Steam turbine regulating valve jam monitoring method and steam turbine regulating valve

Abstract

The invention relates to a steam turbine regulating valve jam monitoring method, the steam turbine regulating valve comprises a valve rod assembly, a valve core and a hydraulic servo-motor execution mechanism, and the method comprises the following steps: obtaining an initial friction force f0 borne by the valve rod assembly in an initial state; according to the initial friction force f0, an early warning threshold value A of the steam turbine regulating valve is determined; a calculation model between the variable load rate of the steam turbine regulating valve and the friction force borne by the valve rod assembly is built; acquiring real-time operation parameters of the steam turbine and inputting the real-time operation parameters into the calculation model so as to calculate real-time friction force f borne by the valve rod assembly; the relation between the real-time friction force f and the early warning threshold value A is judged to generate a judgment result of the jamming degree of the steam turbine regulating valve, and the method has the advantages that the monitoring accuracy is improved, and misjudgment is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of valve operation monitoring in thermal power plants, and in particular to a method for monitoring the sticking of a steam turbine regulating valve and a steam turbine regulating valve. Background Art

[0002] A steam turbine is a turbine machine that uses high-temperature, high-pressure steam as a working medium. When working, the amount of steam entering the turbine needs to be controlled through the high-pressure main steam regulating valve and the medium-pressure combined steam valve and other turbine regulating valves, so as to achieve the start and stop of the turbine and output regulation. As the operation time of the steam turbine increases, the turbine regulating valve may produce oxide scale, valve core deformation and other problems, resulting in the turbine regulating valve becoming stuck, the valve stem structure cannot be raised or lowered normally, affecting the opening and closing of the turbine regulating valve, and further causing the turbine unit to fail to respond to the grid's dispatching requirements to increase or decrease load, and unable to shut down in an emergency, etc., seriously affecting the precise control and safety of the steam turbine unit.

[0003] Therefore, accurate detection of the stuck state of the turbine control valve can timely solve the stuck fault of the turbine control valve, thereby effectively ensuring the safe and stable operation of the turbine, and avoiding unit losses and safety hazards caused by the untimely response of the unit due to the stuck fault of the turbine control valve. For example, a method for monitoring the stuck state of the valve stem of a turbine valve disclosed in the Chinese patent with publication number CN116263111A specifically discloses: when the turbine unit is running, the vibration response characteristic value on the valve stem is monitored, the vibration response characteristic value on the valve stem in the initial state of the turbine unit operation is used as a reference value, the current vibration response characteristic value on the monitored valve stem is compared with the reference value, and the degree of the current valve stem stuck is judged according to the difference between the current vibration response characteristic value and the reference value.

[0004] However, the above scheme determines the degree of valve stem sticking by monitoring valve stem vibration, but does not distinguish the factors affecting the change of valve stem force. Therefore, it is impossible to quantitatively evaluate the degree of valve sticking, resulting in large identification errors, difficulty in distinguishing the cause of the fault, and easy to lead to misjudgment. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a method for monitoring the sticking of a steam turbine regulating valve and a steam turbine regulating valve.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for monitoring a stuck steam turbine regulating valve, wherein the steam turbine regulating valve comprises a valve stem assembly, a valve core and an oil motor actuator, and comprises the following steps:

[0008] Obtaining the initial friction force f0 of the valve stem assembly in the initial state;

[0009] Determining a warning threshold value A of the steam turbine regulating valve according to the initial friction force f0;

[0010] Constructing a calculation model between the variable load rate of the steam turbine regulating valve and the friction force on the valve stem assembly;

[0011] Acquire the real-time operating parameters of the steam turbine and input them into the calculation model to calculate the real-time friction force f on the valve stem assembly;

[0012] The relationship between the real-time friction force f and the warning threshold value A is determined to generate a determination result of the sticking degree of the steam turbine regulating valve.

