What is Harmonic Mitigation?

What is Harmonic Mitigation?

In simple terms, harmonics are extra frequencies that when present in an electrical circuit, distort the AC sine wave. A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency.

For example, if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f, . . . etc. Harmonic frequencies are equally spaced by the width of the fundamentalfrequency and can be found by repeatedly adding that frequency. In the case of the Australian electricity supply, the fundamental frequency is 50Hz. The frequencies of the harmonics are 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz and so on. 150Hz is called the 'third' harmonic (3 x 50Hz), 250Hz is called the 'fifth' harmonic (5 x 50Hz), etc. The presence of harmonics in an electrical system distorts the clean shape of a sine wave.

Power Quality Products

 

How do you know if you have harmonics in your electrical system?

If you occasionally experience some unexplained occurrences such as flickering lights, alarms going off, or MCB's, MCCB's, RCD's and Earth Leakage devices tripping for no apparent reason, you are most likely experiencing harmonics in your electrical environment. Other signs are cables running hot, hot switchboards or overheating motors. If you are replacing your motor's bearings & insulation often, that's a strong indication of the presence of harmonics.

FAQs on Power Quality


What are the effects of harmonics in your electrical system?

Harmonics are very harmful within an electrical system and can have serious consequences. For example, the presence of harmonics reduces the life of equipment. It is possible that the investment that you made in your motors & drives will not be realised if they are damaged and need replacing before their expected life span. This can be very expensive.

Harmonics cause things to run hot, which cause stress on the cables and equipment. In the long term, this degrades an electrical system. The presence of harmonics will also mean that although you will get billed for the power that you are supplied, a large percentage of that power may be unusable. Harmonic mitigation is taking action to minimise the presence of harmonics in your electrical system and can achieve great cost savings.

Variable Speed Drives (also known as Variable Frequency Drives) are prolific creators of harmonics in electrical systems and as a result, most of the harmonic mitigation effort focuses on the input side and output side of a VSD.


Download our Power Quality Catalogue

 

Different types of Harmonic Mitigation devices



Depending on the specific situation, there are a variety of products that are used to mitigate harmonics. Fuseco's Power Quality Consultants can assist by conducting a site analysis or simply providing advice based on the details of the particular electrical system. Here is a brief summary of the product groups:


Input (Line) side of the VSD (VFD)


Line Reactors

  • Also known as Inductors, Chokes & Line Filters.
  • For use on the input of a VSD / Inverter or other non-linear devices.
  • Virtually eliminate nuisance tripping.
  • Extend life of semiconductors.
  • Reduce harmonic distortion.
  • Reduce surge currents.
  • Improve true power factor.


Passive Harmonic Filters

  • Also known as 'Low Pass Filters'.
  • For reducing harmonics at the VSD / Inverter or other non-linear devices.
  • Reduction of harmonics to 5-6%
  • Reduce cable heating and line losses.
  • Improve power factor and reduce system loss.
  • Minimise interference with other equipment.
  • Improved system voltage/current waveform.
  • Prevent nuisance tripping of fuse and circuit breakers.
  • Meets the IEEE519 Standard.


Active Harmonic Filters

  • Mainly used for group harmonic compensation at the main switchboard.
  • Reduction of harmonics to 5% or less.
  • Reactive current control.
  • Load side transient suppression.
  • Load side surge suppression. Reduction of supply sags and surges.
  • Improves electrical system efficiency.
  • Reduces operations and maintenance costs.
  • Meets the IEEE519 Standard.


Output (Load) side of the VSD (VFD)


Load Reactors

  • Also known as Motor Chokes, Load Filters & Inductors.
  • For use on the output of a VSD / Inverter or other non-linear devices.
  • Protect motors from long lead effects.
  • Reduce reflective currents.
  • Reduce Harmonic Distortion.
  • Reduce Surge Currents.
  • Reduce Motor Temperature.
  • Reduce Motor Audible Noise.


dV/dT FLTERS

  • dV/dT filters are designed to protect AC motors from the destructive effects of long lead peak voltages.
  • Increase bearing life and up-time.
  • Reduce common mode noise and currents.
  • Prevent voltage spikes from exceeding 1kV.
  • Reduction in motor peak voltages.
  • Protection of motor insulation.
  • Reduction of motor temperature.


