scholarly journals A Comprehensive Analysis on Transient Electromagnetic Force Behavior of Stator Windings in Turbo-Generator

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Hong-Chun Jiang ◽  
Yu-Ling He ◽  
Gui-Ji Tang ◽  
Ming-Xing Xu
Keyword(s):  
Electromagnetic Force ◽  
Mechanical Response ◽  
Comprehensive Analysis ◽  
Simplified Model ◽  
Force Density ◽  
Stator Core ◽  
Stator Windings ◽  
Fea Model ◽  
Transient Electromagnetic ◽  
Turbo Generator

This paper presents a comprehensive analysis on the transient electromagnetic force behavior of the stator windings in a QFSN-600-2YHG type turbo-generator. Different from other studies, this paper investigates not only the distribution regularities of the resultant force and the force density, but also the force harmonic characteristics, and the mechanical responses which will cause sensitive impact on the insulation wearing. The whole work is generally based on a proposed simplified model and the 3D finite element coupling calculation. The simplified model contains two parts. The first part is the theoretical model that employs the approximate solution of the image current to obtain the analytic formula of the electromagnetic force on the end windings conveniently. The second part is the FEA model that employs only the end windings and one-tenth of the stator core to save the calculating memory and, meanwhile, obtain the qualified electromagnetic force as well as the mechanical response. It is shown that the nose-top, the connection point between the line part and the end part, and the middle of the involute are the three most dangerous positions of the end winding to sustain serious insulation wearing. Moreover, the winding, which endures the maximum mechanical response, is neither always consistent with the one that has the largest resultant electromagnetic force nor directly in accordance with the winding that affords the most intensive electromagnetic force density. The findings in this paper will be beneficial for the insulation monitoring and the manufacturing improvement on the stator windings.

scholarly journals Electromagnetic Force and Mechanical Response of Turbo-Generator End Winding under Electromechanical Faults

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Hong-Chun Jiang ◽  
Yu-Ling He ◽  
Gui-Ji Tang ◽  
Xing-Hua Yuan
Keyword(s):  
Fatigue Failure ◽  
Electromagnetic Force ◽  
Mechanical Response ◽  
Short Circuit ◽  
Three Dimensional ◽  
Distribution Law ◽  
Turbo Generator ◽  
Before And After ◽  
Variation Characteristics ◽  
Static Eccentricity

This paper comparatively studies the electromagnetic force and mechanical response of the end winding before and after 3 kinds of typical electromechanical faults in turbo-generator. The analytical expression of electromagnetic force of end winding is derived under the composite fault of static eccentricity and rotor interturn short circuit. Meanwhile, the three-dimensional transient finite element simulation is carried on, and the frequency composition and amplitude variation characteristics of the radial, axial, and tangential electromagnetic force are analyzed for the end windings under static eccentricity, rotor interturn short circuit, and composite fault. Therefore, it provides a reference for the vibration wear detection and electromagnetic force control of the end winding. Moreover, the maximum stress and deformation of different positions on the end involute are obtained. And the three-directional vibration acceleration characteristics of the end winding are further analyzed. Finally, the distribution law of winding fatigue failure and vibration wear is acquired, which lays a foundation for the reverse suppression of end winding fatigue failure and insulation wear.

Analysis of Vibration Caused by Electromagnetic Force on Stator End-Winding of Large Dry Submersible Motor

2013 ◽  
Vol 416-417 ◽  
pp. 428-432
Author(s):  
Li Shan ◽  
Xiao Wei Cheng ◽  
Yong Fang ◽  
Xiao Hua Bao
Keyword(s):  
Electromagnetic Field ◽  
Steady State ◽  
Transition State ◽  
Electromagnetic Force ◽  
Radial Displacement ◽  
Radial Direction ◽  
Axial Direction ◽  
Axial Displacement ◽  
Force Density ◽  
Submersible Motor

