Automatic control system and method for minimum flow valve in automatic pump merging and withdrawing process of gas turbine

Abstract

The invention discloses an automatic control system and method for a minimum flow valve in the automatic pump merging and withdrawing process of a gas turbine. The system comprises a large selection module, a subtraction module, a NOT block, a rate block, a small selection module, a first constant 99 module, a constant 100 module, a second constant 99 module, a plurality of switching selection modules and the like. The method comprises the steps that when a pump A is selected, the output value of a first switching selection module is 100, a second switching selection module outputs 100 downwards, and otherwise, the opening degree of an adjusting valve converted by an F (x) 11 module according to the inlet flow of the pump A is output; when the output of the minimum flow valve of the open A pump is' 1 ', a value subjected to speed limiting is output, and otherwise, a current value is output; otherwise, the rate is not limited to be the first constant 99 module; when the output of the minimum flow valve of the closed A pump is' 1 ', outputting a value subjected to speed limiting, otherwise, outputting a current value; otherwise, the rate is not limited to be the second constant 99 module. According to the invention, the minimum flow valve is kept at a proper opening degree when the pump of the unit is withdrawn or combined.

Description

Technical Field

[0001] The invention belongs to the field of intelligent control of gas generator sets, and in particular relates to an automatic control system and method for a minimum flow valve in a process of automatic pump paralleling and retreating of a gas engine. Background Art

[0002] Gas generator sets are new types of generator sets developed to meet the world's environmental protection requirements and the new market environment. They mainly use natural gas or harmful gases as fuel to convert energy and generate electricity. The working principle of gas generator sets is to convert gas (such as natural gas, biogas, etc.) into electrical energy. In a combined cycle gas turbine, the gas first enters the turbine steam generator (compressor) to produce high-pressure and high-temperature gas, and then enters the combustion chamber to mix with air and burn. The high-temperature and high-pressure gas drives the turbine to rotate, and then drives the generator to generate electricity. In a gas internal combustion engine, the gas burns directly in the cylinder, drives the piston to move, drives the crankshaft to rotate through the connecting rod, and finally drives the generator to generate electricity.

[0003] The unit load changes continuously during the peak load regulation process, especially during the automatic parallel connection and automatic withdrawal of the steam-driven feedwater pump. When the feedwater flow rate changes, the minimum flow valve must maintain an appropriate opening in real time to ensure that the pump can operate safely and controllably. If the minimum flow valve of the pump is not well controlled, it is easy to cause an unexpected shutdown of the unit. Especially when the unit is withdrawing or parallel connection, the feedwater flow rate is unstable, causing the minimum flow valve command to fluctuate back and forth, affecting the safe and stable operation of the unit. Summary of the invention

[0004] In order to solve the above-mentioned problems, the present invention provides an automatic control system and method for the minimum flow valve in the process of automatic pump connection and automatic pump disconnection of the gas turbine, so as to solve the problem that the minimum flow valve command fluctuates back and forth during the automatic pump connection and automatic pump disconnection of the steam-driven water supply pump of the gas turbine, thereby affecting the safe and stable operation of the unit, and to achieve the minimum flow valve maintaining an appropriate opening when the unit is disconnecting or connecting pumps.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: The automatic control system of the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine includes a large selection module, a subtraction module, a negation block, a rate block, a small selection module, a first constant 99 module, a constant 100 module, a second constant 99 module and multiple switching selection modules; The constant 100 module is connected to the third switch selection module input Y; the output of the F(x)11 module is respectively connected to the third switch selection module input N and the general election module input, the output of the third switch selection module is connected to the general election module input, the general election module output is connected to the fourth switch selection module input N, the subtraction module output is connected to the F(x)3 module input, the F(x)12 module output and the F(x)13 module output are connected to the general election module input; the output of the general election module is connected to the seventh switch selection module input N, and the first constant 99 module is connected to the seventh switch selection module input Y; the output of the negation block is respectively connected to the switch inputs of the fourth switch selection module and the seventh switch selection module, the output of the fourth switch selection module is connected to the input of the rate block, the output of the seventh switch selection module is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the first switch selection module; The output of the negation block is connected to the switch input of the fifth switching selection module and the sixth switching selection module respectively, and the output of the F(x)14 module is connected to the input N of the fifth switching selection module; the output of the subtraction module is connected to the input of the F(x)16 module; the output of the F(x)15 module and the output of the F(x)16 module are connected to the input of the small selection module; the output of the small selection module is connected to the input N of the sixth switching selection module, the second constant 99 module is connected to the input Y of the sixth switching selection module, the output of the fifth switching selection module is connected to the input of the rate block, the output of the sixth switching selection module is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the second switching selection module; the output of the second switching selection module is connected to the pump minimum flow valve instruction output.

