초록 ▼

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

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.

대표청구항 ▼

An electric power generating system having a steam turbine, a steam generator for supplying steam to the turbine, an electric generator rotatable by said turbine and adapted to be connected to an electrical load, said system comprising: valve means for controlling the flow of steam from the steam ge

An electric power generating system having a steam turbine, a steam generator for supplying steam to the turbine, an electric generator rotatable by said turbine and adapted to be connected to an electrical load, said system comprising: valve means for controlling the flow of steam from the steam generator to the turbine to control the operation of the turbine; means to generate an electrical signal representative of steam flow demand; valve actuating means governed by the steam flow demand signal to control the oPeration of the valve means; speed sensing means for sensing at least the magnitude of the turbine speed, said speed sensing means including means to generate at least first, second, and third independent electrical signals representative of turbine speed; calculating means governed by the generated speed signals to at times control the steam flow demand signal in accordance with the selected first or second speed signal, said calculating means including sequence controlling means having the following components: (a) means for comparing said first, second, and third speed signals, (b) means governed by the comparison means to determine whether said first, second, and third speed signals differ from each other by a predetermined magnitude, (c) selection means governed by the determining means to select the first speed signal in response to a first condition where said first and second signals differ from each other by an amount less than said predetermined magnitude, or where said first signal differs from the third signal by an amount less than said predetermined magnitude while the second and third signals differ from each other by at least said predetermined magnitude, and to select the second speed signal in response to a second condition where the second and third signals differ from each other by an amount less than said predetermined magnitude while the first and second signals differ from each other by at least said predetermined magnitude; and (d) means to switch to the selected speed signal in response to a change between the first condition and the second condition.