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Title: Development of novel techniques for the assessment of inter-laminar resistance in transformer and reactor cores
Author: Hamzeh Bahmani, Hamed
ISNI:       0000 0004 5359 8237
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2014
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The main aim of this project is to investigate the influence of the inter-laminar short circuit faults on the performance of magnetic cores and develop a non-destructive method to detect these kinds of defects. The eddy current path in magnetic laminations which is magnetised by time varying magnetic field was modelled by an equivalent resistor network to calculate and predict the eddy current power losses in magnetic laminations. The model was validated over a wide range of magnetisation conditions. Based on the developed model, the influence of a wide range of magnetising frequency and peak flux density on the magnetic properties of electrical steels was studied. An experimental-analytical technique was developed to separate magnetic loss components over a wide range of magnetisation. Two electrical steel laminations, Conventional Grain Oriented (CGO) and Non-Oriented (NO), were used in the experimental work of the relevant studies. 2-D FE based modelling was performed to simulate inter-laminar faults on stacks of laminations and visualise the distribution of eddy currents in the faulted laminations. The influence of inter-laminar faults on the eddy current power loss was experimentally investigated by introducing artificial short circuits of different configurations on stacks of Epstein size laminations of GO steel. A non-destructive test method was developed to detect inter-laminar fault between the laminations of the magnetic cores by means of Flux Injection Probe (FIP). A prototype model of a FIP was developed and its application to quality assessment of transformer core laminations was investigated. The research presented here can be utilised by electrical steel manufacturers and electrical machine designers to survey the effect of inter-laminar faults on the magnetic properties of magnetic cores and their quality assessment, to reduce the risk of core damage or machine failure caused by the inter-laminar faults.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering