Overhead power lines act like "aerial power corridors" in cities, using poles and towers to suspend conductors in the air and transmit electricity from power plants to homes. The core principle is the use of conductors to carry current, which is then isolated from the poles and towers by insulators, ensuring the safe and directional transmission of current.
The entire system consists of several components working together:
Conductors: Responsible for conducting current, typically made of aluminum or copper. High-voltage lines often use split conductors to reduce corona loss.
Insulators: Insulate the conductors from the poles and towers, preventing current leakage. Common types include porcelain, tempered glass, and composite materials.
Poles and Crossarms: Support the conductors and maintain safe phase-to-phase distances. Concrete poles or angle steel towers are widely used in various terrains.
Hardware: Connects and secures various components, such as clamps and bolts, ensuring structural stability.
Lightning conductors: Erected above the conductors, they conduct lightning current to the ground during thunderstorms, protecting the line.
In addition, overhead lines also need to be designed to withstand wind, vibration (such as using vibration dampers), and flashover, in order to cope with the impact of complex environments.