JPS6359091B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method and apparatus for diagnosing vibrations of a rotating machine. In particular, it detects the rotation speed and vibration of the rotor's both end bearings when the rotor of a rotating machine rotates, and diagnoses abnormal vibrations caused by unbalance that occurs in the rotating shaft based on pre-stored vibration characteristics of the rotor. The present invention relates to a method and apparatus for evaluating an unbalanced position and determining the amount of unbalance occurring at this unbalanced position. This type of technology can be used for maintenance of rotating equipment such as turbines. Particularly recently, as thermal and nuclear power plants have increased in capacity, there has been a need to further improve the reliability of their main equipment, such as turbine generators.
In order to supply power smoothly, it is essential to quickly perform maintenance after an abnormality occurs in equipment.
Therefore, vibration diagnosis of this type of rotating machine has become extremely important. Just as there are various causes for abnormalities in rotating machines, there are also various abnormal phenomena, but abnormal cases of shaft vibration are particularly common.
There is also concern that this may lead to serious failure. Furthermore, since the rotating shaft systems used in power plants such as turbine generators are long and large-scale systems, even if it is known that an abnormality has occurred, it takes a lot of time to find the location and amount of the abnormality. It is necessary. Against this background, as a means of improving the reliability of rotating machines and streamlining maintenance and inspection, it is necessary to detect abnormalities in the rotating shaft early from the vibrations generated in the rotating shaft, and to estimate the location and amount of the abnormality. There is a strong demand for the development of vibration diagnostic technology that can diagnose vibrations in a short time.
In particular, many of the abnormal vibrations that occur in rotating shafts are vibrations that are synchronized with the rotational speed, that is, unbalanced vibrations.Therefore, there is an urgent need to develop diagnostic technology that can estimate the location and amount of unbalance occurrence, which is the source of such unbalanced vibrations. It is becoming. The present inventors have already proposed a method and a device for diagnosing the unbalanced position of unbalanced vibrations in a normal state at a certain rotation speed using data on unbalanced vibrations in an abnormal state. (Japanese Unexamined Patent Publication No. 56-130634) This invention proposes a basic algorithm for diagnosing unbalanced positions, and displays the diagnosed unbalanced positions. However, although there is no particular problem in displaying only the results if the data and conditions necessary for diagnosis are highly accurate, it is expected that the measured data and calculated data will contain some errors. For this reason,
It is also necessary to display the judgment materials necessary for making a diagnosis and leave the decision to the operator. This makes it possible to accurately estimate the amount of unbalance that has occurred. As mentioned above, an object of the present invention is to efficiently diagnose the unbalanced position, which is the source of unbalanced vibration among the abnormal vibrations occurring in rotating machinery such as large turbines, and to improve the smoothness of rotating machinery. The object of the present invention is to provide a vibration diagnosis method and device that enable operation. The feature of the present invention is that when diagnosing the vibration of a rotor by detecting the rotation speed and rotor vibration when the rotor of a rotating machine rotates, unbalance vibrations that are synchronized with the rotation speed are detected from the detected vibration signal. The component is extracted, and the extracted unbalanced vibration component is compared with a reference value indicating allowable vibration to determine whether or not the unbalanced vibration component is abnormal. If it is determined to be abnormal, the unbalanced vibration component is The vibration due to only the abnormality is determined by vector calculation from the balanced vibration component and the pre-stored vibration component during normal rotation, and the vibration pattern of the abnormal component is normalized and determined, and the abnormal vibration pattern is stored in advance. Display unbalanced vibration patterns on the same screen,
