A nuclear power plant steam turbine fault diagnosis method and system

Abstract

The application particularly relates to a nuclear power plant steam turbine fault diagnosis method and system, and belongs to the technical field of nuclear power plant steam turbines. The method comprises the following steps: step one, acquiring the operation parameters of the steam turbine in real time; step two, judging whether the steam turbine is in an undetached operation state according to the trip state of the steam turbine, if the steam turbine is in the undetached operation state, then the subsequent diagnosis is continuously executed, otherwise the diagnosis is terminated; step three, when the steam turbine is in the undetached operation state, acquiring the operation parameters of a steam turbine support system; step four, comparing the operation parameters of the steam turbine and the operation parameters of the steam turbine support system with preset threshold values, and executing multi-level logical reasoning to diagnose the fault cause and output a measure suggestion. The system is used for implementing the steps of the method. The application can automatically diagnose the fault cause and give a measure suggestion according to the fault phenomenon when the steam turbine is in fault.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant steam turbine technology, specifically to a method and system for diagnosing steam turbine faults in nuclear power plants, which is used to automatically diagnose the cause of a fault and provide suggestions for corrective measures based on the fault phenomena when a steam turbine fault occurs. Background Technology

[0002] Currently, fault diagnosis of nuclear power plant steam turbines mainly relies on the personal experience of operators and maintenance personnel. However, due to differences in experience levels and technical capabilities among different personnel, this method of diagnosis, which depends on manual experience, has the following technical drawbacks: First, the diagnostic results are subjective. Different people may make different judgments about the same fault phenomenon, and the accuracy of the diagnosis cannot be guaranteed. There is a risk of diagnostic errors or omissions. Second, the diagnostic timeliness is poor. When experienced personnel are not on site, they may not be able to analyze the cause of the fault in a timely and accurate manner, which will lead to delays in fault handling and failure to take the correct corrective measures in a timely manner. Third, diagnostic experience is difficult to pass on. Due to the lack of standardized diagnostic methods, it is difficult to effectively pass on and promote fault diagnosis experience.

[0003] In recent years, with the development of artificial intelligence technology, several automated methods for turbine fault diagnosis have been proposed. For example, patent application CN121412798A discloses a turbine unit fault diagnosis method based on correlation information fusion, which establishes correlation rules between fault symptoms and fault types from a data-driven perspective and uses DS evidence theory to fuse multiple fault symptoms for diagnosis. Patent application CN121881050A discloses a method and system for constructing a turbine unit fault diagnosis model, which performs fault diagnosis by constructing a deep learning network model. In addition, there are turbine anomaly identification methods based on machine learning algorithms.

[0004] However, these technologies all rely on data-driven or machine learning models and have the following shortcomings: First, it requires a large amount of historical operating data for model training, which is difficult to apply to nuclear power plants with insufficient data accumulation. Second, the diagnostic process is poorly interpretable, making it difficult to intuitively demonstrate the causal relationship between the cause of the fault and the fault phenomenon, and operators find it difficult to understand the reasoning basis of the diagnostic conclusions. Third, the model training and parameter tuning process is complex, the deployment cost is high, and the model generalization ability between different power plants is limited. Summary of the Invention

[0005] The purpose of this invention is to address the problems of existing nuclear power plant turbine fault diagnosis, such as the lack of standardized judgment criteria, over-reliance on the subjective experience of operation and maintenance personnel, inability to promptly analyze fault causes and take corrective measures when personnel are not present, reliance on large amounts of historical data for model training in data-driven or machine learning model-based diagnosis, poor interpretability of diagnostic results, and high deployment costs. This invention provides a method and system for nuclear power plant turbine fault diagnosis that does not rely on personnel experience and skills. Through standardized fault diagnosis, it avoids diagnostic errors or omissions caused by differences in individual experience. Through real-time automatic diagnostic logic, it quickly locates the cause of the fault and simultaneously provides suggested measures when a fault occurs. Through threshold logic judgment that requires no training data and whose diagnostic reasoning process is transparent and traceable, it reduces deployment difficulty and increases the trust of operators in the diagnostic conclusions.

[0006] The nuclear power plant turbine fault diagnosis method and system provided by this invention can automatically diagnose the cause of the fault based on the fault phenomenon when the turbine fails, and give corresponding measures and suggestions, thereby achieving standardization and automation of fault diagnosis.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for diagnosing faults in nuclear power plant steam turbines, which does not rely on machine learning models or data training, includes the following steps: Step 1: Real-time acquisition of turbine operating parameters; turbine operating parameters include turbine tripping status, speed, power, low-pressure cylinder exhaust temperature, low-pressure cylinder bypass spray valve status, bearing oil discharge temperature, radial bearing temperature, thrust bearing temperature, and upper and lower cylinder temperature difference. Step 2: Determine whether the turbine is in an active state based on its tripping status. If the turbine is in an active state, continue with the subsequent diagnostics; otherwise, terminate the diagnostics. Step 3: When the turbine is in the non-disconnected operation state, obtain the operating parameters of the turbine support system; the turbine support system includes the SRI system and the GGR system; the operating parameters of the turbine support system include the water tank level, main pipe pressure, cooling water flow regulating valve opening and water temperature of the SRI system, and the oil tank level and main pipe pressure of the GGR system. Step 4: Compare the operating parameters of the steam turbine and the operating parameters of the steam turbine support system with preset thresholds, perform multi-level logical reasoning, diagnose the cause of the fault, and output suggested measures.

