| 摘要 |
PURPOSE:To improve reliability by using remaining detectors and speed detectors of the secondary turbine to control a turbine when a predetermined number or more of multiple speed detectors provided on the primary turbine of a cross compound type turbine fail. CONSTITUTION:Three speed detectors DP1-DP3 are provided on the primary turbine, two speed detectors DS1, DS2 for speed-governing are provided on the secondary turbine, and signals from individual detectors are inputted to a majority logic circuit ML via a speed measuring circuit PC. The majority logic circuit ML gives priority to individual selection function circuits SEL1-3, and if one or more speed detection signals are abnormal, signals from the speed detectors of the secondary turbine passing through individual selection function circuits SEL4, 5 are added in sequence, and three signals are arranged in the order of size. The presence of abnormality is checked based on the deviation among these signals, and a normal signal is used to control the turbine. |
