Abstract: This paper investigates the physical processes of electrical breakdown in liquid dielectrics using transformer oil as a primary example. A comprehensive analysis of breakdown mechanisms is conducted, including impact ionization in liquids, the bubble mechanism, and the influence of emulsified moisture and solid conductive inclusions on the insulating properties of the oil. Primary attention is devoted to the experimental study of pre-breakdown processes at the “bubble-liquid” phase interface. Using an upgraded optical registration system with high spatial and temporal resolution, shadow images of streamer development initiated by gas inclusions were obtained. The study established that the process of streamer formation in oil is characterized by distinct stages. Successive development phases were identified: partial discharge within the bubble, charge injection into the liquid, and the decay of the streamer channel due to field screening by the accumulated space charge. It is shown that the cyclic “growth-decay” dynamics are determined by the rate of rise of the applied voltage and the conditions of electric field relaxation. The results refine existing concepts of breakdown dynamics in technical dielectrics and can be utilized to improve diagnostic methods and the design of insulation systems for high-voltage electrical equipment.

Cite: Korobeynikov S. , Shevchenko V. , Ridel A. , Vedernikov D. , Karpov D. , Savenko R.
On the Mechanisms of Breakdown in Liquid Dielectrics
In compilation 2025 IEEE 26th International Conference of Young Professionals in Electron Devices and Materials (EDM 2025). – Curran Associates, Inc.., 2026. – Т.2. – C.1-6. – ISBN 9781665477383. DOI: 10.1109/edm69524.2026.11631917 OpenAlex

Identifiers:

≡ OpenAlex:

W7202267138

Altmetrics: