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

Abstract

The invention relates to a steam turbine regulating valve performance monitoring method and a steam turbine regulating valve. The method comprises the following steps: dividing working conditions; constructing a calculation model of the operation performance indexes of the regulating valve under different working conditions; initial measurement values of the operation performance indexes of the regulating valve under different working conditions are obtained, and a health index database is established; constructing an early warning threshold database of the operation performance indexes under different working conditions according to the health index database; the real-time value of the running time of the valve rod assembly under the preset stroke is obtained; judging whether the real-time value of the operation time exceeds an early warning threshold value of a working condition corresponding to the operation time or not; if yes, according to a calculation model, the real-time value of friction force between the valve rod assembly and the valve seat, the real-time value of thrust borne by an actuating mechanism of the hydraulic servo-motor and the real-time value of the elastic stiffness coefficient of the spring assembly are calculated so as to diagnose the fault position of the adjusting valve; the method has the advantages that the performance of the regulating valve can be accurately monitored, and the fault position can be quickly judged.

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 performance 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 the working medium. When working, it is necessary to control the amount of steam entering the turbine through turbine regulating valves such as the high-pressure main steam regulating valve and the medium-pressure combined steam valve, so as to achieve the start and stop of the steam turbine and output regulation.

[0003] As the operation time of the steam turbine increases, the turbine control valve may produce oxide scale, valve core deformation, spring aging, oil motor instability and other problems, which may lead to control valve operation failure, affect the opening and closing of the steam turbine control valve, and further cause the steam turbine unit to fail to respond to the grid's dispatching requirements to increase or decrease load, and fail to shut down in an emergency, which seriously affects the precise control and safety of the steam turbine unit. Due to the many types of steam turbine failures, there is no good solution in the existing technical means to accurately monitor the performance of the steam turbine control valve and quickly determine the fault location.

[0004] Therefore, it is urgent for those skilled in the art to provide a method for monitoring the performance of a steam turbine control valve and a steam turbine control valve so as to accurately monitor the performance of the steam turbine control valve and quickly determine the fault location. 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 performance 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 the performance of a steam turbine regulating valve, wherein the regulating valve comprises a valve seat, a valve stem assembly, a valve core, an oil motor actuator and a spring assembly, wherein the oil motor actuator comprises a tray, and the tray is connected to the valve stem assembly; one end of the spring assembly is connected to the tray, and the other end is connected to the valve seat;

[0008] The following steps are involved:

[0009] Divide the working conditions based on the historical operating data or design data of the control valve;

[0010] Constructing a calculation model for the operating performance index of the regulating valve under different working conditions, wherein the operating performance index includes the operating time of the valve stem assembly under a preset stroke, the friction between the valve stem assembly and the valve seat, the thrust of the hydraulic motor actuator, and the elastic stiffness coefficient of the spring assembly;

[0011] Obtaining initial measurement values ​​of the operating performance indicators of the control valve under different working conditions and establishing a health indicator database;

[0012] Building a warning threshold database of the operating performance indicators under different working conditions according to the health indicator database;

[0013] Obtaining a real-time value of the running time of the valve stem assembly under a preset stroke;

[0014] Determine whether the real-time value of the operating time exceeds the warning threshold of the operating condition corresponding to the operating time; if so, calculate the real-time value of the friction between the valve stem assembly and the valve seat, the real-time value of the thrust exerted on the oil motor actuator, and the real-time value of the elastic stiffness coefficient of the spring assembly according to the calculation model to diagnose the fault location of the regulating valve.

[0015] Preferably, the hydraulic motor actuator further comprises a connecting rod and a diaphragm; the tray is fixedly connected to the diaphragm through the connecting rod; the diaphragm is driven to slide by the hydraulic motor;

[0016] The construction of the calculation model of the operating performance index of the regulating valve under different working conditions includes constructing a calculation model between the variable load rate of the regulating valve and the elastic stiffness coefficient under different working conditions; specifically includes the following steps:

[0017] Obtain a first force F applied by the valve stem assembly to the tray 12 ;

[0018] The gravity G1 on the tray is calculated using the following formula:

[0019] G1 = M1 × g;

[0020] Where M1 is the design mass of the pallet, kg; g is the acceleration due to gravity, m / s 2 ;

[0021] The thrust T applied by the hydraulic motor to the diaphragm is calculated using the following formula:

[0022] T=P y ×S1;

[0023] P y is the oil supply pressure of the oil motor, Pa; S1 is the design area of ​​the diaphragm, m 2 ;

[0024] Calculate the acceleration force F required to lift the load a1 , the calculation formula is:

[0025] F a1 =M1×a;

[0026]

