Basic Structure of Power Cables:
The basic structure of power cables consists of four parts: the core (conductor), insulation layer, shielding layer, and protective sheath.
1. Wires. The core is the conductive part of the power cable, used for transmitting electrical energy and is the main component of the power cable.
2. Insulation. Insulation serves to electrically isolate the core from the ground and between cores of different phases, ensuring power transmission and is an indispensable part of the power cable structure.
3. Sheath. Power cables above 15KV typically have both conductor sheath and insulation sheath.
4. Protective Layer. The role of the protective layer is to shield power cables from external impurities and moisture, as well as to prevent direct physical damage to the cables.
Flame Retardant/Fire Resistant Power Cables. The flame retardant grade is indicated by adding "A", "B", or "C" after the letter "Z", such as "ZA", "ZB", "ZC". When "ZR" is used, it is generally considered to be "C" grade flame retardant. The indication for flame retardant fire resistance grade is by adding "A", "B", or "C" in the middle of "ZN", such as "ZAN", "ZBN", "ZCN". When "NH" is used, it is generally considered to be "ZCN". For example:
Model Name Equivalent
ZC-YJV Copper Core Cross-Linked Polyethylene Insulated Sheathed Flame Retardant C-Level Power Cable, ZR-YJV
ZCN-YJV Copper Core Cross-Linked Polyethylene Insulated and Sheathed Flame Retardant C-Level Fire Resistant Power Cable, NH-YJV

Power cables: To ensure the normal operation of the cables and motors, the following three principles should be adhered to when selecting the cable cross-section:
1. During normal operation, the actual temperature rise of the cable should not exceed the maximum temperature rise allowed by the insulation.
2. Select based on the allowable voltage loss during cable line operation.
3. The selection of cable cross-section must meet the requirements for mechanical strength.

Key Advantages of Power Cables:
1. Takes up minimal space: Generally buried in the soil or laid indoors, in trenches or tunnels, with small inter-line insulation distances, no need for towers, occupying minimal ground space, and hardly taking up any above-ground space.
2. High Reliability: Minimal affected by climate and surrounding environmental conditions, stable transmission performance, with high reliability.
3. More favorable conditions for development towards higher pressure and larger capacity, such as low-temperature, superconducting power cables, etc.
4. Large distributed capacitance.
5. Low maintenance workload.
6. Low risk of electric shock.