Patent US3928972A successfully refreshed from Google Patents.
US3928972A
Expired / Lapsed
US
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System and method for improved steam turbine operation
Assignee: Westinghouse Electric Corp
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Filing: 1973-02-13
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Granted: 1975-12-30
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Expires: 1993-02-13
Abstract
Abstract An electric power plant steam turbine system with programmed digital computer control in which excessive rotor stress and strain are prevented by developing control signals based upon a comparison between present calculated heat flow and a reference heat flow, the turbine operation being controlled by the control signals so that strain is maintained substantially at the maximum allowable value.
Inventors
- 👤 Robert L Osborne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:57
CPC Classifications
F; F01; F01D; F01D19/00; F01D19/02; F01K; F01K7/00; F01K7/16; F01K7/22; F01K7/24
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
73 words
An improved steam turbine system comprising: a. A steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a heat flow representation of present heat flow to said portion from a predetermined region in heat transfer relation to said portion; and c. means for controlling operation of said steam turbine as a function of said heat flow representation, whereby said thermal stress is controlled.
Claim 2
Dependent Claim
73 words
An improved steam turbine system comprising: a. A steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a heat flow representation of present heat flow to said portion from a predetermined region in heat transfer relation to said portion; and c. means for controlling operation of said steam turbine as a function of said heat flow representation, whereby said thermal stress is controlled.
Claim 3
Dependent Claim
32 words
The improved steam turbine system as described in claim 1, wherein said turbine portion is the turbine rotor, and said heat flow representation represeents heat flow to the surface of said rotor.
Claim 4
Dependent Claim
62 words
The improved steam turbine system as described in claim 2, comprising means for generating a difference representation representing the difference between a reference heat flow and said rotor heat flow, and means for generating a control signal as a function of said difference represeNtation, and wherein said controlling means controls operation of said steam turbine as a function of said control signal.
Claim 5
Dependent Claim
79 words
The improved steam turbine system as described in claim 3 comprising means for detecting steam temperature and steam pressure in a predetermined turbine region in heat transfer relation with said rotor and for generating therefrom a steam temperature signal and a steam pressure signal, and wherein said means for generating a representation of heat flow to said rotor performs the function of calculating heat flow to the rotor on the basis of said steam temperature and steam pressure signals.
Claim 6
Dependent Claim
53 words
The improved steam turbine system as described in claim 4, comprising means for determining rotor speed and generating a rotor speed signal, and wherein said means for generating said heat flow representation makes said heat flow calculation as a function of rotor speed when said system is controlling the speed of said turbine.
Claim 7
Dependent Claim
55 words
The improved steam turbine system as described in claim 5, comprising means for determining steam flow in said region and generating a steam flow signal, and wherein said means for generating a heat flow representation makes said heat flow calculation as a function of said steam flow signal when said system is controlling turbine load.
Claim 8
Dependent Claim
52 words
The improved steam turbine system as described in claim 3, wherein said means for generating a control signal incorporates means for limiting the rate of increase of said heat flow difference representation, and means for limiting said control signal as a function of present rotor surface strain and predicted rotor surface strain.
Claim 9
Dependent Claim
40 words
The improved steam turbine system as described in claim 5, wherein said means for generating a control signal generates a speed control signal and said means for controlling operation controls turbine speed when the system is in speed control operation.
Claim 10
Dependent Claim
42 words
The improved steam turbine system as described in claim 6, wherein said means for generating a control signal generates a steam flow signal and said means for controlling operation controls turbine steam flow when said turbine system is in load control operation.
Claim 11
Dependent Claim
63 words
The improved steam turbine system as described in claim 1, wherein said steam turbine has a plurality of portions subject to thermal stress, and comprising a plurality of means for generating representations of heat flow to respective ones of said portions and means for determining a controlling one of said heat flow representations as a function of which said steam turbine is controlled.
Claim 12
Dependent Claim
20 words
The improved steam turbine system as described in claim 10, wherein one of said additional portions is the turbine casing.
Claim 13
Dependent Claim
29 words
The improved steam turbine system as described in claim 1, wherein said turbine portion is the turbine casing, and said heat flow representation represents heat flow to said casing.
Claim 14
Dependent Claim
59 words
A control system for a steam turbine comprising: a. means for generating a representation of present time rate of change of temperature at the turbine rotor due to heat flow to said rotor from a predetermined region in heat transfer relation thereto; b. means for controlling steam flow to said turbine as a function of said heat flow representation.
