JPH054618B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to early detection and diagnosis of abnormal signs in the operating conditions of high-speed rotating machinery in steam turbines, generator plants, etc., and detection of shaft vibration. The present invention relates to a method for diagnosing vibrations of rotating machines based on values and a vibration diagnosing device thereof.

(Prior Art) Generally, most abnormalities during operation of rotating machines appear as changes in shaft vibration. Particularly in steam turbines and power generating units for power plants, rotors weighing tens to hundreds of tons rotate at high speed, and even minute vibrations, if abnormal, can lead to serious accidents. . Therefore, several methods and diagnostic devices have been proposed for early detection of abnormalities in rotating machines by analyzing these vibrations in detail, as shown in, for example, Japanese Patent Laid-Open No. 128128/1983.

FIG. 10 shows a conventional diagnostic device for the steam turbine/generator unit 5. Vibration detectors 10a, . . . 10i are provided in bearings 9a, . There is. Additionally, there is a tachometer 11 that detects the rotational speed of the rotor, a phase reference pulse transmitter 12 that transmits a reference pulse when detecting the phase of shaft vibration in each bearing section 9a,...9i, and a generator output. A group of various sensors 13 are installed to detect the operating status of the plant, such as (load), steam temperature, and bearing temperature.

The outputs of the tachometer 11 and the various sensor groups 13 are sent to the operation monitoring device 15 provided in the central operation panel 14, and the vibration detectors 10a, . . . 10i
The output of the phase reference pulse transmitter 12 is sent to a vibration monitoring device 16 provided in the central operation panel 14 and constantly checked, and if it exceeds a predetermined limit value, a command signal is issued to the alarm device 17. Alarm and automatic trip signals are output. In addition, vibration detectors 10a, ... 10i, tachometer 11, phase reference pulse transmitter 12, and various sensor groups 13
The output is also sent to an analog type continuous recorder 18 and recorded. In addition, vibration detectors 10a,...1
The vibration data that is the output of the Oi and phase reference pulse generator 12 is sent to the A/
The signal is converted into D and sent to the shaft vibration diagnosis device 3 for diagnosis. This shaft vibration diagnosis device 3 is a system that uses a computer to perform abnormality diagnosis and support an operator. The A/D converted vibration data is compared with a predetermined threshold value, and an abnormality sign is detected by an abnormality sign detection device 19. In addition, the above A/D
The frequency analyzer 20 analyzes the frequency component distribution of shaft vibration based on the converted vibration data. The diagnostic unit 22 then diagnoses the cause of the abnormality symptom based on the outputs of the various sensor groups 13, the abnormality symptom detection device 19, and the frequency analyzer 20, as well as past history data stored in the memory 24. The results are displayed on the display device 23, and various data used in the diagnosis and the diagnosis results are stored in the memory 24.

(Problem to be Solved by the Invention) Since the shaft vibration of rotating machinery can change rapidly depending on the degree of abnormality in the operating condition, early detection of abnormality symptoms and early diagnosis of the degree of abnormality are required. Real-time characteristics are required. However, since these diagnostic results are expected to directly contribute to plant operation, prevention of malfunctions in detecting abnormality symptoms is also an important issue. For example, FIG. 11 shows the display method in Japanese Patent Application Laid-open No. 142902/1983 as a conventional method for detecting abnormality symptoms, in which the normal range, alarm range, Judgment areas are divided into trip areas and the degree of urgency is judged. Furthermore, the amplitude level and amplitude increase rate used for the above judgment are determined as the measured value V _i at the detection time t _i as shown in FIG. The value obtained from the previous n pieces of data V _i-o+1 to _{V i} using the least squares method using the linear approximation formula V=α・T+β...(1), V (vibration amplitude level), α (amplitude increase rate) ; slope) is used. Here, T is a sampling time determined by the sampling interval and the number of samples.

