Implications from the influence of electrohydrodynamic motion on breakdown with respect to the discharge mechanism in dielectric liquids

Abstract

Electrical discharge measurements with constant voltage pulses in a thin dielectric liquid layer between plane-parallel electrodes provide information about the dielectric strength as a statistical distribution of the time lags to breakdown. Under a large variety of circumstances, the time-lag distributions are composed of two main parts, termed the fast and the normal components. The nature of these components has been identified. The initial fast component lasts as long as the electrical charges, present or created in the liquid, have not yet been able to induce electrohydrodynamic motion. When the point of instability is reached, the probability of breakdown drops by a large amount as evidenced by the normal component of the time-lag distribution. The ions in the liquid, which are responsible for the electrohydrodynamic instability, also condition the electric-field distribution. The peak value of the local field strength is likely to determine the breakdown characteristics.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>