[0013] Preferably, the construction of a calculation model between the variable load rate of the steam turbine regulating valve and the friction force exerted on the valve stem assembly comprises the following steps:

[0014] Obtaining the driving force F exerted on the valve stem assembly;

[0015] The gravity G on the valve stem assembly is calculated using the following formula:

[0016] G = M × g;

[0017] Where M is the sum of the design mass of the valve stem assembly and the valve core, kg; g is the acceleration due to gravity, m / s 2 ;

[0018] Calculate the steam pressure P of the steam turbine acting on the valve core. The calculation formula is:

[0019] P=(p1-p2)×S m ;

[0020] Where, p1 is the steam pressure at the steam inlet of the steam turbine control valve, Pa; p2 is the steam pressure at the steam outlet of the steam turbine control valve, Pa; S m is the valve core force area, m 2 ;

[0021] Calculate the acceleration force F required to lift the load a , the calculation formula is:

[0022] F a =M×a;

[0023]

[0024] Where, L is the total valve stroke, m; ΔO is the change in valve opening; ΔZT is the change in the comprehensive valve position command, %; △AGC is the load change rate, % / min; M is the sum of the design mass of the valve stem assembly and the valve core, kg; a is the acceleration of the valve stem assembly, m / s 2 .

[0025] Derive the calculation model formula of real-time friction force f,

[0026] When the turbine regulating valve is adjusted to a larger value, the calculation model formula is:

[0027]

[0028] When the turbine regulating valve is adjusted to a smaller value, the calculation model formula is:

[0029]

[0030] Preferably, obtaining the driving force F exerted on the valve stem assembly comprises the following steps:

[0031] A force measuring device is provided on the valve stem assembly to obtain the driving force F.

[0032] Preferably, obtaining the initial friction force f0 of the valve stem assembly in the initial state comprises the following steps:

[0033] After the turbine control valve is installed or repaired, a preset group of friction test data is obtained, and a relative error B of the preset group of friction test data is calculated;

[0034] Determine whether the relative error B is less than 5%. If so, the average value of the preset group of friction test data is the initial friction force f0; if not, repeatedly obtain the preset friction test data and calculate the relative error B of the preset group of friction test data until the initial friction force f0 is obtained.

[0035] Preferably, the warning threshold A includes a first threshold A1 and a second threshold A2; the first threshold A1 is 1.2f0; the second threshold A2 is 1.5f0.

[0036] Preferably, the result of judging the sticking degree of the steam turbine regulating valve includes:

[0037] When the real-time friction force f≥A1, an alarm signal is output;

[0038] When the real-time friction force f≥A2, an emergency signal is output.

[0039] A steam turbine regulating valve applicable to the above-mentioned steam turbine regulating valve jam monitoring method comprises a valve seat, a valve stem assembly, a valve core, an oil motor actuator and a force measuring device;

[0040] The valve stem assembly and the oil motor actuator are mounted on the valve seat;

[0041] One end of the valve stem assembly is fixedly connected to the valve core, and the other end is connected to the hydraulic motor actuator;

[0042] The force measuring device is arranged on the valve stem assembly.

[0043] Preferably, the valve stem assembly comprises a travel pointer for indicating the valve opening.

[0044] Preferably, the valve stem assembly comprises a first stem and a second stem;

[0045] The force measuring device comprises a first connecting member, a second connecting member and a force sensitive element;

[0046] One end of the first connecting rod is connected to the first rod, and the other end is connected to the force sensitive element;

[0047] One end of the second connecting member is connected to the second rod, and the other end is connected to the force sensitive element.

[0048] Preferably, the valve seat comprises a guide sleeve, and the guide sleeve is slidably connected to the valve stem assembly;

[0049] The steam turbine regulating valve further comprises an elastic component, one end of which is fixedly connected to the guide sleeve, and the other end of which is fixedly connected to the tray component;

