PD detection and localisation in cross-bonded HV cable systems

A great deal of research work on PD based cable insulation monitoring, diagnostics and localisation has been published in recent years on medium voltage (MV) cables. The work to be reported on extends PD detection and localisation into cross-bonded HV cable systems. The main challenge in PD monitoring of cross bonded HV cables lies in the interconnectedness of sheaths of the three phases, making it difficult to localise which of the three phases a PD signal has emanated from. A second challenge is the use of coaxial cables for connecting cable sheaths to cable link box for ease of installation and protection against moisture. The proposed paper addresses PD detection and localisation in cross-bonded HV cables. It presents experimental investigations into PD pulse coupling between the centre conductor and the cable sheath and the behaviour of PD pulse propagation in cross-bonded HV cables. It also proposes a model to describe the coupling effect in cross-bonding (CB) cable system for PD monitoring and localisation and demonstrates the effectiveness of the application of the model.