Partial Discharge localization on cross-bonded cable systems

Abstract

When a Partial Discharge (PD) signal, which travels through a cross-bonded (CB) power cable system, reaches a CB joint, the signal not only continues its way on the defect phase but it also enters and propagates in the other faultless phases. For analyzing the effect of CB joints on PD signal propagation, an experimental model of CB cable systems is designed. The experimental setup uses 1km length of a PE insulated cable. The setup models one major section of real sectionalized CB high voltage three-phase cable systems. Transient signals are applied to the setup to model PD in different possible locations and the signals are detected in different locations. It is concluded how the faulty phase can be identified according to the results obtained from the CB and the non-CB joints. Single-phase PD measurements are also carried out, and the results are compared with those of PD in the CB cable system. It is suggested to use summation of the PD signals acquired from three high frequency current transformers installed on three screen conductors of three phases at each joint for PD localization and charge estimation. Finally, a monitoring algorithm is proposed for PD localization and defected phase identification.