By performing such processing, it is possible to prevent malfunctions in abnormality symptom detection due to data variations. However, by averaging the changes, there is a problem that in the case of an abnormality accompanied by minute changes, the symptoms cannot be detected. An example of a means to solve such problems is the patent application No. 62-260193 filed by the present applicant.
proposed in No. According to this method, sudden events due to mechanical imbalance as shown in FIG.
As shown in the figure, it becomes possible to distinguish between rubbing events, but this alone is not sufficient.

That is, although the above-mentioned means can identify cases where the direction of amplitude change increases in one direction, it cannot detect events such as random points that instantaneously repeat increases and decreases. Furthermore, in the case of random points, the problem is the variation in the data itself, so if the characteristics are eliminated by averaging the data, it will be difficult to distinguish between them. Therefore, at present, the system relies on off-line determination based on the operator's specialized knowledge.

The present invention was made in consideration of the above circumstances, and
A method for diagnosing vibrations of rotating machines that uses objective evaluation criteria to detect irregular points, which was conventionally done by humans, and enables processing by computer to detect abnormal signs of shaft vibration at an early stage and strengthen the diagnostic function. The present invention aims to provide a vibration diagnosis device for the same.

[Structure of the invention]

(Means for Solving the Problems) A vibration diagnosis method for a rotating machine according to the present invention detects shaft vibration of the rotating machine with a detector, converts this detection signal into A/D using a vibration monitoring means, and monitors the vibration. A plurality of vibration data detected by the means from the present time to a predetermined time in the past are sent to the standard deviation monitoring means to calculate the standard deviation, and while monitoring this standard deviation, the vibration data is calculated based on the monitoring result. When the data is determined to be abnormal, a continuous random point determination means determines whether or not it is a random point event accompanied by continuous irregular vibration, and further, when it is determined that the data is a continuous random point event, It is characterized in that the vibration data is sent to a display means and displayed.

Further, when the vibration data is not determined to be a continuous random point by the continuous random point determination means,
The sudden event detection means may detect whether the sudden event is due to mechanical imbalance or the event of a sudden increase in amplitude due to rubbing, and the one-time random point determination means may detect whether it is a one-time random point event that occurs instantaneously.

On the other hand, the vibration diagnosis device for a rotating machine according to the present invention includes a detector that detects shaft vibration of the rotating machine, A/D converts the detection signal of the detector, and a plurality of signals from the present time to a certain predetermined time in the past. vibration monitoring means for detecting vibration data; standard deviation monitoring means for calculating a standard deviation from the vibration data detected by the vibration monitoring means; and a standard deviation monitoring means for determining that the vibration data is abnormal by the standard deviation monitoring means. continuous random point determination means that determines whether the event is a random point event accompanied by continuous irregular vibration when the vibration occurs; The present invention is characterized by comprising a display means for displaying.

Further, when the continuous random point determining means determines that the vibration data is a non-continuous random point, sudden event detecting means detects whether the sudden event is due to mechanical imbalance or an event of sudden increase in amplitude due to rubbing. It is also possible to provide a single random point determining means for detecting a single random point event that occurs instantaneously.

(Function) In the present invention having the above configuration, the axial vibration of the rotating machine is detected by the detector, this detection signal is A/D converted by the vibration monitoring means, and from the present moment detected by the vibration monitoring means. A plurality of vibration data up to a predetermined time in the past are sent to the standard deviation monitoring means. Next, if the standard deviation monitoring means determines that there is a variation in the vibration data, it is determined to be abnormal, and if the continuous random point determination means continues for a certain period of time, it is determined that the vibration data is a continuous disturbance. It is determined that it is a point event, and its vibration data is displayed on the display means.

On the other hand, if it is not determined to be a continuous irregular point event, the sudden event detection means determines whether the event is a sudden change due to mechanical imbalance or a rapid increase in vibration due to rubbing. A random point determination means determines whether the event is a one-off, instantaneous event.