[0027] Wherein, t is the preset time, s; a is the acceleration of the valve stem assembly, m / s 2 ; △h is the stroke of the valve stem assembly in time t, m;

[0028] Calculate the elastic force F applied by the spring assembly to the tray k , the calculation formula is:

[0029] F k = k × ΔH;

[0030] Where ΔH is the deformation of the spring assembly, m;

[0031] The calculation model for deriving the elastic stiffness coefficient of the spring assembly is:

[0032] When the regulating valve is in a closed state, the spring assembly is in a free state. When the turbine regulating valve is adjusted to a larger value, the calculation model formula of the elastic stiffness coefficient k is:

[0033]

[0034] When the turbine regulating valve is adjusted to a small value, the calculation model formula of the elastic stiffness coefficient k is:

[0035]

[0036] Preferably, the first force F applied by the valve stem assembly to the tray is obtained. 12 ; Specifically including the following steps:

[0037] A force measuring device is provided on the valve stem assembly to detect the first force F 12 .

[0038] Preferably, the acceleration force F required for calculating the load lifting rate is a1 ,include:

[0039] A displacement measuring device is installed on the tray to measure the preset time t and the stroke of the valve stem assembly within the time t.

[0040] Preferably, the construction of the calculation model of the operating performance index of the regulating valve under different working conditions also includes constructing a calculation model between the variable load rate of the regulating valve and the friction force under different working conditions; specifically including the following steps:

[0041] Obtain a second force F applied by the tray to the valve stem assembly 21 ;

[0042] The gravity G2 on the valve stem assembly is calculated using the following formula:

[0043] G2 = M2 × g;

[0044] Where M2 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 ;

[0045] The steam pressure P of the steam turbine acting on the valve core is calculated using the following formula:

[0046] P = (p1-p2) × S2;

[0047] 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; S2 is the valve core force area, m 2 ;

[0048] Calculate the acceleration force F required to lift the load a2 , the calculation formula is:

[0049] F a2 =M2×a;

[0050]

[0051] Wherein, t is the preset time, s; △h is the stroke of the valve stem assembly within t time, m; a is the acceleration of the valve stem assembly, m / s 2 ;

[0052] Derive the calculation model formula of friction force f,

[0053] When the turbine regulating valve is adjusted to a larger value, the calculation model formula of the friction force f is:

[0054]

[0055] When the turbine regulating valve is adjusted to a small value, the calculation model formula of the friction force f is:

[0056]

[0057] Preferably, the operating condition division based on the historical operating data or design data of the regulating valve comprises the following steps:

[0058] Based on the historical operation data or design data of the control valve, obtain the change range of the inlet and outlet pressure difference of the control valve;

[0059] According to the preset pressure difference interval, the pressure difference variation range is divided into several groups to represent different working conditions.

[0060] Preferably, the method of obtaining the initial measurement values ​​of the operating performance indicators of the regulating valve under different working conditions and establishing a health indicator database specifically includes the following steps:

[0061] After the steam turbine control valve is installed or repaired, a performance test is performed on the control valve under different operating conditions to obtain initial measurement values ​​of the operating performance indicators.

[0062] Preferably, the step of constructing a warning threshold database of the operating performance indicators under different working conditions according to the health indicator database specifically includes the following steps:

[0063] Calculating a warning threshold of the operating performance indicator under different operating conditions, wherein the warning threshold has a preset proportional relationship with the initial measurement value;

[0064] All the early warning thresholds are aggregated to form the early warning threshold database.

[0065] A steam turbine regulating valve applicable to the above-mentioned steam turbine regulating valve performance monitoring method is characterized by comprising:

[0066] Valve seat, including valve port and guide sleeve;

[0067] A valve stem assembly is slidably mounted relative to the guide sleeve;

[0068] A valve core is fixedly mounted at one end of the valve stem assembly and slides synchronously with the valve stem assembly to control the opening of the valve port;

[0069] The hydraulic actuator comprises a tray, wherein the tray is connected to an end of the valve stem assembly away from the valve core to drive the valve stem assembly to slide;

[0070] A spring assembly, one end of which is connected to the guide sleeve and the other end of which is connected to the tray;

[0071] A force measuring device, used to measure the force between the tray and the valve stem assembly;

[0072] The displacement measuring device comprises a transmission rod and a displacement sensor, wherein one end of the transmission rod is fixedly connected to the tray, and the other end is connected to the displacement sensor, and the displacement sensor is used to measure the displacement of the transmission rod as the tray slides and the time when the displacement occurs.

