This article is based on the 28th Annual Lecture of the IEE Power Division which was given by the authors in March 1990. It traces the history of a major co-operative research and development project involving a team of engineers from the industrial and academic worlds. It began in 1978 and has also involved the CEGB, Hydro-Quebec, Bonneville Power Administration and Hong Kong Electric. The space available permits no more than a flavour of the overall activity to be given, but more detail is available in an extensive and detailed review commissioned by the IEE.1