Harmonic, triplen harmonic, why it is existing and what its effect.

Dear all hands

As ordinary people maybe we didn’t bother what is it harmonic? But for some one whom work in utility company, harmonic may be a big concern.

In normal condition harmonic current caused by non linear load, such of switching device (SMPS), energy saving lamp.

What it is non linear load? Non linear load is a electrical load that didnot draw sinusoidal current when a sinusoidal voltage applied on it. R,L,C is linear load but switching device isn’t.

Figure above (a tree phase rectifier with six pulse configuration) show a non linear load that draws non sinusoid current (in this case in form rectangular wave).

Harmonic current effect

Harmonic current cause many detoration effects:

1. voltage distortion

2. increase in iron losses

3. overheating

4. disturbance in instrumentation

Triplen harmonic

Triple harmonic in electrical engineering have more crucial effect because is exist in zero sequence so this triplen harmonic didn’t eliminate each other. As we now zero sequence fasor has same direction and same tangent, like figure below(but for more detailed explanation about phase sequence component you can read this text book or this):

Clearly from figure above that zero sequence just only differ in their magnitude, they can’t eliminate each other.

What its triplen harmonic? Triplen harmonic is an harmonic component that exist in zero phase sequence, below is table of harmonic order in phase sequence.

From figure above, triplen harmonic is in order 3, 6,9,12etc; and its clear where is the name come from.