[0050] A plurality of elastic components are distributed in an array along the circumference of the valve stem assembly, or a central axis of the elastic component coincides with a central axis of the valve stem assembly.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The method for monitoring the stuckness of a steam turbine control valve provided in the above technical solution can obtain the real-time friction force f exerted on the valve stem assembly according to the actual operating parameters of the steam turbine by constructing a calculation model between the friction force exerted on the steam turbine control valve and the valve stem assembly. By only taking the valve stem assembly as the research object, the influence of other structures in the steam turbine control valve (such as elastic components, oil motor failure, etc.) on the calculation result of the real-time friction force f can be eliminated, and the monitoring accuracy can be improved. In this scheme, the real-time friction force f exerted on the valve stem assembly can be calculated in real time, and then the stuckness of the steam turbine control valve can be quantitatively fed back, making the detection result more intuitive and clear, and it is easier to identify the stuckness of the steam turbine control valve and avoid misjudgment. Correspondingly, the steam turbine control valve based on the above-mentioned method for monitoring the stuckness of a steam turbine control valve can realize quantitative monitoring of its stuckness, and the monitoring result is more accurate and can avoid misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic diagram of the steps of one example of the method for monitoring a stuck turbine regulating valve provided by the present invention.

[0055] Figure 2 for Figure 1 A schematic diagram of one example of the S3 step.

[0056] Figure 3 It is the flow management function curve of the regulating valve.

[0057] Figure 4 A schematic structural diagram of one example of a steam turbine regulating valve provided by the present invention.

[0058] Figure 5 for Figure 4 Enlarged schematic diagram of position D in the middle.

[0059] Description of reference numerals:

[0060] 100, steam inlet; 200, steam outlet; 400, oil outlet; 300, oil supply port; 1, valve seat; 11, guide sleeve; 2, valve stem assembly; 20, travel pointer; 21, first rod; 22, second rod; 3, valve core; 4, oil motor actuator; 41, tray; 42, push rod; 43, diaphragm; 5, force measuring device; 51, first connecting piece; 52, second connecting piece; 53, force sensitive element; 6, elastic component. DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] See also Figures 1 to 3 The embodiment of the present invention provides a method for monitoring a stuck steam turbine regulating valve, comprising the following steps:

[0065] S1: Obtain the initial friction force f0 of the valve stem assembly in the initial state;

[0066] S2: Determine the warning threshold value A of the steam turbine regulating valve according to the initial friction force f0;

[0067] S3: Construct a calculation model between the variable load rate of the steam turbine control valve and the friction force on the valve stem assembly;

[0068] S4: obtaining real-time operating parameters of the steam turbine and inputting them into a calculation model to calculate the real-time friction force f on the valve stem assembly;

[0069] S5: Determine the relationship between the real-time friction force f and the warning threshold value A to generate a determination result of the sticking degree of the steam turbine regulating valve.

[0070] By constructing a calculation model between the friction force exerted on the turbine control valve and the valve stem assembly, the real-time friction force f exerted on the valve stem assembly can be obtained according to the actual operating parameters of the turbine. By only taking the valve stem assembly as the research object, the influence of other structures in the turbine control valve (such as elastic components, oil motor failure, etc.) on the calculation result of the real-time friction force f can be eliminated, which can improve the monitoring accuracy. In this scheme, the real-time friction force f exerted on the valve stem assembly can be calculated in real time, and then the sticking degree of the turbine control valve can be quantitatively fed back, making the detection result more intuitive and clear.

[0071] Furthermore, the above S3 step specifically includes:

[0072] S3.1: Obtain the driving force F acting on the valve stem assembly.

[0073] S3.2: Calculate the gravity force G acting on the valve stem assembly.

[0074] Specifically, the calculation formula for gravity G is:

[0075] G=M×g; (1)

[0076] Where M is the sum of the design mass of the valve stem assembly and the valve core, kg; g is the acceleration due to gravity, m / s 2 It can be known that M is the design parameter of the steam turbine regulating valve. After obtaining the corresponding steam turbine regulating valve, M is known. g is taken as 9.8m / s 2 .

[0077] S3.3: Calculate the steam pressure P of the turbine steam acting on the valve core.

[0078] Specifically, the steam pressure P is calculated as:

[0079] P=(p1-p2)×S m ; (2)

[0080] Where, p1 is the steam pressure at the steam inlet of the steam turbine control valve, Pa; p2 is the steam pressure at the steam outlet of the steam turbine control valve, Pa; S m is the valve core force area, m 2 . It is known that S m is the projection area of ​​the valve core along the axial direction of the valve stem assembly, which is also the design parameter of the steam turbine control valve. After obtaining the corresponding steam turbine control valve, S m is known. p2 and p1 can be obtained from the DCS system. It should be noted that since the valve stem of the steam turbine regulating valve is usually a vertical structure, the projected area of ​​the top and bottom of the valve core is equal, both S m , that is, formula (2) is a simplified formula. In other embodiments, if the areas are not equal, the pressure difference can also be calculated based on the actual corresponding areas.

