Steam turbine valve control system and method

Abstract

The invention discloses a steam turbine valve control system and method, and relates to the technical field of steam turbine power generation. The steam turbine valve control system includes a manual-automatic switching module for sending a first instruction; a first selection module for receiving the first instruction and outputting a speed control instruction according to the first instruction, wherein the speed control instruction includes a manual speed setting value and a default speed setting value; a second selection module for receiving a second instruction and selecting different valve opening instructions according to the second instruction; a control module for receiving the valve opening instruction and the speed control instruction and issuing a third instruction; and a third selection module for receiving a fourth instruction and selecting and outputting a third instruction and a fifth instruction according to the fourth instruction. Whether the valve is in an automatic or manual state, the ventilation valve can be opened in time, thereby ensuring the reliable operation of the steam turbine unit system.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine power generation, and in particular to a steam turbine valve control system and method. Background Art

[0002] The valve control of the steam turbine is to design the entire valve logic system of the steam turbine, adjust the valve opening and valve movement rate under various conditions, and play an important role in the safe operation of the steam turbine. The steam turbine valve control system is a system that controls the speed and power of the generator set by controlling the opening of the steam inlet valve of the steam turbine. The steam turbine valve control system is a closed-loop control system, which must be connected to the actuator, such as the main steam valve of the steam turbine, and perform switching actions, so that the instrumentation and control equipment of the main steam valve control system of the steam turbine can enter normal operation. When the steam turbine trips, if the ventilation valve is opened, the heat can be quickly taken away, but if the ventilation valve is not opened, the sealing pin on the high-pressure rotor will be cut off and the blades will fall off, resulting in a "sweeping" accident of the unit.

[0003] Therefore, it is very important to design the valve logic system of the steam turbine. During the start-up or shutdown process of the unit, if the operator does not put the valve into automatic control, any wrong operation will cause the high-pressure cylinder of the steam turbine to be blocked. However, the operator cannot manually control the high-exhaust ventilation valve, which will also cause some disadvantages. Special working conditions cannot be manually adjusted and interfered, reducing the flexibility of operation control. And when the steam turbine system trips or overspeeds, whether the steam turbine is in automatic or manual state, the logic design can ensure that the ventilation valve has a safe opening amount to avoid serious failures. Summary of the invention

[0004] In view of the above problems existing in the steam turbine valve control system, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is how to avoid the occurrence of malfunctions due to the failure of the high-pressure cylinder ventilation valve to open in time.

[0006] To solve the above technical problems, in a first aspect, the present invention provides the following technical solutions: a steam turbine valve control system, comprising a manual-automatic switching module for sending a first instruction; a first selection module for receiving the first instruction and outputting a speed control instruction according to the first instruction, wherein the speed control instruction includes a manual setting value for the rate and a default value for the rate; a second selection module for receiving the second instruction and selecting different valve opening instructions according to the second instruction; a control module for receiving the valve opening instruction and the speed control instruction and issuing a third instruction; a third selection module for receiving a fourth instruction and selecting to output a third instruction and a fifth instruction according to the fourth instruction; when the system trips or overspeeds, no matter what state the manual-automatic switching module is in, the third selection module outputs the fifth instruction to ensure that the valve opening is a set safety value.

[0007] As a preferred solution of the turbine valve control system described in the present invention, wherein: the valve opening instruction includes a first valve opening instruction and a second valve opening instruction; when the manual-automatic switching module is in manual state, the second selection module outputs the first valve opening instruction, and the first selection module outputs the manual setting value of the rate; when the manual-automatic switching module is in manual state and the turbine is connected to the grid at the same time, the second selection module delays the output of the second valve opening instruction, and the first selection module outputs the manual setting value of the rate; when the manual-automatic switching module is in automatic state, the second selection module outputs the first valve opening instruction, and the first selection module outputs the default value of the rate.

[0008] As a preferred solution of the turbine valve control system described in the present invention, it also includes: an actuator control system, including a positioner, which receives the third instruction and the fifth instruction, and realizes the actuator action by controlling the intake and exhaust of the amplifier; the amplifier includes an upper cylinder amplifier and a lower cylinder amplifier and is respectively connected to the two outlets of the positioner; the air-controlled valve includes an upper cylinder air-controlled valve and a lower cylinder air-controlled valve, the two ends of the upper cylinder air-controlled valve are respectively connected to the upper cylinder amplifier and the upper end of the valve cylinder, and the two ends of the lower cylinder air-controlled valve are respectively connected to the lower cylinder amplifier and the lower end of the valve cylinder.

[0009] As a preferred solution of the steam turbine valve control system of the present invention, wherein: the actuator control system also includes a filter pressure reducing valve, and the filter pressure reducing valve is used to supply air to the positioner, the amplifier, and the air control valve; when the positioner controls the lower cylinder amplifier to inlet air, the piston rod of the valve cylinder moves upward, and the upper cylinder amplifier exhausts air, and the valve is opened at this time; when the positioner controls the upper cylinder amplifier to inlet air, the piston rod of the valve cylinder moves downward, and the lower cylinder amplifier exhausts air, and the valve is closed at this time;

[0010] When the air source pressure is lost, the air control valve is closed and the valve cylinder remains stationary.

[0011] As a preferred solution of the turbine valve control system described in the present invention, wherein: the valve logic control system also includes a valve command module, a valve feedback module, a first deviation comparison module, and an alarm module; the valve command module is used to receive valve command signals, including the third command and the fifth command, and transmit them to the positioner; the valve feedback module is used to receive the valve feedback signal sent by the positioner; the first deviation comparison module is used to receive the valve command signal and the valve feedback signal and perform comparison and calculation. When the deviation between the two is greater than the preset deviation, the alarm module is activated.

[0012] As a preferred solution of the turbine valve control system described in the present invention, the valve logic control system also includes a second deviation comparison module, which is used to receive the valve command signal and the valve feedback signal and perform comparison and calculation. When the deviation between the two is greater than the preset deviation, the manual-automatic switching module switches to manual state.

[0013] As a preferred solution of the turbine valve control system described in the present invention, the valve logic control system also includes a quality judgment module for evaluating and judging the post-valve pressure value. When a quality defect occurs in the post-valve pressure value, the manual-automatic switching module switches to a manual state.

[0014] In the second aspect, the present invention also provides the following technical solutions: a method for controlling a high-exhaust ventilation valve of a steam turbine is applicable to the above-mentioned steam turbine valve control system, and the valve post-pressure value and the set value are input into the PID regulator to output the first valve opening instruction, and the first valve opening instruction is transmitted to the manual-automatic switching module; the manual-automatic switching module sends the first instruction to the first selection module, and the first selection module outputs the speed control instruction according to the first instruction; the second selection module receives the second instruction and chooses to output the first valve opening instruction or the second valve opening instruction; the control module receives the valve opening instruction and the speed control instruction and issues a third instruction; the third selection module receives the fourth instruction and chooses to output the third instruction or the fifth instruction; when the system trips or overspeeds, the third selection module outputs the fifth instruction to ensure that the valve opening is a safe opening.

[0015] As a preferred scheme of the turbine high-exhaust ventilation valve control method described in the present invention, wherein: when the manual-automatic switching module is in manual state, the second selection module outputs the first valve opening instruction, and the first selection module outputs the manual setting value of the rate; when the manual-automatic switching module is in manual state and the steam turbine generator is connected to the grid at the same time, the second selection module delays the output of the second valve opening instruction, and the first selection module outputs the manual setting value of the rate, so as to realize delayed valve closing; when the manual-automatic switching module is in automatic state, the second selection module outputs the first valve opening instruction, and the first selection module outputs the default value of the rate.

[0016] As a preferred solution of the steam turbine high exhaust ventilation valve control method of the present invention, when the deviation between the third instruction or the fifth instruction and the valve feedback signal is greater than a preset deviation, the system alarms;

[0017] When the deviation between the third instruction or the fifth instruction and the valve feedback signal is greater than a preset deviation, the valve is switched to manual mode; when a quality defect occurs in the pressure value after the valve, the valve is switched to manual mode.

[0018] The beneficial effects of the present invention are as follows: a safe 30% opening amount is introduced into the control of the high-exhaust ventilation valve of the steam turbine, ensuring that the high-exhaust ventilation valve can be opened in time regardless of whether the valve control is in manual or automatic state. Serious malfunctions caused by the failure to open the high-pressure cylinder ventilation valve in time are avoided. The system can implement valve adjustment under both automatic and manual conditions, greatly improving the flexibility and safety of the high-exhaust ventilation valve, and realizing the functions of slow closing when the turbine is connected to the grid and opening when the turbine trips. The deviation alarm and deviation lock in the logic effectively ensure the reliability of valve adjustment. The invention effectively ensures the three-dimensional control reliability of the high-exhaust ventilation valve of the steam turbine, reduces the occurrence of equipment misoperation and refusal to operate, and further ensures the stable operation of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 This is a schematic diagram of the valve logic control principle of the turbine valve control system.

