System for providing assured power to a critical load

Abstract

A power system ( ) is provided for economically supplying uninterrupted electrical power to one or more critical loads ( ). One or more fuel cell power plants ( ) provide one substantially continuous source of power, and a utility grid ( ) provides another source of power. The fuel cell power plants ( ) are adapted to be, and are, normally substantially continuously connected and providing power to, the critical load(s) ( ). A rapidly-acting static switch ( ) selectively connects and disconnects the grid power supply ( ) to the critical load(s) ( ) and with the fuel cell power plant(s) ( ). A switch controller ( ) controls the state of the static switch ( ) to connect the grid power source ( ) with the critical load(s) ( ) and the fuel cell power plant(s) ( ) during normal operation of the grid ( ), and to rapidly (less than 4 ms) disconnect the grid power source ( ) from the load(s) ( ) and fuel cell power plant(s) ( ) when operation of the grid ( ) deviates from normal beyond a limit.