CN113565593B - Load self-adaptive control system for starting stage of split-shaft combined cycle unit - Google Patents
Load self-adaptive control system for starting stage of split-shaft combined cycle unit Download PDFInfo
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- CN113565593B CN113565593B CN202110798277.3A CN202110798277A CN113565593B CN 113565593 B CN113565593 B CN 113565593B CN 202110798277 A CN202110798277 A CN 202110798277A CN 113565593 B CN113565593 B CN 113565593B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D19/00—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith
- F01D19/02—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith dependent on temperature of component parts, e.g. of turbine-casing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/08—Cooling; Heating; Heat-insulation
- F01D25/12—Cooling
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
- F01K13/02—Controlling, e.g. stopping or starting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K13/00—General layout or general methods of operation of complete plants
- F01K13/02—Controlling, e.g. stopping or starting
- F01K13/025—Cooling the interior by injection during idling or stand-by
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
- F01K23/101—Regulating means specially adapted therefor
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/16—Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
Abstract
The application discloses a load self-adaptive control system for a starting stage of a split-shaft combined cycle unit, which is characterized by comprising a load control module, a main steam temperature rise rate protection module, a steam turbine metal temperature rise rate protection module, a steam turbine expansion difference change rate protection module and a steam turbine expansion difference protection module.
Description
Technical Field
The application belongs to the technical field of split-shaft combined cycle units, and particularly relates to a load self-adaptive control system for a starting stage of a split-shaft combined cycle unit.
Background
In split-shaft combined cycle unit start-up, it is generally divided into three phases: the first stage of gas turbine starts to turbine warm-up load, the second stage of turbine starts to raise load, and the third stage of unit load is raised to the minimum load required by the power grid.
In the third stage of the combined cycle unit starting process, the main steam regulating valve of the steam turbine is kept in a full-open state under the minimum pressure control mode and does not participate in load control of the steam turbine, the lifting of the load of the steam turbine completely follows the load of the gas turbine, namely, the load of the gas turbine is lifted, the generated high-temperature flue gas is increased, the quality and the flow of steam generated by the waste heat boiler are lifted, and the steam enters the steam turbine to lift the load of the steam turbine. Therefore, turbine load changes have a significant hysteresis as compared to the rapid response characteristics of the turbine load.
In the stage that the unit load rises to the minimum load required by the power grid, the gas turbine load is generally adjusted according to the starting state of the gas turbine so as to start the gas turbine, however, the influence of the change of the gas turbine load on the main steam parameters of the gas turbine has serious hysteresis, the phenomena of too fast main steam temperature rise, too fast metal temperature rise, large expansion difference of the gas turbine and the like are easy to occur by adjusting the gas turbine, the starting safety of the unit is greatly reduced, and when the phenomenon of large expansion difference and the like occurs in the gas turbine, the gas turbine needs to keep or reduce the current load, and after each parameter of the gas turbine is stable or reduced, the load is continuously increased. The start-up time and fuel costs of the unit will increase.
Disclosure of Invention
The application provides a load self-adaptive control system for a split-shaft combined cycle unit starting stage, which solves the problem of reducing the starting safety of the unit due to unbalanced load distribution of a gas turbine and a steam turbine in the split-shaft combined cycle unit starting stage by arranging a main steam temperature rise rate protection module, a steam turbine metal temperature rise rate protection module, a differential expansion change rate protection module and a differential expansion protection module, and realizes that the main steam temperature rise rate and the steam turbine metal temperature rise rate are effectively stabilized in a combined cycle unit starting third stage, namely the combined cycle unit starting stage, the differential expansion of the steam turbine is effectively reduced, the starting safety of the combined cycle unit is greatly improved, the starting time of the combined cycle unit is shortened, and the fuel cost is effectively reduced.
