End-winding Structure Research Articles

Modern methods to monitor end winding vibrations in turbo-generators

PurposeProblems caused by end winding vibrations in power plant generators have become increasingly evident in recent years and reveal a need for monitoring and diagnostic systems. An increasing number of operational outages are caused by failures of the winding insulation or the conductor itself due to end winding vibrations. Meanwhile, it is clear that the condition of the end winding must be continuously monitored during operation to detect ineffective end winding support in time and to plan the repair.Design/methodology/approachIn this paper, the complex and nonlinear excitation mechanisms in large machines are presented and modern methods for vibration monitoring are described. Through a consistent use of vibration monitoring in the end winding area as well as the vibration diagnosis done by experts, damage mechanisms can be detected at an early stage, repair measures can be planned and serious damage owing to a weakened main insulation can be avoided.FindingsBy combining modal analysis and trend monitoring in relation to the learned vibration behaviour, the end winding condition can be assessed in a differentiated manner and changes in the end winding structure can be detected early.Originality/valueFinally, an assessment for a two-pole, air-cooled turbo generator is proposed.

Optimization of Generator Stator End Winding Structure Based on Improved PSO and SVM

The selection of parameters in the support vector machine (SVM) approximation model plays an important role in the performance of the model. Therefore, the support vector machine parameters need to be optimized. Because the particle swarm algorithm is easy to be premature and easy to fall into the local optimal solution, the improved particle swarm optimization algorithm is used to optimize the parameters, and the support vector machine approximation model with optimal parameters is established. Finally, the support vector machine approximation model of optimal parameters and particle swarm optimization algorithm are combined and used in the optimization of stator end winding structure of large steam turbine generator. The validity of the method is verified by the analysis of the results, and good optimization results are obtained.

End Space Heat Transfer Coefficient Determination for Different Induction Motor Enclosure Types

In this paper, the determination of the end space induction motor heat transfer coefficients is presented, and the methodologies used are examined closely. Two ldquo <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ad</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">hoc</i> rdquo prototypes have been built and a test bench completed. This paper reports the setup of the test procedures and results obtained in detail. As the end windings are the hottest points of the motor, particular care has been devoted to the determination of the heat transfer coefficient concerning the end-winding structure. The results obtained are of fundamental importance for the determination of the thermal resistances between end windings and end caps. These can then be used in thermal networks usually adopted in thermal model analysis.