Pressure effects on breakdown in transformer oil ITO 100

Abstract

The measurements of dc breakdown voltage on the pressure were made in transformer oil ITO 100 for various electrode distances. It is commonly consider that slow increase of voltage, polarization and charging cause creation of small channels. The local heating of the liquid, high electric field, Towsend mechanism of ionization together with molecular ionization have result in generation of pre-breakdown bubbles. Small channels and bubbles are spaces with lower density as surrounded oil, where streamers can be created. Development of streamer and its connection of electrodes cause in breakdown in transformer oil. The processes influenced on the bubble and channels as volume compression, expansion or deformation are accompanied with the electric strength of transformer oil. Quantitative confirmation of this experimental fact is that the pressure significantly influences on the electric strength of studied liquid. The bubble theory is also used to explain the development of initial stages and breakdown in transformer oil.