SUBSTATION AUTOMATION
HARMONIC FILTER REACTOR
The harmonic filters essentially consist of reactors and capacitors, & are usually installed close to the source of harmonics in order to provide low impedance path for the harmonic currents.
A parallel resonant filter has a high impedance that blocks for currents of a certain frequency, while a series resonant filter has a low impedance that leads away currents of a certain frequency from parts of the power system where are undesired.
If fine tuning of the filter is required, the filter reactor may be equipped with taps for inductance adjustment.
When lower “Q” factor is desired, it can be achieved either by providing the resistor in filter circuit OR the “Q” factor of the reactor can be reduced by providing loss making ring, popularly known as Diminished-‘Q’ ring. Diminished –‘Q’ ring provides economical solution & requires lower space.
