Method and system for testing an overspeed protection system of a powerplant

Embodiments of the present invention have the technical effect of automatically testing an overspeed protection system associated with multiple powerplant machines of a powerplant (100). An embodiment of the present invention may automatically test the overspeed protection system while at least one of the powerplant machines is in the process of shutting down (300). Another embodiment of the present invention may automatically test the overspeed protection system by adjusting the speed of a shaft (137) while at least one of the powerplant machines (105,160) operates at full-speed-no-load.