Method for quickly identifying contact friction and rotating part flying-off faults

Abstract

The invention belongs to the field of power mechanical engineering, and discloses a method for quickly identifying contact friction and rotating part fly-off faults, which comprises the following steps of: obtaining relative shaft vibration data of each measuring point of a steam turbine generator unit through measurement or inquiry, and quickly finding out the measuring point with obvious vibration fluctuation; obtaining relative shaft vibration data of a measuring point with obvious vibration fluctuation, and carrying out necessary spectral analysis on the relative shaft vibration data; according to the vibration data, judging whether the vibration phenomenon accords with the basic characteristics of contact friction and rotating part fly-off faults or not; and according to the vibration characteristics of the contact friction and rotating part flying-off fault, the vibration fault of the unit is identified step by step. According to the invention, whether the unit has a contact friction fault or a rotating part fly-off fault can be rapidly and accurately identified, and effective suggestions and measures are provided for actual production.

Description

Technical Field

[0001] The invention belongs to the field of power mechanical engineering and relates to a method for quickly identifying contact friction and rotating component flying-off faults. Background Art

[0002] Vibration is directly related to the safe and stable operation of steam turbine generator sets. Many faults of steam turbine generator sets can cause abnormal vibration. Different faults have vibration characteristics that are different from other faults, but this difference is sometimes very subtle. Fault diagnosis is to determine the cause of the vibration based on the vibration characteristics and related information. The more accurate the conclusion of fault diagnosis is, the more accurate and targeted the basis can be for the later maintenance and adjustment of steam turbine generator sets.

[0003] Thermal power units are actively carrying out transformation and upgrading, and the three transformations of energy-saving and consumption-reduction transformation, heating transformation and flexibility transformation are continuously promoted to meet the requirements of energy-saving and consumption-reduction and the absorption of new energy. The various energy-saving transformations and flexible operation modes such as rapid start and stop, deep peak regulation implemented by thermal power units have continuously reduced the dynamic and static clearances of steam turbine equipment. At the same time, the operation has also deviated from the original design conditions, resulting in an increase in the frequency of contact friction and vibration failures caused by the flying of rotating parts, which seriously affects the safety and reliability of thermal power units.

[0004] If contact friction and rotating parts flying off faults cannot be accurately and quickly identified, improper operation measures will be taken, causing the risk of unit tripping, and even no guiding suggestions will be provided for the later maintenance and adjustment of the unit. However, the vibrations caused by contact friction and rotating parts flying off faults have similar characteristics and are difficult to identify. Based on this, it is particularly urgent and important to be able to quickly and accurately identify contact friction and rotating parts flying off faults. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a method for quickly identifying contact friction and rotating parts flying off faults. The present invention aims to quickly and accurately identify whether a contact friction fault or a rotating parts flying off fault has occurred in the unit, and provide effective suggested measures for actual production.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for quickly identifying contact friction and rotating parts flying off faults comprises the following steps: When the unit is running, the first measuring point of the bearing has obvious vibration fluctuation phenomenon. If the vibration of the second measuring point of the bearing changes synchronously with the vibration of the first measuring point, it is necessary to continue to judge whether the relative shaft vibration is dominated by the fundamental frequency component before and after the change. Otherwise, it indicates that the unit currently has no contact friction or rotating parts flying off; the second measuring point is the relative shaft vibration measuring point of the first measuring point; When the fundamental frequency component is dominant before and after the relative shaft vibration changes, the duration of the relative shaft vibration change process at the first measuring point is obtained; when the fundamental frequency component is not dominant before and after the relative shaft vibration changes, it indicates that the unit currently has no contact friction or rotating parts flying off; If the duration of the relative shaft vibration change process of the first measuring point is not greater than the preset time, and the unit load is the same and the monitoring section pressure of the unit changes, it indicates that a rotating component of the unit has currently fallen off, and the position of the component falling off is in the area where the monitoring section pressure changes; If the duration of the relative shaft vibration change process of the first measuring point is greater than a preset duration, the amplitude of the shaft vibration change and the unit trip value are used to determine whether contact friction has occurred in the unit.

