Method for on-line adjustment of AP value of turbine governing valve servo valve

Abstract

The present application relates to a kind of steam turbine governing valve servo valve AP value on-line adjustment method, servo valve includes valve body, the valve sleeve of setting in the inner wall surface of valve body, respectively lock in the two ends of valve body and can with the two ends of valve sleeve be resisted first adjusting member and second adjusting member, on-line adjustment is carried out according to following steps: S1, the current AP value of servo valve is compared with standard AP value, when current AP value is less than standard AP value, step S2 is executed;When current AP value is greater than standard AP value, step S3 is executed, S2, first adjusting member is rotated and makes it separate from valve sleeve, then second adjusting member is rotated again, pushes valve sleeve and moves and makes it with first adjusting member be resisted, to increase the current AP value of servo valve, then jump to step S4, S3, second adjusting member is rotated and makes it separate from valve sleeve, then first adjusting member is rotated again to push valve sleeve and move until it with second adjusting member be resisted, to reduce the current AP value of servo valve, S4, end this on-line adjustment.The method can eliminate foreign matter and run oil risk.

Description

Technical Field

[0001] This invention relates to the field of nuclear power, and more specifically, to a method for online adjustment of the AP value of a steam turbine regulating valve servo valve. Background Technology

[0002] To eliminate control command deviations and achieve "deviation-free" regulation, the control system of the regulating steam valve of a 1000MW half-speed nuclear power plant introduces a servo valve AP value into the steam valve control logic. Obtaining the AP value requires the steam valve to be in a stable opening position, and the control system outputs a relatively stable comprehensive calculated AP value.

[0003] In servo valves, there is also a zero bias value, which differs from the AP value. "Zero bias" refers to the characteristic that, due to factors such as the structural dimensions, electromagnetic performance, hydraulic characteristics, and assembly of the valve components, the output flow rate is not zero when the input current is zero. The input current corresponding to zero output flow rate is the zero bias value of the servo valve. The zero bias value of the servo valve is its own control characteristic. When the input current exceeds the zero bias value, the servo valve spool deflects, causing the drive mechanism to receive oil. When the input current is less than the zero bias value, the servo valve spool deflects in the negative direction, causing the drive mechanism to discharge oil to the return line. The main influencing factor of the zero bias value comes from the servo valve itself. The AP value of the servo valve, on the other hand, is a comprehensive reflection of the servo valve itself, the drive mechanism, the valve body, and the control system. When regulating the valve stability, there is a stable deviation between the actual opening and the command. This stable deviation is the sum of the servo valve AP value, the jitter current, and the control command deviation.

[0004] The servo valve is a precision-controlled electro-hydraulic switching valve. Its zero bias value should not be adjusted too small or negative. When the zero bias value of the servo valve is too small or even negative, it will cause the regulating system that adjusts the AP value to become unstable. It will also cause the servo valve to lose its protective function of ensuring that the drive mechanism closes immediately in the event of a power failure. At the same time, the zero bias value should not be adjusted too large, as this will reduce the regulating sensitivity of the regulating system. Secondly, the AP value can also reflect the stability of the steam valve and its regulating system. Generally, the AP value is adjusted to the standard value before the unit starts up. In this invention, the standard value of AP is 20±5. Once the AP value changes suddenly or slowly during the operation of the unit, it proves that there is a fault or aging of the components in the regulating system. Because these components will cause changes in the AP value when they are faulty or aging, we cannot cover up the changes in the AP value caused by system faults when adjusting the AP value. This means that when changes in the AP value occur, it is necessary to check the faulty or aging components in time.

[0005] The AP value of a servo valve is affected by many factors. All factors that affect the valve opening deviation will affect the AP value of the servo valve, including the leakage of the servo valve itself, nozzle blockage, spool valve resistance, torque motor magnetic force and resistance, leakage of the drive mechanism, friction, spring force, buffer stroke, valve body friction and stroke, and comprehensive parameters of various control system components. In other words, all factors that affect the current when the valve is opened, such as leakage of the drive structure, motion resistance, hydraulic system blockage, resistance, capacitance, etc., will affect the AP value of the servo valve.

