Westinghouse Electric Corporation

Alan T Heltsley

William E Zitelli

A turbine speed control system comprising a pair of concurrently operable electronic microprocessor-based controllers which are coupled together by a data link to functionally cooperate in controlling turbine acceleration primarily during start-up operations in accordance with a set of predetermined measured and calculated turbine conditions. One controller is operative to control the speed of the turbine at selected accelerations from turning gear to a predetermined speed value. This same controller monitors a plurality of temperature differences from preselected regions of the turbine and inhibits turbine acceleration in accordance with an out-of-limit temperature condition associated therewith. In addition, the one controller is further operative to selectively override the turbine speed hold initiated by an out-of-limit temperature condition, the override permitting the one controller to proceed with controlling the speed of the turbine at a desired acceleration. The other controller is selectively operative to govern the turbine acceleration as controlled by the one controller based on calculated present and anticipated rotor stresses which are derived concurrently with the speed control operations of the one controller. A turbine speed hold may be initiated by either a detected differential temperature out-of-limit condition or a detected calculated rotor stress limit condition. In either case, the one controller is further operative to detect if the speed hold occurs in one of a number of predetermined critical speed zones and to adjust the turbine speed outside of the zone in which the speed hold occurs.

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Chester Upland, PA, United States of America

Alan T Heltsley