[0007] Preferably, when the unit is running, the through-frequency and fundamental frequency vibration trend curves are obtained within a period of time before and after the vibration fluctuation of the first measuring point, and data analysis is performed on the through-frequency and fundamental frequency vibration trend curves, and it is determined whether obvious vibration fluctuation occurs at the first measuring point based on the analysis results.

[0008] Preferably, when performing data analysis on the through-frequency and fundamental frequency vibration trend curves, the time T at which the vibration fluctuation of the first measuring point starts is obtained on the through-frequency and fundamental frequency vibration trend curves. 01 And the corresponding vibration V 01 , obtain the vibration value V after the first measuring point moves on the general frequency and fundamental frequency vibration trend curve 11 and time T 11 , set the first measuring point to meet the following conditions: ≥30% Get the second measuring point at T 01 Vibration of the moment 02 and T 11 Vibration of the moment 12 , if the following conditions are met: ≥20% It is determined that the vibration of the second measuring point changes synchronously with the vibration of the first measuring point, otherwise it indicates that no contact friction or flying of rotating parts occurs in the unit.

[0009] Preferably, when judging whether the relative shaft vibration before and after the change is dominated by the fundamental frequency component, the relative shaft vibration data of the first measuring point is subjected to spectrum analysis to obtain the relative shaft vibration data of the first measuring point at T 01 The fundamental frequency vibration V 01bf and T 11 The fundamental frequency vibration V at time 11bf ; If the following conditions are met: ≥70% and ≥70% It is judged that the fundamental frequency component is dominant before and after the relative shaft vibration changes, otherwise it indicates that the fundamental frequency component is not dominant before and after the relative shaft vibration changes.

[0010] Preferably, the frequency of the fundamental frequency component is 50 Hz.

[0011] Preferably, the preset duration is set to 1 minute.

[0012] Preferably, if the duration of the relative shaft vibration change process of the first measuring point is not greater than a preset time length, and the unit load change is not greater than 3MW, it is considered that the unit loads are the same.

[0013] Preferably, the process of judging whether contact friction currently occurs in the unit by using the amplitude of the shaft vibration change and the trip value of the unit includes: If the amplitude of the shaft vibration after the change is less than the over-jump value, keep the current operating parameters of the unit stable, start the unit's top shaft oil pump, and if the relative shaft vibration of the first measuring point drops to the value before the vibration fluctuation, it indicates that the unit is currently experiencing contact friction; otherwise, the contact friction fault is eliminated; If the amplitude of the shaft vibration change is above the trip value and has caused the unit to shut down, use a stethoscope to listen to the sound on site when the speed drops to 500r / min. If an abnormal sound is heard, it indicates that contact friction has occurred in the unit; otherwise, the contact friction fault is eliminated.

[0014] Preferably, the trip value of the unit is 240 μm; When using a stylus to listen on site, listen every time the speed drops by 100r / min until the unit is started. If an abnormal sound is heard, it indicates that contact friction has occurred in the unit; otherwise, the contact friction fault is eliminated.

[0015] Preferably, the angle between the corresponding radii of the first measuring point and the second measuring point distributed on the bearing is 90°.

[0016] The present invention has the following beneficial effects: The method of the present invention triggers a vibration fault identification process when the vibration change at a bearing of the unit exceeds a given limit value; the fault analysis and identification process includes all relative shaft vibration measurement points at the same bearing in the analysis range, fully utilizes the long-term change trend characteristics of the vibration and the spectrum characteristics in the vibration change process, combines a large number of practical case experiences, provides quantitative differentiation indicators for contact friction and rotating parts flying off, and uses the continuity characteristics after the fault occurs to further verify the fault type; the method of the present invention has clear logic, simple steps, and the data used is easy to obtain, and it is highly operable and timely. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the installation position of the relative shaft vibration sensor in Example 1 of the present invention.

[0018] Figure 2 It is a schematic diagram of the installation position of the relative shaft vibration sensor in Example 2 of the present invention.

[0019] Figure 3 A simplified diagram of the shaft system structure of a steam turbine generator set provided in an embodiment of the present invention.