[0008] As one possible approach, multi-level logical reasoning includes a first-level fault diagnosis, specifically: Determine whether the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the first temperature threshold; the first temperature threshold is the normal value of the exhaust temperature of the low-pressure cylinder of the steam turbine. If so, then it is further determined whether the turbine speed is greater than the first speed threshold and the turbine power is less than the first power threshold; the first speed threshold is the normal value of the turbine speed and the first power threshold is the normal value of the turbine power. If both conditions are met, then it is further determined whether the low-pressure cylinder bypass spray valve of the steam turbine has been opened; the status of the low-pressure cylinder bypass spray valve of the steam turbine includes closed and open states. If the low-pressure cylinder bypass spray valve of the steam turbine is closed, the fault is diagnosed as the steam turbine's low-pressure cylinder bypass spray valve not being opened properly, causing the exhaust temperature of the steam turbine's low-pressure cylinder to rise. The recommended measure is to open the steam turbine's low-pressure cylinder bypass spray valve.

[0009] As one possible approach, the first temperature threshold is 79°C, the first speed threshold is 600 RPM, and the first power threshold is 15% of full power.

[0010] As one possible implementation method, the turbine support system also includes a CRF system or a SEN system; multi-level logical reasoning includes a second-level fault diagnosis, specifically: When any one of the following conditions is met: the turbine's exhaust oil temperature exceeds the second temperature threshold, the turbine's radial bearing temperature exceeds the third temperature threshold of 107°C, or the turbine's thrust bearing temperature exceeds the fourth temperature threshold, the following diagnostic steps shall be performed in sequence: Determine whether the water tank level of the SRI system is lower than the first water level threshold; the first water level threshold is the normal value of the water tank level of the SRI system. If so, the cause of the fault is diagnosed as a leak in the SRI system, and the recommended measures are: verify the operation of the SRI system; Determine whether the main pipe pressure of the SRI system is lower than the first pressure threshold; the first pressure threshold is the normal value of the main pipe pressure of the SRI system. If so, the cause of the fault is diagnosed as a pump failure in the SRI system, and the recommended measures are: verify the operation of the SRI system's pumps; Determine whether the opening of the cooling water flow regulating valve of the SRI system is less than the first opening threshold and whether the water temperature of the SRI system is less than the fifth temperature threshold; the first opening threshold is the minimum opening of the cooling water flow regulating valve of the SRI system, and the fifth temperature threshold is the normal water temperature of the SRI system. If all conditions are met, the cause of the fault is diagnosed as a malfunction of the cooling water flow regulating valve in the SRI system; the recommended course of action is to check the cooling water flow regulating valve of the SRI system for malfunction. Determine whether the opening of the cooling water flow regulating valve of the SRI system is greater than 85% of the second opening threshold and whether the water temperature of the SRI system is greater than 35°C of the sixth temperature threshold; the second opening threshold is the maximum opening of the cooling water flow regulating valve of the SRI system, and the sixth temperature threshold is the normal water temperature of the SRI system. If both conditions are met, the cause of the fault is diagnosed as an abnormality in the cooling source of the SRI system, and the recommended measures are: check the operation of the CRF system or the SEN system. Determine if the fuel level in the GGR system's fuel tank is below the second liquid level threshold; the second liquid level threshold is the normal value for the fuel level in the GGR system's fuel tank. If so, the cause of the fault is diagnosed as a leak in the GGR system, and the recommended measures are: verify the operation of the GGR system; Determine whether the main pipe pressure of the GGR system is lower than the second pressure threshold; the second pressure threshold is the normal value of the main pipe pressure of the GGR system. If so, the cause of the fault is diagnosed as a failure of the oil pump in the GGR system, and the following measures are recommended: verify the operation of the oil pump in the GGR system; The second temperature threshold is the normal value of the turbine's exhaust oil temperature; the third temperature threshold is the normal value of the turbine's radial bearing temperature; and the fourth temperature threshold is the normal value of the turbine's thrust bearing temperature.

[0011] As one possible approach, the second temperature threshold is 77°C, the third temperature threshold is 107°C, and the fourth temperature threshold is 98.9°C.

[0012] As one possible implementation method, the first liquid level threshold is 1400mm, the first pressure threshold is 0.3MPa, the second liquid level threshold is -100mm, the second pressure threshold is 0.035MPa, the first opening threshold is 5%, the second opening threshold is 85%, the fifth temperature threshold is 35℃, and the sixth temperature threshold is 35℃.

