Current-Voltage Characteristics of DC Corona in Hybrid Transmission Lines as Influenced by the Applied AC Voltage

Abstract

The objective of this paper is to calculate the current-voltage (I-V) characteristics and the onset voltage of corona on the DC conductor in a hybrid transmission line. The charge simulation method is applied for evaluating the electric field anywhere around the conductors of the hybrid line and for tracing the field lines emanating from the DC conductor. The onset voltage of corona on the DC conductor is calculated based on the condition of self-sustenance of discharge on the DC conductor. For an applied voltage above the corona onset-voltage, the DC corona-current is calculated by solving Poisson's equation along with the current-density and its continuity equations through an iterative procedure conducted over the field lines emanating from the DC conductor. The agreement between the calculated and measured onset-voltage and I-V characteristic of corona on the DC conductor is reasonable. The onset voltage of corona on the DC conductor decreases with the presence of the AC conductor. The DC corona current increases with the increase of the applied AC voltage for any value of the applied DC voltage.