[0020] Figure 4 Trend curve of 1X relative shaft vibration through-frequency and fundamental frequency in the embodiment of the present invention.

[0021] Figure 5 Trend curve of 1Y relative axis vibration through-frequency and fundamental frequency in the embodiment of the present invention.

[0022] Figure 6 1X relative axis vibration waveform spectrum diagram at time T01 when the vibration change starts in the embodiment of the present invention.

[0023] Figure 7 1X relative axis vibration waveform spectrum diagram at time T11 after vibration change in an embodiment of the present invention.

[0024] Figure 8 Trend curve of 1X relative shaft vibration through-frequency and fundamental frequency after starting the top shaft oil pump in the embodiment of the present invention.

[0025] Fig. 9 A simplified diagram of the shaft structure of a steam turbine generator set in an embodiment of the present invention.

[0026] Fig.10 3Y relative axis vibration through-frequency trend curve in the embodiment of the present invention.

[0027] Fig.11 Trend curve of fundamental frequency of 3Y relative axis vibration in the embodiment of the present invention.

[0028] Fig.12 3X relative shaft vibration through-frequency trend curve in the embodiment of the present invention.

[0029] Fig.13 3X relative shaft vibration fundamental frequency trend diagram in an embodiment of the present invention.

[0030] Fig.14 The 3Y relative axis vibration waveform spectrum diagram at time T01 when the vibration change starts in the embodiment of the present invention.

[0031] Fig.15 Spectrum diagram of the 3Y relative axis vibration waveform at time T11 after the vibration changes in the embodiment of the present invention.

[0032] In the figure, 1-bearing. DETAILED DESCRIPTION

[0033] According to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structures and implementations. Therefore, the following specific implementation methods and drawings are only examples of the technical solution of the present invention and should not be regarded as the entirety of the present invention or the limitation of its technical solution.

[0034] The method for quickly identifying contact friction and rotating component flying-off faults of the present invention comprises the following steps: S1, first find the measuring point where the relative shaft vibration of a bearing on the unit (such as a steam turbine generator unit or a thermal power unit) has obvious fluctuations, and record this measuring point as measuring point M1, and then record another relative shaft vibration measuring point of the bearing as measuring point M2; specifically, the definitions of measuring points M1 and M2 are as follows: See Figure 1 and Figure 2 Steam turbine generator sets generally have two relative shaft vibration sensors installed at a certain bearing at a 90° angle. Find the measuring point at a certain bearing where the relative shaft vibration fluctuation is most obvious, and record it as M1. The other relative shaft vibration measuring point at the bearing, that is, the adjacent measuring point, is recorded as M2.

[0035] S2, obtaining the general frequency and fundamental frequency vibration trend curves before and after the vibration fluctuation of the measuring point M1 for a period of time, and performing data analysis on the general frequency and fundamental frequency vibration trend curves. If the vibration of the measuring point M2 also changes synchronously when the measuring point M1 has obvious vibration fluctuation phenomenon, then go to step S3, otherwise, it means that the steam turbine generator set currently has no contact friction or rotating parts flying off; specifically, in this step, the specific operations are as follows: S21, first obtain the general frequency and fundamental frequency vibration trend curves before and after the vibration fluctuation of the measuring point M1, perform data analysis, and find out the time when the vibration fluctuation of the measuring point M1 starts, recorded as T 01 , the corresponding vibration when the vibration fluctuation of measuring point M1 starts is V 01 , find out the vibration value V after the measuring point M1 fluctuates 11 , the time corresponding to the fluctuation of the measuring point M1 is recorded as T 11 , set the measuring point M1 to meet the following conditions: ≥30% S22, find out the measuring point M2 at T 01 Vibration of the moment 02 and in T 11 Vibration of the moment 12 , if the condition is met ≥20%, it is considered that the vibration of the adjacent measuring point M2 has also changed synchronously, and then go to step S3; otherwise, it means that there is no contact friction or flying of rotating parts in the steam turbine generator set.