The technical scheme provided by the application is as follows: a load self-adaptive control system for a start-up phase of a split-shaft combined cycle unit comprises the following monitoring steps:
the load control module controls the load operation of the combined cycle unit when the combined cycle unit is started;
a main steam temperature rise rate protection module; the main steam temperature rise rate protection module regulates and controls the load control module according to the opening degree of the main steam temperature reduction water control valve; when the opening of the main steam temperature reduction water control valve reaches a first opening, the main steam temperature rise rate protection module regulates and controls the load control module to suspend the combined cycle unit from carrying out load rise operation; when the opening degree of the main steam temperature-reducing water control valve reaches the second opening degree, the main steam temperature-rising rate protection module releases the load control module to suspend the combined cycle unit to carry out load-rising operation;
the turbine metal temperature rise rate protection module regulates and controls the load control module according to the comparison of the turbine metal temperature rise rate and the turbine temperature rise safety margin; when the metal temperature rise rate of the steam turbine is larger than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module of the steam turbine regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the metal temperature rise rate of the steam turbine is smaller than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module of the steam turbine releases the load control module to suspend the combined cycle unit from carrying out load lifting operation;
the steam turbine expansion difference change rate protection module regulates and controls the load control module according to the value of the steam turbine expansion difference change rate; when the expansion difference change rate value of the steam turbine reaches a first set value, the expansion difference change rate protection module of the steam turbine regulates and controls the load control module to pause the load lifting operation of the combined cycle unit; when the expansion difference change rate value of the steam turbine is smaller than a first set value, the expansion difference change rate protection module of the steam turbine releases the load control module to suspend the load lifting operation of the combined cycle unit;
the steam turbine expansion difference protection module regulates and controls the load control module according to the comparison of the steam turbine expansion difference value and the steam turbine expansion difference safety margin; when the steam turbine expansion difference value reaches a first steam turbine expansion difference safety margin, the steam turbine expansion difference protection module regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the steam turbine expansion difference change rate is smaller than a second set value, the steam turbine expansion difference protection module releases the load control module to suspend the combined cycle unit from carrying out load lifting operation; when the steam turbine expansion difference value reaches a second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module regulates and controls the load control module to suspend the combined cycle unit to carry out load lifting operation, and when the steam turbine expansion difference value is smaller than the second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module releases the load control module to suspend the combined cycle unit to carry out load lifting operation.
The load control module takes the total load of the combined cycle unit as a control target, and the load control module automatically distributes the loads of the gas turbine and the steam turbine. In the process of starting the integral load lifting of the combined cycle unit, the load change rate is slower due to the following characteristic of the load of the steam turbine, and the load change rate is not directly controlled by the regulating valve. The load of the combustion engine is firstly lifted, and after the main steam parameter is lifted, the load of the steam turbine is lifted, at the moment, the lifting load rate of the combustion engine is reduced under the load control module of the combined cycle unit, so that the balance state that the integral lifting load rate of the combined cycle unit is a fixed value is achieved.
The change rate of the expansion difference of the steam turbine in the expansion difference change rate protection module of the steam turbine refers to the change value of the expansion difference of the steam turbine every ten minutes, and the heating speed of the steam turbine rotor and the cylinder body in the starting process is inconsistent, wherein the phenomenon is that the steam turbine rotor is heated and expanded first in the initial stage of starting, and the expansion difference rises; the temperature of the cylinder body of the steam turbine rises and the cylinder body expands in the middle period of starting, and the rise of expansion difference is gradually slowed down; the rotor is fully expanded in the later starting period, the cylinder body is continuously heated to expand, and the expansion difference is reduced.
The safety margin of the temperature rise of the steam turbine refers to the safety value of the metal temperature of the steam turbine cylinder body rising per minute.
The differential expansion safety margin of the steam turbine refers to the value of the safety clearance distance between the dynamic part and the static part of the steam turbine.
According to the application, the main steam temperature rise rate protection module, the steam turbine metal temperature rise rate protection module, the steam turbine expansion difference change rate protection module and the steam turbine expansion difference protection module are arranged to regulate and control the load rise operation of the combined cycle unit when the opening of the main steam temperature reduction water control valve reaches a first opening, namely the main steam temperature exceeds the temperature reduction water control range, so that the load rise operation of the combined cycle unit is suspended, and when the opening of the main steam temperature reduction water control valve is smaller than a second opening, the protection is released, the load rise operation of the combined cycle unit is performed again, and the load rise rate of the main steam is effectively stabilized; when the metal temperature rise rate of the steam turbine in the metal temperature rise rate protection module of the steam turbine is larger than the safety margin of the first steam turbine, the load rising operation of the combined cycle unit is suspended, and when the metal temperature rise rate of the steam turbine is smaller than the safety margin of the first steam turbine, the protection is removed, the load rising operation of the combined cycle unit is performed again, and the stability of the metal temperature of the steam turbine is effectively ensured;
when the value of the expansion difference change rate of the turbine in the expansion difference change rate protection module of the turbine reaches a first set value, namely the expansion speed of the turbine rotor is far higher than the expansion speed of the cylinder body, the load lifting operation of the combined cycle unit is suspended, and when the value of the expansion difference change rate of the turbine is smaller than the first set value, the protection is removed, the load lifting operation of the combined cycle unit is carried out again, the expansion speed of the turbine rotor and the expansion speed of the cylinder body are effectively alleviated, and the stability and the safety are improved;
when the expansion difference value of the steam turbine in the expansion difference protection module of the steam turbine reaches a first expansion difference safety margin of the steam turbine, the load lifting operation of the combined cycle unit is suspended, and when the expansion difference change rate of the steam turbine is smaller than a second set value, the protection is released;
when the expansion difference value of the steam turbine reaches the safety margin of the expansion difference of the second steam turbine, the load lifting operation of the combined cycle unit is suspended, and when the expansion difference value of the steam turbine is smaller than the expansion difference of the second steam turbine, the protection is relieved, the expansion difference of the steam turbine is effectively prevented from being overlarge, and the stability is improved.