Therefore, according to the present invention, it is possible to determine not only a random point event in which the change in amplitude increases unilaterally, but also a random point event in which an increase and a decrease instantaneously repeat.

(Example) The present invention will be described below based on an illustrative example.

FIG. 1 shows a vibration diagnosis device for a rotating machine according to an embodiment of the present invention. The vibration diagnosis device of this embodiment, like the conventional diagnosis device shown in FIG. Vibration detectors 10a, . . . 10i in sections 9a, . Detection signals from the vibration detectors 10a, . . . 10i and the various sensor groups 13 are sent to a central operation panel 14. The central operation panel 14 is the operation monitoring device 1
5. A vibration monitoring device 16 as a vibration monitoring means for A/D conversion, an alarm device 17, and a recorder 18 are provided.

The vibration diagnosis apparatus shown in FIG. 1 includes a standard deviation monitoring section 1 as a standard deviation monitoring means for calculating the standard deviation of vibration data, a continuous random point determination section 2 as a continuous random point determination means, and a shaft vibration diagnosis section. A sudden event detection device 21 of the device 3 and a one-time random point determining unit 4 as a one-time random point determining means are added to the conventional example shown in FIG. 10, and other than these are described in the conventional technology section. Since this has already been explained, the explanation will be omitted.

The vibration monitoring device 16 of the central operation panel 14 incorporated in the vibration diagnosis device is connected to the abnormality sign detection device 19 of the shaft vibration diagnosis device 3 via the standard deviation monitoring section 1 and the continuous irregular point determination section 2. Detection device 1
A monitoring determination signal is input to 9. Further, the operation monitoring device 15 of the central operation panel 14 includes the shaft vibration diagnosis device 3.
is input to the diagnostic section 22 of the.

By the way, in FIG. 1, the vibration detectors 10a,
...10i and the vibration data which is the output data of the phase reference pulse transmitter 12 is A/D converted by the vibration monitoring device 16 and sent to the standard deviation monitoring section 1. This standard deviation monitoring unit 1 detects abnormal signs, and if no abnormal signs are detected, it is determined to be normal. That is, only when the standard deviation monitoring section 1 detects an abnormality sign, the vibration data is sent to the continuous random point determination section 2 to determine whether there is a continuous random point. Here, if it is determined that the point is a continuous random point, the vibration data is not sent to the shaft vibration diagnosis device 3, and the result is directly output to the display device 23.

On the other hand, if the continuous random point determination unit 2 does not determine that the continuous random point is a continuous random point, the vibration data is sent to the shaft vibration diagnosis device 3.

The shaft vibration diagnosis device 3 includes an abnormality symptom detection device 19,
A frequency analyzer 20, a sudden event detection device 21,
It has a diagnostic section 22, a display device 23, and a memory 24, and the vibration data from the continuous random point determination section 2 is transmitted to a frequency analyzer 20, where the distribution of frequency components is determined and abnormality signs are determined. Detection device 1
9 is also transmitted.

Further, the detection signal from the abnormality sign detection device 19 is transmitted to the sudden event detection device 21, and this sudden event detection device 21 determines the sudden event caused by mechanical imbalance or the event of sudden increase in amplitude due to rubbing, and makes a diagnosis. If each event can be detected as a result of the diagnosis in the unit 22, the results are outputted to the display device 23 for display, and various data used in the diagnosis and the diagnosis results are stored in the memory 24.

On the other hand, if the shaft vibration diagnosis device 3 is unable to detect each of the above-mentioned events, the vibration data is sent to a single random point determining section 4, where a single random point is determined. Here, if it is determined that it is a single random point, the result is output to the display device 23.

In this embodiment, since it is a prerequisite that vibration data can be obtained, the vibration detectors 10a, . . . 1
0i, a vibration monitoring device 16, or other means for acquiring vibration data is required. Note that the vibration data obtained from the vibration monitoring device 16 of the central operation panel 14 is an overall vibration amplitude including all frequency components. The operation of performing vibration diagnosis using such vibration data will be explained.