To provide a method for diagnosing the position of unbalance occurring in a rotor at a glance and determining the amount of unbalance at this time. Further, the present invention is characterized in that a vibration diagnosis device for a rotating machine is provided with a rotation speed detector for detecting the rotation speed of the rotor, and this rotation speed detector also serves as a phase reference signal. , a vibration detector is provided to detect the vibration of the rotor, a vibration analyzer is provided to extract an unbalanced vibration component synchronized with the rotational speed from this vibration signal and the phase reference signal, and the unbalanced vibration component is abnormal. A determiner is provided for determining whether or not the vibration is abnormal, and a vector calculator is provided for extracting only the abnormal vibration component from the abnormal unbalanced vibration component and the normal vibration previously stored in the storage device when it is abnormal. Furthermore, a computing unit is provided to determine and normalize the maximum value of this abnormal vibration component, and the abnormal vibration pattern from this computing unit and various unbalance patterns previously stored in the pattern storage unit are displayed on the same screen. The present invention is constructed by providing a display device for displaying the information, and further provided with an arithmetic unit for determining the amount of unbalance after diagnosing the unbalance position, and a display device for displaying the result. Hereinafter, an example of implementation of the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to vibration diagnosis in a power generation plant using a turbine. FIG. 1 shows a block diagram of this vibration diagnosis device. In the figure, 1 and 2 are turbine rotors, 3 is a generator rotor, and 41 to 46 are bearings that support each rotor. The present invention is a technology for diagnosing rotor vibration by detecting the rotational speed of the rotors 1, 2, and 3 as shown in the drawings and the journal vibrations in the rotor bearings 41 to 46. A rotation speed detector 5 is provided to detect the rotation speed of the rotor. This rotation speed detector 5 can detect the rotation speed of the rotor when the rotation speed increases or decreases, and in the illustrated example, it is arranged near one bearing 41 of the turbine rotor 1 to detect the rotation speed. It is now being detected. The signal from the rotation speed detector 5 is also used as a phase reference signal a used to analyze the vibration signal and extract an unbalanced vibration component from it. A vibration detector 6 is provided to detect journal vibration of each bearing 41 to 46. In this embodiment, a sensor 61 for detecting rotor vibration is provided in each of the bearings 41 to 46, and a detection signal b from each sensor 61 is input to the vibration detector 6. The vibration signal c from the vibration detector 6 is sent to the vibration analyzer 7, where it is analyzed and an unbalanced vibration component u synchronized with the rotation speed is detected.
is extracted. That is, since the state of vibration differs depending on the number of revolutions, the measured vibration signal c is analyzed based on the number of revolutions and sent to the next determining unit 8. Such an analysis is performed using the phase reference signal a sent from the rotation speed detector 5 and the vibration signal c sent from the vibration detector 6.
This will be done by both. The unbalanced vibration component u analyzed by the vibration analyzer 7 in this manner is sent to the determiner 8, where it is determined whether or not the component u is abnormal. This component u is compared with a predetermined permissible vibration value by the reference signal a, so if it is permissible, it will not be output from the determiner 8, and the determiner will pass through it only if it is abnormal. 8. Therefore, when the unbalanced vibration component u is determined to be abnormal by the determiner 8, the abnormal unbalanced vibration component u' passes through the determiner 8 and enters the vector calculator 10.
That is, when the vibration component u is abnormal, u'=u, and when it is not abnormal, u'=0. The vector calculator 10 is for extracting only the abnormal vibration component v from this abnormal unbalance component u' and the normal vibration. That is, in the abnormal unbalance component u',
Since a component due to normal vibration is also included, the abnormal vibration component v due only to the abnormality is extracted from comparison with the normal vibration. For this reason, it is necessary to clarify the normal vibration U, which is required by the storage device 9.
The normal vibration of each of the bearings 41 to 46 during normal operation is stored in advance, and a signal U of normal vibration is sent from there to the vector calculator 10. In this way, only the abnormal vibration component v due to the unbalance occurring in any of the rotors 1, 2, and 3 is extracted,
Furthermore, this component v is sent to the arithmetic unit 11 that determines the maximum amplitude occurrence position k, and the extracted abnormal vibration component v
The position k indicated by the maximum amplitude is determined. The unbalanced vibration component v is determined by the normalization calculator 12 based on the maximum amplitude occurrence position k determined by the calculator 11.
