Abstract
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.
Highlights
In the actual operation, generator is in normal state, and in abnormal states probably. e static air gap eccentricity is a kind of mechanical fault which is a certain offset between rotor and stator axis
Most of the literatures focus on the electromagnetic characteristics of generator and the vibration characteristics of iron core under air gap eccentricity and interturn short circuit faults, and there are few researches on the electromagnetic force and mechanical response characteristics of stator end winding under this kind of faults
This paper mainly studies the electromagnetic force excitation behaviours and mechanical response of generator stator end winding under the composite electromechanical fault of air gap static eccentricity and rotor interturn short circuit (RISC) and comparatively analyses the characteristics in normal, eccentricity, RISC, and composite fault. e stress result can provide a basis for targeted reverse design, and the deformation distribution is a guidance of wear failure prevention and daily examination
Summary
Generator is in normal state, and in abnormal states probably. e static air gap eccentricity is a kind of mechanical fault which is a certain offset between rotor and stator axis. Most of the literatures focus on the electromagnetic characteristics of generator and the vibration characteristics of iron core under air gap eccentricity and interturn short circuit faults, and there are few researches on the electromagnetic force and mechanical response characteristics of stator end winding under this kind of faults He et al found that the even harmonics increment of the winding electromagnetic force becomes larger with the increase of the SISC degree [22]. This paper mainly studies the electromagnetic force excitation behaviours and mechanical response of generator stator end winding under the composite electromechanical fault of air gap static eccentricity and RISC and comparatively analyses the characteristics in normal, eccentricity, RISC, and composite fault.
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