Protective choke VINDEX 02,70/400-7-03,15/440

In particular, protective reactors eliminate the effect of higher harmonics on systems (capacitors) for reactive power compensation. Our standard offer includes VINDEX protection reactors in capacities from 1 to 60 kvar for voltages of 440, 525 V and dimming factors of 7 or 14%.

VINDEX reactors are characterised by their robust construction and comply with current standards. They are primarily intended for use in fused compensation switchgear with both classical and dynamic stage switching.

Protective reactors prevent overloading of capacitors due to higher harmonics and limit the switching current surge. This extends the life of the capacitors and increases the safety of the compensation equipment being operated.

The series connected protective inductor and capacitor form a resonant circuit that provides a restraint for higher frequencies, thus protecting the circuit from the development of dangerous resonances between the capacitor and the network.

The effect of harmonic distortion due to harmonics can cause: reduced life of power capacitors, unnecessary switching of circuit breakers and other protections, malfunction and damage to computers, drives, lighting circuits and other sensitive appliances. The inductance of the transformer together with the capacitors creates a so-called resonant circuit, which can be excited by the harmonic current produced by the load.

This resonant circuit has a resonant frequency and if there is a harmonic current near this frequency, the circuit is put into a resonant state where a high current flows through it.

This overloads the system and increases the voltage across the device which is connected in parallel.

VINDEX  inductors are designed for installation in environments with an ambient temperature of -5 to 40 °C.

The condition is that the daily average temperature does not exceed 35 °C. If the temperature and other required operating conditions are met, the temperature of the choke can be expected not to exceed 90 °C. The choke temperature can be monitored by means of an integrated temperature sensor. VINDEX  inductors are designed for indoor installation, the degree of protection is IP00, the permissible humidity is

max. 95 % non-condensing, forced cooling.

Protected compensation principle

Power factor compensation with tuned filtering is a method that eliminates the danger of a resonant condition by shifting the resonant frequency to lower values where no harmonic current is present. This is achieved by connecting a filtering inductor to the capacitors. Although the resulting circuit is still resonant, its resonant frequency is below the first harmonic present (damped). This ensures that a true resonant condition is not created. The capacitors of the protected section must be selected with this in mind, as they will have a higher voltage than the mains voltage when the inductor is connected in series.

The inductors must be selected with regard to inductance so that the required tuning frequency is obtained. The current carrying capacity must be sufficient to absorb harmonics.

Inductors are the most important heat source in the compensation cabinet, Proper selection of the cooling method is crucial.

Planning Table for Reactive Power Compensation – network 3×400/230 V AC, 50 Hz