[0021] Figure 2 This is a schematic diagram of the actuator control of the turbine valve control system.

[0022] In the figure: 1. manual-automatic switching module; 2. first selection module; 3. second selection module; 4. control module; 5. third selection module; 6. positioner; 7. amplifier; 7-1. upper cylinder amplifier; 7-2. lower cylinder amplifier; 8. air control valve; 8-1. upper cylinder air control valve; 8-2. lower cylinder air control valve; 9. valve cylinder; 10. filter pressure reducing valve; 11. valve instruction module; 12. valve feedback module; 13. first deviation comparison module; 14. alarm module; 15. second deviation comparison module; 16. quality judgment module. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0026] Reference Figure 1 , this embodiment provides a steam turbine valve control system, including a valve logic control system.

[0027] Specifically, the valve logic control system includes a manual-automatic switching module 1 for sending a first instruction; a first selection module 2 for receiving the first instruction and outputting a speed control instruction according to the first instruction, the speed control instruction including a manual set value for the rate and a default value for the rate; a second selection module 3 for receiving the second instruction and selecting different valve opening instructions according to the second instruction; a control module 4 for receiving the valve opening instruction and the speed control instruction and issuing a third instruction; a third selection module 5 for receiving the fourth instruction and selecting to output the third instruction and the fifth instruction according to the fourth instruction; when the system trips or overspeeds, no matter what state the manual-automatic switching module 1 is in, the third selection module 5 outputs the fifth instruction to ensure that the valve opening is a set safety value.

[0028] Furthermore, the valve opening instruction includes a first valve opening instruction and a second valve opening instruction; when the manual-automatic switching module 1 is in manual state, the second selection module 3 outputs the first valve opening instruction, and the first selection module 2 outputs the manual setting value of the rate; when the manual-automatic switching module 1 is in manual state and the turbine is connected to the grid at the same time, the second selection module 3 delays the output of the second valve opening instruction, and the first selection module 2 outputs the manual setting value of the rate; when the manual-automatic switching module 1 is in automatic state, the second selection module 3 outputs the first valve opening instruction, and the first selection module 2 outputs the default value of the rate.

[0029] Furthermore, when IN of the first selection module 2 is 1, the YES terminal value 100% value is output, that is, the default value of the rate; when IN of the first selection module 2 is 0, the NO terminal value is output, that is, the manual setting value of the rate.

[0030] When IN of the second selection module 3 is 1, the YES terminal value is output, that is, the second valve opening instruction is 0%, the valve closing instruction; when IN of the second selection module 3 is 0, the NO terminal value is output, that is, the first valve opening instruction from the PID regulator.

[0031] When IN of the third selection module 5 is 1, the YES terminal value is output, that is, the fifth instruction is output to open the valve by 30%; when IN of the third selection module 5 is 0, the NO terminal value is output, that is, the third instruction.

[0032] Among them, the post-valve pressure value is used as the PV value of the PID regulator, and the set value is used as the SV value. The two values ​​are input into the PID regulator to output the first valve opening instruction, and then enter the manual-automatic switching module 1. When the manual-automatic switching module 1 is in the automatic state, the first valve opening instruction can be directly output. At the same time, since the automatic signal is 1 in the automatic state, the first selection module 2 will output the YES end 100% value, that is, the default value of the rate. At this time, the rate of valve movement cannot be adjusted;

[0033] When the manual-automatic switching module 1 is in manual state, the automatic signal is 0, and the first selection module 2 will output the NO terminal value, that is, the valve movement rate is adjusted by the manual setting value of the rate. At the same time, the manual condition is triggered and enters the AND block together with the steam turbine power generation grid connection. The condition triggers the action and delays 60s to the second selection module 3, and selects the YES terminal 0% output, that is, when the steam turbine is in the grid-connected logic state, the valve is closed with a delay of 60s in the manual state.

[0034] When any of the turbine tripping and turbine overspeed protection OPC actions are triggered, a 3S pulse signal is sent to the third selection module 5, IN is 1, the third selection module 5 selects the YSE terminal 30% output, and the output instruction follows the control module 4 to realize the valve opening to 30%.

