Method and system for evaluating rigidity of bearing support system of steam turbine generator unit

Abstract

The invention discloses a steam turbine generator unit bearing support system rigidity evaluation method and system, and the method comprises the steps: carrying out the external characteristic test of a bearing pedestal in the operation process of a unit, and evaluating the connection rigidity of the bearing pedestal according to a measured differential vibration value; the dynamic stiffness of the bearing seat structure is evaluated through the obtained shaft vibration and tile vibration data in the starting and speed increasing process; evaluating the connection rigidity of the bearing body by checking the three-dimensional constraint state of the bearing body; performing a modal test on the bearing body to obtain an overall modal frequency and a local modal frequency, and evaluating the dynamic stiffness of the bearing body structure through the overall modal frequency and the local modal frequency; and completing the evaluation of the rigidity of the bearing support system of the steam turbine generator unit based on each evaluation result. According to the invention, a scientific basis is provided for solving existing faults and preventing faults, a guiding direction is provided for a maintainer to formulate a maintenance scheme in advance and improve the maintenance process level, and the accuracy and the real-time performance are high.

Description

Technical Field

[0001] The present invention relates to the technical field of power machinery engineering, and particularly to a method and system for evaluating the stiffness of a bearing support system of a steam turbine generator set. Background Art

[0002] At present, vibration phenomena of structures such as bearing pedestals and bearing bodies of steam turbine generator sets are relatively common. Some units show very small shaft vibrations and very large bearing pedestal vibrations, while some units show very large shaft vibrations and very small bearing pedestal vibrations. However, during the overhaul process, it is often found that the bearing pads of the bearing bodies show serious abrasion phenomena, indicating that the bearing bodies vibrate greatly during operation. However, due to the clearance fit between the bearing body and the bearing pedestal, the vibration energy is not transmitted to the bearing pedestal. The above phenomena are all caused by the insufficient stiffness fault of the bearing support system, which seriously threatens the safe operation of the unit. There is an urgent need to form an effective method for evaluating the stiffness of the bearing support system in the field of on-site fault diagnosis and prevention.

[0003] The stiffness of the bearing support system is coupled by many stiffness units, including the connection stiffness of the bearing pedestal, the dynamic stiffness of the bearing pedestal structure, the connection stiffness of the bearing body, and the dynamic stiffness of the bearing body structure, all of which contribute to the overall stiffness of the support system. Deficiencies or defects in design (mainly affecting the dynamic stiffness of the structure) and installation (mainly affecting the connection stiffness) may lead to weak stiffness of the bearing support system, and thus larger vibrations. However, the influencing factors of the stiffness of the bearing support system are complex and the fault characteristics are not clear. It is necessary to comprehensively consider in combination with the operating conditions and overhaul conditions. At present, there is a lack of an effective and systematic evaluation method. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a method and system for evaluating the stiffness of a bearing support system of a steam turbine generator set, aiming to overcome the shortcomings and limitations of the above prior art, combine the vibration data during operation with the actual overhaul process, and diagnose in a timely and accurate manner whether the stiffness of the bearing support system is qualified.

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

[0007] In a first aspect, the present invention provides a method for evaluating the stiffness of a bearing support system of a steam turbine generator set, including: conducting an external characteristic test on the bearing housing during the operation of the unit, and evaluating the connection stiffness of the bearing housing according to the measured differential vibration value; evaluating the dynamic stiffness of the bearing housing structure by obtaining the shaft vibration and bearing vibration data during the startup speed increase process; evaluating the connection stiffness of the bearing body by examining the three-dimensional constraint state of the bearing body; conducting a modal test on the bearing body to obtain the overall modal frequency and local modal frequency, and evaluating the dynamic stiffness of the bearing body structure through the overall modal frequency and local modal frequency; and completing the evaluation of the stiffness of the bearing support system of the steam turbine generator set based on the results of each evaluation.

[0008] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of the steam turbine generator set according to the present invention, wherein: the evaluation of the connection stiffness of the bearing housing includes:

[0009] Obtaining the comprehensive external characteristic data of the bearing housing of the evaluated bearing of the steam turbine generator set during operation;

[0010] Analyzing the external characteristic data by the matrix difference method to obtain the vibration difference matrix of the measurement points in different height planes and the vibration difference matrix of the measurement points in the same height plane;

[0011] If all the edge elements of the above matrix are less than the first threshold, it is determined that the connection stiffness of the bearing housing is qualified, otherwise it indicates that the stiffness of the bearing support system is unqualified.

[0012] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of the steam turbine generator set according to the present invention, wherein: the evaluation of the dynamic stiffness of the bearing housing structure includes:

[0013] Obtaining the shaft vibration and bearing vibration data of the evaluated bearing of the steam turbine generator set during the most recent startup process, and obtaining the resonance peak values of the shaft vibration and bearing vibration and the corresponding resonance speeds during the speed increase process;

[0014] If all the resonance peak values of the bearing vibration are less than the second threshold, and at the same time the avoidance rate between the peak speed and the operating speed is greater than the third threshold, it is determined that the dynamic stiffness of the bearing housing structure is qualified;

[0015] Otherwise, find the resonance speed of the bearing vibration with a deviation from the shaft vibration resonance speed greater than the fourth threshold. If such a speed exists, and its corresponding bearing vibration peak value is less than the fifth threshold, and at the same time the avoidance rate between the peak speed and the operating speed is greater than the third threshold, it is determined that the dynamic stiffness of the bearing housing structure is qualified, otherwise it indicates that the stiffness of the bearing support system is unqualified.

