الفهرس 
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Abstract
This theSIs presents the results of an extensive experimental
investigation imoeffect of co-field enforced liquid motion on the breakdown voltage/gap iength characteristics of transformer
oil under highly non uniform field. To the author best knowledge this is the first time that such an investigation has been carried out under carefully controlled conditions. Previous work on the effect of enforced motion on the breakdown strength of liquids is very limited and confined to cross-field motion. In the present work direct voltages and a point -to-plane electrode geometry were used. Both the point and the plane electrodes were specially designed for the co-field flow experiments. The plane electrode was either solid or fitted with a 0.16 mm mesh or a 0.5 mm mesh
with provision for drainage. Tests for both polarities of the point were carried out on de gassed oil, oil saturated with oxygen, oil saturated with sulphur hexafluoride and oil containing 1¬methylnathalene as an additive. The additive was used in both degassed and oxygen-saturated oil. The velocity of the axial flow varied from 0 (stationary oil) to 280 cm/sec. and the gap length from 100 to 700 Il m. Each breakdown POlfit reported has been obtained using new electrodes and a fresh liquid sample. The results presented In this thesis have been obtained from 628 experimen ts.
For degassed oil there was a, marked Increase lfi the breakdown voltage
with .lficreasmg flow velocity for both
polarities of the point and over the whole range of gaps examined .