When the capacitor is connected in series with a 6% reactor (De-tuned Filter), the tuning point will fall at 4.08 times. Although in the power system, when a Detuned Filter is added, there will still be a resonance point (as shown on the left), but at this time the resonance point can be controlled to fall below 4.08.
In a general three-phase load, the harmonic components will start from the 5th order (5,7,9,11,13,17,19...), there will be no harmonics below the 5th order, so even if there is a resonance point below the 4.08th order , and no harmonic components will be amplified. However, if there are many single-phase harmonic loads in the power system, there will be 3rd harmonics. In this case, it is recommended that the capacitor be connected in series with a 13%, 14% or 15% reactor.
