scholarly journals Effect of Pole Number on Generator End Winding Electromagnetic Force and Mechanical Response before and after RISC

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hong-Chun Jiang ◽  
Yu-Ling He ◽  
Gui-Ji Tang
Keyword(s):  
Electromagnetic Force ◽  
Mechanical Response ◽  
Short Circuit ◽  
Three Dimensional ◽  
Element Simulation ◽  
Before And After ◽  
Variation Characteristics ◽  
Stress And Deformation ◽  
Rotor Winding ◽  
Similarity And Difference

This paper comparatively studies on the end winding electromagnetic force and mechanical response for generators with different numbers of poles. The analytical expression of the end winding electromagnetic force is derived under the rotor winding interturn short circuit (RISC) considering the pole number. Meanwhile, the three-dimensional transient finite element simulation is carried on two generators with one-pair poles and three-pair poles. Then, the frequency composition and amplitude variation characteristics of the radial, axial, and tangential electromagnetic forces are analyzed. Further, the maximum stress and deformation on the end winding are calculated and the similarity and difference of the coil failure law are obtained for two kinds of generators. It is found that RISC will bring odd harmonics to electromagnetic force for one-pair pole generators but it will bring odd and fraction harmonics for multipair pole generators. Moreover, the max mechanical response under RISC will decrease for one-pair pole generators but it will increase for multipair pole generators.

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.

Study on Unbalanced Electromagnetic Force of Turbine-Generator Inter Turn Short Circuit and its Relevant Fault

2013 ◽  
Vol 427-429 ◽  
pp. 230-234
Author(s):  
Wen Jing Zhang ◽  
Yong Gang Li ◽  
Yu Ca Wu
Keyword(s):  
Finite Element ◽  
Fault Diagnosis ◽  
Electromagnetic Force ◽  
Short Circuit ◽  
Turbine Generator ◽  
Element Simulation ◽  
Rotor Winding ◽  
Relationship Of ◽  
Short Circuit Fault ◽  
The Relationship

Inter turn short circuit fault is very common for turbine-generator, which will produce unbalanced electromagnetic force (UEMF) together with its relevant fault, namely dynamic eccentric, on the rotor. After complete finite element simulation by ANSYS, The relationship of rotor winding short positions and short degrees with UEMF were studied. And then, only the dynamic eccentric fault occurs, the relations of dynamic eccentric angles and dynamic eccentric degrees with UEMF were discussed as well. Whats more, by comprehensive consideration of the two faults, the characteristic of the force and its change law were researched. This paper provides a viable path to study the vibration law and fault diagnosis of turbine-generator in multi-source stress.

scholarly journals Electromagnetic Forces and Mechanical Responses of Stator Windings before and after Rotor Interturn Short Circuit in Synchronous Generators

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Gui-Ji Tang ◽  
Hong-Chun Jiang ◽  
Yu-Ling He ◽  
Qing-Fa Meng
Keyword(s):  
Electromagnetic Force ◽  
Mechanical Response ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Element Model ◽  
Stator Winding ◽  
Synchronous Generators ◽  
Mechanical Responses ◽  
Before And After ◽  
Frequency Components

This paper studies the stator winding electromagnetic force behaviors before and after rotor inter-turn short circuit (RISC) in synchronous generator. Different from other studies, this paper not only studies the electromagnetic force characteristics, but also investigates the mechanical responses, the damage regularity, and the countermeasure of the stator winding. Firstly, formulas of electromagnetic force online and end part are obtained. Then, a 3D finite element model of a 3-pair-pole simulation generator is applied to get the electromagnetic force, and the dangerous stator slot is found. Finally, the mechanical response of each end winding is acquired, and especially the directional deformations of nose part are calculated. It shows that the occurrence of RISC will bring in times of rotor rotating frequency components to electromagnetic force, but the DC component and 2p times of rotor rotating frequency components are still the main that will be decreased. Additionally, the winding insulation wear in the same layer is more serious than that in a different layer, nose fatigue fracture begins with the center, and nose insulation wear starts from the top.

scholarly journals Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1252
Author(s):  
Junqing Li ◽  
Luo Wang
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Thermal Deformation ◽  
Short Circuit ◽  
Three Dimensional ◽  
Static Field ◽  
Heat Transfer Theory ◽  
Circuit Fault Diagnosis ◽  
Rotor Winding ◽  
Magnetic Poles

Rotor winding inter-turn short circuit a common fault in hydro-generators. This fault would change the temperature, stress, and other thermal fields of a rotor and threaten the safe operation of the generator. In this paper, the Three Gorges hydro-generator is taken as an example. Mathematical models of three-dimensional temperature field and thermal stress field of rotor magnetic poles are established based on heat transfer theory and solved by finite element method. The temperature field, thermal deformation, and thermal stress distribution of magnetic poles in rotor winding inter-turn short circuit are calculated. On the basis of the calculation, the effects of the different turn numbers and positions of short circuit on the temperature, thermal deformation, and thermal stress of rotor magnetic poles are further studied. It is concluded that the thermal stress of the winding adjacent to the shorted turn would decrease, the thermal stress of the winding farther away from the shorted winding would increase, and so on. The results of this paper can provide references for inter-turn short circuit fault diagnosis and lay a foundation for the further studies of related faults.

