Generator stator foot load adjustment test method based on vibration control

Abstract

The invention discloses a generator stator foot load adjustment test method based on vibration control, and the method comprises the steps: obtaining the shaft vibration and bearing vibration data of a front bearing and a rear bearing, and judging whether a supporting system has a structure resonance phenomenon or not; measuring bottom foot vibration data, and judging whether a structure resonance phenomenon caused by unreasonable stator bottom foot load distribution possibly exists or not; performing an overspeed test on the unit, and performing a stator bottom load adjustment test and judging a frequency modulation direction if a formant exists and a working rotating speed avoidance frequency margin meets a judgment condition; performing a modal test on the stator during shutdown to obtain cold-state initial modal frequency data, correcting the cold-state initial modal frequency data with the hot-state modal frequency data, and verifying the frequency modulation direction; performing a stator foot load uniform distribution adjustment test and modal test verification, and if a modal frequency avoidance degree requirement is met, ending the test; otherwise, performing a stator foot load fine adjustment test, calculating to obtain elevation fine adjustment data of each area of the stator foot meeting conditions according to the influence coefficient, and ending the test.

Description

Technical Field

[0001] The invention relates to the technical field of power machinery engineering, and in particular to a generator stator foot load adjustment test method based on vibration control. Background Art

[0002] The generator support bearings of large steam turbine generator sets (300MW capacity and above) are mostly designed as end cover bearings, that is, the bearings are seated on the generator stator end cover, and the support system is composed of multiple units such as bearing-stator-foot-plate-foundation. The dynamic stiffness of the support system is coupled by the structural dynamic stiffness and connection dynamic stiffness of the above units. Among them, the structural dynamic stiffness is related to the design factors, and the connection dynamic stiffness is mainly related to the installation factors. Since the end cover bearing itself has weak structural dynamic stiffness, the support system stiffness is more sensitive to the change of connection dynamic stiffness (that is, the change of installation parameters). When the installation parameters deviate from the appropriate value, the dynamic stiffness of the support system decreases significantly, causing the generator stator structure resonance at the working speed, resulting in large bearing vibration, which seriously threatens the safe operation of the unit. The field of on-site fault diagnosis and prevention urgently needs to form an effective generator stator foot load fine adjustment test method.

[0003] There are several existing methods for treating generator structural resonance failures: 1) During the operation of the unit, the mass of the vibration system is changed by pressing sandbags or damping-mass particles to adjust the frequency, but the mass of the generator stator is large (up to hundreds of tons), and light weights cannot achieve the frequency adjustment effect. Heavy weights will cause local deformation of the generator and cause other risks; 2) Perform fine dynamic balancing tests on the generator rotor, but since the main cause of the failure is structural resonance, the shaft amplitude is very small, dynamic balancing is difficult, and the effect is not uniform; 3) Perform a load distribution test on the generator stator foot. The current load distribution test method is to evenly distribute the load to each area of ​​the generator foot according to the relevant load distribution standards given by the manufacturer. The distribution standard only gives a wider load range, and does not make adaptive adjustments based on the actual vibration conditions and structural modal frequencies of the unit. Therefore, this method has limitations and blindness, and the results obtained after implementation vary from unit to unit. In summary, there is currently a lack of effective and systematic methods for treating generator structural resonance. Summary of the invention

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

[0005] The purpose of the present invention is to overcome the shortcomings and limitations of the above-mentioned prior art, and to provide a generator stator foot load adjustment test method based on vibration control, which combines the unit vibration data, modal data and actual maintenance process to adjust the generator stator modal frequency, improve the working speed structural resonance phenomenon, and effectively control the unit vibration level.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In the first aspect, the present invention provides a generator stator foot load adjustment test method based on vibration control, including: obtaining the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is a structural resonance phenomenon in the generator support system; measuring the generator foot vibration data to preliminarily determine whether there is a structural resonance phenomenon in the support system caused by unreasonable stator foot load distribution; performing an overspeed test on the unit, obtaining the bearing vibration data during the speed change process for spectrum analysis and finding the resonance peak. If the resonance peak exists and the frequency margin with the working speed meets the judgment condition, it is necessary to perform a stator foot load adjustment test and preliminarily determine the frequency modulation direction; shut down for maintenance During the test, a modal test is performed on the generator stator to obtain cold initial modal frequency data, and the cold initial modal frequency data is compared and corrected with the hot modal frequency data to verify the frequency modulation direction; a uniform distribution adjustment test of the generator stator foot load is performed according to conventional load distribution standards, and a modal test verification is performed. If the modal frequency avoidance requirements are met, the test is terminated; if the modal frequency avoidance requirements are not met, a fine adjustment test of the generator stator foot load is performed to obtain the elevation-modal frequency influence coefficient of each foot area, and the fine adjustment data of the stator foot elevation that meets the conditions is calculated based on the influence coefficient, and the test is terminated.

