Mitigation of voltage violations caused by the disconnection of distributed generation by using a centralized control of the step-voltage regulator

Temporary faults can isolate a portion of the distribution system, causing momentary electrical islands due to the opening of reclosers. When an island is formed, the anti-islanding protection disconnects all the distributed generators from the grid. After the temporary fault has been eliminated and the reclosing operation is done, the isolated portion is reconnected to the grid and all the loads are energized simultaneously, however, the distributed generators must remain disconnected for a specified period of time. This sudden load-generation imbalance can origin power quality problems such as short duration voltage variations within the distributed system. In this paper, the effects of the anti-islanding protection operation on the power quality are explored. A new method to mitigate the voltage problems by using centralized control of the step-voltage regulator taps is investigated. The new method has successfully diminished power quality voltage problems after the disconnection of the distributed generators.