Simulation of transient field coupling into directional coupler sensors using a 3D FDTD algorithm in cylindrical coordinates

Summary form only given. We introduce a 3D FDTD algorithm in cylindrical coordinates, which allows the investigation of the propagation of transient fields in high voltage cables and the interaction of these fields with directional coupler partial discharge (PD) sensors. The directional coupler sensors are modeled as 3D objects, consisting of a sensor electrode and 50 Ohm cables attached to this electrode for the signal output. The high voltage XLPE-insulated cable has an interface between the conductors and the electrical insulation, which is made of relatively thin semiconducting layers with extremely high permittivity, which is in range of 20 to 20000 for frequencies from 0.1 to 1000 MHz. These layers are represented by Debye media, the parameters of which are extracted from measurement data. A combination of the piecewise linear recursive convolution method (applied for dispersive components of the cable system) with the uniform FDTD algorithm gives an efficient and flexible tool for investigation of field propagation in XLPE cables