scholarly journals Analysis of Electromagnetic Force on Rotor End Windings of a 300 MW Variable-Speed Generator Motor for Pumped Storage

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Zhaowei Qiao ◽  
Yutian Sun
Keyword(s):  
Electromagnetic Force ◽  
Large Scale ◽  
Short Circuit ◽  
Element Model ◽  
Variable Speed ◽  
Distribution Map ◽  
3D Finite Element ◽  
Three Phase ◽  
Set Up ◽  
Pumped Storage

The variable-speed generator motor (VSGM) for pumped storage has a cylindrical rotor with three-phase lap or wave windings distributed in slots evenly and fed by a converter. For a large-scale VSGM, the electromagnetic force (EMF) on rotor end windings is an important contributor to distortion, vibration, and even damage of rotor end windings. A 3D finite element model of rotor end region of a 300 MW VSGM is set up. The distribution map of EMF density on involute and nose parts of rotor end windings, under rated load and three-phase short circuit at supersynchronous and subsynchronous speed, is drawn. Furthermore, the amplitude of EMF is calculated, and the radial, tangential, and axial components of EMF are analyzed. The results in this paper will lay a foundation for design of rotor end windings and their support structure.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Numerical Simulation of Intercepting Efficiency on Airbag Active Protection System

2010 ◽  
Vol 156-157 ◽  
pp. 360-366
Author(s):  
Kun Zhong ◽  
Zhong Hua Du ◽  
Liang Zhou ◽  
Li Li Song
Keyword(s):  
Element Model ◽  
Protection System ◽  
Working Process ◽  
3D Finite Element ◽  
Advantages And Disadvantages ◽  
Active Protection ◽  
New Type ◽  
Simulation Results ◽  
Set Up ◽  
Metal Jet

Based on the advantages and disadvantages of existing active protection system, this paper proposes a new type of airbag active protection system. The components and working process of the system is introduced. Then taking the physical process of airbag active protection system against a rocket projectile as an example, a 3D finite element model (FEM) of airbag and rocket projectile is set up. With the assistance of the software LS-DYNA3D, through performing the simulation when the rocket projectile touched the airbag with an angle 30° from the normal interface, the intercepting efficiency is calculated and analyzed in the simulation. Results show that airbag can deform and rupture the metal jet generated by the rocket projectile, thus greatly reduce its armor penetrating effect. Finally, it shows excellent protective effect of the airbag active protection system.

scholarly journals REDUCING SHORT CIRCUIT LEVELS BY USING SYSTEM SPLITTING STRATEGIES

2019 ◽  
Vol 11 (3) ◽  
pp. 309-331
Author(s):  
Assist. Prof. Dr. Inaam I. ALI ◽  
Mohanad Sh. Tarad AL-AASAM
Keyword(s):  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
Short Circuit ◽  
Load Flow ◽  
Controlled Islanding ◽  
Power Stations ◽  
Stable Splitting ◽  
Three Phase ◽  
Proper Splitting

Preliminary studies on Iraqi power system show a significant increase in the short circuit level at some of the grid substations and some power stations. This increasing results from the growth of the power generation and transmission systems in size and complexity. Islanding or splitting is dividing the power system into several islands inorder to reduce short circuit levels and avoiding blackouts. The main islanding problem is determining the location of proper splitting points and load balance and satisfaction of transmission capacity constraints for each islands.This paper mainly introduces new proposed splitting strategies of large-scale power systems by using (PSS™E version 30.3 PACKAGE PROGRAME), such that, make re-interconnection of 400KV super high voltage substation based on three-phase load flow to be minimum flow at splitting point and infeed fault current details method to control short circuit levels in Iraq power system without islanding the power system into isolated islands. Controlled islanding or splitting scheme is frequently considered as the final solution to avoid blackouts of power system.Simulation IEEE-25 bus and Iraqi power system used as the test systems for this method. Furthermore, simulation results show significant effectiveness on reducing short circuit levels with same time give stable splitting islands with same frequency for preventing the system blackouts.

