Control method and system for correcting main steam pressure of gas turbine unit steam turbine valve opening degree

Abstract

The application discloses a control method and system for correcting main steam pressure of turbine valve opening degree of a gas unit, and the system comprises a first function x module, a first function t module, a second function t module and a first small selection module; the steam flow is connected to the first function x module, the first function x module is connected to the first function t module and the second function t module respectively, and then connected to the first small selection module and the basic main steam pressure. The method comprises the following steps: the steam flow is converted through the first function x module, the first function t module, the second function t module and the first small selection module, and the basic main steam pressure is obtained after conversion; when the temperature state is 1, the warm state impact turning pressure is output by the first switching module; when the temperature state is 0, the cold state impact turning pressure is output by the first switching module; when the heat state is 1, the hot state impact turning pressure is output by the second switching module; when the heat state is 0, the output of the first switching module is output by the second switching module; and finally, the turbine impact turning pressure is obtained at the output end of the second switching module.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of intelligent control of thermal power plants, and particularly relates to a control method and system for correcting the main steam pressure of a gas turbine valve opening degree. BACKGROUND

[0002] The main steam pressure of a gas-steam combined cycle unit is generally converted according to the evaporation capacity of a waste heat boiler. After the turbine is started and meshed (or connected to the grid), the main steam pressure of the combined cycle unit is maintained at the designed main steam pressure by the turbine and the bypass system. After the load of the unit changes or the steam system (external steam supply) changes, the original designed main steam pressure setting deviates from the actual operating requirement value. For example, if the set main steam pressure is greater than the current actual pressure value, the turbine will close the valve to maintain a higher main steam pressure; if the set main steam pressure is less than the current actual pressure value, the turbine will open the valve to maintain a lower main steam pressure, and when the valve is fully opened and still cannot meet the lower set pressure, the bypass system will intervene to assist in reducing the main steam pressure. In the process of rapid load change of the unit, the gas turbine has a much smaller thermal inertia than the waste heat boiler, and the deviation between the set main steam pressure and the current actual main steam pressure will increase frequently, resulting in frequent opening or closing of the turbine valve, and even the opening of the bypass to assist in pressure relief. SUMMARY

[0003] The purpose of the present application is to provide a control method and system for correcting the main steam pressure of a gas turbine valve opening degree, which adjusts the set value of the main steam pressure according to the change of the turbine valve opening degree, thereby stabilizing the turbine valve opening degree and avoiding the accidental opening of the bypass, realizing the energy-saving and efficient operation of the gas-steam combined cycle and eliminating the risk of anti-burning oil system fluctuation caused by valve fluctuation.

[0004] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0005] The control system for correcting the main steam pressure of a gas turbine valve opening degree comprises a first function x module, a first function t module, a second function t module, and a first small selection module.

[0006] The steam flow is connected to the first function x module, the first function x module is connected to the first function t module and the second function t module, and then connected to the first small selection module and the basic main steam pressure.

[0007] The present application further improves in that it further comprises a first switching module and a second switching module.

[0008] The cold state surge pressure is connected to the N terminal of the first switching module, the warm state surge pressure is connected to the Y terminal of the first switching module, the warm state is connected to the trigger terminal of the first switching module, the output terminal of the first switching module is connected to the N terminal of the second switching module, the hot state surge pressure is connected to the Y terminal of the second switching module, the hot state is connected to the trigger terminal of the second switching module, and the output terminal of the second switching module is connected to the turbine surge pressure.

[0009] The further improvement of the present application is that the first OR module and the first AND module are further included.

[0010] The single-shaft-steam turbine disengagement and the split-shaft-steam turbine disengagement are both connected to the first OR module, the output terminal of the first OR module is connected to the first AND module during the unit start-up process, and the output terminal of the first AND module is connected to the turbine non-output.

[0011] The further improvement of the present application is that a first order inertia module, a first subtraction module, a first less-than module, a first greater-than module and a first SR module are further included.

[0012] The turbine flow instruction is connected to the first order inertia module, the output terminal of the turbine flow instruction and the output terminal of the first order inertia module are both connected to the first subtraction module, the output terminal of the first subtraction module is connected to the first less-than module and the first greater-than module respectively, the output terminal of the first less-than module is connected to the S terminal of the first SR module, the output terminal of the first greater-than module is connected to the R terminal of the first SR module, and the output terminal of the first SR module is connected to the turbine flow instruction reduction.

