Synchronous Closing Control for Shunt Capacitors

The traditional approach to switching surge control assumes that switching operations may take place at the worst possible time (worst "point of wave"), and modifies circuit parameters to reduce surges. This is normally accomplished with current limiting inductors or by dividing switching operations into two (or more) stages; e.g., for closing, the first stage inserts a resistor and the second stage shorts that resistor. An alternative approach to reducing energizing transients is to time the switching device to close at the best possible time (when voltage across the switch is zero) rather than altering the circuit parameters.