The Short Circuit Electromagnetic Force of the Three-Phase Encapsulated Gas Insulated Bus-Bar

1984 ◽  
Vol PER-4 (6) ◽  
pp. 51-52
Author(s):  
Y. Kanno ◽  
T. Amemiya ◽  
N. Takahashi ◽  
N. Kobayashi
Keyword(s):  
Electromagnetic Force ◽  
Short Circuit ◽  
Three Phase

Investigation of electromagnetic force during short-circuit test in three-phase busbar system

2011 ◽  
Author(s):  
Farhana Mohamad Yusop ◽  
Mohamad Kamarol Mohd Jamil ◽  
Dahaman Ishak ◽  
Muhamad Husaini ◽  
Syafrudin Masri
Keyword(s):  
Electromagnetic Force ◽  
Short Circuit ◽  
Three Phase ◽  
Short Circuit Test

A Static and Dynamic Model of Geared Transmissions by Combining Substructures and Elastic Foundations—Applications to Thin-Rimmed Gears

2006 ◽  
Vol 129 (2) ◽  
pp. 184-194 ◽  
Author(s):  
M. N. Bettaïeb ◽  
P. Velex ◽  
M. Ajmi
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Equations Of Motion ◽  
Hybrid Approach ◽  
Three Dimensional ◽  
Element Model ◽  
3D Finite Element ◽  
Elastic Foundations ◽  
Beam Elements ◽  
Set Up

The present work is aimed at predicting the static and dynamic behavior of geared transmissions comprising flexible components. The proposed model adopts a hybrid approach, combining classical beam elements, elastic foundations for the simulation of tooth contacts, and substructures derived from three-dimensional (3D) finite element grids for thin-rimmed gears and their supporting shafts. The pinion shaft and body are modeled via beam elements which simulate bending, torsion and traction. Tooth contact deflections are described using time-varying elastic foundations (Pasternak foundations) connected by independent contact stiffness. In order to account for thin-rimmed gears, a 3D finite element model of the gear (excluding teeth) is set up and a pseudo-modal reduction technique is used prior to solving the equations of motion. Depending on the gear structure, the results reveal a potentially significant influence of thin rims on both quasi-static and dynamic tooth loading.

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.

Variable-Speed Wind Turbines with Doubly-Fed Induction Generators Part III: Model with the Back-to-back Converters

2003 ◽  
Vol 27 (2) ◽  
pp. 79-91 ◽  
Author(s):  
Vladislav Akhmatov
Keyword(s):  
Wind Turbines ◽  
Short Circuit ◽  
Practical Investigations ◽  
System Stability ◽  
Variable Speed ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Set Up ◽  
Doubly Fed ◽  
Short Circuit Fault

A model of the back-to-back converter is set up and implemented in the simulation tool PSS/E as a user-developed model. This model is applied with that of the doubly-fed induction generator (DFIG), described in previous parts of this work [parts II and I]. The latter models variable-speed wind turbines in power stability investigations. Subjected to a short circuit fault, there will be a risk of converter blocking, followed by tripping of the wind turbine [1, 3]. The main reasons of blocking are over-current in the rotor converter and over-voltage in the dc-link. The DFIG model, with representation of the back-to-back converter, results in (a) more accurate replication of the current in the rotor converter and (b) improved computation of the dc-link voltage. These improvements are compared with the model with representation of the rotor converter only. Hence, the DFIG model with representation of the back-to-back converters might be preferred, in practical investigations of power system stability, to models with representation of the rotor converter only.

scholarly journals Stator Flux-Regulatory Excitation Control in Converter-Fed Synchronous Machines for Pumped-Storage Variable-Speed Hydropower

2021 ◽  
Author(s):  
Jørgen Hagset Stavnesli ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Large Scale ◽  
Optimal Operation ◽  
Hydropower Plant ◽  
Technical Solution ◽  
Saturation Curve ◽  
Variable Speed ◽  
Original Design ◽  
Machine Loading ◽  
Stator Flux ◽  
Pumped Storage

Pumped-storage hydropower is seen as a promising solution for efficient, large-scale energy storage. One competitive technical solution is the variable-speed hydropower plant (VSHP) configured with a converter-fed synchronous machine (CFSM). These machines are operated with one extra degree of freedom that is not usually optimized, where the CFSM's rotor-side DC excitation interacts with the stator-side AC excitation. Depending on machine loading, the CFSM will be utilized in conditions far from its original design. In order to deal with this issue, this paper presents a stator flux control (SFC) method for regulating VSHPs in a more efficient way by adjusting the field current to prevent the machine from operating with over-magnetization independent of loading condition, as well as better utilizing the stator-fed converter current, maximizing the utilization of the CFSM. The derived first-principle analytical equations for the proposed SFC have been validated and analyzed in the Matlab/Simulink environment for a large 45 MVA, 375 rpm CFSM, with the measured saturation curve as input. Finally, dynamic transitions between different levels of pumping power reveal the SFC's ability to help to maintain a unity stator flux in the machine, enabling optimal operation independent of loading level.

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