[0013] The further improvement of the present application is that a second subtraction module, a delay disconnection module, a first addition module, a third switching module, a first NOT module, a fourth switching module and a rate module are further included.

[0014] The turbine surge pressure and the basic main steam pressure are both connected to the second subtraction module, the output terminal of the second subtraction module is connected to the Y terminal of the third switching module, the first constant zero is connected to the N terminal of the third switching module, the turbine non-output is connected to the trigger terminal of the delay disconnection module and the third switching module in sequence, the turbine non-output is connected to the first NOT module, the pressure switching rate is connected to the N terminal of the fourth switching module, the second constant zero is connected to the Y terminal of the fourth switching module, the turbine flow instruction reduction is connected to the trigger terminal of the fourth switching module, the third switching module, the first NOT module and the fourth switching module are all connected to the rate module, the rate module and the basic main steam pressure are both connected to the first addition module, and the output terminal of the first addition module is connected to the surge pressure correction pressure setting.

[0015] The further improvement of the present application is that a third subtraction module, a fourth subtraction module, a pure integral module and a second addition module are further included.

[0016] The front pressure of the steam turbine main valve and the pressure offset are connected to a second subtractor, the corrected post-turbine pressure and the second subtractor are connected to a third subtractor, the output end of the third subtractor, a third constant zero, and the unit combined cycle are connected to a pure integral module, the corrected post-turbine pressure and the pure integral module are connected to a second adding module, and the output end of the second adding module is connected to the effective pressure setting.

[0017] The control method for correcting the main steam pressure of the turbine valve opening of the gas unit is based on the control system for correcting the main steam pressure of the turbine valve opening of the gas unit, and includes the following steps.

[0018] The steam flow is converted into the basic main steam pressure through a first function x module, a first function t module, a second function t module and a first small selection module.

[0019] When the temperature state is 1, the first switching module outputs the warm state post-turbine pressure; when the temperature state is 0, the first switching module outputs the cold state post-turbine pressure; when the heat state is 1, the second switching module outputs the hot state post-turbine pressure; when the heat state is 0, the second switching module outputs the output of the first switching module; and finally, the output end of the second switching module obtains the turbine post-turbine pressure.

[0020] The further improvement of the present application further comprises:

[0021] When any one of the single-shaft gas turbine and the split-shaft gas turbine is not engaged or not connected to the grid, and the unit is started, the turbine is not in power.

[0022] The control mode of the turbine flow instruction reduction module includes: the turbine flow instruction is subjected to a first-order inertia module, a first subtractor, a first less-than module, a first greater-than module and a first SR module to obtain the turbine flow instruction reduction.

[0023] The further improvement of the present application further comprises:

[0024] When the turbine flow instruction reduction is 1, the output of the fourth switching module is a second constant zero; when the turbine flow instruction reduction is 0, the output of the fourth switching module is a pressure switching rate; the turbine post-turbine pressure is subtracted from the basic main steam pressure; when the delay disconnection module is 1, the output is the output of the second subtractor; when the delay disconnection module is 0, the output is a first constant zero; according to the state of the first non-module, the rate module output end is added to the basic main steam pressure, and the output end of the first adding module is the corrected post-turbine pressure setting.

[0025] The further improvement of the present application further comprises:

[0026] The front pressure of the steam turbine main valve and the pressure offset are calculated by a third subtraction module, the corrected pressure setting of the rush rotation pressure is calculated by subtracting the output end of the third subtraction module, when the unit has been combined circulation 1, the output end of the pure integral module is the fourth subtraction module, the corrected pressure setting of the rush rotation pressure is input to the second addition module, and the output end of the second addition module is the effective pressure setting.

[0027] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0028] The present application provides a control method and system for correcting the main steam pressure of the turbine valve opening of a gas unit, which solves the following two problems:

[0029] 1) When the rush rotation pressure and the main steam pressure setting deviation of the turbine are large during the cold or warm rush rotation process, after the turbine is engaged (or connected to the grid), the turbine valve is at risk of being closed due to maintaining a high main steam pressure setting;

[0030] 2) Through the main steam pressure setting self-adaptation of the unit variable load, the stable turbine valve opening and the full-closed bypass are realized, and the turbine throttling loss and the risk of oil pressure fluctuation of the anti-burning oil system are reduced.