This paper investigates the vibration which caused by electromagnetic on the stator end-winding of the large dry submersible motor. Firstly, the electromagnetic field which included transition state and steady state is researched by 3-D FEM. Secondly, the electromagnetic force which lead to vibrations of end-winding is calculated by numerical method, it can be obtained that where endured the largest force density along the slant part of end-winding. Finally, the radial displacement and the axial displacement of the slant part which caused by vibrations is studied, the analysis results show that the axial displacement is larger than the amplitude of radial displacement. It indicates that the slant part of end-winding will be more easily damaged at axial direction than radial direction.

scholarly journals Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Zhang ◽  
Lin Xu ◽  
Yong Xiao ◽  
NingBo Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Comprehensive Analysis ◽  
High Density ◽  
Electromagnetic Method ◽  
Mine Safety ◽  
Practical Significance ◽  
Time Base ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic

A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.

Electromagnetic Force Density in a Ferromagnetic Material

2004 ◽  
Vol 40 (2) ◽  
pp. 553-556 ◽  
Author(s):  
F. Henrotte ◽  
H.V. Sande ◽  
G. Deliege ◽  
K. Hameyer
Keyword(s):  
Electromagnetic Force ◽  
Ferromagnetic Material ◽  
Force Density

AXIAL ELECTROMAGNETIC FORCE DENSITY IN MPD THRUSTERS

1992 ◽  
Vol 06 (23) ◽  
pp. 1465-1474
Author(s):  
T.S. SHESHADRI
Keyword(s):  
Density Distribution ◽  
Axial Force ◽  
Electromagnetic Force ◽  
Mass Density ◽  
Force Density ◽  
Viscous Effects ◽  
Inlet Velocity ◽  
Large Force ◽  
Hall Parameter ◽  
Mpd Thrusters

An MPD thruster formulation involving coupled aerothermodynamic-electromagnetic equations and including viscous effects is developed and solved. The electromagnetic force density distribution in the thruster interior is studied. Axial force densities are found to be largest on the cathode longitudinal surface. Very large force densities are found at the cathode upstream end and this is attributed to large values of the Hall parameter. Over the rest of the cathode longitudinal surface, axial force densities increase with increasing inlet velocities and mass densities and larger plasma viscosities. Equivalent increases in inlet velocity and mass density produce effects of different magnitudes.

scholarly journals Sensitivity of Axial Velocity at the Air Gap Entrance to Flow Rate Distribution at Stator Radial Ventilation Ducts of Air-Cooled Turbo-Generator with Single-Channel Ventilation

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3442
Author(s):  
Yong Li ◽  
Weili Li ◽  
Ying Su
Keyword(s):  
Flow Velocity ◽  
Calculation Method ◽  
Air Gap ◽  
Test Method ◽  
Distribution Law ◽  
Stator Core ◽  
Flow Phenomenon ◽  
Turbo Generator ◽  
Ventilation Ducts ◽  
Ventilation Duct

In the design and calculation of a 330 MW water-water-air cooling turbo-generator, it was found that the flow direction of the fluid in the local stator radial ventilation duct is opposite to the design direction. In order to study what physical quantities are associated with the formation of this unusual fluid flow phenomenon, in this paper, a 100 MW air-cooled turbo-generator with the same ventilation structure as the abovementioned models is selected as the research object. The distribution law and pressure of the fluid in the stator radial ventilation duct and axial flow velocity at the air gap entrance are obtained by the test method. After the calculation method is proved correct by experimental results, this calculation method is used to calculate the flow velocity distribution of the outlets of multiple radial ventilation ducts at various flow velocities at air gap inlets. The relationship between the flow distribution law of the stator ventilation ducts and the inlet velocity of the air gap is studied. The phenomenon of backflow of fluid in the radial ventilation duct of the stator is found, and then the influence of backflow on the temperature distribution of stator core and winding is studied. It is found that the flow phenomenon can cause local overheating of the stator core.

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