Calculation of Unbalanced Magnetic Pull in a Salient-Pole Synchronous Generator Using Finite-Element Method and Measured Shaft Orbit

Žarko, Damir; Ban, Drago; Vazdar, Ivan; Jarić, Vladimir

doi:10.1109/tie.2011.2160515

Cited by 56 publications

(40 citation statements)

References 27 publications

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“…Finally two diagnostic methods (i.e., practical operative procedures: ICSVSA and ICSVAT as shown below) were defined for on-line generator monitoring [19], [20]. 4. Development of virtual instruments for RE monitoring: the diagnostic methods were applied through virtual instruments for on-line monitoring of the laboratory machine [9].…”

Section: Theoretical Evaluation Of Numerical/experimental Resultsmentioning

confidence: 99%

“…So misaligned/unbalanced rotors account for about 50% of all fault conditions at the origin of industrial down-times. Shaft unbalances/misalignments can produce a stator-rotor rub resulting in damages to stator and rotor windings and cores in the worst case [1]- [3], but more frequently they lead to bearing overheating and abnormal wear due to the unbalanced magnetic pull (UMP) [4], or even to bearing fault due to vibrations and shaft currents [5]. In 2005 the Italian Navy carried out a report of failures specifically related to mechanical problems of onboard-ship generators, and the actual check and maintenance procedures underwent a critical revision.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

DIEM project's outcomes: An automated air-gap monitoring approach for Italian Navy's on-board low-voltage generators

Bruzzese

Mazzuca

2012

2012 Electrical Systems for Aircraft, Railway and Ship Propulsion

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The Italian Navy committed in 2006 to the Department of Astronautics, Electrical, and Energy Engineering-University of Rome "Sapienza" a Research Program aimed to define an automated procedure for air-gap monitoring of onboard generators. An effective solution was needed to overcome the heavy shortcomings of usual manual measurement practices. This paper describes the research work which led to very reliable rotor eccentricity indicators, based on measurement of internal currents in armature windings with parallel connections. The new approach permits absolute on-line estimations of both static and dynamic rotor shaft misalignments. A fully operative demonstrative system has been developed in the Department's laboratory. A four pole 17kV A generator was used for experiments, with artificial eccentricities produced by an apposite mechanical flange. A virtual instrument was used for data acquisition and processing, so obtaining a real-time estimation of the actual shaft misalignment. Comparison of data obtained from simulations and tests prove the reliability of the proposed methodology.

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Section: Theoretical Evaluation Of Numerical/experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DIEM project's outcomes: An automated air-gap monitoring approach for Italian Navy's on-board low-voltage generators

Bruzzese

Mazzuca

2012

2012 Electrical Systems for Aircraft, Railway and Ship Propulsion

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“…SG faults can be grouped as stator/rotor electrical faults [1], [2], [5][6][7][8], mechanical unbalances (due to the unbalanced magnetic pull (UMP), to bearing bad positioning and wear, and to line faults) [3], [4], [9][10][11][12][13][14][15][16], and other faults (in cooling, ventilating, braking systems, etc.) [1], [2].…”

Section: A Relevant Literature On Sg Monitoringmentioning

confidence: 99%

“…[1], [2]. Many papers deal with electrical faults, and few ones refer of practical on line air-gap monitoring in power SGs [3], [4], [9], [15]. No technique is well established for on-line evaluation of SG rotor eccentricities (REs).…”

Section: A Relevant Literature On Sg Monitoringmentioning

confidence: 99%

On-line monitoring of mechanical unbalance/ misalignment troubles in ship alternators by direct measurement of split-phase currents

Bruzzese

Mazzuca

Torre

2013

2013 IEEE Electric Ship Technologies Symposium (ESTS)

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Synchronous generators (SGs) are vital ganglia of the ship. SGs supply survival/defense/attack systems, propulsion, etc., so deserving on-line monitoring. Rotor unbalances shorten bearing lifetime, with overheating and stator-rotor rubs. No technique is definitely established for on-line evaluation of rotor eccentricities (REs) in working SGs. Actual manual air gap checks are time-consuming, and require unit shut-down and dismounting. This paper shows a method based on measurement of split-phase currents in stator windings with parallel branches. A symmetrical component transformation reverts the split-phase currents in rotating space vectors. The (p±1)-order vectors provide an affordable estimation of REs in 2p-pole machines. Rogowski coils or current transformers can be installed in the terminal box, or on winding front-ends, for current measurement. A LabView virtual instrument (VI) was developedfor method application. This paper also describes some tests carried out on board an Italian Navy's ship for on-line monitoring of shaft misalignments in a loaded 2MVA SG. Loads on board ships are usually unbalanced and may change suddenly. However, it is shown that the load-related unbalance can be separated from the eccentricity-related unbalance in the split-phase currents. Good assessment of air gap percentage reduction in the tested 2MVA machine was finally obtained.

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“…Achievements obtained for SAGE mainly focus on the three-phase current or voltage change [3][4][5][6], the circulating current inside parallel branches (CCPB) and its corresponding diagnosis method [7][8][9], the unbalanced magnetic pull (UMP) calculation via FEM [10,11], the winding inductance variation based on improved winding function theory [12], and so forth.…”

Section: Introductionmentioning

confidence: 99%

Stator Vibration Characteristic Identification of Turbogenerator among Single and Composite Faults Composed of Static Air-Gap Eccentricity and Rotor Interturn Short Circuit

Deng

Peng

et al. 2016

Shock and Vibration

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This paper investigates the radial stator vibration characteristics of turbogenerator under the static air-gap eccentricity (SAGE) fault, the rotor interturn short circuit (RISC) fault, and the composite faults (CFs) composed of SAGE and RISC, respectively. Firstly, the impact of the faulty types on the magnetic flux density (MFD) is analyzed, based on which the detailed expressions of the magnetic pull per unit area (MPPUA) on the stator under different performing conditions are deduced. Then, numerical FEM simulations based on Ansoft and an experimental study are carried out, taking the SDF-9 type fault simulating generator as the study object. It is shown that SAGE will increase the stator vibration at 2f (f is the electrical frequency) which already exists even in normal condition, while RISC and CF will bring in stator vibrations at f, 2f, 3f, and 4f at the same time. The vibration amplitudes under CF are larger than those under RISC. As SAGE increases, the vibration amplitudes of each harmonic component under CF will all be increased, while the development of RISC will decrease the 2nd harmonic vibration but meanwhile increase the 4th harmonic vibration. The achievements of this paper are beneficial for fault identification and condition monitoring of the turbogenerator.

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Calculation of Unbalanced Magnetic Pull in a Salient-Pole Synchronous Generator Using Finite-Element Method and Measured Shaft Orbit

Cited by 56 publications

References 27 publications

DIEM project's outcomes: An automated air-gap monitoring approach for Italian Navy's on-board low-voltage generators

DIEM project's outcomes: An automated air-gap monitoring approach for Italian Navy's on-board low-voltage generators

On-line monitoring of mechanical unbalance/ misalignment troubles in ship alternators by direct measurement of split-phase currents

Stator Vibration Characteristic Identification of Turbogenerator among Single and Composite Faults Composed of Static Air-Gap Eccentricity and Rotor Interturn Short Circuit

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