2025-11-17
PVC cables are mainly used in medium and low voltage systems of 6/6, 6/10kV and below, with the largest application in 1kV distribution lines. PVC cables come in single-core, two-core, three-core, four-core, and multi-core configurations. A typical structure of a 1kV PVC power cable is shown in the figure. Most cables have a circular structure and lack a metal shielding layer. For special-purpose cables, such as some mining cables, airport lighting cables, and oilfield well cables, a single-core independent metal shield or a parallel flat structure may be used.
The structure of PVC insulated cables with a rated voltage of 6kV and above can be referenced from the cross-linked polyethylene cable structure diagram. These cables are less commonly used in practice.
Due to the widespread use of PVC insulated low-voltage cables in power distribution systems, regular testing and maintenance are rarely performed, resulting in a high failure rate. A significant portion of these cables operate with defects, often manifesting as high-resistance leakage faults between phases or between phases and ground, and open-circuit (broken line) faults.
Schematic diagram of 1kV PVC power cable structure
(a) Cross-sectional view of 1kV single-core cable; (b) Cross-sectional view and outline view of 1kV four-core cable;
(c) Cross-sectional view and outline view of 1kV three-core cable
1, 10, 18 - Polyoxyethylene outer sheath; 2, 5, 12 - Polyoxyethylene insulation; 3, 4, 11 - Conductor; 6, 14 - Filler; 7, 15 - Polyvinyl chloride tape; 8, 16 - Polyvinyl chloride inner sheath; 9, 17 - Steel tape reinforcement; 13 - Neutral conductor
