How to Protect Transmission Lines and Substations from Direct Strokes:

• Lightning Arrestors or Surge diverters: 

Surge diverters or Lightning arrestors function by providing a low-impedance path to ground for transient over voltages that exceed a certain threshold. When a surge occurs, such as from a lightning strike or switching operation, the surge diverter conducts the excess energy to ground, effectively diverting it away from sensitive equipment.

• Over Head Grounding Wires: 

The ground wires are grounded at each tower or pole through as low resistance as possible. Due to their proper location, the ground wires will take up all the lightning strokes instead of allowing them to line conductors. 
When the direct lightning stroke occurs on the transmission line, it will be taken up by the ground wires.

• Earthing Screen: 

An earthing screen consists of a network of copper conductors (often called a shield or screen) mounted all over the electrical equipment in the substation or power station. By connecting the shield to the ground at two points (at least), it provides a low-impedance path through a resistor, diverting lightning currents away from critical equipment.