JP7356267B2 - Anomaly detection device, anomaly detection method and program - Google Patents

Description

The present invention relates to an abnormality detection device, an abnormality detection method, and a program.

When a steam turbine is operated for a long period of time, the control valve may become stuck due to deposits such as scale, making it impossible to fully close it. Since the control valve is a closed space, it is difficult to inspect the accumulation of deposits during operation of the steam turbine plant. Therefore, the occurrence of an abnormality cannot be detected early, and measures such as forced shutdown of the plant may be required after an abnormality occurs.
For example, Patent Document 1 discloses a method of detecting the open/closed state of a valve using a magnetic sensor and detecting signs of abnormality of the valve based on the time from the closed state to the open state of the valve.

Japanese Patent Application Publication No. 2018-55636

For example, in plants, there is a need for a method for early detection of valve malfunctions while the plant is operating. Note that although a magnetic sensor is used in the method described in Patent Document 1, it is not suitable because the operating environment of the plant is high temperature.

Therefore, an object of the present invention is to provide an abnormality detection device, an abnormality detection method, and a program that can solve the above-mentioned problems.

According to one aspect of the present invention, an abnormality detection device includes an analysis section that analyzes vibration characteristics of vibration data detected when fluid passes through a valve of a steam turbine, and an analysis section that analyzes vibration characteristics of vibration data of the valve in a normal state. a first normal database storing permissible ranges for each valve opening degree of the valve, flow rate and temperature of steam passing through the valve; and a permissible range of vibration characteristics of the valve in a normal state; a second normal database stored for each operating status of the steam turbine; and an operating data acquisition unit that acquires information on the opening degree of the valve, the flow rate , and the temperature , or the operating status of the steam turbine; Based on the information acquired by the operation data acquisition unit, a permissible range of vibration characteristics of the valve in a normal state is set with reference to the first normal database or the second normal database. a range setting unit, a determination for detecting a sign of abnormality in the valve based on the vibration characteristics analyzed by the analysis unit, and an allowable range of the vibration characteristics in a normal state of the valve set by the tolerance range setting unit; When the operation data acquisition unit acquires the opening degree, the flow rate, and the temperature of the valve, the tolerance setting unit includes a Based on the temperature, an allowable range of vibration characteristics of the valve in a normal state is set with reference to the first normal state database, and the operation data acquisition unit obtains information on the operating status of the steam turbine. In this case, an allowable range of vibration characteristics of the valve in a normal state is set by referring to the second normal state database based on the obtained information on the operating status of the steam turbine.

According to one aspect of the present invention, the operating status is the magnitude of the load on the steam turbine, or the time required for a change in the load on the steam turbine and the magnitude of the change.

According to one aspect of the present invention, the vibration characteristic is a peak frequency of a spectrum obtained by frequency analyzing the vibration data.

According to one aspect of the present invention, the vibration characteristic is a damping ratio of a peak in a spectrum obtained by frequency analysis of the vibration data.

According to one aspect of the present invention, the vibration characteristic is a peak value of a spectrum obtained by frequency analysis of the vibration data.

According to one aspect of the present invention, the vibration characteristic is time-series waveform data of the vibration data.

According to one aspect of the present invention, the property of the fluid is the temperature of the fluid.

According to one aspect of the invention, the valve includes a valve stem, and the vibration data is vibration of the valve stem.

According to one aspect of the present invention, the abnormality detection device further includes a sensor that detects vibrations attached to the valve stem or a member integrally formed with the valve stem.

According to one aspect of the present invention, the abnormality detection device further includes an output unit that notifies the valve that there is a sign of sticking when the determination unit detects a sign of abnormality.

According to one aspect of the present invention, an abnormality detection method includes the steps of analyzing vibration characteristics of vibration data detected when fluid passes through a valve of a steam turbine; A step of acquiring information on the flow rate and temperature of steam or the operating status of the steam turbine , and when the opening degree of the valve, the flow rate, and the temperature are acquired in the acquiring step, the acquired Based on the opening degree of the valve, the flow rate, and the temperature, an allowable range of vibration characteristics in a normal state of the valve is stored for each valve opening degree of the valve, and the flow rate and temperature of steam passing through the valve. When information on the operating status of the steam turbine is acquired in the step of setting an allowable range of vibration characteristics of the valve in a normal state with reference to a first normal database, the information on the operating status of the steam turbine is acquired. Based on the information on the operating status of the steam turbine, the second normal database stores the permissible range of vibration characteristics of the valve in a normal state for each operating status of the steam turbine. a step of setting a permissible range of vibration characteristics in a normal state of the valve ; the vibration characteristics analyzed in the analyzing step; and a permissible range of vibration characteristics in a normal state of the valve set in the setting step; and detecting a sign of abnormality in the valve based on.

