Modeling of Cavity Discharges under AC and DC Voltage — Part II: Opportunities of the Dipole-based PD Model

To explain the occurrence of partial discharges (PD) in gaseous cavities embedded in the bulk dielectric of HV equipment, as well as to analyze the associated PD transients, two fundamental approaches have been proposed in the past, which are commonly referred to as network-based and dipole-based PD model. The first one has been reviewed critically in Part I of this publication, while this Part II is addressed to the dipole-based PD model. This alternative approach, which was promoted by Pedersen in the 1980, is based on the fundamentals of the gas discharge physics and adopts the electromagnetic field theory to treat the electromagnetic transients, which are associated with the establishment of an electrical dipole as consequence of a cavity discharge. However, understanding this more sophisticated concept needs a deep knowledge of the electromagnetic field theory based on Maxwell's equations. Presumably, this may be the reason why the dipole-based PD model is rarely adopted in the relevant literature. However, introducing some simplifications, this approach becomes easy understandable and can simply be handled, as highlighted in this paper based on some chosen case studies of practical interest.