Question

Why do systems of 69 kV and greater not require shielding and grounding for lightning protection? What method is used to protect these systems?

A. These systems are inherently resistant to lightning strikes.
B. These systems have built-in lightning protection mechanisms.
C. These systems are designed with overhead shield wires for lightning protection.
D. These systems use surge arresters to divert lightning-induced surges.

Answer 1

High-voltage systems over 69 kV use overhead shield wires and surge arresters for lightning protection, diverting lightning strikes and voltage surges to earth.

Step-by-step explanation:

The question you've asked pertains to why systems of 69 kV and greater do not require additional shielding and grounding for lightning protection. These high-voltage systems are indeed designed to withstand and manage lightning strikes, but not because they are inherently resistant to lightning strikes (A) or have built-in protection mechanisms (B). Instead, they typically use overhead shield wires (C) and surge arresters (D) for lightning protection.

Overhead shield wires are installed above the power lines to intercept lightning strikes, thus protecting the lines beneath from direct strikes. Surge arresters are devices that protect electrical equipment from over-voltage transients caused by external (lightning) or internal (switching) events. They work by diverting the surge to earth, thus limiting the voltage that equipment is exposed to.