Method and system for monitoring on-line safe operation state of zero output of low-pressure cylinder of steam turbine

Abstract

The application discloses a steam turbine low-pressure cylinder zero-power online safe operation state monitoring method and system, which comprises the following steps: obtaining the low-pressure cylinder operation parameters, the medium-pressure cylinder related operation parameters and the related auxiliary machine operation parameters during the cylinder cutting process; determining the basic operation state of the low-pressure cylinder according to the low-pressure cylinder operation parameters, determining the air blowing state of the low-pressure cylinder, the water erosion state of the last-stage blade, the low-cycle fatigue damage cycles, the life consumption rate and the life damage accumulation of the cylinder and the rotor, the risk degree of the blade vibration and the vibration avoidance rate; monitoring the operation states of the medium-pressure cylinder and the auxiliary machine according to the medium-pressure cylinder related operation parameters and the related auxiliary machine operation parameters; and performing operation guidance according to the basic operation state of the low-pressure cylinder, the life consumption rate, the water erosion state, the medium-pressure cylinder operation state, the related auxiliary machine operation state and the vibration analysis result. Comprehensive online evaluation and analysis of the unit life, vibration, blade erosion and vibration during the low-pressure cylinder zero-power process are realized.

Description

Technical Field

[0001] This invention relates to the field of low-pressure cylinder operating status monitoring technology, and in particular to a method and system for monitoring the online safe operating status of a steam turbine low-pressure cylinder at zero output. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Zero output of the low-pressure cylinder, also known as low-pressure cylinder cut-off operation, low-pressure cylinder forced-air operation, or low-pressure cylinder micro-output operation, refers to a situation where all the exhaust steam from the intermediate-pressure cylinder is led out through the extraction steam pipe, and the low-pressure cylinder only has a small amount of cooling steam to carry away the heat generated by the friction between the rotor blades and the internal working fluid. The common characteristic is that the turbine's low-pressure cylinder operates at extremely low steam flow rates.

[0004] During the current energy transition period, thermal power units are required to have high operational flexibility, enabling them to adjust power generation loads over a wide range to absorb renewable energy. To improve the flexibility of combined heat and power (CHP) units, many CHP units have undergone low-pressure cylinder zero-output retrofitting. The frequent cylinder switching of the turbine's low-pressure cylinder in these units impacts the unit's safety. However, neither the original turbine design nor the low-pressure cylinder zero-output retrofitting process addressed the impact of long-term, frequent cylinder switching on the turbine's safety system, lacking comprehensive online evaluation and analysis of unit lifespan, vibration, and blade erosion. Clearly, this is a real and urgent problem for every unit that has undergone low-pressure cylinder zero-output retrofitting. This lack of online safety monitoring is no longer suitable for the current requirements of improved unit flexibility and seriously threatens the turbine's operational safety. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method and system for online safe operation monitoring of the low-pressure cylinder of a steam turbine at zero output. This system can comprehensively monitor, evaluate, and analyze the operating status, lifespan consumption, vibration, blade erosion, and flutter of the steam turbine during the zero-output process of the low-pressure cylinder.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Firstly, a method for monitoring the online safe operation status of the low-pressure cylinder of a steam turbine with zero output is proposed, including:

[0008] Acquire the operating parameters of the low-pressure cylinder, the operating parameters of the intermediate-pressure cylinder related to the cylinder cut, and the operating parameters of the auxiliary equipment during the cylinder cut process;

[0009] Based on the operating parameters of the low-pressure cylinder, determine the basic operating state of the low-pressure cylinder, the blowing state of the low-pressure cylinder, the water erosion state of the last stage blades, the temperature field and stress field of the cylinder, rotor and blades, and the dynamic stress distribution and dynamic stress characteristic value of the blades.

[0010] Based on the temperature and stress fields of the cylinder and rotor, determine the low-cycle fatigue damage cycles, life loss rate, and life damage accumulation of the cylinder and rotor.

[0011] Based on the dynamic stress distribution and dynamic stress characteristic values ​​of the blade, flutter analysis is performed on the blade to determine the risk of flutter and the flutter avoidance rate.

[0012] Based on the relevant operating parameters of the intermediate pressure cylinder and the relevant auxiliary equipment, the operating status of the intermediate pressure cylinder and the auxiliary equipment is monitored;

[0013] Operational guidance is provided based on the basic operating status of the low-pressure cylinder, its life loss rate, water erosion status, the operating status of the intermediate-pressure cylinder, the operating status of related auxiliary equipment, and the results of flutter analysis.