[0081] S3.4: Calculate the acceleration force F required to lift and lower the load a , the calculation formula is:

[0082] F a =M×a; (3-1)

[0083]

[0084] Where, L is the total valve travel, m; ΔO is the change in valve opening, %; ΔZT is the change in the comprehensive valve position command; △AGC is the load change rate, % / min. M is the sum of the design mass of the valve stem assembly and the valve core, kg; a is the acceleration of the valve stem assembly, m / s 2 .

[0085] Specifically, the acceleration a of the valve stem assembly can be obtained after the dispatching instruction given by the system. Figure 3 Taking a certain type of steam turbine regulating valve as an example, when the unit receives a comprehensive valve position instruction to adjust from 60% to 80%, and the load change rate is 2% / min, the opening of the high-pressure regulating valve GV3 needs to be increased from 9% to 81%. Through the comprehensive valve position instruction and the load change rate, it can be calculated that the regulating valve needs to be adjusted within 10 minutes. According to the manual of this regulating valve, the total stroke L of the high-pressure regulating valve GV3 is 55.8mm. The corresponding acceleration can be further calculated based on the above formula (3-2).

[0086] It should be noted that if Figure 3 As shown, the regulating valves GV1 and GV2 of the steam turbine unit are usually opened diagonally synchronously, so the flow management curves of the four valves of the unit are 3. That is: the first one on the left is GV1 and GV2, the middle one is GV3, and the right one is GV4.

[0087] Similarly, when the unit receives a dispatch instruction and the comprehensive valve position instruction needs to be adjusted from 80% to 60%, and the load change rate is 1% / min, Figure 3 It can be seen that the opening of the high-pressure regulating valve GV3 needs to be reduced from 81% to 9%. By combining the valve position command and the load change rate, it can be calculated that the regulating valve needs to be adjusted within 20 minutes. The corresponding acceleration can be further calculated according to the above formula (3-2).

[0088] S3.5: Derive the calculation model formula of the real-time friction force f.

[0089] Specifically, through the force analysis (force balance) of the valve stem assembly, it can be known that when the turbine control valve is adjusted down, the force meets the following requirements:

[0090] F a =F+G+Pf (4-1)

[0091] Combining the above formulas (1), (2), (3-1), (3-2) and (4-1), it can be deduced that when the turbine control valve is adjusted to a small value, the calculation model formula is:

[0092]

[0093] Similarly, through the force analysis (force balance) of the valve stem assembly, it can be known that when the turbine control valve is adjusted larger, the force meets the following requirements:

[0094] F a =F-(P+G+f) (4-2)

[0095] Combining the above formula (1), formula (2), formula (3-1), formula (3-2) and formula (4-2), it can be deduced that when the turbine control valve is adjusted to a larger value, the calculation model formula is:

[0096]

[0097] Furthermore, in this embodiment, S3.1 may specifically be to provide a force measuring device on the valve stem assembly to obtain the driving force F.

[0098] Since the turbine regulating valves that are newly installed or retested after maintenance need to undergo valve performance tests before being put into use, they can only be put into use after ensuring that all performance indicators are qualified.

[0099] In order to improve the accuracy of the initial friction force f0 obtained, and at the same time, improve the monitoring accuracy of the steam turbine regulating valve after it is put into use, in this embodiment, step S1 specifically includes the following steps:

[0100] After the turbine control valve is installed or repaired, a preset group of friction force test data is obtained, and a relative error B of the preset group of friction force test data is calculated;

[0101] Determine whether the relative error B is less than 5%. If so, the average value of the preset group of friction test data is the initial friction force f0; if not, repeatedly obtain the preset friction test data and calculate the relative error B of the preset group of friction test data until the initial friction force f0 is obtained.

