Why Power Lines Make That Annoying Buzzing Sound (And How It's Usually Prevented)

In this modern, technologically inclined age, power is crucial for all aspects of daily life. Keeping the lights on, running computers and appliances, giving those in poor health proper care, and more require electricity, which is why there are so many power lines — just one of many elements in the United States' fascinating power grid system. They serve as pathways to move electrical energy from one location to the next, thus allowing society to function in the ways we've all grown accustomed to. As valuable as power lines are, though, there are elements of them that can lead to confusion.

Most strange is the sound they can emit, which is often described as a downright annoying buzzing sound. So, what's the reason for this seemingly random, grating noise? In short, this noise is due to a phenomenon called corona discharge, an energy discharge within the power lines themselves. When the surface of the conductor has a greater electric field strength than the surrounding air, this buzzing is more than likely to happen. It's also common for different air conditions, including heightened humidity levels, precipitation, wind, and more, to increase the buzzing.

Corona discharge isn't supposed to occur in power lines, yet it's far from uncommon. In response, a couple of things have been done to prevent it from happening as much as possible.

Seeing as corona discharge endures as an issue for some power lines; there isn't necessarily a concrete method out there for preventing it. However, that's not to say that attempts haven't been made to mitigate it and the sound that comes with it. One solution is the use of corona rings, which attach to the ends of power line insulators — the small tower of rings seen at the top of some utility poles, not to be confused with the orange balls on power lines that serve a much different purpose — and reduce the effects of corona discharge. They work to redistribute the energy that would otherwise build up and interact with the air around power lines, resulting in all that comes with corona discharge.

Alternatively, there's another method worth trying to reduce corona discharge and its irritating sound. If corona rings aren't an option, increasing the insulation on power lines is a solid second option. With a thicker barrier between the electrical wires and the surrounding air, the reaction between them that causes corona discharge is significantly reduced. Unfortunately, it has been observed that, should it begin, corona discharge can do a number on insulation material. Positive and negative ions in the air can create secondary ions that damage insulation, and as a result of this, localized overheating at specific points in the insulation can become a concern.

With all of the damage it can do to power lines, it's no surprise that corona discharge isn't solely characterized by buzzing. It makes itself known in other ways, with one being significantly more concerning than the other.

If you hear the signature buzz or hiss of corona discharge, odds are you'll probably see another sign of its presence. It's not unheard of for power lines plagued with corona discharge to give off a bluish glow. This is commonly seen when there is added moisture in the air, as the electrical field of the power line ionizes the fluid in the air and causes it to glow. The buzzing and glow might also be accompanied by an unusual smell, potentially similar to bleach. This is the scent of ozone gas, the release of which is a clear indication that corona discharge is taking place.

Should power lines begin emitting ozone due to corona discharge, they could become an active danger. Inhaling excessive ozone is known to lead to coughing, chest tightness, trouble breathing, and other similar ailments. As far as what it can do to power lines, ozone is capable of significantly reducing the effectiveness of its insulation and conduction elements. This damage, should it get far enough along, could lead to energy loss in the affected lines and the generation of sparks. This could lead to sudden fires if not monitored closely and the necessary components are not replaced.

Though it may start out as little more than some unusual buzzing, corona discharge in power lines should be taken seriously. If not, it could result in more than just an auditory nuisance. Surviving a power outage is far from impossible, but we're all best off avoiding such a major inconvenience if possible.