[0006] A further improvement of the present invention is that the minimum flow valve instruction of pump A is connected to the first switching selection module input N, the fourth switching selection module input Y, and the fifth switching selection module input Y.

[0007] A further improvement of the present invention is that pump A has been selected to be connected to the switching input of the third switching selection module.

[0008] A further improvement of the present invention is that the inlet flow of pump A is connected to the input of the F(x)11 module, and the valve opening is adjusted according to the converted inlet flow of pump A.

[0009] A further improvement of the present invention is that the inlet flow of pump A is connected to the input of the F(x)12 module.

[0010] A further improvement of the present invention is that the output of the signal water supply set value is connected to the subtraction module input +, and the output of the water supply flow is connected to the subtraction module input -.

[0011] A further improvement of the present invention is that the switch signal for opening the minimum flow valve of pump A is respectively connected to the input of the negation block and the switch input of the first switching selection module.

[0012] A further improvement of the present invention is that the minimum flow valve of the A pump is connected to the input of the negation block and the switch input of the second switching selection module respectively.

[0013] A further improvement of the present invention is that the pump inlet flow is connected to the F(x)14 module input and the F(x)15 module input respectively.

[0014] The invention discloses a method for automatically controlling a minimum flow valve in a process of automatically paralleling and withdrawing a pump of a gas turbine. The method is based on the automatic control system of the minimum flow valve in a process of automatically paralleling and withdrawing a pump of a gas turbine, and comprises: When pump A is selected, the output value of the first switching selection module is 100, and the second switching selection module outputs 100 downward, otherwise the output is the valve opening calculated by the F (x) 11 module according to the inlet flow of pump A; when the output of the minimum flow valve of pump A is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise the rate is not limited to the first constant 99 module; when the output of the minimum flow valve of pump A is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise the rate is not limited to the second constant 99 module.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides an automatic control system and method for the minimum flow valve in the process of automatic pumping and pumping of a fuel engine, which adopts a control means of non-disturbance switching, and can accurately control the minimum flow valve when pumping or pumping, solves the problem of poor regulation of the total water supply flow of the unit, and realizes automatic control of the whole process of the unit water supply control system. The present invention adopts judgment conditions such as target load, unit load, A and B pump inlet flow, etc. to judge whether to open the minimum flow valve when pumping and pumping in an automatic mode. This method can meet the effective control of the minimum flow valve under different operating conditions of the unit, avoid fluctuations in the minimum flow valve command, and through this constraint condition, switch the minimum flow valve command given value to control the minimum flow valve opening, so that the minimum flow valve maintains an appropriate opening.

[0016] In summary, the automatic control system and method for the minimum flow valve during automatic pump connection and withdrawal of the gas turbine described in the present invention solves the problem of automatic control of the minimum flow valve during the process of pump connection and withdrawal of the unit, reduces the fluctuation of the minimum flow valve command, keeps the minimum flow valve at an appropriate opening, and realizes safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a design diagram of the logic configuration scheme of the present invention.

[0018] Figure 2 It is a structural schematic diagram of the minimum flow valve automatic control system in the process of automatic parallel pump withdrawal of the gas engine of the present invention. DETAILED DESCRIPTION

[0019] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0020] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0021] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0022] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0023] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0025] refer to Figure 1The present invention uses a combination of an alarm module, a greater than module, a logic or module, a logic and module, a logic not module, an analog disturbance-free switching selection module, etc., mainly based on the target load, the unit load, the A and B pump inlet flow rates and other judgment conditions, to judge whether to open the minimum flow valve when withdrawing the pump or combining the pumps in an automatic mode. This method can meet the effective control of the minimum flow valve under different operating conditions of the unit and avoid fluctuations in the minimum flow valve command. Through this constraint condition, the minimum flow valve command given value is switched to control the minimum flow valve opening, so that the minimum flow valve maintains an appropriate opening and the unit operates safely and stably.