[0031] In summary, the control method and system for correcting the main steam pressure of the turbine valve opening of the gas unit of the present application ultimately realize that the main steam pressure setting transmitted to the turbine in the control system is less than the current actual pressure, and the bypass setting pressure is greater than the current actual pressure. The stable turbine valve full opening and the full-closed bypass are achieved. When the current actual pressure suddenly increases due to turbine failure or other reasons, the bypass can quickly intervene and maintain the effect of the main steam pressure. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figures 1 to 6 It is a control system principle diagram for correcting the main steam pressure of the turbine valve opening of the gas unit

[0033] Figure 7 It is an effect diagram of the embodiment 3 of the present application.

[0034] Figure 8 It is an effect diagram of the embodiment 4 of the present application. DETAILED DESCRIPTION

[0035] In the following, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be essentially exemplary rather than limiting.

[0036] In the description of the application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0037] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0038] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection, or communication; it can be directly connected, or indirectly connected through intermediate medium, or the communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] In the present application, unless otherwise specifically defined and limited, the first feature "above" or "below" the second feature can include the direct contact between the first and second features, or the contact between the first and second features through another feature between them. Moreover, the first feature "above", "above" and "above" the second feature includes the first feature above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes the first feature above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0040] It should be understood that when used in the present specification and the appended claims, the terms "include" and "contain" indicate the presence of the described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0041] It should also be understood that the terms used in the specification and the following claims are for the purpose of describing particular embodiments and do not intend to limit the application. As used in the specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0042] It should be further understood that the term "and / or" used in the specification and the appended claims, means one or more of the associated listed items as well as all possible combinations of the items and includes the combinations.

[0043] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and some details may be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality may deviate due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0044] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0045] Embodiment 1

[0046] 1) Design a control method and system for correcting the main steam pressure of the turbine valve opening of the gas turbine unit, according to the change of the turbine valve opening, automatically adjust the set value of the main steam pressure, and then achieve stable turbine valve opening and avoid accidental opening of the bypass, realize energy-saving and efficient operation of the gas-steam combined cycle, and eliminate the risk of fuel oil system fluctuation caused by valve fluctuation.

[0047] 2) Control system principle for correcting the main steam pressure of the turbine valve opening of the gas turbine unit Figures 1 to 6 .

[0048] Figure 1 And Figure 2 Specifically includes: steam flow 001, first function x module 002, first function t module 003, second function t module 004, first small selection module 005, basic main steam pressure 006, cold state flushing pressure 007, warm state flushing pressure 008, warm state 009, hot state flushing pressure 010, hot state 011, first switching module 012, second switching module 013, turbine flushing pressure 014.

[0049] Figure 1 And Figure 2 The control strategy logic diagram includes:

[0050] Steam flow 001 is connected to first function x module 002, first function x module 002 is connected to first function t module 003 and second function t module 004 respectively, then connected to first less than module 005 and base main steam pressure 006.

[0051] Cold state run-up pressure 007 is connected to N terminal of first switch module 012, warm state run-up pressure 008 is connected to Y terminal of first switch module 012, warm state 009 is connected to trigger terminal of first switch module 012, output terminal of first switch module 012 is connected to N terminal of second switch module 013, hot state run-up pressure 010 is connected to Y terminal of second switch module 013, hot state 011 is connected to trigger terminal of second switch module 013, output terminal of second switch module 013 is connected to turbine run-up pressure 014.

[0052] Figure 3 And Figure 4 Specifically comprising: unit start-up process 015, single-shaft steam turbine not engaged 016, split-shaft steam turbine not connected to grid 017, first OR module 018, first AND module 019, steam turbine not generating power 020, steam turbine flow instruction 021, first order inertia module 022, first subtraction module 023, first less than module 024, first greater than module 025, first SR module 026, steam turbine flow instruction reduction 027.

[0053] Figure 3 And Figure 4 The control strategy logic diagram comprises:

[0054] Single-shaft steam turbine not engaged 016 and split-shaft steam turbine not connected to grid 017 are both connected to first OR module 018, output terminals of first OR module 018 and unit start-up process 015 are both connected to first AND module 019, output terminal of first AND module 019 is connected to steam turbine not generating power 020.

