Rotor pole non-roundness detection of salient pole synchronous generator based on leakage flux diversion effect

• Published in: Dianji yu Kongzhi Xuebao = Electric Machines and Control Vol. 29; no. 7; p. 1
• Main Authors: Wu, Yucai, Liu, Yanze, Ye, Chao, Zhou, Tianhua, Yang, Guangyong, Bai, Yuhui
• Format: Journal Article
• Language: Chinese; English
• Published: Harbin Harbin University of Science and Technology 01.01.2025
• Subjects: Fault detection; Faults; Frequency spectrum; Induced voltage; Magnetic fields; Magnetic flux; Magnetic poles; Real time; Rotors; Roundness; Stators; Synchronous machines
• ISSN: 1007-449X
• DOI: 10.15938/j.emc.2025.07.001

When the non-roundness of the rotor pole in a large salient pole synchronous generator exceeds the permissible limit, it can lead to severe vibrations of the stator core, stator scrapping rotor, and other operational failures. This fault displays distinct characteristics in the generator's leakage magnetic field. Accurate collection and analysis of magnetic flux leakage signals from the external frame enable the online detection of rotor magnetic pole non-roundness. Firstly, the air gap magnetic field characteristics of the rotor pole in different concave and convex shapes were analyzed. The leakage flux spectrum of the generator's external frame reveals a fault criterion for rotor pole non-roundness, specifically the k/p-order harmonic component. Secondly, it was proposed to fit the U-shaped core tightly on the frame, create a diversion circuit to enhance leakage flux, and analyze the measuring coil's induced voltage frequency spectrum to detect rotor pole non-roundness faults in real-time. Finally, the fault simulation experiment on a salient pole synchronous generator set was complete. Results show that the amplitudes of the 1/2-order and 3/2-order harmonic components of the induced voltage spectrum increased with worsening faults, effectively detecting non-roundness faults in the rotor pole.