[0006] Since the most easily changed factors on-site are the various factors contained in the servo valve, and the servo valve is a must-inspect item for every maintenance - replacing the servo valve after it has been returned to the factory for repair, the various factors of the servo valve are regarded as a whole factor. The valve, drive mechanism, and control system components are regarded as a whole valve factor. The same servo valve will produce different AP values ​​with different valve bodies, and the same valve body will also produce different AP values ​​with different servo valves.

[0007] The current method for changing the AP value is to blindly test by replacing the servo valve. After each AP value test, if the requirements are not met, the servo valve is replaced until a servo valve that makes the AP value within the standard range is found. This method has the following disadvantages:

[0008] Firstly, each replacement takes a long time, and the valve oil system needs to be isolated each time, taking about 10 hours, which affects the operation of machinery and equipment such as the half-speed engine in the nuclear power plant.

[0009] At the same time, it is not possible to determine whether the AP value is qualified after each replacement. It needs to be determined through testing. This also makes the number of replacements uncertain. That is, if there are many servo valves with unqualified AP values ​​in this batch of servo valves to be replaced, the number of replacements will increase, which will increase the maintenance time and affect the availability of the unit and the unit uptime.

[0010] In addition, to ensure that there are enough servo valves for replacement, a large number of servo valves need to be prepared as a contingency plan, which also increases the storage capacity of servo valves and requires additional space for storing servo valves.

[0011] Furthermore, there is a risk of oil leakage every time the servo valve is replaced, which increases the risk of on-site management. It is necessary to have an emergency plan to prevent oil leakage during the replacement process. In addition, the servo valve is a precision control device, and the replaced servo valve must be carefully stored and protected from foreign objects. This also increases the risk of contamination of the servo valve, making it more susceptible to damage. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide an online adjustment method for the AP value of a steam turbine regulating valve servo valve, addressing the above-mentioned deficiencies of the prior art.

[0013] The technical solution adopted by this invention to solve its technical problem is: an online adjustment method for the AP value of a steam turbine regulating valve servo valve, wherein the servo valve includes a valve body, a valve sleeve disposed on the inner wall of the valve body, a first adjusting member and a second adjusting member respectively locked at both ends of the valve body and capable of abutting against both ends of the valve sleeve; the online adjustment is performed according to the following steps:

[0014] S1. Compare the current AP value of the servo valve with the standard AP value. If the current AP value is less than the standard AP value, proceed to step S2. If the current AP value is greater than the standard AP value, proceed to step S3.

[0015] S2. Rotate the first adjusting member to separate it from the valve sleeve, and then rotate the second adjusting member to push the valve sleeve to move so that it abuts against the first adjusting member, thereby increasing the current AP value of the servo valve, and then jump to step S4.

[0016] S3. Rotate the second adjusting member to separate it from the valve sleeve, and then rotate the first adjusting member to push the valve sleeve to move until it abuts against the second adjusting member, so as to reduce the current AP value of the servo valve.

[0017] S4. Run the servo valve once to obtain its new current AP value, and then compare the current AP value with a preset range;

[0018] When the current AP value exceeds the preset range, jump to step S1 to repeat the adjustment once;

[0019] When the current AP value is within the preset range, the online adjustment ends.

[0020] In some embodiments, in steps S2 and S3, the angle of rotation of the first adjusting member is no greater than 30° each time, and the angle of rotation of the second adjusting member is no greater than 30° each time.

[0021] In some embodiments, the sum of the angles at which the first adjusting member rotates multiple times in the same direction is no greater than 360°, and the sum of the angles at which the second adjusting member rotates multiple times in the same direction is no greater than 360°.

[0022] In some embodiments, the first and second adjusting members rotate by the same angle each time.

