The use of nonlinear loads such as power electronic based equipment and an electric furnace is now quite common. Such loads reduce the quality of the power of the network they are connected to. One of the parameters that best describes the power quality is harmonic distortion.
Harmonic distortions in the network cause the following:
In general, passive harmonic filters are used to prevent harmonic distortion in the mains. These filters consist of passive RLC components, that is, the resistor, the inductor, and the capacitor. The inductors (reactors) together with the capacitors in the harmonic filter form a resonance path. When the resonance frequency of the harmonic filter is adjusted appropriately, the harmonic currents due to nonlinear loads are prevented from entering the electric network.