[0014] Secondly, a zero-output online safety operation status monitoring system for the low-pressure cylinder of a steam turbine is proposed, including:

[0015] The low-pressure cylinder zero-output cylinder cutting and cylinder insertion process data recording module is used to acquire the low-pressure cylinder operating parameters, the intermediate-pressure cylinder related operating parameters, and the related auxiliary machine operating parameters during the cylinder cutting process;

[0016] The blower status analysis module is used to determine the blower status of the low-pressure cylinder based on the operating parameters of the low-pressure cylinder.

[0017] The final stage water erosion monitoring module is used to determine the water erosion status of the final stage blades based on the operating parameters of the low-pressure cylinder.

[0018] The low-pressure cylinder rotor and cylinder temperature, stress, and life loss analysis module is used to determine the temperature field and stress field of the cylinder and rotor during cylinder cutting based on the low-pressure cylinder operating parameters; and to determine the low-cycle fatigue damage cycles, life loss rate, and life damage accumulation of the cylinder and rotor based on the temperature field and stress field of the cylinder and rotor.

[0019] The blade modal and stress analysis module is used to determine the temperature field and stress field of the blade, as well as the dynamic stress distribution and dynamic stress characteristic value of the blade, by acquiring the low-pressure cylinder operating parameters.

[0020] The blade flutter analysis and monitoring module is used to analyze the blade flutter based on the dynamic stress distribution and dynamic stress characteristic values ​​of the blade, and to determine the risk of blade flutter and the flutter avoidance rate.

[0021] The intermediate pressure cylinder related parameter monitoring and analysis module is used to monitor the operating status of the intermediate pressure cylinder based on the relevant operating parameters of the intermediate pressure cylinder, including the intermediate pressure cylinder exhaust steam parameters exceeding the limit, the pressure difference between the last two stages of the intermediate pressure cylinder regenerative extraction steam exceeding the limit, the vibration of the medium and low pressure connecting pipeline, the vibration of the cooling steam pipeline, etc.

[0022] The auxiliary equipment safety status analysis module is used to monitor the operating status of the auxiliary equipment based on the operating parameters of the auxiliary equipment, including condenser vacuum monitoring, condensate dissolved oxygen monitoring, condensate flow monitoring, and low-pressure cylinder bearing monitoring.

[0023] The operation guidance module provides operational guidance based on the basic operating status, life loss rate, water erosion status, intermediate cylinder operating status, related auxiliary machine operating status, and chatter analysis results of the low-pressure cylinder. When the basic operating status is abnormal, or the life loss rate of the low-pressure cylinder rotor or cylinder exceeds the loss rate threshold, or the chatter risk level exceeds the risk level threshold, it provides operational adjustment suggestions.

[0024] Thirdly, an electronic device is proposed, including a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When the computer instructions are executed by the processor, they complete the steps described in the method for monitoring the online safe operation status of the low-pressure cylinder of a steam turbine with zero output.

[0025] Fourthly, a computer-readable storage medium is proposed for storing computer instructions, which, when executed by a processor, complete the steps described in the method for monitoring the online safe operation status of a steam turbine's low-pressure cylinder with zero output.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. This invention can comprehensively evaluate and analyze the turbine's operating status, unit life, vibration, blade water erosion, flutter, and blower status during the zero-output process of the low-pressure cylinder, thereby improving the operational safety of the turbine unit after the low-pressure cylinder zero-output modification.

[0028] 2. When performing flutter analysis, this invention determines the risk level of blade flutter and the flutter avoidance rate, enabling a comprehensive understanding of the blade flutter situation.

[0029] 3. Based on the monitoring of operational safety, this invention can also provide operational guidance according to the monitoring results, making operation safer under the guidance measures.

[0030] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0032] Figure 1 This is a diagram showing the relationships between the modules used in the method disclosed in Example 1;

[0033] Figure 2 This is a diagram illustrating the practical application of the method disclosed in Example 1;

[0034] Figure 3 This is a temperature distribution diagram of the low-pressure rotor of the steam turbine when the low-pressure cylinder is operating at zero output, as disclosed in Example 1.

[0035] Figure 4 This is a stress distribution diagram of the low-pressure rotor of the steam turbine when the low-pressure cylinder is operating at zero output, as disclosed in Example 1.

[0036] Figure 5 This is a diagram showing the cylinder temperature distribution during zero-output operation of the low-pressure cylinder of the steam turbine as disclosed in Example 1.

[0037] Figure 6 This is a diagram showing the stress distribution of the low-pressure cylinder of the steam turbine during zero-output operation, as disclosed in Example 1.

[0038] Figure 7 This is a diagram showing the stress distribution of the turbine blades during zero-output operation of the low-pressure cylinder in Example 1. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, 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 pertains.

