‌A Fault Analysis of A 110 kV Power Cable Intermediate Joint

This This paper takes a 110 kV power cable fault trip and shutdown incident as the research object. By analyzing historical operation and maintenance data and disassembly inspection of the faulty joint, the root causes of the intermediate joint fault are systematically investigated. The study reveals that the fundamental cause of the accident is misalignment at the lapping interface of the stress cone. To determine the origin of this stress cone misalignment, construction and installation records were traced and analyzed, ruling out construction process defects. Subsequently, combined with geological survey data of the cable pathway, an abnormal displacement was identified in the pipe-jacking section crossing the river. Three-dimensional spatial coordinate comparison of the pipe-jacking tunnel, performed using gyroscopic positioning technology, confirmed an axial offset of the pipe-jacking structure. The sustained mechanical stress induced by this offset is transmitted through the cable body, ultimately causing displacement and deformation of the stress cone position, leading to the power cable failure. As a non-typical fault type, this case provides important technical reference for cable pathway selection and design, quality control of pipe-jacking construction, and monitoring during the operation and maintenance phase.