Analysis of the causes of faults in cross-linked cable joints

Analysis of the causes of faults in cross-linked cable joints

Operation status of cross-linked cable joints

6-10KV high-voltage power cables are widely used in water conservancy engineering and power systems, and their intact joints and accessories are crucial for the safe, economical, reliable operation and power supply safety of electromechanical equipment. A well-designed and well constructed cable joint has been proven to be suitable for long-term use in most cases through practical operation. However, due to its strong current carrying capacity and high current density, cross-linked cables have stricter requirements for the quality of conductor connections. The mechanical and electrical conditions required for the joints are becoming increasingly stringent, especially for 6-10KV motor cables. Various joints will be subjected to significant thermal stress and the impact of high intensity and duration of short-circuit currents. So cross-linked cable accessories are not accessory, let alone secondary components. They are equally important and essential components as cables, and are also key products closely related to safe operation. Crosslinked cables have been widely used abroad, and although they have only been widely used in China for more than 10 years, there are still some problems. However, with the development of technology, the matching of accessories, the improvement of quality, and the improvement of technology, cross-linked cables have become a trend to replace oil paper cables and have broad and far-reaching development prospects.

Analysis of the causes of faults in double crosslinked cable joints

Due to the variety, form, and specifications of cable accessories; Uneven quality; The technical level of construction personnel varies; The operating methods and conditions of cable joints vary, and the reasons for the failure of cross-linked cable joints vary. Due to the different media of cross-linked cables and oil-paper cables, there are significant differences in the causes of joint failures. The main cause of joint failure in oil-paper cables is insulation, while the main cause of joint failure in cross-linked cables is conductor connection. Cross linked cables allow for high operating temperatures, which puts higher demands on cable joints, making the problem of joint heating more prominent. Excessive contact resistance, accelerated temperature rise, and greater heat generation than heat dissipation cause the oxide film on the joint to thicken, resulting in higher contact resistance and faster temperature rise. Such a vicious cycle causes the insulation layer of the joint to be damaged, forming a phase to phase short circuit and causing explosion and burning.

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