Claim 15
Dependent Claim
59 words
A control system for a steam turbine comprising: a. means for generating a representation of present time rate of change of temperature at the turbine rotor due to heat flow to said rotor from a predetermined region in heat transfer relation thereto; b. means for controlling steam flow to said turbine as a function of said heat flow representation.
Claim 16
Dependent Claim
30 words
The control system for a steam turbine as described in claim 13, wherein said means for controlling said steam flow controls said steam flow so as to change turbine speed.
Claim 17
Dependent Claim
34 words
The control system for a steam turbine as described in claim 13, wherein said means for controlling steam flow controls said steam flow so as to change the load carried by said steam turbine.
Claim 18
Dependent Claim
37 words
The control system for a steam turbine as described in claim 14, wherein said means for controlling steam flow includes steam valve means positioned to determine steam flow through said turbine so as to control turbine speed.
Claim 19
Dependent Claim
37 words
The control system for a steam turbine as described in claim 15, wherein said means for controlling steam flow includes steam valve means positioned tO determine steam flow so as to control load delivered by the turbine.
Claim 20
Dependent Claim
103 words
A control system for controlling the operation of a steam turbine, comprising: a. means for determining the temperature difference between the steam temperature in a predetermined turbine region in heat transfer relation with the turbine rotor surface and the temperature of such turbine rotor surface; b. means for determining the rotor speed and steam flow through the predetermined region; c. means for generating a turbine operating representation as a function of said temperature difference, rotor speed and steam flow; and d. steam valve means operated by said operating representation for controlling steam flow to said turbine as a function of said operating representation.
Claim 21
Dependent Claim
103 words
A control system for controlling the operation of a steam turbine, comprising: a. means for determining the temperature difference between the steam temperature in a predetermined turbine region in heat transfer relation with the turbine rotor surface and the temperature of such turbine rotor surface; b. means for determining the rotor speed and steam flow through the predetermined region; c. means for generating a turbine operating representation as a function of said temperature difference, rotor speed and steam flow; and d. steam valve means operated by said operating representation for controlling steam flow to said turbine as a function of said operating representation.
Claim 22
Dependent Claim
55 words
The control system as described in claim 18 wherein said operating representation is a function of heat flow to the rotor surface, and comprising means for generating a heat flow limit representation as a function of a predetermined turbine thermal condition and for limiting the operation of said valve means in accordance with said limit.
Claim 23
Dependent Claim
97 words
The control system as described in claim 18, comprising a general purpose programmed digital computer which performs the following functions: a. generating a representation of the heat transfer coefficient at said rotor surface; b. generating a representation of present heat flow to said rotor surface as a function of said heat transfer coefficient and said temperature difference; c. generating a representation of the heat flow difference between a reference heat flow corresponding to maximum heat flow for allowable rotor strain and present heat flow; and d. generating said operating representation as a function of said difference representation.
Claim 24
Dependent Claim
16 words
The control system as described in claim 20, wherein said operating representation is a speed representation.
Claim 25
Dependent Claim
16 words
The control system as described in claim 20, wherein said operating representation is a load representation.
Claim 26
Dependent Claim
90 words
An improved method for operating a steam turbine, which turbine when operating has one or more portions thereof subject to thermal stress, comprising: a. generating a heat flow signal representing present heat flow to one of said portions from a predetermined region separate from and in heat transfer relation to said one portion; b. generating a control signal as a function of said heat flow signal; and c. controlling the operation of said steam turbine as a function of said control signal, thereby controlling thermal stress in said one portion.
Claim 27
Dependent Claim
90 words
An improved method for operating a steam turbine, which turbine when operating has one or more portions thereof subject to thermal stress, comprising: a. generating a heat flow signal representing present heat flow to one of said portions from a predetermined region separate from and in heat transfer relation to said one portion; b. generating a control signal as a function of said heat flow signal; and c. controlling the operation of said steam turbine as a function of said control signal, thereby controlling thermal stress in said one portion.
Claim 28
Dependent Claim
58 words
The improved method for operating a steam turbine as described in claim 23, wherein said one portion is the turbine rotor, and the step of generating said control signal comprises generating a difference signal representing the difference between a reference heat flow to the rotor corresponding to maximum allowable rotor strain and the heat flow to the rotor.
Claim 29
Dependent Claim
72 words
The improved method for operating a steam turbine as described in claim 24 wherein the step of generating said heat flow signal comprises determining steam temperature and pressure in a predetermined turbine region in heat transfer relation with the surface of said rotor; calculating heat flow to the rotor as a function of said determined steam temperature and pressure; and controlling turbine operation as a function of said calculated rotor heat flow.