Sine Wave Filters

  • In addition to protecting the motor, the sine-wave filter also provides protection for the VSD/inverter.
  • Unshielded motor cables can be used, lower project costs.
  • Motor operating life is increased.
  • Longer motor cables possible.
  • Significantly lower eddy current and stray flux losses.
  • Significant reduction of bearing currents.
  • Eliminate torque ripple.
  • Eliminate voltage wave reflection.
  • Reduces motor noise, vibration and heat.

 

Site Analysis

Power quality audits can be carried out on your site by Fuseco's expert Power Quality team to assess your Harmonic Mitigation needs. A report will be presented to you outlining the results and any recommendations on solutions that may be needed for your electrical system to comply with acceptable harmonic levels outlined in IEEE 519.

Request a Site Analysis

 

Solutions

Depending on the specific situation, there are a variety of products that are used to mitigate harmonics or reduce the effects of RFI. Fuseco's PQ Consultants are more than happy to assist in providing advice on your particular needs.

Contact our Technical Support Team

Power Quality Products


How can I find out more?

Schaffner have released an information booklet called "Basics in EMC & Power Quality".

Download booklet

Contact our Technical Support Team


We're here to help

Talk to an expert today.
Our friendly team of highly trained specialists will quickly assist you.

Get a quote technical support 1300 387 326

We promise to respond within 4 business hours (AEST).

Or you will receive $100 off your next purchase. Read how it works.

Lowest Price Guarantee

If you find a cheaper advertised price for an identical item, we will beat that price by 10%! How it works.

Reply in 4 Hours

You will receive $100 off your next purchase if we do not reply within 4 business hours (AEST).

Satisfaction Guarantee

If you are not satistfied with your purchase, return it. Read our 

Return of goods policy.

Top FAQs

Fuseco's Office and Primary Warehouse are located at: 

Unit 4 / 1-7 Friars Road, 

Moorabbin Vic 3189 

Melbourne, Australia 


Postal Address: 

PO Box 1425 Moorabbin Vic 3189 Melbourne, Australia

We'd love to hear from you! At Fuseco, rather than publish generic prices, we prefer to give you an individual quote. This ensures that we provide you with the best possible pricing to meet your needs.


The quickest way to place an order is to give our customer service team a call or send us an email. We promise to respond within 4 hours or you get $100 off your next order, however we usually respond within 1-2 hours to email enquiries. So go ahead and speak to us, we'd love to help you with your needs.

FUSES

  • $20 + GST
  • FIS (Free Into Store) for all orders over $100, excluding GST & freight (For account customers only)


ALL OTHER PRODUCTS

  • POA (Price On Application)
  • FOT (Customer nominates own carrier and accepts all charges)


Additional fees may apply for remote areas.


Freight details

In simple terms, harmonics are extra frequencies that when present in an electrical circuit, distort the AC sine wave. A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. For example, if the fundamental frequency is f, the harmonics have frequencies 2f, 3f, 4f... etc. 


Harmonic frequencies are equally spaced by the width of the fundamental frequency and can be found by repeatedly adding that frequency. In the case of the Australian electricity supply, the fundamental frequency is 50Hz. The frequencies of the harmonics are 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz and so on.


Learn more

For electrical systems to function in their intended manner without significant loss of performance or life, they require a supply of electricity that is of good quality. Good quality electrical power has the following characteristics: 

  • It must have a continuity of service (not be interrupted). 
  • It must have a very low Harmonic content. 
  • It must have a very low variation in the voltage magnitude. 
  • It must have very low transient voltages and currents. 

