A Review of Results From Thermal Cycling Tests of Hydrogenerator Stator Windings

Istad, Maren Kristine; Runde, M.; Nysveen, Arne

doi:10.1109/tec.2011.2127479

Cited by 38 publications

(24 citation statements)

References 38 publications

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“…There are many magnetic poles of the Three Gorges hydro-generator, and the rotor magnetic pole structure is relatively complex. Limited by the calculation capacity of the simulation equipment, in order to ensure the accurate calculation of magnetic pole thermal stress, it is necessary to reasonably simplify the rotor solution domain and establish the calculation model of a single magnetic pole, shown in Figure 1, where the assumptions are as follows [18][19][20][21][22]. (1) The calculation model for one magnetic pole of the hydro-generator is established given that all rotor magnetic poles and wind paths of the hydro-generator are symmetrical.…”

Section: Physical Modelmentioning

confidence: 99%

Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Wang

2019

Energies

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Rotor winding inter-turn short circuit a common fault in hydro-generators. This fault would change the temperature, stress, and other thermal fields of a rotor and threaten the safe operation of the generator. In this paper, the Three Gorges hydro-generator is taken as an example. Mathematical models of three-dimensional temperature field and thermal stress field of rotor magnetic poles are established based on heat transfer theory and solved by finite element method. The temperature field, thermal deformation, and thermal stress distribution of magnetic poles in rotor winding inter-turn short circuit are calculated. On the basis of the calculation, the effects of the different turn numbers and positions of short circuit on the temperature, thermal deformation, and thermal stress of rotor magnetic poles are further studied. It is concluded that the thermal stress of the winding adjacent to the shorted turn would decrease, the thermal stress of the winding farther away from the shorted winding would increase, and so on. The results of this paper can provide references for inter-turn short circuit fault diagnosis and lay a foundation for the further studies of related faults.

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Section: Physical Modelmentioning

confidence: 99%

Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Wang

2019

Energies

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“…These multiple stresses cause insulation aging. Previous research has shown that the invalidation of stator insulation in the aging progress is the root cause for large generator breakdown [ 4 , 5 ]. Implementing condition monitoring (CM) technology on stator insulation holds the promise of enhancing the safety and economic operation of a large generator.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the merits of Lamb wave on SHM of composite, the Lamb wave tomography method shows a potential solution for intuitively detecting stator insulation damages [ 20 ]. However, the stator insulation of large generators is mostly composed of mica tapes and epoxy resins, which can be regarded as composite materials with bar-like structures [ 4 ]. Different from other homogenous and isotropic structures, Lamb waves propagate more complexly on stator insulation.…”

Section: Introductionmentioning

confidence: 99%

Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves

2018

Sensors

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Large generators are the principal pieces of equipment in power systems, and their operation reliability critically depends on the stator insulation. Damages in stator insulation will gradually lead to the failure and breakdown of generator. Due to the advantages of Lamb waves in Structural health monitoring (SHM), in this study, a distributed piezoelectric (PZT) sensor system and hybrid features of the Lamb waves are introduced to identify stator insulation damage of large generator. A hierarchical probability damage-imaging (PDI) algorithm is proposed to tackle the material inhomogeneity and anisotropy of the stator insulation. The proposed method includes three steps: global detection using correlation coefficients, local detection using Time of flight (ToF) along with the amplitude of damage-scattered Lamb wave, and final images fusion. Wavelet Transform was used to extract the ToF of Lamb wave in terms of the time-frequency domain. Finite Element Modeling (FEM) simulation and experimental work were carried out to identify four typical stator insulation damages for validation, including inner void, inner delamination, puncture, and crack. Results show that the proposed method can precisely identify the location of stator insulation damage, and the reconstruction image can be used to identify the size of stator insulation damage.

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“…Under the influence of electric, thermal, vibration and mechanical stresses, the stator and rotor main insulation of the generator may be caused serious faults such as aging, shelling and discharging. Many specialists make researches about generator insulation failure mechanism, discharging and fault monitoring after insulation aging [1][2][3][4][5][6][7][8][9][10]. Dr. H. Zhu and C. Morton made a detailed research on the diagnosis about thermal aging of stator windings [11,12].…”

Section: Introductionmentioning

confidence: 99%

Research on Stator Main Insulation Temperature Field of Air-Cooled Turbo-Generator after Main Insulation Shelling

et al. 2018

Energies

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The stator main insulation is the key component of turbo-generator, which is related to the thermal aging of turbo-generator. It is vital to accurately judge the generator aging by calculating the temperature distribution under main insulation normal operation and fault operation. In this paper, taking a 150 MW air-cooled turbo-generator as an example, the temperature field of the main insulation was studied after the stator main insulation shelling. Based on the finite element method, the stator temperature field after the main insulation shelling was calculated. The main insulation position of maximum temperature drop and the temperature distribution of the stator main insulation along the circumference and the axial direction were analyzed. At the same time, with the shelling gap of main insulation increases, the temperature distribution between shelling gap δ = 0.5 mm and δ = 1.0 mm was compared. The results can provide a theory for fault monitoring and diagnostics of the large-scale turbine generator.

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A Review of Results From Thermal Cycling Tests of Hydrogenerator Stator Windings

Cited by 38 publications

References 38 publications

Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Calculation and Analysis of Rotor Thermal Static Field for Inter-Turn Short Circuit of Large Hydro-Generator Excitation Winding

Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves

Research on Stator Main Insulation Temperature Field of Air-Cooled Turbo-Generator after Main Insulation Shelling

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