[0016] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of the steam turbine generator set according to the present invention, wherein: the evaluation of the connection stiffness of the bearing body includes:

[0017] During shutdown, uncover the bearing housing cover and recheck the contact ratio C of the bearing body shims to the spherical surface of the spherical support 1 , the contact ratio C of the left and right inserts to the sides of the bearing body and the bearing housing 21L , C 22L , C 21R , C 22R , the contact ratio C of the left and right packing blocks to the bearing housing cover 3L , C 3R ;

[0018] If the above connection contact ratios all exceed the sixth threshold, it is determined that the connection stiffness of the bearing body is qualified; otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0019] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of a steam turbine generator set according to the present invention, wherein: evaluating the dynamic stiffness of the bearing body structure includes:

[0020] Using the hammer impact method to conduct overall and local modal tests on the bearing body structure, and respectively obtaining the overall modal frequency sequence {ΩA n3} and the local modal frequency sequence {ΩB n4} of the bearing body;

[0021] If the elements in {ΩA n3} and {ΩB n4} are all avoided from the working speed frequency by more than the third threshold, it is determined that the dynamic stiffness of the bearing body structure is qualified, that is, the stiffness of the bearing support system is qualified; otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0022] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of a steam turbine generator set according to the present invention, wherein: it further includes:

[0023] Respectively performing spectral analysis on the acquired data to obtain the amplitude and phase data of the first harmonic components of the shaft vibration and bearing vibration under different speed conditions, and sequentially storing the speed, the first harmonic amplitude of the shaft vibration, the first harmonic phase of the shaft vibration, the first harmonic amplitude of the bearing vibration, and the first harmonic phase of the bearing vibration into the sequences {R n}, {SA n}, {SP n}, {BA n}, {BP n};

[0024] Respectively performing trend analysis on the shaft vibration data and the bearing vibration data with respect to the speed to obtain the resonance peaks and corresponding resonance speeds of the shaft vibration and the bearing vibration during the speed-up process, and respectively storing them into the corresponding sequences.

[0025] As a preferred embodiment of the method for evaluating the stiffness of the bearing support system of a steam turbine generator set according to the present invention, wherein: the calculation of the connection contact ratio includes:

[0026] Define the connection contact rate as the contact area / design area, and calculate the connection contact rate C of the bearing shim and the spherical surface of the spherical support respectively 1 = A 1 / B 1 , the connection contact rate C of the left and right side plug-ins and the sides of the bearing and the bearing housing 21L = A 21L / B 21L , C 22L = A 22L / B 22L , C 21R = A 21R / B 21R , C 22R = A 22L / B 22R , the connection contact rate C of the left and right side pressing blocks and the bearing housing cover 3L = A 3L / B 3L , C 3R = A 3R / B 3R ;

[0027] Among them, A 1 , A 21L , A 22L , A 21R , A 22R , A 3L , A 3R are the contact areas of the bearing shim and the spherical surface of the spherical support, the contact area of the left side plug-in and the bearing side, the contact area of the left side plug-in and the bearing housing side, the contact area of the right side plug-in and the bearing side, the contact area of the right side plug-in and the bearing housing side, the contact area of the left side pressing block and the bearing housing cover, and the contact area of the right side pressing block and the bearing housing cover respectively, and B 1 , B 21L , B 22L , B 21R , B 22R , B 3L , B 3R are the design areas of the spherical support, the right side design area of the left side plug-in, the left side design area of the left side plug-in, the left side design area of the right side plug-in, the right side design area of the right side plug-in, the design area of the left side pressing block, and the design area of the right side pressing block respectively.

[0028] In a second aspect, the present invention provides a stiffness evaluation system for a bearing support system of a steam turbine generator set, including:

[0029] A bearing housing connection stiffness evaluation module, which is used to perform an external characteristic test on the bearing housing during the operation of the unit, and evaluate the connection stiffness of the bearing housing according to the measured differential vibration value;

[0030] The bearing housing structure dynamic stiffness evaluation module is used to evaluate the dynamic stiffness of the bearing housing structure by obtaining the shaft vibration and bearing vibration data during the start-up speed increase process;

[0031] The bearing body connection stiffness evaluation module is used to evaluate the bearing body connection stiffness by using the three-dimensional constraint state of the bearing body inspection;

[0032] The bearing body structure dynamic stiffness evaluation module is used to conduct a modal test on the bearing body to obtain the overall modal frequency and local modal frequency, and evaluate the bearing body structure dynamic stiffness through the overall modal frequency and local modal frequency;

[0033] The overall evaluation result acquisition module is used to complete the evaluation of the stiffness of the bearing support system of the steam turbine generator set based on the results of each evaluation.

[0034] In a third aspect, the present invention provides an electronic device, including:

[0035] A memory and a processor;

[0036] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the method for evaluating the stiffness of the bearing support system of the steam turbine generator set are implemented.

