Initiation of breakdown in strings of bubbles immersed in transformer oil: Paschen curves and proximity of bubbles

摘要

Recent experiments have shown that bubbling the transformer oil with air or sulfur hexafluoride leads to the decrease of breakdown voltage by 34% and 19%, respectively. To lend an insight to how streamers are initiated in an isolated bubble or strings of bubbles filled with air or SF and immersed in transformer oil, we computationally investigated the role of randomly distributed initial seeds of electrons inside bubbles of various size.