Through the arrangement, in the stage that the unit load is increased to the minimum load required by the power grid, the main steam temperature increasing rate and the steam turbine metal temperature increasing rate are effectively stabilized, the expansion difference of the steam turbine is effectively reduced, the starting safety of the combined cycle unit is greatly improved, the starting time of the combined cycle unit is reduced, and the fuel cost is effectively reduced.
Further, the first opening is 100% of the opening of the main steam temperature reduction water control valve, and the second opening is less than 98% of the opening of the main steam temperature reduction water control valve.
Further, the safety margin of the temperature rise of the first turbine is 1 ℃/min.
Further, the first set value is 1mm/10min.
Further, the first turbine differential expansion safety margin is 8.5mm, the second set value is 0.1mm/10min, and the second turbine differential expansion safety margin is 9mm.
Through the numerical value setting, the safe starting of the combined cycle unit is effectively ensured, the safety performance is effectively improved, the regulation and control can be performed according to the actual starting condition, the flexibility is high, and the adaptability is strong.
The application has the beneficial effects that: the main steam temperature rise rate protection module, the steam turbine metal temperature rise rate protection module, the expansion difference change rate protection module and the expansion difference protection module are arranged, so that the problems of reduction of the starting safety of the unit due to unbalanced load distribution of the gas turbine and the steam turbine in the starting stage of the split-shaft combined cycle unit are solved, the main steam temperature rise rate and the steam turbine metal temperature rise rate are effectively stabilized in the stage that the load of the unit is increased to the minimum load required by a power grid, the expansion difference of the steam turbine is effectively reduced, the starting safety of the combined cycle unit is greatly improved, the starting time of the combined cycle unit is reduced, and the fuel cost is effectively reduced.
Drawings
FIG. 1 is a schematic diagram of a control system of the present application; FIG. 2 is a control logic diagram of a differential expansion protection module of the steam turbine according to the present application;
FIG. 3 is a logic diagram of the calculation of differential expansion rate of the steam turbine according to the present application;
FIG. 4 is a graph of the expansion and load-lifting rate of a steam turbine according to the present application.
The marks in the figure: a main steam temperature rise rate protection module 1; a metal temperature rise rate protection module 2 of the steam turbine; a steam turbine differential expansion change rate protection module 3; and a differential expansion protection module 4 of the steam turbine.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In order to facilitate an understanding of the present application by those skilled in the art, the present application will be described in further detail with reference to specific examples and drawings.