[0037] In a fourth aspect, the present invention provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the steps of the method for evaluating the stiffness of the bearing support system of the steam turbine generator set are implemented.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a method for evaluating the stiffness of the bearing support system of a steam turbine generator set. During specific operations, relevant vibration data during the start-up and operation processes are obtained for feature analysis, and combined with relevant test data during the shutdown and maintenance period, to identify whether the bearing support system is normal, providing a scientific basis for solving existing faults and preventing the occurrence of faults, providing a guiding direction for maintenance personnel to formulate maintenance plans in advance and improve the maintenance technology level, with high accuracy and real-time performance. At the same time, the present invention can directly use the data of the TDM system randomly equipped with the steam turbine generator set, cooperate with a simple handheld vibration meter, with simple operating conditions, convenient for on-site implementation and reliable analysis results. It has accurately diagnosed the fault of insufficient bearing support stiffness of the steam turbine generator set in on-site fault analysis many times, ensuring the safety of the equipment and creating huge economic and social benefits for the power plant. Description of the Drawings

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0040] Figure 1 It is a schematic diagram of the overall process logic of the stiffness evaluation method for the bearing support system of a steam turbine generator set according to an embodiment of the present invention;

[0041] Figure 2 It is a detailed step flowchart of the stiffness evaluation method for the bearing support system of a steam turbine generator set according to an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the measurement point division of the bearing housing for the stiffness evaluation method of the bearing support system of a steam turbine generator set according to an embodiment of the present invention (only the measurement points visible in this viewing direction are listed);

[0043] Figure 4 It is a schematic diagram of the variation trend of the amplitude and phase of shaft vibration / housing vibration with the rotational speed for the stiffness evaluation method of the bearing support system of a steam turbine generator set according to an embodiment of the present invention. Detailed Embodiments

[0044] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will provide a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0045] Embodiment 1

[0046] Refer to Figure 1 - Figure 2 For an embodiment of the present invention, a stiffness evaluation method for the bearing support system of a steam turbine generator set is provided. As Figure 1 shown, it specifically includes the following steps:

[0047] S100: During the operation of the unit, conduct an external characteristic test on the bearing housing, and evaluate the connection stiffness of the bearing housing according to the measured differential vibration value;

[0048] S200: Evaluate the dynamic stiffness of the bearing housing structure based on the shaft vibration and housing vibration data obtained during the startup speed increase process;

[0049] S300: Evaluate the connection stiffness of the bearing body by checking the three-dimensional constraint state of the bearing body;

[0050] S400: Conduct a modal test on the bearing body to obtain the overall modal frequency and local modal frequency, and evaluate the dynamic stiffness of the bearing body structure based on the overall modal frequency and local modal frequency;

[0051] S500: Complete the evaluation of the stiffness of the bearing support system of the steam turbine generator set based on the results of each evaluation.

[0052] It should be noted that the present invention provides a method for evaluating the stiffness of the bearing support system of a steam turbine generator set. During specific operation, by obtaining relevant vibration data during the start-up and operation processes for feature analysis and combining with relevant test data during the shutdown and maintenance periods, it is possible to identify whether the bearing support system is normal, providing a scientific basis for solving existing faults and preventing the occurrence of faults, providing a guiding direction for maintenance personnel to formulate maintenance plans in advance and improve the maintenance technology level, with relatively high accuracy and real-time performance. At the same time, the present invention can directly use the data of the TDM system randomly equipped with the steam turbine generator set, in cooperation with a simple handheld vibration meter, with simple operating conditions, convenient for on-site implementation and reliable analysis results. It has accurately diagnosed the fault of insufficient bearing support stiffness of the steam turbine generator set in on-site fault analysis many times, ensuring the safety of the equipment and creating huge economic and social benefits for the power plant.

[0053] In the embodiment of the present application, as Figure 2 shown, the above-mentioned step S100 conducts an external characteristic test on the bearing pedestal during the operation of the unit, and the evaluation of the connection stiffness of the bearing pedestal according to the measured differential vibration value includes:

[0054] Obtain the comprehensive external characteristic data of the bearing pedestal of the bearing to be evaluated in the steam turbine generator set during operation;

[0055] Analyze the external characteristic data through the matrix difference method to obtain the vibration difference matrix of the measurement points on different height planes and the vibration difference matrix of the measurement points on the same height plane;

[0056] If all the edge elements of the above matrix are less than the first threshold, it is determined that the connection stiffness of the bearing pedestal is qualified; otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0057] Specifically, the first threshold in the present application is 10 μm;

[0058] Specifically, obtaining the comprehensive external characteristic data of the bearing pedestal of the bearing to be evaluated in the steam turbine generator set during operation includes positions such as the foundation, soleplate, foot, and horizontal split surface. Define the bearing O-XYZ coordinate system facing the engine head, and divide the bearing pedestal foundation, soleplate, and foot into a total of 3 horizontal planes A, B, and C in sequence from bottom to top along the Y direction, and define the position 3 cm below the horizontal split surface of the bearing pedestal as horizontal plane D 1 , and define the position 3 cm above the horizontal split surface as horizontal plane D 2, define three dividing planes to divide it at the positions of the two end faces and the middle face of the horizontal plane C along the X-axis direction. The dividing plane numbers are sequentially recorded as CXi (i = 1, 2, 3). Define three dividing planes to divide it at the positions of the two end faces and the middle face of the horizontal plane C along the Z-axis direction. The dividing plane numbers are sequentially recorded as CZj (j = 1, 2, 3). Similarly, divide the horizontal planes A, B, D 1 , D 2 one by one. Denote the intersection points of the horizontal planes A to D 2 and the corresponding dividing planes as measurement points A ij , B ij , C ij , D 1ij , D 2ij , measure the vertical vibration values of each measurement point A ij , B ij , C ij and record them as a ij , b ij , c ij , measure the horizontal vibration values of each measurement point D 1ij , D 2ij and record them as d 1ij , d 2ij . Among them, the vibration values of the measurement points that are inconvenient to measure due to position limitations are recorded as 0 and stored in matrices A, B, C, D 1 , D 2 respectively;