[0102] The warning threshold A can be set according to factors such as the actual unit capacity and the setting position of the turbine control valve. In this embodiment, the warning threshold A includes a first threshold A1 and a second threshold A2; the first threshold A1 is 1.2f0; the second threshold A2 is 1.5f0.

[0103] Furthermore, the result of judging the degree of the stuckness of the steam turbine regulating valve includes outputting an alarm signal when the real-time friction force f≥A1, and outputting an emergency signal when the real-time friction force f≥A2. Of course, in other embodiments, a third threshold value, a fourth threshold value, etc. can also be set to match different stuck states of the steam turbine regulating valve.

[0104] See also Figure 4 and Figure 5This embodiment also provides a steam turbine regulating valve based on the above-mentioned steam turbine regulating valve jam monitoring method, including a valve seat 1, a valve stem assembly 2, a valve core 3, an oil motor actuator 4, a force measuring device 5 and an elastic assembly 6.

[0105] Specifically, the valve stem assembly 2 and the oil motor actuator 4 are installed on the valve seat 1, one end of the valve stem assembly 2 is fixedly connected to the valve core 3, and the other end is connected to the oil motor actuator 4. Under the action of the oil motor actuator 4 and the elastic assembly 6, the valve stem assembly 2 can slide along the guide sleeve 11, that is, slide along the X1 direction and the X2 direction in the figure; thereby changing the steam flow of the turbine.

[0106] Specifically, the force measuring device 5 is arranged on the valve stem assembly 2, and the force measuring device 5 can be used to directly measure the driving force F applied to the valve stem assembly 2 by the oil motor actuator 4. Further, taking the valve stem assembly 2 as the analysis object, a calculation model between the variable load rate of the turbine control valve and the friction force exerted on the valve stem assembly 2 can be constructed. On the one hand, the friction force exerted on the valve stem assembly 2 can be quantified, and the monitoring is accurate, which is convenient for intuitively and clearly monitoring the sticking degree of the turbine control valve; on the other hand, the influence of the failure of the oil motor actuator 4 or the elastic component 6 itself on the friction force exerted on the valve stem assembly 2 is eliminated (it can be known that this friction force can directly represent the sticking degree of the turbine control valve), so that less data needs to be monitored, thereby improving the monitoring accuracy of the sticking degree of the turbine control valve.

[0107] Furthermore, the valve stem assembly 2 includes a travel pointer 20 for indicating the valve opening.

[0108] See also Figure 4 The valve seat 1 includes a guide sleeve 11, which is slidably connected to the valve stem assembly 2; the elastic component 6 is set as a spring, one end of the elastic component 6 is fixedly connected to the guide sleeve 11, and the other end is fixedly connected to the oil motor actuator 4. A plurality of elastic components 6 are distributed in an array along the circumference of the valve stem assembly 2, or the central axis of the elastic component 6 coincides with the central axis of the valve stem assembly 2, so that the force of the valve stem assembly 2 is balanced, and the valve stem assembly 2 is prevented from being subjected to a force deviating from the central axis direction thereof, which affects the sliding of the valve stem assembly 2 along the guide sleeve 11.

[0109] See also Figure 4The oil motor actuator 4 includes a tray 41, a push rod 42 and a diaphragm 43. When the oil is supplied to the turbine control valve, the diaphragm 43, the push rod 42, the diaphragm 43 and the valve stem assembly 2 are driven to slide synchronously, and the valve core 3 is further driven to slide along the guide sleeve 11, that is, slide along the X1 direction and the X2 direction in the figure, thereby changing the steam flow of the turbine. It can be known that when the turbine control valve is supplied with oil, the oil is input from the oil supply port 300 of the turbine control valve and output from the oil outlet 400 of the turbine control valve. The oil pressure can be adjusted by adjusting the oil, thereby realizing the sliding control of the diaphragm 43, the push rod 42, the tray 41 and the valve stem assembly 2.

