System for operating a steam turbine with improved speed channel failure detection

摘要

A digital computer control system for operating a steam turbine in an electric power plant is disclosed. Under automatic control, the digital computer calculates a steam flow demand signal for positioning the steam inlet valves. A speed feedback loop is used to modify the steam flow demand signal as required to maintain the desired speed. The speed loop selects a first or second of three independently generated speed signals depending on the difference between the three speed signals. The first speed signal is a digital signal; and the second is an analog signal, which is converted to a digital signal. The digital signal consists of a fine and a coarse speed signal which is selected in accordance with turbine speed to constitute the first generated speed signal.