Light Emission from Tracking Discharges on Organic Insulation

This paper describes measured spectra of light emitted from discharges generated on the surface of organic insulations. The corona discharge before carbon deposit showed many ultraviolet lines below 400 nm. These spectra are produced by the energy transition of molecular nitrogen in air. After carbon deposit, the scintillation discharge initiates. It contains many lines in the visible light above 400 nm. The spectra of the scintillation discharge in the visible light do not correspond with those of the dominant molecular gases in air. Therefore, the molecular structure of the materials may influence the line spectra for the scintillation discharge. The scintillation discharge approaches toward the sample´s surface. The arc discharge showed many spectra in the ultraviolet and/or visible range. The arc discharge bridges between the electrodes, far away from the sample´s surface as compared with other discharges.