Abstract: A multi-stage compression system in which gases compressed by a pair of first-stage compressors are compressed by subsequent compressors connected to the first-stage compressors in series includes a valve control unit configured to output open/close signals for opening/closing valves for adjusting flow rates of gases flowing into the first-stage compressors provided at inlet sides of the first-stage compressors. The valve control unit outputs an open/close signal having a difference less than or equal to a predetermined value with respect to a degree of opening of the valve before malfunction determination as the open/close signal until a malfunction is eliminated after the determination of the malfunction in which one of the valves does not have a degree of opening according to the open/close signal.

Abstract: Specific operation is executable in a Rankine-cycle power-generating apparatus. In the Rankine-cycle power-generating apparatus, a) in the specific operation, the control device adjusts the degree of opening of the opening/closing device so that the direct-current electric power absorbed by the electric power absorber approaches first electric power, or b) in the specific operation, the degree of opening of the opening/closing device is increased to the predetermined intermediate degree of opening so that the direct-current electric power absorbed by the electric power absorber falls within a predetermined range.

Abstract: A speed controller generates a speed control output signal based on an output target value and a detected speed of a steam turbine, an extraction pressure controller generates an extraction pressure control output signal based on an extraction flow rate target value and a detected extraction pressure of the steam turbine, and when operation signals of a governor valve and an extraction control valve are generated with reference to an extraction map for deriving opening degrees of the valves at an operation point determined depending on the signals, the extraction map is used with a scale of the extraction pressure control output signal in the extraction map being corrected to be multiplied by “extraction flow rate target value/extraction flow rate actual value” based on a regularly detected extraction flow rate actual value of the steam turbine.

Abstract: A means to effect a trip response regardless of the electro-mechanical actuator type used for improving electro-hydraulic and electro-mechanical integrated control systems for a steam turbine. To achieve this goal, electro-mechanical actuators can be equipped with multiple coils or multiple motors (usually a primary and a secondary). In a dual-coil configuration, the primary is energized according to an output of a PID controller, whereas the secondary coil is regulated by a separate control element. The entire system is powered by means of Uninterruptable Power Supply (UPS) with AC output which can provide sufficient time for trip response using primary coil or motor. At the same time, secondary coil or motor is powered by independent power from a UPS and/or separate battery backup. Whenever trip response is required, and there is a complete main power interruption secondary coil or motor is quickly energized to provide adequate trip response.

Abstract: A method for stopping the operation of a wind turbine is disclosed. The method may generally include receiving signals associated with at least one operating condition of the wind turbine, analyzing the at least one operating condition with a controller of the wind turbine, implementing a first stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a pitch system failure has occurred and implementing a second stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a different wind turbine stop event has occurred.

Abstract: A system, apparatus, and procedure for controlling a fan module. The system comprises a chassis having a backplane, at least one fan module arranged in the chassis, and a profile switch. In one embodiment, the profile switch is arranged in the chassis. Each fan module includes at least one fan and a fan module controller arranged to receive a control signal from a shelf controller. The profile switch is arranged to signal the fan module controller so as to control the at least one fan based on operating profiles corresponding to selected switch positions of the switch.

Abstract: A wind turbine power plant comprises a plurality of wind turbines, each having a rated output and under the control of a power plant controller. The power plant also has a rated output which may be over-rated in response to one or more of electricity pricing data, power plant age and operator demand. The power plant controller can send over-rating demand signals to individual turbines. The controllers at the turbines include a fatigue life usage estimator which estimates a measure of the fatigue life consumed by key components of the turbine. If this measure exceeds a target value for any component, over-rating is prevented at that turbine.

Abstract: A machine includes a rotor supported to rotate about a rotational axis and an actuator arranged to act on the rotor and control a position of the rotor about the rotational axis. A bladed turbomachine wheel is coupled to the rotor and has blade tips that pass closely to an adjacent, non-rotating surface. A sensor is adjacent to the turbomachine wheel and arranged to sense the blade tips and output a position signal representative of the position of blade tips relative to the sensor. A controller is coupled to the sensor and the actuator and is adapted to receive the position signal from the sensor and generate and send a control signal to the actuator to control the position of the rotor based on the position signal from the sensor.

