Self electrical breakdown in biodegradable oil

The fundamental breakdown physics of biodegradable oil is investigated with high speed electrical and optical diagnostics with temporal resolution down to several 100ps. The set up employs a cable discharge into a coaxial system with axial discharge and load line to simulate a matched terminating impedance. A unique feed-through design creates no discontinuities in the system lines through the discharge chamber. The impedance of the system is matched at 50 ohms including a novel design for impedance matching transitions from discharge cable to coaxial system to load line allowing for a sub-nanosecond response. This paper presents results on self breakdown with voltages of up to 60 kV. Self breakdown is achieved by charging the discharge cable and load line to +/-30 kV respectively. Transmission line type current sensors and a capacitive voltage divider with fast amplifiers/attenuators are used in order to obtain a complete range of information from amplitudes of 0.1 mA to 1kA with temporal resolutions of 300 ps. Optical measurements include high speed photography and shadowgraphy. Detailed optical diagnostics along with high speed electrical diagnostics will address the mechanism initiating/assisting biodegradable oil volume breakdown.