[0013] As one possible approach, multi-level logical reasoning includes a third-level fault diagnosis, specifically: When any of the following conditions are met, the fault is diagnosed as the turbine being unable to continue operating, and the recommended solution is: Manually trip the turbine. The exhaust temperature of the low-pressure cylinder of the steam turbine is greater than the seventh temperature threshold. When the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the seventh temperature threshold, it will cause dynamic and static friction between the turbine blades, and the steam turbine will not be able to continue to operate. The turbine's exhaust oil temperature exceeds the eighth temperature threshold. Exceeding the eighth temperature threshold will cause severe wear of the turbine bearings, and the turbine will be unable to continue operating. The radial bearing temperature of the steam turbine exceeds the ninth temperature threshold. Exceeding the ninth temperature threshold will cause severe wear of the radial bearing and prevent the steam turbine from continuing to operate. The temperature of the turbine's thrust bearing exceeds the tenth temperature threshold. Exceeding the tenth temperature threshold will cause severe wear of the turbine's thrust bearing, rendering the turbine unable to continue operating. If the temperature difference between the upper and lower cylinders of the steam turbine exceeds the eleventh temperature threshold, it will cause water hammer damage to the steam turbine, and the steam turbine will be unable to continue operating.

[0014] As one possible approach, the seventh temperature threshold is 121℃, the eighth temperature threshold is 82℃, the ninth temperature threshold is 113℃, the tenth temperature threshold is 107℃, and the eleventh temperature threshold is 38℃.

[0015] As one possible approach, the turbine tripping status includes the turbine being in a tripped operating state and the turbine being in a non-tripped operating state; The tripping status of the steam turbine is obtained through the following steps: obtain the position signal of the steam turbine inlet shut-off valve. When the steam turbine inlet shut-off valve is not fully closed, it indicates that the steam turbine is in a non-tripping operation state; otherwise, it indicates that the steam turbine is in a tripping operation state.

[0016] As one possible approach, nuclear power plant turbine fault diagnosis methods also include outputting fault causes, results, and recommended measures to a display terminal or control system.

[0017] To achieve the above objectives, in a second aspect, the present invention also provides a nuclear power plant turbine fault diagnosis system, comprising: The data acquisition module is used to collect the operating parameters of the steam turbine and the operating parameters of the steam turbine support system in real time; The storage module is used to store preset threshold parameters and diagnostic logic rules; The processing module, connected to the data acquisition module and the storage module, is used to execute the steps of the above-mentioned nuclear power plant turbine fault diagnosis method based on the parameters acquired by the data acquisition module and the threshold parameters and diagnostic logic rules stored in the storage module. The output module, connected to the processing module, is used to output the cause of the fault and suggested solutions.

[0018] The advantages of this invention compared to the prior art are: First, by establishing a standardized fault diagnosis model that includes multi-level diagnostic logic, when a turbine malfunctions, the fault point can be quickly located and suggestions for measures can be given without relying on the personal experience and skills of operation and maintenance personnel. This effectively avoids diagnostic errors or omissions caused by differences in personnel experience.

[0019] Secondly, by constructing a diagnostic logic that can run automatically in real time, the system can automatically analyze the cause of the fault and provide suggestions for measures in the first instance when a fault occurs, without waiting for experienced personnel to arrive, effectively solving the problem of delayed fault handling due to the absence of personnel.

[0020] Third, by adopting a diagnostic method based on threshold judgment and logical reasoning, the model can be directly deployed without relying on any historical operational data for training, resulting in low deployment costs. At the same time, the diagnostic process is clear and transparent, with each level of diagnostic conclusion having clear judgment basis and physical causal logic support, providing good interpretability. Operators can intuitively understand the complete reasoning chain from fault phenomena to diagnostic conclusions.

[0021] Fourth, by correlating the turbine operating parameters with the turbine support system operating parameters for diagnosis, the root cause of the fault can be accurately located, thus improving the accuracy of the diagnosis.

[0022] Fifth, the three-level diagnostic architecture has a clear hierarchical relationship and logical progression, and can output different diagnostic conclusions and measures suggestions according to the severity of the fault, forming a complete diagnostic chain from early warning to emergency shutdown. Attached Figure Description

[0023] Figure 1 This is a logical schematic diagram of the nuclear power plant steam turbine fault diagnosis method provided in an embodiment of the present invention; Detailed Implementation

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0027] This embodiment provides a method for diagnosing turbine faults in nuclear power plants. This method does not rely on machine learning models or data training, but rather on preset threshold judgment rules and logical reasoning rules. It performs correlation analysis between turbine operating parameters and turbine support system operating parameters to achieve fault diagnosis, including the following steps: Step 1: Real-time acquisition of turbine operating parameters; turbine operating parameters include turbine tripping status, speed, power, low-pressure cylinder exhaust temperature, low-pressure cylinder bypass spray valve status, bearing oil discharge temperature, radial bearing temperature, thrust bearing temperature, and upper and lower cylinder temperature difference. Step 2: Determine whether the turbine is in an active state based on its tripping status. If the turbine is in an active state, continue with the subsequent diagnostics; otherwise, terminate the diagnostics. Step 3: When the turbine is in the non-disconnected operation state, obtain the operating parameters of the turbine support system; the turbine support system includes the SRI system and the GGR system; the operating parameters of the turbine support system include the water tank level, main pipe pressure, cooling water flow regulating valve SRI081VD opening degree and water temperature of the SRI system, and the oil tank level and main pipe pressure of the GGR system. Step 4: Compare the operating parameters of the steam turbine and the operating parameters of the steam turbine support system with preset thresholds, perform multi-level logical reasoning, diagnose the cause of the fault, and output suggested measures.

