The influence of d-dot probes on the propagation of a guided surface discharge

The influence of the magnitude of an impulsive voltage on the propagation of a guided surface discharge is well known, as is the miluence of the magnitude and polarity of surface charge. In this study it has been observed that the propagation of the discharge is retarded by the presence of DDot probes inserted into the underlying guide electrode that act as the conductor return. This is observed as a reduction in the discharge current at the time when the discharge head is in the proximity of the probes. The effect is observed for all impulse voltages investigated and for both polarity combinations of initiating impulse voltage and surface charge. The duration of the initiating pulse is such that it is only present for the initial period of the discharge propagation and consequently thereafter the energy to drive the discharge is provided by charge stored on the insulator surface. It is therefore concluded that the observed effect is associated with charge distribution in the neighbourhood of the probe.