Impact of Rotor Inter-Turn Short-Circuit on Generator Rotor Force

2011 ◽  
Vol 143-144 ◽  
pp. 125-131 ◽  
Author(s):  
Yong Gang Li ◽  
Guo Wei Zhou ◽  
Yu Ca Wu ◽  
He Ming Li
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Force ◽  
Short Circuit ◽  
Total Force ◽  
Distribution Law ◽  
Generator Rotor ◽  
Finite Element Software ◽  
Full Force ◽  
Rotor Winding ◽  
Short Circuit Fault

This paper analyzes the calculation method of unbalanced electromagnetic force by rotor winding inter-turn short-circuit fault, analytical calculating method neglects saturation, cogging and other factors, so the calculation accuracy is not high, in order to accurately calculate the magnetic field and the unbalanced electromagnetic force, this paper propose to analyze generator magnetic field by a finite element software Ansys, the obtained magnetic field data are further used to analyze the distributed electromagnetic force and the total force that generator rotor suffered, electromagnetic force distribution law of different slots, different levels of inter-turn short-circuit are got, which provide a basis for further studying the full force on generator rotor.

Miniature Circuit Breaker Electromagnetic Release Simulation and Analysis

2013 ◽  
Vol 392 ◽  
pp. 398-402
Author(s):  
Jun Fang Zhang ◽  
Yao Fang ◽  
Zhi Gang Li ◽  
Yan Yan Luo
Keyword(s):  
Electromagnetic Force ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Three Dimensional ◽  
Short Circuit Current ◽  
Element Model ◽  
Field Analysis ◽  
Iron Core ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

With the three-dimensional field analysis software Ansoft, we establish three-dimensional finite element model of the electromagnetic release, obtain the electromagnetic release static characteristics of electromagnetic force by simulation, and analyze the relationship between the electromagnetic force, the short-circuit current and the air gap size. By Analyzing the dynamic characteristics of moving iron core, different short-circuit currents influence on the velocity and displacement of the moving iron core was gained.

scholarly journals Three-dimensional Discrete Element Simulation of Interaction between Aqueduct and Tunnel

2021 ◽  
Author(s):  
Vahab Sarfarazi ◽  
Hadi Haeri ◽  
Kaveh Asgari
Keyword(s):  
Three Dimensional ◽  
Ground Surface ◽  
Ground Settlement ◽  
Tunnel Wall ◽  
Geometrical Properties ◽  
Maximum Value ◽  
Element Simulation ◽  
Before And After ◽  
Effect Of Support ◽  
Support Lining

In this investigation the effect of interaction between aqueduct and tunnel on the ground settlement has been examined using PFC3D. At first, the calibration of PFC3D was conducted based on UCS test results rendered from three different ground layer. Then intact model with dimension of 70 m × 20 m × 34.5 m (x × y × z) was built. These models are consisted of 8 layers with different mechanical and geometrical properties. Four different configurations for aqueduct were created in four models. Diameter of aqueduct was 2 m and its depth was different in four models. After aqueduct generation, tunnel with diameter of 9 m and length of 20 m was drilled in depth of 22 m. After tunnel drilling, the settlement data of ground surface were picked up. After tunnel simulation, the effect of support lining was investigated on the ground settlement. For this purpose, after each step of tunnel drilling, lining support with diameter of 35 cm was performed. The results show that the maximum value of settlement occurred when aqueduct reach to head of tunnel. Also the safety has maximum value when the distance between aqueduct and tunnel wall was 4.5 m. the ground settlement before and after support lining shows that ground settlement reach to zero by support application.

scholarly journals Effect of Static Rotor Eccentricity on End Winding Forces and Vibration Wearing

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Hong-Chun Jiang ◽  
Gui-Ji Tang ◽  
Yu-Ling He ◽  
Kai Sun ◽  
Wei-Jun Li ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Electromagnetic Forces ◽  
Mechanical Responses ◽  
Electromagnetic Structure ◽  
Strength Failure ◽  
Rotor Eccentricity ◽  
Turbo Generator ◽  
Before And After ◽  
Failure Point ◽  
Stress And Deformation

In order to study the vibration wearing regularity and the strength failure point of stator end windings before and after static rotor eccentricity, the three-dimensional electromagnetic forces and the subsequent mechanical responses are studied in this paper. The electromagnetic force, stress, and deformation on the end winding of the QFSN-600-2YHG turbo-generator are calculated by the finite element method (FEM) through an electromagnetic-structure coupling. The radial vibration characteristics of the winding are verified by experiments. It shows that the vibration wearing in the same layer is more serious than that between two neighboring layers. For different layers, the interphase coils endure a larger wearing risk than the innerphase coils. Inside the same phase, the last coil along the rotating direction has the highest risk of insulation wearing. The occurrence of static rotor eccentricity will significantly increase the electromagnetic forces and the vibration amplitudes on some coils. The end-phase coil which is close to the minimum air-gap point is the most dangerous one due to the lasting overstresses and the intensified deformations.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

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