Claim 30
Dependent Claim
44 words
The improved method for operating a steam turbine as described in claim 25, comprising determining rotor speed and calculating heat flow to the rotor as a function also of rotor speed, and controlling turbine speed as a function of the calculated rotor heat flow.
Claim 31
Dependent Claim
47 words
The improved method for operating a steam turbine as described in claim 25, comprising determining steam flow in said turbine region and calculating heat flow to the rotor as a function of steam flow, and controlling turbine load as a function of the calculated rotor heat flow.
Claim 32
Dependent Claim
28 words
The method fOr operating a steam turbine as described in claim 25, comprising limiting said control signal as a function of stress at other portions of said turbine.
Claim 33
Dependent Claim
58 words
The improved method for operating a steam turbine as described in claim 23, comprising generating a plurality of heat flow signals representing heat flow to a plurality of respective turbine portions subject to heat stress; selecting a limiting one of said heat flow signals; and generating said control signal as a function of said selected heat flow signal.
Claim 34
Dependent Claim
21 words
The improved method for operating a steam turbine as described in claim 23, wherein said one portion is the turbine casing.
Claim 35
Dependent Claim
23 words
The improved method for operating a steam turbine as described in claim 29, wherein one of said turbine portions is the turbine casing.
Claim 36
Dependent Claim
43 words
The improved method for operating a steam turbine as described in claim 23, further comprising limit signals representing rotor surface strain, accumulated fatigue damage, bore loadings, and casing strain, and limiting said control signal on the basis of one of said limit signals.
Claim 37
Independent Claim
86 words
A method for operating a steam turbine comprising: a. determining steam temperature in a predetermined turbine region separate from and in heat transfer relation with a preselected turbine rotor portion; b. generating a representation of present heat flow from said region to said turbine rotor portion as a predetermined function of said determined steam temperature; and c. controlling the steam turbine speed as a function of said heat flow representation and continuously controlling the heat flow to said rotor substantially corresponding to maximum allowable rotor strain.
Claim 38
Independent Claim
86 words
A method for operating a steam turbine comprising: a. determining steam temperature in a predetermined turbine region separate from and in heat transfer relation with a preselected turbine rotor portion; b. generating a representation of present heat flow from said region to said turbine rotor portion as a predetermined function of said determined steam temperature; and c. controlling the steam turbine speed as a function of said heat flow representation and continuously controlling the heat flow to said rotor substantially corresponding to maximum allowable rotor strain.
Claim 39
Dependent Claim
65 words
The method as described in claim 33, wherein the step of controlling the steam turbine speed comprises: a. generating a difference signal representing the difference between a reference heat flow corresponding to maximum allowable rotor strain, and heat flow to the rotor; and b. generating a control signal as a function of said difference signal, and controlling said steam turbine speed by said control signal.
Claim 40
Dependent Claim
45 words
The method as described in claim 34 further comprising generating limit signals representing limiting values of conditions selected from the group consisting of rotor surface strain, bore strain and casing strain, and limiting said control signal on the basis of one of said limit signals.
Claim 41
Independent Claim
49 words
A method for controlling a steam turbine comprising: a. generating a representation of current heat flow to the turbine rotor from a predetermined region in heat transfer relation to said rotor; and b. continuously controlling steam flow to said turbine as a function of said current heat flow representation.
Claim 42
Independent Claim
49 words
A method for controlling a steam turbine comprising: a. generating a representation of current heat flow to the turbine rotor from a predetermined region in heat transfer relation to said rotor; and b. continuously controlling steam flow to said turbine as a function of said current heat flow representation.
Claim 43
Dependent Claim
24 words
The method for control of a steam turbine as described in claim 36, comprising controlling said steam flow so as to change turbine speed.
Claim 44
Dependent Claim
29 words
The method for control of a steam turbine as described in claim 36, comprising controlling said steam flow so as to change the load carried by said steam turbine.
Claim 45
Dependent Claim
49 words
The method of controlling a steam turbine as described in claim 36, wherein said heat flow representation is generated as a function of the impulse chamber steam temperature (TI), the rotor surface temperature (TS), the heat transfer coefficient at the rotor surface (H), and the rotor surface area (A).
Claim 46
Dependent Claim
28 words
The method of controlling a steam turbine as described in claim 39, wherein H is determined as a function of rotor speed and steam flow past the rotor.