[0023] In some embodiments, when the absolute value of the difference between the AP value and the preset range is greater than 3, the first adjusting member or the second adjusting member adjusts by 20°-30° each time.

[0024] When the absolute value of the difference between the AP value and the preset range is less than or equal to 3, the first adjustment member or the second adjustment member adjusts by only 10° each time.

[0025] In some embodiments, when the current AP value is within the preset range, a zeroing test is also performed on the servo valve to confirm that the servo valve can gradually close when there is no current input; otherwise, the AP value is readjusted.

[0026] In some embodiments, after the valve sleeve abuts against the first adjusting member in step S2, or after the valve sleeve abuts against the second adjusting member in step S3, the first adjusting member and the second adjusting member are tightened with a tightening torque of 2.5 N·m.

[0027] In some embodiments, prior to step S1, the method further includes:

[0028] Confirm that the servo valve, its cooperating drive mechanism, and valve body are fault-free;

[0029] The servo valve is confirmed to have no input, including the drive mechanism being closed, the corresponding GFR system oil pump being shut down and depressurized, and the aviation connector not being connected. The online adjustment method for the AP value of a turbine regulating valve servo valve according to the present invention has the following advantages: the online adjustment method for the AP value of a turbine regulating valve servo valve can change the AP value of the servo valve within a controllable range; the adjustment method is simple; the adjustment time is significantly reduced; the risk of foreign object introduction and oil leakage is eliminated; and labor costs are reduced. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0031] Figure 1 This is a cross-sectional structural diagram of the servo valve in an embodiment of the present invention;

[0032] Figure 2 This is a flowchart illustrating an online adjustment method for the AP value of a steam turbine regulating valve servo valve according to the present invention. Detailed Implementation

[0033] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] The purpose of this invention is to find a method with fixed rules that does not affect the quality of on-site equipment and is operable on-site for maintenance, so as to achieve controllable adjustment of the AP value of the servo valve.

[0035] like Figure 1As shown, the servo valve includes a valve body 1, a slide valve 2, a valve sleeve 3, a first adjusting component 4, a second adjusting component 5, and a drive motor 6. The servo valve's oil ports include a pressure oil port P, a working oil port A, a working oil port B, a return oil port T, and a control oil port X. Port P is connected to the system's pressure oil, port A is connected to the hydraulic motor's pressure chamber, port B is blocked (this port is generally used for hydraulic motors with dual-sided oil inlet; ports A and B are connected to the upper and lower oil chambers of the hydraulic motor, respectively. Since the hydraulic motor in this project has a single-sided oil inlet and is closed by a spring, port B is useless and is blocked), port T is connected to the system's return oil, and port X is connected to the system's pressure oil (unlike port P, port X has a higher precision filter screen). The drive motor 6 is connected to the baffle 611 and the feedback rod 7. When the servo valve is running normally, the distance between the baffle 611 on both sides of the nozzle 61 and the nozzle 61 is equal, so that the oil discharge area of ​​the nozzles 61 on both sides is equal, and the oil pressure on both sides of the nozzle 61 is equal. That is, the oil pressure of the right oil chamber 21 of the slide valve 2 is equal to that of the left oil chamber 22. The P port of the slide valve 2 is not connected to the A port, and the T port is not connected to the A port. When the torque motor 6 receives the valve opening signal (positive current), the torque motor 6 drives the baffle 611 of the nozzle 61 to move to the left, making the distance between the left nozzle 61 and the baffle 611 smaller. The oil discharge area of ​​the nozzle 61 becomes smaller, the flow rate becomes smaller, and the oil pressure in front of the nozzle 61 becomes higher. On the other hand, the distance between the nozzle 61 and the baffle 611 on the opposite side (i.e., the right side) becomes larger, the oil discharge volume increases, and the pressure in front of the nozzle 61 becomes lower. Thus, the oil pressure in the left oil chamber 22 is greater than that in the left oil chamber 21. The slide valve 2 moves to the right, and the lower end of the feedback rod 7 also moves to the right until the distance between the baffle 611 and the two sides of the nozzle 61 is equal. The slide valve 2 stops moving to the right. Then, the P port and the A port are connected. The system pressure oil flows from the P port to the A port through the servo valve and enters the oil motor, pushing the oil motor to open the steam valve. When the feedback from the oil motor has opened to the required valve position, the drive motor 6 stops being powered. The slide valve 2, the baffle 611, and the feedback rod 7 return to the intermediate state, completing one adjustment cycle. When the torque motor 6 receives a valve-closing signal (negative current), the torque motor 6 drives the baffle 611 of the nozzle 61 to move to the right, making the distance between the right nozzle 61 and the baffle 611 smaller. This reduces the oil discharge area of ​​the nozzle 61, decreases the flow rate, and increases the oil pressure in front of the nozzle 61. Meanwhile, the distance between the nozzle 61 on the opposite side (i.e., the left side) and the baffle 611 increases, increasing the oil discharge and lowering the pressure in front of the nozzle. As a result, the oil pressure in the right oil chamber 22 is less than that in the left oil chamber 21. The slide valve 2 moves to the left, and the lower end of the feedback rod 7 also moves to the left until the distance between the baffle 611 and the two sides of the nozzle 61 is equal. The slide valve 2 stops moving to the left, and the T port and the A port are connected. The pressure oil in the hydraulic actuator flows from the A port to the T port through the servo valve and returns to the return oil pipeline. The hydraulic actuator discharges oil and closes the steam valve. When the feedback from the hydraulic actuator has closed to the required valve position, the drive motor 6 stops being powered, and the slide valve 2, the baffle 611, and the feedback rod 7 return to the intermediate state, completing another adjustment cycle.

