US3848138A
Expired / Lapsed
US
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Method of effecting fast turbine valving for improvement of power system stability
Assignee: FAST LOAD CONTROL Inc
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Filing: 1973-08-15
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Granted: 1974-11-12
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Expires: 1993-08-15
Abstract
Abstract As an improved way of effecting fast valving of turbines of power system steam-electric generating units for the purpose of improving the stability of power transmission over transmission circuits to which their generators make connection when stability is threatened by line faults and certain other stability endangering events, and in which intercept valves are rapidly closed on a momentary basis, the procedure of intercept valve closure is supplemented by simultaneously initiating turbine and steam supply source control programs which (a) being into effect a sustained reduction in turbine driving power via employment of measures which may include full closing of some or all control valves and/or employment of preprogrammed control valve repositioning, with provision to automatically divert high pressure steam to the condenser or to atmosphere as a way to prevent discharge of steam through high pressure safety valves, (b) bring into effect a rapidly executed process of reduction of rate of generation of steam within steam supply sources, and (c) initiate a control program that effects a predetermined degree of partial reopening of intercept valves early in the course of the generator rotor''s first backward swing, following which intercept valves are further opened and control valve positions optionally revised in preprogrammed ways with the overall effect that in the period following the first forward swing the magnitude of turbine driving power is caused to hold below the value that applied prior to the event that initiated fast valving and to at most only briefly exceed a final sustained value that can be preset.
Inventors
- 👤 R Park
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:13
CPC Classifications
F; F01; F01D; F01D17/00; F01D17/20; F01D17/22; F01D17/24; F01D21/00; F01D21/02; F01K; F01K7/00; F01K7/16; F01K7/22; F01K7/24
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
343 words
In a steam-electric installation which incorporates a reheater, power operated relief valves located ahead of the high pressure turbine, which are so controlled as to open and discharge steam to atmosphere when pressure ahead of the valve or valves exceeds a preset value that is less than that at which the turbine''s high pressure safety valves are set to open, and to reclose when pressure falls below a preset value which exceeds normal operating pressure ahead of the turbine, which installation is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoid development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of, 1. providing within the turbine and steam generator control system, for response to a fast valving initiation signal input by bringing into effect preprogrammed jointly effected processes of, a. intercept valve closure effected fast enough to have a favorable effect on generator rotor first swing stability, and control valve repositioning plus intercept valve reopening so effected as to cause turbine driving power subsequent to generator rotor first forward swing to hold below a preset value that is less than the driving power that applied prior to the event that brought about development of the signal, b. runback of rate of steam production within the steam generator to a value that will cause termination of the discharge of steam through said power operated relief valves that will at first take place, with provision so that said runback is effected rapidly enough to avoid overheating of the reheater, 2. providing in a preprogrammed manner so that a fast valving signal is generated and transmitted aS an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 2
Dependent Claim
343 words
In a steam-electric installation which incorporates a reheater, power operated relief valves located ahead of the high pressure turbine, which are so controlled as to open and discharge steam to atmosphere when pressure ahead of the valve or valves exceeds a preset value that is less than that at which the turbine''s high pressure safety valves are set to open, and to reclose when pressure falls below a preset value which exceeds normal operating pressure ahead of the turbine, which installation is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoid development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of, 1. providing within the turbine and steam generator control system, for response to a fast valving initiation signal input by bringing into effect preprogrammed jointly effected processes of, a. intercept valve closure effected fast enough to have a favorable effect on generator rotor first swing stability, and control valve repositioning plus intercept valve reopening so effected as to cause turbine driving power subsequent to generator rotor first forward swing to hold below a preset value that is less than the driving power that applied prior to the event that brought about development of the signal, b. runback of rate of steam production within the steam generator to a value that will cause termination of the discharge of steam through said power operated relief valves that will at first take place, with provision so that said runback is effected rapidly enough to avoid overheating of the reheater, 2. providing in a preprogrammed manner so that a fast valving signal is generated and transmitted aS an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 3
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted as an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 4
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted as an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 5
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted as an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 6
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted as an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 7
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted aS an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 8
Dependent Claim
40 words
providing in a preprogrammed manner so that a fast valving signal is generated and transmitted aS an input to the turbine and steam generator control system on the occurrence of certain types of events that endanger preservation of system stability.
