Detuned reactors

The harmonic reactors connected to the capacitors form a series resonant circuit (usually 189 Hz) which prevents unwanted resonance and also acts as a wideband filter. This protects the individual components of the compensation system from overload. Reactors are characterized by high linearity and low losses. It is usually recommended to use reactors with a THD voltage distortion higher than 3%.

Voltage: 230 - 1000 VAC
Power: 1 - 100 kvar
Frequency: 50/60 Hz
Attenuation: 5.67%, 7%, 14%

Download catalogue sheet Guide for matching of reactors and capacitors


Frequent use of power electronic devices with nonlinear loads leads to harmonic distortion in electrical system. This nonsinusoidal load causes increase of effective current of power capacitor and other components of the system as well as the posibility of capacitor resonance with other inductive loads.

Finally it may lead to problems or even failures in the installation. The solution is to use detuning (filtering) reactors, which creates a series resonant circuit with power capacitors. This detuned system prevents the installation from resonance effect and also acts as a filter for higher harmonic content. Usually there is recommended to use detuning reactors for the total voltage distortion THD-U higher than 3 %.


Detuning reactors are produced from high grade, low loss transformer sheets, with winding either from copper wire or aluminium band. Iron core is designed with multi air gap to meet high current linearity and low thermal losses. They are impregnated with high quality epoxy resin to ensure good insulation, low noise and long lifetime. Reactors are equipped with thermal protection to prevent overheating.

Reactors with lower rated power are designed with copper wire and outlets via terminal block or cable lug. Higher power rated reactors are produced from aluminium band with outlets as aluminium bars (copper outlets are possible on request).