Apparatus and method for dynamic voltage restoration of utility distribution networks

摘要

A system and method is provided compensating utility distribution line transients such as voltage sags in a dynamic manner, by inserting a voltage signal in series with the distribution signal having a magnitude and phase to effectively cancel out the voltage deviation caused by a network disturbance. An energy storage device such as a storage capacitor is used to provide energy to an inverter circuit which is controlled to generate the series-inserted signal. Preferably a converter such as a chopper is utilized between the storage element and the inverter, to provide a constant dc input to the inverter. A controller generates a corrective error signal based upon the deviation between the utility supply voltage as affected by the disturbance, and the nominal ideal voltage signal, and adjusts the insertion voltage so as to optimize real power delivery to the utility distribution line.