Damping reactors connected in series with shunt capacitors to limit the inrush current when capacitor is energized, limit the outrush current during closing faults or adjacent capacitor switching and/or to detune capacitor banks in order to avoid resonance with the power system.

Damping reactors under normal operation, the current flowing through the reactor is composed of a power frequency current and a superimposed harmonic current. For damping reactors, the power frequency current is usually much greater than the harmonic current whereas for filter reactors the specific application will determine the ratio of the two current components.

Capacitor Inrush current damping reactors are generally used in series with the capacitor bank either in the line or neutral side forZ limiting the switching inrush current.
The short circuit withstand ability of the reactor is designed depending whether the reactor is placed on line or neutral side of the capacitor bank. They are extensively used with MV and HV capacitor banks.