Abstract: A controller receives a power-level command representative of a level of power to be transmitted by a single-spool turboshaft engine to a controllable load. A torque command determined responsive to a measure of inlet pressure, from a control schedule responsive to the power-level command, is representative of a level of torque to be transmitted by an element to drive the controllable load. Under some operating conditions, a rotational speed command provides for at least nearly minimizing a measure of associated fuel consumption when the transmitted torque is regulated to the level corresponding to the torque command by controlling one of the controllable load and a fuel flow to the engine, and the other of the controllable load and the fuel flow to the engine is controlled so as to regulate an associated rotational speed to a level corresponding to the rotational speed command.

Abstract: A machine includes a rotor supported to rotate about a rotational axis and an actuator arranged to act on the rotor and control a position of the rotor about the rotational axis. A bladed turbomachine wheel is coupled to the rotor and has blade tips that pass closely to an adjacent, non-rotating surface. A sensor is adjacent to the turbomachine wheel and arranged to sense the blade tips and output a position signal representative of the position of blade tips relative to the sensor. A controller is coupled to the sensor and the actuator and is adapted to receive the position signal from the sensor and generate and send a control signal to the actuator to control the position of the rotor based on the position signal from the sensor.

Abstract: A method for operating an off-shore wind turbine and a wind-turbine is provided. The off-shore wind turbine is at least temporarily situated in water and includes a rotor with at least one rotor blade and a pitch drive system coupled to the at least one rotor blade. The pitch drive system is adapted for pitching the at least one rotor blade, wherein the wind turbine further includes a wind turbine control. The method includes determining at least one of a water condition; in dependence of the outcome of the determining, defining peak shaver settings; and pitching the at least one rotor blade according to the peak shaver settings. Furthermore, the wind turbine has a sensor adapted for measuring one of the water current-speed, the water current direction and the water level at or close to the wind turbine.

Abstract: A hydropower generating turbine having an impeller housing disposed to receive water, at least one impeller disposed within the impeller housing, at least one adjustable duct pivotally connected to the impeller housing, and, where the duct has a plurality of duct leafs, wherein the duct leafs articulate and cause the duct to converge and diverge for selectively disposing a fluid about the impeller. The ducts may be inflow or outflow ducts, and the turbine may react to a change in the fluid and alter the shape of the impeller. Further, the turbine may have an automated controller where variable change in the flow is detected by a sensor and transmitted to the automated controller to cause a directional shift in the multidirectional turbine.

Abstract: A method, system and computer program product for operating a wind turbine is disclosed. For operating the wind turbine a set of operational data points are sensed via a sensing module. The set of operational data points may include bending stress values. Based on the bending stress values, a load scenario indicator value may be computed. Further, based on the set of operational data points a loading threshold value may be obtained. At least one operating parameter of the wind turbine is changed if the load scenario indicator value exceeds the loading threshold.

Abstract: A turbomachine system includes a compressor having a compressor intake and a compressor extraction outlet, and an inlet system fluidly connected to the compressor intake and the compressor extraction outlet. The inlet system includes a plenum having a first end portion that extends to a second end portion through an intermediate portion. The inlet system also includes a heating system having a plurality of conduits extending horizontally through the intermediate portion of the plenum and arranged in a vertical relationship. Heated air from the compressor extraction outlet passes through the plurality of conduits and raises a temperature of ambient air passing through the plenum and into the compressor intake.

Abstract: Method and apparatus for vibration-based automatic condition monitoring of a wind turbine, comprising the steps of: determining a set of vibration measurement values of the wind turbine; calculating a frequency spectrum of the set of vibration measurement values; calculating a cepstrum of the frequency spectrum; selecting at least one quefrency in the cepstrum, and detecting an alarm condition based upon an amplitude of the cepstrum at the selected quefrency, and a wind turbine therefor.

Abstract: It is presented a method for controlling the instantaneous power output from a wind power plant. Wind speed and wind directions are determined, wherein an upper limit power output for the specific wind speed and wind direction is determined from a previously measured power output value at the same wind speed and wind direction, and wherein the power output of the wind power plant is controlled based on the determined upper limit power output. A wind power plant is also presented.

