Influence of Conductor Temperature on the Voltage–Current Characteristic of Corona Discharge in a Coaxial Arrangement—Experiments and Simulation

High-current-carrying capability with minimum thermal elongation is one of the key reasons for using high-temperature low-sag (HTLS) conductors in modern power systems. However, their higher operational temperature can significantly affect corona discharge characteristics. Corona is one of the key factors in transmission line design considerations. Corona discharge is the leading cause of audible noise, radio interference, and corona loss in power transmission systems. The influence of conductor temperature on corona discharge characteristics is investigated in this paper using experimental methods and computational simulations. A simulation framework has been developed in COMSOL Multiphysics using the physics of plasmas and electrostatics to simulate corona plasma dynamic behavior and electric field distribution. The results show that the conductor temperature enhances the ionization by electron impact, enhances the production of positive and negative ions, changes the electric field distribution, and increases the electron temperature. This analysis emphasizes that temperature-dependent conditions affect the inception and intensity of corona discharge. Additionally, an experimental model was developed to evaluate corona voltage–current characteristics under varying temperature conditions. The study presents both simulation results and a newly developed model for predicting corona current at high conductor temperatures.