[0028] In this embodiment, the tripping state of the steam turbine includes the steam turbine being in a tripped operation state and the steam turbine being in a non-tripped operation state; The steam turbine is equipped with two steam turbine inlet shut-off valves, GSE001VV and GSE002VV; The tripping status of the steam turbine is obtained through the following steps: acquire the position signals of the steam turbine inlet shut-off valves GSE001VV and GSE002VV. When the steam turbine inlet shut-off valves GSE001VV or GSE002VV are not fully closed, it indicates that the steam turbine is in a non-tripping operation state; otherwise, it indicates that the steam turbine is in a tripping operation state.

[0029] In this embodiment, multi-level logical reasoning includes a first-level fault diagnosis, specifically: Determine whether the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the first temperature threshold; the first temperature threshold is the normal value of the exhaust temperature of the low-pressure cylinder of the steam turbine, and the first temperature threshold is 79℃; If so, then it is further determined whether the turbine speed is greater than the first speed threshold and the turbine power is less than the first power threshold; the first speed threshold is the normal value of the turbine speed, the first speed threshold is 600 RPM, and the first power threshold is the normal value of the turbine power, the first power threshold is 15% of full power; If both conditions are met, then it is further determined whether the low-pressure cylinder bypass spray valve of the steam turbine has been opened; the status of the low-pressure cylinder bypass spray valve of the steam turbine includes closed and open states. If the low-pressure cylinder bypass spray valve of the steam turbine is closed, the fault is diagnosed as the steam turbine's low-pressure cylinder bypass spray valve not being opened properly, causing the exhaust temperature of the steam turbine's low-pressure cylinder to rise. The recommended measure is to open the steam turbine's low-pressure cylinder bypass spray valve.