, where the abnormal vibration component v is normalized with its maximum amplitude. This normalization is necessary in order to compare the following various unbalanced vibration patterns with this abnormal vibration component, and its principle meaning will be described later. The signal normalized by the calculator 12, that is, the abnormal vibration pattern V, is sent to the calculator 14b, where it is compared with various unbalanced vibration patterns p stored in advance. This memorization is carried out in the pattern memory 13, and specifically, in this example, the influence representing the vibration of each bearing journal when a unit unbalance is added to any one point in the axial direction of the rotors 1, 2, and 3. Memorize the coefficient. The influence coefficient pattern p of the pattern memory 13 sent to the arithmetic unit 14b has been normalized through the arithmetic units 11 and 12. Therefore, all the various normalized unbalanced vibration amplitude patterns P and the normalized abnormal signal pattern V are simultaneously displayed on the display 14a. The operator determines the position where the unbalance occurs from the display contents displayed on the display 14a, and inputs the position where the unbalance occurs from the keyboard provided on the display 14a, based on the unbalance amount determination method described later. is calculated and displayed on the display. The configuration of this embodiment is shown in FIG. 2 as a flow diagram. Next, the principle of diagnosing the unbalance position and unbalance amount in the diagnostic technique of this embodiment will be described.
To simplify the explanation below, the following symbols are defined. k: Rotation speed number (k=1, 2,..., K) i: Bearing position number (i=1, 2,..., I) j: Unbalance position number (j=1, 2,..., J) U _i ^(k) : Unbalanced vibration at the k-th rotational speed of the bearing at the i position when it is normal u _i ^(k) : Unbalanced vibration at the k-th rotational speed of the bearing at the i position when it is abnormal v _i ^(k) : Bearing at the i position _{Unbalanced vibration} ^component due ^{only to} unbalance when the _k -th rotation speed of Vibration P _ij ^(k) at bearing i position at k-th rotation speed when adding balance: Normalized p _ij ^(k) (unbalanced vibration pattern) ｜ ｜: Vibration amplitude (the above V _i ^(k) , P _ij ^(k) , the meaning of normalization is to set the maximum amplitude to 1.) The following description will be made using FIGS. 1 and 2. (1) Evaluation method of unbalanced position During the rotor operation indicated by 101, vibration measurement 106 and rotation speed k detection 105 are performed.
Assume that abnormal vibration occurs at the bearing i position at the rotation speed. At this time, the abnormal vibration is detected by sensor 6.
1 and is detected by a vibration detector 6 and input to a vibration analyzer 7. Next, unbalanced vibration analysis
107, in this vibration analyzer 7,
As described above, the vibration signal c from the vibration detector 6 is analyzed with the phase reference signal a from the rotation speed detector 5, and the unbalanced vibration u _i ^(k) is extracted. The determination 108 of unbalanced vibration abnormality is performed by comparing the unbalanced vibration U _i ^(k) with the reference signal a in the determiner 8, and if it is determined to be abnormal, it passes through the determiner 8 and then becomes normal. In order to calculate 110 the vibration difference between each journal vibration during normal and abnormal times, the vector calculator 10 is entered, where v _i ^(k) = u _i ^(k) −U _i ^(k) ...(1) (i =1, 2, ..., I) is performed, and only the abnormal vibration component v _i ^(k) is extracted. In short, by cutting the normal vibration component U _i ^(k) expressed as the normal vibration memory 109 from the vibration component u _i ^(k ) based on unbalance, the vibration component v _i ^(k) of only the abnormality is obtained. It is. The abnormal vibration component v _i ^(k) obtained here is a vector quantity including phase and amplitude information. Next, as shown in 111, in order to determine the maximum amplitude, the arithmetic unit 11 calculates the position k where the abnormal vibration component v _i is maximum.
and its maximum amplitude |v| ^(k) |v|=|v _i ^(k) | _nax ...(2). Furthermore, as shown at 112, in order to normalize the vibration difference with the maximum amplitude, a normalization calculator 1 is used.
2, the following calculation is performed: V _i ^(k) = v _i ^(k) /|v|...(3) (i=1, 2,..., I). As a result, V _i ^(k) is a vector quantity having phase and amplitude information, |V _i ^(k) | _nax =1
This shows a vibration width pattern of (k: const). Therefore, normalization is performed here. On the other hand, as described above, the pattern memory 13 stores various unbalance positions j (j=1, 2, . . .