[0008] As a preferred solution of the generator stator foot load adjustment test method based on vibration control described in the present invention, the determination of whether the generator support system has structural resonance includes:

[0009] Obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator during the operation of the unit, and define the dynamic stiffness evaluation factor of the support system as the ratio of the shaft amplitude value to the bearing bearing amplitude value;

[0010] If the amplitude value of a certain bearing pad is greater than the first threshold value and the dynamic stiffness evaluation factor of the support system is less than the second threshold value, it is considered that the generator stator support system may have structural resonance, otherwise there is no need to perform the stator foot load adjustment test.

[0011] As a preferred solution of the generator stator foot load adjustment test method based on vibration control described in the present invention, the determination of whether there may be a structural resonance phenomenon of the support system caused by unreasonable stator foot load distribution includes:

[0012] Measure the vibration data of each measuring point on the generator foot and find the maximum amplitude;

[0013] If the maximum amplitude is greater than the third threshold, it is considered that the support system may have structural resonance caused by unreasonable stator foot load distribution, otherwise there is no need to perform a stator foot load adjustment test.

[0014] As a preferred solution of the generator stator foot load adjustment test method based on vibration control described in the present invention, the process of determining whether to perform the stator foot load adjustment test and preliminarily determine the frequency modulation direction includes:

[0015] Conduct overspeed test on the unit, obtain bearing vibration data during speed change, perform spectrum analysis, draw Bode diagram of bearing vibration one-fold frequency component and find resonance peak;

[0016] The frequency optimization direction target is defined as the resonance speed and the rated speed avoiding frequency margin are both greater than the fourth threshold;

[0017] If the bearing vibration resonance peak exists and the frequency margin from the operating speed meets the judgment conditions, it is considered necessary to carry out the stator foot load adjustment test, and at the same time, the frequency adjustment direction should be determined according to the frequency adjustment principle. Otherwise, there is no need to carry out the stator foot load adjustment test.

[0018] As a preferred solution of the generator stator foot load adjustment test method based on vibration control according to the present invention, the comparison and correction process includes:

[0019] During the shutdown and maintenance period, the generator stator is subjected to modal test to obtain the cold modal frequency distribution of the generator stator and extract the first n-order cold modal frequency data;

[0020] The cold state modal frequency data is compared and corrected with the frequency corresponding to the resonance peak in the Bode diagram to obtain the correction coefficient Δ of each order modal frequency of the cold state and the hot state n , and verify the frequency adjustment direction, wherein the frequency corresponding to the resonance peak in the Bode diagram is the thermal mode frequency.

[0021] As a preferred solution of the generator stator foot load adjustment test method based on vibration control described in the present invention, the generator stator foot load uniform distribution adjustment test includes:

[0022] Divide the four bases of the generator in sequence from the end to the inside;

[0023] According to the load standard specified by the manufacturer, the loads in different areas of each foot are adjusted evenly in proportion by adding or removing gaskets between the generator foot and the platform;

[0024] Under this condition, the generator stator is subjected to modal test, and the first n cold modal frequency data are extracted and recorded as f 1 、f 2 ,……,f n , if both have |f n -Δ n -50|>2.5, that is, the modal frequency avoidance requirement is met, and the test ends.

[0025] As a preferred solution of the generator stator foot load adjustment test method based on vibration control described in the present invention, the generator stator foot load fine adjustment test comprises:

[0026] If the modal frequency avoidance requirement is not met after the stator foot load uniform distribution test, a fine adjustment test of the generator stator foot load is carried out, and the stator foot area A, area B, area C, and area D are raised h mm in turn, and the stator cold modal frequency is measured respectively to obtain the adjustment influence coefficient of the corresponding area elevation adjustment and the cold modal frequency response;

[0027] Define the elevation-modal frequency influence coefficient matrix α, the initial hot stator modal frequency matrix f, and the shim adjustment thickness matrix H for each area of ​​the foot;

[0028] Calculate the adjusted hot stator modal frequency matrix P, the formula is: P = α·H + f;

[0029] For different areas of the stator foot, the shim adjustment thickness should meet the following conditions, namely: the shim thickness h of each area A 、h B 、h C 、h D , satisfying |h A |+|h B |+|h C |+|h D |<0.20, and for any P(i,j)∈p, |p(i,j)-50|>2.5;

[0030] The fine adjustment data of the elevation of each area of ​​the stator foot that meets the conditions is obtained based on the influence coefficient calculation, and modal test verification is carried out to complete the fine adjustment test of the stator foot load.

