuracy of this method has been proved. And the edge effect caused by orthogonal scaling function is solved. Complex domain analysis cannot be affected by step, and the adaptive calculation for the sampling frequency through simulation and analysis.

关键词： electro-magnetic waving distributed parameter complex domain projection orthogonal scaling

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Long Transmission Lines Fault Location Based on parameter Identification Using One-Terminal Data

Long Transmission Lines Fault Location Based on Parameter Id...

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Asia-Pacific Power and Energy Engineering Conference (APPEEC)

作者： Wang, Bin Suonan, Jiale Liu, Heqing Song, Guobing Xi An Jiao Tong Univ Dept Elect Engn Xian 710049 Shaanxi Peoples R China

ISBN: (纸本)9781457705472;9781457705465

In this paper, an accurate fault location algorithm based on parameter identification using single-ended data is presented. It is inferred from the differential equations of fault state network and fault component network based on the R-L transmission lines model. And it takes the resistance and inductance of the system behind the fault point, the fault distance and fault resistance as unknown variables. These four unknown variables can be expressed by the coefficients of fault location equations and, therefore, can be obtained by solving those coefficients. When it comes to the distributed parameter transmission lines, an improved algorithm, combining filtering and compensating, is carried out to reduce the model error. Theoretical analysis and simulation results prove that this algorithm is of high accuracy and low time-consumption. Besides, it doesn't need iteration and the solution is unique.

关键词： long lines fault location parameter identification distributed parameter compensation algorithm

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Numerical Analysis of Retrial Queueing Systems with Conflict of Customers and an Unreliable Server

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Journal of Mathematical Sciences (United States) 2019年第5期237卷 673-683页

作者： Kuki, A. Bérczes, T. Sztrik, J. Kvach, A. University of Debrecen Debrecen Hungary Tomsk State University Tomsk Russian Federation

In this paper a closed retrial queueing system is considered with a finite number of customers. If an arriving (primary or secondary) request finds the server busy, two modes are possible: the job is transferred to the orbit (no conflict) or the job under service is interrupted and both of them are transferred to the orbit (conflict). Jobs in the orbit can retry reaching the server after a random time. The unreliable case where the server is subject to breakdown is also investigated. These types of systems can be solved by numerical, asymptotical, and simulation methods. The novelty of the investigations is that it provides a new approach to an algorithmic solution for calculating the steady-state probabilities of the system. With the help of these probabilities the main performance measures can be computed. Several sample examples illustrate the effect of different parameters on the distribution on requests in the system. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

关键词： Eye Sockets Orbits jobs Conflict (Psychology) Servers distributed parameter

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Research and realization of a lumped parameter dynamic model for fluid transmission line

Research and realization of a lumped parameter dynamic model...

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Asian Simulation Conference/5th International Conference on System Simulation and Scientific Computing

作者： Gao, QH Huang, XX Guo, XS Xian Res Inst Hi Tech Xian 710025 Peoples R China

ISBN: (纸本)7506255715

It is pointed that distributed parameter model of fluid transmission line, represented by PDEs, have to be approximated in a time domain simulation. In this paper, the transcendental transfer functions are approximated by rational transfer functions based on Krus's method, and a lumped parameter model for pressure and flow dynamics in rigid uniform transmission lines of circular cross section is given. The model is suit for ODE simulators and appears to be accurate and effective. A SIMULINK realization is given, and impulse response is computed as an example.

关键词： Transmission Lines TRANSFER FUNCTIONS TIME-DOMAIN Cross section lumped parameter distributed parameter Fluid IMPULSE RESPONSE

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Crosstalk for curvilinear conductors by utilising a nonuniform transmission line approach

Crosstalk for curvilinear conductors by utilising a nonunifo...

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10th Topical Meeting on Electrical Performance of Electronic Packaging

作者： Ye, CF Li, EP Shenn, GY Inst High Performance Comp EMC Div Singapore 116281 Singapore

A novel approach to derive nonuniform transmission line equations for curvilinear multiconductor systems by using scalar and vector potentials associated with boundary conditions is presented. Crosstalk of bent conduc... 详细信息

ISBN: (纸本)0780370244

关键词： nonuniform transmission line distributed parameter discontinuity

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Spherical Elastic-Plastic Waves

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Journal of Vibration and Control 1995年第3期1.0卷 345-360页

作者： Ziegler, Franz Irschik, Hans Holl, Helmut Civil Engineering Department Technical University Vienna Wiedner Hauptstraße 8-10/E201 Austria Institute of Technical Mechanics Johannes-Kepler-University Linz-Auhof A-4040 Austria