[0059] Specifically, define the edge elements of the p-order matrix A p×p as the elements in the first row A[1, :], the p-th row A[p, :], the first column A[:, 1], and the p-th column A[:, p] of the matrix A;

[0060] Specifically, define the matrices ΔAB = B - A, ΔBC = C - B, ΔD = D 2 - D 1 . For any edge element, it satisfies A[i, j] < 10, ΔAB[i, j] < 10, ΔBC[i, j] < 10, ΔD[i, j] < 10. At the same time, for any two edge elements, it satisfies |B[i 0 , j 0 - B[i 1 , j 1 | < 10, |C[i 0 , j 0 - C[i 1 , j 1 | < 10, |D 1 [i 0 , j 0 - D 1 [i 1 , j1 | < 10, | D 2 [i 0 , j 0 -D 2 [i 1 , j 1 | < 10, it is considered that the connection stiffness of the bearing housing is qualified, and the dynamic stiffness evaluation of the bearing housing structure continues. Otherwise, it is considered that the stiffness of the bearing support system is unqualified.

[0061] It should be noted that the above step S100 directly reflects the connection stiffness of the bearing housing under actual operating conditions through the external characteristic test of the bearing housing during the operation of the unit, can accurately identify the stiffness changes caused by operating load and environmental factors, ensure that the evaluation results are highly consistent with the actual working conditions, and is conducive to timely discovering potential problems and taking corresponding measures.

[0062] In the embodiment of the present application, the above step S200 evaluates the dynamic stiffness of the bearing housing structure through the shaft vibration and bearing vibration data obtained during the start-up speed increase process, including:

[0063] Obtain the shaft vibration and bearing vibration data of the bearing to be evaluated in the steam turbine generator unit during the most recent start-up process, and obtain the resonance peak values of the shaft vibration and bearing vibration and the corresponding resonance speeds during the speed increase process;

[0064] If all the resonance peak values of the bearing vibrations are less than the second threshold, and at the same time the avoidance rate between the peak speed and the operating speed is greater than the third threshold, it is determined that the dynamic stiffness of the bearing housing structure is qualified;

[0065] Otherwise, find the resonance speed of the bearing vibration with a deviation from the resonance speed of the shaft vibration greater than the fourth threshold. If such a speed exists, and its corresponding bearing vibration peak value is less than the fifth threshold, and at the same time the avoidance rate between the peak speed and the operating speed is greater than the third threshold, it is determined that the dynamic stiffness of the bearing housing structure is qualified. Otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0066] Specifically, the second threshold in the present application is 80 μm, the third threshold is 10%, the fourth threshold is 5%, and the fifth threshold is 60 μm;

[0067] Specifically, obtain the shaft vibration and bearing vibration data of the bearing to be evaluated in the steam turbine generator unit during the most recent start-up process, perform spectral analysis respectively, obtain the amplitude and phase data of the fundamental frequency components of the shaft vibration and bearing vibration under different speed conditions, and store the speed, the fundamental frequency amplitude of the shaft vibration, the fundamental frequency phase of the shaft vibration, the fundamental frequency amplitude of the bearing vibration, and the fundamental frequency phase of the bearing vibration into the sequences {R n}, {SA n}, {SP n}, {BA n}, {BP n} in ascending order of speed;

[0068] Specifically, perform a trend analysis of the shaft vibration with respect to the rotational speed to find R i , R imax , R imin ∈{R n}, where R imax is the rotational speed value closest to R i +100, that is, for any R j0 ∈{R n}, there is |R imax -(R i +100)|<|R j0 -(R i +100)|, R imin is the rotational speed value closest to R i -100, that is, for any R j1 ∈{R n}, there is |R imin -(R i -100)|<|R j1 -(R i -100)|, satisfying that for R m1 ∈{R n}(imin≤m1≤imax, m1≠i), there is SA m1 <SA i , and for SP m1 ∈{SP n}(imin≤m1≤imax, m1≠i), there is SP m1 <SP m1+1 , and at the same time SP imax -SP imin ≥60, then R i is called the shaft vibration resonance rotational speed and is denoted as RS pi , the corresponding vibration is called the shaft vibration resonance peak SA pi , the phase is denoted as SP pi , and they are respectively stored in the sequences {RSp n1}, {SAp n1}, {SPp n1};