[0035] Preferably, the valve logic control system also includes a valve command module 11, a valve feedback module 12, a first deviation comparison module 13, and an alarm module 14; the valve command module 11 is used to receive valve command signals, including a third command and a fifth command, and transmit the third command and the fifth command to the positioner 6; the valve feedback module 12 is used to receive the valve feedback signal sent by the positioner 6; the first deviation comparison module 13 is used to receive the valve command signal and the valve feedback signal and perform comparative calculations. When the deviation between the two is greater than 5%, the alarm module 14 is activated to remind the operator that there may be problems with the valve action.

[0036] Preferably, the valve logic control system further includes a second deviation comparison module 15 for receiving the valve command signal and the valve feedback signal and performing comparison and calculation. When the deviation between the two is greater than 50%, the manual-automatic switching module 1 switches to the manual state.

[0037] Preferably, the valve logic control system further includes a quality judgment module 16 for evaluating and judging the pressure value after the valve. When the pressure value after the valve has a quality defect, the manual-automatic switching module 1 switches to a manual state.

[0038] As an optional embodiment, the steam turbine valve control system further includes an actuator control system.

[0039] Reference Figure 2 The actuator control system includes a positioner 6, an amplifier 7, an air control valve 8, a valve cylinder 9 and a filter pressure reducing valve 10. The positioner 6 receives the third instruction and the fifth instruction, and realizes the actuator action by controlling the air intake and exhaust of the amplifier 7; the amplifier 7 includes an upper cylinder amplifier 7-1 and a lower cylinder amplifier 7-2 and is respectively connected to the two outlets of the positioner 6; the air control valve 8 includes an upper cylinder air control valve 8-1 and a lower cylinder air control valve 8-2, the two ends of the upper cylinder air control valve 8-1 are respectively connected to the upper end of the upper cylinder amplifier 7-1 and the valve cylinder 9, and the two ends of the lower cylinder air control valve 8-2 are respectively connected to the lower end of the lower cylinder amplifier 7-2 and the valve cylinder 9.

[0040] Furthermore, the actuator control system also includes a filter pressure reducing valve 10, which is used to supply air to the positioner 6, the amplifier 7, and the air-controlled valve 8; when the positioner 6 acts on the lower cylinder amplifier 7-2 to inlet air, the piston rod of the valve cylinder 9 moves upward, and the upper cylinder amplifier 7-1 is exhausted, and the valve is opened at this time; when the positioner 6 acts on the upper cylinder amplifier 7-1 to inlet air, the piston rod of the valve cylinder 9 moves downward, and the lower cylinder amplifier 7-2 is exhausted, and the valve is closed at this time; when the air source pressure is lost, the air-controlled valve 8 is closed and the valve cylinder 9 remains stationary.

[0041] Among them, the compressed air is divided into five air paths after being decompressed and filtered by the filter pressure reducing valve 10. One path enters the positioner 6 as air supply regulation, two paths enter the upper cylinder amplifier 7-1 and the lower cylinder amplifier 7-2 respectively, and the other two paths enter the upper cylinder air control valve 8-1 and the lower cylinder air control valve 8-2 respectively. The first outlet of the positioner 6 is connected to the lower cylinder amplifier 7-2, and the second outlet is connected to the upper cylinder amplifier 7-1. When the air source pressure is normal, the upper cylinder air control valve 8-1 and the lower cylinder air control valve 8-2 are both opened for ventilation. When the positioner 6 controls the lower cylinder amplifier 7-2 to inlet air, the positioner 6 controls the upper cylinder amplifier 7-1 to exhaust air, and further the lower cylinder inlet air and the upper cylinder exhaust air, the valve is opened; when the positioner 6 controls the lower cylinder amplifier 7-2 to exhaust air, the positioner 6 controls the upper cylinder amplifier 7-1 to inlet air, and further the upper cylinder inlet air and the lower cylinder exhaust air, the valve is closed. When the air source pressure is lost, the upper cylinder air control valve 8-1 and the lower cylinder air control valve 8-2 are both closed, the upper cylinder and the lower cylinder do not inlet or exhaust air, and the valve remains in its original position.

[0042] Reference Figure 1 As an optional embodiment, this embodiment provides a method for controlling a steam turbine high exhaust ventilation valve.

