Harmonics overview

Why harmonics problem?    3 types of solutions!      How to make a choice ?     Any software tools ?

Typical distorted current waveforms

Typical distorted current waveforms

The wide spread use of power electronic devices in power networks is due to their multiple functions: compensation, protection, adaptation and transformation of the electric energy. However, because of their switching components, power electronic converters generate current and voltage harmonics which may cause measurements, stability and control problems.

To avoid the harmonic distortion, it is necessary to equip the installation with filtering systems.

There are 3 types of filters: passive filters, active filters and hybrid.

  • The passive filters represent a LC circuit tuned to a harmonic order close to the order to be eliminated. Several parallel-connected branches of filters can be used if a significant reduction in the distortion of a number of harmonic orders is required.
  • The active filters represent power electronics devices, which generate and inject harmonics drawn in an opposite phase such that the line current Is remains sinusoidal.
  • The hybrid filters are a combination from active filters and passive filters.

Before to reduce the harmonics distortion, the installation of power quality meter devices is recommended. This is the first step in gaining control over harmonic pollution!

Measurements allow to obtain an overall idea on distribution-network status and to choose the solution for the reducing of the harmonics distortion.

  • Normally active filters are used for highly polluted networks.
  • Passive filters are usually used in less polluted networks, where limited number of harmonics are responsible for the harmonics distortion.

In industry, very often the capacitor banks are combined with harmonic filters, as they are highly sensitive to the harmonic disturbances.

At my knowledge, there is no tool or software that can be used for the choice of the harmonic filters, mainly measurements are used and individual solutions are proposed.

In contrary, several software exist for sizing the capacitor banks…. Like

  • Simaris,
  • Ecodial,
  • ID Spec,
  • DocWin,
  • ElectricalSolutions software and so on…

Christian Petrov


  • what is harmonic, what is called harmonic exactly? ( is it the same as we have in music if yes, go on >> )
    can we say in AC, zero crossing of current ( or voltage ) can cause harmonics ( some repeated waves with different frequencies?
    if yes, so what is harmonic in DC which we don’t have any zero crossing!?
    I really want to know the concept of harmonic ( or harmonics!! or even harmony, which one ? ) in Electrical Engineering.

    I am electrical engineer but i still have problem in this ( and many more … )


  • hello..i really need your help..i’m doing my project..n if can i want to know how to design circuit of active power filter that design to eliminates harmonics.The inverter is power switches which is IGBT.I also dont know how to connect and design the position and control the IGBT..Thank you..I really need your help as soon as possible

  • i want a solution in 600 hp dc moter @ 650 rpm , voltage – 500, same maoter not running with 1500kva genrater but running with stae powe. can we use harmonic filters to rectefy this problem.

  • hello…! recently i do the my project on harmonic reduction. i want to know how to designe harmonic filter if harmonic produce due to variable frquency drive, whethar i use matlab software????
    and also how i calculate the harmonic distortion in the supply line?

  • I really need ur help..i am my project on to suppress harmonic resonances in distribution power system.I want to know how to design it..Thank you..I really need ur help as soon as possible.

  • what is low pass filter? and how to make it as a project base?
    give me an idea about this….

  • i need a generalised simulink model of a sigle phase active filter with its pq theory control device.

  • pls i nid a comprehensive circuit diagram of both active and passive filter used for harmonics effect. thanks, slog

Leave a Comment