[0110] See also Figure 4 The valve seat 1 is provided with a steam inlet 100 and a steam outlet 200, the steam inlet 100 and the steam outlet 200 are connected through the valve port, and the valve core 3 is arranged for the valve port. When the valve core 3 moves along the X1 direction, the valve opening of the steam turbine regulating valve increases, and the steam flow through the steam inlet 100, the valve port, and the steam outlet 200 increases. Correspondingly, when the valve core 3 moves along the X2 direction, the valve opening of the steam turbine regulating valve decreases, and the steam flow through the steam inlet 100, the valve port, and the steam outlet 200 decreases.

[0111] See also Figure 5 There are many ways to set the force measuring device 5 and the valve stem assembly 2, as long as the driving force F applied to the valve stem can be measured. In this embodiment, the valve stem assembly 2 includes a first rod 21 and a second rod 22; the force measuring device 5 includes a first connecting member 51, a second connecting member 52 and a force sensitive element 53; one end of the first connecting rod is connected to the first rod 21, and the other end is connected to the force sensitive element 53; one end of the second connecting member 52 is connected to the second rod 22, and the other end is connected to the force sensitive element 53, wherein the first connecting member 51 and the second connecting member 52 are both configured as bolts. Of course, in other embodiments, the force measuring device 5 can also be pasted at the corresponding position of the valve stem assembly 2 using a strain gauge, and can also be cast integrally with the valve stem assembly 2.

[0112] It is worth noting that, in this embodiment, the valve stem assembly 2 includes a first rod 21 and a second rod 22, and M is the sum of the design masses of the valve stem assembly and the valve core, that is, M includes the masses of the first rod 21 and the second rod 22. For accurate calculation, in actual calculation, the mass corresponding to the second rod 22 can be subtracted from M, or in the actual process of manufacturing the steam turbine regulating valve, the mass of the second rod 22 can be reduced so that the mass of the second rod 22 can be ignored relative to M.

[0113] Furthermore, the force measuring device 5 can achieve accurate force measurement by converting the force acting thereon into an electrical signal for output based on the principle of elastic deformation. Specifically, when the object to be measured (valve stem assembly 2) is subjected to an external force, the elastic element inside the force measuring device 5 will produce strain, thereby generating an electrical signal, which is proportional to the magnitude of the force. By processing and converting the signal, accurate force measurement can be achieved.

[0114] Based on the above-mentioned steam turbine regulating valve, it can be known that when the dispatcher issues an increase load instruction, it is necessary to increase the steam flow rate entering the steam turbine by controlling the steam turbine regulating valve to open wider. At this time, the oil outlet 400 is closed, the oil supply port 300 is opened, and the oil pressure is increased. Under the action of the oil pressure, the diaphragm 43 is pushed upward, and the diaphragm 43 pushes the tray 41 upward through the push rod 42, thereby overcoming the elastic force of the spring component to push the valve core 3 to increase the opening relative to the valve seat 1, and quantitatively increase the amount of steam entering the steam turbine under the indication of the stroke pointer 20. When the dispatcher issues a load reduction instruction, it is necessary to reduce the amount of steam entering the steam turbine by controlling the steam turbine regulating valve to close smaller. At this time, the oil outlet 400 is opened, the oil supply port 300 is closed, and the oil pressure is reduced, so that under the action of the elastic force of the spring component, the valve core 3 is pushed to reduce the opening relative to the valve seat 1, and quantitatively reduce the amount of steam entering the steam turbine under the indication of the stroke pointer 20.

[0115] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for monitoring the jamming of a steam turbine regulating valve, wherein the steam turbine regulating valve comprises a valve stem assembly, a valve core and an oil motor actuator, characterized in that: The following steps are involved: Obtaining the initial friction force f0 of the valve stem assembly in the initial state; Determining a warning threshold value A of the steam turbine regulating valve according to the initial friction force f0; Constructing a calculation model between the variable load rate of the steam turbine regulating valve and the friction force on the valve stem assembly; Acquire the real-time operating parameters of the steam turbine and input them into the calculation model to calculate the real-time friction force f on the valve stem assembly; The relationship between the real-time friction force f and the warning threshold value A is determined to generate a determination result of the sticking degree of the steam turbine regulating valve.