[0043] Specifically, the post-valve pressure value and the set value are input into the PID regulator to output the first valve opening instruction, and the first valve opening instruction is transmitted to the manual-automatic switching module 1; the manual-automatic switching module 1 sends the first instruction to the first selection module 2, and the first selection module 2 outputs the speed control instruction according to the first instruction; the second selection module 3 receives the second instruction and selects to output the first valve opening instruction or the second valve opening instruction; the control module 4 receives the valve opening instruction and the speed control instruction and issues a third instruction; the third selection module 5 receives the fourth instruction and selects to output the third instruction or the fifth instruction;

[0044] Furthermore, when the system trips or overspeeds, the third selection module 5 outputs the fifth instruction to ensure that the valve opening is a safe opening. When the manual-automatic switching module 1 is in manual state, the second selection module 3 outputs the first valve opening instruction, and the first selection module 2 outputs the manual setting value of the rate; when the manual-automatic switching module 1 is in manual state and the steam turbine generator is connected to the grid at the same time, the second selection module 3 delays the output of the second valve opening instruction, and the first selection module 2 outputs the manual setting value of the rate to achieve delayed valve closing; when the manual-automatic switching module 1 is in automatic state, the second selection module 3 outputs the first valve opening instruction, and the first selection module 2 outputs the default value of the rate.

[0045] Among them, when the deviation between the valve command signal and the valve feedback signal is greater than 5%, the alarm module 14 is triggered to alarm; when the deviation between the valve command signal and the valve feedback signal is greater than 50%, the trigger condition enters the OR block and enters the manual-automatic switching module 1, and the valve is switched to manual; when the pressure value after the valve has a quality defect, it enters the quality judgment module 16, and after the condition is triggered, it enters the OR block and then enters the manual-automatic switching module 1, and the valve is switched to manual.

[0046] When the steam turbine is in the grid-connected logic state, the manual condition is triggered and enters the AND block together with the steam turbine power generation grid-connected. The condition triggers the action and delays for 60s to the IN in the second selection module 3. The YES terminal 0% output is selected and enters the control module 4. The rate selection is based on the output of the first selection module 2, and the output of the first selection module IN is 0, that is, the output rate manual setting value enters the control module 4. Directly input the valve instruction module. Realize the slow closing of the steam turbine grid-connected valve.

[0047] When the steam turbine is in any state of tripping or overspeed action, the turbine tripping and turbine OPC action are connected to the OR block together, and any condition is triggered, and after a 3S pulse signal, it enters the third selection module 5, and IN is 1 to trigger the selection of 30% full open. The valve is opened to 30%, and at the same time, the 30% signal will follow to the output end of the manual automatic switching module 1. After the pulse signal disappears, the valve can also be guaranteed to open to 30%.

[0048] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A steam turbine high exhaust ventilation valve control system, including a valve logic control system, characterized in that: include, A manual-automatic switching module (1), used for sending a first instruction; A first selection module (2) is used to receive the first instruction and output a speed control instruction according to the first instruction, wherein the speed control instruction includes a manual speed setting value and a default speed setting value; A second selection module (3), used for receiving a second instruction and selecting different valve opening instructions according to the second instruction; A control module (4), configured to receive the valve opening instruction and the speed control instruction and issue a third instruction; A third selection module (5), used for receiving a fourth instruction and selecting and outputting a third instruction and a fifth instruction according to the fourth instruction; When the system trips or overspeeds, no matter what state the manual-automatic switching module (1) is in, the third selection module (5) outputs the fifth instruction to ensure that the valve opening is a set safety value; The valve opening instruction includes a first valve opening instruction and a second valve opening instruction; When the manual-automatic switching module (1) is in a manual state, the second selection module (3) outputs the first valve opening instruction, and the first selection module (2) outputs the manual speed setting value; When the manual-automatic switching module (1) is in a manual state and the steam turbine is connected to the grid at the same time, the second selection module (3) outputs the second valve opening instruction with a delay, and the first selection module (2) outputs the manual speed setting value; When the manual-automatic switching module (1) is in the automatic state, the second selection module (3) outputs the first valve opening instruction, and the first selection module (2) outputs the default speed value.

