Abstract: A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. The control system includes a digital automatic control and an analog backup control which are interfaced to control the gas turbine fuel flow for speed and load control purposes. The backup control includes a speed/load control which functions on a feedforward speed control basis without speed feedback correction and on a feedforward load control basis without load feedback correction. The forward speed/load control channel is subjected to high and low limit action and the fuel reference output is applied to a feedback type fuel control, i.e. a throttle valve positioning control. Limit action is also placed on the forward speed/load control channel by a temperature control, a surge control and an overspeed control.

Abstract: A steam turbine operates with a control system having a programmed digital computer for automatically controlling steam flow to satisfy turbine speed or load demand during turbine startup, synchronization and load operation. Steam flow is controlled throughout the entire startup sequence by means of speed control signals determined by the computer as a function of monitored turbine operating conditions. While under load operation the turbine is under digital computer load control, and operational parameters are monitored by the digital computer.

Abstract: A lifting frame is provided for use in lifting elongated room-size prefabricated building modules and other large, heavy and bulky elongated loads having asymmetrical or lopsided weight distributions in the direction of elongation. The lifting frame includes a pair of generally parallel, side-by-side, spaced apart elongated beams and a pair of cross-brace beams running at right angles to the elongated beams and located therebetween. The elongated beams are adapted to be releasably fastened to the upper portion of the building module or other load with the longer dimension of such beams running in the same general direction as the longer dimension of the building module or other load. The cross-brace beams are adapted to receive and laterally position the lower ends of the cables of a cable-type lifting sling.

Abstract: A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. An automatic digital portion of the control system functions with temperature and other detectors to provide temperature limit control for the gas turbines through the fuel valve position controls provided therefor. A blade path temperature reference is generated as a function of combustor shell pressure during the startup and load modes of operation, and during the load mode of operation the blade path temperature reference is further generated with dependence on the actual turbine exhaust temperature. In particular, the turbine blade path temperature is allowed to rise under loading operation until it reaches a limit value defined by a predetermined combustor shell pressure characteristic curve.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. A condenser receives the spent steam from the steam turbine for converting it into condensate. The steam generator includes a deaerator for receiving the condensate flow from the condenser and for storing it in a storage portion, a feedwater pump for directing the stored condensate through a first heat exchange tube whereby heat is transferred from the gas turbine exhaust gases to the fluid, a main drum for receiving and storing the heated fluid and a second heat exchange tube for heating the fluid by the gas turbine exhaust gases into superheated steam to be supplied to the steam turbine.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. A condenser is associated with the steam turbine for converting the spent steam from the steam turbine into condensate to be supplied to the steam generator. The steam generator includes a low pressure storage tank, a first heat exchange tube, a boiler feedwater pump for directing fluid from the low pressure storage tank through the first heat exchange tube, a main storage drum, a second heat exchange tube, and a high pressure recirculation pump for directing water from the main storage drum through the second heat exchange tube. An afterburner further heats the exhaust gas turbine gases passed to the first and second heat exchange tubes.

Abstract: A combined cycle power plant includes gas and steam turbines, gas turbine afterburners, steam generators, and a digital/analog control system. A megawatt load control system varies a fuel control signal to govern a detected power output according to a reference value, the fuel control signal determining the flow rate of fuel to a gas turbine. An afterburner is connected to heat the exhaust gas from the gas turbine. Both the gas turbine and the afterburner are adapted to use gas and liquid fuels. During gas turbine fuel transfer, the gas and liquid fuel flows are controlled in response to the fuel control signal to compensate power output disturbances that typically result from various nonlinearities of fuel system elements. Afterburner fuel transfer is initiated upon completion of gas turbine transfer.

Abstract: 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.

Abstract: A gas turbine power plant is provided with an industrial gas turbine which drives a generator coupled to a power system through a breaker. The turbine-generator plant is operated by a hybrid control system having digital function capability during sequenced startup, synchronizing, load buildup and steady state load, and shutdown operations. The control system also contains monitoring and protective subsystems which function through all stages of operation, with redundancy and permissive features which maximize turbine availability.