[0055] Steam turbine flow instruction 021 is connected to first order inertia module 022, output terminals of steam turbine flow instruction 021 and first order inertia module 022 are both connected to first subtraction module 023, output terminal of first subtraction module 023 is connected to first less than module 024 and first greater than module 025 respectively, output terminal of first less than module 024 is connected to S terminal of first SR module 026, output terminal of first greater than module 025 is connected to R terminal of first SR module 026, output terminal of first SR module 026 is connected to steam turbine flow instruction reduction 027.

[0056] Figure 5Specifically includes: basic main steam pressure 006, turbine run-up pressure 014, turbine non-output 020, pressure switching rate 032, turbine flow command reduction 027, first constant zero 034, second subtraction module 035, delay disconnection module 036, second constant zero 037, first addition module 038, third switching module 039, first non-module 040, fourth switching module 041, rate module 042, run-up pressure correction pressure set 043.

[0057] Figure 5 The control strategy logic diagram of the embodiment 1 comprises:

[0058] The turbine run-up pressure 014 and the basic main steam pressure 006 are connected to the second subtraction module 035, the output end of the second subtraction module 035 is connected to the Y end of the third switching module 039, the first constant zero 034 is connected to the N end of the third switching module 039, the turbine non-output 020 is connected to the delay disconnection module 036 and the trigger end of the third switching module 039 in turn, the turbine non-output 020 is connected to the first non-module 040, the pressure switching rate 032 is connected to the N end of the fourth switching module 041, the second constant zero 037 is connected to the Y end of the fourth switching module 041, the turbine flow command reduction 027 is connected to the trigger end of the fourth switching module 041, the third switching module 039, the first non-module 040 and the fourth switching module 041 are all connected to the rate module 042, the rate module 042 and the basic main steam pressure 006 are both connected to the first addition module 038, and the output end of the first addition module 038 is connected to the run-up pressure correction pressure set 043.

[0059] Figure 6 Specifically includes: run-up pressure correction pressure set 043, turbine main steam valve front pressure 045, pressure bias 046, unit has combined cycle 047, third subtraction module 048, fourth subtraction module 049, third constant zero 050, pure integral module 051, second addition module 052 and effective pressure set 053.

[0060] Figure 6 The control strategy logic diagram of the embodiment 2 comprises:

[0061] The turbine main steam valve front pressure 045 and the pressure bias 046 are both connected to the second subtraction 048, the run-up pressure correction pressure set 043 and the second subtraction 048 are both connected to the third subtraction 049, the output end of the third subtraction 049, the third constant zero 050 and the unit has combined cycle 047 are all connected to the pure integral module 051, the run-up pressure correction pressure set 043 and the pure integral module 051 are both connected to the second addition module 052, and the output end of the second addition module 052 is connected to the effective pressure set 053.

[0062] Embodiment 2

[0063] The application provides a control method for correcting main steam pressure of a gas turbine valve opening degree of a gas turbine unit, which comprises the following steps:

[0064] Figure 1 And Figure 2 The control modes are as follows:

[0065] The control mode of the basic main steam pressure 006 module comprises the following steps: the steam flow 001 is subjected to the first function x module 002, the first function t module 003, the second function t module 004 and the first small selection module 005, and the basic main steam pressure 006 is obtained after conversion.

[0066] The control mode of the turbine run-up pressure 014 module comprises the following steps: when the temperature state 009 is 1, the temperature state run-up pressure 008 is output by the first switch module 012; when the temperature state 009 is 0, the cold state run-up pressure 007 is output by the first switch module 012; when the hot state 011 is 1, the hot state run-up pressure 010 is output by the second switch module 013; when the hot state 011 is 0, the output of the first switch module 012 is output by the second switch module 013; and finally, the turbine run-up pressure 014 is obtained at the output end of the second switch module 013.

[0067] Figure 3 And Figure 4 The control modes are as follows:

[0068] The control mode of the turbine non-output 020 module comprises the following steps: when the single-shaft steam turbine is not engaged 016 or the split-shaft steam turbine is not connected to the grid 017, and any one module is 1 and the unit is started 015, the turbine non-output 020 is satisfied.