[0031] In a second aspect, the present invention provides a generator stator foot load adjustment test system based on vibration control, comprising:

[0032] The first judgment module is used to obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is structural resonance in the generator support system;

[0033] The second judgment module is used to measure the vibration data of the generator foot to preliminarily judge whether there is a structural resonance phenomenon of the support system caused by unreasonable load distribution of the stator foot;

[0034] The third judgment module is used to perform an overspeed test on the unit, obtain the bearing vibration data during the speed change process, perform spectrum analysis and find the resonance peak. If the resonance peak exists and the frequency margin with the working speed meets the judgment condition, it is necessary to perform a stator foot load adjustment test and preliminarily judge the frequency modulation direction;

[0035] The cold and hot modal frequency correction module is used to perform a modal test on the generator stator during shutdown and maintenance to obtain cold initial modal frequency data, compare and correct the cold initial modal frequency data with the hot modal frequency data, and verify the frequency modulation direction;

[0036] The foot load uniform distribution adjustment and verification module is used to perform a generator stator foot load uniform distribution adjustment test according to conventional load distribution standards and perform a modal test verification. If the modal frequency avoidance requirements are met, the test ends;

[0037] The foot load fine adjustment module is used to conduct a generator stator foot load fine adjustment test if the modal frequency avoidance requirement is not met, obtain the elevation-modal frequency influence coefficient of each foot area, and calculate the fine adjustment data of the stator foot elevation of each area that meets the conditions based on the influence coefficient, and the test ends.

[0038] In a third aspect, the present invention provides an electronic device, comprising:

[0039] Memory and processor;

[0040] 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 generator stator foot load adjustment test method based on vibration control are implemented.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the generator stator foot load adjustment test method based on vibration control.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a test method for adjusting the stator foot load of a generator based on vibration control. In specific operations, the method obtains the relevant vibration data of the operation process for feature analysis, and combines the modal test data as a guide to formulate a fine adjustment plan for the stator foot load of the generator during maintenance, which provides a scientific basis for solving existing faults and preventing faults from occurring, and provides guidance for maintenance personnel to formulate maintenance plans in advance and improve the maintenance process level. The method has high accuracy and real-time performance. At the same time, the vibration data required by the present invention can directly use the TDM system data that is randomly equipped with the steam turbine generator set, and cooperate with a simple handheld vibration meter and modal analyzer. The operating conditions are simple, it is easy to implement on site, and the plan is reliable. It has successfully solved the resonance fault of the generator stator structure in on-site fault diagnosis and treatment many times, ensuring the safety of the equipment while also creating huge economic and social benefits for the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0044] Figure 1 It is a schematic diagram of the overall process logic of a generator stator foot load adjustment test method based on vibration control according to an embodiment of the present invention;

[0045] Figure 2 A flow chart of a generator stator foot load adjustment test method based on vibration control according to an embodiment of the present invention;

[0046] Figure 3 A schematic diagram of a generator stator according to a generator stator foot load adjustment test method based on vibration control according to an embodiment of the present invention;

[0047] Figure 4 A schematic diagram of an on-site measurement position of a generator stator foot load adjustment test method based on vibration control according to an embodiment of the present invention;

[0048] Figure 5 A Bode diagram of a generator vibration during an overspeed test of a generator stator foot load adjustment test method based on vibration control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0050] Example 1

[0051] Reference Figure 1-Figure 3 As one embodiment of the present invention, a test method for adjusting the stator foot load of a generator based on vibration control is provided, such as Figure 1 The specific steps shown include:

[0052] S100: Acquire the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is structural resonance in the generator support system;

[0053] S200: Measure the vibration data of the generator foot to preliminarily determine whether there is structural resonance of the support system caused by unreasonable load distribution on the stator foot;

[0054] S300: Perform an overspeed test on the unit, obtain the bearing vibration data during the speed change process, perform spectrum analysis and find the resonance peak. If there is a resonance peak and the frequency margin with the operating speed meets the judgment conditions, it is necessary to perform a stator foot load adjustment test and preliminarily determine the frequency modulation direction;

[0055] S400: During the shutdown and maintenance period, a modal test is performed on the generator stator to obtain the cold initial modal frequency data, and the cold initial modal frequency data is compared and corrected with the hot modal frequency data to verify the frequency modulation direction;

[0056] S500: Perform a uniform distribution adjustment test on the stator foot load of the generator according to the conventional load distribution standard, and perform a modal test verification. If the modal frequency avoidance requirement is met, the test ends;

[0057] S600: If the modal frequency avoidance requirement is not met, a fine adjustment test of the generator stator foot load is performed to obtain the elevation-modal frequency influence coefficient of each foot area, and the fine adjustment data of the stator foot elevation of each area that meets the conditions is calculated based on the influence coefficient, and the test ends.

[0058] It should be noted that the present invention provides a test method for adjusting the stator foot load of a generator based on vibration control. In the specific operation, the relevant vibration data of the operation process is obtained for feature analysis, and the modal test data is used as a guide to formulate a fine adjustment plan for the stator foot load of the generator during maintenance, so as to provide a scientific basis for solving existing faults and preventing faults from occurring, and provide guidance for maintenance personnel to formulate maintenance plans in advance and improve the maintenance process level, with high accuracy and real-time performance. At the same time, the vibration data required by the present invention can directly use the TDM system data randomly equipped with the steam turbine generator set, and cooperate with a simple handheld vibration meter and a modal analyzer. The operating conditions are simple, it is easy to implement on site, and the plan is reliable. It has successfully solved the resonance fault of the generator stator structure in on-site fault diagnosis and treatment many times, ensuring the safety of the equipment while also creating huge economic and social benefits for the power plant.