Influence coefficient when unit imbalance is added to J)
p _ij is memorized. This influence coefficient p _ij ^(k) is also a vector quantity including phase and amplitude information, and the normalized P _ij ^(k) is determined through the calculators 11 and 12, and |P _ij ^(k) | _nax = 1 (i, k: const) and a pattern of vibration and unbalance position. Next, a judgment pattern that serves as a reference for the operator in this embodiment to judge an unbalanced position will be described. First, on the display of the display unit 14a, the horizontal axis is set to the unbalanced position j (j=1, 2,..., J).
and measured unbalance, the vertical axis is the bearing position number i
(i=1, 2, ..., I) is displayed. On this coordinate, the abnormal component vibration amplitude pattern |V _i ^(k) | and the normalized unbalanced vibration amplitude pattern |P _ij ^(k)
By displaying | at the same time, the operator can display |V _i ^(k) and |
Based on the similarity of the pattern with P _ij ^(k) |, the most similar one is identified. Note that in this determination example, only the amplitude is considered when comparing patterns, and phase information is ignored (an example in which phase information is also considered will be described later). Pattern determination in this example is performed as follows. First, focus on the amplitude pattern |V _i ^(k) | of the abnormal vibration, and select the amplitude pattern (1, 2, 3...
Decide on a number to rank each bearing position as shown in I). Next, from the stored unbalanced vibration amplitude pattern |p _ij ^(k) |, for each j, rank each bearing position in descending order of the value (1, 2,..., I) _j . Determine the number. The ranked numbers are displayed on the coordinates on the display. From this display result, the ranking number pattern of the component vibration amplitude pattern and the ranking pattern of the unbalanced vibration amplitude pattern |P _ij ^(k) | are compared and determined, and j having the closest pattern is selected. Therefore, it can be estimated that j is closest to the position where the unbalance occurs in the rotor. Next, the abnormal component vibration amplitude |V _i ^(k) | and,
The following calculation is performed between the normalized unbalance vibration amplitude |P _ij ^(k) | related to each unbalance position. S _i = _I 〓 ^I=1 (｜P _ij ^(k) ｜−｜V _i ^(k) ｜) ² …(4) (j=1, 2,…, J) R _j =√ _j …(5) (j=1, 2,..., J) The calculations of equations (4) and (5) are performed by the calculator 14b,
This corresponds to the calculation of the sum of squares and the root mean square of the sum of squares as shown in 114b. This calculation result is plotted on the horizontal axis as the unbalance occurrence position j (j=1, 2,..., J),
The vertical axis shows S _j and R _j in equation (4) or equation (5) for display device 1.
A bar graph is displayed on the 4a display, but
This corresponds to the monitoring of the unbalanced position indicated as 114a. The size of this bar graph represents the degree of deviation of the memorized and given unbalanced vibration amplitude pattern from the actual abnormal component vibration amplitude, so S _j or
It can be estimated that j for which the value of R _j is as small as possible is closest to the actual position where the unbalance occurs. Therefore, the above two graphs show the above vibration amplitude, the horizontal axis shows the unbalance generator and the actually measured unbalance, and the vertical axis shows the bearing position with numbers indicating the size and the unbalance position determined by similarity. , the operator can determine the unbalance position that has occurred in the rotor from the unbalance position determined by the bar graph of equation (4) or equation (5). Examples of displays for this determination are shown in FIGS. 3 and 4. In Figure 3, UA on the horizontal axis represents the actually measured abnormal component vibration amplitude, and B2 indicates the maximum amplitude.
1 is written at B1, 2 is written at B1, 3 is written at B3, and so on. Further, numbers are similarly written for the unbalanced positions j1, j2, . . . in correspondence with the magnitude of the amplitude. Here, focusing on unbalance position J2, the maximum amplitude position is B2,
This is followed by B1, B3, B4, B6, and B5.
