Detuned Reactors prevent harmonic amplification caused due to RESONANCE and avoid the risk of overloading capacitors, thereby significantly reducing voltage and current harmonic distortion in the network. All connected equipment, and even remote substations are subject to voltage fluctuations which may result in equipment malfunction or failure. To avoid this problem, it is common to insert reactors in series with capacitor banks.
The reactor also by its nature will safeguard capacitor and associated switch gears against switching inrush, which other may damage capacitors, circuit breakers and contactors.
Why use Detuned reactor?
Presence of Harmonic distortion due to the non-linear loads within the network or due to import of harmonic from grid or power source will increases the current flowing through capacitors as the capacitive reactance is inversely proportional to the frequency , consequently capacitors will be subjected to over load. The over load on capacitors can cause premature failure in capacitor due to increased voltage and thermal stress on dielectric.
On the other hand, the inductive reactance XL of a Reactor is directly proportional to frequency: The magnitude of inductive reactance will increase with high frequency harmonics thus blocking the harmonic current. Hence, use of detuned reactor in series with capacitor will offer higher impedance for harmonics, thus eliminating risk of over load in capacitors.
The inductance value of detuned reactor is selected such that the resonance frequency is less than 90% of dominant harmonic in the spectrum. For example: if 5thharmonic is dominant in the spectrum, any series LC circuit having resonance frequency 90% of 250Hz (for 50Hz system), i.e. if the natural resonance frequency of LC is less than 225Hz, it is categorized as detuned filters or detuned capacitors.
What are the benefits of using a Detuned Reactor?
The typical benefits of a detuned reactors are as follows:
- It eliminates harmonic amplification
- It enhances the life of capacitors by reducing voltage and thermal stress due to harmonics.
- Prevents the constant nuisance of input fuse blowing or circuit breaker tripping
- Reduces over heating of the transformer, busbars, cables, switchgear etc caused due to harmonic amplification.
- Reduces the harmonic current in the electrical supply system
- Addresses the harmonic problems created by non-linear loads.
- Improves Power Factor in harmonic rich environment.