Analysis and detection of shorted turns in the field winding of cylindrical rotor synchronous machines
Analysis and detection of shorted turns in the field winding of cylindrical rotor synchronous machines
Due to the continuous use of large generators in industry and in power stations, and the need to keep such machines running reliably, the detection of shorted field winding turns in synchronous machines is of increasing importance. The most serious outcome of a deteriorating fault condition is increased vibration, and on-line monitoring to detect rotor winding (and other) faults in the largest machines is now a strong possibility, and certainly periodic monitoring of all large machines in strategic situations. The principal aim of this thesis is to devise a two-dimensional analytical model to detect the appearance of a rotor short-circuit, the field coil concerned and the number of turns involved. To achieve this objective, the analytical and experimental technique considered is to use two matched diagonally opposite air-gap search coils connected in a way that exposes the `difference' field of the fault. The predicted results are verified by open-circuit measurements on a small four-pole model machine in which known rotor faults can be established. Throughout this thesis, some other faults which occur in the machine, possibly wholely or partly due to the presence of a rotor short-circuit itself, are considered in detail; such faults as unbalanced magnetic pull(ump), static and dynamic eccentricity. In order to take full account of the nonlinearity, caused by saturation and the presence of slotting, a two-dimensional analysis using linear traingular finite elements is also presented. Computations were performed under no-load and load conditions. (D81697)
University of Southampton
1987
Hennache, Ali
(1987)
Analysis and detection of shorted turns in the field winding of cylindrical rotor synchronous machines.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Due to the continuous use of large generators in industry and in power stations, and the need to keep such machines running reliably, the detection of shorted field winding turns in synchronous machines is of increasing importance. The most serious outcome of a deteriorating fault condition is increased vibration, and on-line monitoring to detect rotor winding (and other) faults in the largest machines is now a strong possibility, and certainly periodic monitoring of all large machines in strategic situations. The principal aim of this thesis is to devise a two-dimensional analytical model to detect the appearance of a rotor short-circuit, the field coil concerned and the number of turns involved. To achieve this objective, the analytical and experimental technique considered is to use two matched diagonally opposite air-gap search coils connected in a way that exposes the `difference' field of the fault. The predicted results are verified by open-circuit measurements on a small four-pole model machine in which known rotor faults can be established. Throughout this thesis, some other faults which occur in the machine, possibly wholely or partly due to the presence of a rotor short-circuit itself, are considered in detail; such faults as unbalanced magnetic pull(ump), static and dynamic eccentricity. In order to take full account of the nonlinearity, caused by saturation and the presence of slotting, a two-dimensional analysis using linear traingular finite elements is also presented. Computations were performed under no-load and load conditions. (D81697)
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Published date: 1987
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Local EPrints ID: 461760
URI: http://eprints.soton.ac.uk/id/eprint/461760
PURE UUID: d485928f-9fb1-4c97-9b6a-c14cfb5c6f13
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Date deposited: 04 Jul 2022 18:54
Last modified: 04 Jul 2022 18:54
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Author:
Ali Hennache
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