Automatic Detuned Filter Capacitor Bank with reactor

Specifications

Power quality solution, Automatic Detuned Filter Capacitor Bank ( Harmonic 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.

Thyristor Switched Capacitor Banks (TSC)

Thyristor switched capacitor banks equipped with a fast control are designed to support the line voltage and to compensate the reactive power of the load. Thyristor switches make possible that a fast response is achieved without any mechanical wear, noise or excessive transient associated with contactor switching. A control signal can be brought from the compensated equipment and so it is achieved reactive power compensation almost without delay. All steps of the capacitor bank are switched on during one network period. 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.
 
Capacitor bank is chosen to be suitable for load according to the control system, compensation power and load switching. The compensated equipment can be symmetrical or unsymmetrical for main or phase voltage switched loads.