For many years now, power factor correction has been one of the first steps to improving the energy efficiency of installations. Since their beginnings, compensation techniques have grown and developed over the years, adapting to new needs (basically the types of loads that must be compensated) and to new technologies that have become available.
At first, the most common compensation technique was to use capacitor banks with contactor operation. This compensation system is optimal for balanced systems and to compensate loads with connection and disconnection rates that are not too fast, on the order of seconds, and it is currently the most common system in most installations despite increasing numbers of unbalanced installations.
The passage of time and the growing use of more dynamic loads in many installations has led to the emergence of a new technique: the use of static contactors (solid-state relays or thyristors) to operate the capacitors in a capacitor bank.
More information in our technical article about the 晶闸管电容柜：实例