Simulation for Design Purposes of Magnetic Fields in Turbogenerators with Asymmetrical and Symmetrical Rotors Part II - Model Calibration and Applications

Demerdash, Nabeel A. O.; Hamilton, H. B.

doi:10.1109/tpas.1972.293529

Cited by 13 publications

(4 citation statements)

References 5 publications

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“…For decades, the internal fault digital research methods of the stator winding of synchronous generator can be divided into the following categories: symmetrical components, phase coordinate method, multi-loop analysis and finite element method [8][9][10][11][12]. Symmetrical components which can be see that three-phase current is superimposed by positive sequence components, negative sequence component and zero sequence component.…”

Section: The Calculation Of Transient Negative Sequence Componentmentioning

confidence: 99%

Study on Transient Negative Sequence Current Calculation and Harmonics Characteristic Analysis for Nuclear Half-Speed Turbine Generator

Dong¹,

Ge²,

Liang³

2015

IJHIT

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In recent years, with the rapid development of China's nuclear power industry, nuclear generator has also been actively developed. Because the unit capacity of the generator is increasing, so working life and operational reliability of the generator are also being tested. Among them, transient thermal running ability of the generator is one of the key factors affecting working life and operational reliability of the generator. This paper mainly analyzed the negative sequence current and the transient negative sequence component of the generator during asymmetric operation, and elaborates the principle of the generator negative sequence component harmonic. The paper has reference value for in-depth study of the generator negative sequence component.

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Section: The Calculation Of Transient Negative Sequence Componentmentioning

confidence: 99%

Study on Transient Negative Sequence Current Calculation and Harmonics Characteristic Analysis for Nuclear Half-Speed Turbine Generator

Dong¹,

Ge²,

Liang³

2015

IJHIT

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“…Thus produced radial rotating force wave is briefly described by (5). where, rm σ denotes the amplitude of the force wave, r ω is the angular frequency, and m is the mode order for the force wave.…”

Section: Analytical and Fem Computationsmentioning

confidence: 99%

“…The main contribution of the above sources is in the form of radial air gap forces in the motor. As mentioned, analyzing these forces numerically is still a challenging task [5], [6].…”

Section: Introductionmentioning

confidence: 99%

Design and analysis of asymmetrical rotor for induction motors

Chitroju

Sadarangani

2008

2008 18th International Conference on Electrical Machines

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Increase of stray losses in the skewed rotor is mainly due to the cross-currents flowing from the conductor into the laminations. These losses are strongly related to the contact resistance between the bar and the laminations which depends on several factors including the casting process. A substantial reduction of cross-current losses can be achieved by changing or removing skew and by employing various slot combinations. Skew removal will cause some parasitic effects such as increase in the noise level and undesirable dips in the starting torque characteristics. To minimize these effects the rotor design needs to be modified and this could be achieved by introducing modulated slots. Two such types of modulated rotor slot designs are proposed in this paper. As a first step in the performance analysis, magnetic forces, which are the major sources of noise and vibration excitations, is considered. In order to study the newly proposed modulated slot designs, a spectral method is employed and analytically calculated electromagnetic forces are validated against FEM results. The analyses shows that the proposed new designs have better force characteristics compared to the conventional design, which illustrate the fact that better performance characteristics can be achieved by removing skew and introducing modulated slots.

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“…dXa v,(oc) = e, = -d t (7) and, from (5), it can be written as: (8) (12) is plotted in Figure 8. Table 6 shows the harmonic contents of this line-to-neutral open-circuit voltage waveform.…”

Section: The Open-circuit Armature Voltage Under Unsaturated and Satumentioning

confidence: 99%

Coupled finite-element/state-space modeling of turbogenerators in the abc frame of reference-the no-load case

Chaudhry

Ahmed-Zaid

Demerdash

1995

IEEE Trans. On energy Conversion

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This first of two companion papers centers on applying a coupled finite-element/state-space technique to the determination of self and mutual winding inductances of a 733-MVA turbogenerator and computing its open-circuit characteristic, in the natural abc frame of reference. In this method, the apparent self and mutual inductance profiles of the armature and field windings, expressed as functions of rotor position angle, are computed from a series of magnetic field solutions performed at uniformly-distributed samples of rotor positions covering the entire 360° electrical cycle, using the energy perturbation method. These inductances, which are obtained at no-load for three different excitation levels, include the full effect of space harmonics introduced by the magnetic circuit geometry, winding layouts and magnetic circuit saturation. The abc-frame/finite-element computed open-circuit characteristic is in excellent agreement with the test results. This computed no-load set of parameters forms the initial data for simulation of the full-load performance given in the companion paper, including the full impact of space harmonics and saturation on the flux linkage, current and voltage waveforms, and other performance parameters.Keywords-Finite Elements, Turbogenerators, ABC Frame of Reference, Inductances and Reactances of Machines. I N T R O D U C T I O NSynchronous machine models used in stability studies are usually formulated under the well-known two-axis theory by transforming (a,b,c) stator variables into fictitious direct (d) and quadrature (9) axes variables. The parameters in these models are normally determined from standard open-circuit and short-circuit tests, load rejection tests, or from frequency-response measurements [I,2]. In all of these methods, saturation effects are approximated by empirical formulas which, in many cases, yield results with reasonable engineering accuracy [3]. It is recognized, however, that only a full detailed magnetostatic field solution of Maxwell's equations can accurately reflect the impact of rotor saliency, slotting, rotor-to-stator relative motion, saturation, winding layouts and other effects.by t h e IEEE E l e c t r i c Machinery Committee of t h e IEEE Power Engineering S o c i e t y f o r p r e s e n t a t i o n a t t h e IEEE/PES 1994 Summer Meeting, San F r a n c i s 1993; made a v a i l a b l e f o r p r i n t i n g June 1 , 1994.A paper recommended and approved Two-dimensional (2D) finite-element (FE) and finitedifference (FD) methods have been shown t o be a viable alternative for obtaining synchronous machine parameters numerically [4-81. These developments in the F E and F D methods were based on work [5-81 where the magnetic field in turbogenerators under load was modeled with the help of a tworeaction (d-q) theory-based method. In these works, the stator (a,b,c) phase coils and currents were largely modeled by sinusoidal current sheets from which the stator slot (armature) currents were obtained. More recently, coupled 3D-FE/statespace (CFE-SS) models in t...

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Simulation for Design Purposes of Magnetic Fields in Turbogenerators with Asymmetrical and Symmetrical Rotors Part II - Model Calibration and Applications

Cited by 13 publications

References 5 publications

Study on Transient Negative Sequence Current Calculation and Harmonics Characteristic Analysis for Nuclear Half-Speed Turbine Generator

Study on Transient Negative Sequence Current Calculation and Harmonics Characteristic Analysis for Nuclear Half-Speed Turbine Generator

Design and analysis of asymmetrical rotor for induction motors

Coupled finite-element/state-space modeling of turbogenerators in the abc frame of reference-the no-load case

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