[0036] S3, perform spectrum analysis on the relative shaft vibration data of the measuring point M1 obtained in step S2, and determine whether the relative shaft vibration is dominated by the fundamental frequency component (50Hz) before and after the change. Generally speaking, when the ratio of the amplitude of the fundamental frequency component to the full-frequency amplitude is greater than 70%, it can be considered that the vibration is dominated by the fundamental frequency, and then go to step S4; otherwise, it means that the steam turbine generator set currently has no contact friction or rotating parts flying off; Specifically, in this step, the specific operations are as follows: S31, performing spectrum analysis on the relative axis vibration data of the measuring point M1 obtained in step S2, and obtaining T 01 The fundamental frequency vibration V of the measuring point M1 at the moment 01bf and T 11 The fundamental frequency vibration V of the measuring point M1 at the moment 11bf ; S32, if the condition is met ≥70% and ≥70%, it is considered that the fundamental frequency is dominant before and after the vibration change, and the process goes to step S4; otherwise, it indicates that there is no contact friction or flying of rotating parts in the steam turbine generator set.

[0037] S4, obtain the duration of the vibration change process of the measuring point M1 relative to the shaft. If the time is less than 1 minute, go to step S5; if the time is more than 1 minute, go to step S6; specifically, in this step, the specific operations are as follows: If the condition T is met 11 -T 01 ≤1min, there is a high possibility that the rotating parts will fly off, go to step S5, if the condition T is met 11 -T 01 >1min, go to step S6.

[0038] S5, the unit load is basically the same, and the pressure of the turbine monitoring section changes, which means that the steam turbine generator set has a rotating component flying off, and the position of the component flying off is near the change in the monitoring section pressure; specifically, in this step, the specific operations are as follows: first confirm that the load change of the unit before and after the vibration fluctuation is no more than 3MW, and then query the pressure value of each monitoring section. If the pressure value of the monitoring section changes, it means that the steam turbine generator set has a rotating component flying off failure.

[0039] S6: This step includes the following two situations: ① If the amplitude of the vibration change does not exceed the trip value (i.e. V 11 <240μm), keep the current operating parameters of the unit stable, quickly start the top shaft oil pump, and observe the change of the relative shaft vibration of the measuring point M1. If the relative shaft vibration of the measuring point M1 slowly decreases to the value before the vibration fluctuation, it means that contact friction has occurred in the steam turbine generator set; otherwise, the contact friction fault is eliminated.

[0040] ② If the amplitude of the vibration changes exceeds the trip value (i.e. V 11 ≥240μm), the vibration protection has been triggered, the unit has stopped and coasted (that is, the unit has stopped). When the speed drops to 500r / min, immediately use the listening needle to listen on site. If an abnormal sound is heard, it means that the steam turbine generator set is currently in contact friction; otherwise, the contact friction fault is eliminated. During the specific operation, listen once every 100r / min drop in speed until the unit is put into cranking. If there is an abnormal sound, it means that the steam turbine generator set is currently in contact friction.

[0041] The implementation process of the present invention is now described in detail through the following Examples 1 and 2 to illustrate the effectiveness and practicality of the present invention.

[0042] Embodiment 1: The steam turbine of the No. 1 steam turbine generator unit of a certain power plant is a C350-24.2 / 0.4 / 566 / 566 supercritical, single intermediate reheat, single shaft, double cylinder double exhaust, one-stage adjustment extraction, condensing steam turbine manufactured by Shanghai Steam Turbine Factory Co., Ltd., equipped with a QFSN-350-2 water / hydrogen / hydrogen cooling generator produced by Shanghai Electric Factory Co., Ltd. The unit shaft system consists of high and medium pressure rotors (HIP), low pressure rotors (LP), generator rotors GEN), exciter brush holders (EXC) and 6 support bearings. The unit shaft system structure diagram is as follows Figure 3 shown.