As shown in fig. 1 to 3, a load adaptive control system for a split-shaft combined cycle unit in a start-up phase according to an embodiment of the present application includes: the load control module controls the load operation of the combined cycle unit when the combined cycle unit is started;
a main steam temperature rise rate protection module 1; the main steam temperature rise rate protection module 1 regulates and controls the load control module according to the opening degree of a main steam temperature reduction water control valve; when the opening degree of the main steam temperature reduction water control valve reaches a first opening degree, the main steam temperature rise rate protection module 1 regulates and controls the load control module to suspend the combined cycle unit to carry out load rise operation; when the opening degree of the main steam temperature reduction water control valve reaches the second opening degree, the main steam temperature rise rate protection module 1 releases the load control module to suspend the combined cycle unit to carry out load rise operation;
the turbine metal temperature rise rate protection module 2 regulates and controls the load control module according to the comparison of the turbine metal temperature rise rate and the turbine temperature rise safety margin; when the metal temperature rise rate of the steam turbine is larger than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module 2 of the steam turbine regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the metal temperature rise rate of the steam turbine is smaller than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module 2 of the steam turbine releases the load control module to suspend the combined cycle unit from carrying out load lifting operation;
the steam turbine expansion difference change rate protection module 3 regulates and controls the load control module according to the value of the steam turbine expansion difference change rate; when the expansion difference change rate value of the steam turbine reaches a first set value, the expansion difference change rate protection module 3 of the steam turbine regulates and controls the load control module to suspend the load lifting operation of the combined cycle unit; when the expansion difference change rate value of the steam turbine is smaller than a first set value, the expansion difference change rate protection module 3 of the steam turbine releases the load control module to suspend the combined cycle unit to carry out load lifting operation;
the steam turbine expansion difference protection module 4 regulates and controls the load control module according to the comparison of the steam turbine expansion difference value and the steam turbine expansion difference safety margin; when the steam turbine expansion difference value reaches a first steam turbine expansion difference safety margin, the steam turbine expansion difference protection module 4 regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the steam turbine expansion difference change rate is smaller than a second set value, the steam turbine expansion difference protection module 4 releases the load control module to suspend the combined cycle unit from carrying out load lifting operation; when the steam turbine expansion difference value reaches a second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module 4 regulates and controls the load control module to suspend the combined cycle unit to carry out load lifting operation, and when the steam turbine expansion difference value is smaller than the second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module 4 releases the load control module to suspend the combined cycle unit to carry out load lifting operation.
The load control module takes the total load of the combined cycle unit as a control target, and the load control module automatically distributes the loads of the gas turbine and the steam turbine. In the process of starting the integral load lifting of the combined cycle unit, the load change rate is slower due to the following characteristic of the load of the steam turbine, and the load change rate is not directly controlled by the regulating valve. The load of the combustion engine is firstly lifted, and after the main steam parameter is lifted, the load of the steam turbine is lifted, at the moment, the lifting load rate of the combustion engine is reduced under the load control module of the combined cycle unit, so that the balance state that the integral lifting load rate of the combined cycle unit is a fixed value is achieved.
The change rate of the expansion difference of the steam turbine in the expansion difference change rate protection module of the steam turbine refers to the change value of the expansion difference of the steam turbine every ten minutes, and the heating speed of the steam turbine rotor and the cylinder body in the starting process is inconsistent, wherein the phenomenon is that the steam turbine rotor is heated and expanded first in the initial stage of starting, and the expansion difference rises; the temperature of the cylinder body of the steam turbine rises and the cylinder body expands in the middle period of starting, and the rise of expansion difference is gradually slowed down; the rotor is fully expanded in the later starting period, the cylinder body is continuously heated to expand, and the expansion difference is reduced.
The safety margin of the temperature rise of the steam turbine refers to the safety value of the metal temperature of the steam turbine cylinder body rising per minute.
The differential expansion safety margin of the steam turbine refers to the value of the safety clearance distance between the dynamic part and the static part of the steam turbine.
According to the application, load operation during starting of the combined cycle unit is regulated and controlled by arranging the main steam temperature rise rate protection module 1, the steam turbine metal temperature rise rate protection module 2, the steam turbine expansion difference change rate protection module 3 and the steam turbine expansion difference protection module 4, wherein when the opening of the main steam temperature reduction water control valve reaches a first opening, namely the main steam temperature exceeds a temperature reduction water control range, the load operation of the combined cycle unit is suspended, and when the opening of the main steam temperature reduction water control valve is smaller than a second opening, the protection is released, the load operation of the combined cycle unit is performed again, and the main steam temperature rise rate is effectively stabilized; when the metal temperature rise rate of the steam turbine in the metal temperature rise rate protection module 2 of the steam turbine is larger than the safety margin of the first steam turbine, the load rising operation of the combined cycle unit is suspended, and when the metal temperature rise rate of the steam turbine is smaller than the safety margin of the first steam turbine, the protection is removed, the load rising operation of the combined cycle unit is performed again, and the stability of the metal temperature of the steam turbine is effectively ensured;
when the expansion difference change rate value of the steam turbine in the steam turbine expansion difference change rate protection module 3 reaches a first set value, namely the expansion speed of the steam turbine rotor is far higher than the expansion speed of the cylinder body, the load lifting operation of the combined cycle unit is suspended, and when the expansion difference change rate value of the steam turbine is smaller than the first set value, the protection is removed, the load lifting operation of the combined cycle unit is carried out again, the expansion speed of the steam turbine rotor and the expansion speed of the cylinder body are effectively relaxed, and the stability and the safety are improved;
when the expansion difference value of the steam turbine in the expansion difference protection module 4 reaches the first expansion difference safety margin of the steam turbine, the load lifting operation of the combined cycle unit is suspended, and when the expansion difference change rate of the steam turbine is smaller than a second set value, the protection is released; when the expansion difference value of the steam turbine reaches the safety margin of the expansion difference of the second steam turbine, the load lifting operation of the combined cycle unit is suspended, and when the expansion difference value of the steam turbine is smaller than the expansion difference of the second steam turbine, the protection is relieved, the expansion difference of the steam turbine is effectively prevented from being overlarge, and the stability is improved.