First, the standard deviation monitoring unit 1 determines whether or not there is an abnormality based on whether there is variation in a plurality of pieces of vibration data from the current time to a certain predetermined time in the past. Here, if it is determined that there is variation in the vibration data, the vibration is determined to be abnormal,
If the dispersion continues for a certain period of time or more, the continuous irregular point determination unit 2 determines that the irregular point event is accompanied by continuous irregular vibration. This kind of random point event is defined as continuous random point, and a typical example is the third one.
As shown in the figure.

Also, if it is not determined to be a continuous random point,
As described above, two events are distinguished: a sudden change due to mechanical imbalance (a typical example is shown in FIG. 5) and an amplitude sudden increase due to rubbing (a typical example is shown in FIG. 6). Here, for an event that cannot be determined, the one-time random point determination unit 4 determines whether or not it is a one-off, instantaneous random point event. Such a random point event is defined as a single random point, and a typical example thereof is shown in FIG.

Next, FIG. 2 is a flowchart showing the operation of each part of this embodiment. In this figure, the parts surrounded by dashed lines correspond to the operations of the parts 1, 2, 3, and 4 in FIG.

First, in step a, the vibration monitoring device 16 detects a plurality of pieces of vibration data from the current time to a predetermined time in the past, and then in step b, the standard deviation monitoring unit 1 inputs the vibration data to detect the next vibration data. Calculate the (population) standard deviation σ _i from the formula.

σ _i =1/n-1 { _i 〓 ^j=i-n+1 (V _j −V _av ) ² } ^1/2 ...(2) In the above formula (2), n is the number of vibration data, V _i
is the vibration data of the current time t _i , V _i-o+1 is the n vibration data before V _i , V _av is the n vibration data V _i-o+1 ,
...It is the average value of V _i .

Since the above standard deviation σ _i indicates the degree of data dispersion, the degree of data dispersion can be determined from the following equation.

σ _i ≧ε (3) Here, ε is a threshold value for determining the degree of variation. If this formula (3) is satisfied, the degree of data variation is large, and it is determined that the currently detected vibration is abnormal. However, if the number n of vibration data is set large, the standard deviation σ _i will become smaller even under the same conditions, and it is necessary to set the threshold value taking into account that the degree of variation in data that is considered normal varies depending on the plant. be. (Step c).

Next, when the standard deviation monitoring unit 1 determines that the vibration data is abnormal, that is, in step c, σ _i
When it is determined that ≧ε, in step d, the continuous random point determination section 2 determines whether the determination condition of equation (3) continues to hold true for a certain period of time thereafter. Since the purpose of this determination is to capture the characteristics of the relationship between the vibration waveform and standard deviation shown in FIGS. 3 to 6, the characteristics that can be read from each figure will be explained.

Figures 3A and 3b show the amplitude V on the vertical axis for a disordered point event (continuous disordered point) accompanied by continuous irregular vibrations.
and the standard deviation σ are taken and shown arranged vertically with the time axis on the horizontal axis. In this case, after the event occurs,
It has the characteristic that the judgment condition of equation (3) is satisfied and the condition continues to be satisfied thereafter.

FIGS. 4A and 4B show a random point event that occurs instantaneously (single point random point) in the same format as the front. In this case, after the occurrence of the event, the judgment condition of equation (3) is satisfied, but the condition is not satisfied after a time Δt after the condition is satisfied, and the system returns to a normal state.

5A and 5B show sudden events caused by mechanical imbalance in a format similar to that of FIG. 3.
In this case as well, the determination condition of equation (3) has the same characteristics as in FIG.

Using the above characteristics, continuous random points can be detected using the following equation.

Δt≧ε′ (4) Here, ε′ is a threshold value for determining a continuous random point. If this equation (4) is satisfied, it is determined that the judgment condition of equation (3) continues to hold for a certain period of time (ε' or more), and the diagnosis result becomes a continuous random point (step e).

