10 kV Novel Extended Cold-Shrinkable Cable Intermediate Joint Connection Device

In repair operation of distribution network cable faults, conventional treatment method requires cutting out the faulty section, which often results in insufficient cable connection length. The method typically requires installation of compensation cable segments to complete the repair. However, this method significantly increases the number of intermediate joints (each compensation segment requires two additional joints), thereby not only increasing economic costs but also introducing additional potential failure points due to joint proliferation, ultimately compromising long-term power system reliability. To address this technical challenge, an innovative fault repair method utilizing an extended cold-shrinkable cable intermediate joint connection device was proposed. The device comprised two core components: an extended cold-shrinkable cable intermediate joint body and a connecting copper rod, which could function synergistically to ensure highly reliable cable connections with superior electrical performance. The extended cold-shrinkable intermediate joint featuring a three-layer composite structure manufactured through co-extrusion molding technology, demonstrating exceptional mechanical strength and insulation properties. The connecting copper rod employed a segmented design consisting of hollow connection segments at both ends and a solid current-carrying segment at the center, ensuring optimal conductivity and mechanical load-bearing capacity. Moreover, its compact design facilitated efficient installation in spatially constrained work environments. Performance test results of the samples showed that all indicators of the device could meet the requirements of GB/T 12706.4—2020 and IEC 60502-4: 2010, having excellent insulation performance, voltage resistance, thermal stability, and dynamic stability, which could meet practical engineering application needs. Engineering validation demonstrated that compared with traditional repair methods, the technology could effectively overcome the limitations of conventional repair methods, achieving a 78.3% reduction in cost per fault repair and a 60% improvement in operational efficiency. Promotion and application of the technology could help reduce potential faults in distribution cable, improve power supply reliability, and have a significant effect on enhancing the safety and stability of long-term operation in distribution networks.