Abstract: A method of validating a wind turbine including a rotor includes intentionally inducing a loading imbalance to the rotor. The method also includes measuring the loading imbalance induced to the rotor, transmitting a signal representative of the measured loading imbalance to a calibration module, and at least one of detecting an error and calibrating at least one component of the wind turbine based on the signal.

Abstract: A variable geometry turbine of the kind used in a turbocharger has a variable geometry element such as a nozzle ring or an annular array of swing vanes that is operated by an actuator. The actuator has an output shaft coupled to a transmission mechanism for moving the variable geometry element. A rotary sensor device coupled to the output shaft of the actuator has a sensor wheel with a stop, slip clutch mechanism and a rotary position sensor. The device converts movement of the actuator output shaft into rotation of the wheel and the sensor generates an output signal representative of the rotary position of the wheel to provide a value indicative of the position of the variable geometry element.

Abstract: Method and apparatus for vibration-based automatic condition monitoring of a wind turbine, comprising the steps of: determining a set of vibration measurement values of the wind turbine; calculating a frequency spectrum of the set of vibration measurement values; calculating a cepstrum of the frequency spectrum; selecting at least one quefrency in the cepstrum, and detecting an alarm condition based upon an amplitude of the cepstrum at the selected quefrency, and a wind turbine therefor.

Abstract: A fan system includes a fan and a fan rotation speed control. The speed control is operable to command the fan to rotate at a speed selected from a certain range of rotation speeds. A fan oscillation detector may be coupled with the fan to detect oscillation of the fan as the speed control is operated to rotate the fan at various speeds among the range of fan rotation speeds. The fan oscillation detector may comprise an accelerometer or other device. Oscillation amounts detected by the oscillation detector are compared against each other or against an oscillation threshold value. A programmer device identifies fan rotation speeds at which the oscillation amount exceeds the threshold or is otherwise unacceptable, and programs the fan rotation speed control to prevent an operator from being able to select those speeds at which the oscillation amount exceeds the threshold or is otherwise unacceptable.

Abstract: In fluid flow measurement applications, apparatus and associated systems, computer program products, and methods may include a positive displacement fluid flow meter having an actuator to control fluid flow through the meter, and further having two or more rotating members with substantially parallel axes that rotate in response to the actuator and to fluid flow through the meter. In various implementations, the actuator may promote and/or retard a fluid flow being measured through the meter. In some examples, the fluid flow meter may operate as a pump to controllably increase a line pressure, controllably regulate a fluid flow rate by opposing rotation of the rotating members, substantially stop a fluid flow, and/or reverse a base fluid flow direction. In an illustrative example, the meter may operate to accurately monitor and control fluid flow (e.g., fluid pressure, velocity, and/or volume) before, during, and/or after a line break.

Abstract: A fan control apparatus and method that sets a stop period constant at a starting time by adding a fan control in a time axis to a fan control by a temperature sensor. The fan control apparatus includes a temperature sensor that detects the temperature in the equipment body; and a CPU and a sub-microcomputer that has a temperature control function, that perform the control of the cooling fans according to the detected temperature value. The CPU performs a communication with a server connected to the equipment body via a network; and the sub-microcomputer performs the control of the cooling fans according to the time value based on the communication commencement.

Abstract: A dynamically reconfigurable wind turbine blade assembly includes a plurality of reconfigurable blades mounted on a hub, an actuator fixed to each of the blades and adapted to effect the reconfiguration thereof, and an actuator power regulator for regulating electrical power supplied to the actuators. A control computer accepts signals indicative of current wind conditions and blade configuration, and sends commands to the actuator power regulator. Sensors measure current wind conditions and current configurations and speed of the blades. An electrical generator supplies electrical power to the assembly. Data from the sensors is fed to the control computer which commands the actuator power regulator to energize the actuators to reconfigure the blades for optimum performance under current wind conditions.

Abstract: An upper reservoir-side conduit or a lower reservoir-side conduit is branched in the vicinity of pump-turbine ends and at least a first pump-turbine out of a plurality of pump-turbines which share the conduit portions located farther than the branch points with the other pump-turbine or pump-turbines is provided with a rotational speed increase detector. When it is detected that the rotational speed of the first pump-turbine has exceeded a second predetermined value higher than a rated speed, a command is issued also to at least one of the other pump-turbines to limit the guide vane closing speed in that pump-turbine to a speed approximately equal to or lower than the speed after the shift to a slow closing of the guide vanes.

