HARMONICS : Harmonics are unwanted frequencies which superimposed on the fundamental waveform creating a distorted wave form. LINEAR AND NON LINEAR LOADS : linear load : the relationship between the voltage and current waveforms are sinusoidal and the current at any time is proportional to the voltage (Ohm's law). non - linear load : the current isn't proportional to the voltage and it fluctuates based on the alternating load impedance. HOW HARMONICS ARE GENERATED : Harmonics are created by electronic equipment with nonlinear loads drawing in current in abrupt short pulses. The short pulses cause distorted current waveforms, which in turn cause harmonic currents to flow back into other parts of the power system . Then it makes the pure sine wave into distrocted wave form, after this the distrocted waveform was flowed into any other load means it creat some fluctuation in load side. DISADVANTAGES : Due to harmonics load produce