Some Characteristics of A-C Conductor Corona

Corona discharges from a-c conductors are characterized by marked polarity effects. The most pronounced electrical polarity effect is the sudden burst of negative corona current each cycle, which sets up high frequency oscillations that produce electromagnetic radiation throughout the radio frequency spectrum. Polished and smooth weathered cables produce such radiation only during negative half cycles; mutilated and contaminated conductors produce it during both positive and negative half cycles under some conditions. An experimental investigation of these effects is described in this paper.