Abstract: The angular extent of the flow path in a fan scroll is extended by reducing the rate of radial expansion of the flow path. By extending the angular as circumferential extent of the scroll flow path downstream of the fan impeller ANC structure can be located in/on the scroll while being located a sufficient distance downstream of the impeller. The flow path length can be increased without increasing the cubage of the scroll and, if desired, a further flow path increase can be achieved by a combination of the reduced rate of radial expansion together with increasing the cubage.

Abstract: A method and apparatus for determining turbine rotor stresses in real time enables increased operation efficiency and more accurate stress determinations. The system calculates rotor bore and surface temperatures based on the time response of the rotor. The rotor surface temperature is measured using a sensor such as a thermocouple, and the measured rotor surface temperature is used to calculate rotor bore temperature and rotor average temperature based on time constants determined as a function of rotor geometry and material. The rotor surface thermal stress and the rotor bore thermal stress can be determined based on the measured and calculated temperatures.

Abstract: An upper reservoir-side conduit or a lower reservoir-side conduit is branched in the vicinity of pump-turbine ends and at least a first pump-turbine out of a plurality of pump-turbines which share the conduit portions located farther than the branch points with the other pump-turbine or pump-turbines is provided with a rotational speed increase detector. When it is detected that the rotational speed of the first pump-turbine has exceeded a second predetermined value higher than a rated speed, a command is issued also to at least one of the other pump-turbines to limit the guide vane closing speed in that pump-turbine to a speed approximately equal to or lower than the speed after the shift to a slow closing of the guide vanes.

Abstract: A turbomachine having variable angle diffuser vanes is demonstrated with the use of a centrifugal pump. The performance of a diffuser is enhanced greatly by the use of adjustable angle diffuser vanes which can be set to a wide range of vane angles to provide a variable size of an opening between adjacent vanes. The demonstrated pumping system has a significantly wider operating range than that in conventional pumping systems over a wide flow rate, and is particularly effective in the low flow range in which known diffuser vane arrangements would lead to surge in the entire system and other serious operational problems. A number of examples and formulae are given to demonstrate the computational methods used to select a vane angle for a given set of operating conditions of the turbomachine.

Abstract: A turbomachinery is presented to provide stable operation at fluid flow rates much lower than the design flow rate without introducing surge in the device. This is achieved by providing a diffuser with variable angle vanes. The vane angle at low flow rates is adjusted so as to minimize the diffuser loss of the exiting fluid stream from the impeller. Since the flow angle of the exit flow of the impeller is a function only of the non-dimensional flow rates, and does not depend on the flow angle at the inlet the impeller, therefore, the vane angles can be regulated to achieve a stable operation of the impeller without producing surge of the turbomachinery at flow rates lower than the design flow rate. To optimize the performance of the turbomachinery, in addition to the variable angle vanes, an inlet guide vane having variable vane angle is provided so that the turbomachinery can be operated at the required flow rate and head pressure.

Abstract: A turbomachinery is presented to provide stable operation at fluid flow rates much lower than the design flow rate without introducing surge in the device. This is achieved by providing a diffuser with variable angle vanes. The vane angle at low flow rates is adjusted so as to minimize the diffuser loss of the exiting fluid stream from the impeller. Since the flow angle of the exit flow of the impeller is a function only of the non-dimensional flow rates, and does not depend on the flow angle at the inlet the impeller, therefore, the vane angles can be regulated to achieve a stable operation of the impeller without producing surge of the turbomachinery at flow rates lower than the design flow rate. To optimize the performance of the turbomachinery, in addition to the variable angle vanes, an inlet guide vane having variable vane angle is provided so that the turbomachinery can be operated at the required flow rate and head pressure.

Abstract: A method and apparatus are disclosed for controlling the rotational speed of gas and steam turbines, and hot gas expanders, with each of these drivers driving a rotational load by way of a shaft. To accomplish this control technique, it is necessary to easily and accurately calculate the amount of power which must be shed by the driver(s) to maintain a constant speed, i.e., neither accelerating nor decelerating. Action must be taken to reduce the power applied to the shaft by this amount. The method incorporates an open-loop approach and uses a time derivative to moderate the open-loop action accordingly.

