CN110608887A - A Fault Judgment Method of Turbine Oil Film Whirl Vibration - Google Patents

Abstract

The invention relates to a method for judging a turbine oil film whirl vibration fault, which comprises the following steps of: the method includes the steps of performing vibration data acquisition; carrying out spectrum analysis; performing a speed-up and speed-down vibration test; fourthly, analyzing acceleration and deceleration vibration data; fifthly, carrying out a temperature change test; sixthly, analyzing oil temperature test data. The invention designs the lifting rotating speed test and the oil temperature changing test to judge the oil film whirl vibration fault, greatly improves the judgment accuracy, has simple, convenient, quick and effective judgment process, does not depend on experience, can be judged by any worker according to the method, and can well guide production application.

Description

A Fault Judgment Method of Turbine Oil Film Whirl Vibration

technical field

The invention belongs to the technical field of steam turbine detection, in particular to a method for judging a steam turbine oil film eddy vibration fault.

Background technique

The problem of excessive vibration will occur during the operation of the steam turbine. The standard stipulates that the bearing vibration of the steam turbine generator set with a capacity of 300MW and above needs to be dealt with if the vibration exceeds 120μm. It is also excessive vibration, but there may be various reasons. If you want to carry out effective treatment, you first need to analyze and judge the cause of excessive vibration. Only after the cause is determined can you carry out targeted treatment.

Among the various reasons that cause the excessive vibration of the steam turbine, the oil film whirl is a kind of fault type that is difficult to determine. Because its fault characteristics are relatively close to steam flow excitation and friction friction, it is easy to be confused and not easy to distinguish, but its treatment method is very different from steam flow excitation and friction friction, so whether it can be accurately judged depends on appears to be particularly important. Moreover, if the oil film eddy cannot be treated in time, it is likely to develop into oil film vibration. The destructive power of oil film vibration is extremely high, and the amplitude rises in a divergent trend, which is likely to cause damage or even disintegration of equipment, resulting in vicious accidents. But at present, the judgment of the oil film whirl vibration fault can only rely on experts with rich experience, and there is no simple, effective and reliable judgment method. This has caused great inconvenience to the safe operation and maintenance of the power plant. Therefore, it is very necessary to invent an effective and highly operable oil film whirl vibration fault diagnosis method.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a simple, fast, reliable and stable method that transforms the work of relying on vibration diagnosis experts to analyze by experience in the past, and any power plant staff can complete the analysis according to the operation steps A steam turbine oil film whirl vibration fault judgment method for the judgment of the fault type.

The concrete technical scheme that the present invention adopts is as follows:

A steam turbine oil film whirl vibration fault judgment method, characterized in that: comprising the following steps:

(1) Vibration data collection, using professional vibration data collection and analysis instruments to obtain X and Y vibration data of bearings with excessive vibration under the working condition of the unit;

⑵ View the vibration spectrum;

If there is a single-peak low-frequency vibration component in the frequency spectrum, and the amplitude of the component reaches more than 20% of the general frequency amplitude, it is determined that the unit may have the problem of oil film whirl, and it is necessary to turn to the next step for judgment;

If there is no component in this frequency range, it can be determined that there is no oil film whirl;

(3) Keep the vacuum of the unit, lubricating oil temperature and other parameters unchanged, gradually reduce the speed of the unit to 50% of the working speed, and then increase it to the working speed, and record the vibration data during the whole process;

(4) Check whether the frequency of the low-frequency vibration component in the vibration spectrogram at each speed changes with the change of the speed;

If it changes, it is judged that there may be oil film whirl, and it is necessary to transfer to the next step of judgment;

If the frequency does not change but remains consistent all the time, it can be determined that there is no oil whirl;

(5) Keep the unit speed and other operating parameters unchanged, gradually increase the bearing lubricating oil temperature by 5°C from the normal value, and stay for 5 minutes for every 1°C increase during the period and record the vibration data; then reduce the lubricating oil temperature to 5° below the normal temperature °C, during the same period, stay for 5 minutes for each change of 1 °C and record the vibration data;

⑹ Check the amplitude of the low-frequency vibration component of the bearing at each temperature;

If the amplitude of this component shows a trend of decreasing as the temperature increases and increasing as the temperature decreases, then it can be finally determined that the problem of excessive vibration of the unit is oil film whirl;

If there is no such trend, it can be finally determined that the problem of excessive unit vibration is not caused by oil film whirl.

Furthermore, the single-peak low-frequency vibration component in step (2) is a single-peak low-frequency vibration component of 0.3-0.5 times frequency.

Advantage and beneficial effect of the present invention are:

The present invention designs the test of rising and falling speed and the test of changing oil temperature to determine the fault of vortex vibration of oil film, which greatly improves the accuracy of judgment. The judgment process is simple, fast and effective. It does not depend on experience, and any worker can complete it according to the method. Judgment can be a good guide for production application.

Description of drawings

Figure 1 is a schematic diagram of the present invention.

Detailed ways

The present invention is further described in detail through the following examples, but the technical content described in this example is illustrative rather than limiting, and should not limit the protection scope of the present invention accordingly.

