Recent trends in turbogenerators

Abstract

The paper begins with an historical account of the evolution of the turbogenerator, emphasing the landmarks in its development. Against the background of probable future requirements, a critical assessment is made of current design philosophies and their limitations are examined. The barriers to advancement in technology, in materials, and in physical size and weight are identified and the resulting trends in design investigated. The interdependence of generator and transmission-system characteristics is considered in relation to likely advances in generator design. The problem areas of stator core and winding vibration and core-end heating are reviewed. Developments in structural materials, cooling systems, insulation and handling and transport are covered. Recent developments in excitation systems, notably in the `brushless? concept, that have obviated the need for sliprings are also examined. The final section includes a review of the potential advantages and practical problems associated with the possible use of design principles involving increasingly radical departures from current established practice. These progress from the completely liquid-cooled machine without hydrogen, prototypes of which have already been manufactured, through the more or less conventional generator but with stator and rotor windings accommodated in the airgap, to designs using evaporative and cryogenic cooling principles. An extensive bibliography is included.