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As converter stations are increasingly constructed at high altitudes, how to reasonably select the minimum air spacing of converter station substation equipment has become an important issue for DC power transmission at high altitudes. In order to study the influence of air environment on switching impulse discharge characteristics of air gap at high altitudes, this paper conducts switching impulse discharge tests on 1 m rod-plate air gap under different air pressure, temperature, and humidity conditions, investigates switching impulse discharge characteristics of rod-plate air gap at high altitude, and compares and analyses differences in correction results of various discharge voltage correction methods. Studies have shown that air pressure, temperature, and humidity have an effect on air gap discharge voltage. Meanwhile, based on different atmospheric parameters, correction formulas are obtained for 1m rod-plate air gap discharge voltage, and the elevation correction coefficients of 1m rod-plate air gap at each altitude was obtained. The results of the study provide a reference for external insulation of equipment and its insulation fit in converter stations at high altitude.

The characteristics of atmospheric-pressure glow discharge (APGD) produced by rod-plate electrodes are experimentally determined. APGD is sustained by applying a high DC voltage between the electrodes. At atmospheric pressure, the shift from corona discharge to glow discharge is investigated. A rod-plate discharges configuration's volt–ampere properties show the existence of three discharge regimes: corona, glow, and spark. The variations in the electrical field distribution in the various regimes are mirrored in the discharge luminosity. The rod-plate patterns are created under a dark region, and are visible mainly due to the effect of electrons heated by the local enhanced electric field at the interface, according to the optical emission spectra of the entire discharge. [ABSTRACT FROM AUTHOR]