[0059] In an embodiment of the present application, the above-mentioned step S100 includes: obtaining the shaft vibration and bearing vibration data of the front and rear bearings of the generator; if the amplitude value of a certain bearing bearing is greater than the first threshold value and the dynamic stiffness evaluation factor of the support system is less than the second threshold value, it is considered that the stator support system of the generator may have structural resonance, otherwise there is no need to perform a stator foot load adjustment test.

[0060] Specifically, the first threshold is 50 μm, and the second threshold is 1;

[0061] Specifically, Figure 2 As shown, the shaft vibration data As and bearing vibration data Ab of the front and rear bearings of the generator during the operation of the unit are obtained, and the dynamic stiffness evaluation factor Cb of the support system is defined as the ratio of the shaft amplitude value As to the bearing bearing amplitude value Ab, that is, Cb = As / Ab; ​​if the amplitude value Ab of a certain bearing bearing is greater than 50μm, and the dynamic stiffness evaluation factor Cb of the bearing support system is less than 1, it is preliminarily believed that the generator stator support system may have structural resonance, otherwise there is no need to perform the stator foot load adjustment test.

[0062] It should be noted that the above step S100 can directly and effectively identify whether there is structural resonance in the support system by obtaining the shaft vibration and bearing vibration data of the front and rear bearings of the generator, which helps to prevent potential failures, reduce unplanned downtime, and provide key basis for subsequent precise adjustments.

[0063] In the embodiment of the present application, the above-mentioned step S200 includes: measuring the vibration data of each measuring point of the generator foot and finding the maximum amplitude; if the maximum amplitude is greater than the third threshold, it is considered that the support system may have structural resonance caused by unreasonable stator foot load distribution, otherwise there is no need to perform a stator foot load adjustment test.

[0064] Specifically, the third threshold is 25 μm;

[0065] Specifically, Figure 2 As shown, the vibration data of each measuring point of the generator foot is measured, and the maximum amplitude is found and recorded as Af; if Af>25μm, it is considered that the support system may have structural resonance caused by unreasonable stator foot load distribution, otherwise there is no need to perform stator foot load adjustment test.

[0066] It should be noted that the above step S200 can preliminarily determine whether the load distribution of the stator foot is reasonable by measuring the vibration data of the generator foot, thereby effectively identifying and preventing structural resonance problems caused by uneven load and ensuring the stability and safety of the support system.

[0067] In an embodiment of the present application, the above-mentioned step S300 includes: finding a suitable start-up and shutdown opportunity, performing an overspeed test on the unit, obtaining the bearing vibration data during the speed change process for spectral analysis, drawing a Bode diagram of the first-harmonic component of the bearing vibration and finding the bearing vibration resonance peak. If there is a bearing vibration resonance peak, and the frequency avoidance margin with the operating speed meets the judgment condition, that is, the frequency avoidance margin with the operating speed is less than the fourth threshold, it is considered that a stator foot load adjustment test is required, and the frequency adjustment direction is preliminarily determined: the resonant speed and the rated speed avoidance frequency margin are both greater than the fourth threshold, otherwise there is no need to perform a stator foot load adjustment test.

[0068] Specifically, the fourth threshold is 2.5 Hz;

[0069] like Figure 2 The specific steps shown are:

[0070] Find a suitable start-stop opportunity for the unit and conduct a 110% overspeed test, that is, the speed is increased to 110% of the rated speed (for a unit with a rated speed of 3000rpm, it is increased to 3300rpm), and obtain bearing vibration data during the speed change process;

[0071] Perform spectrum analysis on bearing vibration data during speed change and draw Bode diagram of bearing vibration frequency component.

[0072] Find a certain speed in the Bode diagram. In the range of ±100rpm, the vibration amplitude of this speed is the largest. In the range of ±100rpm, the phase increases and the change amplitude is greater than 60°. Define this speed as the resonant speed and the corresponding vibration as the resonance peak.

[0073] According to the above definition, find the resonance peak of the bearing vibration in the Bode diagram and arrange them from low to high according to the rotation speed, which are recorded as Abs 1 , Abs 2、 ..., Abs n , and the corresponding speed is recorded as Rbs 1 , Rbs 2 ,……,Rbs n(Based on a large number of field test data, n≤4);

[0074] The frequency optimization direction goal is defined as: the frequency margin of the resonant speed and the rated speed is greater than 2.5Hz;

[0075] If the bearing vibration resonance peak exists and the frequency margin from the operating speed is less than 2.5Hz, it is considered necessary to conduct a stator foot load fine adjustment test. At the same time, based on the frequency adjustment principle, the frequency optimization direction should be preliminarily determined. Otherwise, there is no need to conduct a stator foot load adjustment test.

