Understanding your Harmonics #Harmonics #Powerquality #Electrical

Harmonics is the "Multiple Integer of your fundamental frequency"

Simple Right.!

In India we use 50Hz as fundamental, 60 Hz for US, Canada, Brazil, Columbia, Cuba, Liberia, Mexico ...

And our power is RYB Phase, which is 120 degrees apart from each other. (Let us denote them as ABC now on)

Here, what actually happens is, Let us say 50Hz is "x"

Second Order Harmonic is (2*x) = 100 Hz

Third Order Harmonic is (3*x) = 150 Hz

Now, these odd orders we will see in detail which are usually the problematic ones for majority of the industries

Harmonics such as the 7th, which “rotate” with the same sequence as the fundamental, are called positive sequence.

Harmonics such as the 5th, which “rotate” in the opposite sequence as the fundamental, are called negative sequence.

However, Triplen harmonics (3rd and 9th shown in this table) which don’t “rotate” at all because they’re in phase with each other, are called zero sequence.

What actually happens is Positive and Negative Sequence help to compensate for each other, where as triplen harmonics get added up.

These zero-sequence harmonic currents can only occur when nonlinear loads are connected phase-to-neutral in a three-phase, four-wire distribution system. Although positive- and negative-sequence harmonic currents have always existed in industrial power conversion systems, these nonlinear loads are always connected phase-to-phase. 

The presence of harmonics does not mean that the factory or office cannot run properly. Like other power quality phenomena, it depends on the “stiffness” of the power distribution system and the exposure of the equipment when operating in the presence of the harmonics. One factory may be the source of high harmonics but be able to operate properly. This harmonic component is often carried back onto the electric utility distribution system, and may affect neighboring facilities on the same system which are more susceptible.

Let us go deep into understanding our harmonics which is part of our day to day operation.

How do we generate harmonics I will keep it for my next writing as this will get boring after a point.! :-)

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