Introduction to Electricity Pylons

Function

• Support Conductors (Wires): To erect transmission conductors to a sufficient safe height above the ground.

• Ensure Safe Clearance: To maintain safe distances between the conductors and the ground, buildings, trees, and other crossed facilities (e.g., roads, railways, communication lines).

• Withstand Natural Forces: To bear the weight of the conductors themselves, as well as wind pressure, ice load, and the impact of natural disasters such as earthquakes.

Main Structural Components

• Top (Tower Head): The uppermost part of the pylon, used for installing insulator strings and suspending conductors.

• Body (Tower Body): The main part of the pylon, connecting the top and the legs, providing the primary structural support.

• Crossarm: Arm-like structures extending from the tower body, used for securing insulator strings and conductors.

• Leg (Tower Leg): The legs of the pylon, supporting the entire tower body, typically connected to the ground via the foundation.

• Foundation: The part buried underground, transferring all loads borne by the pylon to the ground, fundamental to the pylon's stability.

• Ancillary Facilities: Include ladders, platforms, warning lights, aircraft warning spheres, bird deterrent devices, and grounding devices.

Classification of Pylons

By Function/Purpose:

• Tangent/Suspension Tower

• Strain/Dead-end Tower

• Angle Tower

• Terminal Tower

• Crossing Tower

• Transposition Tower

By Number of Circuits:

• Single-circuit Tower

• Double-circuit Tower

• Multi-circuit Tower

Voltage Levels

• Low Voltage (LV): < 1 kV (Often use concrete poles, rarely pylons)

• High Voltage (HV): 10kV, 35kV, 110kV

• Extra-High Voltage (EHV): 220kV, 330kV, 500kV

• Ultra-High Voltage (UHV): 750kV, 1000kV (AC), ±800kV (DC)