Harmonics might be more dangerous than we thought…
Have you ever had someone turn on the tap at a sink while you were taking a shower only to be rudely interrupted by a change in your water temperature? I like to use this as a demonstration to show the similarities to what happens to a buildings power supply when affected by harmonic interference. Power wanes or surges, and instead of just an uncomfortable temperature, as in the shower, electrical equipment can actually heat up to the point of failure.
Harmonic interference really wasn’t a concern until recently when harmonic-generating equipment such as personal computers, fax machines, laser printers and variable frequency drives invaded our everyday lives. And now we have to do something about all of these power quality issues.
Variable-speed drives controlling pump or air-handling unit motors like you have in your heating and air conditioning systems became the norm, because varying or lowering the speed of these motors is more energy-efficient. Variable-speed drives allow a motor to operate over a range of speeds to adjust to a particular situation. This range can increase efficiency by using less power when it is not needed. However, the variable-speed drives produce harmonics in the power conversion process. And, we started using electronic ballasts in building lighting systems, because they were more energy-efficient than magnetic ballasts. These changes introduced higher efficiencies, but they also increased the problems of harmonic interference.
“One source of distortion by itself may not be a problem, but connected with other equipment producing their own distortions, the resulting total harmonic distortion can make other equipment operate incorrectly, lose data or actually fail,” explains Ray Lewis, P.E., senior electrical engineer in the Fort Worth Facilities Unit of Carter & Burgess.
I’d like to also share this quote from Ray Lewis. “Getting harmonics under control can save dollars and energy, as well as equipment and data. In real life, this is evident particularly in data centers full of computers. The computers must be kept cool. If harmonics are causing equipment to heat up, air conditioning systems are using more energy to cool down the room.”
Here is also another example of harmonic distortion that sometimes you can hear! Have you ever heard distortion in your telecommunication lines? This can disrupt production, not to mention your conversation and even your internet connection! This type of harmonic distortion is a result of your telecommunication lines running right next to your power lines.
Harmonic interference left not dealt with is simply asking for trouble. Heat buildup in your electronics is just not healthy. And now knowing that these harmonic distortions can actually leak into telecommunication lines, what do you think they can do to you? A study by Havas and Stetzer says this: Exposure to electromagnetic fields has been associated with an increased incidence of childhood leukemia and miscarriages with residential exposure and with an increase in adult leukemia, brain cancer, and breast cancer with occupational exposure (see review by Havas 2004). In addition to these serious illnesses, an
increasing number of people claim to be electrically sensitive. Symptoms include headaches, flu-like symptoms, chronic fatigue, fibromyalgia, poor quality sleep, tightness in the chest, eye discomfort, skin disorders, dizziness, nausea, and difficulty concentrating (Levallois, 2002). WOW, that’s pretty serious of you ask me.
So what can we do about this? One of the simplest and most cost effective ways to deal with harmonic distortion is to have a qualified electrician install a harmonic filtration system at your power source in your home or business. If you have to work in an environment that concerns you, speak to an electrician, have them go to your place of business and speak with the owner about your concerns. To get more information of what I recommend in everyone’s electrical system, click this link for a product that works: Monyer Electric PFC Products(Noise Filtration)