[0073] Preferably, the force measuring device comprises a first connecting member, a second connecting member and a force sensitive element;

[0074] One end of the first connecting member is connected to the valve stem assembly, and the other end is connected to the force sensitive element;

[0075] One end of the second connecting member is connected to the tray, and the other end is connected to the force sensitive element.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The above technical solution provides a method for monitoring the performance of a steam turbine control valve. Through this solution, a calculation model for the operating performance indicators of the control valve under different operating conditions is constructed, and the operating performance indicators include the operating time of the valve stem assembly under a preset stroke, the friction between the valve stem assembly and the valve seat, the thrust exerted on the oil motor actuator, and the elastic stiffness coefficient of the spring assembly. On the one hand, it is beneficial to calculate the initial measurement value of the operating performance indicators of the control valve under different operating conditions when the control valve is initially operated, which is convenient for establishing a health indicator database, and further for constructing a warning threshold database of the operating performance indicators under different operating conditions; on the other hand, it is convenient to calculate the real-time value of the operating performance indicators, and then facilitate intuitive and accurate monitoring of the control valve performance. In addition, this solution obtains the real-time value of the running time of the valve stem assembly under the preset stroke, and determines whether the real-time value of the running time exceeds the warning threshold of the working condition corresponding to the running time. When the real-time value of the running time exceeds the warning threshold of the running time, the real-time value of the friction between the valve stem assembly and the valve seat, the real-time value of the thrust received by the oil motor actuator, and the real-time value of the elastic stiffness coefficient of the spring assembly are calculated according to the calculation model to diagnose the fault location. On the one hand, when there is a fault, the fault location can be quickly diagnosed; on the other hand, when it is judged that the real-time value of the running time does not exceed the warning threshold of the working condition corresponding to the running time, it means that the control valve has no fault, and then the calculation of the real-time value of the friction between the valve stem assembly and the valve seat, the real-time value of the thrust received by the oil motor actuator, and the real-time value of the elastic stiffness coefficient of the spring assembly can be omitted, saving the calculation process. Correspondingly, the steam turbine control valve applicable to a steam turbine control valve performance monitoring method provided in the above technical solution has the advantages of being able to accurately monitor the performance of the control valve and quickly determine the fault location. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] 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.

[0079] Figure 1 A schematic diagram of the steps of the method for monitoring the performance of a steam turbine regulating valve provided by the present invention.

[0080] Figure 2 This is a schematic diagram of the force analysis of the tray when the opening of the regulating valve is increased.

[0081] Figure 3This is a schematic diagram of the force analysis of the tray when the regulating valve opening is adjusted to a smaller value.

[0082] Figure 4 This is a schematic diagram of the force analysis of the valve stem assembly when the valve opening of the regulating valve is increased.

[0083] Figure 5 This is a schematic diagram of the force analysis of the valve stem assembly when the valve opening is adjusted to a smaller value.

[0084] Figure 6 A schematic structural diagram of one example of a steam turbine regulating valve provided by the present invention.

[0085] Figure 7 for Figure 6 A magnified schematic diagram of position A in the middle.

[0086] Description of reference numerals:

[0087] 101. Steam inlet; 102. Steam outlet; 103. Oil supply port; 104. Oil outlet; 1. Valve seat; 10. Valve port; 11. Guide sleeve; 2. Valve stem assembly; 20. Travel pointer; 3. Valve core; 4. Oil motor actuator; 41. Tray; 42. Connecting rod; 43. Diaphragm; 5. Spring assembly; 51. Spring; 6. Force measuring device; 61. First connecting piece; 62. Second connecting piece; 63. Force sensitive element; 7. Displacement measuring device; 71. Transmission rod; 72. Displacement sensor. DETAILED DESCRIPTION

[0088] 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.

[0089] 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.

[0090] 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.

[0091] See also Figures 1 to 7 The embodiment of the present invention provides a method for monitoring the performance of a steam turbine control valve. The control valve includes a valve seat 1, a valve stem assembly 2, a valve core 3, an oil motor actuator 4 and a spring assembly 5. The oil motor actuator 4 includes a tray 41, and the tray 41 is connected to the valve stem assembly 2; one end of the spring assembly 5 is connected to the tray 41, and the other end is connected to the valve seat 1.

[0092] In this embodiment, the method for monitoring the performance of a steam turbine regulating valve specifically includes the following steps:

[0093] S1: Divide the operating conditions based on the historical operating data or design data of the control valve.

[0094] S2: Construct a calculation model for the operating performance index of the regulating valve under different working conditions. The operating performance index includes the operating time of the valve stem assembly 2 under the preset stroke, the friction between the valve stem assembly 2 and the valve seat 1, the thrust of the oil motor actuator 4 and the elastic stiffness coefficient of the spring assembly 5.

[0095] S3: Obtain initial measurement values ​​of the operating performance indicators of the control valve under different working conditions and establish a health indicator database.

