Research on injection charge characteristics of long streamer under positive lightning impulse voltage

Streamer is the main process of air gap discharge, and the injection charge characteristics of a long streamer under positive impulse voltage are of great significance for revealing the discharge mechanism of long air gap, selecting reasonable air gap distance, optimizing insulation configuration, and solving the key problems faced by current transmission engineering. Taking the 1 m rod–plate gap as the research object, the long streamer with a length of 20–35 cm was obtained at the rod electrode head by applying positive lightning impulse voltage, and the total injection space charge with a different radius and length was obtained by measuring the streamer discharge current at the high voltage end and integrating it. The empirical formulas between the total injection charge and the initial voltage and the length of the streamer are deduced theoretically and verified by experimental data. The total injection charge has a linear relationship with the square of the initial voltage and the square of the streamer length. The key physical parameters such as the initial physical process of the streamer under impulse voltage, the minimum initial field strength of the streamer, and the internal electric field in the streamer region are also discussed. Research and discussions [Ebert and Sentman, J. Phys. D: Appl. Phys. 41, 230301 (2008)] were carried out.