[0043] From September to November 2023, the unit underwent a Class A overhaul and a comprehensive test of the unit's shaft system vibration after the overhaul. During the unit's operation, the relative shaft vibrations 1X and 1Y at the #1 bearing were abnormal. The vibration fault was immediately diagnosed and identified on site. The specific process is as follows: (1) The on-site operating personnel reported that the relative shaft vibration of the unit exceeded the alarm value (120μm), triggering the alarm signal. After a quick on-site inspection, it was determined that the measuring point where the relative shaft vibration changed significantly was 1X, and its adjacent measuring point was 1Y. Therefore, measuring point 1X was recorded as M1, and measuring point 1Y was recorded as M2.

[0044] (2) Obtain the general frequency and fundamental frequency trend curves of the relative shaft vibration of the measuring point 1X. Figure 4 The trend curves of the general frequency and fundamental frequency of the relative axis vibration of the measuring point 1Y are shown in Figure 5 .

[0045] Depend on Figure 4 It can be obtained that the time T when the vibration of the measuring point 1X relative to the shaft starts to change 01 , the corresponding vibration V 01 , the vibration value after the vibration change V 11 and its corresponding time T11 , listed in Table 1.

[0046] Table 1

[0047] Depend on Figure 5 Combined with Table 1, we can get the vibration change start time T 01 The vibration value V at the measuring point 1Y at the moment 02 , and after vibration changes T 11 The vibration value V at the measuring point 1Y at the moment 12 , listed in Table 2.

[0048] Table 2

[0049] From Table 1 we can get: = >30% From Table 2 we can get: = >30% The relative axis vibration changes of measuring point 1X and measuring point 1Y both meet the conditions, and the relative axis vibration change of measuring point 1X is more obvious.

[0050] (3) Perform spectrum analysis on the relative axis vibration data of measuring point 1X. The waveform spectrum is shown in Figure 6 and Figure 7 .

[0051] Depend on Figure 4 , Figure 6 and Figure 7 Can get, T 01 and T 11 The fundamental frequency vibrations of the measuring point 1X relative to the shaft at the moment are V 01bf and V 11bf , listed in Table 3.

[0052] Table 3

[0053] From Table 1 and Table 3, we can get: >70% From Table 1 and Table 3, we can get: >70% It can be concluded that the change of the vibration of measuring point 1X relative to the shaft is mainly based on the fundamental frequency.

[0054] (4) Based on the previous analysis and calculation, the duration of the relative axis vibration change process of the measuring point 1X is obtained, that is, T 01 and T 11 Time difference: T 11 -T01 8 minutes 6 seconds Since the vibration change process lasts for more than 1 minute, the possibility of contact friction is high.

[0055] (5) The value of the relative shaft vibration of measuring point 1X after the change is 182μm, which is less than the trip protection value (240μm). However, considering that the vibration value is still large, in order to ensure the safety of the equipment, the on-site operator is advised to start the top shaft oil pump immediately. At 16:20:27 on November 10, 2023, the top shaft oil pump was started, and other parameters of the unit remained stable. The vibration operation was observed. At 16:20:02, the relative shaft vibration of 1X began to slowly decrease. After a period of time, its value basically dropped to the value before the vibration fluctuation. See Figure 8 .

[0056] Through the above diagnostic analysis and identification process, it is identified that the unit has a contact friction vibration fault. It is recommended to control the unit operating parameters to be stable so that the unit can operate normally.

[0057] Due to accurate fault identification, unnecessary shutdown of the unit was avoided, thus saving the power plant from economic losses.

[0058] Embodiment 2: The steam turbine of the No. 1 steam turbine generator unit of a certain power plant is a N300-16.7 / 537 / 537-8 subcritical, single intermediate reheat, two-cylinder and two-row steam condensing steam turbine manufactured by Dongfang Steam Turbine Factory Co., Ltd., equipped with a QFSN-300-2-20B water / hydrogen / hydrogen cooling generator produced by Dongfang Electric Machinery Factory Co., Ltd. The unit shaft system consists of a high and medium pressure rotor (HIP), a low pressure rotor (LP), a generator rotor GEN), an exciter brush holder (EXC) and 6 support bearings. The unit shaft system structure diagram is as follows Fig. 9 shown.

