Research note: Sheath fault characteristics and modelling on underground power transmission cables

The paper reports on the experimental characterisation and subsequent development of an electrical model for cable oversheath faults under AC voltages. The characteristics can be represented by a combination of linear resistance and capacitance below a threshold voltage and a non-linear resistance above the threshold voltage. The proposed model was then incorporated into ATP (Alternative Transient Program). The simulation results clearly show satisfactory similarity between the model and the experimental results. The developed electrical model may therefore be used to accurately simulate sheath-to-earth fault conditions in buried cable systems.