Partial discharges and associated transients: the induced charge concept versus capacitive modeling

Ensuring a reliable electric service to industrial, commercial and residential customers is becoming an important parameter for every electricity company due to the increased demand from the customers for less downtime, high productivity and reduced maintenance cost of machinery caused by unscheduled frequent interruptions due to underground power cable failures. The presence of partial discharges (PD) is one of the most prominent indicators of defects and ongoing degradation processes of electrical insulation. The capacitive network representation of the void (model) has long been used for the study of the transients generated by a breakdown void. As an alternative to the capacitive representation of the void (model) the induced charge concept has been introduced expressing strong criticism against the capacitance modeling of voids. This paper discusses and argues this criticism and exploits the potential and weakness of the classical capacitive representation of the voids from a theoretical point of view. Finally, a new capacitive model for voids is proposed based on the induced charge concept.