[0036] During the overhaul of the control system, it was found that the zero offset value of the servo valve had a significant impact on the AP value, and that it changed with the change of the zero offset value. Figure 1 The diagram shows the structure of a servo valve. Before each servo valve is installed in the control system after being returned to the factory for maintenance, a fixed zero bias value is adjusted to ensure the safety and sensitivity of the control system. However, this zero bias value is an adjustable value. The position of the servo valve sleeve 3 is changed by adjusting the first adjusting member 4 and the second adjusting member 5 on both sides of the servo valve, thereby changing the AP value of the servo valve.

[0037] Factors affecting the AP value can be categorized into four main types: first, the mechanical structure of the servo valve itself, which also affects the zero bias value; second, the hydraulic system consisting of the servo valve and the drive mechanism; third, the control system, including the electrical parameters such as capacitance and resistance of each component; and fourth, the resistance of the hydraulic actuator driving the valve opening and closing.

[0038] Analyzing the above factors, apart from the servo valve itself, whose zero bias can be changed by adjusting its mechanical structure in real time, the remaining factors all have a long-term impact on the AP value. In other words, these factors are stable within a certain time period or at a certain moment, and their impact on the AP value remains unchanged. Therefore, these factors can be disregarded when adjusting or obtaining the required AP value.

[0039] Therefore, within a certain time period and at a certain moment, the change in the overall AP value of the control system directly originates from the mechanical structure of the servo valve, and its zero bias has the most direct and significant impact on the AP value. For a given servo valve, the overall AP value of the control system can be changed by adjusting its zero bias value.

[0040] Because the zero bias value of a servo valve is a control characteristic inherent to the servo valve itself, the main influencing factor originates from the servo valve itself. The most direct way to change the servo valve itself is to adjust its mechanical structure. The easiest part of the servo valve's mechanical structure to adjust is the screw. Adjusting the screw changes the servo valve's AP value. Therefore, the servo valve's AP value can be adjusted by adjusting the screw, the first adjusting member 4, and the second adjusting member 5. Based on this, combined with... Figure 2 As shown, the online adjustment method for the AP value of the turbine regulating valve servo valve in a preferred embodiment of the present invention includes the following steps:

[0041] S1. Compare the current AP value of the servo valve with the standard AP value. If the current AP value is less than the standard AP value, proceed to step S2; if the current AP value is greater than the standard AP value, proceed to step S3.

