The nonlinear currents generated by the massive use of modern power and electric equipment are impacting the  power grid and aggravate its pollution in the harmonic form, cause overload failures to capacitors, transformers  and transmission devices and generate serious interference to measuring, transmitting and calculating devices;  in addition, resonance and voltage distortions may also result in power supply accidents, Series reactors could  effectively improve or avoid such problems. After installing the capacitor and reactor in series, the resonance  frequency is lower than the minimum of the system (usually 5th and 7th waves), so that compatibility is showed  under power frequency and power factor is improved; meanwhile, there is no need to worry about the amplification of harmonic wave. With satisfactory impedance matching. the capacitor bank could absorb 30% to 60% of  the harmonic currents (5th harmonic wave, for example).