It is quite clear that the presence of harmonic will increase the kWh consumption in the network.
The excess energy consumption is due to the following:
a) Losses in the conductors/switchgears due to Skin effect.
b) Losses in transformers / reactors (Iron core) due to increased:
– Magnetostriction (Sound loss – you can hear more humming noise when harmonic is more).
– Core loss.
c) Higher energy consumption in Rotating machines such as Induction motors, Generators due to Negative torque induced in the rotor winding when Negative sequence harmonic are present.
Other stray losses..
The problem is in quantifying or making the losses tangible. To do that it is important to have detailed analysis of each of the equipment in the network, which may be very tedious job.
In most of the cases, even if we quantify the losses, and if we install any harmonic filtering solution such as passive or active filters, the loss saved due to reduction of harmonic and internal losses in the filters may be almost equal.