Capacitor Parallel-Resonance Point

Estimate the parallel-resonance frequency of a capacitor bank and check proximity to background harmonics (IEC 61642).

Inputs

System short-circuit capacity Sₖ MVA

Capacitor bank Q_c Mvar

Fundamental frequency Hz

Results

Note — f_r = f₀·√(Sₖ/Q_c). When the resonance falls near a characteristic harmonic (5th, 7th, 11th, 13th) the harmonic current/voltage is amplified. De-tune with a reactor (e.g. 7% for 5th) and verify with the network study and a certified engineer.