[0096] S4: Construct a warning threshold database of operating performance indicators under different working conditions based on the health indicator database.

[0097] S5: Obtain the real-time value of the running time of the valve stem assembly 2 under the preset stroke.

[0098] S6: Determine whether the real-time value of the running time exceeds the warning threshold of the working condition corresponding to the running time; if so, calculate the real-time value of the friction between the valve stem assembly 2 and the valve seat 1, the real-time value of the thrust exerted on the oil motor actuator 4 and the real-time value of the elastic stiffness coefficient of the spring assembly 5 according to the calculation model to diagnose the fault location; if not, end the judgment.

[0099] Through this scheme, a calculation model for the operating performance indicators of the control valve under different working conditions is constructed, and the operating performance indicators include the operating time of the valve stem assembly 2 under the preset stroke, the friction between the valve stem assembly 2 and the valve seat 1, the thrust exerted on the oil motor actuator 4 and the elastic stiffness coefficient of the spring assembly 5. On the one hand, it is beneficial to calculate the initial measurement values ​​of the operating performance indicators of the control valve under different working conditions when the control valve is initially operated, which is convenient for establishing a health indicator database, and further for constructing a warning threshold database of the operating performance indicators under different working conditions; on the other hand, it is convenient to calculate the real-time values ​​of the operating performance indicators, and then facilitate intuitive and accurate monitoring of the performance of the control valve. In addition, this solution obtains the real-time value of the running time of the valve stem assembly 2 under the preset stroke, and determines whether the real-time value of the running time exceeds the warning threshold of the working condition corresponding to the running time. When the real-time value of the running time exceeds the warning threshold of the working condition corresponding to the running time, the real-time value of the friction between the valve stem assembly 2 and the valve seat 1, the real-time value of the thrust received by the oil motor actuator 4, and the real-time value of the elastic stiffness coefficient of the spring assembly 5 are calculated according to the calculation model to diagnose the fault location. On the one hand, when there is a fault, the fault location can be quickly diagnosed; on the other hand, when it is determined that the real-time value of the running time does not exceed the warning threshold of the working condition corresponding to the running time, it indicates that the regulating valve is fault-free, and then the calculation of the real-time value of the friction between the valve stem assembly 2 and the valve seat 1, the real-time value of the thrust received by the oil motor actuator 4, and the real-time value of the elastic stiffness coefficient of the spring assembly 5 can be omitted, saving the calculation process.

[0100] In this embodiment, step S1 specifically includes: obtaining the inlet and outlet pressure difference variation range of the regulating valve based on the historical operation data or design data of the regulating valve; dividing the pressure difference variation range into several groups according to the preset pressure difference interval to represent different working conditions.

[0101] Specifically, taking a specific regulating valve as an example, it can be known through the historical operation data or design data of the regulating valve that the pressure difference of the regulating valve varies between 0.2 and 0.5 MPa. When the preset pressure difference interval is set to 0.1 MPa as an incremental parameter as the basis for dividing the working conditions, three groups of working conditions can be divided at this time, as shown in Table 1 below:

[0102] Table 1

[0103] Regulating valve pressure difference range 0.2~0.5MPa First working condition <![CDATA[0.2±σ1MPa~0.3±σ1MPa]]> Second working condition <![CDATA[0.3±σ1MPa~0.4±σ1MPa]]> The third working condition <![CDATA[0.4±σ1MPa~0.5±σ1MPa]]>

[0104] It is worth noting that σ1 is a deviation value set to take into account the actual operating limit of the control valve. σ1 can be set according to actual needs, such as 0.02MPa, 0.05MPa, etc.

[0105] In this embodiment, the hydraulic actuator 4 further includes a connecting rod 42, a diaphragm 43 and a hydraulic actuator 44; the tray 41 is fixedly connected to the diaphragm 43 through the connecting rod 42; and the hydraulic actuator 44 drives the diaphragm 43 to slide. Step S2 includes constructing a calculation model between the variable load rate and the elastic stiffness coefficient of the regulating valve under different working conditions, specifically including the following steps:

[0106] Obtain the first force F applied by the valve stem assembly 2 to the tray 41 12 Specifically, a force measuring device 6 is provided on the valve stem assembly 2, and the force measuring device 6 is connected between the valve stem assembly 2 and the tray 41, so as to detect the first force F 12 .

[0107] The gravity G1 acting on the tray 41 is calculated using the following formula:

[0108] G1=M1×g; Formula (1)

[0109] Wherein, M1 is the design mass of the tray 41, kg; g is the acceleration due to gravity, m / s 2 .

[0110] The thrust T applied by the hydraulic motor to the diaphragm 43 is calculated using the following formula:

[0111] T=P y ×S1; Formula (2)

[0112] Where P y is the oil supply pressure of the oil motor 44, Pa; S1 is the design area of ​​the diaphragm 43, m 2 .