[0026] The automatic control scheme of the minimum flow valve during the automatic connection and withdrawal of the gas turbine of the present invention mainly adopts the following technical methods, including: analog input: target load, unit load, A pump inlet flow, B pump inlet flow, A pump minimum flow valve instruction, A pump minimum flow valve feedback, pump A flow; switch input: A pump has been selected, withdrawal request to open the A pump minimum flow valve, pump A minimum flow valve in automatic mode; switch output: connection pump request to close the A pump minimum flow valve, close the A pump minimum flow valve.

[0027] The switch input A pump has been selected, indicating that pump A is selected for parallel pump or pump withdrawal operation. Pump A has been selected and the target load is greater than a certain value and the unit load is greater than a certain value and the inlet flow of pumps A and B is greater than a certain value after selection. If the four conditions are met at the same time, the RS trigger is triggered to request the closing of pump A minimum flow valve to be 1; the target load is greater than a certain value and the unit load is greater than a certain value and the inlet flow of pumps A and B is greater than a certain value after selection. The three conditions are ANDed and then negated, or the signal pump A has been selected to be negated, or the signal pump withdrawal request opens the minimum flow valve of pump A, or the opening and instruction of the minimum flow valve of pump A are both less than 5%. Any of the four conditions triggers the reset parallel pump request to close the minimum flow valve of pump A to be 0; the signal pump A minimum flow valve is in automatic mode and the parallel pump request closes the minimum flow valve of pump A, triggering the closing of the minimum flow valve of pump A to be 1; the minimum flow valve of pump A is in automatic mode and pump A has been selected to be negated and the flow of pump A is greater than a certain value, triggering the closing of the minimum flow valve of pump A to be 1. The two conditions are ORed, and any one of them is met to trigger the closing of the minimum flow valve of pump A to be 1.

[0028] Example 1 See also Figure 2 The embodiment provides an automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas engine, including a large selection module, a subtraction module, a negation block, a rate block, a small selection module, a first constant 99 module 8, a constant 100 module 9, an F(x)3 module, an F(x)11 module, an F(x)12 module, an F(x)13 module, an F(x)14 module, an F(x)15 module, an F(x)16 module and a plurality of switching selection modules.

[0029] The constant 100 module 9 is connected to the third switch selection module 3 input Y; the F(x)11 module output is respectively connected to the third switch selection module 3 input N and the general election module input, the third switch selection module 3 output is connected to the general election module input, the general election module output is connected to the fourth switch selection module 4 input N, the subtraction module output is connected to the F(x)3 module input, the F(x)12 module output and the F(x)13 module output are connected to the general election module input; the general election module output is connected to the seventh switch selection module 7 input N, the first constant 99 module 8 is connected to the seventh switch selection module 7 input Y; the output of the negation block is respectively connected to the switch inputs of the fourth switch selection module 4 and the seventh switch selection module 7, the output of the fourth switch selection module 4 is connected to the input of the rate block, and the output of the seventh switch selection module 7 is connected to the rate input of the rate block. , the output of the rate block is connected to the input Y of the first switching selection module 1; the output of the negation block is connected to the switch inputs of the fifth switching selection module 5 and the sixth switching selection module 6 respectively, and the output of the F(x)14 module is connected to the input N of the fifth switching selection module 5; the output of the subtraction module is connected to the input of the F(x)16 module; the output of the F(x)15 module and the output of the F(x)16 module are connected to the input of the small selection module; the output of the small selection module is connected to the input N of the sixth switching selection module 6, the second constant 99 module 10 is connected to the input Y of the sixth switching selection module 6, the output of the fifth switching selection module 5 is connected to the input of the rate block, the output of the sixth switching selection module 6 is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the second switching selection module 2; the output of the second switching selection module 2 is connected to the pump minimum flow valve instruction output.

[0030] In this embodiment, the minimum flow valve instruction of pump A is connected to the input N of the first switching selection module 1, the input Y of the fourth switching selection module 4, and the input Y of the fifth switching selection module 5.

[0031] In this embodiment, pump A has been selected to be connected to the switching input of the third switching selection module 3 .

[0032] In this embodiment, the inlet flow of pump A is connected to the input of module F(x)11, and the valve opening is adjusted according to the inlet flow of pump A. The inlet flow of pump A is connected to the input of module F(x)12.