This pattern is exactly the same as the actually measured abnormal component vibration amplitude pattern. The patterns at other unbalance positions j1, j3, ... are all different from the actually measured abnormal component vibration amplitude pattern. From this, it is estimated that the unbalanced position that occurred in the rotor is j2. However, the unbalanced position J3 is relatively similar to the abnormal component vibration amplitude pattern. Therefore, an example of quantitative comparison using equation (4) or equation (5) is shown in FIG. In this figure, the unbalanced position at which the deviation R or S is minimum is j2, followed by j3, j1, j5, and so on. Therefore, it can be inferred that an imbalance has occurred in j2. Therefore, based on these two displays, the operator ultimately determines that there is an extremely high probability that an unbalance has occurred at position j2, and then proceeds to calculate the amount of unbalance that has occurred at this position. . As a result, it is possible to constantly monitor the source of unbalance abnormalities that occur during rotor operation on the display, diagnose the occurrence at the operator's discretion, and subsequently determine the amount of unbalance that has occurred. be. (2) Calculating the amount of unbalance As described above, assume that an unbalance occurs at the unbalance position j2 at the rotational speed k rpm and the abnormality is detected at B2 (that is, the bearing 42). At this time, from the detected abnormal component vibration v _i ^(k) from each bearing 41, 42, ... and the unbalance vibration pattern P _ij ^(k) for which the memory has been given, the unbalance is calculated as shown in the calculation 115 of the unbalance amount. position j2
The amount of unbalance that occurred can be determined. That is, the calculation unit 15 performs the following calculations. Now, let W _j2 be the unbalance amount W _j that has occurred at the unbalance position j2, and this W _j2 is a vector amount having a magnitude and an angle. In addition, in order to obtain W _j2 , the unbalance occurrence position is determined from among the abnormal component vibration v _i ^(k) detected from each bearing 41, 42, ... and the memorized and given unbalance vibration pattern p _ij ^(k). Using the unbalanced vibration pattern p _ij2 ^(k) of j2, the following relational expression holds between them. v _i ^(k) = p _ij2 ^(k) W _j2 …(6) (i=1, 2,…, I) When i=1 in equation (6), the amount of unbalance that occurs is W _j2 = It is determined by v _i ^(k) /p _ij2 ^(k) …(7). On the other hand, when i>1, the unbalance amount W _i2 is not uniquely determined by equation (6). Therefore, we introduce the principle of least squares method. In other words, when an unbalance amount W _j2 occurs at an unbalance position j2 of the rotor, the vibration deviation Δv _i ( ^k ) is calculated for the detected abnormal component vibration v _i ^(k) from each bearing 41, 42,... Assume, then define the evaluation function. At this time, equation (6) becomes v _i ^(k) + Δv _i ^(k) = p _ij2 ^(k) W _j2 ...(8) (i = 1, 2, ..., I), and the evaluation function J is defined as follows. do. J= _I 〓 |Δv _i ^(k) | ² (9) In the end, it is sufficient to find the unbalance amount W _j2 that minimizes the evaluation function J of equation (9). For this purpose, the principle of least squares method is applied. Substituting Equation (8) into Equation (9) and further partial differentiation with respect to W _j2 is made to zero.
As a result, the amount of unbalance is determined by the following formula. W={ ^T p} ^{-1 T} Δv (10) Here, W is the unbalance amount vector, p is the influence coefficient matrix (unbalanced vibration pattern), V is the abnormal vibration vector, and ^T is the Hermite matrix of p as follows. It is expressed as

【formula】

[Formula] W = W _j2 ... (13) As a result, by diagnosing the unbalance position and amount by the above operation, the source of the rotor unbalance abnormality that occurred during operation and the amount of unbalance abnormality or It becomes possible to quickly know the extent of the damage. Note that in the above embodiment, the phase information is ignored,
Although the unbalanced position was diagnosed using only the vibration amplitude pattern, effective diagnosis can also be made by considering phase information. However, in order to use such diagnostic technology, it is necessary not only to normalize the vibration pattern, but also to change the phase using the maximum amplitude as a reference (=0 degrees).
It is necessary to standardize the entire axial position. With respect to this standardized phase, ||90° is considered to be in phase, and 90°<<270° is considered to be out of phase. As a result, the pattern that appeared as shown in FIG. 3 in the above embodiment becomes as shown in FIG. 5. Also, by using V _i ^{(k) for} |V _i (k) | and using P _ij ^(k ) for |P _ij ^(k ) |, we can obtain not only the amplitude pattern but also both phase and amplitude information. Comparisons are made using vector quantities that have . As detailed above, the vibration diagnosis technology for a rotating machine of the present invention can quickly determine abnormal vibrations occurring in a rotating machine and quickly diagnose the unbalanced position, which is the source of the unbalanced vibration. This has the effect of achieving smooth operation of various rotating machines.

