Calculation of power losses in the damper winding of large hydrogenerators at open-circuit and load conditions

Traxler-Samek, G.; Lugand, Thomas; Schwery, A.

doi:10.1109/icelmach.2008.4800068

Cited by 14 publications

(14 citation statements)

References 9 publications

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“…This is the same with the respective frequency oscillation of the electromagnetic torque [6]. Also, the peak value is relatively high on account of the very small resistance of the damper ring [7]. For example an induced voltage equal to 45 mV produces a current that is almost 450 A.…”

Section: Field Currentsmentioning

confidence: 61%

A performance analysis of a hydrogenerator in the case of field short-circuit using FEM

Dallas

Safacas²,

Kappatou

2011

REPQJ

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Abstract. The maintenance of synchronous generators is very significant for the energy production. Being aware of the performance of a synchronous machine during different kinds of faults, such as phase to phase, phase to ground or field shortcircuits, could provide useful information about their protection. A short-circuit in the field excitation is not a common fault, but it is severe enough to create high oscillations to both electrical and mechanical magnitudes (field, stator and damper currents, rotor shaft torque, load angle etc). Such kind of faults is difficult to examine and provide experimental results because of the kinds of generator used for energy production. The size of these machines, either hydrogenerator or turbogenerator, is enormous for experimental laboratory studies. Another important issue that arises is the difficulties in the accurate calculation of the damper currents during transient operation. The Finite Element Method analysis gives solution to this kind of problems, as it can calculate as well the damper, stator and field currents as the electromagnetic field distribution inside the air gap.

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Section: Field Currentsmentioning

confidence: 61%

A performance analysis of a hydrogenerator in the case of field short-circuit using FEM

Dallas

Safacas²,

Kappatou

2011

REPQJ

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“…The separate permeance functions in (2) can be expressed in the stator reference frame as: (5) [ ] (6) Λ sat , Λ Ssl , and Λ Dl are all dimensionless relative permeance functions that take the effects of saturation and slotting on the pole permeance function into account. Note that (6) assumes an integral slot stator winding and that (7) is valid also for machines with alternately displaced damper cages.…”

Section: B Permeance Functionsmentioning

confidence: 99%

“…By a proper inclusion of a set of damper circuit equations in the rotating field model, the ohmic damper losses during different operational conditions can also be addressed [5]. Recently, rotating field models have been extended to include the effects of skewing and inter-bar current paths via rotor iron on the damper circuit formulation [6]- [8].…”

Section: Introductionmentioning

confidence: 99%

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The rotating field method applied to damper loss calculation in large hydrogenerators

Ranlöf

Lundin

2010

The XIX International Conference on Electrical Machines - ICEM 2010

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In this paper, we discuss key aspects of analytical rotating field models that can be used to estimate the damper losses in large hydrogenerators during steady load conditions. Model features of particular importance, like the saturation permeance and the structure of the damper circuit are described in greater detail. Damper currents extracted from the analytic model are found to be in good agreement with currents obtained from coupled field-circuit 2-D finite element calculations. The applicability of the model for damper current prediction during steady unbalanced load conditions is also demonstrated.

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“…Some experts and scholars have made relevant researches on the eddy current losses of a synchronous generator, such as eddy current losses in damper bars [8][9][10], eddy current loss in the end region of a turbo generator, eddy current losses in the clamping plate and so on [11][12][13]. However, there are less studies on the asymmetric distribution of the eddy current in damper bars.…”

Section: Introductionmentioning

confidence: 99%

Eddy current density asymmetric distribution of damper bars in bulb tubular turbine generator

Qiu

Fan

et al. 2017

Archives of Electrical Engineering

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Abstract:The major reasons that cause the damage of damper bars in the leeward side are found in this paper. It provides a route for the structure optimization design of a hydro generator. Firstly, capacity of a 24 MW bulb tubular turbine generator is taken as an example in this paper. The transient electromagnetic field model is established, and the correctness of the model is verified by the comparison of experimental results and simulation data. Secondly, when the generator is operated at rated condition, the eddy current density distributions of damper bars are studied. And the asymmetric phenomenon of the eddy current density on damper bars is discovered. The change laws of the eddy currents in damper bars are determined through further analysis. Thirdly, through the study of eddy current distributions under different conditions, it is confirmed that the stator slots and armature reaction are the main factors to affect the asymmetric distribution of the eddy current in damper bars. Finally, the studies of the magnetic density distribution and theoretical analysis revealed the asymmetric distribution mechanism of eddy current density.

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Calculation of power losses in the damper winding of large hydrogenerators at open-circuit and load conditions

Cited by 14 publications

References 9 publications

A performance analysis of a hydrogenerator in the case of field short-circuit using FEM

A performance analysis of a hydrogenerator in the case of field short-circuit using FEM

The rotating field method applied to damper loss calculation in large hydrogenerators

Eddy current density asymmetric distribution of damper bars in bulb tubular turbine generator

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