About the influence of temperature and humidity level on pulse shape parameters of positive DC corona discharges in air

Abstract

The increasing importance of HVDC transmission systems requires the development and evaluation of suitable basic approaches regarding the partial discharge diagnosis. Although diverse promising approaches are identified, recent research is focused on standard atmospheric conditions. Due to the fact that this is just partly consistent to real operating conditions, additional research is required. Focusing on the time domain analysis of corona discharges, occurring under positive DC voltage stress in air, a measurement method for investigating the influence of varying atmospheric quantities is presented. Measurements are carried out for five different relative humidity levels in the range of 20 % to 95 % and for four different temperature levels in the range of 20 °C to 65 °C. As characterizing pulse shape parameters, the rise time, the pulse width and the fall time are determined as well as the apparent charge. The gained values are compared to each other and reconciled with physical processes.