[0059] On April 21, 2023, during the normal operation of the unit under load, the vibration suddenly increased, seriously affecting the safe operation of the unit. Using the TDM data equipped with the unit, the vibration fault of the unit was remotely diagnosed, analyzed and identified in the first time. The specific process is as follows: (1) The alarm signal of Unit 1 is triggered, indicating that the relative shaft vibration of the unit exceeds the alarm value (120μm).

[0060] After a quick on-site check by the operation monitoring personnel, it was determined that the measuring point with obvious change in relative shaft vibration was 3Y, and its adjacent measuring point was 3X. Therefore, measuring point 3Y was recorded as M1, and measuring point 3X was recorded as M2.

[0061] (2) Obtain the general frequency and fundamental frequency trend curves of the relative axis vibration of the measuring point 3Y. Fig.10 and Fig.11The trend curves of the general frequency and fundamental frequency of the relative shaft vibration of the measuring point 3X are shown in Fig.12 and Fig.13 .

[0062] Depend on Fig.10 The time T when the vibration of measuring point 3Y relative to the axis starts to change can be obtained 01 , the corresponding vibration V 01 , the vibration value after the vibration change V 11 and its corresponding time T 11 , listed in Table 4.

[0063] Table 4

[0064] Depend on Fig.12 Combined with Table 1, we can get the vibration change start time T 01 The relative axis vibration value V at the measuring point 3X at the moment 02 , and after vibration changes T 11 The relative axis vibration value V at the measuring point 3X at the moment 12 , listed in Table 5.

[0065] Table 5

[0066] From Table 4 we can get: = >30% From Table 5 we can get: = >30% The relative axis vibration changes of measuring point 3X and measuring point 3Y both meet the conditions, and the relative axis vibration change of measuring point 3Y is more obvious.

[0067] (3) Perform spectrum analysis on the relative axis vibration data of measuring point 3Y. The waveform spectrum is shown in Fig.14 and Fig.15 .

[0068] Depend on Fig.11 , Fig.14 and Fig.15 Can get, T 01 and T 11 The fundamental frequency vibrations of the measuring point 3Y relative to the axis at the moment are V 01bf and V 11bf , listed in Table 6.

[0069] Table 6

[0070] From Table 4 and Table 6, we can get: >70% From Table 4 and Table 6, we can get: >70% It can be concluded that the change in the vibration of measuring point 3Y relative to the axis is mainly based on the fundamental frequency.

[0071] (4) Based on the previous analysis and calculation, the duration of the relative axis vibration change process of the measuring point 3Y is obtained, that is, T 01 and T 11 Time difference: T 11 -T 01 52 seconds Since the vibration change process lasts less than 1 minute, the diagnosis shows that there is a high possibility that the rotating parts have fallen off.

[0072] (5) The operating personnel were required to check the pressure values ​​of each monitoring section and the load changes of the unit during the vibration change process. After inquiry, the unit loads were 249MW and 247MW before and after the vibration change, respectively. The loads remained basically unchanged, but the fifth stage extraction steam pressure changed by 0.1MPa.

[0073] Through the above diagnostic analysis and identification process, it is identified that the unit has a rotating component flying off failure, and the component flew off near the fifth stage. It is recommended to strengthen the vibration monitoring operation of the unit and arrange shutdown inspection as soon as possible to avoid causing other secondary hazards and causing greater losses.

[0074] After the unit was monitored and operated for a week, it was shut down for maintenance with the approval of the power grid. After opening the low-pressure cylinder for inspection, it was found that a moving blade of the fourth stage of the low-pressure rotor was broken and a part of the shroud was detached. After replacing the blades and shroud, the relative shaft vibration values ​​of each measuring point after the unit was started were within the excellent value range specified by the national standard (GB / T11348.2-2012).

[0075] The specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection of the claims of the present invention.