[0069] The control mode of the turbine flow instruction reduction 027 module comprises the following steps: the turbine flow instruction 021 is subjected to the first-order inertia module 022, the first subtraction module 023, the first less-than module 024, the first greater-than module 025 and the first SR module 026, and the turbine flow instruction reduction 027 is obtained after judgment.

[0070] Figure 5 The control modes are as follows:

[0071] The control mode of the post-turbo-charging pressure correction pressure set 043 module includes: when the turbine flow instruction reduction 027 is 1, the output of the fourth switch module 041 is the second constant zero 037; when the turbine flow instruction reduction 027 is 0, the output of the fourth switch module 041 is the pressure switch rate 032; the fourth switch module 041 is subtracted from the turbo-charging pressure 014 and the basic main steam pressure 006; when the delay cut-off module 036 is 1, the output is the output of the second subtraction module 035; when the delay cut-off module 036 is 0, the output is the first constant zero 034; according to the state of the first non-module 040, the output end of the rate module 042 is added to the basic main steam pressure 006, and the output end of the first addition module 038 is the post-turbo-charging pressure correction pressure set 043.

[0072] Figure 6 The control mode is as follows:

[0073] The control mode of the effective pressure set 053 module includes: the third subtraction module 048 is used to calculate the front pressure of the turbine main valve 045 and the pressure offset 046, the post-turbo-charging pressure correction pressure set 043 is subtracted from the output end of the third subtraction module 048, when the unit has a combined cycle 047 is 1, the output end of the pure integral module 051 is the output of the fourth subtraction module 049, the post-turbo-charging pressure correction pressure set 043 is input to the second addition module 052, and the output end of the second addition module 052 is the effective pressure set 053.

[0074] Embodiment 3

[0075] After the implementation and application of the technology of the present application, the gas turbine sliding pressure curve is as shown in Figure 7 , wherein 1 is coordinated to the high-pressure pressure set value; 2 is the high-pressure main steam pressure (DEH side); 3 is HP CTRL-V1 POSN MEAS; 4 is the high-pressure bypass steam control valve position feedback, according to the change of the turbine valve opening, the main steam pressure set value is automatically adjusted, and the high-pressure main steam pressure is always consistent with the set value.

[0076] Embodiment 4

[0077] After the implementation and application of the technology of the present application, the gas turbine sliding pressure curve is as shown in Figure 8 , wherein 1 is coordinated to the high-pressure pressure set value; 2 is the high-pressure main steam pressure (DEH side); 3 is HP CTRL-V1 POSN MEAS; 4 is the high-pressure bypass steam control valve position feedback, according to the change of the turbine valve opening, the main steam pressure set value is automatically adjusted, and the high-pressure main steam pressure is always consistent with the set value.

