Observation and Analysis of Gas Temperature Characteristic in the Streamer-to-Leader Transition under Positive Impulse Discharge

The discharge mechanisms in air gap discharge are very important to the research of arc caused by earth fault. The gas temperature characteristic in a long air gap is observed by a Schlieren system in this paoer. The gas temperature characteristics of the streamer-to-leader transition process in long air gap are obtained and the radial temperature of the stem is approximately Gauss distribution. After that, the Gallimberti thermodynamic mechanism model is modified, where the influence of the current density distribution was introduced to the calculation. At last, the effectiveness of the modified model is proved by the experiment results.