Power Factor correction with Thyristor?

[Le Minh Hoang Hac]

Hi guys, this is bugging me for days now but does anyone know how power factor correction work with thyristor switched capacitor bank (TSC)? I did some research before hands and it turns out that manufacturers use FFT in their thyristor controllers to switch the capacitor banks. I'm aware of the fact that FFT can be used to measure power factor simply by taking cosine of the subtraction between voltage phase and current phase. How can they know how many capacitor banks to be switched on by the thyristors?

 

[chuckey]

If they know the voltage phase and the current phase, they know their amplitude, so they can do the maths , come to an answer, and select the capacitors that are nearest the calculated value.
Frank