Overhead power cables are essential components of modern electrical transmission and distribution systems. They are used to carry electrical energy over long distances from generating stations to substations, and from substations to industrial, commercial, and residential users. Compared with underground cables, overhead lines are generally easier to install, inspect, maintain, and repair, especially in wide open areas or along long transmission corridors.The basic structure of an overhead power cable typically includes the conductor, protective layers, and supporting accessories. The conductor is usually made of aluminum or aluminum alloy, sometimes reinforced with a steel core to increase mechanical strength. Aluminum is favored because it is lightweight, cost‑effective, and has good electrical conductivity. In high‑voltage and extra‑high‑voltage applications, composite conductors and special aluminum alloys may be used to improve current‑carrying capacity and reduce line losses and sag.Insulation on overhead cables depends on the application. Traditional high‑voltage transmission lines often use bare conductors without external insulation, relying on air as the insulating medium and maintaining sufficient clearance from the ground and surrounding objects. For distribution networks in urban and suburban areas, insulated or covered overhead cables are widely used to improve safety, reduce the risk of short circuits from branches or wildlife, and allow more compact line routing. The insulating materials are typically cross‑linked polyethylene (XLPE) or similar weather‑resistant polymers.Mechanical performance is a key consideration in overhead cable design. Cables must withstand wind, ice, temperature variations, and mechanical tension over their service life. The thermal expansion and contraction of the conductor are carefully calculated to control sag between towers, ensuring adequate ground clearance under the highest operating temperature. Supporting structures such as poles, towers, insulators, and hardware fittings are selected based on span length, environmental conditions, and electrical load.Electrical performance includes current‑carrying capacity, permissible operating temperature, corona discharge characteristics, and electromagnetic compatibility. For long‑distance, high‑voltage transmission, minimizing line losses and improving efficiency are primary goals. Bundle conductors may be used at very high voltages to reduce corona losses and radio interference. In distribution networks, attention is focused on reliability, voltage regulation, and safety in densely populated areas.Overhead power cables must comply with national and international standards governing conductor materials, mechanical properties, electrical characteristics, fire behavior, and environmental impact. Increasingly, environmental and aesthetic factors are considered in line design, especially near residential zones and environmentally sensitive areas. Modern overhead systems may integrate monitoring devices for temperature, sag, and line faults, supporting smart grid applications and improving operational reliability.Overall, overhead cable power systems offer a cost‑effective, flexible, and technically mature solution for transmitting and distributing electrical energy. Their design balances electrical performance, mechanical strength, safety, and environmental considerations to ensure stable and efficient power supply.