Comparative Analysis of Optical Emission Spectra Emitted by Electrical Discharges in Insulating Liquids Under Direct and Alternating Voltage

Electrical discharges in insulating liquids are undesirable phenomena that significantly affect the reliability and lifespan of high-voltage power equipment. Understanding the mechanisms underlying these phenomena is essential for improving diagnostic methods and designing insulation systems. This study involves a comparative analysis of optical emission spectra emitted during electrical discharges in insulating liquids under direct and alternating voltage conditions. These fundamental investigations aim to understand the mechanisms of optical radiation emission and to identify characteristic spectral signatures that differ depending on the type of voltage applied. The experiments were conducted using selected insulating liquids and electrode systems capable of generating repeatable discharges under laboratory conditions. The spectra were recorded using a high-resolution spectrometer, analyzing a wide spectral range from ultraviolet to near-infrared. Special attention was paid to characteristic spectral lines and bands associated with excited atomic and molecular states in the discharge plasma. The results demonstrated that the type of voltage significantly influences the characteristics of the optical spectra, which is linked to differences in ionization, recombination mechanisms, and the interaction of the electric field with the insulating liquid. Observed differences in the intensity and position of spectral lines indicate distinct physicochemical processes accompanying discharges under direct and alternating voltage conditions. The obtained data can contribute to a better understanding of the physics of discharges in insulating liquids and provide a foundation for future work on developing advanced insulating materials and diagnostic methods in the power engineering field.