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A control system for correcting main steam pressure by adjusting the valve opening of a gas turbine unit, characterized in that, It includes the first function x module (002), the first function t module (003), the second function t module (004), the first small selection module (005), the first switching module (012), the second switching module (013), the first OR module (018), the first AND module (019), the first inertial module (022), the first subtraction module (023), the first less than module (024), the first greater than module (025), the first SR module (026), the second subtraction module (035), the delay disconnection module (036), the first addition module (038), the third switching module (039), the first NOT module (040), the fourth switching module (041), the rate module (042), the third subtraction module (048), the fourth subtraction module (049), the pure integration module (051), and the second addition module (052). Steam flow (001) is connected to the first function x module (002), the first function x module (002) is connected to the first function t module (003) and the second function t module (004) respectively, and then connected to the first small selection module (005) and the basic main steam pressure (006); The cold-state start-up pressure (007) is connected to the N terminal of the first switching module (012), the warm-state start-up pressure (008) is connected to the Y terminal of the first switching module (012), the warm-state pressure (009) is connected to the trigger terminal of the first switching module (012), the output terminal of the first switching module (012) is connected to the N terminal of the second switching module (013), the hot-state start-up pressure (010) is connected to the Y terminal of the second switching module (013), the hot-state pressure (011) is connected to the trigger terminal of the second switching module (013), and the output terminal of the second switching module (013) is connected to the turbine start-up pressure (014). The single shaft-turbine not engaged (016) and the split shaft-turbine not connected to the grid (017) are both connected to the first OR module (018). The output end of the first OR module (018) and the unit start-up process (015) are both connected to the first AND module (019). The output end of the first AND module (019) is connected to the turbine not outputting power (020). The turbine flow command (021) is connected to the first-order inertial module (022). The output of the turbine flow command (021) and the output of the first-order inertial module (022) are both connected to the first subtraction module (023). The output of the first subtraction module (023) is connected to the first less than module (024) and the first greater than module (025) respectively. The output of the first less than module (024) is connected to the S terminal of the first SR module (026). The output of the first greater than module (025) is connected to the R terminal of the first SR module (026). The output of the first SR module (026) is connected to the turbine flow command reduction (027). The turbine starting pressure (014) and the base main steam pressure (006) are both connected to the second subtraction module (035). The output of the second subtraction module (035) is connected to the Y terminal of the third switching module (039). The first constant zero (034) is connected to the N terminal of the third switching module (039). The turbine not outputting power (020) is connected in sequence to the trigger terminals of the delayed disconnection module (036) and the third switching module (039). The turbine not outputting power (020) is connected to the first non-module (040). The pressure switching rate (032) is connected to the fourth switching module. The N terminal of (041), the second constant zero (037) is connected to the Y terminal of the fourth switching module (041), the turbine flow command reduction (027) is connected to the trigger terminal of the fourth switching module (041), the third switching module (039), the first non-module (040), and the fourth switching module (041) are all connected to the rate module (042), the rate module (042) and the basic main steam pressure (006) are all connected to the first summing module (038), and the output terminal of the first summing module (038) is connected to the pressure setting after the stroke pressure correction (043). The turbine main steam valve pressure (045) and pressure offset (046) are both connected to the third subtraction module (048). The pressure setting after the start-up pressure correction (043) and the third subtraction module (048) are both connected to the fourth subtraction module (049). The output of the fourth subtraction module (049), the third constant zero (050), and the unit combined cycle (047) are all connected to the pure integration module (051). The pressure setting after the start-up pressure correction (043) and the pure integration module (051) are both connected to the second addition module (052). The output of the second addition module (052) is connected to the effective pressure setting (053).

2. A method for controlling main steam pressure by correcting the valve opening of a gas turbine unit, characterized in that, This method, based on the control system for correcting the main steam pressure by adjusting the turbine valve opening of a gas turbine unit as described in claim 1, includes: The steam flow rate (001) is converted into the basic main steam pressure (006) through the first function x module (002), the first function t module (003), the second function t module (004), and the first sub-selection module (005); When the temperature state (009) is 1, the first switching module (012) outputs the temperature state start-up pressure (008); when the temperature state (009) is 0, the first switching module (012) outputs the cold state start-up pressure (007); when the hot state (011) is 1, the second switching module (013) outputs the hot state start-up pressure (010); when the hot state (011) is 0, the second switching module (013) outputs the output of the first switching module (012); finally, the output of the second switching module (013) obtains the turbine start-up pressure (014). If either the single-shaft turbine is not engaged (016) or the split-shaft turbine is not connected to the grid (017), and either module is 1, and the unit is in the startup process (015), then the turbine is not outputting power (020). The control mode of the turbine flow command reduction (027) module includes: the turbine flow command (021) is judged by the first-order inertial module (022), the first subtraction module (023), the first less than module (024), the first greater than module (025) and the first SR module (026) to obtain the turbine flow command reduction (027); When the turbine flow command decrease (027) is 1, the output of the fourth switching module (041) is the second constant zero (037); when the turbine flow command decrease (027) is 0, the output of the fourth switching module (041) is the pressure switching rate (032); the turbine start-up pressure (014) is subtracted from the basic main steam pressure (006); when the delayed disconnection module (036) is 1, the output is the output of the second subtraction module (035); when the delayed disconnection module (036) is 0, the output is the first constant zero (034); according to the state of the first non-module (040), the output of the rate module (042) is added to the basic main steam pressure (006), and the output of the first addition module (038) is the pressure setting after the start-up pressure correction (043). The pressure (045) and pressure offset (046) before the main steam valve of the steam turbine are calculated by the third subtraction module (048). The pressure setting (043) after the start-up pressure correction is subtracted from the output of the third subtraction module (048). When the combined cycle (047) of the unit is 1, the output of the pure integral module (051) is the output of the fourth subtraction module (049). The pressure setting (043) after the start-up pressure correction and the pure integral module (051) are input to the second addition module (052). The output of the second addition module (052) is the effective pressure setting (053).

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