[Brief explanation of the drawing]

1 to 5 show an example of the implementation of the present invention, FIG. 1 is a block configuration diagram showing a vibration diagnosis device for a rotating machine, FIG. 2 is a flowchart showing the content of vibration diagnosis, and FIG. 3 and FIG. 4 are graphs showing an example of a vibration pattern for determining the position of occurrence of unbalance, and FIG. 5 is a graph showing an example of an abnormal vibration pattern. 1, 2, 3...Rotor, 41-46...Bearing,
5... Rotation speed detector, 6... Vibration detector, 7...
Vibration analyzer, 8... Judgment device, 9... Storage device, 1
... Vector calculation unit, 11 ... Calculation unit for determining maximum amplitude, 12 ... Calculation unit for normalization, 13 ... Pattern storage device, 15 ... Calculation unit for calculating unbalance amount, 14a, 16... Display unit, 14b...Arithmetic unit.

Claims (1)

[Scope of Claims] 1. A method for diagnosing vibration of a rotating machine, which diagnoses the vibration of a rotor by detecting the rotational speed and vibration of the rotor when the rotor rotates, comprising the following steps. Characteristic vibration diagnosis method for rotating machines. (1) Extracting an unbalanced vibration component synchronized with the rotation speed from the detected rotor vibration signal; (2) Determining that the unbalanced vibration is abnormal based on a comparison between the extracted unbalanced vibration component and its allowable value. (3) If the unbalanced vibration component is determined to be abnormal, the abnormal vibration component is determined from the unbalanced vibration component and the pre-stored rotor vibration component during normal rotation. is determined by vector calculation, and the vibration pattern of this abnormal vibration component is normalized. (5) Calculate the unbalance position of the rotor where the unbalanced vibration that causes the abnormal vibration is occurring by displaying the magnitude relationship of the vibration amplitude on the top so that the magnitude relationship can be seen; (5) Calculate the amount of unbalance that has occurred at the unbalanced position. , is calculated based on the vector-calculated abnormal vibration component and the unbalanced vibration stored in advance. 2. The method for diagnosing a rotating machine according to claim 1, wherein the unbalance amount is calculated using a previously stored influence coefficient of unbalance vibration. 3. In a vibration diagnosis device for a rotating machine that diagnoses the vibration of a rotor by detecting the rotation speed and rotor vibration when the rotor rotates, a rotation speed detector that detects the rotation speed of the rotor, an arbitrary A vibration detector detects rotor vibration occurring in the rotor based on the position, and an unbalanced vibration component synchronized with the rotation speed is extracted from the vibration signal from the vibration detector and the phase reference signal obtained from the rotation speed detector. A vibration analyzer, a determination device that compares the unbalanced vibration component extracted from the vibration analyzer with a reference value to determine whether the unbalanced vibration component is abnormal, and a storage device that stores in advance rotor vibration components in normal conditions. , a first arithmetic unit that extracts an abnormal vibration component from the abnormal unbalanced vibration component from the determination device and the stored normal vibration component from the storage device; a second arithmetic unit that determines the maximum amplitude; a third arithmetic unit that normalizes the abnormal vibration component based on the maximum amplitude of the abnormal vibration component from the second arithmetic unit; and a pattern of unbalanced vibration that is stored in advance. A pattern storage device that stores the normalized abnormal vibration pattern that has passed through the third arithmetic unit and the unbalanced vibration pattern that has also been normalized from the pattern storage device so that the magnitude of the vibration amplitude can be seen. A display that displays on the screen, the amount of unbalance at the unbalance position diagnosed based on this display, the abnormal vibration component that has passed through the first computing unit, and the pre-stored unbalance from the pattern memory. Vibration diagnosis of a rotating machine characterized by comprising a fourth calculator that calculates the unbalance amount of the abnormal vibration occurring at the unbalanced position based on the balanced vibration, and a display that displays the result. Device.