[0113] Calculate the acceleration force F required to lift the load a1 , the calculation formula is:

[0114] F a1 =M1×a; Formula (3)

[0115]

[0116] Where t is the preset time, s; △h is the stroke of the valve stem assembly 2 within the time t, m; a is the acceleration of the valve stem assembly 2, m / s 2 It can be known that the displacement measuring device 7 is installed on the tray 41 to measure the preset time t and the stroke Δh of the valve stem assembly 2 within the time t.

[0117] Calculate the elastic force F applied by the spring assembly to the tray k , the calculation formula is:

[0118] F k = k × ΔH;

[0119] Wherein, ΔH is the deformation of the spring assembly, m. It can be known that ΔH and △h are interrelated, and ΔH can be obtained by knowing △h. Since the spring assembly 5 is in a free state in the initial state when the regulating valve is closed, ΔH = Δh during the process of increasing the valve opening of the regulating valve; when the valve opening of the regulating valve is reduced, ΔH = H-Δh, and H is the compression of the spring when the valve opening of the regulating valve is at the final position of the increased valve opening.

[0120] The calculation model of the elastic stiffness coefficient of the spring assembly 5 is derived. The force analysis is carried out with the tray 41 as the research object, as follows:

[0121] See also Figure 2 and Figure 6 When the regulating valve opening is increased, the force balance of the tray 41 shows that:

[0122] F a1 =TF 12 -F k -G1; Formula (5)

[0123] F k =k×ΔH; Formula (6)

[0124] Where ΔH is the deformation of the spring assembly, m. Combining the above formulas (1) to (6), we can know that

[0125]

[0126] See also Figure 3 and Figure 6 When the regulating valve opening is adjusted to a smaller value, the force balance of the tray 41 shows that:

[0127] F a1 =F k +G1-TF 12 ; Formula (7)

[0128] Combining the above formulas (1) to (4), (6) and (7), we can know that:

[0129]

[0130] See also Figure 1 , Figures 4 to 6 Step S2 also includes constructing a calculation model between the variable load rate and friction force of the regulating valve under different working conditions. Specifically, it includes the following steps:

[0131] Obtain the second force F applied by the tray 41 to the valve stem assembly 2 21 ;

[0132] Calculate the gravity G2 on the valve stem assembly 2 using the following formula:

[0133] G2=M2×g; Formula (8)

[0134] Where M2 is the sum of the design masses of the valve stem assembly 2 and the valve core 3, kg; g is the acceleration due to gravity, m / s 2 .

[0135] Calculate the steam pressure P of the steam turbine acting on the valve core 3 using the following formula:

[0136] P = (p1-p2) × S2; Formula (9)

[0137] Where p1 is the steam pressure at the steam inlet of the steam turbine regulating valve, Pa; p2 is the steam pressure at the steam outlet of the steam turbine regulating valve, Pa; S2 is the force area of ​​the valve core 3, m 2 .

[0138] Calculate the acceleration force required to lift and lower the load rate using the formula:

[0139] F a2 =M2×a; Formula (10)

[0140]

[0141] Where t is the preset time, s; △h is the stroke of the valve stem assembly 2 within the time t, m; a is the acceleration of the valve stem assembly 2, m / s 2 ;

[0142] The calculation model formula of friction force is derived, and the force analysis is carried out with the valve stem component 2 as the research object, as follows:

[0143] See also Figure 4 and Figure 6 , when the regulating valve opening is increased, the force balance of the valve stem assembly 2 shows that:

[0144] F a2 =F 21 -P-G2-f; Formula (12)

[0145] Combining the above formulas (8) to (11), we can know that

[0146]

[0147] See also Figure 5 and Figure 6 , when the regulating valve opening is increased, the force balance of the valve stem assembly 2 shows that:

[0148] F a2 =F 21 +P+G2-f; Formula (13)

[0149] Combining the above formulas (8) to (11) and (13), we can know that:

[0150]

[0151] In this embodiment, step S3 specifically includes: after the turbine control valve is installed or repaired, the control valve is subjected to a performance test under different working conditions to obtain an initial measurement value of the operating performance index. Specifically, the operating monitoring result of a specific control valve under a specific working condition is used as an example for explanation. The control valve is subjected to a performance test, and then a health index data table is established as shown in Table 2 below.

[0152] Table 2

[0153]

[0154]

[0155] It can be known that the above Table 2 is only a health indicator data table obtained under a certain working condition, and the health indicator database is a collection of health indicator data tables under all working conditions.