[0076] It should be noted that the above step S300 can accurately find the resonance peak by conducting an overspeed test on the unit and analyzing the bearing vibration data during the speed change process, and can timely discover and adjust possible resonance problems, clarify whether a stator foot load adjustment test is needed, ensure the safety and stability of the unit operation, and provide a scientific basis for the subsequent frequency regulation direction.

[0077] In the embodiment of the present application, the above step S400 includes: performing a modal test on the generator stator during the shutdown and maintenance period, obtaining the cold modal frequency data of the stator for the first few orders, comparing and correcting the cold modal frequency data with the frequency corresponding to the resonance peak in the Bode diagram, and obtaining the correction coefficient Δ of each order of the cold and hot modal frequency. n , and verify the frequency adjustment direction, where the frequency corresponding to the resonance peak in the Bode diagram is the thermal mode frequency.

[0078] The specific steps are:

[0079] After the shutdown standby unit reaches a cold state, a modal test is performed on the generator stator;

[0080] Obtain the cold modal frequency distribution of the generator stator and extract the first n modal frequency data, which are recorded as f 01 、f 02 ,……,f 0n ;

[0081] The frequency data (i.e., cold modal frequency) obtained from the modal test is f 0n The frequency corresponding to the resonance peak in the Bode diagram (i.e., thermal mode frequency) Rbs n / 60 for comparison and correction, and obtain the correction coefficients Δ of each order modal frequency in cold and hot states 1 =f 01 -Rbs 1 / 60,Δ 2 =f 02 -Rbs 2 / 60, ..., Δ n =f 0n -Rbs n / 60, and verify the modal test frequency adjustment direction.

[0082] In the embodiment of the present application, the above step S500 includes: distributing the loads evenly in the same area of ​​the four ends of the stator foot of the generator according to the load distribution standard given by the manufacturer, performing a stator modal test under this working condition, re-measuring the modal frequency, and ending the test if the modal frequency avoidance requirement is met;

[0083] The specific steps are:

[0084] like Figure 3 As shown, the four bases of the generator are divided into A 1 , B 1 , C 1 , D 1 , A 2 , B 2 , C 2 , D 2 , A 3 , B 3 , C 3 , D 3 , A 4 , B 4 , C 4 , D 4 Four areas, four of which are foot A 1 ~A 4 The regional loads are denoted as L A1 , L A2 , L A3 , L A4 , and similarly, place the four bases B 1 ~B 4 , C 1 ~C 4 , D 1 ~D 4 The regional loads are denoted as L B1 , L B2 , L B3 , L B4 , L C1 , L C2 , L C3 , L C4 , L D1 , L D2 , L D3 , L D4 ;

[0085] According to the load standard specified by the manufacturer, the loads in different areas of each foot are adjusted proportionally by adding or removing gaskets between the generator foot and the platform, that is, for the four foot, L A1 , L A2 , L A3 , L A4 The difference between any two of them is denoted as ΔLA ,satisfy in Same reason in addition,

[0086] Under this condition, the generator stator is subjected to modal test, and the first n-order cold modal frequency data are extracted and recorded as f 1 、f 2 ,……,f n , if both have |f n -Δ n -50|>2.5, the test ends.

[0087] In the embodiment of the present application, the above-mentioned step S600 includes: if the modal frequency avoidance requirement is not met after the stator foot load uniform distribution test, a fine adjustment test of the generator stator foot load is performed, and the stator foot area A, area B, area C, and area D are raised h mm in turn, and the stator cold modal frequency is measured respectively to obtain the influence coefficient of the elevation adjustment of the area and the cold modal frequency response, and the adjusted thickness of the gasket in each area of ​​the foot that meets the conditions is calculated based on this, and a modal test verification is performed to complete the stator foot load fine adjustment test.

[0088] The specific steps are:

[0089] The foot A area (A 1 , A 2 , A 3 , A 4 ) The thickness of the gasket is raised by h mm synchronously, while the thickness of the gasket in other areas remains unchanged; under this condition, the modal test is carried out on the generator stator, and the first n-order cold modal frequency data are extracted, which are recorded as f 1A 、f 2A ,……,f nA ; Define the footing A area (A 1 , A 2 , A 3 , A 4 ) The adjusted impact coefficient is:

[0090]

[0091] After the modal test is completed, the gasket in area A is removed, and then the gasket in area B (B 1 , B 2 , B 3 , B 4 ) The thickness of the gasket is raised by h mm synchronously, while the thickness of the gasket in other areas remains unchanged; under this condition, the modal test is carried out on the generator stator, and the first n-order cold modal frequency data are extracted, which are recorded as f1B 、f 2B ,……,f nB ; Define the footing B area (B 1 , B 2 , B 3 , B 4 ) The adjusted impact coefficient is:

[0092]

[0093] After the modal test is completed, the gasket in area B is removed, and then the gasket in area C of the foot (C 1 , C 2 , C 3 , C 4 ) The thickness of the gasket is raised synchronously by h mm, while the thickness of the gasket in other areas remains unchanged; repeat the above steps to obtain the elevation-modal frequency influence coefficient α of the footing area C and area D in turn 1C , α 2C ,……,α nC , α 1D , α 2D ,……,α nD ;

