Buzz Kill: Here’s Why High-Voltage Power Lines Make Noise

If you have worked on—or walked under—high-voltage power lines, odds are you have probably heard the buzzing noise that comes from lines. Why do power lines buzz like that? Is it static discharge? Vibration from a 60-cycle field? The high-voltage experts at North Central Electric are here to spill the secrets so you can learn once and for all what all that buzzing is about.

The Cause of the Noise

The audible noise you hear from high-voltage cables occurs because of the energy that is being discharged. This discharge happens when the conductor surface’s electric field surpasses the breakdown strength of the surrounding air, resulting in a discharge. This discharge isn’t just noisy—it can also create a radio noise, emit a faint visible glow near the conductor, and lead to an energy loss known as corona loss. Additionally, an energy loss known as corona loss, as well as other occurrences associated with high-voltage lines, are also a direct result of this discharge.

These effects are all part of the complex phenomena associated with high-voltage lines and are important considerations in cable testing to ensure safe and reliable operation.

Factors That Increase the Noise

Environmental factors can intensify the noise coming from high-voltage lines. Humidity, air density, wind, and moisture from rain or fog all increase air conductivity—and the accompanying noise. Because these elements increase the conductivity of the air, the intensity of the corona discharge increases, and so does the noise you end up hearing. In other words, the sound is likely to be louder on a humid day than on a dry day. In addition to the elements of the air, other factors can lead to noisy, high-voltage lines, such as nicks or sharp points in the wiring, airborne contaminants, or weathering on the conductor’s surface. This is why regular maintenance and cable testing are essential to identify and manage factors that could amplify the noise.

Why Modern Lines are Experiencing an Increase in Noise

Why do power lines buzz now more than ever? Due to the fact that modern transmission lines have higher voltages, this increased power has increased the noise problem—so much so that it has become a concern to those in the power industry. As a result, certain high-voltage lines are being designed, constructed, and maintained in ways that enable them to operate below the corona-inception voltage in dry conditions. This means that, under normal conditions, these lines produce minimal corona-related noise. However, when adverse weather occurs, the corona discharge is still challenging to control and may not be able to be stopped. The best way to ensure your high-voltage lines are functioning safely and properly is to get them routinely tested and analyzed, as this helps identify any issues before they escalate.

Whether your high-voltage cables need Hipot Testing or Tan Delta Analysis, or you are looking for a Fault Locating service, the NCE team will ensure that your high-voltage cables are properly maintained and tested. Contact us today to learn more about our electrical services and how we can help keep your high-voltage systems reliable and safe.