Investigation of impact of DC component on breakdown characteristics for different electric fields under composite AC & DC voltage

The valve side of the converter in high-voltage direct current is subjected to mixed voltages such as composite AC & DC voltage. In this study, effects homogeneity electric field on breakdown voltage were investigated for different ±DC component amplitudes efficiency factor was calculated using mean and maximum strengths all them. Variation air examined under ratios ±DC. As one result occurs at positive half-wave despite −DC being applied due corona discharge pulses. This point named polarity change point. increases with decrease up non-uniform field. less uniform field, measured slightly higher than ratio increases, gradually approaches similar obtained +DC experiments.