Study on the Path and Thermal Characteristics of the Spark Discharge Between Ice and Electrode Gap

The corona-to-spark transition is a fundamental discharge process between the ice and electrode gap, the first step of a partial arc formation on the ice-covered insulators. This article set up a calibrated Schlieren system synchronized with electrical signals to study the primary process and characteristics of the corona-to-spark transition between ice and electrode gap. The Schlieren system is calibrated by a Plano lens and verified with a thermocouple; a series of experiments are set up to obtain the discharge process’s voltage, current, and temperature in the time domain. A vibration–translational model is proposed to quantitatively explain the influence of discharge path on the thermal–electrical characteristics. It is found that the brush discharge appears only in the air, which promotes the temperature rise during the corona-to-spark transition and makes the discharge’s air path have the highest temperature. The findings in this article will provide a basic understanding of the corona-to-spark transition characteristics between the electrode and ice gap.