Effects of conductor temperature on corona inception

Due to constraints in transmission capacity, High Voltage (HV) transmission lines are increasingly operated at maximum power levels. Increased power transmission for a given line gives rise to increased operating temperature. This paper describes the results of an experimental investigation into the effects of conductor temperature on corona inception and intensity. The experimental arrangement used consists of an inverted corona cage and a six stranded conductor. The cage is insulated and energised while the conductor is kept at a ground potential. This allows the conductor to be heated by the ohmic losses of a high operating current. Voltage measurements on the conductor, at 15kV intervals between 50kV and 110kV at varying temperatures ranging from 60°C to 120°C in 10°C increments, reveal that there is an observable, definitive increase in corona as the temperature increases.