[0069] Specifically, perform a trend analysis of the bearing vibration with respect to the rotational speed to find R u , R umax , R umin ∈{R n}, where R umax is the rotational speed value closest to R u +100, that is, for any R j2 ∈{R n}, there is |R umax -(R u +100)|<|Rj2 -(R u +100)|, where R umin is the rotational speed value closest to R u -100, that is, for any R j3 ∈{R n}, there is always |R umin -(R u -100)| < |R j3 -(R u -100)|, satisfying that for R m2 ∈{R n} (umin ≤ m2 ≤ umax, m ≠ u), there is always BA m2 < BA u , and for BP m2 ∈{BP n} (umin ≤ m2 ≤ umax, m ≠ u), there is always BP m2 < BP m2+1 . At the same time, BP umax - BP umin ≥ 60, then R u is called the bearing vibration resonance rotational speed and is denoted as RB pu , the corresponding vibration is called the bearing vibration resonance peak BA pu , and the phase is denoted as BP pu , and they are respectively stored in the sequences {RBp n2}, {BAp n2}, {BPp n2};

[0070] Specifically, if all elements in {BAp n2} are less than 80 μm, it is considered that the dynamic stiffness of the bearing housing structure is qualified. Otherwise, in the bearing vibration resonance rotational speed sequence {RBp n2}, find the elements RBp n1 that have a deviation greater than 5% from all elements in the shaft vibration resonance rotational speed sequence {RSp ru0}, that is, for any RS pi ∈{RSp n1}, there is always |RBp ru0 - RS pi | / |RS pi | greater than 5%. If RBp ru0 exists, and there is always BAp ru0 < 60 μm, and it satisfies |RBp ru0 - 3000| / 3000 > 10%, then it is considered that the dynamic stiffness of the bearing housing structure is qualified, and the evaluation of the connection stiffness of the bearing body continues. Otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0071] It should be noted that the above step S200 evaluates the dynamic stiffness of the bearing housing structure by analyzing the shaft vibration and bearing vibration data during the startup speed increase process, which can capture the dynamic response characteristics during the transition of the equipment from the stationary state to the operating state, effectively identify the resonance and other dynamic problems that may occur during the startup process, and provide a basis for optimizing the startup procedure and preventive maintenance.

[0072] In the embodiment of the present application, the above step S300 evaluates the connection stiffness of the bearing body by using the three-dimensional constraint state of the bearing body, including:

[0073] During the shutdown period, open the bearing housing cover and recheck the contact rate C of the bearing body soleplate and the spherical surface connection of the spherical bracket 1 , the contact rate C of the left and right inserts with the bearing body and the side of the bearing housing 21L , C 22L , C 21R , C 22R , the contact rate C of the left and right pressing blocks with the bearing housing cover 3L , C 3R ;

[0074] If the above connection contact rates all exceed the sixth threshold, it is determined that the connection stiffness of the bearing body is qualified; otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0075] Specifically, the sixth threshold in the present application is 80%;

[0076] Specifically, during the shutdown period, open the bearing housing cover, and respectively obtain the contact area A of the bearing soleplate and the spherical surface of the spherical bracket through the red lead powder test 1 , the contact area A of the left insert with the bearing and the side of the bearing housing 21L , A 22L , the contact area A of the right insert with the bearing and the side of the bearing housing 21R , A 22R , the contact area A of the left pressing block with the bearing housing cover 3L , the contact area A of the right pressing block with the bearing housing cover 3R ;

[0077] Specifically, define the connection contact rate as the contact area / design area, and respectively calculate the connection contact rate C of the bearing soleplate and the spherical surface of the spherical bracket 1 = A 1 / B 1 , the connection contact rate C of the left and right inserts with the bearing and the side of the bearing housing 21L = A 21L / B 21L , C 22L = A 22L / B 22L , C 21R = A 21R / B 21R , C22R = A 22L / B 22R and the connection contact rate C between the left and right side pressing blocks and the bearing housing cover 3L = A 3L / B 3L and C 3R = A 3R / B 3R , where B 1 , B 21L , B 22L , B 21R , B 22R , B 3L , B 3R are respectively the designed area of the spherical support, the designed area on the right side of the left plug-in, the designed area on the left side of the left plug-in, the designed area on the left side of the right plug-in, the designed area on the right side of the right plug-in, the designed area of the left pressing block, and the designed area of the right pressing block;

[0078] Specifically, if C 1 , C 21L , C 22L , C 21R , C 22R , C 3L , C 3R are all ≥ 80%, it is considered that the dynamic stiffness of the bearing seat structure is qualified, and the evaluation of the dynamic stiffness of the bearing body structure continues. Otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0079] It should be noted that the above step S300 evaluates the connection stiffness by checking the three-dimensional constraint state of the bearing body, can accurately determine the actual constraint conditions and installation accuracy of the bearing in each direction, ensure its stable position and performance during operation, and effectively prevent abnormal vibration and wear caused by installation errors or structural looseness.