Claims

1. A method for quickly identifying contact friction and rotating parts flying off faults, characterized in that: The following steps are involved: When the unit is running, the first measuring point of the bearing has obvious vibration fluctuation phenomenon. If the vibration of the second measuring point of the bearing changes synchronously with the vibration of the first measuring point, it is necessary to continue to judge whether the relative shaft vibration is dominated by the fundamental frequency component before and after the change. Otherwise, it indicates that the unit currently has no contact friction or rotating parts flying off; the second measuring point is the relative shaft vibration measuring point of the first measuring point; When the fundamental frequency component is dominant before and after the relative shaft vibration changes, the duration of the relative shaft vibration change process at the first measuring point is obtained; when the fundamental frequency component is not dominant before and after the relative shaft vibration changes, it indicates that there is no contact friction or rotating parts flying off in the unit; If the duration of the relative shaft vibration change process of the first measuring point is not greater than the preset time, and the unit load is the same and the monitoring section pressure of the unit changes, it indicates that a rotating component of the unit has currently fallen off, and the position of the component falling off is in the area where the monitoring section pressure changes; If the duration of the relative shaft vibration change process of the first measuring point is greater than a preset duration, the amplitude of the shaft vibration change and the unit trip value are used to determine whether contact friction has occurred in the unit.

2. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 1, characterized in that: When the unit is running, obtain the through-frequency and fundamental frequency vibration trend curves within a period of time before and after the vibration fluctuation of the first measuring point, perform data analysis on the through-frequency and fundamental frequency vibration trend curves, and judge whether obvious vibration fluctuation occurs at the first measuring point based on the analysis results.

3. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 2, characterized in that: When analyzing the data of the through-frequency and fundamental frequency vibration trend curves, the time T when the vibration fluctuation of the first measuring point starts is obtained on the through-frequency and fundamental frequency vibration trend curves. 01 And the corresponding vibration V 01 , obtain the vibration value V after the first measuring point moves on the general frequency and fundamental frequency vibration trend curve 11 and time T 11 , set the first measuring point to meet the following conditions: ≥30% Get the second measuring point at T 01 Vibration of the moment 02 and T 11 Vibration of the moment 12 , if the following conditions are met: ≥20% It is determined that the vibration of the second measuring point changes synchronously with the vibration of the first measuring point, otherwise it indicates that no contact friction or flying of rotating parts occurs in the unit.

4. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 3, characterized in that: When judging whether the relative shaft vibration before and after the change is dominated by the fundamental frequency component, the spectrum analysis of the relative shaft vibration data of the first measuring point is performed to obtain the relative frequency component of the first measuring point at T 01 The fundamental frequency vibration V 01bf and T 11 The fundamental frequency vibration V at time 11bf ; If the following conditions are met: ≥70% and ≥70% It is judged that the fundamental frequency component is dominant before and after the relative shaft vibration changes, otherwise it indicates that the fundamental frequency component is not dominant before and after the relative shaft vibration changes.

5. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 1 or 4, characterized in that: The frequency of the fundamental frequency component is 50 Hz.

6. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 3, characterized in that: The preset duration is set to 1 minute.

7. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 1, characterized in that: If the duration of the relative shaft vibration change process of the first measuring point is not greater than the preset time, and the unit load change is not greater than 3MW, it is considered that the unit load is the same.

8. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 1, characterized in that: The process of judging whether contact friction occurs in the unit by using the amplitude of the shaft vibration change and the trip value of the unit includes: If the amplitude of the shaft vibration after the change is less than the over-jump value, keep the current operating parameters of the unit stable, start the unit's top shaft oil pump, and if the relative shaft vibration of the first measuring point drops to the value before the vibration fluctuation, it indicates that the unit is currently experiencing contact friction; otherwise, the contact friction fault is eliminated; If the amplitude of the shaft vibration change is above the trip value and has caused the unit to shut down, use a stethoscope to listen to the sound on site when the speed drops to 500r / min. If an abnormal sound is heard, it indicates that contact friction has occurred in the unit; otherwise, the contact friction fault is eliminated.

9. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 8, characterized in that: The trip value of the unit is 240μm; When using a stylus to listen on site, listen every time the speed drops by 100r / min until the unit is started. If an abnormal sound is heard, it indicates that contact friction has occurred in the unit; otherwise, the contact friction fault is eliminated.

10. A method for quickly identifying contact friction and rotating parts flying-off faults according to claim 1, characterized in that: The angle between the corresponding radii of the first measuring point and the second measuring point on the bearing is 90°.

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