What is the purpose of shield or static wires?

The purpose of shield or static wires is primarily to provide a path to ground for lightning surges. These wires are typically installed above the conductors of overhead power lines. When a lightning strike occurs, the shield wire acts as a protective conduit, directing the electrical energy safely to the ground rather than allowing it to travel down the transmission lines. This mitigates the risk of damage to the transmission infrastructure and connected equipment, ensuring the safety and reliability of the electrical system.

In addition to their primary function in lightning protection, shield wires can also help reduce electromagnetic interference and protect against surges, but their main purpose remains focused on grounding lightning strikes.