A steam turbine oil film whirl vibration fault judgment method, as shown in Figure 1, the innovation of the present invention is: comprise the following steps:

(1) Vibration data collection, using professional vibration data collection and analysis instruments to obtain X and Y vibration data of bearings with excessive vibration under the working condition of the unit;

⑵ View the vibration spectrum;

If there is a single-peak low-frequency vibration component of 0.3-0.5 times frequency in the frequency spectrum, and the amplitude of the component reaches more than 20% of the general frequency amplitude, it is determined that the unit may have the problem of oil film whirl, and it is necessary to turn to the next step for judgment;

If there is no component in this frequency range, it can be determined that there is no oil film whirl;

(3) Keep the vacuum of the unit, lubricating oil temperature and other parameters unchanged, gradually reduce the speed of the unit to 50% of the working speed, and then increase it to the working speed, and record the vibration data during the whole process;

(4) Check whether the frequency of the low-frequency vibration component in the vibration spectrogram at each speed changes with the change of the speed;

If it changes, it is judged that there may be oil film whirl, and it is necessary to transfer to the next step of judgment;

If the frequency does not change but remains consistent all the time, it can be determined that there is no oil whirl;

(5) Keep the unit speed and other operating parameters unchanged, gradually increase the bearing lubricating oil temperature by 5°C from the normal value, and stay for 5 minutes for every 1°C increase during the period and record the vibration data; then reduce the lubricating oil temperature to 5° below the normal temperature °C, during the same period, stay for 5 minutes for each change of 1 °C and record the vibration data;

⑹ Check the amplitude of the low-frequency vibration component of the bearing at each temperature;

If the amplitude of this component shows a trend of decreasing as the temperature increases and increasing as the temperature decreases, then it can be finally determined that the problem of excessive vibration of the unit is oil film whirl;

If there is no such trend, it can be finally determined that the problem of excessive unit vibration is not caused by oil film whirl.

Example

Take the vibration fault treatment of No. 1 bearing of No. 4 unit of a power plant as an example. The vibration of the bearing increased during operation.

The first step is to use professional instruments to test the vibration data of the unit in the X and Y directions in the working state, and generate a spectrogram. This process is completed by professional software.

The second step is to perform spectrum analysis according to the spectrogram. It is found that there is a large vibration component at the frequency of 25Hz in both X and Y directions, of which the X-direction vibration component is 56 μm and the general frequency amplitude is 83 μm; the Y-direction vibration component is 45 μm and the general frequency amplitude is 78 μm. The proportions were 67% and 58%, both exceeding 20%. The operating frequency of the unit is 50Hz, and 25Hz is exactly 0.5 times the frequency. Based on the above two points, it is determined that the unit may have the problem of oil film whirl, and it needs to be transferred to the next step of judgment.

The third step is to carry out the lifting speed test. Keep the vacuum of the unit, lubricating oil temperature and other parameters unchanged, gradually reduce the speed of the unit to 50% of the working speed, that is, 1500rpm, and then increase it to the working speed, and record the vibration data during the whole process.

The fourth step is to analyze the speed-up and down-speed vibration data. The frequency of the low-frequency component of the unit is always kept at 50% of the power frequency during the entire process of speed up and down, that is, 0.5 times the frequency. Rather than a fixed frequency remains constant. Therefore, it is still judged that the vibration fault of the unit may be oil film whirl, and it needs to be transferred to the next step of judgment.

The fifth step is to change the oil temperature test. Keep the unit speed and other operating parameters unchanged, gradually increase the bearing lubricating oil temperature by 5°C from the normal value, and stay for 5 minutes for every 1°C increase during the period and record the vibration data; then reduce the lubricating oil temperature to 5°C lower than the normal temperature , During the same period, every change of 1 ℃ stays for 5 minutes and records the vibration data.

The sixth step is data analysis of variable oil temperature test. The 0.5-fold frequency vibration component of the unit showed a trend of decreasing as the temperature increased and increasing as the temperature decreased in the variable oil temperature test.

The present invention designs the test of rising and falling speed and the test of changing oil temperature to determine the fault of vortex vibration of oil film, which greatly improves the accuracy of judgment. The judgment process is simple, fast and effective. It does not depend on experience, and any worker can complete it according to the method. Judgment can be a good guide for production application.

Claims (2)

1. a steam turbine oil film whirl vibration fault determination method, is characterized in that: comprise the following steps: (1) Vibration data collection, using professional vibration data collection and analysis instruments to obtain X and Y vibration data of bearings with excessive vibration under the working condition of the unit; ⑵ View the vibration spectrum; If there is a single-peak low-frequency vibration component in the frequency spectrum, and the amplitude of the component reaches more than 20% of the general frequency amplitude, it is determined that the unit may have the problem of oil film whirl, and it is necessary to turn to the next step for judgment; If there is no component in this frequency range, it can be determined that there is no oil film whirl; (3) Keep the vacuum of the unit, lubricating oil temperature and other parameters unchanged, gradually reduce the speed of the unit to 50% of the working speed, and then increase it to the working speed, and record the vibration data during the whole process; (4) Check whether the frequency of the low-frequency vibration component in the vibration spectrogram at each speed changes with the change of the speed; If it changes, it is judged that there may be oil film whirl, and it is necessary to transfer to the next step of judgment; If the frequency does not change but remains consistent all the time, it can be determined that there is no oil whirl; (5) Keep the unit speed and other operating parameters unchanged, gradually increase the bearing lubricating oil temperature by 5°C from the normal value, and stay for 5 minutes for every 1°C increase during the period and record the vibration data; then reduce the lubricating oil temperature to 5° below the normal temperature °C, during the same period, stay for 5 minutes for each change of 1 °C and record the vibration data; ⑹ Check the amplitude of the low-frequency vibration component of the bearing at each temperature; If the amplitude of this component shows a trend of decreasing as the temperature increases and increasing as the temperature decreases, then it can be finally determined that the problem of excessive vibration of the unit is oil film whirl; If there is no such trend, it can be finally determined that the problem of excessive unit vibration is not caused by oil film whirl. 2. A steam turbine oil film whirl vibration fault determination method according to claim 1, characterized in that: the single-peak low-frequency vibration component in step (2) is a single-peak low-frequency vibration component of 0.3-0.5 times frequency.