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| 2. |
- Karlsson, Martin, et al.
(författare)
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Rotor Dynamic Analysis of an Eccentric Hydropower Generator With Damper Winding for Reactive Load
- 2007
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Ingår i: Journal of applied mechanics. - : ASME International. - 0021-8936 .- 1528-9036. ; 74:6, s. 1178-1186
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetry in the magnetic circuit, around the air gap circumference, in a hydroelectric generator will give rise to a unbalanced magnetic pull. In this paper a hydropower rotor system is modeled and the influence of electro-mechanical forces due to overexcitation is analyzed The active power has been kept constant and the rotor excitation has been changed in order to vary the output of reactive power The electromagnetic field is solved with the finite element method Two electromagnetic models are compared: one with and one without damper winding. The mechanical model of the generator consists of a four id disk connected to an elastic shaft su orted b two bearin s de rees of freedom ri pp y g g g with linear properties. It has been found that the unbalanced magnetic pull slightly increasesfor reactive loads resulting in a decrease of natural frequencies and an increase of unbalance response. When the damper winding is included, the magnetic pull will decrease compared to the model without damper winding, and the pull force has two components: one radial and one tangential. The tangential component can influence the stability of the mechanical system for a range of design parameters.
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| 3. |
- Karlsson, Martin, et al.
(författare)
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Rotor dynamical analysis of a hydroelectric generator for active power
- 2006
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Ingår i: Proceedings. - Singapore : Aqua-Media International.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Asymmetry of the magnetic field in a synchronous generator will induce a magnetic unbalance pull. In this paper, a hydropower rotor system is modelled and the influence of electro-mechanical forces due to different amounts of real power is analysed. The electromagnetic field is solved with the finite element method and coupled with mechanical system as a magnetic stiffness. The mechanical model of the generator consists of a four degree of freedom rigid disc connected to an elastic shaft supported by two bearings with linear properties. It has been found that the unbalance magnetic pull increases for a lover amount of real power leading to a decrease of natural frequencies and an increase of unbalance response. Since many hydropower units are used for both part and full load it becomes important to model the electro-mechanical interaction when developing new generators, in order to improve the mechanical design.
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| 4. |
- Perers, Richard, et al.
(författare)
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Development of synchronous generators for Swedish hydropower : A review
- 2007
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier BV. - 1364-0321 .- 1879-0690. ; 11:5, s. 1008-1017
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Forskningsöversikt (refereegranskat)abstract
- The development of large-scale hydropower in Sweden started around 1900 when the Swedish government considered replacing of steam engine power with power from water falls, especially for utilization in railway operation. The hydropower development extends more than hundred years. Most of the Swedish hydropower was built in 1950s and 1960s. Due to the advancing age of installations, Sweden is facing an extensive refurbishment work in the upcoming decades. A large variety of individual designs exist among hydroelectric generators. The generator design has constantly strived for more compact and cost-effective constructions and this has resulted in a constant increase in the unit size. This paper describes the evolution of hydropower generators in Sweden. The development of assembling, stator insulation, cooling and materials used are described.
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| 5. |
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| 6. |
- Perers, Richard, et al.
(författare)
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Saturation Effects on Unbalanced Magnetic Pull in a Hydroelectric Generator With an Eccentric Rotor
- 2007
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Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 43:10, s. 3884-3890
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Tidskriftsartikel (refereegranskat)abstract
- We report an investigation of saturation effects on the unbalanced magnetic pull in a hydroelectric generator with 20% static eccen-tricity. We determine the magnetic pull force by the finite-element method in parallel with a simple analytical model for various no-loadvoltages and loads. Saturation significantly affects the magnitude of the unbalanced magnetic pull for high voltages and large loads.
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| 7. |
- Ranlöf, Martin, et al.
(författare)
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On Permeance Modeling of Large Hydrogenerators With Application to Voltage Harmonics Prediction
- 2010
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Ingår i: IEEE transactions on energy conversion. - 0885-8969 .- 1558-0059. ; 25:4, s. 1179-1186
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a permeance model that can be employed to estimate the no-load damper current loss and voltage waveform harmonics in large hydrogenerators is presented. The importance of modeling the damper magnetomotive force and inductances correctly is emphasized, and detailed descriptions are presented. The computed harmonics are compared with values obtained from time-stepped finite-element calculations and measured data. The results are in good agreement. The influence of pole-to-pole damper bar connections, and of the number of damper bars on the voltage waveform, is explained.
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