Abstract: According to the invention there now is provided a method of producing a sintered titanium based carbonitride alloy with 325 weight-% binder phase with extremely good properties at extremely fine machining with high cutting speeds and low feeds. The method relates to the use of a raw material comprising a complex cubic carbonitride containing the main part of the metals from groups IV and V of the periodic system and carbon and nitrogen to be found in the finished alloy whereby said alloy has the composition0.87.ltoreq.X.sub.IV .ltoreq.0.990.66.ltoreq.X.sub.C .ltoreq.0.76where X.sub.IV is the molar ratio of the group IV elements of the alloy and X.sub.C is the molar ratio of carbon.

Abstract: A method of operating a multistage turbocompressor or of monitoring the pump limit thereof, whereby the pump limit function is stored in the control unit in the form Y=m.F+b and the coefficients m and b are determined by the linear relationshipsm=m.sub.0 +m.sub.1.dT.sub.s +.SIGMA.m.sub.2i.dT.sub.rib=b.sub.0 +b.sub.1.dT.sub.s +.SIGMA.b.sub.2i.dT.sub.riwhere T.sub.s and T.sub.ri represent the intake temperature and the backcooling temperatures following coolers after each turbocompressor and dT.sub.s and T.sub.ri and reference temperatures T.sub.ref. The system automatically compensates for the shift of the pump limit with temperature and allows operation closer to the pump limit or boundary for stable aerodynamic operation.

Abstract: When controlling a turbocompressor to prevent pumping there is generated a control signal which controls a blowoff or recycle valve attached to the compressor outlet by continuously monitoring the working point or operating condition coordinates and comparing the coordinates with a blowoff line defined by operating conditions producing a pumping. Upon the occurrence of a pumping surge, a signal is generated which can control for instance the quick opening of the blowoff valve. In addition, according to the invention the signal generated upon the occurrence of a pumping surge is also utilized to initiate a new fixation of the blowoff line or the pumping limit line.

Abstract: An apparatus for controlling a hydraulic turbine is disclosed comprising a hydraulic circuit to control the positioning of turbine runner blades and a hydraulic circuit to control the positioning of turbine wicket gates. The runner blade hydraulic circuit comprises a solenoid valve for normal operation of the blades and a slow rate servovalve for moving the blades when the actual blade position differs from a desired position by less than a predetermined tolerance. The wicket gate circuit comprises a solenoid valve for normal control of the gates. A diverter directs flow from the solenoid valve to a flow rate control valve when the difference between the actual and desired position of the gates is less than a second predetermined tolerance.

Abstract: A microprocessor-based controller for an extraction type steam turbine-generator unit capable of selecting from a variety of predetermined control strategies and implementing corresponding valve position control loops by generating appropriate valve position control signals in accordance with operator-chosen setpoint signals and turbine operating level signals. In a particular control strategy, automatic system frequency correction is achieved in a load control mode upon separation of the turbine-generator from the utility power grid, by detecting turbine speed deviation beyond predetermined limits and correcting turbine speed to synchronous speed without the need for operator intervention.

Abstract: A system for regulating the liquid level (20) in a vapor generator (10), in which the incoming flow of feed liquid (54) is regulated (48) in response to the difference between the measured liquid level (76) and a reference level (80), the difference between the exiting vapor mass flow rate (64) and the incoming liquid mass flow rate (56), and a function of the measured incoming liquid temperature (92). The temperature function produces a gain value (98), which increases in response to decreasing incoming liquid temperature.

Abstract: In a power control for a turbo-generator, the acceleration power of the difference between the mechanical power supplied to the turbo-generator set and the power delivered by it is determined and, if the supplied power preponderates, a correction signal directed toward closing control valves is fed to the power control by means of a valve positioning controller, Thereby, the power control need not be disconnected in the event of disturbances such as load shedding and network short circuit, but can practically remain engaged continuously.