[0094] Define the elevation-modal frequency influence coefficient matrix α;

[0095]

[0096] Define the initial hot stator modal frequency matrix f:

[0097]

[0098] Define the thickness matrix H of the pads in each area of ​​the foot:

[0099]

[0100] Calculate the adjusted hot stator modal frequency matrix P:

[0101] P=α·H+f

[0102] For different areas of the stator foot, the shim adjustment thickness should meet the following conditions, namely: shim thickness h A 、h B 、h C 、h D , satisfying |h A |+|h B |+|h C |+|h D|<0.20, and any P(i,j)∈P has |P(i,j)-50|>2.5, then it is considered that the adjusted stator modal frequency and operating speed have sufficient avoidance margin, which can effectively improve the generator stator structure resonance fault and perform modal frequency verification. So far, the stator foot load fine adjustment test is completed.

[0103] It should be noted that the above steps S400 to S600 can accurately adjust the stator foot load distribution by performing modal tests on the generator stator during shutdown and maintenance, and ensure that the modal frequency avoids the resonance area, thereby effectively preventing structural resonance failures and ensuring long-term stable operation of the equipment based on the comparison and correction of the cold and hot state modal frequency data.

[0104] Example 2

[0105] Reference Figure 4 and Figure 5 Based on the previous embodiment, this embodiment provides an application example of a generator stator foot load adjustment test method based on vibration control. Taking a 660MW unit generator in a power plant as an example, the whole process of applying this method to conduct a generator stator foot load fine adjustment test is introduced in detail to illustrate the effectiveness and practicality of the method provided by this embodiment.

[0106] The vibration data of the front and rear bearings of the generator during operation are obtained, as shown in Table 1. It can be solved that the dynamic stiffness evaluation factor of bearing No. 7 is Cb=0.56<1, the dynamic stiffness evaluation factor of bearing No. 8 is Cb=0.88<1, and the bearing vibration is greater than 50μm. It is believed that the stator support system of the generator may have structural resonance.

[0107] Table 1: Generator vibration data during operation (through frequency, μm);

[0108]

[0109] Furthermore, the vibration of the generator foot is measured, such as Figure 4 The figure shows the schematic diagram of the on-site measurement position. The vibration data are shown in Table 2. It can be seen that the maximum vibration of the stator foot is 37μm. It is believed that the support system may have structural resonance caused by unreasonable load distribution on the stator foot.

[0110] Table 2: Generator stator external characteristic vibration data (through frequency, μm);

[0111]

[0112] Figure 3The Bode plot of the vibration during the overspeed test is given. It can be seen that there are three resonance peaks in the Bode curve. The frequency optimization direction is to adjust the stator foot load to make the resonance peak 3 as far away from the rated speed (3000rpm) as possible. Then the generator stator modal test is carried out to obtain the first three modes and calculate the cold and hot modal frequency correction values, as shown in Table 3.

[0113] Table 3: Generator stator modal frequency correction data (frequency, Hz);

[0114]

[0115]

[0116] After the generator stator foot load uniform distribution test was carried out, the modal verification test was carried out again. As shown in Table 4, it can be seen that the third-order modal frequency avoidance margin is only 1.1Hz<2.5Hz, so the generator stator foot load fine adjustment test is required.

[0117] Table 4: Generator stator modal frequency data (frequency, Hz);

[0118]

[0119] A 1 ~A 4 , B 1 ~B 4 , C 1 ~C 4 , D 1 ~D 4 The regional elevation is raised by 0.10 mm, and the elevation-modal frequency influence coefficient matrix α is calculated:

[0120]

[0121] The fine adjustment thickness of the gasket that meets the conditions is obtained: A 1 ~A 4 Adjust 0mm, B 1 ~B 4 Both are reduced by 0.02mm, C 1 ~C 4 Both are reduced by 0.02mm, D 1 ~D 4 All are reduced by 0.01mm, satisfying |h A |+|h B |+|h C |+|h D|<0.20, and for any P(i, j)∈P, |P(i, j)-50|>2.5; the re-measured cold stator modal frequency is shown in Table 5. It can be seen that the measured stator modal frequency of the generator after adjustment is basically consistent with the calculated data, and the margin from the rated speed meets the operation requirements.

[0122] Table 5: Repeatedly measured generator stator modal frequency data (frequency, Hz);

[0123]

[0124] After the unit was started up and running, the vibration of the generator bearing was within 30μm, which was in an excellent range and was greatly improved compared to before the repair.

[0125] It can be seen from the above application examples that the generator stator foot load adjustment test method based on vibration control provided by the present invention performs characteristic analysis by acquiring relevant vibration data of the operation process during specific operation, and combines modal test data as a guide to formulate a fine adjustment plan for the generator stator foot load during maintenance, which provides a scientific basis for solving existing faults and preventing faults from occurring, and provides guidance for maintenance personnel to formulate maintenance plans in advance and improve the maintenance process level, with high accuracy and real-time performance. At the same time, the vibration data required by the present invention can directly use the TDM system data randomly equipped with the steam turbine generator set, in conjunction with a simple handheld vibration meter and modal analyzer, the operating conditions are simple, it is easy to implement on site, and the plan is reliable. It has successfully solved the resonance fault of the generator stator structure in on-site fault diagnosis and management many times, ensuring the safety of the equipment while also creating huge economic and social benefits for the power plant.