[0042] S2. Rotate the first adjusting member 4 to separate it from the valve sleeve 3, and then rotate the second adjusting member 5 to push the valve sleeve 3 to move so that it abuts against the first adjusting member 4, thereby increasing the current AP value of the servo valve, and then jump to step S4.

[0043] S3. Rotate the second adjusting member 5 to separate it from the valve sleeve 3, and then rotate the first adjusting member 4 to push the valve sleeve 3 to move until it abuts against the second adjusting member 5, so as to reduce the current AP value of the servo valve.

[0044] S4. End this online adjustment.

[0045] Therefore, when the valve sleeve 3 is pushed to move towards the first adjusting member 4, the AP value of the servo valve increases; when the valve sleeve 3 is pushed to move towards the second adjusting member 5, the AP value of the servo valve decreases. Thus, the online AP value adjustment method can change the AP value of the servo valve within a controllable range. The adjustment method is simple, the adjustment time is greatly reduced, and there is no need to remove or replace the servo valve to adjust the AP value of the servo valve, thereby eliminating the risk of foreign object introduction and oil leakage, and reducing labor costs.

[0046] Specifically, for every 10° adjustment of the first adjusting member 4 and the second adjusting member 5, the corresponding AP value can be changed by 1. That is, when the valve sleeve 3 is moved towards the first adjusting member 4, the AP value increases, and when the valve sleeve 3 is moved towards the second adjusting member 5, the AP value decreases, which facilitates bidirectional correction and adjustment.

[0047] In addition, in step S1, when the current AP value is equal to the standard AP value, the process jumps directly to step S4 without adjusting the first adjusting member 4 or the second adjusting member 5.

[0048] Typically, the zero offset of a servo valve is adjusted to 6.5mA. During the adjustment process, the first adjusting element 4 and the second adjusting element 5 are not allowed to be adjusted more than one turn to ensure that the zero offset does not become too large. Therefore, it is stipulated that when adjusting the AP value, the unidirectional rotation angle of the first adjusting element 4 and the second adjusting element 5 of the servo valve shall not exceed 360°, that is, the rotation range of the first adjusting element 4 and the second adjusting element 5 is 360° in both directions.

[0049] During normal adjustment, based on statistical adjustment data, the first adjusting member 4 and the second adjusting member 5 can be preset to rotate by a set angle. The AP value changes by one adjustment unit each time the set angle is rotated. Typically, referring to the above, the set angle is no greater than 10°, and can be 5°, 8°, 10°, etc., so that the first adjusting member 4 and the second adjusting member 5 rotate no more than 30° in a single rotation.

[0050] Based on previous experiments, it was concluded that for every 10° rotation of the first adjusting component 4 and the second adjusting component 5, the AP value will change by 1. Therefore, the adjustment margin of 360° in both directions can change the AP value by ±36, and the adjustment margin of the AP value is sufficient.

[0051] At the same time, after performing step S2 or S3 and before performing step S4, it is also necessary to tighten the first adjusting member 4 and the second adjusting member 5 with a tightening torque of 2.5 N·m.

[0052] Servo valves are precision control devices. When valve sleeve 3 is adjusted too much each time, the baffle, ball head, valve sleeve 3, valve core and nozzle on the servo valve will be "uncomfortable". That is, each adjustment should not be too much, but should be adjusted gradually in small increments. After each adjustment, the mobility test of the servo valve and steam valve should be carried out to ensure that each component is fully run-in and adapted after each adjustment. Therefore, the adjustment angle of the first adjusting component 4 and the second adjusting component 5 should not exceed 30° each time the AP value is adjusted.

