Nokian Passive Filter

Power transmission and distribution systems are designed to operate with sinusoidal voltage and current waveforms at a constant frequency. However, when nonlinear loads - such as thyristor drives, converters and arc furnaces - are connected to the system, excessive harmonic currents are generated, and this causes both current and voltage distortion. Power factor correction by means of conventional capacitor banks is not possible in systems affected by harmonics. This is because the harmonic-currents are amplified in the parallel resonant circuit formed by the capacitor and the network. As a result current and voltage distortion are further increased.

When harmonics are presented in the system, power factor correction should be implemented by means of automatic capacitor banks with blocking reactors. Each step of the bank consists of a capacitor unit with a blocking reactor. These form a series resonant circuit tuned to a frequency below that of the lowest harmonic.

detune