scholarly journals Multifield Calculation and Analysis of Excitation Winding Interturn Short Circuit Fault in Turbo-Generator

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2626 ◽  
Author(s):  
Minghan Ma ◽  
Yonggang Li ◽  
Yucai Wu ◽  
Chenchen Dong
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Temperature Field ◽  
Stress Field ◽  
Short Circuit ◽  
Three Dimensional ◽  
Turbo Generator ◽  
Dimensional Finite Element ◽  
Air Gap Magnetic Field ◽  
Excitation Winding

Excitation winding interturn short circuit (EWISC) is a common fault in turbo-generators. Once the fault occurs, if not handled in time, it will result in significant security risks to the power system. Using the multifield characteristics of fault generators for a comprehensive diagnosis can make the diagnostic results more accurate and credible. In this paper, taking a TA-1100-78 type, two pole pairs turbo-generator as the research object, the two-dimensional finite element electromagnetic model of stator/rotor and the three-dimensional finite element heat transfer model of rotor were established. The electromagnetic field, temperature field, and stress field of the generator were simulated and analyzed. At the same time, the air gap magnetic field, three-dimensional temperature field, and stress field distribution of the rotor were calculated for EWISC faults in different fault degrees and positions. The results showed that the EWISC fault weakened the air gap magnetic field and caused unbalanced electromagnetic distribution. At the same time, it caused a distortion of the rotor temperature field, resulting in an unbalanced distribution of the temperature field. The stress field was affected by the distortion of temperature field, and the local thermal stress increased but did not exceed the yield limit of the material. Restorable elastic deformation occurred when the rotor was heated, which caused the thermal bending of the rotor. The method adopted in this paper can provide a reference for the calculation of multiphysical field after a generator fault. It is also pointed out that the thermal unbalance influence should not be neglected in the study of generator vibration characteristics.

Thermal-stress analysis and calculation of single and dual chip set double-sided circuit board based on three-dimensional finite element algorithm

Circuit World ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 49-54
Author(s):  
Lan Song ◽  
Yang Zhao ◽  
Yaoming Zhou ◽  
Haifei Xiang
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Thermal Stress ◽  
Three Dimensional ◽  
Circuit Board ◽  
Content Type ◽  
Thermal Stress Field ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Element Algorithm

Purpose – The purpose of this paper is to analyze and figure out the temperature field and thermal stress field with the calculation model of thermal insulation material and composite material. Design/methodology/approach – The paper adopted the three-dimensional finite element algorithm. Findings – The simulated results showed great shearing strength between the chipset and the printed circuit board. The position of chip exerts great influence on the distribution of temperature field and thermal stress field of circuit board. The reasonable distribution of chip will effectively reduce the temperature extremum and stress extremum of circuit board. Originality/value – The paper analyzes and presents a discussion of the problems relating to the density of electronic packaging. The analysis process and the method of the paper provide essential help in resolving electronic device heat problems.

scholarly journals 3-D Finite Element Investigation of Flux Regulation Performance of a Novel Hybrid Excitation Brushless Claw-Pole Alternator

2012 ◽  
Vol 614-615 ◽  
pp. 1226-1229
Author(s):  
Dong Wei Qiao ◽  
Xiu He Wang ◽  
Chang Qing Zhu
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Analysis ◽  
Wide Range ◽  
Hybrid Excitation ◽  
Field Control ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Control Principle

In consideration of low power density of electric excitation claw-pole alternator (EECA) and some difficulties in magnetic field regulation of permanent magnet claw-pole alternator (PMCA), a novel hybrid excitation brushless claw-pole alternator (HEBCA) is proposed in this paper. Its structure and field control principle are described. Three dimensional finite element analysis is used to obtain the no-load magnetic field distributions and field control capability under different field currents. The result shows that the flux of the prototype machine can be adjusted over a wide range with a relatively low field current

Void Growth in Elastic-Plastic Materials

1989 ◽  
Vol 56 (2) ◽  
pp. 309-317 ◽  
Author(s):  
C. L. Hom ◽  
R. M. McMeeking
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Pure Shear ◽  
Three Dimensional ◽  
Void Volume ◽  
Strain Behavior ◽  
Finite Strain Theory ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Elastic Plastic Materials

Three-dimensional finite element computations have been done to study the growth of initially spherical voids in periodic cubic arrays. The numerical method is based on finite strain theory and the computations account for the interaction between neighboring voids. The void arrays are subjected to macroscopically uniform fields of uniaxial tension, pure shear, and high triaxial stress. The macroscopic stress-strain behavior and the change in void volume were obtained for two initial void volume fractions. The calculations show that void shape, void interaction, and loss of load carrying capacity depend strongly on the triaxiality of the stress field. The results of the finite element computation were compared with several dilatant plasticity continuum models for porous materials. None of the models agrees completely with the finite element calculations. Agreement of the finite element results with any particular constitutive model depended on the level of macroscopic strain and the triaxiality of the remote uniform stress field.

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