Computations of Magnetic Field Anomalies in Synchronous Generator Due to Rotor Excitation Coil Faults

Fišer, Rastko; Lavric, Henrik; Bugeza, M.; Makuc, Danilo

doi:10.1109/tmag.2013.2244864

Cited by 14 publications

(9 citation statements)

References 12 publications

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“…According to the symmetry, they determined if a turn-to-turn short circuit occurred. Rastko Fišer et al [5] proposed installing a small magnetic flux probe on the stator core "tooth unit". This allowed users to confirm the short circuit's position in the rotor winding using the difference in induced voltages on the probe according to the corresponding slots in the normal pole and the fault pole.…”

Section: Introductionmentioning

confidence: 99%

Anti-Interference and Location Performance for Turn-to-Turn Short Circuit Detection in Turbo-Generator Rotor Windings

2019

Energies

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Online and location detection of rotor winding inter-turn short circuits are an important direction in the field of fault diagnosis in turbo-generators. This area is facing many difficulties and challenges. This study is based on the principles associated with the U-shaped detection coil method. Compared with dynamic eccentricity faults, the characteristics of the variations in the main magnetic field after a turn-to-turn short circuit in rotor windings were analyzed and the unique characteristics were extracted. We propose that the degree of a turn-to-turn short circuit can be judged by the difference in the induction voltage of the double U-shaped detection coils mounted on the stator core. Here, the faulty slot position was determined by the local convex point formed by the difference in the induced voltage. Numerical simulation was used here to determine the induced voltage characteristics in the double U-shaped coils caused by the turn-to-turn short circuit fault. We analyzed the dynamic eccentricity fault as well as combined the fault of a turn-to-turn short circuit and dynamic eccentricity. Finally, we demonstrate the positive anti-interference performance associated with this fault detection method. This new online detection method is satisfactory in terms of sensitivity, speed, and positioning, and overall performance is superior to the traditional online detection methods.

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Section: Introductionmentioning

confidence: 99%

Anti-Interference and Location Performance for Turn-to-Turn Short Circuit Detection in Turbo-Generator Rotor Windings

2019

Energies

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“…The fault causes the increase of generator excitation current, the relative decline of reactive power and the severe vibration of the unit , even may cause a one‐point ground fault or two‐point ground fault, burning the journal and bearing bush. In recent years, positive progresses have been made in the study of electromagnetic characteristics of the excitation winding inter‐turn short circuit fault, and a series of online detection methods based on electromagnetic characteristics have been put forward, such as detection coil method , excitation current method , shaft voltage method , end leakage flux method , stator parallel branch circulation method , virtual power method and expected electromotive force method .…”

Section: Introductionmentioning

confidence: 99%

Vibration characteristic analysis of rotor in excitation winding inter‐turn short circuit state of turbo generator

et al. 2019

IEEJ Transactions Elec Engng

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The distribution characteristics of fault electromagnetic field and temperature field and the unbalanced stresses on the rotor could be obtained through establishing a three-dimensional model of the rotor and two-dimensional models of the stator and rotor, and respectively solving the electromagnetic field and the temperature field of excitation winding inter-turn short circuit fault by using the finite element analysis method. Two kinds of unbalanced stresses can be respectively equivalent to the unbalanced masses on the rotor surface. The equivalent centrifugal forces as excitation are added into the rotor dynamic equation, and solving the dynamic equation of the rotor by means of Newmark can finally obtain the rotor vibration response. The results show that the fault will cause the changes of amplitude and phase of rotor fundamental frequency vibration. So the amplitude and phase difference of the rotor fundamental frequency vibration can be used as the fault criterion in order to make an accurate diagnosis of excitation winding inter-turn short circuit fault.

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“…It deepens the fault mechanism of EWISC and lays a foundation for fault monitoring based on mechanical characteristics. References [17][18][19] use different detection coils to monitor variations in the main magnetic field of the generator. The distorted air gap magnetic field will induce even or fractional characteristic harmonics voltage in the detection coil.…”

Section: Introductionmentioning

confidence: 99%

Multifield Calculation and Analysis of Excitation Winding Interturn Short Circuit Fault in Turbo-Generator

et al. 2018

Energies

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Excitation winding interturn short circuit (EWISC) is a common fault in turbo-generators. Once the fault occurs, if not handled in time, it will result in significant security risks to the power system. Using the multifield characteristics of fault generators for a comprehensive diagnosis can make the diagnostic results more accurate and credible. In this paper, taking a TA-1100-78 type, two pole pairs turbo-generator as the research object, the two-dimensional finite element electromagnetic model of stator/rotor and the three-dimensional finite element heat transfer model of rotor were established. The electromagnetic field, temperature field, and stress field of the generator were simulated and analyzed. At the same time, the air gap magnetic field, three-dimensional temperature field, and stress field distribution of the rotor were calculated for EWISC faults in different fault degrees and positions. The results showed that the EWISC fault weakened the air gap magnetic field and caused unbalanced electromagnetic distribution. At the same time, it caused a distortion of the rotor temperature field, resulting in an unbalanced distribution of the temperature field. The stress field was affected by the distortion of temperature field, and the local thermal stress increased but did not exceed the yield limit of the material. Restorable elastic deformation occurred when the rotor was heated, which caused the thermal bending of the rotor. The method adopted in this paper can provide a reference for the calculation of multiphysical field after a generator fault. It is also pointed out that the thermal unbalance influence should not be neglected in the study of generator vibration characteristics.

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Computations of Magnetic Field Anomalies in Synchronous Generator Due to Rotor Excitation Coil Faults

Cited by 14 publications

References 12 publications

Anti-Interference and Location Performance for Turn-to-Turn Short Circuit Detection in Turbo-Generator Rotor Windings

Anti-Interference and Location Performance for Turn-to-Turn Short Circuit Detection in Turbo-Generator Rotor Windings

Vibration characteristic analysis of rotor in excitation winding inter‐turn short circuit state of turbo generator

Multifield Calculation and Analysis of Excitation Winding Interturn Short Circuit Fault in Turbo-Generator

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