On the other hand, in step d, the continuous random point determination unit 2
When not diagnosed as a continuous irregular point, the shaft vibration diagnosis device 3 can detect a sudden change event due to mechanical imbalance and an event of sudden increase in amplitude due to rubbing.
Here, since the diagnosis method of the shaft vibration diagnosis device 3 is described in detail in Japanese Patent Application No. 62-260193, an outline thereof will be explained. Figure 7 shows the process of detecting sudden events due to mechanical imbalance using _the above diagnostic _method . _i-1 ……(5) Difference in average value ΔV _n ……(6) Difference in predicted value ΔV _c ……(7) Determine whether it exceeds each limit value (step f), and check the above three items. If all of the values exceed their respective limit values, if the following equation is satisfied, it is diagnosed as a sudden event caused by mechanical imbalance (step g).

ΔV _p ΔV _n ΔV _c ...(8) Here, the difference in average value ΔV _n is the average value of n pieces of amplitude data V _io , ...V _i-1 before abnormality symptom detection (t _i ), n amplitude data V _i after detection,...
Indicates the difference from the average value of V _i+o-1 , and the difference in predicted value ΔV _c is the vibration amplitude value at detection time t _i obtained by the least squares method using a linear approximation formula from vibration data before abnormal symptom detection. This is the difference between the vibration amplitude value at time t _i and the vibration amplitude value obtained at time t i using a first-order approximation formula using the least squares method from the data after detection. Although V _p is used as the criterion in equation (8),
In the detection of single random points described later, this is ΔV _n
This is because ΔV _c may occur.

Next, Figure 8 shows the process of detecting an event of rapid amplitude increase due to rubbing using the same diagnostic method as above, and in the same figure, the items (5), (6), and (7) above are all If the limit value is exceeded, if the following equation is satisfied, it is diagnosed that the amplitude has suddenly increased due to rubbing (step h).

ΔV _n >> ΔV _c ...(9) Furthermore, if the shaft vibration diagnosis device 3 does not diagnose a sudden change due to mechanical imbalance or a rapid increase in amplitude due to rubbing in step f, the single random point determination unit 4 Determine whether it is a single random point or not. Figure 9 shows a single random point and the detection process using the same diagnostic method as the shaft vibration diagnosis device 3.
If each item (5), (6), and (7) all exceeds the limit value, it is diagnosed as a single random point if the following formula is satisfied (step i).

ΔV _p ＞＞ΔV _n ...(10) Therefore, this embodiment automatically discriminates random point events in which the change in amplitude increases unilaterally and random point events in which increases and decreases are instantaneously repeated. can do.

〔Effect of the invention〕

As explained above, according to the vibration diagnosis method for a rotating machine according to the present invention, by monitoring the standard deviation calculated from vibration data, it is possible to determine whether there are abnormal signs in the operating state of the rotating machine. Automatically detects and instantly determines whether or not it is a random point event accompanied by continuous irregular vibrations. As a result, early detection of abnormal shaft vibration symptoms becomes possible, and the diagnostic function can be strengthened.

Furthermore, the sudden event determining means automatically determines sudden events caused by mechanical imbalance and events of sudden amplitude increase due to rubbing, and the sudden random point determining means automatically determines single random point events that occur instantaneously. I can do it.

