Vertical hydraulic generators experience with dynamic air gap monitoring

Pollock, G. B.; Lyles, J.F.

doi:10.1109/60.182648

Cited by 41 publications

(12 citation statements)

References 3 publications

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“…The repair cost was approximately equivalent to 50 % of a complete new generator. Apart from that, a two-year revenue loss of the unit was also incurred [34]. Therefore, from the view of safety operation and economic benefit, much more effort should be concentrated on the influence of excitation current in dynamic response of system for unit.…”

Section: The Effect Of Excitation Current On Bending Vibration Of Systemmentioning

confidence: 98%

Vibration analysis of coupled bending-torsional rotor-bearing system for hydraulic generating set with rub-impact under electromagnetic excitation

Zhang

et al. 2016

Arch Appl Mech

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Based on Jeffcott rotor model, the coupled bending-torsional rotor-bearing system with rub-impact under electromagnetic excitation for hydraulic generating set is established and the corresponding equation is given. The influence of excitation current, mass eccentricity and electromagnetic torque in the system is investigated by taking use of numerical method. The simulation results show that eccentricity is the crucial factor causing the changes of system dynamic characteristics, compared to the effect of torsional degree of freedom. And the larger the eccentricity is, the more obviously it affects the system responses. While the complicated dynamic behavior of bending vibration response can be restrained, due to the introduction of torsion motion, which has the property to suppress complex dynamic response of system, particularly, the inhibited and improved effect is more evident, as the eccentricity turns to be smaller. In addition, the unstable jumping phenomena of torsional response can be motivated by electromagnetic torque, which has to be taken seriously during the process of model establishment and dynamic analysis of system. From the global view of electromechanical coupling characteristics, the coupled bending-torsional vibration model with rub-impact under electromagnetic excitation can supply a more comprehensive reflection about the dynamic characteristics of system and provide useful reference with system state recognition and fault diagnosis.

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Section: The Effect Of Excitation Current On Bending Vibration Of Systemmentioning

confidence: 98%

Vibration analysis of coupled bending-torsional rotor-bearing system for hydraulic generating set with rub-impact under electromagnetic excitation

Zhang

et al. 2016

Arch Appl Mech

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“…[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%

“…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%

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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“…The early indication of rotor body faults can be seen from vibration monitoring and air-gap flux monitoring [1], [30], [31].…”

Section: ) Stator-winding Faultsmentioning

confidence: 99%

Condition monitoring techniques for electrical equipment-a literature survey

Han

Song

2003

IEEE Trans. Power Delivery

309

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Increasing interest has been seen in condition monitoring (CM) techniques for electrical equipment, mainly including transformer, generator, and induction motor in power plants, because CM has the potential to reduce operating costs, enhance the reliability of operation, and improve power supply and service to customers. Literatures are accumulated on developing intelligent CM systems with advanced practicability, sensitivity, reliability and automation. A literature survey is felt necessary with an aim to reflect the state of the art development in this important area. After introducing the concepts and functions of CM, this paper describes the popular monitoring methods for and research status of CM on transformer, generator, and induction motor, respectively. The paper also points out the potential benefits through the utilization of advanced signal processing and artificial intelligence techniques in developing novel CM schemes.

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Vertical hydraulic generators experience with dynamic air gap monitoring

Cited by 41 publications

References 3 publications

Vibration analysis of coupled bending-torsional rotor-bearing system for hydraulic generating set with rub-impact under electromagnetic excitation

Vibration analysis of coupled bending-torsional rotor-bearing system for hydraulic generating set with rub-impact under electromagnetic excitation

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

Condition monitoring techniques for electrical equipment-a literature survey

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