Dr.InPhase Edu Series – Active Harmonic Filter Vs Detuned Filters

Hello Readers,

As part of my educational series today we are going to try to understand the different kinds of Harmonic filters namely the Active Harmonic Filter Vs Detuned Filters.

Educational Series Dr.InPhase

The objectives of Active Harmonic Filter and Detuned Filters are not the same and also not so different. It all depends on requirement specific.

When to use Active Harmonic Filter or Detuned Filter?

Industries operating with huge non-linear loads, ex:  manufacturing plants like steel, automobiles, cement, textile, refineries, Data Centers, Multi Specialty Hospitals, Shopping Malls and all other processing industries.


Why do we need AHF or DF?

Industries operating with more inductive loads and drive based loads have tendency to generate more  Harmonics and consume more Reactive Power . This increase in harmonics and reactive power would result in;


What are Harmonics and why it has to be mitigated ?

Harmonics are sinusoidal voltage or current waveforms oscillating at a frequency which are integer multiple of fundamental operating frequency (50Hz or 60Hz).

When an ideal sinusoidal voltage is applied to the linear loads, they absorb power as the way it is supplied, but in case of non-linear loads which are connected through converters will draw the current inexplicably with voltage, as the current is drawn w.r.t switching frequency (frequency = 1 / Time ) of the converter. This change in current w.r.t time leads to current harmonics and also due to momentous impedance between the power supply and the load, current harmonics will also raise the harmonics in voltage waveform. Increase in harmonics would cause neutral overheating, failures with electronic components, overloading of capacitors, heating of transformers and etc.

What is Reactive Power and why it has to be minimized?

Apparent Power (KVA) = Real Power (KW) + Reactive Power (KVAR)

Reactive power is the magnetizing power for motors to operate, but however it is not a useful power. i.e. work done by reactive power always equals zero.  So, higher the reactive power equals higher electric billing under KVAh scheme. Reducing reactive power implies increase in power factor and reduced electric billing.

How to minimize reactive power and mitigate  harmonics ?

Active Harmonic Filter are preferred when the requirement is for both power factor improvement and harmonic mitigation. Whereas Detuned filters can only achieve in improving power factor i.e. minimizing reactive power.

detuned filter


Comparison Chart on non-linear loads without filters / with Detuned Filter / with Active Harmonic Filter


How Active Harmonic Filter mitigates harmonics and minimize reactive power ?

Dr.Inphase Interesting

Interesting right that is what will be discussed in detail in our next Edu series. See you until then


At InPhase Power we are very serious about improving the power quality of the nation. Our products provide unmatched improvement in Power Quality by effectively curbing harmonics and maintaining steady power factor. Explore our Products Active Harmonic Filter(IPC150-AHF) and STATCOM (IPC150-SCOM) to find how they can improve your power quality.

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