[0030] In this embodiment, the turbine support system also includes a CRF system or a SEN system; the multi-level logic reasoning includes a second-level fault diagnosis, specifically: The second temperature threshold is the normal value of the turbine's oil discharge temperature, which is 77℃. When the turbine's oil discharge temperature exceeds the second temperature threshold, the following diagnostic steps are executed sequentially: (1) Determine whether the water tank level of the SRI system is lower than the first water level threshold; the first water level threshold is the normal value of the water tank level of the SRI system. The first water level threshold is 1400mm. When the water tank level of the SRI system is lower than the normal value, it indicates that there is a leak in the SRI system, which leads to a decrease in cooling capacity. If so, the cause of the fault is diagnosed as insufficient cooling capacity due to a leak in the SRI system, and the recommended measures are: verify the operation of the SRI system; (2) Determine whether the main pipe pressure of the SRI system is lower than the first pressure threshold; the first pressure threshold is the normal value of the main pipe pressure of the SRI system. The first pressure threshold is 0.3MPa. When the main pipe pressure of the SRI system is lower than the normal value, it indicates that the water pump of the SRI system is faulty and cannot provide enough pressure to achieve the normal flow rate of cooling water, resulting in the inability to effectively cool the lubricating oil of the steam turbine. If so, the cause of the fault is diagnosed as insufficient cooling water pressure due to a water pump failure in the SRI system. The recommended measures are: verify the operation of the water pump in the SRI system. (3) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is less than the first opening threshold and the water temperature of the SRI system is less than the fifth temperature threshold; the first opening threshold is the minimum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, which is 5%; the fifth temperature threshold is the normal water temperature of the SRI system, which is 35℃. If both conditions are met, it indicates that the cooling water flow regulating valve SRI081VD of the SRI system has failed to open to the required opening degree, the cooling water flow rate is reduced, and the turbine lubricating oil cannot be effectively cooled, resulting in an increase in the turbine's exhaust oil temperature: If both conditions are met, the fault is diagnosed as a fault in the SRI system's cooling water flow regulating valve SRI081VD, resulting in insufficient cooling water flow. The recommended solution is to check the SRI system's cooling water flow regulating valve SRI081VD for faults. (4) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is greater than the second opening threshold and whether the water temperature of the SRI system is greater than the sixth temperature threshold; the second opening threshold is the maximum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, and the second opening threshold is 85%; the sixth temperature threshold is the normal water temperature of the SRI system, and the sixth temperature threshold is 35℃. When both of these conditions are met, it indicates that the cooling water temperature of the SRI system is too high and cannot effectively cool the lubricating oil of the turbine, resulting in an increase in the exhaust oil temperature of the turbine and an abnormality in the cold source of the SRI system: If both conditions are met, the cause of the fault is diagnosed as an abnormality in the cold source of the SRI system, resulting in excessively high cooling water temperature. The recommended measures are: check the operation of the CRF system or the SEN system. (5) Determine whether the oil level in the GGR system tank is lower than the second liquid level threshold; the second liquid level threshold is the normal value of the oil level in the GGR system tank. The second liquid level threshold is -100mm. When the oil level in the GGR system tank is lower than the normal value, it indicates that there is a leak in the GGR system, resulting in insufficient lubricating oil supply. If so, the cause of the fault is diagnosed as insufficient lubricant supply due to a leak in the GGR system. The recommended measures are: verify the operation of the GGR system. (6) Determine whether the main pipe pressure of the GGR system is lower than the second pressure threshold; the second pressure threshold is the normal value of the main pipe pressure of the GGR system, which is 0.035MPa. When the main pipe pressure of the GGR system is lower than the normal value, it indicates that the oil pump of the GGR system is faulty and cannot provide enough pressure to achieve the normal flow rate of lubricating oil, and cannot provide enough lubricating oil to the turbine. If so, the cause of the fault is diagnosed as insufficient lubricating oil pressure due to a faulty oil pump in the GGR system. The recommended measures are: verify the operation of the oil pump in the GGR system. The third temperature threshold is the normal value for the radial bearing temperature of the steam turbine, which is 107℃. When the radial bearing temperature of the steam turbine exceeds the third temperature threshold, the following diagnostic steps are performed sequentially: (1) Determine whether the water tank level of the SRI system is lower than the first water level threshold; the first water level threshold is the normal value of the water tank level of the SRI system. The first water level threshold is 1400mm. When the water tank level of the SRI system is lower than the normal value, it indicates that there is a leak in the SRI system, which leads to a decrease in cooling capacity. If so, the cause of the fault is diagnosed as insufficient cooling capacity due to a leak in the SRI system, and the recommended measures are: verify the operation of the SRI system; (2) Determine whether the main pipe pressure of the SRI system is lower than the first pressure threshold; the first pressure threshold is the normal value of the main pipe pressure of the SRI system. The first pressure threshold is 0.3MPa. When the main pipe pressure of the SRI system is lower than the normal value, it indicates that the water pump of the SRI system is faulty and cannot provide enough pressure to achieve the normal flow rate of cooling water, and cannot effectively cool the lubricating oil of the turbine, resulting in the temperature of the radial bearing of the turbine rising. If so, the cause of the fault is diagnosed as insufficient cooling water pressure due to a water pump failure in the SRI system. The recommended measures are: verify the operation of the water pump in the SRI system. (3) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is less than the first opening threshold and the water temperature of the SRI system is less than the fifth temperature threshold; the first opening threshold is the minimum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, which is 5%; the fifth temperature threshold is the normal water temperature of the SRI system, which is 35℃. If both conditions are met, it indicates that the cooling water flow regulating valve SRI081VD of the SRI system has failed to open to the required opening degree, the cooling water flow rate is reduced, and the turbine lubricating oil cannot be effectively cooled, resulting in an increase in the radial bearing temperature of the turbine: If both conditions are met, the fault is diagnosed as a fault in the SRI system's cooling water flow regulating valve SRI081VD, resulting in insufficient cooling water flow. The recommended solution is to check the SRI system's cooling water flow regulating valve SRI081VD for faults. (4) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is greater than the second opening threshold and whether the water temperature of the SRI system is greater than the sixth temperature threshold; the second opening threshold is the maximum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, and the second opening threshold is 85%; the sixth temperature threshold is the normal water temperature of the SRI system, and the sixth temperature threshold is 35℃. When both of these conditions are met, it indicates that the cooling water temperature of the SRI system is too high and cannot effectively cool the lubricating oil of the turbine, resulting in an increase in the radial bearing temperature of the turbine and an abnormality in the cold source of the SRI system: If both conditions are met, the cause of the fault is diagnosed as an abnormality in the cold source of the SRI system, resulting in excessively high cooling water temperature. The recommended measures are: check the operation of the CRF system or the SEN system. (5) Determine whether the oil level in the GGR system tank is lower than the second liquid level threshold; the second liquid level threshold is the normal value of the oil level in the GGR system tank. The second liquid level threshold is -100mm. When the oil level in the GGR system tank is lower than the normal value, it indicates that there is a leak in the GGR system, resulting in insufficient lubricating oil supply. If so, the cause of the fault is diagnosed as insufficient lubricant supply due to a leak in the GGR system. The recommended measures are: verify the operation of the GGR system. (6) Determine whether the main pipe pressure of the GGR system is lower than the second pressure threshold; the second pressure threshold is the normal value of the main pipe pressure of the GGR system, which is 0.035MPa. When the main pipe pressure of the GGR system is lower than the normal value, it indicates that the oil pump of the GGR system is faulty and cannot provide enough pressure to achieve the normal flow rate of lubricating oil, and cannot provide enough lubricating oil to the turbine, resulting in an increase in the radial bearing temperature of the turbine. If so, the cause of the fault is diagnosed as insufficient lubricating oil pressure due to a faulty oil pump in the GGR system. The recommended measures are: verify the operation of the oil pump in the GGR system. The fourth temperature threshold is the normal temperature value of the turbine's thrust bearing, which is 98.9℃. When the turbine's thrust bearing temperature exceeds the fourth temperature threshold, the following diagnostic steps are performed sequentially: (1) Determine whether the water tank level of the SRI system is lower than the first water level threshold; the first water level threshold is the normal value of the water tank level of the SRI system. The first water level threshold is 1400mm. When the water tank level of the SRI system is lower than the normal value, it indicates that there is a leak in the SRI system, which leads to a decrease in cooling capacity. If so, the cause of the fault is diagnosed as insufficient cooling capacity due to a leak in the SRI system, and the recommended measures are: verify the operation of the SRI system; (2) Determine whether the main pipe pressure of the SRI system is lower than the first pressure threshold; the first pressure threshold is the normal value of the main pipe pressure of the SRI system. The first pressure threshold is 0.3MPa. When the main pipe pressure of the SRI system is lower than the normal value, it indicates that the water pump of the SRI system is faulty and cannot provide enough pressure to achieve the normal flow rate of cooling water, and cannot effectively cool the lubricating oil of the turbine, resulting in the temperature of the thrust bearing of the turbine rising. If so, the cause of the fault is diagnosed as insufficient cooling water pressure due to a water pump failure in the SRI system. The recommended measures are: verify the operation of the water pump in the SRI system. (3) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is less than the first opening threshold and the water temperature of the SRI system is less than the fifth temperature threshold; the first opening threshold is the minimum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, which is 5%; the fifth temperature threshold is the normal water temperature of the SRI system, which is 35℃. If both conditions are met, it indicates that the cooling water flow regulating valve SRI081VD of the SRI system has failed to open to the required opening degree, the cooling water flow rate is reduced, and the turbine lubricating oil cannot be effectively cooled, resulting in an increase in the temperature of the turbine thrust bearing: If both conditions are met, the fault is diagnosed as a fault in the SRI system's cooling water flow regulating valve SRI081VD, resulting in insufficient cooling water flow. The recommended solution is to check the SRI system's cooling water flow regulating valve SRI081VD for faults. (4) Determine whether the opening degree of the cooling water flow regulating valve SRI081VD of the SRI system is greater than the second opening threshold and whether the water temperature of the SRI system is greater than the sixth temperature threshold; the second opening threshold is the maximum opening degree of the cooling water flow regulating valve SRI081VD of the SRI system, and the second opening threshold is 85%; the sixth temperature threshold is the normal water temperature of the SRI system, and the sixth temperature threshold is 35℃. When both of these conditions are met, it indicates that the cooling water temperature of the SRI system is too high and cannot effectively cool the lubricating oil of the turbine, resulting in an increase in the thrust bearing temperature of the turbine and an abnormality in the cold source of the SRI system: If both conditions are met, the cause of the fault is diagnosed as an abnormality in the cold source of the SRI system, resulting in excessively high cooling water temperature. The recommended measures are: check the operation of the CRF system or the SEN system. (5) Determine whether the oil level in the GGR system tank is lower than the second liquid level threshold; the second liquid level threshold is the normal value of the oil level in the GGR system tank. The second liquid level threshold is -100mm. When the oil level in the GGR system tank is lower than the normal value, it indicates that there is a leak in the GGR system, resulting in insufficient lubricating oil supply. If so, the cause of the fault is diagnosed as insufficient lubricant supply due to a leak in the GGR system. The recommended measures are: verify the operation of the GGR system. (6) Determine whether the main pipe pressure of the GGR system is lower than the second pressure threshold; the second pressure threshold is the normal value of the main pipe pressure of the GGR system, which is 0.035MPa. When the main pipe pressure of the GGR system is lower than the normal value, it indicates that the oil pump of the GGR system is faulty and cannot provide enough pressure to achieve the normal flow rate of lubricating oil, and cannot provide enough lubricating oil to the turbine, resulting in the temperature of the turbine thrust bearing rising. If so, the cause of the fault is diagnosed as insufficient lubricating oil pressure due to a faulty oil pump in the GGR system. The recommended solution is to verify the operation of the oil pump in the GGR system.