[0156] Step S4 specifically includes: calculating the warning threshold of the operating performance index under different working conditions, the warning threshold has a preset proportional relationship with the initial measurement value; summarizing all warning thresholds to form a warning threshold database, wherein the preset proportional relationship can be set according to the actual corresponding regulating valve, unit load or unit corresponding working condition. Specifically, taking a specific regulating valve as an example (combined with Table 2), the established warning threshold data table is as shown in Table 3 below.

[0157] Table 3

[0158]

[0159] It can be known that the above Table 3 is only a warning threshold data table obtained under a certain working condition, and the warning threshold database is a collection of warning threshold data tables under all working conditions.

[0160] As can be seen from Table 3 above, when monitoring is performed under a specific working condition, the operating time of the valve stem assembly 2 under the preset stroke is first calculated as t. When t≧1.2t0, an alarm signal is issued; when t≧1.5t0, a critical signal is issued.

[0161] When the regulating valve sends out an alarm signal or an emergency signal, the friction force f between the valve stem assembly 2 and the valve seat 1 and the elastic stiffness coefficient k of the spring assembly 5 can be further calculated. If f≧1.2f0, it can be considered that the regulating valve has a stuck fault; if k≧1.2k0, it can be considered that the spring assembly 5 of the regulating valve has a fault. Furthermore, the thrust T applied by the oil motor 43 to the diaphragm 43 can also be calculated. If T≧1.2T0, it can be determined that the oil motor 42 of the oil motor actuator 4 has a fault.

[0162] An embodiment of the present invention also provides a turbine regulating valve applicable to the turbine regulating valve performance monitoring method of any one of claims 1 to 8 above, comprising a valve seat 1, a valve stem assembly 2, a valve core 3, an oil motor actuator 4, a spring assembly 5, a force measuring device 6 and a displacement measuring device 7.

[0163] Specifically, the valve seat 1 includes a valve port 10 and a guide sleeve 11, and the valve port 10 is connected to the steam inlet 101 and the steam outlet 102; the guide sleeve 11 is slidably connected to the valve stem assembly 2, and is used to drive the valve stem assembly 2 to move axially; the valve core 3 is fixedly arranged at one end of the valve stem assembly 2, and slides synchronously with the valve stem assembly 2 to control the opening of the valve port 10; the oil motor actuator 4 includes a tray 41, and the tray 41 is connected to the end of the valve stem assembly 2 away from the valve core 3 to drive the valve stem assembly 2 to slide; one end of the spring assembly 5 is connected to the guide sleeve 11, and the other end is connected to the tray 41; the force measuring device 6 is used to measure the acting force between the tray 41 and the valve stem assembly 2; the displacement measuring device 7 includes a transmission rod 71 and a displacement sensor 72, one end of the transmission rod 71 is fixedly connected to the tray 41, and the other end is connected to the displacement sensor 72, and the displacement sensor 72 is used to measure the displacement of the transmission rod 71 sliding with the tray 41 and the time of displacement.

[0164] See also Figure 6 In this embodiment, the oil motor actuator 4 includes a tray 41, a push rod 42 and a diaphragm 43. When the oil motor supplies oil to the turbine control valve, the diaphragm 43 is subjected to force, thereby driving the diaphragm 43, the push rod 42, the diaphragm 43 and the valve stem assembly 2 to slide synchronously, and further driving the valve core 3 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 steam turbine. It can be known that when the turbine control valve is supplied with oil, the oil is input from the oil supply port 103 of the turbine control valve and output from the oil outlet 104 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. When the valve core 3 moves along the X1 direction, the valve opening of the turbine control valve increases, and the steam flow through the steam inlet 101, the valve port 10 and the steam outlet 102 increases. Correspondingly, when the valve core 3 moves along the X2 direction, the valve opening of the turbine regulating valve decreases, and the steam flow through the steam inlet 101, the valve port 10, and the steam outlet 102 decreases.

[0165] See also Figure 6 In this embodiment, the spring assembly 5 is configured as a spring, one end of the spring assembly 5 is fixedly connected to the guide sleeve 11, and the other end is fixedly connected to the oil motor actuator 4 (specifically, to the tray 41). A plurality of spring assemblies 5 are distributed in an array along the circumference of the valve stem assembly 2. Of course, in other embodiments, the central axis of the spring assembly 5 coincides with the central axis of the valve stem assembly 2, so that the force on the valve stem assembly 2 is balanced, and the valve stem assembly 2 is prevented from being subjected to a force deviating from its central axis, which affects the sliding of the valve stem assembly 2 along the guide sleeve 11. It can be known that when the elastic assembly 5 is configured as a plurality of springs, the corresponding calculation F k When solving for k, you can solve for a single spring.

