초록 ▼

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 operat

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. The extraction mode of turbine operation is subdivided into a provided set of mutually exclusive extraction control loops, each of which can be placed in service in a bumpless fashion upon transition from any other extraction control loop in a predetermined sequence. Upon a return from the manual mode of turbine operation to the automatic mode, a particular extraction control loop is automatically placed in service without the need for operator intervention.

대표청구항 ▼

1. A control apparatus for operating an extraction steam turbine-electric power generation system so as to allow a bumpless transfer into an extraction mode of operation for locally controlling extraction steam pressure in a predetermined local extraction pressure control loop, or for allowing a bum

1. A control apparatus for operating an extraction steam turbine-electric power generation system so as to allow a bumpless transfer into an extraction mode of operation for locally controlling extraction steam pressure in a predetermined local extraction pressure control loop, or for allowing a bumpless transfer from said predetermined local extraction pressure control loop into any one of three other extraction modes of operation, one for remotely controlling extraction steam pressure in a predetermined remote extraction pressure control loop, one for locally controlling extraction steam flow in a predetermined local extraction flow control loop, or one for remotely controlling extraction steam flow in a predetermined remote extraction flow control loop, said apparatus comprising: a turbine extraction valve; a valve controller means for positioning said extraction valve; a pressure transmitter means for providing a pressure feedback signal corresponding to the existing level of said extraction steam pressure in said system; a flow transmitter means for providing a flow feedback signal corresponding to the existing level of said extraction steam flow in said system; an extraction control loop selection controller means for determining one of four transitional operating states, a first transitional operating state corresponding to entry into said predetermined local extraction pressure control loop, a second transitional operating state corresponding to entry into said predetermined remote extraction pressure control loop, a third transitional operating state corresponding to entry into said predetermined local extraction flow control loop, or a fourth transitional operating state corresponding to entry into said predetermined remote extraction flow control loop; an operator panel means for determining the operation of said extraction control loop selection controller means in accordance with an operator selection at said operator panel means; an extraction transition reference controller means for determining an extraction transition reference signal equal to said pressure feedback signal in said first or second transitional operating states or equal to said flow feedback signal in said third or fourth transitional operating states; an extraction valve pressure transition setpoint controller means operative with said extraction transition reference controller means for determining an extraction valve pressure setpoint signal in said first or second transitional operating states in accordance with a predetermined function of said extraction transition reference signal, said pressure feedback signal and an existing extraction valve setpoint signal; an extraction valve flow transition setpoint controller means operative with said extraction transition reference controller means for determining an extraction valve flow setpoint signal in said third or fourth transitional operating states in accordance with a predetermined function of said extraction transition reference signal, said flow feedback signal and said existing extraction valve setpoint signal; and an extraction valve setpoint selection controller means operative with said extraction valve pressure transition setpoint controller means and said extraction valve flow transition setpoint controller means for selecting said extraction valve pressure setpoint signal in said first or second transitional operating states or said extraction valve flow setpoint signal in said third or fourth transitional operating states and establishing said existing extraction valve setpoint signal operative with said valve controller means at the value of said selected setpoint signal. 2. The control apparatus of claim 1, wherein operation of said control apparatus in said first transitional operating state precedes operation in said second, said third or said fourth transitional operating states, and in which said control apparatus is generated through said first transitional operating state during a transition from any of said second, said third, or said fourth transitional operating states to any other of said second, said third, or said fourth transitional operating states. 3. A control apparatus for operating an extraction steam turbine-electric power generation system so as to allow a bumpless transfer into an extraction mode of operation in which adjustments to an extraction valve are made for locally controlling extraction steam pressure in a predetermined local extraction pressure control loop, or for allowing a bumpless transfer from said predetermined local extraction pressure control loop into any one of three other extraction modes of operation, one for remotely controlling extraction steam pressure through adjustments to said extraction valve in a predetermined remote extraction pressure control loop, one for locally controlling extraction steam flow through adjustments to said extraction valve in a predetermined local extraction flow control loop, or one for remotely controlling extraction steam flow through adjustments to said extraction valve in a predetermined remote extraction flow control loop, said apparatus comprising: an extraction control loop selection controller means for determining one of four transitional operating states, a first transitional operating state corresponding to entry into said predetermined local extraction pressure control loop, a second transitional operating state corresponding to entry into said predetermined remote extraction pressure control loop, a third transitional operating state corresponding to entry into said predetermined local extraction flow control loop, or a fourth transitional operating state corresponding to entry into said predetermined remote extraction flow control loop; an operator panel means for determining the operation of said extraction control loop selection controller means in accordance with an operator at said operator panel means; an extraction transition reference controller means for determining an extraction transition reference signal equal to the existing level of said extraction steam pressure in said system in said first or second transitional operating states or equal to the existing level of said extraction steam flow in said system in said third or fourth transitional operating states; an extraction valve pressure transition setpoint controller means operative with said extraction transition reference controller means for determining an extraction valve pressure setpoint signal in said first or second transitional operating states in accordance with a predetermined function of said extraction transition reference signal, said existing extraction steam pressure level and an existing extraction valve setpoint signal; an extraction valve flow transition setpoint controller means operative with said extraction transition reference controller means for determining an extraction valve flow setpoint signal in said third or fourth transitional operating states in accordance with a predetermined function of said extraction transition reference signal, said existing extraction steam flow level and said existing extraction valve setpoint signal; and an extraction valve setpoint selection controller means operative with said extraction valve pressure transition setpoint controller means and said extraction valve flow transition setpoint controller means for selecting said extraction valve pressure setpoint signal in said first or second transitional operating states or said extraction valve flow setpoint signal in said third or fourth transitional operating states and establishing said existing extraction valve setpoint signal operative with said extraction valve at the value of said selected setpoint signal. 