Field experience with a digital relay for synchronous generators

The authors provide the specifications and characteristics of a digital relay for synchronous generators that performs seven protection functions. They also present preliminary performance results, following installation on one of the units at the Carillon generating station in the Hydro-Quebec power system. During a period of four months, although no fault was recorded in the unit, the relay watchdog system and self-monitoring routines functioned flawlessly. The prototype provides the basis for a new standard protection system for Hydro-Quebec´s future and existing generating stations