[0166] There are many ways to set the force measuring device 6 and the valve stem assembly 2, which can measure the force between the valve stem assembly and the tray 41 (the first force F 12 and the second force F 21 )

[0167] See also Figure 6 and Figure 7 In this embodiment, the force measuring device 6 includes a first connecting member 61, a second connecting member 62 and a force sensitive element 63; one end of the first connecting member 61 is connected to the valve stem assembly 2, and the other end is connected to the force sensitive element 63; one end of the second connecting member 62 is connected to the tray 41, and the other end is connected to the force sensitive element 63, wherein the first connecting member 61 and the second connecting member 62 are both configured as bolts. Of course, in other embodiments, the force measuring device 6 can also be pasted to the corresponding position of the valve stem assembly 2 using a strain gauge, and can also be integrally cast with the valve stem assembly 2.

[0168] Furthermore, the force measuring device 6 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 is subjected to an external force, the elastic element inside the force measuring device 6 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.

[0169] Furthermore, in order to indicate the opening of the regulating valve, in this embodiment, the valve stem assembly 2 also includes a pointer 20 .

[0170] As can be seen from the above description, further speaking, the force measuring device 6 can be based on the principle of elastic deformation, by converting the force acting thereon into an electrical signal for output, so as to achieve accurate measurement of the force. Specifically, when the object to be measured is subjected to an external force, the elastic element inside the force measuring device 6 will produce strain, and then generate an electrical signal, which is proportional to the magnitude of the force. By processing and converting the signal, accurate measurement of the force can be achieved.

[0171] 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 104 is closed, the oil supply port 103 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 pushing the valve core 3 to increase the opening relative to the valve seat 1, and quantitatively increasing 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 104 is opened, the oil supply port 103 is closed, and the oil pressure is reduced, thereby pushing the valve core 3 to reduce the opening relative to the valve seat 1, and quantitatively reducing the amount of steam entering the steam turbine under the indication of the stroke pointer 20.

[0172] In this process, the force analysis of the valve stem assembly 2 shows that it maintains balance (and moves upward at a certain acceleration) under the gravity of the valve stem assembly 2 and the valve core 3, the friction force of the valve stem assembly 2, the force applied by the tray 41, and the steam pressure of the valve core. Taking the tray 41 as the research object, the tray 41 maintains balance (and moves upward at a certain acceleration) under the force applied to it by the valve stem assembly 2, the weight of the tray 41 itself, the force applied by the spring assembly 5, and the thrust applied by the oil motor.

[0173] 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 performance of a steam turbine regulating valve, wherein the regulating valve comprises a valve seat, a valve stem assembly, a valve core, an oil motor actuator and a spring assembly, wherein the oil motor actuator comprises a tray, and the tray is connected to the valve stem assembly; one end of the spring assembly is connected to the tray, and the other end is connected to the valve seat; It is characterized in that The following steps are involved: Divide the working conditions based on the historical operating data or design data of the control valve; Constructing a calculation model for the operating performance index of the regulating valve under different working conditions, wherein the operating performance index includes the operating time of the valve stem assembly under a preset stroke, the friction between the valve stem assembly and the valve seat, the thrust of the hydraulic motor actuator, and the elastic stiffness coefficient of the spring assembly; Obtaining initial measurement values ​​of the operating performance indicators of the control valve under different working conditions and establishing a health indicator database; Constructing a warning threshold database of the operating performance indicators under different working conditions according to the health indicator database; Obtaining a real-time value of the running time of the valve stem assembly under a preset stroke; Determine whether the real-time value of the operating time exceeds the warning threshold of the operating condition corresponding to the operating time; if so, calculate the real-time value of the friction between the valve stem assembly and the valve seat, the real-time value of the thrust exerted on the oil motor actuator, and the real-time value of the elastic stiffness coefficient of the spring assembly according to the calculation model to diagnose the fault location of the regulating valve.