4. The control apparatus of claim 3, wherein operation of said control apparatus in said first transitional operating state precedes operation in said second, said third or said fourth transitional operating states, and in which said control apparatus is operated through said first transitional operating state during a transition from any of said second, said third, or said fourth transitional operating states to any other of said second, said third, or said fourth transitional operating states. 5. The control apparatus of claim 3, further comprising: a reinsertion logic controller means for determining, in the presence of a set of predetermined system operating conditions, said first transitional operating state, said reinsertion logic controller means operative with said operator panel means and said extraction control loop selection controller means. 6. The control apparatus of claim 5, wherein said set of predetermined system operating conditions corresponds to an operation in which said control apparatus has been restored to operation after being inoperative concurrent with both generation of a megawatt output from said extraction steam turbine-electric power generation system and a position of said extraction valve corresponding to said extraction mode of operation. 7. The control apparatus of claim 3, further comprising a remote control means which tracks the existing level of said extraction steam pressure and said extraction steam flow in said system and generates an equivalent remote control pressure reference signal and an equivalent remote control flow reference signal, respectively, said remote control pressure reference signal and said remote control flow reference signal connected to said extraction transition reference controller means. 8. The control apparatus of claim 3 wherein said first transitional operating state is inoperable unless the existing megawatt output level from said system is above approximately 20% of the rated load of said system. 9. The control apparatus of claim 3, wherein a digital computer means and an input and output interface means having analog and digital conversion capability suitable for use in process environments are employed to provide said extraction control loop selection controller means, said extraction transition reference controller means, said extraction valve pressure transition setpoint controller means, said extraction valve flow transition setpoint controller means, said extraction valve setpoint selection controller means. 10. The control apparatus of claim 9, wherein said digital computer means is programmed to provide a set of modular functional control blocks which are employed to form said extraction control loop selection controller means, said extraction transition reference controller means, said extraction valve pressure transition setpoint controller means, said extraction valve flow transition setpoint controller means, and said extraction valve setpoint selection controller means. 11. The control apparatus of claim 10, wherein the names of said modular functional control blocks are entered into said digital computer means in an interactive fashion. 12. The control apparatus of claim 11, wherein a translator means handles said functional control blocks in accordance with the sequence of entry into said digital computer means to form a software application program, each line of said software application program corresponding to one modular functional control block. 13. The control apparatus of claim 12, wherein an interpreter means is employed to execute said software application program in said digital computer means on a line-by-line basis in accordance with the lines of the software application program. 14. A method of operating an extraction steam turbine-electric power generation system so as to allow a bumpless transfer into an extraction mode of operation for locally controlling extraction steam pressure through adjustments to an extraction valve in a predetermined local extraction pressure control loop, or for allowing a bumpless transfer into any one of three other extraction modes of operation, one for remotely controlling extraction steam pressure through adjustments to said extraction steam valve in a predetermined remote extraction pressure control loop, one for locally controlling extraction steam flow through adjustments to said extraction valve in a predetermined local extraction flow control loop, or one for remotely controlling extraction steam flow through adjustments to said extraction valve in a predetermined remote extraction flow control loop, said method comprising the steps of: determining one of four transitional operating states, a first transitional operating state corresponding to entry into said local extraction pressure control loop, a second transitional operating state corresponding to entry into said predetermined remote extraction pressure control loop, a third transitional operating state corresponding to entry into said predetermined local extraction flow control loop, and a fourth transitional operating state corresponding to entry into said predetermined remote extraction flow control loop; selecting said first transitional operating state prior to selection of said second, said third, or said fourth transitional operating state or selecting said first transitional operating state prior to selection of said second, said third, or said fourth transitional operating state when either of said second, said third, or said fourth transitional operating state was last selected; determining, if in said first or said second transitional operating states, an extraction transition reference signal equal to the existing level of said pressure in said system, an extraction valve pressure setpoint signal in accordance with a predetermined function of said extraction transition reference signal, the existing level of said pressure in said system, and the existing adjustment of said extraction valve, and operating said extraction valve in accordance with said extraction valve pressure setpoint signal; and determining, if in said third or said fourth transitional operating states, an extraction transition reference signal equal to the existing level of said flow in said system, an extraction valve flow setpoint signal in accordance with a predetermined function of said extraction transition reference signal and the existing level of said flow in said system, and the existing adjustment of said extraction valve, and operating said extraction valve in accordance with said extraction valve flow setpoint signal.