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American Control Conference

作者： Fengyu Zhou James Anderson Steven H. Low California Institute of Technology Pasadena CA 91125

ISBN: (纸本)9781538679012;9781538679265

We consider the problem of privately releasing aggregated network statistics obtained from solving a DC optimal power flow (OPF) problem. It is shown that the mechanism that determines the noise distribution parameters are linked to the topology of the power system and the monotonicity of the network. We derive a measure of "almost" monotonicity and show how it can be used in conjunction with a linear program in order to release aggregated OPF data using the differential privacy framework.

关键词： monotonicity program sequence optimal load flow power systems Privacy linear programming topology distributed parameter CONJUNCTION

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A Performance and Stability Analysis of Low-inertia Power Grids with Stochastic System Inertia

A Performance and Stability Analysis of Low-inertia Power Gr...

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American Control Conference

作者： Yi Guo Tyler H. Summers The University of Texas at Dallas Richardson TX USA

ISBN: (纸本)9781538679012;9781538679265

Traditional synchronous generators with rotational inertia are being replaced by low-inertia renewable energy resources (RESs) in many power grids and operational scenarios. Due to emerging market mechanisms, inherent variability of RESs, and existing control schemes, the resulting system inertia levels can not only be low but also markedly time-varying. In this paper, we investigate performance and stability of low-inertia power systems with stochastic system inertia. In particular, we consider system dynamics modeled by a linearized stochastic swing equation, where stochastic system inertia is regarded as multiplicative noise. The H_2 norm is used to quantify the performance of the system in the presence of persistent disturbances or transient faults. The performance metric can be computed by solving a generalized Lyapunov equation, which has fundamentally different characteristics from systems with only additive noise. For grids with uniform inertia and damping parameters, we derive closed-form expressions for the H_2 norm of the proposed stochastic swing equation. The analysis gives insights into how the H_2 norm of the stochastic swing equation depends on 1) network topology;2) system parameters;and 3) distribution parameters of disturbances. A mean-square stability condition is also derived. Numerical results provide additional insights for performance and stability of the stochastic swing equation.

关键词： Power grids Inertial forces Performance metrics Stochastic Stability analysis MOMENT OF INERTIA Damping ratio Lyapunov equation distributed parameter Network topology System dynamics System performance system parameter

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Influence of Power Line parameters on Their Properties

Influence of Power Line Parameters on Their Properties

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International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)

作者： Josifs Survilo Institute of Power Engineering Riga Technical University (RTU) Azenes Str. 12/1 Riga Latvia

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.

关键词： power cables two-port networks two-port networks distributed parameter Power cables electrical quantities propagation factor arcsinh Parallel Lines circuit parameter reactance harbors permittance

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The Effect of distributed parameters on Conducted EMI from DC-Fed Motor Drive Systems in Electric Vehicles

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ENERGIES 2017年第1期10卷 1页

作者： Zhai, Li Lin, Liwen Zhang, Xinyu Song, Chao Beijing Inst Technol Natl Engn Lab Elect Vehicle Beijing 100081 Peoples R China Beijing Inst Technol Coinnovat Ctr Elect Vehicles Beijing Beijing 100081 Peoples R China Beijing Inst Radio Metrol & Measurement Beijing 100854 Peoples R China

