Damage assessment device and damage assessment method

Abstract

To provide a damage evaluation device and a damage evaluation method capable of coping with employment diversification of an appliance, and achieving evaluation with high reliability.SOLUTION: A damage evaluation device in an embodiment is a damage evaluation device for evaluating, damage on an appliance, and comprises: an operation data acquisition part for detecting a state of an appliance and acquiring the same as operation data; an operation state amount evaluation part for, on the basis of the operation data, calculating an operation state amount including at least one of, a temperature and generated stress, on a prescribed evaluation part of the appliance; a material deterioration evaluation part for evaluating a material deterioration amount of a material forming the appliance, on the basis of the operation state amount; a risk evaluation part for evaluating at least one of, a material cumulative damage amount and a breakage risk of the material forming the appliance, on the basis of the operation state amount and the material deterioration amount; and a maintenance recommendation period presenting part for, on the basis of the evaluation result of the risk evaluation part, presenting a maintenance recommendation period of the appliance.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE An embodiment of the present invention relates to an apparatus and method for assessing the amount of damage caused by the operation of equipment, such as power generation equipment. [Background technology]

[0002] It is known that damage and deterioration occur and accumulate in each part of the main components of thermal power plants, such as turbines, casings, and control valves, during operation, and the risk of failure of the components increases over time. Therefore, in order to operate these thermal power plants soundly and economically, it is necessary to quantitatively grasp the damage that occurs and accumulates in each part of the components during operation and to perform maintenance such as repairs and part replacement at the appropriate time.

[0003] One example of damage is the initiation and growth of cracks in components used in high-temperature environments. It is known that the initiation and growth of cracks are caused by creep and metal fatigue. Creep is a phenomenon in which, when a metallic material is used in a temperature environment at about half its melting point, even a low stress below the strength of the metallic material gradually causes permanent deformation over time, eventually causing cracks and breaking the metal. Fatigue is a phenomenon in which, even if a stress that would not break under static load occurs repeatedly, cracks occur and grow, leading to breakage. This repeated stress is caused not only by external forces but also by thermal stress. For example, in thermal power plant equipment, it is unavoidable to use it in a high-temperature environment and to generate stress during operation and start-up and shutdown, and damage due to these factors accumulates in each part as the equipment operates. In order to avoid equipment damage due to such creep and fatigue, appropriate maintenance management is required for thermal power plant equipment.

[0004] For example, in steam turbines, the maintenance and management of damage caused by crack initiation and propagation is particularly important for the turbine shaft (hereafter referred to simply as the rotor) and turbine casing. The rotor is the rotating shaft that transmits the torque received by the moving blades from the steam flow to the generator, and the turbine casing is the cover that surrounds the rotor. The steam flows between the turbine casing and the rotor, and the moving blades on the outer periphery of the rotor generate torque from the steam flow. The rotor has multiple stages of moving blades arranged on the outer periphery, and when these moving blades receive the steam flow, a torque is generated in the rotor. On the other hand, the steam that flows in at a high temperature consumes energy by passing through each stage of the moving blades, so the steam temperature decreases as it goes downstream. Therefore, the rotor and turbine casing that come into contact with this steam are used in a high-temperature environment, and temperature distribution also occurs within the same material.

[0005] These rotors and turbine casings are subjected to thermal stress due to temperature changes, such as heating and cooling, during start-up and shutdown and load fluctuations. In addition, stress is constantly generated by centrifugal force as the rotor rotates at high speed during operation. Fatigue damage accumulates due to such thermal stress, and creep damage accumulates due to centrifugal force in a high-temperature environment.

[0006] The progression of damage is influenced not only by temperature changes and stress, but also by the material properties of the components being evaluated. It is known that these material properties also deteriorate due to high temperature environments and applied stress. Therefore, the material properties used in creep and fatigue damage evaluations must be appropriately revised in accordance with material deterioration.

[0007] Examples of material degradation include a decrease in hardness and embrittlement. It is generally known that there is a correlation between material strength and hardness, and as hardness decreases, strength properties such as creep and fatigue properties also decrease. In turbine equipment, since it is difficult to obtain samples of sufficient size and quantity for evaluating strength properties from equipment in operation, changes in these strength properties are often estimated from hardness measurement results, which are relatively easy to measure. In addition, since material embrittlement affects the crack propagation speed, it is difficult to evaluate the progress of cracks during operation unless embrittlement is properly evaluated. In other words, appropriate damage management of turbine equipment requires evaluation of the temperature, generated stress, and amount of material degradation of each component during plant operation.

[0008] Conventionally, material degradation evaluations have been performed by opening the steam turbine when the plant is shut down. Material degradation is evaluated by hardness measurement and embrittlement evaluation of the evaluation area, the temperature and stress of each part during operation and at start and stop are evaluated by finite element analysis and design conditions, and the number and time of exposure to those temperatures and stresses are evaluated from operation data to evaluate fatigue damage and creep damage of each part. This material degradation progresses with the operation of the plant, so regular measurements are required to properly evaluate the amount of material degradation. However, shutting down a power plant and opening up the steam turbine increases the cost of power generation due to the effort and time required. Therefore, it is difficult to ensure a sufficient number of evaluations due to cost constraints.

[0009] In addition, conventional thermal power plants are mainly operated as base load plants, and are often operated near the rated output where plant efficiency is at its maximum. In such operating cases, the temperature and stress (hereinafter referred to as "operating state quantities") generated in each part of the rotor and turbine casing are very clear because they are precisely evaluated and optimized during the turbine design stage, and the operating state quantities are also unlikely to fluctuate because there is little fluctuation in turbine output during operation. Therefore, it was relatively easy to calculate the temperature and load stress of the evaluation parts and evaluate creep damage based on the design data and operation history.

[0010] However, in recent years, with the spread of renewable energy, the number of partial load operations at thermal power plants has increased, and the number of starts and stops has also increased. The increase in partial load operations leads to an increase in operations outside the design point, and turbine equipment is exposed for long periods of time to temperatures and load stresses that were not anticipated at the time of design. Therefore, if creep damage evaluation is performed based on design data and operating history, assuming that most operations are performed near the rated output, the evaluation accuracy is likely to decrease significantly.

[0011] In addition, the thermal stress evaluation associated with temperature changes during load fluctuations and start-up and shutdown also requires accuracy. The magnitude of thermal stress is related to the temperature change of the turbine equipment and the temperature distribution including the surrounding equipment. When considering temperature changes when the turbine is stopped, the temperature of each part decreases from the steady state due to natural cooling. Since the cooling rate differs depending on the part, the temperature does not decrease uniformly, and the temperature difference between the surrounding turbine equipment and the temperature difference within the same material is constantly changing, and the corresponding thermal stress occurs. In addition, it takes several days for the turbine equipment, including the rotor and casing, to cool down to room temperature. If the plant is started again before it is cooled to this room temperature, the temperature distribution at start-up and the amount of temperature change until the steady state are not uniform. In other words, the thermal stress that occurs repeatedly due to start-up and shutdown differs depending on the start-up and shutdown conditions. Similarly, even in partial load operation, the thermal stress differs depending on the load change conditions. Compared to conventional operation as a baseload power source, in recent operations with many start-ups and shutdowns and partial load operations, these conditions have become more diverse and difficult to predict. In other words, fatigue damage evaluation that simply focuses on the number of starts and shutdowns is considered to have low evaluation accuracy.

[0012] Damage assessment of turbine equipment caused by crack initiation or crack propagation requires proper evaluation of material degradation over time, creep damage, and fatigue damage. On the other hand, material degradation such as hardness reduction and embrittlement progresses due to temperature and load stress. In other words, material degradation progresses with plant operation, so periodic material property evaluation is necessary to properly assess damage. However, direct measurement of the evaluation site requires opening the turbine, which is troublesome and costly. Furthermore, partial load operation and the number of start-stops are expected to increase in recent years. As a result, turbine equipment will be exposed to temperatures and pressures that were not assumed at the time of design for long periods of time, and there is a concern that the accuracy of creep damage assessments based on operation near the rated output will decrease. In addition, in the case of fatigue damage caused by thermal stress, it is difficult to predict the thermal stress that occurs in recent diversified operation patterns, and fatigue damage assessments that simply focus on the number of start-stops and load changes are not reliable. [Prior art documents] [Non-patent literature]

[0013] [Non-Patent Document 1] Kazunari Fujiyama and 4 others, "Life Assessment Method and Life Diagnosis System for Steam Turbine Parts Considering Aging Degradation", Materials, Japan Society for Materials Science, March 15, 1988, Vol. 37, No. 414, pp. 315-321 [Non-Patent Document 2] Yusuke Suzuki and 3 others, "Remaining Life Assessment Using a Creep Softening Prediction Model for Modified 9Cr-1Mo Steel", Proceedings of the Academic Conference of the Japan Society for Materials Science, The Japan Society for Materials Science, May 25, 2012, Vol. 61, pp. 331-332 [Non-Patent Document 3] Hiromi Uemura et al., "Temper Embrittlement Properties of Cr-Mo-V Steel Turbine Rotors during Service", Iron and Steel, Iron and Steel Institute of Japan, April 1, 2007, Vol. 93, No. 4, pp. 324-329 Summary of the Invention [Problem to be solved by the invention]

[0014] As described above, conventional damage assessment devices and damage assessment methods have problems in that they require opening up the turbine, which increases the labor and cost, and makes it difficult to perform accurate and reliable assessment. The damage assessment device and damage assessment method according to the embodiment have been made to solve these problems, and have an object to provide a damage assessment device and damage assessment method that can accommodate diversifying equipment operations and achieve highly reliable assessment. [Means for solving the problem]

[0015] The damage assessment device of the embodiment is a damage assessment device that assesses damage to equipment, and includes an operating data acquisition unit that detects the state of the equipment and acquires it as operating data, an operating state quantity evaluation unit that calculates operating state quantities including at least one of the temperature and generated stress at a specified evaluation portion of the equipment based on the operating data, a material deterioration evaluation unit that evaluates the amount of material deterioration of the materials that make up the equipment based on the operating state quantities, a risk assessment unit that evaluates at least one of the cumulative damage amount and breakage risk of the materials that make up the equipment based on the operating state quantities and the material deterioration amount, and a recommended maintenance timing presentation unit that presents a recommended maintenance timing for the equipment based on the evaluation results of the risk assessment unit.

[0016] The damage assessment method of one embodiment is a damage assessment method for assessing damage to equipment, which detects the state of the equipment and acquires it as operating data, calculates operating state quantities including at least one of the temperature and generated stress at a specified evaluation portion of the equipment based on the operating data, evaluates the amount of material deterioration of the materials that make up the equipment based on the operating state quantities, evaluates at least one of the cumulative damage amount and breakage risk of the materials that make up the equipment based on the operating state quantities and the material deterioration amounts, and presents a recommended maintenance timing for the equipment based on the evaluation results of the risk assessment unit. [Brief description of the drawings]

[0017] [Figure 1] 1 is a block diagram showing a configuration of a damage assessment device according to an embodiment. FIG. [Diagram 2] FIG. 4 is a schematic diagram showing an example of an attachment position of a sensor according to the embodiment. [Diagram 3]5 is a flowchart showing an operation of a driving data acquisition unit according to the embodiment. [Figure 4] 5 is a flowchart showing the operation of a material deterioration assessment unit according to the embodiment. [Diagram 5] 10 is a flowchart showing an operation of a risk assessment unit according to the embodiment. [Figure 6] FIG. 2 is a diagram illustrating creep damage evaluation according to an embodiment. [Figure 7] FIG. 1 is a diagram illustrating a fatigue damage evaluation according to an embodiment. [Figure 8] FIG. 1 is a diagram for explaining a crack growth evaluation according to an embodiment. [Figure 9] FIG. 1 is a diagram for explaining a crack growth evaluation according to an embodiment. [Figure 10] FIG. 13 is a diagram illustrating a damage risk assessment according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Configuration of the embodiment) Hereinafter, an embodiment will be described in detail with reference to the drawings. The damage assessment device of this embodiment assesses damage to turbine equipment. As shown in Fig. 1, the damage assessment device 1 of the embodiment includes a sensor 10, an operation data acquisition unit 20, an evaluation component material storage unit 30, an input unit 35, an operation data storage unit 40, an operation state quantity evaluation unit 50, a material deterioration evaluation unit 60, a risk evaluation unit 70, and a maintenance recommendation timing presentation unit 80.

[0019] The operation data acquisition unit 20 is a calculation block that acquires operation data via the sensor 10. The evaluation component material storage unit 30 stores material data of materials that constitute the turbine equipment. The input unit 35 is an input interface such as a keyboard, and is used to store material data and the like in advance in the evaluation component material storage unit 30. The operation data storage unit 40 stores operation data indicating the state of each part of the components that constitute the turbine equipment. The operation state quantity evaluation unit 50 is a calculation block that evaluates the operation state quantity based on the operation data and the like acquired by the operation data acquisition unit. The material deterioration evaluation unit 60 is a calculation block that evaluates material deterioration using the evaluation result of the operation state quantity and material data such as chemical components of the evaluation component. The risk evaluation unit 70 is a calculation block that evaluates accumulated damage and damage risk based on the evaluation result of the material deterioration and the evaluation result of the operation state quantity. The recommended maintenance time presentation unit 80 is an interface that presents the recommended maintenance time to the user based on the evaluation results of the accumulated damage and damage risk and the future plant operation plan.

[0020] The evaluated component material storage unit 30 stores material data for components of a turbine device, such as a rotor and a turbine casing. The evaluated component material storage unit 30 can be realized by a non-volatile memory, a hard disk drive, or the like.

[0021] The operation data storage unit 40 stores operation data indicating the state of each part of the components that make up the turbine equipment. The operation data storage unit 40 can be realized by a non-volatile memory, a hard disk drive, or the like. The operation data storage unit 40 may not only store acquired operation data, but also store past operation data as history data. The history data includes operation data obtained from moment to moment, accumulated history such as total operation time, changes in temperature, pressure, etc. of each part during start-up, stoppage, or output fluctuation, and changes per unit time. The operation data storage unit 40 may store state quantities corresponding to the operation data of the evaluation part and their history data, in addition to the operation data and their history data.

[0022] (Sensor 10) The sensor 10 acquires operation data of the turbine equipment. Examples of the operation data acquired by the sensor 10 include the temperature and pressure at the steam inlet and outlet sides, the extraction temperature and pressure, the casing temperature and strain, and the like. In addition, the sensor 10 may detect the temperature and pressure before and after the steam valve, the temperature of the steam valve casing, the plant output, the load ratio, and the like. The sensor 10 is installed in advance during plant design and manufacturing, or is newly added for evaluation purposes.

[0023] Fig. 2 shows an example of the mounting position of a sensor in a turbine casing of a turbine device. The turbine device 2 shown in Fig. 2 has a turbine casing 3, a rotor 4, and a plurality of rotor blades 5 forming stage group I and stage group II. Sensors 10a to 10h are disposed in this turbine casing. In the example shown in Fig. 2, the sensors 10a to 10h are temperature sensors that detect temperature.

[0024] Sensor 10a is disposed near the wake of the first stage rotor blade 5 from the steam inlet 11 in the turbine casing 3. Sensor 10b is disposed near the steam outlet 12 of stage group I in the turbine casing 3. Sensors 10c and 10d are disposed near the steam passage after the steam outlet 12 in the turbine casing 3. Sensors 10e and 10g are disposed near stage group II in the turbine casing 3. Sensor 10f is disposed near the steam inlet 13 of stage group II in the turbine casing 3. Sensor 10h is disposed near the steam outlet 14 of stage group II in the turbine casing 3.

[0025] In the turbine casing 3 shown in Fig. 2, when estimating the state quantity of each stage of the stage group I, the detection results of the sensor 10a near the steam inlet 11 and the sensor 10b at the steam outlet 12 can be used. When calculating each stage temperature using the steam inlet temperature and outlet temperature, the estimation error of the steam inlet / outlet temperature can be reduced by estimating the steam temperature from temperature measurement data at a position close to the steam inlet. Also, the error of each stage temperature calculated using this can be reduced.

[0026] Sensor 10a is disposed in the vicinity of the wake of the first stage moving blade from the steam inlet 11 in the turbine casing 3, but is not limited to this. The mounting position of each sensor varies depending on design conditions, and is not limited to the wake of the first stage moving blade, and may be other positions. For example, if it is difficult to measure the temperature at the position of sensor 10b due to the design of the turbine casing 3, the temperature may be estimated using the temperature of the steam passage portion after the steam outlet 12, which can be detected by sensors 10c and 10d. Sensors may be installed between stages, similar to sensor 10a.

[0027] The number of sensors 10 from which the operation data is extracted is determined according to the number of parts and positions of the parts to be evaluated and the estimation formula, and is therefore not limited to two parts near the steam inlet and steam outlet. For example, in the case of estimating the temperature from the steam inlet 11 of the stage group I to the vicinity of the rotor blade 5 of the first stage, data from the sensor 10a close to the evaluation part may be sufficient. In addition, data to be extracted to estimate each stage state quantity of the stage group II may be detected by detecting the temperature of each part using two sensors among the sensor 10f and the sensor 10g or the sensor 10h, or three sensors among the sensor 10f, the sensor 10g, and the sensor 10h. In addition, a plurality of sensors 10 may be prepared as data extraction targets, and a sensor to collect data may be selected according to collected data such as steam pressure and operation output, or estimated data such as estimated state quantities at any time. The same applies to pressure and strain sensors, and the arrangement of the sensors may be determined according to the location and content of the operation data to be detected.

[0028] In the above, a method of using the measured values ​​of a temperature sensor near or before and after the stage to estimate the temperature of each stage has been described, but the measured values ​​of a pressure sensor may be used in addition to the measured values ​​of the temperature sensor. For example, there is a method of calculating heat transfer using the dynamic viscosity coefficient, Reynolds number, Nusselt number, Prandtl number, etc. To calculate these values, steam pressure is also required as a parameter. In that case, a pressure sensor is provided as the sensor 10, and the values ​​of these parameters are calculated based on the measured values ​​and combined with the measured values ​​of the temperature sensor. This makes it possible to calculate the temperature of the stage to be estimated. In estimating pressure, strain, etc., it is also possible to estimate by combining the measured data of multiple types of state quantities.

[0029] (Driving data acquisition unit 20) The operation data acquiring unit 20 has a function of acquiring operation data measured by the sensors 10 provided in the turbine equipment 2 during operation at an appropriate sampling frequency, averaging and removing noise, and outputting the data to a subsequent process. In addition, the operation data acquiring unit 20 can select sensors 10 provided at various locations in the turbine equipment 2 according to the content of the operation data to be acquired, and acquire desired operation data from the sensors 10. In other words, when acquiring certain operation data, it is possible to set what data (temperature, pressure, etc.) to acquire from which sensor.

[0030] 3 shows the operation of acquiring operation data by the operation data acquiring unit 20. The operation data acquiring unit 20 reads operation data such as detection data such as temperature and pressure, plant output, and load ratio from the sensor 10 provided in the turbine device 2 (S21).

[0031] When the driving data is read, the driving data acquisition unit 20 performs data processing such as noise removal processing (S22) and averaging processing (S23) to organize the data.

[0032] When the operation data is organized, the operation data acquisition unit 20 reads out the history data from the operation data storage unit 40 (S24). Examples of the history data include operation data obtained from time to time, an accumulated history such as the total operation time, the amount of change in temperature and pressure of each part during start-up and stop or output fluctuation, and the amount of change per unit time. That is, the operation data acquisition unit 20 acquires the past history of the operation data in addition to the operation data acquired through the sensor 10. The history data may further include transient data showing the state of the plant at the evaluation time, data obtained by accumulating these transient data, the amount of change in temperature and pressure of each part of the turbine equipment 2, and data obtained by adding and subtracting data at multiple arbitrary times. The operation data acquisition unit 20 acquires the history data from the operation data storage unit 40.

[0033] Furthermore, the operation data acquiring unit 20 accumulates and performs calculation processing on the transient data (operation data) from the operation data storage unit 40 to generate history data (S25). The generated history data is stored in the operation data storage unit 40 (S26). Note that the history data generated by the operation data acquiring unit 20 is not limited to data based on operation data acquired through the sensor 10. In the case of an existing plant that has been in continuous operation for a certain period of time, the operation data acquiring unit 20 may acquire and accumulate an operation history from the start of operation to the installation of the device, and store it in the operation data storage unit 40. Furthermore, the operation data may be input through the input unit 35 and stored in the operation data storage unit 40.

[0034] (Operating state quantity evaluation unit 50) The operation state quantity evaluation unit 50 calculates state quantities of predetermined evaluation parts, such as the rotor 4 and the turbine casing 3, inside the turbine equipment 2, using the operation data and history data acquired and generated by the operation data acquisition unit 20. Examples of the state quantities calculated by the operation state quantity evaluation unit 50 include temperature, stress, strain, and the like, at the predetermined part to be evaluated of the turbine equipment. Note that the accumulated time during which the plant has been operated for each of these state quantities may be included in the state quantities.

[0035] Examples of calculation methods by the operation state quantity evaluation unit 50 include (1) a method of estimating the steam temperature for the temperature at any evaluation location based on the temperature measurement data of the steam inlet 11 and steam outlet 12 of the turbine casing 3 shown in Fig. 2 and conditions such as the turbine output, and calculating the heat balance of each stage of the turbine by a balance calculation, (2) a method of creating a relational equation between the measurement data of various sensors attached to a predetermined location such as the turbine casing 3 and the evaluation location temperature in advance and calculating from this, and (3) a method of creating a relational equation for the load stress at a predetermined location with the turbine output, the turbine inlet side temperature, the turbine outlet side temperature, the measurement data of the sensors 10a to 10h attached to a predetermined location such as the turbine casing 3, and calculating based on the created relational equation. Here, the conditions such as the turbine output and the relational equations can be stored in the operation data storage unit 40 in advance.

[0036] Depending on the plant configuration in which the damage assessment device 1 is installed, the equipment to be assessed, and the number of assessed parts, it may be difficult to perform calculation processing on all of the operation data sent sequentially. In such a case, for example, the state quantities of the evaluation parts for the operation data expected in advance may be stored in the operation data storage unit 40 in advance, and the state quantities at the predetermined evaluation parts may be output using the operation data stored in the operation data storage unit 40 instead of the operation data acquired by the sensor 10.

[0037] (Material Degradation Evaluation Section 60) The material deterioration evaluation unit 60 estimates the amount of material deterioration at an arbitrary evaluation portion of the turbine device 2 based on the state quantities at the predetermined evaluation portion calculated by the operating state quantity evaluation unit 50 and material data of the evaluation parts such as the rotor 4 and the turbine casing 3 stored in advance in the evaluation part material storage unit 30. Examples of the material data include chemical components of the material constituting the turbine device 2, crystal grain size, and strength data such as hardness, yield strength, and impact value. Examples of the amount of material deterioration include the amount of hardness reduction and the amount of embrittlement. 4 shows an example of the evaluation operation by the material deterioration evaluation unit 60. In the evaluation of the amount of material deterioration per unit time at the current time, the unit time refers to any time division within a time period in which the input operating state quantities such as temperature and stress can be considered constant. The unit time may be set in advance, or may be determined successively by monitoring changes in the operating state quantities and changes in the operating data that are inputs to the calculations. The material deterioration evaluation unit 60 acquires the state quantities calculated by the operating state quantity evaluation unit 50 (S61), and then acquires the material data of the evaluation part (S62).

[0038] The material deterioration evaluation unit 60 calculates the amount of material deterioration per unit time based on the material data and the operating state quantities of the evaluation portion using the following formula (S63). Material deterioration amount = f(material data, operating state amount, operating time) (1) In other words, the amount of material deterioration is calculated using an arithmetic formula with material data, operating state quantity, and operating time as parameters.

[0039] Next, the material deterioration assessment unit 60 calculates the amount of material deterioration at the current time by integrating the calculated amount of material deterioration per unit time (S64). The material deterioration assessment unit 60 stores the calculated amount of material deterioration in the evaluation component material storage unit 30 (S65).

[0040] Here, as an example of calculating the amount of material deterioration, an example of a formula used for estimating hardness will be shown. Hardness = f(material data, operating state quantity, operating time) = A + B g(S,T,t) (2) Here, A and B are constants determined from material data, and g(S,T,t) is a function of the stress, temperature, and operating time at the current time. An example of the function g is shown below. g(S,T,t) = ln{exp(E-H0) / F + β·(S / G) γ exp(-H / T) t} (3) Here, E, F, G, and H are constants determined from the material data of the evaluation area, β and γ are constants experimentally obtained in advance, H0 is the initial hardness, S is stress, T is temperature, and t is time.

[0041] As an example of calculating the amount of material deterioration, an example of a formula used for calculating the amount of embrittlement will be shown. Embrittlement amount = f(material data, operating state amount, operating time) = g(A,T) h(B,T,t) (4) Here, A and B are constants determined from material data, g(A,T) is a function of the material data constant and the operating temperature, and h(B,T,t) is a function of the material data constant, the operating temperature, and time. Constants A and B are calculated by weighting the mass of any impurity element from the chemical composition at the time of material production, and adding them together or by the product of the added values. A = (2·Si + Mn + Ni + Cu) × B ···(5) B = 10P + 5Sb + 4Sn + As (6) Here, Si, Mn, Ni, Cu, P, Sb, Sn, and As are the masses of the respective impurity elements.

[0042] In this way, the amount of material deterioration is expressed by the estimation formula as described above. It may also be evaluated by other estimation formulas. The amount of material deterioration per unit time is calculated based on these formulas, and the amount of material deterioration at the current time can be calculated by accumulating the calculated amount.

[0043] (Risk Assessment Section 70) The risk assessment unit 70 evaluates creep damage and fatigue damage of an arbitrary evaluation part at the present time and calculates the amount of damage using state quantities such as the temperature and load stress of the evaluation part acquired by the operation state quantity assessment unit 50 and the amount of material deterioration evaluated by the material deterioration assessment unit 60. It also has a function of predicting the amount of future deformation and evaluating the risk of breakage based on the obtained amount of damage and amount of material deterioration and an operation plan input separately. FIG. 5 shows the damage amount calculation operation by the risk assessment unit 70. In modifying the assessment formula per unit time at the current time, the unit time in creep damage assessment refers to any time division in a period in which the amount of material deterioration and state quantities such as temperature and stress can be considered constant. The unit time may be set in advance, or may be determined sequentially by monitoring changes in the operating state quantities and changes in the operating data that are inputs to the calculation. On the other hand, the unit time in fatigue damage refers to the time from when the generated stress or strain increases or decreases until it decreases or increases again, or until there is no change in the state quantities such as temperature and stress and these state quantities can be considered constant.

[0044] The risk assessment unit 70 acquires the amount of material deterioration assessed by the material deterioration assessment unit 60 from the evaluated component material storage unit 30 (S71), and calculates the amount of damage (S72). Next, the risk assessment unit 70 modifies the damage assessment formula per unit time based on the calculated amount of damage (S73).

[0045] Specifically, the risk assessment unit 70 modifies the creep rupture curve used for evaluating creep damage per unit time based on the hardness at the current time output from the material degradation assessment unit 60, and calculates the creep rupture time for the same state quantity from this formula. The ratio of this creep rupture time to unit time is the creep damage amount per unit time.

[0046] Figure 6 shows a schematic diagram of a creep rupture curve used to evaluate the crack initiation life due to creep. If material degradation occurs over time with plant operation, the time until crack initiation (life) will be shortened accordingly. Therefore, the curve is corrected, for example from curve C1 to curve C2 in Figure 6, depending on the amount of material degradation, for example, the decrease in hardness. An example of a correction formula for the creep rupture curve depending on hardness is shown below. A + B × log(S) + C × log(S) 2 = (T + 273)(D + log(tr)) ···(7) Here, S is stress, tr is creep rupture time, T is operating temperature, A, B, and C are variables determined by hardness, and D is a constant.

[0047] The risk assessment unit 70 calculates the accumulated creep damage amount at the current time by adding the calculated creep damage amount per unit time to the accumulated damage amount stored in the operation data storage unit 40 (S74). The risk assessment unit 70 stores the accumulated damage amount, the accumulated creep damage amount at the current time, etc. in the operation data storage unit 40 (S75).

[0048] The fatigue crack initiation evaluation can be calculated in the same manner as the creep damage evaluation. Figure 7 shows a schematic diagram of a fatigue curve used in the fatigue crack initiation evaluation. As in the creep damage evaluation described above, the risk evaluation unit 70 corrects the fatigue curve from curve F1 to curve F2 in Figure 7 in accordance with the material hardness. An example of the correction formula is shown below. ΔS = A × N B + C × N D (8) Here, ΔS is the stress or strain amplitude, N is the crack initiation life (the number of repetitions until cracks occur), A and B are variables determined by hardness, and C and D are constants determined by the evaluation location.

[0049] The number of repetitions that constitute the lifespan is calculated based on the amount of change in stress or strain generated per unit time, and the ratio of this number of repetitions to the number of stress or strain repetitions generated per unit time is the amount of fatigue damage per unit time. The amount of fatigue damage per unit time is then added to the cumulative damage amount stored in the operation data storage unit 40 and integrated to calculate the cumulative fatigue damage amount at the current time. The cumulative fatigue damage amount at the current time is also stored in the operation data storage unit 40.

[0050] In the above, we have shown an example where the damage rate was calculated assuming that the crack initiation is failure, but in the evaluation of damage due to crack propagation, the crack propagation curve is similarly modified according to the amount of material degradation to evaluate the crack propagation damage. Figures 8 and 9 show schematic diagrams of crack propagation curves. The crack propagation speed increases with material degradation, for example embrittlement. An example of the correction formula for the crack propagation curve is shown below. Modified creep crack propagation rate formula: da / dt = A × K B (9) Corrected formula for fatigue crack propagation rate: da / dN = C × ΔK D (10) where da / dt and da / dN are the crack propagation speeds, K is the stress intensity factor, ΔK is the stress intensity factor range, and A, B, C, and D are variables determined by the service temperature and the degree of embrittlement. In the examples shown in Figures 8 and 9, the characteristic lines showing the crack propagation speeds are modified from M1 to M2 and from M3 to M4.

[0051] The crack propagation speed is used to calculate the amount of crack growth per unit time, and the crack length is calculated by integrating the calculated amount. The amount of damage is calculated from the ratio of the crack length to the amount of material deterioration such as the amount of embrittlement, material data, and the limit crack length determined from the operating state amount, or the limit crack length previously determined from the design data. The amount of damage obtained is not only output as a result, but can also be stored in the operating data storage unit 40. The amount of damage may be evaluated separately for creep damage and fatigue damage, or may be evaluated together.

[0052] The risk assessment unit 70 assesses the risk of damage using the calculated amount of damage at the present time and other state quantities (S76). FIG. 10 shows an example of an assessment of the risk of damage in this embodiment. In this embodiment, the risk of damage is determined in advance based on the amount of damage and the total operating time. Each threshold value (A, B, a, b) shown in the figure is a constant that is determined in advance based on the design conditions of each evaluation target component and the material used. In this embodiment, the rotor and casing are used as examples, and the amount of damage is calculated from the expected damage form, but a prediction error in the amount of damage occurs due to material deterioration and variations in material strength. This error increases in proportion to the increase in operating time, so appropriate risk assessment is possible by assessing the risk of damage based on two parameters, the amount of damage and the total operating time.

[0053] For example, if the total operation time is a hours or more and the damage amount is A% or more, the risk of damage can be determined to be high. On the other hand, if the total operation time is b hours or less and the damage amount is B% or less, the risk of damage can be determined to be low.

[0054] In this evaluation, a method of evaluating risk using a matrix of two parameters was shown, but the method is not necessarily limited to this. For example, the equipment availability rate, average operating temperature, number of starts and stops, etc. may be used as parameters, or the damage amount may be evaluated by dividing it into parameters of creep damage amount and fatigue damage amount. It is also possible to calculate the failure probability using a probabilistic method, rather than determining the risk univocally using a matrix and parameters. In this embodiment, the failure risk is calculated using the damage amount estimated in real time based on the operating data, but a parameter that makes the calculated damage amount uncertain is also used in the failure risk evaluation to enable appropriate risk evaluation.

[0055] (Maintenance recommendation timing presentation unit 80) The maintenance recommendation timing presentation unit 80 predicts the future damage amount based on the data such as the accumulated damage, the damage amount generated by the risk evaluation unit 70, and the damage risk evaluation result, and based on the operation plan data input by the user via the input unit 35, and proposes the maintenance recommendation timing. The maintenance recommendation timing presentation unit 80 has a display device such as a display device, and can present the proposal content to the user. Here, the operation plan is information indicating, for example, the equipment availability rate, average output, start and stop frequency, etc., and is stored in advance in the operation data storage unit 40. The maintenance recommendation timing presentation unit 80 calculates the predicted material deterioration amount and accumulated damage amount for the given operation plan based on the data set of operation data and history data linked to the obtained damage amount and material deterioration data.

[0056] As a calculation example, an example using accumulated operation time will be described. From the relationship between the history data and the amount of material deterioration, an arbitrary time unit is set in advance, and by obtaining the relationship between the amount of material deterioration and the operation time in that time unit, it becomes possible to predict the transition of the amount of material deterioration from the operation time input by the user separately. Similarly, from the history data, the fluctuation of state quantities such as temperature and load stress in time units is predicted. The amount of creep damage is predicted from these amount of material deterioration and state quantities. Similarly, for fatigue damage, it becomes possible to predict the amount of fatigue damage by estimating the magnitude and number of load stresses generated per unit operation time and combining them with the material deterioration prediction. Note that while the accumulated operation time is used as a parameter in this example, it is also possible to use, for example, plant output, availability rate, or an evaluation formula.

[0057] The amount of damage predicted in this way is used to evaluate the risk of future damage again, and the recommended timing for maintenance is presented based on the results.The damage risk evaluation is performed using the method shown in Figure 10, and the recommended timing for maintenance is proposed based on the evaluation results.

[0058] In this way, according to the damage assessment device of the embodiment, the operating state quantity of an arbitrary evaluation part such as a rotor or a casing is calculated sequentially from data obtained during the operation of the turbine equipment, the material deterioration amount at the current time is estimated from the operating state quantity and the history data, and based on these, the cumulative damage evaluation due to crack initiation or progression and the damage risk evaluation are performed, and future operation plans and maintenance timing recommendations are performed. In other words, by calculating the material deterioration amount sequentially based on the obtained data, it is possible to reduce the opportunities for measuring the deterioration amount accompanied by turbine opening. In addition, by calculating and accumulating the creep damage amount and fatigue damage amount in a unit time in which the state quantities such as temperature and stress calculated sequentially can be considered constant, it is possible to appropriately evaluate the damage amount even in partial load operation accompanied by fluctuations in the state quantities.

[0059] These features are expected to lead to highly reliable maintenance management, because damage can be predicted based on the latest operating conditions, even when load fluctuations or the number of starts and stops increases. In addition, it is possible to predict the amount of material deterioration and damage without carrying out large-scale inspections such as turbine overhauls, and cost reductions can be expected. Note that, although this embodiment has been shown as an example of application to a thermal power plant composed of a steam turbine and a boiler, the present invention is not necessarily limited to this configuration.

[0060] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0061] 1...damage assessment device, 2...turbine equipment, 3...turbine casing, 4...rotor, 5...moving blades, 10, 10a to 10h...sensor, 20...operation data acquisition unit, 30...evaluation component material memory unit, 35...input unit, 40...operation data memory unit, 50...operation state quantity assessment unit, 60...material deterioration assessment unit, 70...risk assessment unit, 80...maintenance recommendation timing presentation unit.

Claims

1. A damage assessment device for assessing damage to equipment, comprising: an operating data acquisition unit that detects the state of the device using a sensor attached at a predetermined position and acquires the detected state as operating data; an operating state quantity evaluation unit that calculates an operating state quantity including at least one of a temperature, generated stress, and strain at a predetermined evaluation portion of the equipment based on a relational expression of an operating state quantity including at least one of a temperature, generated stress, and strain at a predetermined evaluation portion of the equipment, the relational expression being created in advance based on the operating data; a material deterioration evaluation unit that evaluates an amount of material deterioration of a material constituting the equipment based on the operational state quantity; a risk assessment unit that assesses at least one of an accumulated damage amount and a breakage risk of a material constituting the equipment based on the operational state amount and the material deterioration amount; A maintenance recommendation timing presentation unit that presents a maintenance recommendation timing for the device based on an evaluation result of the risk evaluation unit, The risk assessment unit includes: using damage evaluation formula information that gives at least one of a creep damage amount and a fatigue damage amount of the predetermined evaluation portion based on the operational state amount and the material deterioration amount, A creep damage amount per unit time calculated based on the operating state quantity during a unit time during which the operating state quantity can be considered constant, and A fatigue damage amount per unit time calculated based on information on the change in the operating state amount during a unit time from when the generated stress or the strain starts to increase or decrease until when the generated stress or the strain starts to increase or decrease again; Calculate the cumulative damage by integrating at least one of the following: A damage assessment device comprising:

2. 2. The damage assessment device according to claim 1, wherein the risk assessment unit determines a risk of damage to the assessment portion based on the cumulative damage amount and the operational state amount.

3. A sensor for detecting a state of the device; A storage unit that stores the operating data, The driving data acquisition unit accumulates the driving data based on the driving data acquired via the sensor and history data including the past driving data acquired from the storage unit, and stores the accumulated data in the storage unit.

3. The damage assessment device according to claim 1 or 2,

4. A material storage unit is further provided for storing material data including properties of materials constituting the device, The material deterioration evaluation unit calculates the cumulative damage amount based on the operation data and the material data.

3. The damage assessment device according to claim 1 or 2,

5. A damage assessment method for assessing damage to equipment, comprising: The state of the equipment is detected by a sensor attached at a predetermined position and acquired as operation data; Calculating an operating state quantity including at least one of a temperature, an occurring stress, and a strain at a predetermined evaluation portion of the equipment based on a relational expression of an operating state quantity including at least one of a temperature, an occurring stress, and a strain at a predetermined evaluation portion of the equipment, the relational expression being created in advance based on the operating data; evaluating an amount of deterioration of a material constituting the equipment based on the amount of operational state; evaluating at least one of an accumulated damage amount and a risk of damage of a material constituting the equipment based on the operational state amount and the material deterioration amount; presenting a recommended maintenance timing for the device based on an evaluation result of the risk evaluation unit; The assessment of at least one of the cumulative damage amount and the risk of failure is using damage evaluation formula information that gives at least one of a creep damage amount and a fatigue damage amount of the predetermined evaluation portion based on the operational state amount and the material deterioration amount, A creep damage amount per unit time calculated based on the operating state quantity during a unit time during which the operating state quantity can be considered constant, and A fatigue damage amount per unit time calculated based on information on the change in the operating state amount during a unit time from when the generated stress or the strain starts to increase or decrease until when the generated stress or the strain starts to increase or decrease again; Calculate the cumulative damage by integrating at least one of the following: A damage assessment method comprising:

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