Steam turbine generator magnetic slot wedge

Abstract

The invention discloses a steam turbine generator magnetic slot wedge. A sheet-shape magnetic conductive unit can be used to reduce eddy-current losses of the unit and can be used to change distribution of magnetic lines in a stator groove so that harmonic wave intensity is reduced and an effect of reducing harmonic wave losses is reached. A structure can satisfy a structural stiffness and strength requirement and a requirement of a steam turbine generator air gap electromagnetic force, and purposes of reducing stray losses of the generator, increasing efficiency, increasing a generator performance index and increasing reliability are achieved.

Description

Technical field: [0001] The invention relates to a magnetic slot wedge of a steam turbine generator. Background technique: [0002] The stator core of the generator needs to be slotted to inlay the stator winding. Due to the difference in magnetic permeability, the distribution of the air gap magnetic field changes, forming a pulsation component distributed along the air gap, and eddy current loss is generated on the surface of the generator rotor, which is a stray loss of the generator. The main component of the generator; this phenomenon not only produces loss, reduces the efficiency of the generator, but also causes the surface of the rotor to overheat, increases the temperature rise of the generator, affects the output of the generator and the insulation life; the loss caused by the pulsating component is related to the rated speed of the generator, The number of stator slots, air gap size and other factors are related, and these key parameters are often determined by th...

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Problems solved by technology

[0002] The stator core of the generator needs to be slotted to inlay the stator winding. Due to the difference in magnetic permeability, the distribution of the air gap magnetic field changes, forming a pulsating component distributed along the air gap, and eddy current loss is generated on the surface of the generator rotor, which is a stray loss of the generator. The main component of the generator; this phenomenon not only produces loss, reduces the efficiency of the generator, but also overheats the rotor surface, increases the temperature rise of the generator, affects the output of the generator and the insulation life; the loss caused by the pulsating component is related to the rated speed of the generator, The number of stator slots, air gap size and other factors are related, and these key parameters are often determined by the overall design of the generator and are related to the technical parameters of the generator. For some designs, such as the design of large turbogenerators, especially the number of stator slots Fewer electromagnetic schemes often produce such a contradiction: the loss of the pulsating component exceeds expectations, which reduces the efficiency of the generator; and the technical scheme of increasing the number of stator slots or increasing the size of the air gap can reduce the loss of the pulsating component. But it increases the manufacturing cost or increases the excitation loss, and also changes the performance parameters of the generator

[0003] In response to this problem, magnetic slot wedges are often used to solve this problem on small and medium-sized motors. Magnetic slot wedges can increase the magnetic permeability of the stator notch to reduce the amplitude of the air gap pulsation component, that is, to reduce the loss caused by the pulsation component. ; but this technology also has shortcomings: First, although the magnetic slot wedge can reduce the amplitude of the air gap pulsation component, it also increases the leakage flux component, which brings loss and reduces the performance of the motor. A trade-off must be made in the magnetic permeability of the slot wedge This problem, otherwise it is difficult to achieve the desired effect; on the other hand, the structural design, material selection and manufacturing technology of slot wedges are not mature, such as molded magnetic slot wedges, slot wedges processed by magnetic laminates, induced magnetic slot wedges, and magnetic putty slot wedges. etc., the actual performance can not reach the expected effect, and the magnetic slot wedge is subjected to the alternating stress generated by the magnetic pull of the rotor, which has fatigue problems, and often falls off and damaged, resulting in operational accidents; especially in large turbogenerators, the magnetic pull The role problem is more prominent, so that the magnetic slot wedge technology is still not applied; although the electromagnetic load of large turbogenerator is very high, the structure is compact, the ventilation and cooling are limited, and the reduction of stray loss is particularly important for improving the performance index of the generator, but Reliability and other issues limit the application of magnetic slot wedge technology, making it difficult to break through the technology of reducing stray losses in large turbogenerators

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