According to one aspect of the present invention, a program causes a computer to analyze vibration characteristics of vibration data detected when fluid passes through a valve of a steam turbine; a step of acquiring information on the flow rate and temperature of steam to be used, or information on the operating status of the steam turbine , and when the opening degree of the valve, the flow rate, and the temperature are acquired in the acquiring step, the acquired Based on the opening degree of the valve, the flow rate, and the temperature, an allowable range of vibration characteristics in a normal state of the valve is stored for each valve opening degree of the valve, and the flow rate and temperature of steam passing through the valve. When information on the operating status of the steam turbine is acquired in the step of setting an allowable range of vibration characteristics of the valve in a normal state with reference to a first normal database, the information on the operating status of the steam turbine is acquired. Based on the information on the operating status of the steam turbine, the second normal database stores the permissible range of vibration characteristics of the valve in a normal state for each operating status of the steam turbine. a step of setting a permissible range of vibration characteristics in a normal state of the valve ; the vibration characteristics analyzed in the analyzing step; and a permissible range of vibration characteristics in a normal state of the valve set in the setting step; and detecting a sign of abnormality in the valve based on the above.

According to the present invention, it is possible to detect signs of valve abnormality.

1 is a schematic system diagram of a power plant equipped with a steam turbine to which a steam valve device according to an embodiment of the present invention is applied. 1 is a schematic cross-sectional view of a steam valve device according to an embodiment of the present invention. FIG. 1 is a block diagram of an abnormality detection device according to an embodiment of the present invention. FIG. 1 is a first diagram illustrating a determination method according to an embodiment of the present invention. It is a figure explaining an example of the calculation method of the damping ratio concerning one embodiment of the present invention. FIG. 2 is a second diagram illustrating a determination method according to an embodiment of the present invention. FIG. 3 is a first diagram showing an example of an allowable range depending on driving conditions according to an embodiment of the present invention. FIG. 6 is a second diagram illustrating an example of an allowable range depending on driving conditions according to an embodiment of the present invention. 3 is a flowchart illustrating an example of abnormality detection processing according to an embodiment of the present invention. 1 is a diagram showing an example of a hardware configuration of an abnormality detection device according to an embodiment of the present invention.

<Embodiment>
Hereinafter, a method for predicting a valve abnormality according to each embodiment of the present invention will be described with reference to FIGS. 1 to 10.
FIG. 1 is a schematic system diagram of a power plant equipped with a steam turbine to which a steam valve device according to each embodiment of the present invention is applied. FIG. 2 is a schematic cross-sectional view of a steam valve device according to an embodiment of the present invention.
The power generation system 30 includes a steam turbine 31 including a high-pressure steam turbine 32, an intermediate-pressure steam turbine 33, and a low-pressure steam turbine 34, a boiler 35 that supplies high-pressure steam to the high-pressure steam turbine 32, and steam discharged from the high-pressure steam turbine 32. It is comprised of a reheater 36 that reheats steam and supplies it to the intermediate pressure steam turbine 33, and a generator 37 driven by the rotational driving force of the steam turbine 31.

In addition, a main steam stop valve 2 (MSV) and a steam control valve 3 (GV) are provided in the piping connecting the boiler 35 and the high-pressure steam turbine 32, and are mainly used to supply steam to the high-pressure steam turbine. This is prevented by fully closing the steam stop valve 2, or the supply flow rate of steam is controlled by the steam control valve 3. A similar main steam stop valve 40 and steam control valve 41 are also provided in piping connecting the reheater 36 and the intermediate pressure steam turbine 33.
A steam valve device 1 according to an embodiment of the present invention includes, for example, the main steam stop valve 2 of the steam turbine 31 and the steam control valve 3 as described above. As shown in the figure, an abnormality detection device 100 is provided for the steam valve device 1. The abnormality detection device 100 detects signs of abnormality in the main steam stop valve 2 and the steam control valve 3.

As shown in FIG. 2, the steam valve device 1 includes a main steam stop valve 2 that shuts off steam flowing into the steam turbine, and a steam control valve 3 that controls the steam flow rate according to the steam turbine load. It is constructed integrally with the intervening. After the main steam stop valve 2 is fully opened, the steam control valve 3 is opened and closed to control the flow rate of steam passing through the steam valve device 1, and the steam turbine is operated in accordance with the load. ing.

The main steam stop valve 2 is composed of a valve case 6 containing a valve body 5, a valve shaft 7 that slidably drives the valve body 5, and a bush 8 that supports the valve shaft 7. Further, the upper part of the valve case 6 is sealed by an upper cover 9, and the valve shaft 7 passes through the approximate center of the upper cover 9.

The steam control valve 3 is arranged downstream of the main steam stop valve 2 via the communication passage 4. The steam control valve 3 is composed of a valve case 11 containing a valve body 10, a valve shaft 12 that slidably drives the valve body 10, and a bush 13 that supports the valve shaft 12. Further, the upper part of the valve case 11 is sealed by an upper lid 14, and the valve shaft 12 passes through approximately the center of the upper lid 14.

Steam flowing from the boiler 35 of the power generation system 30 shown in FIG. The valve body 5 flows between the seat surface 18 of the valve body in contact with the valve seat 17 and the valve seat 17, and is sent to the steam control valve 3 via the communication passage 4.

Thereafter, the steam sent to the steam control valve 3 is controlled by moving the valve body 10 forward and backward with respect to the valve seat 19, and the valve body 10 and the seat surface 20 of the valve body in contact with the valve seat 19 and the valve seat 19 and flows from the mainstream steam outlet pipe 22 to the steam turbine via the second mainstream steam passage 21.

The main steam stop valve 2 is used to shut off steam flowing into the turbine in an emergency or an emergency, or to shut off steam when the turbine is shut down. The steam control valve 3 gently increases and decreases the steam flow rate during normal startup and shutdown, and adjusts the flow rate in accordance with load fluctuations.

This embodiment provides a method for detecting signs of abnormality in the main steam stop valve 2 and the steam control valve 3. In the following, a method for detecting a sign of abnormality in the steam control valve 3 will be explained as an example, but a similar method can be used to detect a sign of abnormality in the main steam stop valve 2. Further, by using a similar method, it is possible to detect signs of abnormality in the main steam stop valve 40 and the steam control valve 41 shown in FIG.

When the steam turbine 31 is operated, for example, scale (water scale) adheres to the valve shaft 12 of the steam control valve 3, and the sliding range of the valve body 10 becomes limited. Then, the steam control valve 3 cannot be fully closed.

When scale adheres to the valve stem 12, the vibration characteristics of the valve stem 12 change. In this embodiment, a sensor is attached to the valve stem 12 and the bush 13 that is integrally formed with the valve stem 12 to detect vibrations of the valve stem 12. Further, since high temperature and high pressure fluid (steam) flows through the steam control valve 3, it is difficult to attach a sensor inside the valve. Even if the sensor could be installed, the sensor would be damaged and if it flowed into the piping, it would damage the turbine blades. Therefore, a sensor is attached to a part of the steam control valve 3 that is exposed to the outside and can detect vibrations of the valve shaft 12. Then, an abnormality in the steam control valve 3 is predicted based on changes in the vibration characteristics of the valve stem 12.

For example, the valve shaft 12 is provided with a sensor 23 that detects vibrations of the valve shaft 12. The bush 13 is provided with a sensor 24 that detects vibrations of the valve shaft 12 via the bush 13. The sensors 23 and 24 are, for example, an acceleration sensor, an eddy current displacement sensor, a laser displacement sensor, or the like. The sensors 23 and 24 are connected to the abnormality detection device 100. The vibration data detected by the sensors 23 and 24 is transmitted to the abnormality detection device 100. Note that it is not necessary to provide both of these sensors, and only one of them may be provided. The sensor may be attached to the valve stem 12 or to a member integrally connected to the valve stem 12 (bush 13), but a position where the vibration of the valve stem 12 can be detected more accurately (for example, sensor 23) is preferable.
In the following description, an example will be described in which a sign of abnormality in the steam control valve 3 is detected based on vibration data detected by the sensor 23.

FIG. 3 is a block diagram of an abnormality detection device according to an embodiment of the present invention.
As shown in the figure, the abnormality detection device 100 includes a vibration data analysis section 101, an operation data acquisition section 102, a normal database 103, an allowable range setting section 104, a determination section 105, and an output section 106. .

The vibration data analysis unit 101 acquires vibration data detected by the sensor 23 and performs frequency analysis and the like. For example, the vibration data analysis unit 101 analyzes vibration data, acquires a frequency spectrum, and calculates the peak frequency (natural frequency of the valve shaft 12), its peak value, and the damping ratio of the peak (for example, the peak frequency and the peak Calculated from the ratio of half-width.)
The operation data acquisition unit 102 acquires values detected by various sensors provided in the steam turbine 31, control values, and the like. For example, the operation data acquisition unit 102 acquires information such as the valve opening degree of the steam control valve 3, the flow rate and temperature of steam passing through the steam control valve 3.

The normal state database 103 stores the vibration characteristics of the valve shaft 12 and its allowable range in the normal state of the steam control valve 3 for each operating condition of the steam turbine 31. For example, the normal state database 103 stores the range of normal vibration characteristics of the valve stem 12 in association with the valve opening degree of the steam control valve 3 and the flow rate and temperature of steam passing through the steam control valve 3. This value may be based on data actually measured in the past, or may be obtained by analysis using a theoretical calculation. Further, the range of normal vibration characteristics may be newly updated as the steam turbine 31 operates.

The allowable range setting unit 104 determines the normal vibration characteristic range (tolerable range) of the valve shaft 12 according to the operating status of the steam turbine 31 based on the operating data acquired by the operating data acquiring unit 102 in the normal state database 103. Refer to and set. The operating status of the steam turbine 31 can be determined based on, for example, the valve opening degree, the steam flow rate, and the temperature.
Further, the allowable range setting unit 104 may set the allowable range based on, for example, the load band of the steam turbine 31 or changes in the load.

The determination unit 105 compares the vibration characteristics of the valve stem 12 analyzed by the vibration data analysis unit 101 with the tolerance range set by the tolerance range setting unit 104, and determines whether the vibration characteristics are within the tolerance range. . If the vibration characteristics are within the allowable range, the determination unit 105 determines that the steam control valve 3 is normal; if it is outside the allowable range, the determination unit 105 determines that there is a sign of an abnormality in the steam control valve 3.

The output unit 106 outputs the determination result by the determination unit 105. For example, the output unit 106 displays "normal" or "abnormality sign present" on a monitor monitored by an operator.

FIG. 4 is a first diagram illustrating a determination method according to an embodiment of the present invention.
The analysis data 401 is a spectrum obtained as a result of frequency analysis of vibration data (acceleration waveform data) detected by the sensor 23 or the like before scale is attached to the valve stem 12 (normal state). The analysis data 402 is a spectrum obtained as a result of frequency analysis of vibration data detected by the sensor 23 or the like after scale has adhered to the valve stem 12 (at the time of abnormality). Alternatively, the analytical data 401 and 402 may be obtained by desk calculation based on a physical model of the steam control valve 3. As shown in the figure, the peak frequencies of analysis data 401 and analysis data 402 are different. This is because the vibration characteristics of the valve shaft 12 have changed due to the adhesion of scale. If the difference between the peak frequency of the analysis data 401 and the peak frequency of the analysis data 402 analyzed by the vibration data analysis unit 101 is greater than or equal to a predetermined threshold, the determination unit 105 determines that there is a sign of abnormality in the steam control valve 3. In the normal state database 103, for example, a peak frequency during normal state and an allowable range for the peak frequency are set.

Further, as shown in the figure, the attenuation ratios of the peaks found by analyzing the analysis data 401 and the analysis data 402 are different. The difference in damping ratio is also considered to be caused by a change in the vibration characteristics of the valve shaft 12 due to the adhesion of scale. If the difference between the damping ratio of the analysis data 401 and the damping ratio of the analysis data 402 analyzed by the vibration data analysis unit 101 is equal to or greater than a predetermined threshold, the determination unit 105 determines that there is a sign of abnormality in the steam control valve 3. In the normal state database 103, for example, a normal damping ratio and an allowable range for the damping ratio are set.

Here, FIG. 5 shows an example of a method for calculating the peak damping ratio. As shown in FIG. 5, the peak attenuation ratio is the half-width Δf, which is the spectrum width at the position where the magnitude is the peak value x (1 ÷ (square root of 2)) with respect to the peak value on both sides of the target spectrum peak. If the peak frequency is f, it can be determined by the following formula.
Damping ratio = Δf÷2f
Note that the damping ratio is not limited to this method, and may be calculated using other known methods.

Return to Figure 4. As shown in the figure, the peak values of analysis data 401 and analysis data 402 are different. The difference in peak values is also considered to be caused by a change in the vibration characteristics of the valve shaft 12 due to the adhesion of scale. If the difference between the peak value of the analysis data 401 and the peak value of the analysis data 402 analyzed by the vibration data analysis unit 101 is greater than or equal to a predetermined threshold, the determination unit 105 determines that there is a sign of abnormality in the steam control valve 3. In the normal state database 103, for example, a peak value during normal state and an allowable range for the peak value are set.

FIG. 6 is a second diagram illustrating a determination method according to an embodiment of the present invention.
Vibration data 601 is vibration data (time-series changes in acceleration) detected by the sensor 23 and the like before scale is attached to the valve stem 12 (normal state). Vibration data 602 is vibration data detected by the sensor 23 or the like after scale has adhered to the valve stem 12 (at the time of abnormality). Alternatively, the vibration data 601 and 602 may be obtained by desk calculation based on a physical model of the steam control valve 3. The determining unit 105 may determine whether the vibration data 602 is normal by comparing the waveforms (amplitude and frequency) of the vibration data 601 and the vibration data 602. Alternatively, the determination unit 105 may determine whether the vibration data 602 is normal by calculating a correlation coefficient between the vibration data 601 and the vibration data 602.

FIG. 7 is a first diagram showing an example of an allowable range depending on driving conditions according to an embodiment of the present invention.
For example, when the steam turbine 31 is operating with a constant load, the information such as the valve opening degree, flow rate, and temperature acquired by the operation data acquisition unit 102 is also constant. The allowable range setting unit 104 refers to the normal state database 103 and obtains an allowable range of frequency analysis data corresponding to a certain combination of valve opening, flow rate, and temperature. A threshold value 701 and a threshold value 702 shown in FIG. 7 are the upper limit value and lower limit value of the tolerance range set by the tolerance range setting unit 104, respectively. The black dots in FIG. 7 are frequency analysis data analyzed by the vibration data analysis unit 101. If the frequency analysis data analyzed by the vibration data analysis unit 101 is within the allowable range, the determination unit 105 determines that scale accumulation on the steam control valve 3 has not progressed and is in a normal state. . On the other hand, if the frequency analysis data falls outside the allowable range, it is determined that scale accumulation on the steam control valve 3 is progressing (there is a sign of abnormality). The criteria by which the determining unit 105 determines that something is abnormal can be set arbitrarily. For example, the determination unit 105 may determine that there is a sign of an abnormality when the frequency analysis data falls outside the allowable range a predetermined number of times or more in a row, or determines that there is a sign of an abnormality when the frequency analysis data falls outside the allowable range a predetermined number of times or more in a predetermined period. If it is outside, it may be determined that there is a sign of an abnormality.

Further, for example, an allowable range may be set in the normal state database 103 in association with the magnitude of the load on the steam turbine 31. The allowable range setting unit 104 may acquire the threshold value 701 and the threshold value 702 from the normal state database 103 based on the load of the steam turbine 31 acquired by the operation data acquisition unit 102.

FIG. 8 is a second diagram illustrating an example of an allowable range depending on driving conditions according to an embodiment of the present invention.
When the load on the steam turbine 31 fluctuates, the information acquired by the operation data acquisition unit 102, such as the valve opening degree, flow rate, and temperature, also fluctuates. For example, when the load increases, the opening degree of the steam control valve 3 and the flow rate of steam also increase, and the temperature also changes. When the opening degree, flow rate, or temperature changes, the vibration characteristics (peak frequency, damping ratio, peak value) of the valve shaft 12 change. Therefore, it is necessary to determine whether the vibration characteristic data analyzed by the vibration data analysis unit 101 is normal or abnormal, based on a threshold value that corresponds to a change in the opening degree or the like.

For example, the allowable range setting unit 104 acquires information such as the latest valve opening degree from the operation data acquisition unit 102 from time to time, and refers to the normal state database 103 each time to determine the current valve opening degree and flow rate. , obtain the tolerance range of frequency analysis data corresponding to the temperature combination. A threshold value 801 and a threshold value 802 shown in FIG. 8 are an upper limit value and a lower limit value, respectively, of the allowable range set by the allowable range setting unit 104 according to fluctuations in the driving situation. As in the case of FIG. 7, if the frequency analysis data analyzed by the vibration data analysis unit 101 falls within the permissible range, the determination unit 105 determines that the steam control valve 3 is in a normal state, and If it is outside the range, it is determined that there is a sign of abnormality in the steam control valve 3.

Note that the operation data acquisition unit 102 may acquire control values representing the magnitude and amount of change in the load of the steam turbine 31 in addition to the valve opening degree and the like. In addition, the normal state database 103 includes, for example, the allowable range of the normal vibration characteristics of the valve stem 12 when changing the load from X1 to X2 over a predetermined period of time (for example, the allowable range of section B in FIG. 8). It may be registered. Then, the allowable range setting unit 104 determines that the load of the steam turbine 31 will change from X1 to X2 over a predetermined period of time based on the control value acquired by the operation data acquisition unit 102, and determines that the load of the steam turbine 31 will change from X1 to X2 over a predetermined period of time. Obtain the permissible range according to the driving situation. By such processing, if fluctuations in the operating status of the steam turbine 31 can be predicted in advance, there is no need to set tolerance ranges based on valve opening, flow rate, and temperature from time to time, and it is possible to predict tolerances up to a predetermined time ahead. A range can be set.

Next, the flow of the abnormality sign processing will be explained using FIG. 9.
FIG. 9 is a flowchart illustrating an example of abnormality detection processing according to an embodiment of the present invention.
The following process is repeatedly performed at a predetermined control cycle, for example.
First, the operation data acquisition unit 102 acquires the valve opening degree of the steam control valve 3, the flow rate and temperature of steam passing through the steam control valve 3 (step S101). The driving data acquisition unit 102 outputs this information to the allowable range setting unit 104. Next, the allowable range setting unit 104 refers to the normal state database 103 and obtains the normal range of the vibration characteristics of the valve shaft 12 corresponding to the valve opening degree, flow rate, and temperature obtained by the operation data obtaining unit 102. This range is set as an allowable range (step S102). The set tolerance range is at least one of a peak frequency tolerance range, a peak damping ratio tolerance range, and a peak value tolerance range depending on the operating status of the steam turbine 31. The allowable range setting section 104 outputs the set value of the allowable range to the determining section 105.

In parallel with step S101, the vibration data analysis unit 101 acquires vibration data from the sensor 23 (step S103). Next, the vibration data analysis unit 101 calculates vibration characteristics from the acquired vibration data (step S104). For example, the vibration data analysis unit 101 performs frequency analysis on vibration data and calculates at least one of a peak frequency, a peak damping ratio, and a peak value. The vibration data analysis unit 101 outputs the calculated vibration characteristics to the determination unit 105.

Next, the determination unit 105 determines whether the vibration characteristics calculated by the vibration data analysis unit 101 are within a set tolerance range (step S105). The determining unit 105 determines that the vibration characteristic is normal if it is within the permissible range (step S106), and determines that there is a sign of abnormality if the vibration characteristic is outside the permissible range (step S107).

For example, the determination unit 105 determines that the vibration data is normal if the peak frequency calculated by the vibration data analysis unit 101 is within the allowable range of peak frequencies. Further, the determining unit 105 determines that the peak damping ratio calculated by the vibration data analyzing unit 101 is normal if it is within the allowable range of the peak damping ratio. Further, the determining unit 105 determines that the peak value calculated by the vibration data analyzing unit 101 is normal if it is within the allowable range of the peak value. Alternatively, when determining using both the peak frequency and the peak damping ratio, the determining unit 105 determines that the calculated peak frequency and peak damping ratio are normal if either the calculated peak frequency or the peak damping ratio is within the allowable range, and that both are normal. If it is outside the allowable range, it may be determined that there is a sign of abnormality. For example, when making a determination using all of the peak frequency, peak attenuation ratio, and peak value, the determination unit 105 determines that two or more of the calculated peak frequency, peak attenuation ratio, and peak value are within the allowable range. If two or more of them are outside the allowable range, it may be determined that there is a sign of abnormality.

The determination unit 105 outputs the determination result to the output unit 106. The output unit 106 notifies the monitoring staff or the like of the determination result (step S108). For example, the output unit 106 displays text such as "normal", "sign of abnormality", "sign of valve stem sticking", etc. on the monitor. Alternatively, the output unit 106 may send the determination result to the person concerned by e-mail or the like.

In this embodiment, the vibration of the structure of the valve (the structure that vibrates due to the flow of fluid and to which scale adheres) is a phenomenon in which deposits such as scale accumulate inside the valve and the gap through which fluid passes becomes smaller. Detected by changes in characteristics.

Specifically, vibration characteristics (peak frequency, peak damping ratio) are determined by frequency analysis of vibration data (vibration data of valve stem 12) detected when fluid (steam) passes through a valve (steam control valve 3). , peak value). Then, abnormality sign detection is performed by comparing this vibration characteristic with the permissible range of the vibration characteristic in the normal state of the valve.
Thereby, for example, sticking of the valve stem (valve shaft 12) can be predicted. In addition, it is possible to plan in advance the inspection and maintenance of a valve in which an abnormality has been detected when the valve is scheduled to be shut down, such as during periodic inspection.

Note that the permissible range of the vibration characteristics in the normal state can be arbitrarily set depending on the timing of the abnormal sign (how far in advance should it be detected), how much error is allowed, etc. For example, if the difference in peak frequency between normal and abnormal times is 10 Hz, the permissible deviation range from normal times can be set to ±5 Hz.

Furthermore, as the opening degree, fluid flow rate, and properties change, the force exerted by the fluid on the valve when the fluid passes through the valve changes, and the vibration characteristics of the valve structure change. Therefore, the threshold value of the vibration characteristic is registered in association with the opening degree of the valve, the flow rate of the fluid, and the properties of the fluid. This makes it possible to make a determination based on a threshold value depending on the situation, and it is possible to improve the accuracy of abnormality signs. Note that the characteristics of the fluid include, for example, the temperature, viscosity, and pressure of the fluid.

In addition, if the target valve is the steam control valve 3 of the steam turbine 31, the vibration characteristics during normal operation may be determined depending on the operating status of the steam turbine 31 (during low load operation, high load operation, load fluctuation, etc.). An abnormality sign may be detected using a threshold value that corresponds to the operating status of the steam turbine 31 in advance.

FIG. 10 is a diagram showing an example of the hardware configuration of an abnormality detection device according to an embodiment of the present invention.
The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input/output interface 904, and a communication interface 905.
The above-described abnormality detection device 100 is implemented in a computer 900. Each of the above-mentioned functions is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, expands it to the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 reserves a storage area in the main storage device 902 according to the program. Further, the CPU 901 secures a storage area in the auxiliary storage device 903 to store the data being processed according to the program.

A program for realizing all or part of the functions of the abnormality detection device 100 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed, thereby achieving each function. The processing may be performed by the department. Note that the "computer system" herein includes hardware such as an OS and peripheral devices. Furthermore, the term "computer system" includes the homepage providing environment (or display environment) if a WWW system is used. Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, and storage devices such as hard disks built into computer systems. Further, when this program is distributed to the computer 900 via a communication line, the computer 900 that received the distribution may develop the program in the main storage device 902 and execute the above processing. Further, the above program may be one for realizing a part of the above-mentioned functions, and further may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. . Further, the abnormality detection device 100 may be configured by a plurality of computers 900.

In addition, it is possible to appropriately replace the components in the above-described embodiments with well-known components without departing from the spirit of the present invention. Further, the technical scope of the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit of the present invention.
Note that the main steam stop valve 2, the steam control valve 3, the main steam stop valve 40, and the steam control valve 41 are examples of main valves of the steam turbine.

DESCRIPTION OF SYMBOLS 1...Steam valve device, 2...Main steam stop valve, 3...Steam control valve, 4...Communication passage, 5...Valve body, 6...Valve case, 7... Valve stem, 8...Bush, 9...Top cover, 10...Valve body, 11...Valve case, 12...Valve stem, 13...Bush, 14...Top cover, 15... Mainstream steam inlet pipe, 16... First mainstream steam passage, 17... Valve seat, 18... Seat surface, 19... Valve seat, 20... Seat surface, 21... No. Two main stream steam passages, 22... Main stream steam outlet pipe, 23... Sensor, 24... Sensor, 30... Power generation system, 31... Steam turbine, 32... High pressure steam turbine, 33... ... Medium pressure steam turbine, 34 ... Low pressure steam turbine, 35 ... Boiler, 36 ... Reheater, 37 ... Generator, 40 ... Main steam stop valve, 41 ... Steam Adjustment valve, 100... Abnormality detection device, 101... Vibration data analysis section, 102... Operation data acquisition section, 103... Normal time database, 104... Tolerance range setting section, 105... Judgment unit, 106... Output unit, 900... Computer, 901... CPU, 902... Main storage device, 903... Auxiliary storage device, 904... Input/output interface, 905... communication interface

Claims (12)

an analysis unit that analyzes vibration characteristics of vibration data detected when fluid passes through a valve of a steam turbine;
a first normal database storing an allowable range of vibration characteristics of the valve in a normal state for each valve opening degree of the valve, flow rate and temperature of steam passing through the valve;
a second normal database storing a permissible range of vibration characteristics of the valve in a normal state for each operating condition of the steam turbine;
an operation data acquisition unit that acquires information on the opening degree of the valve, the flow rate and the temperature , or the operation status of the steam turbine;
Based on the information acquired by the operation data acquisition unit, a permissible range of vibration characteristics of the valve in a normal state is set with reference to the first normal database or the second normal database. A range setting section;
a determination unit that detects a sign of abnormality in the valve based on the vibration characteristics analyzed by the analysis unit and an allowable range of vibration characteristics in a normal state of the valve set by the tolerance setting unit;
Equipped with
When the operation data acquisition unit acquires the opening degree, the flow rate, and the temperature of the valve, the allowable range setting unit determines the opening degree, the flow rate, and the temperature of the valve based on the acquired opening degree, the flow rate, and the temperature. setting a permissible range of vibration characteristics of the valve in a normal state with reference to a first normal state database;
When the operation data acquisition unit acquires the information on the operation status of the steam turbine, it refers to the second normal database based on the acquired information on the operation status of the steam turbine, and determines the operation status of the valve. Setting the permissible range of vibration characteristics under normal conditions,
Anomaly detection device. The operating status is the magnitude of the load on the steam turbine, or the time required for a change in the load on the steam turbine and the magnitude of the change,
The abnormality detection device according to claim 1. The vibration characteristic is a peak frequency of a spectrum obtained by frequency analysis of the vibration data,
An abnormality detection device according to any one of claims 1 to 2. The vibration characteristic is a damping ratio of a spectrum peak obtained by frequency analysis of the vibration data.
The abnormality detection device according to any one of claims 1 to 3. The vibration characteristic is a peak value of a spectrum obtained by frequency analysis of the vibration data.
The abnormality detection device according to any one of claims 1 to 4. The vibration characteristic is a time-series waveform of the vibration data,
The abnormality detection device according to any one of claims 1 to 5. The property of the fluid is the temperature of the fluid,
The abnormality detection device according to any one of claims 1 to 6. The valve includes a valve stem, and the vibration data is vibration of the valve stem.
The abnormality detection device according to any one of claims 1 to 7. a sensor for detecting vibrations attached to the valve stem or a member integrally formed with the valve stem;
The abnormality detection device according to claim 8, further comprising: an output unit that notifies the valve that there is a sign of sticking when the determination unit detects a sign of abnormality;
The abnormality detection device according to any one of claims 1 to 9, further comprising: analyzing the vibration characteristics of the vibration data detected as the fluid passes through the valves of the steam turbine;
acquiring information on the opening degree of the valve , the flow rate and temperature of steam passing through the valve , or the operating status of the steam turbine;
When the opening degree, the flow rate, and the temperature of the valve are acquired in the acquiring step, based on the acquired opening degree, the flow rate, and the temperature of the valve, the vibration in the normal state of the valve is determined. Tolerance of vibration characteristics of the valve under normal conditions is determined by referring to a first normal database that stores permissible ranges of characteristics for each valve opening degree of the valve and the flow rate and temperature of steam passing through the valve. When information on the operating status of the steam turbine is acquired in the step of setting a range and acquiring the range, vibration characteristics of the valve in a normal state are determined based on the acquired information on the operating status of the steam turbine. setting a permissible range of vibration characteristics of the valve in a normal state by referring to a second normal database storing permissible ranges for each operating status of the steam turbine;
Detecting an abnormality sign of the valve based on the vibration characteristics analyzed in the analyzing step and the permissible range of vibration characteristics in a normal state of the valve set in the setting step;
An anomaly detection method having to the computer,
analyzing the vibration characteristics of the vibration data detected as the fluid passes through the valves of the steam turbine;
acquiring information on the opening degree of the valve , the flow rate and temperature of steam passing through the valve , or the operating status of the steam turbine;
When the opening degree, the flow rate, and the temperature of the valve are acquired in the acquiring step, based on the acquired opening degree, the flow rate, and the temperature of the valve, the vibration in the normal state of the valve is determined. Tolerance of vibration characteristics of the valve under normal conditions is determined by referring to a first normal database that stores permissible ranges of characteristics for each valve opening degree of the valve and the flow rate and temperature of steam passing through the valve. When information on the operating status of the steam turbine is acquired in the step of setting a range and acquiring the range, vibration characteristics of the valve in a normal state are determined based on the acquired information on the operating status of the steam turbine. setting a permissible range of vibration characteristics of the valve in a normal state by referring to a second normal database storing permissible ranges for each operating status of the steam turbine;
Detecting an abnormality sign of the valve based on the vibration characteristics analyzed in the analyzing step and the permissible range of vibration characteristics in a normal state of the valve set in the setting step;
A program to run.

Images