The term 'clean power' is used to describe electricity that is considered to be of good quality (see above) with particular reference to a very low harmonic content. Therefore, the term 'dirty power' is used to describe electricity that is considered to be of low quality (opposite to the above) with particular reference to a very high harmonic content. 


In Australia, our electricity is supplied in alternating current at a frequency of 50Hz. In alternating current (AC) the movement of electric charge periodically reverses direction. In direct current (DC), the flow of electric charge is only in one direction. 50Hz means that the AC has a frequency of 50 cycles per second. This is also known as the 'fundamental' frequency. AC is the form in which electricity is delivered to businesses and residences. Most electrical devices (such as motors) need clean electricity to function properly. This means that the electrical supply needs to be a clear sinusoidal wave.


Learn More

If you occasionally experience some unexplained occurrences such as flickering lights, alarms going off, or MCB's, MCCB's, RCD's and Earth Leakage devices tripping for no apparent reason, you are most likely experiencing harmonics in your electrical environment. Other signs are cables running hot, hot switchboards or overheating motors. If you are replacing your motor's bearings & insulation often, that's a strong indication of the presence of harmonics.

Learn more

Harmonics are very harmful within an electrical system and can have serious consequences. For example, the presence of harmonics reduces the life of equipment. It is possible that the investment that you made in your motors & drives will not be realised if they are damaged and need replacing before their expected life span. This can be very expensive. Harmonics cause things to run hot, which cause stress on the cables and equipment.


In the long term, this degrades an electrical system. The presence of harmonics will also mean that although you will get billed for the power that you are supplied, a large percentage of that power may be unusable. Harmonic mitigation is taking action to minimise the presence of harmonics in your electrical system and can achieve great cost savings.


Variable Speed Drives (also known as Variable Frequency Drives) are prolific creators of harmonics in electrical systems and as a result, most of the harmonic mitigation effort focuses on the input side and output side of a VFD.


Learn more

Depending on the specific situation, there are a variety of products that are used to mitigate harmonics. Fuseco's Power Quality Consultants can assist by conducting a site analysis or simply providing advice based on the details of the particular electrical system. Here is a brief summary of the product groups:


Line (input) side of the VSD

Device Features:

  • Line Reactors Simple & cost-effective method to reduce harmonics. Available in 3% & 5% versions.
  • Passive Harmonic Filters Significantly reduces harmonics from the VSD back out to the system and also improves true power factor.
  • Meets the IEEE519 Standard.
  • Active Harmonic Filters Active filters inject a 180 degree inverse current to nullify the harmonic content going back out to the system. They mitigate harmonics, compensate for voltage dips & can handle multiple VSD's relative to the reactive power required. Meets the IEEE519 Standard.

Load (output) side of the VSD

Device Features:

  • Load Reactors Simple & cost-effective method to reduce harmonics. Available in 3% & 5% versions.
  • dV/dT Filters dV/dT filters have been designed to limit peak voltage and increase voltage rise time. In addition to mitigating harmonics, the dV/dT filter also clips voltage spikes.
  • Sinewave Filters The ultimate load side harmonic mitigation product. Filters all harmonics, including reflective currents, eddy currents, common mode currents. Can be used for long cable runs (many kms). Stops the heating of cables. Great for the longevity of motors.

From the moment the AHF and SVG units were turned on our power factor issues were a thing of the past. At both sites our PF is now 0.99 on all phases all the time, the units react instantaneously to our fluctuating load and power factor and the result has been an excellent return on investment.

Brad Kilner

OPERATIONS MANAGER AT KILNER'S ENGINEERING

Technical Support

Our experts are all pre-eminent leaders in electrical products who provide excellent support in their areas of expertise.

Technical support

Talk to an expert

Our friendly team are highly trained product experts who really enjoy helping customers find what they need.

1300 387 326

call 1300 387 326

Enquire by email

We promise to respond within 4 business hours (AEST) or you will receive $100 off your next purchase.

Enquire now