What are the two types of abnormal voltage on a line?

The two types of abnormal voltage on a line are typically associated with external influences or operational changes that can adversely affect the electrical system. In this case, switching and lightning represent two significant phenomena.

Switching abnormal voltage can occur when electrical circuits are opened or closed, leading to transients and spikes in the voltage levels. These events can be caused by operations on the power system, such as disconnecting or connecting loads, and can produce voltage surges that may affect equipment and system stability.

Lightning, on the other hand, generates extremely high voltage transients during storms when it strikes power lines or nearby structures. These surges can induce high voltages in electrical systems and can pose a risk to both equipment and safety.

Understanding these types of abnormal voltages is crucial for linemen and electrical engineers, as both can lead to electrical failures or damage if not properly managed and mitigated. Knowing how to recognize and respond to these occurrences helps maintain system reliability and safety.