By examining the micro-mechanical foundation of thermoplasticity and ductile damage, an indica tion of its continuum effects, which are to be considered as material imperfections of the ideal linear elastic background structure, is given. This approach, originally developed for structural vibrations, was recently extended to include uniaxial propagating waves. This method suggests pursuing the initially elastic wave until it produces plastic deformation, which means a distortion and thus a source that emits elastic waves. Since the spherical waves in such a procedure must be derived from nondispersive D'Alembert wave functions, nonlocal sources extending from each of the plastic sources to infinity are ignited as well and contribute to the elastic wave pattern. The contribution of thermal stresses resulting from the rapid changes of temperature that are produced under adiabatic conditions by the dissipated energy are included in the general analysis, but the material parameters are kept constant. In terms of the control theory of distributed parameter time variant systems, a typical feedback mechanism is constructed. By dividing space into sufficiently small cells, the dis tortion may be kept constant during a yielding event, and by superposition of all the waves, the exact solution, including plastic wave fronts, is obtained. By means of the constitutive relations, strength and distribution of the internal sources are updated after each time step. One major aspect of the procedure is the consideration of the constitutive relations at a late stage of the solution routine. Yet all the merits of the elastic dynamic Green's function are taken into account. The nonlinear spherical wave problem resulting from an explosion in a cavity is solved for the special case of an ideal elastic plastic material under isothermal conditions and without any ductile damage to check the resulting wave pattern by comparison with previously published ones. © 1995, Sage Publications. All r

关键词： distributed parameter elastic waves feedback control nonlinear waves Plastic shock plastic source time variant system

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System dynamics and feedback control design problem formulations for real time ramp metering

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Journal of Integrated Design and Process Science 2000年第1期4卷 37-54页

作者： Kachroo, Pushkin Krishen, Kumar Bradley Department of Electrical and Computer Engineering Center for Transportation Research Virginia Polytechnic Institute and State University Blacksburg VA United States NASA Johnson Space Center Houston TX United States

This paper formulates the ramp metering control problem as a real-time feedback control problem. The development is shown by modeling freeway sections, and hence the results are immediately applicable to isolated ramp metering problems. The ideas presented in this paper can be utilized to develop coordinated ramp metering feedback control techniques. Three different forms of the formulation for are presented: (1) distributed parameter system form derived from the conservation law;(2) space discretized continuous lumped parameter form;(3) space and time discretized lumped parameter form. These formulations can be considered as the starting points for development of feedback control laws for the different control problems stated in this paper. This paper presents the feedback control problems and a new nonlinear control design for an isolated ramp metering problem. Simulations are performed for the isolated case using the new nonlinear feedback control law which show very encouraging results. © 2000, IOS Press. All rights reserved.

关键词： .inflow space and time control problems SYSTEM DYNAMICS feedback control problem distributed parameter ramp metering control isolated ramp feedback control laws

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A Novel Method to Improve the Location Accuracy of A Category of Fault Locators

A Novel Method to Improve the Location Accuracy of A Categor...

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Asia-Pacific Power and Energy Engineering Conference (APPEEC)

作者： Xin, Jianbo Lin, Xiangning Ctr Res & Dev Jiangxi Prov Elect Power Res Inst Nanchang Jiangxi Peoples R China HUST Dept Elect Engn Wuhan Peoples R China

ISBN: (纸本)9781424462551

It is very desirable to achieve high accuracy in fault location due to the increasing demands of fast detection and clearance of fault of transmission line. Most fault location algorithms incorporated in the fault recorders are based on the lumped parameter single-ended circuit model. Therefore, their accuracy is not satisfactory in many scenarios. A new revising scheme which can improve the accuracy of above type of methods is presented in this paper. The measured distance resulting from the lumped parameter circuit model is converted to the corresponding positive sequence measured impedance. Then, the relation between real distance and positive sequence measured impedance of fault circuit based on Bergeron model is be established. Thereby, the improved algorithm resulting from the relation of real distance and measured distance can be obtained. This paper presents the theory of the technique and the results of ATP simulation tests to demonstrate its performance.

关键词： Single-ended fault location distributed parameter Lumped parameter ATP simulation tests

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On the Estimation of the Exponential Distribution of parameters

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Journal of Mathematical Sciences (United States) 2016年第4期216卷 569-576页

作者： Lominashvili, G. A. Tsereteli State University Kutaisi Georgia

In the present paper, the problem of estimation of the exponential distribution of parameters is investigated. In Sec. 1, the ordinary exponential distribution is considered, and the parameter λ is estimated by means of censored observations by the pseudomaximal likelihood method. It is shown that the estimator is asymptotically consistent and effective. In Sec. 2, the problem of estimation of parameters of the truncated exponential distribution is considered using the maximal likelihood method. The existence and uniqueness of the solution corresponding to the likelihood equation are shown. The practical application of the obtained results with the aid of computer realization is given. In particular, a sample of size n = 1000 is selected, which is distributed by the truncated exponential law. The sample mean x¯ = 1.3435 and the solution θ^∗ = 2.004 of the corresponding likelihood control are obtained. © 2016, Springer Science+Business Media New York.

关键词： Exponential distribution uniqueness Secant Tea Likelihood distributed parameter

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