The five fundamental components of an overhead power line system are:

1. Conductors: These are the wires that carry the electrical current. They are typically made of materials like aluminum or aluminum-steel composite (ACSR) to balance high electrical conductivity with mechanical strength.

2. Line Supports: These are the structures, such as poles or towers, that physically hold the conductors aloft. They must be strong enough to withstand the weight of the conductors, wind loads, and other environmental stresses.

3. Insulators: Insulators are essential for safely attaching the conductors to the line supports. Made from non-conductive materials like porcelain, glass, or polymers, they prevent electricity from flowing from the conductors into the supports and to the ground.

4. Cross-Arms: These are horizontal beams attached to the line supports that provide the necessary horizontal spacing between the conductors and the insulators. This spacing prevents the wires from touching and causing short circuits.

5. Ground Wires and Lightning Arresters: These components are crucial for protecting the power line from over-voltage events, particularly lightning strikes. A ground wire runs along the top of the towers to intercept lightning, while lightning arresters divert surges safely to the ground.