[0053] To ensure that the adjusted servo valve's AP value conforms to the standard AP value, step S4 further includes: running the servo valve once to obtain its new current AP value, then comparing the current AP value with a preset range. If the current AP value exceeds the preset range, the process jumps to step S1 to repeat the adjustment. The online adjustment ends only when the current AP value is within the preset range. Specifically, when the absolute value of the difference between the AP value and the preset range is greater than a certain amount, if the absolute value of the difference is greater than 3, adjustments can be made in increments of 20-30°. If the absolute value of the difference is less than or equal to 3, adjustments are made in increments of 10° each time. For every 10° rotation, the current AP value of the servo valve is increased or decreased by 1 accordingly, thereby ensuring that the adjusted servo valve's AP value conforms to the standard AP value.

[0054] Manufacturers typically adjust the servo valve's zero bias value to 6.5mA before shipment. This leaves a small margin compared to a zero bias value of 0. When adjusting the AP value, if the adjustment is made beyond a certain value in the direction of decreasing the AP value, the servo valve's zero bias value may become negative. However, this unit requires the servo valve's zero bias value to be positive to ensure smooth valve closure or continuity between the servo valve's return oil and pressure oil in the event of a power outage due to unit malfunctions. Therefore, after adjusting the AP value, a zeroing test is performed. This involves opening the valve to a certain degree, disconnecting the aviation connector, simulating a situation where there is no current input to the servo valve, and checking that the valve opening should slowly close to zero.

[0055] Before executing step S1, it is also necessary to confirm whether each structure can operate normally. Specifically, it is necessary to confirm that the servo valve and its cooperating drive mechanism and valve body are fault-free.

[0056] By conducting valve tests during unit downlink, curves are reviewed to determine if any abnormal changes occur in each piece of equipment after operation, and to assess the health status of components in the steam valves, drive mechanisms, and control systems. For example, if the drive mechanism has had refurbished or replaced parts, or if an ATT test was conducted during downlink and the curve confirmed no abnormalities, or if valve body 1 has undergone a full inspection, or if an ATT test was conducted during downlink and the curve confirmed no abnormalities, the unit valve test is a specialized test performed on the valves based on their adjustment characteristics. During the test, the relationship between the valve opening curve and time can be measured, along with parameters such as the servo valve AP value, steam valve opening time, closing time, and fast closing time. These parameters can be used to determine if there are specific faults in the steam valves and control systems. Furthermore, by analyzing the operating status of the steam valves and their control systems during operation, specific defects in the servo valves, steam valves, and control systems can be identified.

[0057] Furthermore, since servo valves are precision electro-hydraulic conversion and adjustment devices with many control characteristics, special tools are required to perform various tests on the servo valves to obtain curves or parameters such as pressure gain, flow gain, leakage, and zero deviation, and to determine that all data of the servo valve are within the standard range. These tasks cannot be performed on-site during maintenance. In addition, to ensure the stability, sensitivity, and reliability of the control system, the servo valve spare parts must be replaced during each maintenance. Therefore, before adjusting the AP value, it is only necessary to check the curve of the servo valve's return-to-factory maintenance test to confirm that the servo valve has passed the maintenance.

[0058] Confirming no input, including the drive mechanism being closed, the corresponding GFR system oil pump being shut down and depressurized, and the aviation plug not being connected, ensures that the adjustment of the servo valve AP value is carried out smoothly.

[0059] In summary, the method for adjusting the AP value of the servo valve online has the following innovative aspects:

[0060] Firstly, this adjustment method can control the AP value of the servo valve with data, and has the characteristic of high consistency between the calculated adjustment value and the actual measured value, which makes the maintenance time controllable and reduces the uncontrollability of the maintenance period.

[0061] Secondly, this adjustment method can achieve online adjustment of the AP value without having to disassemble and replace the servo valve to adjust the AP value, eliminating the risk of foreign object introduction and oil leakage in the control system, minimizing the impact on the control system, and at the same time not reducing the function and precision control capability of the servo valve, thus reducing adverse effects on the servo valve.