[0080] In the embodiment of the present application, the above step S400 performs a modal test on the bearing body to obtain the overall modal frequency and local modal frequency, and the evaluation of the dynamic stiffness of the bearing body structure by the overall modal frequency and local modal frequency includes:

[0081] The overall and local modal tests are performed on the bearing body structure by the hammering method to obtain the overall modal frequency sequence {ΩA n3} and the local modal frequency sequence {ΩB n4} of the bearing body respectively;

[0082] If the elements in {ΩA n3} and {ΩB n4} all have a bypass rate from the working speed frequency exceeding the third threshold, it is determined that the dynamic stiffness of the bearing body structure is qualified, that is, the stiffness of the bearing support system is qualified. Otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0083] Specifically, the hammering method is used to conduct the overall and local modal tests on the bearing body structure, and the overall modal frequency distribution data ΩA of the bearing body is obtained. i and the local modal frequency distribution data ΩB i , which are respectively stored in the sequences {ΩA n3} and {ΩB n4};

[0084] Specifically, if for any ΩA i ∈{ΩA n3}, ΩB i ∈{ΩB n4}, and both |ΩA i - 50| / 50 > 10%, |ΩB i - 50| / 50 > 10%, then it is considered that the stiffness of the bearing support system is qualified; otherwise, it indicates that the stiffness of the bearing support system is unqualified.

[0085] It should be noted that the above step S400 can accurately identify the natural frequencies and vibration modes of the structure by conducting modal tests on the bearing body, which helps to discover potential resonance risks and structural weaknesses, and provides key data support for optimizing the design and improving the system stability.

[0086] Embodiment 2

[0087] Referring to Figure 3 and Figure 4 , based on the previous embodiment, this embodiment provides an application example of a method and system for evaluating the stiffness of a bearing support system for a steam turbine generator set to verify and illustrate the technical effects adopted in this method.

[0088] Taking the high-pressure cylinder bearing of a 1000MW unit in a certain power plant as an example in this embodiment, during the operation of the unit, as Figure 3 shown, the measuring points of the bearing pedestal to be evaluated are divided, and the measured external characteristic data of the bearing pedestal are sequentially stored in matrices A to D 2 as follows: The specific data are as follows:

[0089]

[0090] Calculate the difference matrix as follows:

[0091]

[0092] If any of the edge elements in matrices A, △AB, △BC, and △D < 10, and at the same time, the absolute value of the difference between any two edge elements in matrices B, C, and D 1 , D 2 < 10, it is determined that the connection stiffness of the bearing pedestal is qualified, and proceed to the next step.

[0093] Obtain the shaft vibration and bearing vibration data of the bearings of the steam turbine generator set during the most recent startup process, and perform spectral analysis separately to obtain the amplitude and phase data of the first harmonic components of the shaft vibration and bearing vibration under different rotational speed conditions. Since the amount of data is relatively large and there are many elements in the initial sequence, as Figure 4 shown, list the meanings expressed by each sequence in the form of a graph.

[0094] Conduct a trend analysis of the shaft vibration with respect to the rotational speed. When R 173 = 1664, (i = 173), R 188 = 1760 (imax = 188), R 157 = 1568 (imin = 157), within the rotational speed range of 1568 - 1760 rpm, SA 173 = 180 has the maximum amplitude, and within this range {SP n} increases monotonically. At the same time, SP 188 = 183, SP 157 = 106, SP 188 - SP 157 = 77 > 60. It is considered that the resonance rotational speed of the shaft vibration is 1664 rpm, the resonance peak value is 183 μm, and the phase is 145°. Store them in the sequences {RSp n1}, {SAp n1}, {SPp n1}; Conduct a trend analysis of the bearing vibration with respect to the rotational speed. When R 108 = 1289, (i = 108), R 126 = 1388 (imax = 126), R 91 = 1192 (imin = 91), within the rotational speed range of 1192 - 1388 rpm, SA 108 = 21 has the maximum amplitude, and within this range {SP n} increases monotonically. At the same time, SP 126 = 255, SP 91 = 176, SP 126 - SP 91 = 79 > 60. It is considered that the resonance rotational speed 1 of the bearing vibration is 1289 rpm, the resonance peak value is 21 μm, and the phase is 206°. Similarly, find that the resonance rotational speed 2 of the bearing vibration is 1540 rpm, the resonance peak value is 18 μm, and the phase is 292°. The resonance rotational speed 3 of the bearing vibration is 1825 rpm, the resonance peak value is 7 μm, and the phase is 265°. The resonance rotational speed 4 of the bearing vibration is 2195 rpm, the resonance peak value is 22 μm, and the phase is 290°. Store them in the sequences {RBp n2}, {BAp n2}, {BPp n2} respectively.

[0095] It can be seen that {BApn2 If all elements in} are less than 80 μm, it is considered that the dynamic stiffness of the bearing housing structure is qualified and the next step can be entered.

[0096] During the shutdown for maintenance, the bearing housing cover is removed, and the contact rates of each connection surface are obtained through red lead powder tests as follows: the contact rate C of the bearing shim with the spherical surface of the spherical support 1 = 90%, the contact rate C of the left plug-in with the bearing and the side of the bearing housing 21L = 70%, C 22L = 75%, the contact area C of the right plug-in with the bearing and the side of the bearing housing 21R = 50%, C 22R = 60%, the contact rate C of the left pressing block with the bearing housing cover 3L = 85%, the contact rate C of the right pressing block with the bearing housing cover 3R = 80%;

[0097] It can be seen that the contact rates of the left and right plug-ins are less than 80%, and it is considered that the stiffness of the bearing support system is unqualified.