[0033] In this embodiment, the output of the signal water supply set value is connected to the subtraction module input +, and the output of the water supply flow is connected to the subtraction module input -.

[0034] In this embodiment, the switch signal to open the minimum flow valve of pump A is connected to the input of the negation block and the switch input of the first switching selection module 1 respectively.

[0035] In this embodiment, the minimum flow valve of pump A is connected to the input of the negation block and the switch input of the second switching selection module 2 respectively.

[0036] In this embodiment, the pump inlet flow is connected to the F(x)14 module input and the F(x)15 module input respectively.

[0037] Example 2 See also Figure 2 The minimum flow valve automatic control system in the process of automatic parallel pump withdrawal of the gas engine provided in this embodiment includes a first switching selection module 1, a second switching selection module 2, a third switching selection module 3, a fourth switching selection module 4, a fifth switching selection module 5, a sixth switching selection module 6, a seventh switching selection module 7, a large selection module, a subtraction module, a negation block, a rate block, a small selection module, a first constant 99 module 8, a constant 100 module 9, a second constant 99 module 10, an F(x)3 module, an F(x)11 module, an F(x)12 module, an F(x)13 module, an F(x)14 module, an F(x)15 module and an F(x)16 module.

[0038] The minimum flow valve instruction of pump A is connected to the first switching selection module 1 input N, the fourth switching selection module 4 input Y, and the fifth switching selection module 5 input Y; pump A has been selected and connected to the switching input of the third switching selection module 3; the constant 100 module 9 is connected to the third switching selection module 3 input Y, the pump A inlet flow is connected to the F(x)11 module input, and the valve opening is converted according to the pump A inlet flow; the F(x)11 module output is respectively connected to the third switching selection module 3 input N and the general election module input, the third switching selection module 3 output is connected to the general election module input, the general election module output is connected to the fourth switching selection module 4 input N, the subtraction module output is connected to the F(x)3 module input, the pump A inlet flow is connected to the F(x)12 module input, the F(x)12 module output and the F(x)13 module output are connected to the general election module input; the output of the general election module is connected to the seventh switching selection module 7 input N, and the first constant 99 module 8 is connected to the seventh switching selection module 7 input Y. The switch signal to open the minimum flow valve of pump A is respectively connected to the input of the NOT block and the switching switch input of the first switching selection module 1, the output of the NOT block is respectively connected to the switching switch inputs of the fourth switching selection module 4 and the seventh switching selection module 7, the output of the fourth switching selection module 4 is connected to the input of the rate block, the output of the seventh switching selection module 7 is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the first switching selection module 1.

[0039] The minimum flow valve of pump A is connected to the input of the negation block and the switch input of the second switching selection module 2 respectively, the output of the negation block is connected to the switch input of the fifth switching selection module 5 and the sixth switching selection module 6 respectively, the pump inlet flow is connected to the F(x)14 module input and the F(x)15 module input respectively, and the F(x)14 module output is connected to the fifth switching selection module 5 input N; the output of the signal water supply set value is connected to the subtraction module input +, the output of the water supply flow is connected to the subtraction module input -, and the subtraction module output is connected to the F(x)16 module input; the F(x)15 module output and the F(x)16 module output are connected to the input of the small selection module; the output of the small selection module is connected to the sixth switching selection module 6 input N, the constant 99 module 10 is connected to the sixth switching selection module 6 input Y, the output of the fifth switching selection module 5 is connected to the input of the rate block, the output of the sixth switching selection module 6 is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the second switching selection module 2; the output of the second switching selection module 2 is connected to the pump minimum flow valve instruction output.

[0040] Example 2 See also Figure 2 The method for automatically controlling the minimum flow valve in the process of automatically paralleling and withdrawing the pump of the gas turbine provided in this embodiment includes: When pump A is selected, the output value of the first switching selection module 1 is 100, and the second switching selection module 2 outputs 100 downward, otherwise the output is the valve opening calculated by the F (x) 11 module according to the inlet flow of pump A; when the output of the minimum flow valve of pump A is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise, the rate is not limited to the first constant 99 module 8. When the output of the minimum flow valve of pump A is closed is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise, the rate is not limited to the second constant 99 module 10.