Through the arrangement, in the stage that the unit load is increased to the minimum load required by the power grid, the main steam temperature increasing rate and the steam turbine metal temperature increasing rate are effectively stabilized, the expansion difference of the steam turbine is effectively reduced, the starting safety of the combined cycle unit is greatly improved, the starting time of the combined cycle unit is reduced, and the fuel cost is effectively reduced.
Further, the first opening is 100% of the opening of the main steam temperature reduction water control valve, and the second opening is less than 98% of the opening of the main steam temperature reduction water control valve.
Further, the safety margin of the temperature rise of the first turbine is 1 ℃/min.
Further, the first set value is 1mm/10min.
Further, the first turbine differential expansion safety margin is 8.5mm, the second set value is 0.1mm/10min, and the second turbine differential expansion safety margin is 9mm.
Through the numerical value setting, the safe starting of the combined cycle unit is effectively ensured, the safety performance is effectively improved, the regulation and control can be performed according to the actual starting condition, the flexibility is high, and the adaptability is strong.
The following table is the starting duration test data of the starting control system of the combined cycle unit and the starting control system of the existing combined cycle unit:
the data can obviously show that the starting time of the third stage of the combined cycle unit can be effectively shortened by adopting the starting control system of the combined cycle unit, so that the starting economy of the combined cycle unit is improved.
As is evident from the graph of the turbine expansion versus load-lifting rate that is shown in fig. 4, the combined cycle unit start control system uses the expansion of the cylinder at the time when the unit start enters the third stage as X. And obtaining the optimal load lifting rate of the unit as a Y value through a test, and obtaining a relation curve of the cylinder expansion X and the optimal load lifting rate Y. The lower limit of the X value is that the unit is stopped for a long time, and the cylinder body of the steam turbine expands when the cylinder body is completely cooled; the upper limit is the full expansion value of the turbine cylinder. The lower limit of the Y value is the optimal Y value when the lower limit of the X value passes the test; the upper limit is the maximum value under the unit load coordination control mode. In order to improve the economy of the hot start of the turbine, Y may be a maximum value when X > the turbine rotor full expansion value-the expansion difference safety margin value. When the expansion value of the turbine cylinder reaches a certain value, the turbine is considered not to have the phenomenon of large expansion difference, the load of the combined cycle unit can be rapidly improved, and the starting economy and safety of the combined cycle unit are effectively improved.
The application has the beneficial effects that: the main steam temperature rise rate protection module, the steam turbine metal temperature rise rate protection module, the expansion difference change rate protection module and the expansion difference protection module are arranged, so that the problems of reduction of the starting safety of the unit due to unbalanced load distribution of the gas turbine and the steam turbine in the starting stage of the split-shaft combined cycle unit are solved, the main steam temperature rise rate and the steam turbine metal temperature rise rate are effectively stabilized in the stage that the load of the unit is increased to the minimum load required by a power grid, the expansion difference of the steam turbine is effectively reduced, the starting safety of the combined cycle unit is greatly improved, the starting time of the combined cycle unit is reduced, and the fuel cost is effectively reduced.
It will be evident to those skilled in the art that the application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art. It should be noted that technical features not described in detail in the present application may be implemented by any prior art.