[0098] As can be seen from the above implementation content, in the specific operation of the present invention, by obtaining the relevant vibration data during the start-up and operation process for feature analysis and combining with the relevant test data during the shutdown for maintenance, it is possible to identify whether the bearing support system is normal, provide a scientific basis for solving existing faults and preventing the occurrence of faults, provide a guiding direction for maintenance personnel to formulate maintenance plans in advance and improve the maintenance technology level, and has high accuracy and real-time performance. At the same time, the present invention can directly use the data of the TDM system randomly equipped with the steam turbine generator set, cooperate with a simple handheld vibration meter, has simple operating conditions, is convenient for on-site implementation and the analysis results are reliable. It has accurately diagnosed the fault of insufficient bearing support stiffness of the steam turbine generator set in on-site fault analysis many times, ensuring the safety of the equipment and creating huge economic and social benefits for the power plant at the same time.

[0099] Embodiment 3

[0100] In this embodiment, a stiffness evaluation system for the bearing support system of a steam turbine generator set is provided, including:

[0101] A bearing housing connection stiffness evaluation module, which is used to conduct an external characteristic test of the bearing housing during the operation of the unit and evaluate the bearing housing connection stiffness according to the measured differential vibration value;

[0102] A bearing housing structural dynamic stiffness evaluation module, which is used to evaluate the bearing housing structural dynamic stiffness by obtaining the shaft vibration and bearing vibration data during the start-up and speed-up process;

[0103] A bearing body connection stiffness evaluation module, which is used to evaluate the bearing body connection stiffness by using the three-dimensional constraint state of the bearing body;

[0104] The bearing body structure dynamic stiffness evaluation module is used to conduct a modal test on the bearing body to obtain the overall modal frequency and local modal frequency, and evaluate the dynamic stiffness of the bearing body structure through the overall modal frequency and local modal frequency;

[0105] The overall evaluation result acquisition module is used to complete the evaluation of the stiffness of the bearing support system of the steam turbine generator unit based on the results of each evaluation.

[0106] It should be noted that the technical solution of the system for evaluating the stiffness of the bearing support system of the steam turbine generator unit belongs to the same concept as the technical solution of the above method for evaluating the stiffness of the bearing support system of the steam turbine generator unit. For the details not described in detail in the technical solution of the system for evaluating the stiffness of the bearing support system of the steam turbine generator unit in this embodiment, reference can be made to the description of the technical solution of the above method for evaluating the stiffness of the bearing support system of the steam turbine generator unit.

[0107] The above-mentioned unit modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so as to facilitate the processor to call and execute the operations corresponding to the above modules.

[0108] This embodiment also provides an electronic device, which includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a carrier network, NFC (Near Field Communication) or other technologies. When the computer program is executed by the processor, it realizes a method for evaluating the stiffness of the bearing support system of a steam turbine generator unit. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball or a touchpad set on the shell of the computer device, or an external keyboard, a touchpad or a mouse, etc.

[0109] This embodiment also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it realizes the method proposed in the above embodiment.

[0110] The storage medium proposed in this embodiment and the method proposed in the above embodiment belong to the same inventive concept. The technical details not described in detail in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0111] From the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software and necessary general-purpose hardware. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disc of a computer, etc., and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute the method of the embodiments of the present invention.

[0112] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

[0113] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present application can be implemented in various computer languages.

[0114] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0115] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means embodying the functionality specified in the flowchart(s) Figure 1 a flowchart or flowcharts and / or block(s) Figure 1 a block or blocks.

[0116] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing steps for implementing the functionality specified in the flowchart(s) Figure 1 a flowchart or flowcharts and / or block(s) Figure 1 a block or blocks.

[0117] Although the preferred embodiments of the present application have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to cover the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

[0118] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

1. A method for evaluating the stiffness of a bearing support system of a steam turbine generator set, characterized in that: include: Carry out external characteristic test of bearing seat during the operation of the unit, and evaluate the bearing seat connection stiffness based on the measured differential vibration value; The dynamic stiffness of the bearing seat structure is evaluated by obtaining the shaft vibration and bearing vibration data during the startup and speed-up process; The bearing body connection stiffness is evaluated by checking the three-dimensional constraint state of the bearing body; Performing a modal test on the bearing body to obtain an overall modal frequency and a local modal frequency, and evaluating the dynamic stiffness of the bearing body structure through the overall modal frequency and the local modal frequency; Based on the results of each assessment, the assessment of the stiffness of the turbine generator set bearing support system is completed.

2. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 1, characterized in that: The evaluation of the bearing housing connection stiffness includes: Obtain comprehensive external characteristic data of the bearing seat of the steam turbine generator set during operation; The external characteristic data are analyzed by matrix difference method to obtain the vibration difference matrix of the measuring points in planes with different heights and the vibration difference matrix of the measuring points in planes with equal heights. If the edge elements of the above matrix are all smaller than the first threshold, it is judged that the bearing seat connection stiffness is qualified, otherwise it means that the bearing support system stiffness is unqualified.

3. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 2, wherein: The evaluation of the dynamic stiffness of the bearing housing structure includes: Obtain the shaft vibration and bearing vibration data of the turbine generator set evaluated during the most recent startup process, and obtain the resonance peak values ​​of the shaft vibration and bearing vibration and the corresponding resonance speed during the speed-up process; If all bearing vibration resonance peaks are less than the second threshold, and the peak speed and operating speed avoidance ratio are greater than the third threshold, the dynamic stiffness of the bearing seat structure is judged to be qualified; Otherwise, look for the bearing vibration resonance speed whose deviation from the shaft vibration resonance speed is greater than the fourth threshold. If this speed exists and its corresponding bearing vibration peak is less than the fifth threshold, and the peak speed and working speed avoidance rate is greater than the third threshold, then the dynamic stiffness of the bearing seat structure is judged to be qualified. Otherwise, it means that the stiffness of the bearing support system is unqualified.

4. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 3, characterized in that: The evaluation of the bearing body connection stiffness comprises: During downtime, open the bearing box cover and check the contact rate C1 between the bearing body shim and the spherical surface of the spherical bracket, and the contact rate C1 between the left and right plug-ins and the bearing body and the side of the bearing box. 21L , C 22L , C 21R , C 22R , the contact rate between the left and right pressure blocks and the bearing box cover C 3L , C 3R ; If the above connection contact rates all exceed the sixth threshold value, it is judged that the connection stiffness of the bearing body is qualified, otherwise it means that the stiffness of the bearing support system is unqualified.

5. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 4, characterized in that: The evaluation of the dynamic stiffness of the bearing structure includes: The overall and local modal tests of the bearing structure were carried out by hammering method, and the overall modal frequency series of the bearing body {ΩA n3 } and the local modal frequency series {ΩB n4 }; If {ΩA n3 } and {ΩB n4 If the elements in} all exceed the third threshold value with the working speed frequency avoidance rate, it is judged that the dynamic stiffness of the bearing body structure is qualified, that is, the stiffness of the bearing support system is qualified; otherwise, it is indicated that the stiffness of the bearing support system is unqualified.

6. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 3, characterized in that: Also includes: The acquired data are analyzed by spectrum analysis to obtain the amplitude and phase data of the first-time frequency component of shaft vibration and bearing vibration under different speed conditions, and the speed, the first-time frequency amplitude of shaft vibration, the first-time frequency phase of shaft vibration, the first-time frequency amplitude of bearing vibration, and the first-time frequency phase of bearing vibration are stored in the array {R n }、{SA n }、{SP n }, {BA n }, {BP n }middle; The shaft vibration data and bearing vibration data are analyzed for the rotational speed trend, and the resonance peak values ​​and corresponding resonance rotational speeds of the shaft vibration and bearing vibration during the speed increase process are obtained and stored in the corresponding series respectively.

7. The method for evaluating the stiffness of a bearing support system of a steam turbine generator set according to claim 4, characterized in that: The calculation of the connection contact rate includes: The connection contact rate is defined as contact area / design area, and the connection contact rate between the bearing pad and the spherical surface of the spherical bracket is calculated as C1=A1 / B1, the connection contact rate between the left and right side plug-ins and the bearing and the side of the bearing box is calculated as C 21L =A 21L / B 21L , C 22L =A 22L / B 22L , C 21R =A 21R / B 21R , C 22R =A 22L / B 22R , the contact rate between the left and right side pressure blocks and the bearing box cover C 3L =A 3L / B 3L , C 3R =A 3R / B 3R ; Among them, A1, A 21L , A 22L , A 21R , A 22R , A 3L , A 3R They are the contact area between the bearing washer and the spherical bracket, the contact area between the left plug-in and the bearing side, the contact area between the left plug-in and the bearing box side, the contact area between the right plug-in and the bearing side, the contact area between the right plug-in and the bearing box side, the contact area between the left pressure block and the bearing box cover, and the contact area between the right pressure block and the bearing box cover, B1, B 21L , B 22L , B 21R , B 22R , B 3L , B 3R They are the design area of ​​the spherical bracket, the design area of ​​the right side of the left plug-in, the design area of ​​the left side of the left plug-in, the design area of ​​the left side of the right plug-in, the design area of ​​the right side of the right plug-in, the design area of ​​the left pressure block, and the design area of ​​the right pressure block.

8. A system using the method for evaluating the stiffness of a bearing support system of a steam turbine generator set as claimed in any one of claims 1 to 7, characterized in that: include: The bearing seat connection stiffness evaluation module is used to perform external characteristic tests of the bearing seat during the operation of the unit and evaluate the bearing seat connection stiffness based on the measured differential vibration values; The bearing seat structure dynamic stiffness assessment module is used to assess the bearing seat structure dynamic stiffness by acquiring shaft vibration and bearing vibration data during the startup and speed-up process; A bearing body connection stiffness evaluation module is used to evaluate the bearing body connection stiffness by checking the three-dimensional constraint state of the bearing body; A bearing body structure dynamic stiffness evaluation module is used to perform a modal test on the bearing body to obtain an overall modal frequency and a local modal frequency, and to evaluate the bearing body structure dynamic stiffness through the overall modal frequency and the local modal frequency; The overall evaluation result acquisition module is used to complete the evaluation of the stiffness of the bearing support system of the steam turbine generator set based on the results of each evaluation.

9. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the method according to claims 1 to 7 are implemented.

10. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that: When the computer executable instructions are executed by a processor, the steps of the method according to claims 1 to 7 are implemented.

Images