[0041] The present invention provides an automatic control system and method for the minimum flow valve in the process of automatic pump connection and withdrawal of a fuel engine. The control system mainly adopts the judgment conditions such as target load, unit load, and A and B pump inlet flows to judge whether to open the minimum flow valve when withdrawing or connecting pumps in an automatic mode. The method can meet the effective control of the minimum flow valve under different operating conditions of the unit and avoid fluctuations in the minimum flow valve command. Through this constraint condition, the minimum flow valve command given value is switched to control the minimum flow valve opening so that the minimum flow valve maintains an appropriate opening, allowing the minimum flow valve of the unit to be automatically controlled during the process of pump connection and withdrawal, reducing the fluctuation of the minimum flow valve command and achieving safe and stable operation of the unit.

[0042] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0043] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. Automatic control system for minimum flow valve during automatic pumping and unloading of gas turbine, characterized by: It includes a general selection module, a subtraction module, a negation block, a rate block, a small selection module, a first constant 99 module, a constant 100 module, a second constant 99 module and a plurality of switching selection modules; The constant 100 module is connected to the third switch selection module input Y; the output of the F(x)11 module is respectively connected to the third switch selection module input N and the general election module input, the output of the third switch selection module is connected to the general election module input, the general election module output is connected to the fourth switch selection module input N, the subtraction module output is connected to the F(x)3 module input, the F(x)12 module output and the F(x)13 module output are connected to the general election module input; the output of the general election module is connected to the seventh switch selection module input N, and the first constant 99 module is connected to the seventh switch selection module input Y; the output of the negation block is respectively connected to the switch inputs of the fourth switch selection module and the seventh switch selection module, the output of the fourth switch selection module is connected to the input of the rate block, the output of the seventh switch selection module is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the first switch selection module; The output of the negation block is connected to the switch input of the fifth switching selection module and the sixth switching selection module respectively, and the output of the F(x)14 module is connected to the input N of the fifth switching selection module; the output of the subtraction module is connected to the input of the F(x)16 module; the output of the F(x)15 module and the output of the F(x)16 module are connected to the input of the small selection module; the output of the small selection module is connected to the input N of the sixth switching selection module, the second constant 99 module is connected to the input Y of the sixth switching selection module, the output of the fifth switching selection module is connected to the input of the rate block, the output of the sixth switching selection module is connected to the rate input of the rate block, and the output of the rate block is connected to the input Y of the second switching selection module; The output of the second switching selection module is connected to the pump minimum flow valve command output.

2. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 1 is characterized in that: The minimum flow valve instruction of pump A is connected to the first switching selection module input N, the fourth switching selection module input Y, and the fifth switching selection module input Y.

3. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 2 is characterized in that: Pump A has been selected to be connected to the switching input of the third switching selection module.

4. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 3 is characterized in that: The inlet flow of pump A is connected to the input of F(x)11 module, and the valve opening is calculated according to the inlet flow of pump A.

5. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 4 is characterized in that: Pump A inlet flow is connected to the F(x)12 module input.

6. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 5 is characterized in that: The output of the signal water supply set value is connected to the subtraction module input +, and the output of the water supply flow is connected to the subtraction module input -.

7. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 6 is characterized in that: The switch signal to open the minimum flow valve of pump A is connected to the input of the negation block and the switch input of the first switching selection module respectively.

8. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 7 is characterized in that: The minimum flow valve of pump A is connected to the input of the negation block and the switching switch input of the second switching selection module respectively.

9. The automatic control system for the minimum flow valve in the process of automatic parallel pump withdrawal of the gas turbine according to claim 8, characterized in that: The pump inlet flow is connected to the F(x)14 module input and the F(x)15 module input respectively.

10. The method for automatically controlling the minimum flow valve during the automatic pump-back process of the gas turbine is characterized in that: The method is based on the minimum flow valve automatic control system in the process of automatic parallel pump withdrawal of the gas engine as described in claim 9, comprising: When pump A is selected, the output value of the first switching selection module is 100, and the second switching selection module outputs 100 downward, otherwise the output is the valve opening calculated by the F (x) 11 module according to the inlet flow of pump A; when the output of the minimum flow valve of pump A is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise the rate is not limited to the first constant 99 module; when the output of the minimum flow valve of pump A is "1", the value after rate limiting is output, otherwise the current value is output, and the output rate is the smaller value of the rate converted from the water supply set value and the actual water supply flow deviation value and the rate converted from the inlet flow of pump A; otherwise the rate is not limited to the second constant 99 module.

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