Breakdown of a Coaxial-Cylinder Gap in SF6 Under Switching Impulse Voltages

An experimental investigation into the impulse voltage strength of a coaxial-cylinder gap in SF6 is discussed. Impulse voltage waves of both polarities and different fronts were applied at the gap at different pressures. In each case the fifty percent breakdown voltage was determined and plotted according to the pressure for a given wave front and according to the wave front at a given pressure. An approach of the breakdown mechanisms is then developped to explain the trend of the obtained curves.