2. The steam turbine high exhaust ventilation valve control system according to claim 1, characterized in that: Also included is an actuator control system, including, The positioner (6) receives the third instruction and the fifth instruction, and realizes the actuator action by controlling the air intake and exhaust of the amplifier (7); The amplifier (7) comprises an upper cylinder amplifier (7-1) and a lower cylinder amplifier (7-2) and is respectively connected to two outlets of the positioner (6); The air-controlled valve (8) comprises an upper cylinder air-controlled valve (8-1) and a lower cylinder air-controlled valve (8-2), wherein two ends of the upper cylinder air-controlled valve (8-1) are respectively connected to an upper cylinder amplifier (7-1) and an upper end of a valve cylinder (9), and two ends of the lower cylinder air-controlled valve (8-2) are respectively connected to a lower cylinder amplifier (7-2) and a lower end of the valve cylinder (9).

3. The steam turbine high exhaust ventilation valve control system according to claim 2, characterized in that: The actuator control system further comprises a filter pressure reducing valve (10), The filter pressure reducing valve (10) is used to supply air to the positioner (6), the amplifier (7), and the air control valve (8); When the positioner (6) controls the air intake of the lower cylinder amplifier (7-2), the piston rod of the valve cylinder (9) moves upward, and the upper cylinder amplifier (7-1) exhausts air, the valve opens at this time; When the positioner (6) controls the air intake of the upper cylinder amplifier (7-1), the piston rod of the valve cylinder (9) moves downward, and the lower cylinder amplifier (7-2) exhausts air, and the valve is closed at this time; When the air source pressure is lost, the air control valve (8) is closed and the valve cylinder (9) remains stationary.

4. The steam turbine high exhaust ventilation valve control system according to claim 3, characterized in that: The valve logic control system further comprises a valve instruction module (11), a valve feedback module (12), a first deviation comparison module (13), and an alarm module (14); The valve command module (11) is used to receive valve command signals, including the third command and the fifth command, and transmit them to the positioner (6); The valve feedback module (12) is used to receive the valve feedback signal sent by the positioner (6); The first deviation comparison module (13) is used to receive the valve command signal and the valve feedback signal and perform comparison and calculation, and when the deviation between the two is greater than a preset deviation, the alarm module (14) is activated.

5. The steam turbine high exhaust ventilation valve control system according to claim 4, characterized in that: The valve logic control system further comprises a second deviation comparison module (15) for receiving the valve command signal and the valve feedback signal and performing comparison and calculation. When the deviation between the two is greater than a preset deviation, the manual-automatic switching module (1) switches to a manual state.

6. The steam turbine high exhaust ventilation valve control system according to claim 5, characterized in that: The valve logic control system further comprises a quality judgment module (16) for evaluating and judging the post-valve pressure value. When a quality defect occurs in the post-valve pressure value, the manual-automatic switching module (1) switches to a manual state.

7. A method for controlling a high exhaust ventilation valve of a steam turbine, characterized in that: Applicable to the steam turbine high exhaust ventilation valve control system according to any one of claims 1 to 6, and Inputting the post-valve pressure value and the set value into the PID regulator to output a first valve opening instruction, and transmitting the first valve opening instruction to the manual-automatic switching module (1); The manual-automatic switching module (1) sends a first instruction to the first selection module (2), and the first selection module (2) outputs a speed control instruction according to the first instruction; The second selection module (3) receives the second instruction and selects to output the first valve opening instruction or the second valve opening instruction; The control module (4) receives the valve opening instruction and the speed control instruction and issues a third instruction; A third selection module (5) receives the fourth instruction and selects to output the third instruction or the fifth instruction; When the system trips or overspeeds, the third selection module (5) outputs the fifth instruction to ensure that the valve opening is a safe opening; When the manual-automatic switching module (1) is in a manual state, the second selection module (3) outputs the first valve opening instruction, and the first selection module (2) outputs the manual speed setting value; When the manual-automatic switching module (1) is in a manual state and the steam turbine generator is connected to the grid, the second selection module (3) delays outputting the second valve opening instruction, and the first selection module (2) outputs the manual rate setting value, thereby achieving delayed valve closing; When the manual-automatic switching module (1) is in the automatic state, the second selection module (3) outputs the first valve opening instruction, and the first selection module (2) outputs the default speed value; when the deviation between the third instruction or the fifth instruction and the valve feedback signal is greater than a preset deviation, the system alarms; When the deviation between the third instruction or the fifth instruction and the valve feedback signal is greater than a preset deviation, the valve is switched to manual mode; When the pressure value after the valve shows a quality defect, the valve is switched to manual.

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