Claims (6)
1. The utility model provides a load self-adaptation control system of branch axle combined cycle unit start-up phase which characterized in that includes:
the load control module controls the load operation of the combined cycle unit when the combined cycle unit is started;
a main steam temperature rise rate protection module; the main steam temperature rise rate protection module regulates and controls the load control module according to the opening degree of the main steam temperature reduction water control valve; when the opening of the main steam temperature reduction water control valve reaches a first opening, the main steam temperature rise rate protection module regulates and controls the load control module to suspend the combined cycle unit from carrying out load rise operation; when the opening of the main steam temperature reduction water control valve reaches a second opening, the main steam temperature rise rate protection module releases the load control module to suspend the combined cycle unit from carrying out load lifting operation, and the second opening is the opening of the main steam temperature reduction water control valve which is smaller than 98%;
the turbine metal temperature rise rate protection module regulates and controls the load control module according to the comparison of the turbine metal temperature rise rate and the turbine temperature rise safety margin; when the metal temperature rise rate of the steam turbine is larger than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module of the steam turbine regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the metal temperature rise rate of the steam turbine is smaller than the first steam turbine temperature rise safety margin, the metal temperature rise rate protection module of the steam turbine releases the load control module to suspend the combined cycle unit from carrying out load lifting operation;
the steam turbine expansion difference change rate protection module regulates and controls the load control module according to the value of the steam turbine expansion difference change rate; when the expansion difference change rate value of the steam turbine reaches a first set value, the expansion difference change rate protection module of the steam turbine regulates and controls the load control module to pause the load lifting operation of the combined cycle unit; when the expansion difference change rate value of the steam turbine is smaller than a first set value, the expansion difference change rate protection module of the steam turbine releases the load control module to suspend the load lifting operation of the combined cycle unit;
the steam turbine expansion difference protection module regulates and controls the load control module according to the comparison of the steam turbine expansion difference value and the steam turbine expansion difference safety margin; when the steam turbine expansion difference value reaches a first steam turbine expansion difference safety margin, the steam turbine expansion difference protection module regulates and controls the load control module to suspend the combined cycle unit from carrying out load lifting operation, and when the steam turbine expansion difference change rate is smaller than a second set value, the steam turbine expansion difference protection module releases the load control module to suspend the combined cycle unit from carrying out load lifting operation; when the steam turbine expansion difference value reaches a second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module regulates and controls the load control module to suspend the combined cycle unit to carry out load lifting operation, and when the steam turbine expansion difference value is smaller than the second steam turbine expansion difference safety margin, the steam turbine expansion difference protection module releases the load control module to suspend the combined cycle unit to carry out load lifting operation.
2. The load adaptive control system for a split-shaft combined cycle unit start-up phase of claim 1, wherein the first opening is 100% of a main steam attemperation water control valve opening.
3. The load adaptive control system for the start-up phase of a split-shaft combined cycle unit of claim 1, wherein the first turbine temperature rise safety margin is 1 ℃/min.
4. The load adaptive control system for a split-shaft combined cycle unit start-up phase of claim 1, wherein the first set point is 1mm/10min.
5. The load adaptive control system for the start-up phase of a split-shaft combined cycle unit according to claim 1, wherein the first turbine differential expansion safety margin is 8.5mm, and the second set point is 0.1mm/10min.
6. The load adaptive control system for the start-up phase of a split-shaft combined cycle unit of claim 5, wherein the second turbine differential expansion safety margin is 9mm.
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| JP2000130108A (en) * | 1998-10-28 | 2000-05-09 | Toshiba Corp | Starting method for combined cycle power plant |
| CN110309585A (en) * | 2019-06-28 | 2019-10-08 | 华北电力科学研究院有限责任公司西安分公司 | A kind of implementation method of flexibility tuning controller |
| CN112833380A (en) * | 2021-01-08 | 2021-05-25 | 光大环保能源（江阴）有限公司 | High-low pressure bypass control system of intermediate reheating unit for power generation industry |
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| JP6037448B2 (en) * | 2013-03-15 | 2016-12-07 | 三菱日立パワーシステムズ株式会社 | Steam turbine power plant |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000130108A (en) * | 1998-10-28 | 2000-05-09 | Toshiba Corp | Starting method for combined cycle power plant |
| CN110309585A (en) * | 2019-06-28 | 2019-10-08 | 华北电力科学研究院有限责任公司西安分公司 | A kind of implementation method of flexibility tuning controller |
| CN112833380A (en) * | 2021-01-08 | 2021-05-25 | 光大环保能源（江阴）有限公司 | High-low pressure bypass control system of intermediate reheating unit for power generation industry |
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