Investigation of PD signal propagation characteristics in XLPE cables

Online monitoring of HV XLPE cables is a major interest for utilities. Due to severe and rapid risk of life of this type of cable with occurrence of partial discharges, studies are carried out for detection and location of PD. However there is a lack of models that can help to accurately detect the partial discharge and its location in installed cables, due to the relatively long length and the load condition of cable. Detection and location of any partial discharge signal requires: A verified knowledge of phenomena which contributes to P.D. propagation and its deformation, measured data of P.D. type signal propagation on different cable test setups, accurate frequency dependent cable model to correctly simulate the P.D. signal attenuation in cable, a model capable of simulating the semiconducting layer which has significant effects on P.D. signal attenuation and its propagation velocity. This paper presents the results of examination and simulation of a 136 meters XLPE cable and a 45 meters XLPE cable of two different types. Proposes a preliminary method to reproduce the P.D. signal of its origin, based on the measurement results at the terminals.