Abstract: Single core cables have the characteristics of small outer diameter and light weight, and the design length of single core cables is not affected by cable reels and gravity. Currently, they are increasingly used in petrochemical enterprises. However, the longer the length of a single core cable, the higher the probability of insulation damage to the sheath layer, which can cause a sharp increase in shielding layer circulation and lead to safety accidents. Petrochemical companies have high requirements for continuous operation, and such cable accidents can result in huge economic losses when closed for repairs. Based on this, this article comprehensively studies the structural characteristics of single core cables, the calculation of shielding layer voltage considering harmonic effects, the comparison and optimization of grounding methods in different scenarios, the analysis of typical cable accident causes in petrochemical enterprises, and the full cycle online management of single core cable shielding layer data. Through the application of an online real-time monitoring system, a certain petrochemical 35 kV cable network can monitor the operation status of the shielding layer of single core cables in real time after deployment, successfully warning of 10 abnormal circulation caused by moisture in the grounding box, and carrying out timely maintenance and rectification to avoid main insulation breakdown accidents. This research result can greatly reduce the accident rate of single core cable operation in petrochemical enterprises, new energy stations, and urban underground pipe galleries. The application prospects of the online full cycle monitoring system for shielding layer data are broad.