[0031] In this embodiment, multi-level logical reasoning includes a third level of fault diagnosis, specifically: When any of the following conditions are met, the fault is diagnosed as the turbine being unable to continue operating, and the recommended solution is: Manually trip the turbine. The exhaust temperature of the low-pressure cylinder of the steam turbine is greater than the seventh temperature threshold. The seventh temperature threshold is 121℃. If the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the seventh temperature threshold, it will cause dynamic and static friction between the turbine blades, and the steam turbine will not be able to continue to operate. If the turbine's oil discharge temperature exceeds the eighth temperature threshold (82℃), it will cause severe wear on the turbine's bearings, rendering the turbine unable to continue operating. The radial bearing temperature of the steam turbine exceeds the ninth temperature threshold; the ninth temperature threshold is 113℃. If the radial bearing temperature of the steam turbine exceeds the ninth temperature threshold, it will cause severe wear of the radial bearing and the steam turbine will be unable to continue to operate. The temperature of the turbine's thrust bearing exceeds the tenth temperature threshold; the tenth temperature threshold is 107℃. If the temperature of the turbine's thrust bearing exceeds the tenth temperature threshold, it will cause severe wear of the turbine's thrust bearing, and the turbine will be unable to continue operating. The temperature difference between the upper and lower cylinders of the steam turbine is greater than the eleventh temperature threshold. The eleventh temperature threshold is 38℃. If the temperature difference between the upper and lower cylinders of the steam turbine exceeds the eleventh temperature threshold, it indicates that the steam turbine is at risk of water ingress, which will lead to water hammer damage to the steam turbine and prevent the steam turbine from continuing to operate.

[0032] In this embodiment, the nuclear power plant turbine fault diagnosis method also includes outputting the fault cause results and suggested measures to a display terminal or control system for reference by operators or for automatic execution by the control system.

[0033] In this embodiment, RPM stands for revolutions per minute; the SRI system is a conventional island-type closed cooling water system; the GGR system is a lubricating oil system; the CRF system is a circulating water system; and the SEN system is an auxiliary cooling water system.

[0034] This embodiment also provides a nuclear power plant steam turbine fault diagnosis system, including: The data acquisition module is used to collect the operating parameters of the steam turbine and the operating parameters of the steam turbine support system in real time; The storage module is used to store preset threshold parameters and diagnostic logic rules; The processing module, connected to the data acquisition module and the storage module, is used to execute the steps of the above-mentioned nuclear power plant turbine fault diagnosis method based on the parameters acquired by the data acquisition module and the threshold parameters and diagnostic logic rules stored in the storage module.

[0035] It should be noted that the specific threshold parameters in the embodiments are all preferred values, and in practical applications, they can be adaptively adjusted according to the specific model and operating procedures of the steam turbines in different nuclear power plants.

[0036] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for diagnosing faults in a nuclear power plant steam turbine, characterized in that, Training without relying on machine learning models or data includes the following steps: Step 1: Real-time acquisition of turbine operating parameters; turbine operating parameters include turbine tripping status, speed, power, low-pressure cylinder exhaust temperature, low-pressure cylinder bypass spray valve status, oil discharge temperature, radial bearing temperature, thrust bearing temperature, and upper and lower cylinder temperature difference. Step 2: Determine whether the turbine is in an active state based on its tripping status. If the turbine is in an active state, continue with the subsequent diagnostics; otherwise, terminate the diagnostics. Step 3: When the turbine is in the non-disconnected operation state, obtain the operating parameters of the turbine support system; the turbine support system includes the SRI system and the GGR system; the operating parameters of the turbine support system include the water tank level, main pipe pressure, cooling water flow regulating valve opening and water temperature of the SRI system, and the oil tank level and main pipe pressure of the GGR system. Step 4: Compare the operating parameters of the steam turbine and the operating parameters of the steam turbine support system with preset thresholds, perform multi-level logical reasoning, diagnose the cause of the fault, and output suggested measures.

2. The method for diagnosing nuclear power plant steam turbine faults according to claim 1, characterized in that, Multi-level logical reasoning includes first-level fault diagnosis, specifically: Determine whether the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the first temperature threshold; the first temperature threshold is the normal value of the exhaust temperature of the low-pressure cylinder of the steam turbine. If so, then it is further determined whether the turbine speed is greater than the first speed threshold and the turbine power is less than the first power threshold; the first speed threshold is the normal value of the turbine speed and the first power threshold is the normal value of the turbine power. If both conditions are met, then it is further determined whether the low-pressure cylinder bypass spray valve of the steam turbine has been opened; the status of the low-pressure cylinder bypass spray valve of the steam turbine includes closed and open states. If the low-pressure cylinder bypass spray valve of the steam turbine is closed, the fault is diagnosed as the steam turbine's low-pressure cylinder bypass spray valve not being opened properly, causing the exhaust temperature of the steam turbine's low-pressure cylinder to rise. The recommended measure is to open the steam turbine's low-pressure cylinder bypass spray valve.

3. The method for diagnosing turbine faults in nuclear power plants according to claim 2, characterized in that, The first temperature threshold is 79℃, the first speed threshold is 600RPM, and the first power threshold is 15% of full power.

4. The method for diagnosing turbine faults in nuclear power plants according to claim 1, characterized in that, The turbine support system also includes a CRF system or a SEN system; multi-level logical reasoning includes a second-level fault diagnosis, specifically: When any one of the following conditions is met: the turbine's exhaust oil temperature exceeds the second temperature threshold, the turbine's radial bearing temperature exceeds the third temperature threshold of 107°C, or the turbine's thrust bearing temperature exceeds the fourth temperature threshold, the following diagnostic steps shall be performed in sequence: Determine whether the water tank level of the SRI system is lower than the first water level threshold; the first water level threshold is the normal value of the water tank level of the SRI system. If so, the cause of the fault is diagnosed as a leak in the SRI system, and the recommended measures are: verify the operation of the SRI system; Determine whether the main pipe pressure of the SRI system is lower than the first pressure threshold; the first pressure threshold is the normal value of the main pipe pressure of the SRI system. If so, the cause of the fault is diagnosed as a pump failure in the SRI system, and the recommended measures are: verify the operation of the SRI system's pumps; Determine whether the opening of the cooling water flow regulating valve of the SRI system is less than the first opening threshold and whether the water temperature of the SRI system is less than the fifth temperature threshold; the first opening threshold is the minimum opening of the cooling water flow regulating valve of the SRI system, and the fifth temperature threshold is the normal water temperature of the SRI system. If all conditions are met, the cause of the fault is diagnosed as a malfunction of the cooling water flow regulating valve in the SRI system; the recommended course of action is to check the cooling water flow regulating valve of the SRI system for malfunction. Determine whether the opening degree of the cooling water flow regulating valve of the SRI system is greater than 85% of the second opening degree threshold and whether the water temperature of the SRI system is greater than the sixth temperature threshold of 35℃. The second opening threshold is the maximum opening value of the cooling water flow regulating valve of the SRI system, and the sixth temperature threshold is the normal water temperature value of the SRI system. If both conditions are met, the cause of the fault is diagnosed as an abnormality in the cooling source of the SRI system, and the recommended measures are: check the operation of the CRF system or the SEN system. Determine if the fuel level in the GGR system's fuel tank is below the second liquid level threshold; the second liquid level threshold is the normal value for the fuel level in the GGR system's fuel tank. If so, the cause of the fault is diagnosed as a leak in the GGR system, and the recommended measures are: verify the operation of the GGR system; Determine whether the main pipe pressure of the GGR system is lower than the second pressure threshold; the second pressure threshold is the normal value of the main pipe pressure of the GGR system. If so, the cause of the fault is diagnosed as a failure of the oil pump in the GGR system, and the following measures are recommended: verify the operation of the oil pump in the GGR system; The second temperature threshold is the normal value of the turbine's exhaust oil temperature; the third temperature threshold is the normal value of the turbine's radial bearing temperature; and the fourth temperature threshold is the normal value of the turbine's thrust bearing temperature.

5. The nuclear power plant turbine fault diagnosis method according to claim 4, characterized in that, The second temperature threshold is 77℃, the third temperature threshold is 107℃, and the fourth temperature threshold is 98.9℃.

6. The method for diagnosing turbine faults in nuclear power plants according to claim 4, characterized in that, The first liquid level threshold is 1400 mm, the first pressure threshold is 0.3 MPa, the second liquid level threshold is -100 mm, the second pressure threshold is 0.035 MPa, the first opening threshold is 5%, the second opening threshold is 85%, the fifth temperature threshold is 35℃, and the sixth temperature threshold is 35℃.

7. The method for diagnosing turbine faults in nuclear power plants according to claim 1, characterized in that, Multi-level logical reasoning includes a third level of fault diagnosis, specifically: When any of the following conditions are met, the fault is diagnosed as the turbine being unable to continue operating, and the recommended solution is: Manually trip the turbine. The exhaust temperature of the low-pressure cylinder of the steam turbine is greater than the seventh temperature threshold. When the exhaust temperature of the low-pressure cylinder of the steam turbine exceeds the seventh temperature threshold, it will cause dynamic and static friction between the turbine blades, and the steam turbine will not be able to continue to operate. The turbine's exhaust oil temperature exceeds the eighth temperature threshold. Exceeding the eighth temperature threshold will cause severe wear of the turbine bearings, and the turbine will be unable to continue operating. The radial bearing temperature of the steam turbine exceeds the ninth temperature threshold. Exceeding the ninth temperature threshold will cause severe wear of the radial bearing and prevent the steam turbine from continuing to operate. The temperature of the turbine's thrust bearing exceeds the tenth temperature threshold. Exceeding the tenth temperature threshold will cause severe wear of the turbine's thrust bearing, rendering the turbine unable to continue operating. If the temperature difference between the upper and lower cylinders of the steam turbine exceeds the eleventh temperature threshold, it will cause water hammer damage to the steam turbine, and the steam turbine will be unable to continue operating.

8. The method for diagnosing turbine faults in nuclear power plants according to claim 7, characterized in that, The seventh temperature threshold is 121℃, the eighth temperature threshold is 82℃, the ninth temperature threshold is 113℃, the tenth temperature threshold is 107℃, and the eleventh temperature threshold is 38℃.

9. The method for diagnosing faults in a nuclear power plant steam turbine according to claim 1, characterized in that, The tripping status of a steam turbine includes the steam turbine being in a tripped operating state and the steam turbine being in a non-tripped operating state. The tripping status of a steam turbine is obtained through the following steps: acquiring the position signal of the steam turbine inlet shut-off valve. When the steam turbine inlet shut-off valve is not fully closed, it indicates that the steam turbine is in a non-tripped operating state; otherwise, it indicates that the steam turbine is in a tripped operating state.

10. The method for diagnosing faults in a nuclear power plant steam turbine according to claim 1, characterized in that, It also includes outputting the cause of the fault, the result, and the suggested measures to the display terminal or control system.

11. A fault diagnosis system for a nuclear power plant steam turbine, characterized in that, include: The data acquisition module is used to collect the operating parameters of the steam turbine and the operating parameters of the steam turbine support system in real time; The storage module is used to store preset threshold parameters and diagnostic logic rules; The processing module, connected to the data acquisition module and the storage module, is used to execute the steps of the nuclear power plant turbine fault diagnosis method according to any one of claims 1-10, based on the parameters acquired by the data acquisition module and the threshold parameters and diagnostic logic rules stored in the storage module. The output module, connected to the processing module, is used to output the cause of the fault and suggested solutions.

12. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the nuclear power plant turbine fault diagnosis method according to any one of claims 1-10.

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