For high-voltage cables, the main types we can observe include overhead lines on utility poles and underground cables in utility tunnels. The selection of high-voltage cables involves highly complex considerations due to their extensive variety. Below, we will explore the principles and requirements for high-voltage cable selection.

Structure of High Voltage Cables

The components of a high-voltage cable from the inside out include: conductor, insulation, inner sheath, filler (armoring), and outer insulation. Of course, armored high-voltage cables are primarily used for underground applications, as they can withstand high-intensity pressure from the ground surface and prevent damage from other external forces.

Types of high-voltage cables

The main types of high-voltage cables include YJV cables, VV cables, YJLV cables, and VLV cables.

YJV cable, the full name of cross-linked polyethylene insulated polyvinyl chloride sheathed power cable (copper core)

The full name of VV cable is polyvinyl chloride insulated and sheathed power cable (copper core)

YJLV cable stands for Cross-linked Polyethylene Insulated Polyvinyl Chloride Sheathed Aluminum Core Power Cable

VLV cable, full name Polyvinyl Chloride Insulated and Sheathed Aluminum Conductor Power Cable

High Voltage Cable Selection

1. The buried type refers to the direct laying of high-voltage cables underground (with varying burial depths depending on geological conditions, generally exceeding 0.7 meters). This method imposes higher protection requirements on the cables themselves, making it suitable for armored cables with external protective layers. For unstable geological conditions such as marshes or quicksand, steel-wire armored cables can also be selected. (Actually, the armored cables we discuss are a flexible composite, characterized by their rigidity, varied internal materials and conductors, and insulated metal sheathing.)

2. The duct method involves laying high-voltage cables within pre-fabricated conduits. This installation approach can easily lead to cable overheating, resulting in power loss and reduced capacity. Therefore, it is more suitable for using plastic-sheathed cables or bare armored cables.

3. Tunnel type refers to the method of laying high-voltage cables on cable trays or supports within cable tunnels. This method is commonly used in urban areas, offering advantages such as good heat dissipation and easy maintenance. However, it imposes higher requirements on cable flame retardancy, making it suitable for bare armored cables or flame-retardant plastic-sheathed cables.

4. Overhead type refers to the laying method where high-voltage cables are connected and installed via poles (utility poles). This method is suitable for areas with flat terrain and minimal elevation changes. However, it exposes the cables entirely to the open space, making them vulnerable to external environmental factors and mechanical impacts. Therefore, cables with outer sheathing or all-plastic types are recommended for such installations.