(1) Classification of low-voltage power cables
Low-voltage power cables are generally divided into polyvinyl chloride insulated (plastic) power cables, XLPE insulated power cables, rubber insulated power cables, oil-filled and oil-impregnated paper insulated power cables according to their insulation types, and can be divided according to their work types and properties. It is a type of general ordinary power cable, overhead power cable, mine underground power cable, submarine power cable, fire-resistant (fire-resistant) flame-retardant power cable, etc.
(2) Several commonly used low-voltage power cables and their characteristics
1. Copper core conductor power cable
At present, all low-voltage power cables in China are twisted together by each core wire. The cable with this structure has poor anti-interference ability and poor lightning resistance performance. The three-phase impedance of the cable is unbalanced and the zero-sequence impedance is large, which makes it difficult to protect the line. Electrical appliances operate reliably, etc. The copper and aluminum PVC copper core conductor power cables with rated voltages of 0.6kv ~ 1kv
2. XLPE insulated power cable
Referred to as XLPE cable, it uses chemical or physical methods to change the molecules of the cable’s insulating material polyethylene plastic from a linear structure to a three-dimensional network structure, that is, to convert the original thermoplastic polyethylene into a thermosetting cross-linked polyethylene. Plastic, which greatly improves the heat resistance and service life of the cable, and still maintains its excellent electrical properties.
3. PVC insulated PVC sheathed power cable
The long-term working temperature of PVC insulated and PVC sheathed power cables does not exceed 70 °C, and the maximum temperature of the cable conductor does not exceed 160 °C. The longest duration of short circuit shall not exceed 5s, and the minimum temperature of construction and laying shall not be lower than 0℃.