Furthermore, according to the vibration diagnosis device for rotating machinery according to the present invention, it is possible to estimate the cause of shaft vibration abnormalities online and in real time with more precision, and to provide timely support to power plant operators. Accidents caused by human error can be prevented, and maintenance management of rotating machinery, such as preventive maintenance, can be facilitated by constantly monitoring trends of abnormal signs, and the reliability of the plant can be improved. play.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the vibration diagnosis device for rotating machinery according to the present invention, Fig. 2 is a flowchart explaining the operation of the embodiment shown in Fig. 1, and Figs. 3A and B are continuous diagrams. Graphs showing changes in amplitude V and standard deviation σ when a disordered point event (continuous disordered point) accompanied by irregular vibrations occur in Figures 4A and B are graphs showing changes in the amplitude V and standard deviation σ when a disordered point event (continuous disordered point) accompanied by irregular vibrations occurs. Graphs showing changes in the amplitude V and standard deviation σ when a single random point) occurs; Figures 5A and B show changes in the amplitude V and standard deviation σ when a sudden incident due to mechanical imbalance occurs. Figures 6A and B are graphs showing changes in amplitude V and standard deviation σ when an event of rapid amplitude increase due to rubbing occurs, and Figure 7 is a graph when a sudden change event due to mechanical imbalance occurs. FIG. 8 is a graph explaining a method of detecting an amplitude change when an event of sudden increase in amplitude occurs due to rubbing; FIG.
The figure is a graph explaining a method for detecting amplitude changes when a single, instantaneous random point event occurs, and Figure 10 is a block diagram showing a conventional vibration diagnosis device.
FIGS. 11 and 12 are graphs illustrating a shaft vibration monitoring method of a conventional vibration diagnosis device. DESCRIPTION OF SYMBOLS 1...Standard deviation monitoring unit, 2...Continuous disturbance point determination unit, 3...Shaft vibration diagnosis device, 4...Single disturbance point determination unit, 5...Steam turbine/generator unit, 6
... High and intermediate pressure turbine, 7a, 7b ... Low pressure turbine, 8 ... Generator, 9a to 9i ... Bearing section, 10
a~10i...Vibration detector, 11...Tachometer, 1
2... Phase reference pulse transmitter, 13... Various sensor groups, 14... Central operation panel, 15... Operation monitoring device, 16... Vibration monitoring device, 17... Alarm device,
18... Recorder, 19... Abnormality sign detection device, 2
0... Frequency analyzer, 21... Sudden event detection device, 22... Diagnosis section, 23... Display device, 24...
…memory.

Claims (1)

[Claims] 1. Shaft vibration of a rotating machine is detected by a detector, this detection signal is A/D converted by a vibration monitoring means, and a predetermined period in the past from the present moment detected by the vibration monitoring means is detected. The standard deviation is calculated by sending a plurality of pieces of vibration data up to the time to the standard deviation monitoring means, and when the standard deviation is monitored and the vibration data is determined to be abnormal based on the monitoring result, the continuous A continuous random point determining means determines whether the point is a random point event accompanied by irregular vibrations, and further, when it is determined that the event is a continuous random point event, the vibration data is sent to a display means and displayed. Vibration diagnosis method for rotating machinery. 2. When the continuous random point determination means does not determine that the vibration data is a continuous random point, the sudden event detection means detects whether the sudden event is due to mechanical imbalance or an event where the amplitude suddenly increases due to rubbing. 2. The vibration diagnosing method for a rotating machine according to claim 1, further comprising the step of detecting whether a single random point event occurs instantaneously by a single random point determining means. 3. A detector that detects shaft vibration of a rotating machine, a vibration monitoring means that A/D converts the detection signal of this detector and detects a plurality of vibration data from the current moment to a certain predetermined time in the past; standard deviation monitoring means for calculating a standard deviation from vibration data detected by the vibration monitoring means; and continuous irregular vibration when the standard deviation monitoring means determines that the vibration data is abnormal. It is characterized by comprising a continuous random point determination means for determining whether it is a random point event, and a display means for displaying vibration data when the continuous random point determination means determines that it is a continuous random point event. Vibration diagnostic device for rotating machinery. 4. Sudden event detection means for detecting whether the sudden event is due to mechanical imbalance or a sudden increase in amplitude due to rubbing when the continuous random point determining means determines that the vibration data is a non-continuous random point; 4. The vibration diagnosis device for a rotating machine according to claim 3, further comprising a single random point determining means for detecting a single random point event that occurs instantaneously.