Life Prediction of Phosphor Bronze Reinforcing Tape Used in Underground Power Cables

Phosphor bronze tape is a key protection component of underground power transmission cables. During the service life, it is affected by both corrosion and fatigue effects, leading to the failure of material and eventually the failure of cables. In the present work, the combined effect on the cable failure is studied in five stages: pit initiation, pitting corrosion control, pit-crack transfer, crack propagation control, and material failure. The cable time to failure is defined as the time needed for a corrosion pit on the tape surface to transfer into a crack resulting from a cyclic fatigue load condition. The pit-crack transfer is described statistically by a pitting corrosion to crack propagation transfer probability function. The result shows that a life prediction model can convey the long-term data of cables and can predict the years of failure. Subsequently, the life prediction model is extended and tested to include crack transfer probability function.