If you have worked on—or walked under—high-voltage power lines, odds are you have heard a buzzing noise coming from the lines. Most people, however, do not know why power lines actually buzz. Is it static discharge, what is that noise? Vibration from a 60-cycle field? The high-voltage experts at North Central Electric are here to spill the secrets, so you can know once and for all what all that buzzing is about.
The Cause of the Noise
The audible noise that can be heard from high-voltage cables occurs because of the energy that is discharged. This discharge occurs when the conductor surface’s electric field strength is greater than the breakdown strength of the air that is surrounding the conductor. This discharge also creates radio noise, a visible glow of light near the conductor. Additionally, an energy loss known as corona loss, as well as other phenomena associated with high-voltage lines, are also a direct result of this discharge.
Factors That Increase the Noise
The condition of the air—meaning the humidity, air density, wind and moisture from rain and fog—can all cause high-voltage lines to emit a noise. Because these elements increase the conductivity of the air, the intensity of the corona discharge increases, and so does the noise. In addition to the elements of the air, other factors can lead to noisy high-voltage lines. These factors include: nicks or sharp points in the wiring, airborne contaminants and weathering of the conductor surface.
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 enables them to operate below the corona-inception voltage in dry conditions—this means that the line will generate a minimum of corona-related noise. However, when foul weather occurs, corona discharge is not 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.
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!