Cable installation methods include direct burial, duct installation, shallow trench installation, cable trench installation, cable tunnel installation, and aerial installation. From a technical standpoint, cable tunnels and cable trenches are preferable installation methods because they facilitate cable construction as well as maintenance and inspection. In some developed cities, public utility tunnels have been incorporated into urban planning and development.

　　Practice has demonstrated that the use of utility tunnels yields excellent results, significantly reducing the frequency of redundant investments and repeated road excavations; however, the initial capital outlay is substantial. In China, due to a variety of influencing factors, this installation method remains relatively uncommon. By contrast, direct burial and shallow trench installation are more cost-effective approaches, yet they pose challenges for the maintenance and inspection of cable systems. Once a cable fault occurs, even with the aid of fault-location equipment, the cable trench must still be reopened, which is rather inconvenient.

　　Therefore, the selection of cable laying methods should be based on actual conditions and tailored to the specific project requirements, taking into account factors such as environmental characteristics, cable type, and cable quantity. From a developmental perspective, the chosen method must ensure operational reliability while meeting the requirements for ease of maintenance and adhering to principles of technical soundness, economic efficiency, and overall rationality.

　　Selection of cable engineering structures: Commonly used power cables include oil-immersed cables, polyvinyl chloride–insulated cables, and cross-linked polyethylene cables. Depending on the specific application, the range can be expanded to include various specialized cable types. Currently, with continuous improvements in manufacturing technologies and processes, cross-linked polyethylene cables have become a widely used cable product. When selecting cables, the choice should be based on the specific operating environment and conditions, taking into account the particular application requirements. For example, when cables are laid directly underground or in shallow trenches, steel-armored cables should be considered.

　　Due to the large outer diameter of cables used in cable projects, transportation and installation are challenging, and power cables have strict requirements for minimum bending radii. During power cable installation, excessive bending can cause mechanical damage to the conductor; however, because this damage is concealed by the cable insulation, it is often undetectable. Even routine tests such as loop resistance measurement, insulation testing, and leakage current testing may fail to reveal such defects. During operation, damaged sections can overheat, leading to a reduction in the cable’s insulation strength until a failure ultimately occurs.

　　During construction, it was found that a common cause of cable termination failures in cable projects is the practice of fabricating all three cable terminations to the same length. When connecting to equipment, however, terrain constraints often result in the middle-phase termination being forced into an arched configuration, leading to damage at the termination root and subsequent partial discharge. After implementing corrective measures—specifically, appropriately shortening the connection length of the middle-phase termination based on the particular connection requirements of each piece of equipment—the three-phase terminations are no longer subjected to external mechanical stresses. Field experience has demonstrated excellent operational performance. Therefore, during cable installation, it is essential to minimize torsional stress on the cable as much as possible; when routing and spooling the cable, allow it to bend naturally to prevent internal mechanical damage.