Power system harmonics are unwanted components in supply signal which are integer multiples of fundamental frequency components. These harmonics are created by the non-liner devices presented in the power system network or due to some lighting surges. If this harmonics are high and out of tolerable limit creates an unwanted oscillations and distortions in voltage and current signals.

The effects of the harmonic currents on Transformer

- Additional copper losses due to harmonic currents
- Increased core losses
- Increased electro magnetic interference with communication circuits.

The effect of harmonic voltages of the transformer

- Increased dielectric stress on insulation
- Electro static interference with communication circuits.
- Resonance between winding reactance and feeder capacitance.

Due to this there will be losses in the transformer which significantly influences the power system operation. The effect of harmonics on the various losses are explained below

Effect of Voltage Harmonics on transformer