Investigation of high electrical breakdown for pressurized water dielectric with microsecond charging

By means of a coaxial apparatus, a high electrical breakdown experiment for pressurized water dielectric with microsecond charging was carried out. The experimental results were presented and analyzed. The conclusions are as follows: (1) breakdown for water dielectric initiates at the positive electrode; (2) observed breakdown stress at constant pressure is in good agreement with Martin formula; (3) primary mechanism to improve electrical breakdown strength for pressurized water dielectric is that, bubbles on the surface of electrodes is compressed by pressurization and the number of the bubbles is reduced.