An experimental investigation into the repetitive breakdown and flashover properties of insulating tubes and films

Many pulsed power and high voltage systems incorporate coaxial oil insulated transmission lines capable of withstanding voltages in excess of 100 kV. The aim of this test programme was to investigate the material limits of solid dielectric insulation at such potentials. Although this can lead to catastrophic failure it can also result in an increased line capacitance and with the correct choice of dielectric it may be possible to operate with increased energy levels and reduced system volumes. This test programme addresses the electrical breakdown characteristics of various materials for pulses representative of those generated in a typical high voltage transmission line system. The broad aims of this test programme were to: compare the flashover and breakdown performance of different materials in air and in oil; compare the voltage characteristics of insulating tubes and insulating films for different materials; and investigate the effect of repetitive operation and pulse charging upon solid insulation