Abstract: A variable limit is utilized to prevent a position controller which requires a velocity set point signal from overdriving a stuck control valve. Control based on a comparison of the actual position to desired position is utilized unless the valve is stuck. If the valve is stuck, the variable limit controls the velocity set point provided to the position controller until such time as the valve becomes unstuck.

Abstract: In a process in which both a turbine or motor and an expander are utilized to drive a compressor, the use of the expander is substantially maximized while still insuring that the driving force applied to the turbine or motor does not go below a low limit. A variable limit is also utilized to prevent a stuck valve from being overdriven by a controller.

Abstract: A multiple-purpose, closed-loop, automatic control system is disclosed, having a system controlled, and means for detecting a controlled variable output from the system controlled and for converting the controlled variable into an electrical feedback signal. The system further includes signal converting means for receiving the feedback signal and for converting the signal into an angular displacement corresponding to the feedback signal; means for comparing the controlled variable with a preset desired value and for selectively opening or closing a forward or reverse controlling circuit; and controlling means for automatic control over the system controlled to keep the controlled variable within the preset desired value. The controlling means includes the forward and the reverse controlling circuits selectively opened or closed by the comparing means, a braking control circuit and a driving mechanism responsive to the forward and reverse control circuits and the braking control circuit.

Abstract: A process and apparatus for operating a turbocompressor having an output at an actual value of flow and pressure and a blow-off valve for regulating the output to prevent surging of the output above a surge limit and to prevent a reduction of the output below a minimum value, with a comparing unit for measuring the actual value, and a controller unit for controlling the blow-off valve in accordance with the output of the comparing unit comprising, forming a first difference value between the theoretical value and the actual value, forming a delayed value from the difference value and thereafter forming a second difference value between the delayed value and the first difference value to control the blow-off valve.

Abstract: A steam turbine control system comprising a primary and an auxiliary manual turbine controller, each said turbine controller including a set of valve position setpoint controllers for close-loop control of the turbine steam admission valves, is disclosed. Each valve position setpoint controller operates, at times, on a position error signal to generate a valve position control signal which controls the rate of valve position movement of a corresponding turbine steam admission valve. The steam admission valves are closed-loop controlled by a selected set of said primary and auxiliary valve position setpoint controllers. The set of valve position control signals corresponding to the selected set of position setpoint controllers are coupled to their respective turbine steam admission valves for controlling the rate of position movement therein. The valve position error and position control signals of the unselected set of said controllers are maintained at approximately zero potential.

Abstract: A steam turbine is provided with an automatic digital computer controller and a backup analog controller which are interfaced with an electrohydraulic position control for the turbine throttles and governor valves. Valve position signals are generated by transducers and applied to the valve position control along with position setpoint signals from the computer or the backup controller for the purpose of generating valve control signals which drive the valves until the position setpoints are satisfied. The position signals are also applied to the computer where they are compared to the computer valve position setpoints. The automatic controller and the analog backup controller each have a speed/load control which generates the valve position setpoints in accordance with a speed or load reference, and the backup control tracks the computer setpoints during automatic control.

Abstract: 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 speed control loop which is implemented with computer operations.

Abstract: A turbine control system for changing over a throttle governing operation of a steam turbine to a nozzle governing operation thereof and vice versa by controlling control valves on the basis of a main control flow-rate request signal comprises function generators grouped according to the two governing operations and operating to produce function outputs in response to the opening degrees of the control valves. The function outputs are biased according to the two governing operaton and applied to respective high-value gates, the output signals of which are compared with the main control flow-rate request signal to control the opening degrees of the control valves in such a manner that the flow rate of steam introduced through the control valves into the steam turbine are maintained constant during the speed governing operation changing period.

Abstract: 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.

Abstract: In a system and method for automatically starting, synchronizing and operating a steam turbine, proportional plus integral feedbck control utilizing digital computer systems is adapted to correspond to physical valve operation by applying integration limits. Useful for both speed and load control modes of operation, the demand signal is compared with prior values thereof, and the differential is both multiplied by a proportional gain factor, and integrated in the computer utilizing numerical integration techniques. The integrated total is kept within a desired range by applying upper and lower limits, and the limited integral is combined with the proportional factor, further limited, as desired, and appropriately scaled for use as a process variable.

Abstract: 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.

Abstract: 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.