[0062] In addition, this adjustment method will not cover up defects in other equipment of the valve and control system. When the AP value changes, it means that there are defects in other equipment of the valve and control system, so the defective equipment can be identified in time.

[0063] Understandably, the above-mentioned technical features can be used in any combination without restriction.

[0064] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for online adjustment of the AP value of a servo valve in a steam turbine regulating valve, wherein the servo valve comprises a valve body (1), a valve sleeve (3) disposed on the inner wall of the valve body (1), a first adjusting member (4) and a second adjusting member (5) respectively locked to both ends of the valve body (1) and capable of abutting against both ends of the valve sleeve (3); characterized in that, Follow these steps to make online adjustments: S1. Compare the current AP value of the servo valve with the standard AP value. If the current AP value is less than the standard AP value, proceed to step S2. If the current AP value is greater than the standard AP value, proceed to step S3. S2. Rotate the first adjusting member (4) to separate it from the valve sleeve (3), and then rotate the second adjusting member (5) to push the valve sleeve (3) to move so that it abuts against the first adjusting member (4) to increase the current AP value of the servo valve, and then jump to step S4. S3. Rotate the second adjusting member (5) to separate it from the valve sleeve (3), and then rotate the first adjusting member (4) to push the valve sleeve (3) to move until it abuts against the second adjusting member (5) to reduce the current AP value of the servo valve; S4. Run the servo valve once to obtain its new current AP value, and then compare the current AP value with a preset range; When the current AP value exceeds the preset range, jump to step S1 to repeat the adjustment once; When the current AP value falls within the preset range, the online adjustment ends. When the current AP value is within the preset range, a zeroing test is also performed on the servo valve to confirm that the servo valve can gradually close when there is no current input; Otherwise, readjust the AP value; For every 10° adjustment of the first adjusting member (4) and the second adjusting member (5), the corresponding AP value changes by 1. That is, when the valve sleeve (3) is moved toward the first adjusting member (4), the AP value increases, and when the valve sleeve (3) is moved toward the second adjusting member (5), the AP value decreases, which facilitates bidirectional correction and adjustment. When the absolute value of the difference between the AP value and the preset range is greater than 3, the first adjusting member (4) or the second adjusting member (5) adjusts by 20°-30° each time; When the absolute value of the difference between the AP value and the preset range is less than or equal to 3, the first adjusting member (4) or the second adjusting member (5) adjusts by only 10° each time.

2. The method for online adjustment of the AP value of the servo valve of a steam turbine regulating valve according to claim 1, characterized in that, In steps S2 and S3, the first adjusting member (4) rotates at an angle not greater than 30° each time, and the second adjusting member (5) rotates at an angle not greater than 30° each time.

3. The method for online adjustment of the AP value of the servo valve of the turbine regulating valve according to claim 2, characterized in that, The sum of the angles at which the first adjusting member (4) rotates multiple times in the same direction is no greater than 360°, and the sum of the angles at which the second adjusting member (5) rotates multiple times in the same direction is no greater than 360°.

4. The method for online adjustment of the AP value of the servo valve of the turbine regulating valve according to claim 2, characterized in that, The first adjusting member (4) and the second adjusting member (5) rotate by the same angle each time.

5. The method for online adjustment of the AP value of the servo valve of a steam turbine regulating valve according to any one of claims 1-4, characterized in that, In step S2, after the valve sleeve (3) abuts against the first adjusting member (4), or in step S3, after the valve sleeve (3) abuts against the second adjusting member (5), the first adjusting member (4) and the second adjusting member (5) are tightened with a tightening torque of 2.5 N·m.

6. The method for online adjustment of the AP value of the servo valve of a steam turbine regulating valve according to any one of claims 1-3, characterized in that, Before step S1, the following is also included: Confirm that the servo valve, its cooperating drive mechanism, and valve body are fault-free; Confirm that the servo valve has no input, including that the drive mechanism is closed, the corresponding GFR system oil pump is stopped and depressurized, and the aviation plug is not connected.

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