2. A method for monitoring a steam turbine regulating valve jam according to claim 1, characterized in that: The step of constructing a calculation model between the variable load rate of the steam turbine regulating valve and the friction force on the valve stem assembly specifically comprises the following steps: Obtaining the driving force F exerted on the valve stem assembly; The gravity G on the valve stem assembly is calculated using the following formula: G = M × g; Where M is the sum of the design mass of the valve stem assembly and the valve core, kg; g is the acceleration due to gravity, m / s 2 ; Calculate the steam pressure P of the steam turbine acting on the valve core. The calculation formula is: P=(p1-p2)×S m ; Where, p1 is the steam pressure at the steam inlet of the steam turbine control valve, Pa; p2 is the steam pressure at the steam outlet of the steam turbine control valve, Pa; S m is the valve core force area, m 2 ; Calculate the acceleration force F required to lift the load a , the calculation formula is: F a =M×a; Where, L is the total valve stroke, m; ΔO is the change in valve opening; ΔZT is the change in the comprehensive valve position command, %; △AGC is the load change rate, % / min; M is the sum of the design mass of the valve stem assembly and the valve core, kg; a is the acceleration of the valve stem assembly, m / s 2 ; Derive the calculation model formula of real-time friction force f, When the turbine regulating valve is adjusted to a larger value, the calculation model formula is: When the turbine regulating valve is adjusted to a smaller value, the calculation model formula is:

3. A method for monitoring a steam turbine regulating valve jam according to claim 2, characterized in that: Obtaining the driving force F of the valve stem assembly; specifically comprising the following steps: A force measuring device is provided on the valve stem assembly to obtain the driving force F.

4. A method for monitoring a steam turbine regulating valve jam according to claim 1, characterized in that: Obtaining the initial friction force f0 of the valve stem assembly in the initial state comprises the following steps: After the turbine control valve is installed or repaired, a preset group of friction test data is obtained, and a relative error B of the preset group of friction test data is calculated; Determine whether the relative error B is less than 5%. If so, the average value of the preset group of friction test data is the initial friction force f0; if not, repeatedly obtain the preset friction test data and calculate the relative error B of the preset group of friction test data until the initial friction force f0 is obtained.

5. A method for monitoring a steam turbine regulating valve jam according to claim 1, characterized in that: The warning threshold A includes a first threshold A1 and a second threshold A2; the first threshold A1 is 1.2f0; the second threshold A2 is 1.5f0.

6. A method for monitoring a steam turbine regulating valve jam according to claim 5, characterized in that: The result of judging the sticking degree of the steam turbine regulating valve includes: When the real-time friction force f≥A1, an alarm signal is output; When the real-time friction force f≥A2, an emergency signal is output.

7. A steam turbine regulating valve applicable to the method for monitoring the sticking of a steam turbine regulating valve as claimed in any one of claims 1 to 6, characterized in that: It includes valve seat, valve stem assembly, valve core, oil motor actuator and force measuring device; The valve stem assembly and the oil motor actuator are mounted on the valve seat; One end of the valve stem assembly is fixedly connected to the valve core, and the other end is connected to the hydraulic motor actuator; The force measuring device is arranged on the valve stem assembly.

8. The steam turbine regulating valve according to claim 7, characterized in that: The valve stem assembly includes a travel pointer for indicating the valve opening.

9. The steam turbine regulating valve according to claim 7, characterized in that: The valve stem assembly includes a first rod and a second rod; The force measuring device comprises a first connecting member, a second connecting member and a force sensitive element; One end of the first connecting rod is connected to the first rod, and the other end is connected to the force sensitive element; One end of the second connecting member is connected to the second rod, and the other end is connected to the force sensitive element.

10. The steam turbine regulating valve according to claim 7, characterized in that: The valve seat comprises a guide sleeve, and the guide sleeve is slidably connected to the valve stem assembly; The steam turbine regulating valve further comprises an elastic component, one end of which is fixedly connected to the guide sleeve, and the other end of which is fixedly connected to the tray component; A plurality of elastic components are distributed in an array along the circumference of the valve stem assembly, or a central axis of the elastic component coincides with a central axis of the valve stem assembly.

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