What is the most common source of transient voltages on utility power distribution systems?

The most common source of transient voltages on utility power distribution systems is lightning. Lightning strikes can induce high-voltage surges in power lines, leading to significant transients that can affect equipment and systems connected to the distribution network. When lightning occurs, it generates a large amount of electrical energy that can create sudden voltage spikes, causing disturbances in the power system.

These surges can propagate through the power distribution network and result in various issues, such as equipment damage, operational disruptions, and safety risks. Understanding the impact of lightning on power distribution systems is crucial for designing effective surge protection mechanisms and ensuring the reliability of electrical infrastructure.

While other sources like lighting dimmer controls, motors, and variable frequency drives can also generate transients, they are generally less significant in terms of magnitude and frequency compared to the effects of lightning. Lightning is therefore recognized as the primary cause of these voltage transients in utility power systems.