What is the function of a lightning arrestor?

The function of a lightning arrestor, commonly known as a lightning arrester, is to protect electrical facilities from voltage surges caused by lightning strikes or other sources of over-voltage. This device is designed to divert excess voltage away from sensitive equipment and into the ground, thereby preventing damage from high-voltage transients that can lead to failures in electrical systems.

When lightning strikes a power line or nearby structure, it can introduce a sudden rush of electrical energy that could potentially harm transformers, circuit breakers, or other critical components in the system. By providing a path for this high voltage to dissipate safely, lightning arrestors play a crucial role in maintaining the integrity and reliability of electrical infrastructure.

In contrast, the other options describe functions that do not align with the primary purpose of a lightning arrestor. Calculating electrical load on transmission lines is a different process involving load monitoring devices. Automatic line reclosure deals with circuit protection after a fault occurs, while conducting tree inspections focuses on maintaining clearances and minimizing vegetation-related outages, neither of which pertains to the voltage surge protection role of lightning arrestors.