Claim 47
Dependent Claim
37 words
The method of controlling a steam turbine as described in claim 40, comprising determining at least one other turbine thermal condition, and limiting said steam flow to said turbine when said thermal condition exceeds a predetermined limit.
Claim 48
Dependent Claim
20 words
The method of controlling a steam turbine as described in claim 41, wherein said thermal condition is rotor surface strain.
Claim 49
Dependent Claim
19 words
The method of controlling a steam turbine as described in claim 41, wherein said thErmal condition is casing strain.
Claim 50
Independent Claim
95 words
A method for controlling steam turbine operation using a digital computer comprising: a. determining the temperature difference between the steam temperature in a predetermined turbine region in heat transfer relation with the turbine rotor surface and the temperature of such turbine rotor surface; b. determining the rotor speed and steam flow through said predetermined region; c. generating, with a general purpose programmed digital computer, a turbine operating representation as a function of said temperature difference, rotor speed and steam flow; and d. controlling steam flow to said turbine as a function of said operating representation.
Claim 51
Independent Claim
95 words
A method for controlling steam turbine operation using a digital computer comprising: a. determining the temperature difference between the steam temperature in a predetermined turbine region in heat transfer relation with the turbine rotor surface and the temperature of such turbine rotor surface; b. determining the rotor speed and steam flow through said predetermined region; c. generating, with a general purpose programmed digital computer, a turbine operating representation as a function of said temperature difference, rotor speed and steam flow; and d. controlling steam flow to said turbine as a function of said operating representation.
Claim 52
Dependent Claim
58 words
The digital computer control method as described in claim 44 wherein said operating representation is a function of heat flow to the rotor surface, and further comprising the step of generating a heat flow limit representation as a function of a predetermined turbine thermal condition and limiting said turbine steam flow in accordance with said heat flow limit.
Claim 53
Dependent Claim
99 words
The digital computer control method as described in claim 44, comprising performing the following steps with said general purpose programmed digital computer: a. generating a representation of the heat transfer coefficient at said rotor surface; b. generating a representation of present heat flow to said rotor surface as a function of said heat transfer coefficient and said temperature difference; c. generating a representation of the heat flow difference between a reference heat flow corresponding to maximum heat flow for allowable rotor strain, and present heat flow; and d. generating said operating representation as a function of said difference representation.
Claim 54
Dependent Claim
18 words
The digital computer control method as described in claim 46, wherein said operating representation is a speed representation.
Claim 55
Dependent Claim
18 words
A digital computer control method as described in claim 46, wherein said operating representation is a load representation.
Claim 56
Dependent Claim
118 words
An improved steam turbine system comprising: a. a steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a first representation of a first predetermined temperature condition at said portion; c. means for generating a second representation of a second predetermined temperature condition at a predetermined temperature region in heat transfer relation with said portion; d. means for utilizing said first and second representations for generating a representation of heat flow to said portion as a function of said first and second temperature conditions; and e. means for continuously controlling operation of said steam turbine as a function of said heat flow representation, whereby said thermal stress is controlled.
Claim 57
Dependent Claim
118 words
An improved steam turbine system comprising: a. a steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a first representation of a first predetermined temperature condition at said portion; c. means for generating a second representation of a second predetermined temperature condition at a predetermined temperature region in heat transfer relation with said portion; d. means for utilizing said first and second representations for generating a representation of heat flow to said portion as a function of said first and second temperature conditions; and e. means for continuously controlling operation of said steam turbine as a function of said heat flow representation, whereby said thermal stress is controlled.
Claim 58
Dependent Claim
112 words
An improved steam turbine system comprising: a. a steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a first representation of a first predetermined temperature condition at said portion; c. means for generating a second representation of a second predetermined temperature condition at a predetermined temperature region in heat transfer relation with said portion; d. means utilizing said first and second representations for generating a representation of the rate of change of said first predetermined temperature condition; and e. means for controlling operation of said steam turbine as a function of said rate of change representation, whereby said thermal stress is controlled.
Claim 59
Dependent Claim
112 words
An improved steam turbine system comprising: a. a steam turbine having a portion subject to thermal stress when said turbine is in operation; b. means for generating a first representation of a first predetermined temperature condition at said portion; c. means for generating a second representation of a second predetermined temperature condition at a predetermined temperature region in heat transfer relation with said portion; d. means utilizing said first and second representations for generating a representation of the rate of change of said first predetermined temperature condition; and e. means for controlling operation of said steam turbine as a function of said rate of change representation, whereby said thermal stress is controlled.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |