Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects
Introduction. An analysis of incidents linked to power units’ emergency disconnecting from network as a result of turbogenerators’ malfunction on the NPP of Ukraine is conducted. It is identified, that the reason of the majority of incidents is an insufficient reliability of the stator winding’s dir...
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| Format: | Article |
| Language: | English |
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National Technical University "Kharkiv Polytechnic Institute"
2023-06-01
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| Series: | Electrical engineering & Electromechanics |
| Subjects: | |
| Online Access: | http://eie.khpi.edu.ua/article/view/265000/276493 |
| _version_ | 1827914550110846976 |
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| author | K. A. Kuchynskyi O. H. Kensytsky |
| author_facet | K. A. Kuchynskyi O. H. Kensytsky |
| author_sort | K. A. Kuchynskyi |
| collection | DOAJ |
| description | Introduction. An analysis of incidents linked to power units’ emergency disconnecting from network as a result of turbogenerators’ malfunction on the NPP of Ukraine is conducted. It is identified, that the reason of the majority of incidents is an insufficient reliability of the stator winding’s direct cooling system. Problem. The most problematic point in winding for today is the frontal parts, where, while cooling is reduced, there are not only thermal, but also thermomechanical loadings on an insulation appearing. The level of these loading depends on structural design of frontal parts and a character of violation of coolant agent circulation in a bar. In some cases they can exceed limit values. The spread and the quality of research on this issue for today are insufficient. Goal. The aim of the completed research is to determine the thermomechanical loading of insulation of stator winding bar in a powerful turbogenerator with a direct liquid cooling under condition when coolant circulation is malfunctioned. Methodology. A complex mathematical model of thermomechanical processes in an insulation of stator winding bar of a powerful turbogenerator is developed. It takes into account the real geometry of the winding bar, variable thermal loading of core elements in radial and axial directions, as well as ways of fixation of slot and frontal winding parts. Studies of thermomechanical processes in an insulation of stator winding bar of turbogenerator are conducted. Results. Values of mechanical displacement and stress for the different modes of malfunction are obtained. Areas of bar, where mechanical loading may exceed the boundaries of mechanical durability of material of insulation of stator winding are identified. With decline of coolant liquid consumption the radial displacement and stress in the winding insulation bar in the area, where the bar exits from the slot are increasing along with that the values of radial stress of insulation of the winding bar in places of frontal parts’ fixation exceed limit values. Practical significance. The offered mathematical models allow to realize calculation experiments and can be used in practice for development and validation of diagnostic systems, analysis, design and investigation of emergency situations during exploitation of turbogenerators on power stations of Ukraine.
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| first_indexed | 2024-03-13T02:45:49Z |
| format | Article |
| id | doaj.art-d06e82c400b845edbfa0b4df81ede689 |
| institution | Directory Open Access Journal |
| issn | 2074-272X 2309-3404 |
| language | English |
| last_indexed | 2024-03-13T02:45:49Z |
| publishDate | 2023-06-01 |
| publisher | National Technical University "Kharkiv Polytechnic Institute" |
| record_format | Article |
| series | Electrical engineering & Electromechanics |
| spelling | doaj.art-d06e82c400b845edbfa0b4df81ede6892023-06-28T19:51:45ZengNational Technical University "Kharkiv Polytechnic Institute"Electrical engineering & Electromechanics2074-272X2309-34042023-06-0120234758210.20998/2074-272X.2023.4.11Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defectsK. A. Kuchynskyi0https://orcid.org/0000-0003-4003-6721O. H. Kensytsky1https://orcid.org/0000-0002-2665-207XInstitute of Electrodynamics of NAS Ukraine, UkraineInstitute of Electrodynamics of NAS Ukraine, UkraineIntroduction. An analysis of incidents linked to power units’ emergency disconnecting from network as a result of turbogenerators’ malfunction on the NPP of Ukraine is conducted. It is identified, that the reason of the majority of incidents is an insufficient reliability of the stator winding’s direct cooling system. Problem. The most problematic point in winding for today is the frontal parts, where, while cooling is reduced, there are not only thermal, but also thermomechanical loadings on an insulation appearing. The level of these loading depends on structural design of frontal parts and a character of violation of coolant agent circulation in a bar. In some cases they can exceed limit values. The spread and the quality of research on this issue for today are insufficient. Goal. The aim of the completed research is to determine the thermomechanical loading of insulation of stator winding bar in a powerful turbogenerator with a direct liquid cooling under condition when coolant circulation is malfunctioned. Methodology. A complex mathematical model of thermomechanical processes in an insulation of stator winding bar of a powerful turbogenerator is developed. It takes into account the real geometry of the winding bar, variable thermal loading of core elements in radial and axial directions, as well as ways of fixation of slot and frontal winding parts. Studies of thermomechanical processes in an insulation of stator winding bar of turbogenerator are conducted. Results. Values of mechanical displacement and stress for the different modes of malfunction are obtained. Areas of bar, where mechanical loading may exceed the boundaries of mechanical durability of material of insulation of stator winding are identified. With decline of coolant liquid consumption the radial displacement and stress in the winding insulation bar in the area, where the bar exits from the slot are increasing along with that the values of radial stress of insulation of the winding bar in places of frontal parts’ fixation exceed limit values. Practical significance. The offered mathematical models allow to realize calculation experiments and can be used in practice for development and validation of diagnostic systems, analysis, design and investigation of emergency situations during exploitation of turbogenerators on power stations of Ukraine. http://eie.khpi.edu.ua/article/view/265000/276493turbogeneratorstator windingwater coolingviolation of circulationthermomechanical loading |
| spellingShingle | K. A. Kuchynskyi O. H. Kensytsky Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects Electrical engineering & Electromechanics turbogenerator stator winding water cooling violation of circulation thermomechanical loading |
| title | Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| title_full | Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| title_fullStr | Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| title_full_unstemmed | Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| title_short | Thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| title_sort | thermomechanical loads of powerful turbogenerator stator winding insulation in the presence of water cooling defects |
| topic | turbogenerator stator winding water cooling violation of circulation thermomechanical loading |
| url | http://eie.khpi.edu.ua/article/view/265000/276493 |
| work_keys_str_mv | AT kakuchynskyi thermomechanicalloadsofpowerfulturbogeneratorstatorwindinginsulationinthepresenceofwatercoolingdefects AT ohkensytsky thermomechanicalloadsofpowerfulturbogeneratorstatorwindinginsulationinthepresenceofwatercoolingdefects |