Abstract: A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. The control system includes an automatic control and a backup control which are interfaced to operate the gas turbine throttle valve for speed and load control purposes and to provide for manual/auto transfers. The backup control includes a startup control which functions on the basis of a feedforward fuel schedule ramp function. Between ignition speed and 78% synchronous speed, the ramp function is a linear function of fuel demand versus speed with a predetermined slope. From 78% of synchronous speed to idle speed, the ramp function is a linear function with a lesser slope.

Abstract: A gas turbine power plant is provided with an industrial gas turbine which drives a generator coupled to a power system through a breaker. The turbine-generator plant is operated by a hybrid control system having digital function capability during sequenced startup, synchronizing, load buildup and steady state load, and shutdown operations. The control system also contains monitoring and protective subsystems which function through all stages of operation, with redundancy and permissive features which maximize turbine availability.

Abstract: In a turbine system with first and second turbine stages, each having a bypass line thereacross, provision is made for utilizing only the valving of the first turbine stages to control the acceleration of the shaft driven by the turbine system from start-up to synchronous speed. At the same time, provision is made for diverting enough of the flow to the second turbine stages to meet the requirements of those stages.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including a turbine control, a boiler control and a plant unit master; each of the aforementioned controls includes integrating or adaptive controllers responsive to error signals to effect a desired control and ramp generators to provide an output against which a control process may be tracked. The integrating controllers include an integrating circuit for integrating an input error signal and a proportional circuit responsive to the error signal for providing an output signal to be summed with the output of the integrating circuit. The constant of the proportional circuit and the time constant of the integrating circuit are changed as a function of an index. In a control for an electric power plant, the index is the load reference provided by the plant unit master. A ramp generator is suggested that is capable of generating linear ramps at a fixed rate toward a known value, e.g.

Abstract: A digital computer control system is provided for operating a steam turbine in an electric power plant. The computer develops steam valve position signals to control turbine speed and load. Various turbine temperature, pressure and other process parameter signals are coupled to the computer which stores the parameter values along with other parameters such as control loop setpoints in its memory. Another computer at the plant level or at the system dispatch level is coupled to the turbine computer through a data link which includes data link programs in each computer and data transmitter and receiver circuitry connected to the two computers. The higher level computer is the controlling computer on the data link. Control words are used to identify data transmission modes and validity checks are made on transmitted words. Turbine computer core data is accessible and transmittable to either higher level computer.

Abstract: The stages of a turbine system are independently controlled to produce a desired system power output by monitoring and comparing the power characteristics of each stage to the desired power output. Flow through each of the stages is adjusted until the desired power output is generated, while any flow that is passing through bypass lines about each of the turbine stages is varied inversely to the variations in the flow through the turbine stages. Non-linearities occurring in the system are offset by appropriate modification of the control of each stage and by comparison of the power output of the system with the power requirements to direct continuing control until the power requirements are met.

Abstract: The throttle and governor valves of a steam turbine are operated by a digital computer control system to provide speed and load control for the turbine. The computer includes a speed and load control which periodically generates control outputs and a separate logic control which responds to panel and contact inputs to generate logicals which structure the speed and load control. An analog scan periodically enters feedback parameters into the computer for use by the controls. An input contacts scan enters feedback logicals into the computer on demand, or under certain conditions periodically. A monitor operates with an auxiliary synchronizer to control the execution of the scans and the controls. The speed and load controls are bid for execution once each second to generate the control outputs which are applied to an external electrohydraulic control for the valves.

Abstract: A digital computer system is employed to produce power system control. The computer system employs an economic dispatch program, a unit selection program and a tie line interchange program to determine off line a tie line schedule and unit commitments needed to satisfy economically and safely a load forecast over a selected time interval such as 24 hours. In on line closed control loop operation, the computer system employs a load and frequency control program which uses the tie line schedule and other quantities in determining area control error. The control program develops a system error representation which reflects a smoothed present and anticipated area control error. The system error representation is distributed into individual generator plant control signals under economic dispatch program and unit selection program control and under constraint of programmed plant limits to assure that each generation move is error correcting as well as optimally economic.