Online estimation of Equivalent Model for cluster of induction generators: A MVMO-based approach

2014 ◽

Vol 494-495 ◽

pp. 1820-1824

Author(s):

Dong Ning Wei ◽

Xue Min Zhang ◽

Jian Min Ye

Keyword(s):

Wind Speed ◽

Wind Farm ◽

Measurement Data ◽

Equivalent Model ◽

Modelling Framework ◽

Induction Generators ◽

Doubly Fed Induction Generators ◽

Wake Model ◽

Basic Characteristics ◽

Doubly Fed

In this paper, a novel modelling approach based on characteristic fusion is proposed and used to build a static equivalent model of wind farm. Firstly, the modelling framework based on characteristic fusion is given. Secondly, the basic characteristics of wind farm including characteristic of wind turbine generator (WTG), wind speed spatial distribution and characteristic of wind farm are analyzed according to the framework. Then detailed modelling process is provided utilizing SVR as a fusion tool. This approach combines the advantages of both mechanism and non-mechanism methods with both satisfactory fitting ability and generalization ability. It only requires the maximum and minimum value of wind speed among the wind farm, rather than accurate wake model as mechanism method nor massive measurement data as non-mechanism method. Numerical simulation indicates the effectiveness and robustness of the proposed method. When available data is reduced or includes bad measurement, the proposed method can still keep favorable performance.

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Impedance seen by Distance Relays on Lines Fed from Fixed Speed Wind Turbines

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2013-0026 ◽

2013 ◽

Vol 14 (1) ◽

pp. 17-24 ◽

Cited By ~ 4

Author(s):

Sachin Srivastava ◽

U.J. Shenoy ◽

Abhinna Chandra Biswal ◽

Ganesan Sethuraman

Keyword(s):

Transmission Line ◽

Wind Turbines ◽

Transmission Lines ◽

Short Circuit ◽

Equivalent Model ◽

Wind Generation ◽

Synchronous Generators ◽

Induction Generators ◽

Squirrel Cage ◽

Distance Relays

Abstract This paper deals with line protection challenges experienced in a system having substantial wind generation penetration. Two types of generators, thermal synchronous generators and fixed speed wind turbines based on squirrel-cage induction generators, are simulated as thevenin equivalent model, connected to grid with single-circuit transmission line. The paper gives comparative discussion and summarizes analytical investigations carried out on the impedance seen by distance relays by varying fault resistances and grid short circuit MVA, for the protection of such transmission lines during faults.

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Determination of the transverse shear stress in layered composites

Industrial laboratory Diagnostics of materials ◽

10.26896/1028-6861-2020-86-2-44-53 ◽

2020 ◽

Vol 86 (2) ◽

pp. 44-53

Author(s):

Yu. I. Dudarkov ◽

M. V. Limonin

Keyword(s):

Shear Stress ◽

Transverse Shear ◽

Composite Beam ◽

Layered Composite ◽

Equivalent Model ◽

Shear Stresses ◽

Transverse Shear Stress ◽

Layered Composites ◽

Laminate Composites ◽

Transverse Shear Stresses

An engineering approach to estimation of the transverse shear stresses in layered composites is developed. The technique is based on the well-known D. I. Zhuravsky equation for shear stresses in an isotropic beam upon transverse bending. In general, application of this equation to a composite beam is incorrect due to the heterogeneity of the composite structure. According to the proposed method, at the first stage of its implementation, a transition to the equivalent model of a homogeneous beam is made, for which the Zhuravsky formula is valid. The transition is carried out by changing the shape of the cross section of the beam, provided that the bending stiffness and generalized elastic modulus remain the same. The calculated shear stresses in the equivalent beam are then converted to the stress values in the original composite beam from the equilibrium condition. The main equations and definitions of the method as well as the analytical equation for estimation of the transverse shear stress in a composite beam are presented. The method is verified by comparing the analytical solution and the results of the numerical solution of the problem by finite element method (FEM). It is shown that laminate stacking sequence has a significant impact both on the character and on the value of the transverse shear stress distribution. The limits of the applicability of the developed technique attributed to the conditions of the validity of the hypothesis of straight normal are considered. It is noted that under this hypothesis the shear stresses do not depend on the layer shear modulus, which explains the absence of this parameter in the obtained equation. The classical theory of laminate composites is based on the similar assumptions, which gives ground to use this equation for an approximate estimation of the transverse shear stresses in in a layered composite package.

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Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) ◽

10.2174/2352096511666180723144119 ◽

2019 ◽

Vol 12 (2) ◽

pp. 190-198

Author(s):

Sunny Katyara ◽

Lukasz Staszewski ◽

Faheem Akhtar Chachar

Keyword(s):

Distributed Generation ◽

Normal Condition ◽

Distribution System ◽

Distribution Networks ◽

Equivalent Model ◽

Stability Factor ◽

Matlab Simulation ◽

The Stability ◽

Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

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Simulation of linear induction generators in hybrid electric vehicle applications

3rd IET International Conference on Power Electronics, Machines and Drives (PEMD 2006) ◽

10.1049/cp:20060150 ◽

2006 ◽

Author(s):

A. Ghaempanah ◽

M. Mirsalim ◽

M. Mirzayee

Keyword(s):

Electric Vehicle ◽

Hybrid Electric Vehicle ◽

Linear Induction ◽

Induction Generators ◽

Hybrid Electric

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Autonomous excitation of induction generators

IEEE Transactions on Magnetics ◽

10.1109/20.668063 ◽

1998 ◽

Vol 34 (3) ◽

pp. 664-670 ◽

Cited By ~ 11

Author(s):

R. Rabinovici

Keyword(s):

Induction Generators

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Direct Power Control of Matrix Converter-Fed DFIG with Fixed Switching Frequency

Sustainability ◽

10.3390/su11092604 ◽

2019 ◽

Vol 11 (9) ◽

pp. 2604 ◽

Cited By ~ 4

Author(s):

Arzhang Yousefi-Talouki ◽

Shaghayegh Zalzar ◽

Edris Pouresmaeil

Keyword(s):

Power Control ◽

Direct Torque Control ◽

Matrix Converter ◽

Torque Control ◽

Switching Frequency ◽

Direct Power ◽

Direct Power Control ◽

Reactive Component ◽

Extensive Discussion ◽

Induction Generators

In this paper, a direct power control (DPC) technique is proposed for matrix converter-fed grid-connected doubly fed induction generators (DFIGs). In contrast to what has been investigated in the past for direct torque control (DTC) or DPC of matrix converter-fed DFIGs, the active and reactive powers are regulated in a fixed switching frequency using indirect space vector modulation (ISVM) technique. Hence, designing input filters for matrix converters (MCs) becomes convenient. In addition, the reactive component of input side of MC is controlled which leads to reduction of distortion in grid current waveform. Also, an extensive discussion is addressed for nonlinear voltage errors of MC that may cause inaccurate power control. Simulation results done in MATLAB/Simulink show the effectiveness of the proposed method.

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