A.C. testing at Project UHV yields useful corona data

Project UHV (ultra-high voltage) was initiated by the US Electric Research Council in 1967 to study overhead transmission lines with alternating voltages in excess of 1000 kV. Project UHV evolved from Project UHV, the research facility built and funded by General Electric (US) in the period from 1958 to 1964 to provide data for extra-high-voltage transmission in the 400¿750 kV range. In the first stage of the project, from 1967 to 1973, a single-phase test line was constructed and energised to define the problems and assess the study priorities. In 1973, Project UHV was transferred to the jurisdiction of the US Electric Power Research Institute (EPRI). A broad spectrum of subjects vital to the design of u.h.v. lines have been studied since. These include air-gap strength, Insulator contamination, switching surge flashover, field effects and corona. This article will discuss some of the results of the corona studies on the prototype transmission line