The large dv/dt and di/dt outputs of power devices in DC-fed motor drive systems in electric vehicles (EVs) always introduce conducted electromagnetic interference (EMI) emissions and may lead to motor drive system energy transmission losses. The effect of distributed parameters on conducted EMI from the DC-fed high voltage motor drive systems in EVs is studied. A complete test for conducted EMI from the direct current fed(DC-fed) alternating current (AC) motor drive system in an electric vehicle (EV) under load conditions is set up to measure the conducted EMI of high voltage DC cables and the EMI noise peaks due to resonances in a frequency range of 150 kHz-108 MHz. The distributed parameters of the motor can induce bearing currents under low frequency sine wave operation. However the impedance of the distributed parameters of the motor is very high at resonance frequencies of 500 kHz and 30 MHz, and the effect of the bearing current can be ignored, so the research mainly focuses on the distributed parameters in inverters and cables at 500 kHz and 30 MHz, not the effect of distributed parameters of the motor on resonances. The corresponding equivalent circuits for differential mode (DM) and common mode (CM) EMI at resonance frequencies of 500 kHz and 30 MHz are established to determine the EMI propagation paths and analyze the effect of distributed parameters on conducted EMI. The dominant distributed parameters of elements responsible for the appearing resonances at 500 kHz and 30 MHz are determined. The effect of the dominant distributed parameters on conducted EMI are presented and verified by simulation and experiment. The conduced voltage at frequencies from 150 kHz to 108 MHz can be mitigated to below the limit level-3 of CISPR25 by changing the dominant distributed parameters.

关键词： electric vehicle DC-fed motor drive system conducted electromagnetic interference (EMI) distributed parameter

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Open-loop implementation of feedbacks in parametric optimization problems for incompletely determined systems with distributed parameters

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JOURNAL OF COMPUTER AND SYSTEMS SCIENCES INTERNATIONAL 2016年第3期55卷 365-379页

作者： Rapoport, E. Ya. Samara State Tech Univ Ul Molodogvardeiskaya 244 Samara 443100 Russia

A constructive method for the design and real-time implementation of parameterized open-loop controls in the optimal feedback control of ensembles of trajectories of incompletely determined parabolic systems with distributed parameters is proposed. This method uses reduction to semiinfinite optimization problems, alternance properties of their solutions, and additional information about fundamental laws of the application domain. The practical application of the results is illustrated by the example of controlling nonstationary temperature fields under multiple disturbances, which is a problem of independent interest.

关键词： Parametric trajectory Feedback optimal feedback control distributed parameter Temperature fields Ensembles extra message

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WC GRAIN-SIZE DISTRIBUTION

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INTERNATIONAL JOURNAL OF POWDER METALLURGY 2017年第2期53卷 39-47页

作者： Roebuck, Bryan Mingard, Ken P. Natl Phys Lab Mat Div Hampton Rd Teddington TW11 0LW Middx England

The history of grain-size distribution measurements for WC-Co hardmetals is reviewed with an emphasis on measurements of the WC grain-size at the high end of the distribution. The relevance of this aspect of the grain-size parameter is assessed with regard to its likely influence on strength and fatigue measurements. A computer model is used to investigate aspects of the distribution parameters and some comments are made regarding measurements in 2D and 3D microstructures to shed light on the requisite metrology for relevant measurements of WC grain-size distributions.

关键词： hard metal metrology distributed parameter aspect Particle size distribution size distribution

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Mechanisms of surface alloy segregation on faceted core-shell nanowire growth

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JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2017年 100卷 21-44页

作者： Zhang, Qian Voorhees, Peter W. Davis, Stephen H. Northwestern Univ Dept Engn Sci & Appl Math 2145 Sheridan Rd Evanston IL 60208 USA Northwestern Univ Dept Mat Sci & Engn 2225 Campus Dr Evanston IL 60208 USA

A general two-dimensional faceted model that accounts for capillarity and deposition of an A(x)B(1-x) alloy is developed for the growth of the shell on a hexagonal core. With this model, the surface alloy segregation and morphological evolution in the processes of the faceted core-shell nanowire growth are studied both analytically and numerically. Mechanisms of formation of Al-rich stripes along {112} facets and Al-poor quantum dots/wires at the apices of {112} facets are identified. More specifically, it is found that diffusion tends to move the atoms from {112} facets to {110} facets. The formation of Al-rich stripes along the {112} facets is due to the large ratios of mobilities of Al atoms and Ga atoms on {112} facets, even though Al atoms diffuse slower than Ga on the {110} facets. In addition, the difference of interaction parameters in the enthalpy on different facets can also lead to lines of enhanced concentration of Al behind {112} facets. If the attachment rates of Al on the {112} facets are smaller than that on {110} facets, Al-poor dots will grow at the end of the Al-rich stripes because the growth process switches from diffusion dominant to deposition dominant when the size of the nanowire gets large. Moreover, influences of different parameters on the distribution of concentrations of the atoms in the shell are investigated in details.

