Direct Introduction of Semicon Layers in XLPE Cable Model

Detection and location of any partial discharge signal requires an accurate frequency dependent cable model to correctly simulate the P.D. signal attenuation during its propagation in the cable. This model should be capable of simulating the semiconducting layers which have significant effects on P.D. signal attenuation and its propagation velocity. There is a substantial need for improvements in the flexibility of transient cable model through direct introduction of the two semiconducting layers in the cable model. This can be employed, in the next step to develop a 3 phase cable model for ATP. This paper has derived an impedance formula for the semiconducting layers. The propagation characteristics of the PD signal in a cable having two semiconducting layers are evaluated by applying the derived formula, and are compared with the related characteristics in a cable with no semiconducting layer. The propagation of a PD signal applied to the sending end of the core conductor is investigated. In application of the semiconducting pick-up sensor in the cable joint, there would be a considerable high frequency voltage across each semiconducting layers which can be used for study of PD phenomenon.