Rule-based approach to load transfer to alternate supplies based on the phase of the residual voltage on the disconnected busbar

Transfer techniques and a rule-based approach to an in-phase load transfer scheme for secondary selective substations are developed. The transfer scheme, with its developed transfer techniques and rule based algorithm, integrates into a microcontroller-based in-phase transfer controller to maintain the continuity of power supply to process loads. The rule sets initiating conditions, blocking transfer criteria, load shedding schedules and possible events. It provides a safe and successful bus transfer system. Operations of the load transfer scheme with simulated load conditions have been tested through the the in-phase transfer controller. The results of computer simulation and test measurements show that the load transfer operation is performed successfully. The inrush current, transient torque and service reliability can also be improved by using this transfer scheme