Harmonic distortion is also known as harmonics. Harmonics are distortions in the mains power network which can lead to poor power quality, an unreliable power network, and eventually to equipment damage.
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Early planning and mitigation of harmonics helps you to
Specify harmonic mitigation correctly, for more cost-efficient projects in both the CAPEX and OPEX phases:
Manage risk of electrical inefficiencies due to unchecked harmonic distortion:
Did you know that network operators work hard daily, to bring us high-quality power in the electrical network? It’s an ongoing task to ensure that the power delivered to our homes and factories is clean alternating current, free of harmonic distortion.
When drawing power from the network, the network supply can become distorted by the loads that are connected to it. This power distortion includes harmonic components.
For factories and other industries, harmonics and other power distortions cause problems that cost money, such as:
Harmonic distortion in electrical systems damages equipment by causing overheating, voltage stress, and energy losses, which strain components and reduce their lifespan. The effects of more harmonic distortion are far-reaching, as they affect every piece of electrical equipment connected to the same system.
Excessive harmonic distortion can cause cables and motors to overheat. Motors, switchgear, fuses, cables, and sensitive measuring equipment are all impacted. Distortion with harmonic content can even interfere with critical telemetry and communication devices like Wi-Fi systems.
This can lead to premature equipment failure, such as blown fuses, tripped circuit breakers, or overheated motors, potentially affecting the entire industrial plant if no corrective measures, like harmonic filters or power quality improvements, are implemented.
The image shows the influence of harmonic distortion generators in overheating of electric motors.
Harmonic distortion increases power bills by increasing system losses and reducing overall system efficiency.
This wasted energy is a major operating cost issue for industrial users.
To reduce the total bill whilst still getting the same amount of useful power, we need to reduce harmonic distortion.
Electricity bills are made up of active and reactive power. Only the active power is usable, but we pay for both components. The extra cost can impact profitability.
Power distortions, including harmonics, are more than just annoying. They can stop your processes, causing downtime and interruptions to your production lines. They also affect the CAPEX when purchasing equipment and fuels to operate your plant, which has a major impact on operating cost targets.
Harmonic distortion and distortion in general also impact greenhouse gas (GHG) emission targets across all Scopes (Scope 1, 2 and 3 emissions). Distortion of the power supply results in these undesirable outcomes:
The good news is that harmonic distortion, including higher frequency harmonics and lower order harmonics, can be mitigated. By putting measures in place to keep voltage distortion at low levels, you can:
Harmonics cause unreliability in networks by distorting the electrical waveforms, which can negatively affect the performance of sensitive equipment and systems. As more non-linear electrical devices are added to a system, the system becomes more vulnerable to these distortions. Therefore, it is important to consider harmonics and how to mitigate them, to build a resilient system that does not fail.
AC drives bring a multitude of benefits to your system, especially in reduced energy consumption. At the same time, they generate more harmonics - and can also mitigate these harmonics produced. The reason to use AC drives is that their benefits far outweigh the drawbacks of harmonics produced. Discover the benefits in this video.
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AC drives, also known as variable speed drives (VSDs) or variable frequency drives (VFDs), offer the best way to de-carbonize your operation and meet your carbon neutrality targets. These drives regulate electric motors to reduce energy consumption dramatically. They also bring controllability, repeatability, and resilience to industrial processes. Drives are an integral part of the modern industrial landscape, bringing enormous benefits:
New installations can reduce energy consumption by equipping each application with AC drive control. Upgrading existing direct-on-line (DOL) or fixed speed installations to drives is the best way to achieve greenhouse gas (GHG) reduction goals 1]. Upgrading to high-efficiency motors helps even more.
1] OMDIA COP26 global report: If all fans and pumps globally were equipped with VSDs, the savings would equal the entire power generation capacity of the EU. By employing drives, GHG emissions can reduce by 40% by the year 2040.
There is a lot of money to save, and many other benefits. to be won, by mitigating harmonics properly. However, there is no single solution for all scenarios. It’s a matter of selecting the best method for each individual installation. In some cases, you can achieve compliance with no mitigation at all, so don't buy what you don’t need!
Consider dealing with a manufacturer that understands the challenges and can offer you the best advice for your exact system and circumstances. Danfoss offers the widest range of solutions to mitigate harmonic distortion, in high or low power range, compatible with any motor technology, to suit any situation. We help you to find the most efficient and economical solution.
Modern drives (and filters) from Danfoss can mitigate harmonics and manage the harder issues like supra harmonics and common mode. There is no single solution for all scenarios. Have questions? We can help.
The full range of harmonic mitigation solutions includes:
For planners: To find the optimal mitigation solution try our digital tool, MyDrive® Harmonics.
To learn more about harmonic distortion and how to mitigate them, check the FAQ topics below, and read our blog.
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Harmonics are not visible, but their effects are. Harmonic distortions are repetitive and continuous deformations of the clean voltage or current waveforms.
Using Fourier analysis, a technique developed by the French mathematician, we can visualize the magnitude of harmonics present in the system.
Fourier showed that any distorted waveform is just a set of individual sine waves of different frequencies and amplitudes added together. The distorted waveform is made up of a sinusoidal fundamental curve, plus harmonics.
It is these individual higher order sine waves that are known as harmonics. Usually, we refer to power distortions in the frequency range under 2 kHz as “harmonic distortion”.
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Harmonic distortion of the waveform originates from non-linear loads connected to the power supply. All loads that draw non-sinusoidal current are referred to as non-linear loads. The biggest contributors to harmonics are:
To reduce damage to equipment, regulations limit harmonics to low levels in power supply networks. Mitigation is not always necessary, but when required, harmonic mitigation devices can reduce harmonics to comply with these regulations. For successful harmonic mitigation there are many methods to choose between, including the use of harmonic filters, active front-end (AFE) drives, and more.
Contact one of our application experts for advice.
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DENMARK: Universe Science Park saves on both power bill and emissions for its wind tunnel attraction “Beat the Storm”, with the intelligent VLT® HVAC drive.
In the University Medical Centre (UMC) Ljubljana air conditioning system, Danfoss drives with integrated filters ensure low harmonic distortion, with maximum THDi of 5%.
ROMANIA: Digitizing irrigation systems helps farmers achieve better harvests. Pumping stations now use 30-40% less energy and use water more efficiently too.
VLT® AutomationDrive FC 302 and VLT® Soft Starter MCD 500 provide quick and accurate control of high- and low-pressure seawater pumps on the remotely operated trencher laying HVAC subsea cables.
NORWAY: VLT® AQUA Drive FC 202 ensures dependable uptime with stringent harmonic compliance at Nordlaks Smolt AS.
UNITED KINGDOM: Jersey Water chose VLT® AQUA Drive from Danfoss when needing a major upgrade at its La Rosière desalination plant.
Harmonic mitigation reduces unwanted frequencies in electrical systems, preventing equipment damage, and improving power quality and efficiency.
Harmonic distortions can lead to breakdowns and damage in electrical systems. Reduce risk and minimize downtime with filters and low harmonic drives, LHD and ULH, from Danfoss.
Danfoss is the global power converter and VFD manufacturer delivering efficient optimization of any electric motor or system, since 1968. We are committed to improving productivity, efficiency and emissions for a wide range of industries, OEMs and system integrators, making Danfoss Drives a reliable manufacturer of your drives.
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