Claim 9
Dependent Claim
36 words
The method of claim 1 wherein one of a plurality of pairs of coordinated preprogrammed processes of turbine and steam generator control will be selectively activated in dependence on the nature of the stability endangering event.
Claim 10
Dependent Claim
24 words
The method of claim 1 in which some but not all of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 11
Dependent Claim
21 words
The method of claim 1 in which half of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 12
Dependent Claim
22 words
The method of claim 1 in which one quarter of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 13
Dependent Claim
200 words
In a steam-electric installation incorporating a U.S. type once through boiler, one or more power operated valves that are arranged so that when opened they provide a path by which steam can by-pass from a point ahead of the turbine to the flash tank of said boiler, and from thence to the condenser, which valves are subject to the control ofa a control system which causes them to open when the pressure ahead of the valves exceeds a preset value which is less than that pressure that will cause discharge of steam through the turbine''s high pressure safety valves, and are also so controlled as to close when pressure falls to a preset value that exceeds the normal operating pressure of the turbine, which installation is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoid development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of,
Claim 14
Dependent Claim
200 words
In a steam-electric installation incorporating a U.S. type once through boiler, one or more power operated valves that are arranged so that when opened they provide a path by which steam can by-pass from a point ahead of the turbine to the flash tank of said boiler, and from thence to the condenser, which valves are subject to the control ofa a control system which causes them to open when the pressure ahead of the valves exceeds a preset value which is less than that pressure that will cause discharge of steam through the turbine''s high pressure safety valves, and are also so controlled as to close when pressure falls to a preset value that exceeds the normal operating pressure of the turbine, which installation is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoid development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of,
Claim 15
Dependent Claim
36 words
The method of claim 6 wherein one of a plurality of pairs of coordinated preprogrammed processes of turbine and steam generator control will be selectively activated in dependence on the nature of the stability endangering event.
Claim 16
Dependent Claim
24 words
The method of claim 6 in which some but not all of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 17
Dependent Claim
21 words
The method of claim 6 in which half of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 18
Dependent Claim
22 words
The method of claim 6 in which one quarter of the turbine''s control valves are rapidly closed by valve actuator oil dumping.
Claim 19
Dependent Claim
80 words
In a steam-electric installation which is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoId development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of,
Claim 20
Dependent Claim
80 words
In a steam-electric installation which is part of a power system which includes a plurality of prime mover driven generators, which generators are interconnected by a plurality of transmission circuits, the method of employing fast turbine valving as a way to avoId development of system instability as a consequence of stability endangering events of a type adapted to cause the generator of the said installation to experience a sudden at least momentary reduction of load, which comprises the steps of,
Claim 21
Dependent Claim
15 words
The process of claim 11, in which intercept valves in step (1), are fully closed.
Claim 22
Dependent Claim
21 words
The process of claim 11 in which intercept valve reopening is initiated within 0.1 second of completion of the closing process.
Claim 23
Dependent Claim
41 words
The process of claim 11 in which partial intercept valve reopening carried out in step (2) is effected with oil supplied from accumulators, and is terminated by operation of valves of cam operated type, with cam position determined by valve stroke.
Claim 24
Dependent Claim
42 words
The process of claim 11 in which fast partial intercept valve reopening, carried out in step 2, is effected by the transfer to the cylinder of each of the valve actuators, of a predetermined quantity of oil contained within a second cylinder.
Claim 25
Dependent Claim
74 words
The process of claim 11 in which control valves are repositioned in a manner adapted to bring into effect a preset sustained degree of partial closure, with provision so that said process of partial closure is accomplished rapidly enough, and to an extent sufficient, to prevent an increase in steam pressure ahead of the turbine''s intercept valves that would suffice to cause discharge of steam through safety valves located ahead of said intercept valves.
References Cited (Backward Citations)
US3515893A
Cited
US3421014A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |