Salman Minhas | University of the Witwatersrand (original) (raw)
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Papers by Salman Minhas
The work presented in this thesis contributes to the understanding of the dynamic behaviour of la... more The work presented in this thesis contributes to the understanding of the dynamic behaviour of large power transformer windings under short circuit forces. A simple yet accurate method of prediction of electromagnetic forces is developed and used as input to the dynamic mechanical model. In developing this model the mechanical properties of oil-impregnated pressboard have been investigated and measured in a specially designed rig which simulates the typical power transformer environment. Assumptions have been made regarding these properties to enable them to be meaningfully incorporated in a dynamic model of a transformer. Predictions made using the model have been compared with actual measurements on a transformer and a correlation within 20%-30% was achieved. The work demonstrated the importance of mechanical prestress to ensure that no serious nonlinearities will be encountered in the mechanical behaviour when short-circuit forces are present in a power transformer. It was also f...
The work presented in this thesis contributes to the understanding of the dynamic behaviour of la... more The work presented in this thesis contributes to the understanding of the dynamic behaviour of large power transformer windings under short circuit forces. A simple yet accurate method of prediction of electromagnetic forces is developed and used as input to the dynamic mechanical model. In developing this model the mechanical properties of oil-impregnated pressboard have been investigated and measured in a specially designed rig which simulates the typical power transformer environment. Assumptions have been made regarding these properties to enable them to be meaningfully incorporated in a dynamic model of a transformer. Predictions made using the model have been compared with actual measurements on a transformer and a correlation within 20%-30% was achieved. The work demonstrated the importance of mechanical prestress to ensure that no serious nonlinearities will be encountered in the mechanical behaviour when short-circuit forces are present in a power transformer. It was also f...