Westinghouse Electric Corporation

Francesco Lardi

Leaman B Podolsky

Uri G Ronnen

Gary W Berkebile

Donald J Jones

William D Ghrist, Iii

Guy E Davis

A system and method for operating a turbine power plant, wherein a demand signal based upon load or total turbine steam flow required for a predetermined level of operation controls the value of individual signals representative of valve position for respective steam inlet valves in the single and sequential mode of operation, is disclosed. Each individual valve position signal, which is representative of a selected portion of the total demand signal, is dynamically calculated to reflect the effect of the pressure drop across the nozzles, and to correct for the number of inlet nozzles, associated with each valve. The total demand signal is modified in accordance with actual throttle pressure over a period of time that is dependent on the amount of throttle pressure change.

System and method for controlling a turbine power plant in the single

A throttle valve test system for a large steam turbine functions in a turbine control system to provide throttle and governor valve test operations. The control system operates with a valve management capability to provide for pre-test governor valve mode transfer when desired, and it automatically generates feedforward valve position demand signals during and after valve tests to satisfy test and load control requirements and to provide smooth transition from valve test status to normal single or sequential governor valve operation. A digital computer is included in the control system to provide control and test functions in the generation of the valve position demand signals.

Steam turbine power plant having improved testing method and system for

An electric power plant including a steam generator and a steam turbine is operated by a control system including two redundant digital computers. Switching circuitry is provided for coupling one of the computers through interface equipment to the steam generator and the turbine and a generator according to programmed computer control. A data link is established between the computers to transfer manual/automatic status and other needed data from the control computer to the standby computer. A system is provided for detecting when certain hardware and software malfunctions have occurred and for responsively transferring control to the standby computer. The standby computer is tracked to the control computer so that control computer transfer can be made reliably without disturbing the electric power generation process. The turbine control includes a load control loop which is implemented with computer operations. Load control is also implemented in load control loops for the steam generator by means of computer operations. Computer transfers are executed smoothly in the load control mode at substantially any load level of operation.

Wide load range system for transferring turbine or plant operation

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.

System for operating a steam turbine with improved speed channel failure

A digital electrohydraulic steam turbine control system that generates a feedforward total steam flow demand signal to position the governor valves singly or sequentially in accordance with a dynamic nonlinear representation of steam flow vs. valve lift position having provision for testing the throttle valves while the turbine is operating in either the single or sequential mode and without effectively disturbing the load on the turbine and without the necessity of turbine operational feedback loops in service, is disclosed. Decremental and incremental flow changes for each of the governor valves in the test path and the non-test path, respectively, are calculated iteratives in accordance with a non-linear valve flow vs. valve lift position characterization for the total steam flow to the turbine. Subsequent to the test, the control valves are repositioned to the normal pretest sequential or operating mode by incrementally changing the flow of all the valves toward the normal operating mode position so that the net total flow is unchanged.

Steam turbine valve positioning system having throttle valve test

A protection system is provided for a turbine plant to avoid double shock or similar rotor blade operation. A digital computer controller detects excessive blade loading conditions on the basis of governor valve positions and effects bumpless mode transfer from sequential valve operation to single valve operation to avoid excessive blade loading.

Steam turbine blade protection system and method especially for electric

A combined digital computer/analog control system for operating a boiling water reactor steam turbine power plant, wherein the digital computer provides a throttle pressure setpoint, speed error and load demand for controlling the plant depending upon the operational states of the system, is disclosed. The analog portion of the system also controls the plant in cooperation with the digital computer for certain operational states and conditions when the digital computer is in operation; and the analog system alone controls the plant when the digital computer is out of service. The transfer between such control is effected depending upon the operational states of the system and certain of the components therein. The system also includes in the digital computer portion, the provision for preventing a load demand which is outside the limits of the reactor circulation system when the reactor is in a state of automatic operation.

System for operating a boiling water reactor steam turbine plant with a

A combined digital computer/analog control system for operating a boiling water reactor-steam turbine-power plant wherein one of two analog throttle pressure controllers is used for controlling the inlet and bypass valves. One of the pressure controllers is biased to provide a higher signal than the other; and such nonbiased controller is the one selected to control the valves. Each controller includes a pressure transducer, a summing device and amplifier, and a lead/lag circuit together with the appropriate power supply. A failure detection system is used to switch the controllers from automatic to manual when a predetermined combination of controller components becomes defective. Also, such system is so organized that a transducer failure for one controller causes the other controller to assume control regardless of whether such failure results in a higher or lower than proper signal.

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Pittsburgh, PA, United States of America

Francesco Lardi