[0126] Example 3

[0127] This embodiment provides a generator stator foot load adjustment test system based on vibration control, including:

[0128] The first judgment module is used to obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is structural resonance in the generator support system;

[0129] The second judgment module is used to measure the vibration data of the generator foot to preliminarily judge whether there is a structural resonance phenomenon of the support system caused by unreasonable load distribution of the stator foot;

[0130] The third judgment module is used to perform an overspeed test on the unit, obtain the bearing vibration data during the speed change process, perform spectrum analysis and find the resonance peak. If there is a resonance peak and the frequency margin with the working speed meets the judgment conditions, it is necessary to perform a stator foot load adjustment test and preliminarily determine the frequency modulation direction;

[0131] The cold and hot modal frequency correction module is used to perform modal tests on the generator stator during shutdown and maintenance to obtain the cold initial modal frequency data, compare and correct the cold initial modal frequency data with the hot modal frequency data, and verify the frequency modulation direction;

[0132] The foot load uniform distribution adjustment and verification module is used to perform a generator stator foot load uniform distribution adjustment test according to conventional load distribution standards and perform a modal test verification. If the modal frequency avoidance requirements are met, the test ends;

[0133] The foot load fine adjustment module is used to conduct a generator stator foot load fine adjustment test if the modal frequency avoidance requirement is not met, obtain the elevation-modal frequency influence coefficient of each foot area, and calculate the fine adjustment data of the stator foot elevation of each area that meets the conditions based on the influence coefficient, and the test ends.

[0134] It should be noted that the technical solution of the system for testing the stator base load adjustment of the generator based on vibration control and the technical solution of the method for testing the stator base load adjustment of the generator based on vibration control belong to the same concept. For the details not described in detail in the technical solution of the system for testing the stator base load adjustment of the generator based on vibration control in this embodiment, please refer to the description of the technical solution of the method for testing the stator base load adjustment of the generator based on vibration control.

[0135] The above-mentioned unit modules may be embedded in or independent of a processor in a computer device in the form of hardware, or may be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to the above-mentioned modules.

[0136] 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 implemented through WIFI, an operator network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a generator stator foot load adjustment test method based on vibration control is implemented. 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, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse.

[0137] This embodiment also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method proposed in the above embodiment is implemented.

[0138] 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 fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0139] Through the above description of the implementation mode, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course it can also be implemented by hardware, but in many cases the former is a better implementation mode. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the method of the embodiment of the present invention.

[0140] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0141] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the application can adopt 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.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages.

[0142] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0143] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0144] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0145] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0146] 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 equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A test method for adjusting the stator foot load of a generator based on vibration control, characterized in that: include: Obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is structural resonance in the generator support system; Measure the vibration data of the generator foot to preliminarily determine whether there is structural resonance of the support system caused by unreasonable load distribution of the stator foot; Perform an overspeed test on the unit, obtain the bearing vibration data during the speed change process, perform spectrum analysis and find the resonance peak. If the resonance peak exists and the frequency margin with the operating speed meets the judgment conditions, it is necessary to perform a stator foot load adjustment test and preliminarily determine the frequency modulation direction; During the shutdown and overhaul period, a modal test is performed on the generator stator to obtain cold initial modal frequency data, and the cold initial modal frequency data is compared and corrected with the hot modal frequency data to verify the frequency modulation direction; According to the conventional load distribution standard, the generator stator foot load uniform distribution adjustment test is carried out, and the modal test verification is carried out. If the modal frequency avoidance requirements are met, the test is terminated; If the modal frequency avoidance requirement is not met, a fine adjustment test of the generator stator foot load is carried out to obtain the elevation-modal frequency influence coefficient of each foot area. The fine adjustment data of the stator foot elevation of each area that meets the conditions is calculated based on the influence coefficient, and the test is terminated.

2. The generator stator foot load adjustment test method based on vibration control according to claim 1, characterized in that: The determining whether the generator support system has structural resonance phenomenon comprises: Obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator during the operation of the unit, and define the dynamic stiffness evaluation factor of the support system as the ratio of the shaft amplitude value to the bearing bearing amplitude value; If the amplitude value of a certain bearing pad is greater than the first threshold value and the dynamic stiffness evaluation factor of the support system is less than the second threshold value, it is considered that the generator stator support system may have structural resonance, otherwise there is no need to perform the stator foot load adjustment test.

