Research on Cable Head Monitoring Technology for Transmission Lines

Abstract

Buried cables are located in harsh environments with high corrosion, uneven soil acidity and alkalinity, and groundwater immersion, resulting in complex structures. Especially for long-distance 10 kV transmission cables, the path planning is relatively long and cannot be connected at once, requiring a connection at the middle end of the cable. The production of cable joints is generally carried out in the foundation pit or well, with complex processes and manual production throughout the entire process, which cannot avoid manual technical deviations. Therefore, cable line faults mostly occur in the intermediate joints. Due to the uneven distribution of the temperature field caused by the accumulation of the electric field, the heat is transferred outward from the peeling chamfer point, resulting in uneven heating. In addition to the skin effect and proximity effect of current, the accumulation of electric field at the chamfer process point of the main insulation and outer semiconducting layer is intensified, and then the insulation is gradually broken down, causing a short circuit or ground fault. This article first studies the temperature and electric field distribution at the cable joint, and considers installing a small temperature sensor at the middle joint of the cable. The sensor is powered by a small electromagnetic energy coil, which can monitor abnormal temperature and electric field changes at the joint in real-time.