Numerical modelling for investigation and optimization of a sensor for sensitive partial discharge detection on high-voltage XLPE cables

Based on experimental investigations a theoretical model of a sensor for partial discharge (PD) detection on high‐voltage cross‐linked polyethylene (XLPE)‐insulated cables respectively joints has been developed. The model handles radial symmetric sensors and is based on the Finite‐Difference Time‐Domain (FDTD) method in which a cylindrical coordinate system is exploited. The calculation provides field values at each node of the FDTD grid. The field pattern in the cable and sensor at different time steps is used to investigate the coupling mechanism of the sensor. It is also used for parametric studies of the sensor, e. g. the dependence of the sensitivity on geometrical characteristics of the sensor, which is investigated theoretically as well as experimentally. Results of computer simulation are in a good agreement with experimental data derived for such sensors.