3. The generator stator foot load adjustment test method based on vibration control according to claim 2, characterized in that: Judging whether there may be structural resonance of the support system caused by unreasonable load distribution of the stator foot includes: Measure the vibration data of each measuring point on the generator foot and find the maximum amplitude; If the maximum amplitude is greater than the third threshold, it is considered that the support system may have structural resonance caused by unreasonable stator foot load distribution, otherwise there is no need to perform a stator foot load adjustment test.

4. The generator stator foot load adjustment test method based on vibration control according to claim 3, characterized in that: The process of determining whether a stator foot load adjustment test is required and preliminarily determining the frequency modulation direction includes: Conduct overspeed test on the unit, obtain bearing vibration data during speed change, perform spectrum analysis, draw Bode diagram of bearing vibration one-fold frequency component and find resonance peak; The frequency optimization direction target is defined as the resonance speed and the rated speed avoiding frequency margin are both greater than the fourth threshold; If the bearing vibration resonance peak exists and the frequency margin from the operating speed meets the judgment conditions, it is considered necessary to carry out the stator foot load adjustment test, and at the same time, the frequency adjustment direction should be determined according to the frequency adjustment principle. Otherwise, there is no need to carry out the stator foot load adjustment test.

5. The generator stator foot load adjustment test method based on vibration control according to claim 4, characterized in that: The process of comparison and correction includes: During the shutdown and maintenance period, the generator stator is subjected to modal test to obtain the cold modal frequency distribution of the generator stator and extract the first n-order cold modal frequency data; The cold state modal frequency data is compared and corrected with the frequency corresponding to the resonance peak in the Bode diagram to obtain the correction coefficient Δ of each order modal frequency of the cold state and the hot state n , and verify the frequency adjustment direction, wherein the frequency corresponding to the resonance peak in the Bode diagram is the thermal mode frequency.

6. The generator stator foot load adjustment test method based on vibration control according to claim 5, characterized in that: The generator stator foot load uniform distribution adjustment test comprises: Divide the four bases of the generator in sequence from the end to the inside; According to the load standard specified by the manufacturer, the loads in different areas of each foot are adjusted evenly in proportion by adding or removing gaskets between the generator foot and the platform; Under this condition, the generator stator is subjected to modal test, and the first n cold modal frequency data are extracted and recorded as f1, f2, ..., f n , if both have |f n -Δ n -50|>2.5, that is, the modal frequency avoidance requirement is met, and the test ends.

7. The generator stator foot load adjustment test method based on vibration control according to claim 6, characterized in that: The generator stator foot load fine adjustment test comprises: If the modal frequency avoidance requirement is not met after the stator foot load uniform distribution test, a fine adjustment test of the generator stator foot load is carried out, and the stator foot area A, area B, area C, and area D are raised h mm in turn, and the stator cold modal frequency is measured respectively to obtain the adjustment influence coefficient of the corresponding area elevation adjustment and the cold modal frequency response; Define the elevation-modal frequency influence coefficient matrix α, the initial hot stator modal frequency matrix f, and the shim adjustment thickness matrix H for each area of ​​the foot; Calculate the adjusted hot stator modal frequency matrix P, the formula is: P = α·H + f; For different areas of the stator foot, the shim adjustment thickness should meet the following conditions, namely: the shim thickness h of each area A 、h B 、h C 、h D , satisfying |h A |+|h B |+|h C |+|h D |<0.20, and for any P(i,j)∈p, |p(i,j)-50|>2.5; The fine adjustment data of the elevation of each area of ​​the stator foot that meets the conditions is obtained based on the influence coefficient calculation, and modal test verification is carried out to complete the fine adjustment test of the stator foot load.

8. A system using the generator stator foot load adjustment test method based on vibration control as claimed in any one of claims 1 to 7, characterized in that: include: The first judgment module is used to obtain the shaft vibration and bearing vibration data of the front and rear bearings of the generator to determine whether there is structural resonance in the generator support system; The second judgment module is used to measure the vibration data of the generator foot to preliminarily judge whether there is a structural resonance phenomenon of the support system caused by unreasonable load distribution of the stator foot; The third judgment module is used to perform an overspeed test on the unit, obtain the bearing vibration data during the speed change process, perform spectrum analysis and find the resonance peak. If the resonance peak exists and the frequency margin with the working speed meets the judgment condition, it is necessary to perform a stator foot load adjustment test and preliminarily judge the frequency modulation direction; The cold and hot modal frequency correction module is used to perform a modal test on the generator stator during shutdown and maintenance to obtain cold initial modal frequency data, compare and correct the cold initial modal frequency data with the hot modal frequency data, and verify the frequency modulation direction; The foot load uniform distribution adjustment and verification module is used to perform a generator stator foot load uniform distribution adjustment test according to conventional load distribution standards and perform a modal test verification. If the modal frequency avoidance requirements are met, the test ends; The foot load fine adjustment module is used to conduct a generator stator foot load fine adjustment test if the modal frequency avoidance requirement is not met, obtain the elevation-modal frequency influence coefficient of each foot area, and calculate the fine adjustment data of the stator foot elevation of each area that meets the conditions based on the influence coefficient, and the test ends.

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.

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