关键词： Interaction parameters Gallium flat surfaces Atoms linear patterned slopes Stripes aluminium Nanowire capillarity distributed parameter shelling surface alloy

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A NOVEL TRANSMISSION LINE PILOT PROTECTION PRINCIPLE BASED ON FREQUENCY-DOMAIN MODEL IDENTIFICATION OF distributed parameter

A NOVEL TRANSMISSION LINE PILOT PROTECTION PRINCIPLE BASED O...

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IET International Conference on Developments in Power System Protection

作者： J. L. Suonan C. Q. Wang Z. B. Jiao School of Electrical Engineering Xi'an Jiaotong University

ISBN: (纸本)9781622761050

This paper proposes a novel transmission line protection scheme based on frequency-domain model identification method with distributed parameter. Integrated impedance is defined by voltages and currents of two end terminals of transmission line. By analyzing the frequency-domain expressions of integrated impedance in internal and external fault states, the amplitude-frequency characteristics of the integrated impedance are discussed. The integrated impedance in internal fault state shows system impedance characteristic and the integrated impedance in external fault state shows the line distributed capacitive characteristic. The frequency-domain model errors are defined as unbalanced currents respectively in order to identify the internal and external faults. Matrix pencil algorithm is used to calculate the phasors in different frequencies in the proposed scheme. Protection criterions are designed and some tests are performed. The simulation results show that the proposed schemes can detect internal fault quickly and reliably. Furthermore, the influences from capacitive currents and transition resistances can be avoided in the proposed protection scheme.

关键词： distributed parameter Frequency-domain model identification Pilot protection Integrated impedance Matrix pencil algorithm

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Impact of distributed parameters on conducted EMI in electric vehicles motor drive system

Impact of distributed parameters on conducted EMI in electri...

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Applied Energy Symposium and Summit - Low Carbon Cities and Urban Energy Systems (CUE)

作者： Zhai, Li Zhang, Xinyu Gao, Xinjie Lee, Guangzhao Zou, Ming Sun, Tianmin Beijing Inst Technol Zhongguancun South St 5 Beijing 100081 Peoples R China Beijing Elect Vehicle Co LTD Caiyu Econ Dev Zone Caihe St 1 Beijing 102606 Peoples R China

The effect of distributed parameters on conducted EMI is investigated in its motor drive system under load conditions for an electric vehicle. A conducted EMI testing platform was constructed for the system. By testing the conducted EMIs from the system under both load and idle conditions, the propagation paths of both high-and-low frequency differential-mode noise and common-mode interference were analyzed and the equivalent circuits were established. In frequency domain, the mechanism of the conducted EMIs was studied and the effect of distributed parameters on them was discussed. Tests show that high-frequency conducted EMI can be reduced by properly enlarging the distributed capacitances both between ground and power devices in the motor controller and between ground and dc-bus. (C) 2016 Published by Elsevier Ltd.

关键词： electric vehicles motor drive system conducted electromagnetic interference distributed parameter

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On the Bayesian Stability in the Empirical Bayesian Approach

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Journal of Mathematical Sciences (United States) 2017年第2期227卷 161-168页

作者： Drozhzheva, O.V. Concern “Avtomatika ” Moscow Russian Federation

The empirical Bayesian approach is considered for Bayesian stable families of prior parameter distributions. It is shown that in these cases the derivation of the estimate for the Bayesian decision function is considerably simplified. We consider a generalization of the Deely–Lindley’s Bayesian approach to the problem of empirical Bayesian estimation, and present examples of application of the obtained results. © 2017, Springer Science+Business Media, LLC.

关键词： indium decision function Bayesian inference Generalization Bayes methods Tea distributed parameter

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