Harmonics

Some harmonics (the third in particular) can generate high currents in the neutral. They are also electronically noisy and liable to give problems to sensitive equipment that may be on the line. There would be some energy losses, but that aspect is comparatively minor, so far as my layman's understanding goes.

Thanks......

Yes, due to harmonics the amplitude of current increases, but could you quantify or atleast describe energy losses because of harmonics

For any current flowing in a conductor, there is an energy dissipation equal to I²R. In a heater, this would be useful, but otherwise it is (at least sort of) a parasitic loss, which usually is relatively small in the overall scheme of things. Limiting this loss will save a little bit of energy. The fact of saving a small amount of energy is sometimes blown out of proportion in various power factor or harmonic correction schemes (and scams), which can be expensive for little gain. Cleaning up harmonics can be good for other reasons, though, such as avoiding damage to sensitive components. (Or burning up undersized neutral conductors.) Let me emphasize again that this is a simplified layman's view; I am not familiar with all the calculations.

There are other forum members who can describe this better, and with luck we will hear from them.

Thank you

Could you send me the other forum address

This same forum, namely CR4.

I tried to add to the foregoing, but ran out of time.

This same forum, namely CR4. JRaef, msamad and kvsridhar, to name three, are highly professional, as are TonyS and PWSlack. In electronics, I should also mention Winfield Hill, redfred, and JohnDG. No doubt I am missing a few others, for which I apologize.

Compared to those folks, I am a layman, but I try to translate theory into lay terms and analogies that fellow laypersons can relate to. (I am also a prankster, so bring along a salt shaker.)

Going purely on experience I installed a sub distribution board fed by a 185mm 3½ core feeder cable.

The loading was supposed to be balanced, but as per usual red and blue phases took most of the load. The neutral conductor was near glowing.

Unbalanced loads due to the third harmonic can cause havoc.

Thanks..... But can you suggest me practically the meaning of 3rd,5th & 7th harmonics, where it develops and what is its effect on equipment, and how does it is related to more energy consumption

Yep. Google "harmonics". Lots of people can.