2. A method for monitoring the performance of a steam turbine regulating valve according to claim 1, characterized in that: The hydraulic motor actuator also includes a connecting rod and a diaphragm; the tray is fixedly connected to the diaphragm through the connecting rod; the diaphragm is driven to slide by the hydraulic motor; The construction of the calculation model of the operating performance index of the regulating valve under different working conditions includes constructing a calculation model between the variable load rate of the regulating valve and the elastic stiffness coefficient under different working conditions; specifically includes the following steps: Obtain a first force F applied by the valve stem assembly to the tray 12 ; The gravity G1 on the tray is calculated using the following formula: G1 = M1 × g; Where M1 is the design mass of the pallet, kg; g is the acceleration due to gravity, m / s 2 ; The thrust T applied by the hydraulic motor to the diaphragm is calculated using the following formula: T=P y ×S1; P y is the oil supply pressure of the oil motor, Pa; S1 is the design area of ​​the diaphragm, m 2 ; Calculate the acceleration force F required to lift the load a1 , the calculation formula is: F a1 =M1×a; Wherein, t is the preset time, s; a is the acceleration of the valve stem assembly, m / s 2 ; △h is the stroke of the valve stem assembly in time t, m; Calculate the elastic force F applied by the spring assembly to the tray k , the calculation formula is: F k =k×ΔH; Where ΔH is the deformation of the spring assembly, m; The calculation model for deriving the elastic stiffness coefficient of the spring assembly is: When the regulating valve is in a closed state, the spring assembly is in a free state. When the turbine regulating valve is adjusted to a larger value, the calculation model formula of the elastic stiffness coefficient k is: When the turbine regulating valve is adjusted to a larger value, the calculation model formula of the elastic stiffness coefficient k is:

3. A method for monitoring the performance of a steam turbine regulating valve according to claim 2, characterized in that: The first force F applied by the valve stem assembly to the tray is obtained 12 ; Specifically including the following steps: A force measuring device is provided on the valve stem assembly to detect the first force F 12 .

4. A method for monitoring the performance of a steam turbine regulating valve according to claim 2, characterized in that: The acceleration force F required to calculate the load lifting rate a1 ,include: A displacement measuring device is installed on the tray to measure the preset time t and the stroke of the valve stem assembly within the time t.

5. A method for monitoring the performance of a steam turbine regulating valve according to any one of claims 1 to 4, characterized in that: The method of constructing a calculation model of the operating performance index of the regulating valve under different working conditions also includes constructing a calculation model between the variable load rate of the regulating valve and the friction force under different working conditions; specifically, the following steps are included: Obtain a second force F applied by the tray to the valve stem assembly 21 ; The gravity G2 on the valve stem assembly is calculated using the following formula: G2 = M2 × g; Where M2 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 ; The steam pressure P of the steam turbine acting on the valve core is calculated using the following formula: P = (p1-p2) × S2; 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; S2 is the valve core force area, m 2 ; Calculate the acceleration force F required to lift the load a2 , the calculation formula is: F a2 =M2×a; Wherein, t is the preset time, s; △h is the stroke of the valve stem assembly within t time, m; a is the acceleration of the valve stem assembly, m / s 2 ; Derive the calculation model formula of friction force f, When the turbine regulating valve is adjusted to a larger value, the calculation model formula of the friction force f is: When the turbine regulating valve is adjusted to a small value, the calculation model formula of the friction force f is:

6. A method for monitoring the performance of a steam turbine regulating valve according to claim 1, characterized in that: The method of dividing the working conditions based on the historical operating data or design data of the regulating valve comprises the following steps: Based on the historical operation data or design data of the control valve, obtain the change range of the inlet and outlet pressure difference of the control valve; According to the preset pressure difference interval, the pressure difference variation range is divided into several groups to represent different working conditions.

7. A method for monitoring the performance of a steam turbine regulating valve according to claim 1, characterized in that: The step of obtaining the initial measured values ​​of the operating performance indicators of the regulating valve under different working conditions and establishing a health indicator database specifically includes the following steps: After the steam turbine control valve is installed or repaired, a performance test is performed on the control valve under different operating conditions to obtain initial measurement values ​​of the operating performance indicators.

8. A method for monitoring the performance of a steam turbine regulating valve according to claim 7, characterized in that: The step of constructing a warning threshold database of the operating performance indicators under different working conditions according to the health indicator database specifically includes the following steps: Calculating a warning threshold of the operating performance indicator under different operating conditions, wherein the warning threshold has a preset proportional relationship with the initial measurement value; All the early warning thresholds are aggregated to form the early warning threshold database.

9. A steam turbine regulating valve applicable to the steam turbine regulating valve performance monitoring method according to any one of claims 1 to 8, characterized in that: include: Valve seat, including valve port and guide sleeve; A valve stem assembly is slidably mounted relative to the guide sleeve; A valve core is fixedly mounted at one end of the valve stem assembly and slides synchronously with the valve stem assembly to control the opening of the valve port; The hydraulic actuator comprises a tray, wherein the tray is connected to an end of the valve stem assembly away from the valve core to drive the valve stem assembly to slide; A spring assembly, one end of which is connected to the guide sleeve and the other end of which is connected to the tray; A force measuring device, used to measure the force between the tray and the valve stem assembly; The displacement measuring device comprises a transmission rod and a displacement sensor. One end of the transmission rod is fixedly connected to the tray, and the other end is connected to the displacement sensor. The displacement sensor is used to measure the displacement of the transmission rod as the tray slides and the time when the displacement occurs.

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

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