[0041] Example 1

[0042] This embodiment discloses a method for monitoring the online safe operation status of a steam turbine's low-pressure cylinder at zero output, including:

[0043] Acquire the operating parameters of the low-pressure cylinder, the operating parameters of the intermediate-pressure cylinder related to the cylinder cut, and the operating parameters of the auxiliary equipment during the cylinder cut process;

[0044] Based on the operating parameters of the low-pressure cylinder, determine the basic operating state of the low-pressure cylinder, the blowing state of the low-pressure cylinder, the water erosion state of the last stage blades, the temperature field and stress field of the cylinder, rotor and blades, and the dynamic stress distribution and dynamic stress characteristic value of the blades.

[0045] Based on the temperature and stress fields of the cylinder and rotor, determine the low-cycle fatigue damage cycles, life loss rate, and life damage accumulation of the cylinder and rotor.

[0046] Based on the dynamic stress distribution and dynamic stress characteristic values ​​of the blade, flutter analysis is performed on the blade to determine the risk of flutter and the flutter avoidance rate.

[0047] Determine the operating status of the intermediate pressure cylinder and the related auxiliary equipment based on the relevant operating parameters of the intermediate pressure cylinder and the related auxiliary equipment.

[0048] Operational guidance is provided based on the basic operating status of the low-pressure cylinder, its life loss rate, water erosion status, the operating status of the intermediate-pressure cylinder, the operating status of related auxiliary equipment, and the results of flutter analysis.

[0049] The basic operating state of the low-pressure cylinder refers to comparing the acquired operating parameters with the corresponding parameter thresholds to determine whether each operating parameter exceeds the limit, and then judging the basic operating state of the low-pressure cylinder. When a certain operating parameter exceeds the limit, the basic operating state is judged to be abnormal, specifically, the operating parameter in the basic operating state is abnormal.

[0050] The process of obtaining the water erosion state of the last-stage blade is as follows:

[0051] By obtaining the low-pressure cylinder operating parameters, the flow separation height of the last-stage blades and the moisture content in the last-stage steam are determined; by the moisture content in the last-stage steam and the flow separation height of the last-stage blades, the water erosion state of the last-stage blades is determined.

[0052] Specifically, the acquired low-pressure cylinder operating parameters include changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, changes in low-pressure cylinder extraction parameters, changes in cylinder metal temperature, measured values ​​at the final stage temperature measuring point, final stage water injection flow rate, water injection temperature, water injection pressure, nozzle operating status, and final stage exhaust pressure of the low-pressure cylinder.

[0053] By analyzing the changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, changes in low-pressure cylinder extraction parameters, changes in cylinder metal temperature, measured values ​​of the final stage temperature measuring point, and the final stage exhaust pressure of the low-pressure cylinder, the blowing state of the low-pressure cylinder, the temperature field and stress field of the cylinder, rotor and blades, as well as the dynamic stress distribution and dynamic stress characteristic value of the blades during the cylinder cutting process are determined.

[0054] The water erosion state of the final stage blades is determined by measuring the final stage water flow rate, water temperature, water pressure, nozzle operating status, and final stage exhaust pressure of the low-pressure cylinder.

[0055] In practical implementation, the changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, low-pressure cylinder extraction parameters, cylinder metal temperature, and final stage temperature measurement points during cylinder cutting are analyzed using a thermal-fluid coupling numerical calculation model of the low-pressure cylinder's flow path under low flow rate. This model determines the unstable flow characteristics of steam at each stage of the low-pressure cylinder. Based on these unstable flow characteristics, the backflow, separation, and vortex generation of steam in the final, second, and third stages of the low-pressure cylinder are determined. This determines the blower state of the low-pressure cylinder and the location where the blower operation occurs. The blower heat is calculated, thus determining the blower location and blower heat of the cylinder, rotor, and blades.

[0056] In this embodiment, after obtaining the blower position and blower heat of the cylinder, rotor, and blades, fluid-structure interaction analysis is performed on the cylinder, rotor, and blades respectively based on the blower position and blower heat of the cylinder, rotor, and blades to determine the temperature field and stress field of the cylinder, rotor, and blades.

[0057] Specifically, based on the constructed thermal-fluid coupling numerical calculation model, this embodiment establishes a fluid-structure coupling numerical calculation model for the flow passage of the low-pressure cylinder under low flow rate. By using the blower position and blower heat of the cylinder, rotor, and blades, and the fluid-structure coupling numerical calculation model, fluid-structure coupling analysis is performed on the cylinder, rotor, and blades to obtain the heat transfer coefficient of the flow passage in the corresponding parts. Then, based on the heat transfer coefficient of each part, the temperature field and stress field of the corresponding part are calculated.

[0058] Subsequently, based on the temperature and stress fields of the cylinder, rotor, and blades, the locations of maximum temperature and stress in the cylinder, rotor, and blades are determined, which are the most dangerous parts of the cylinder, rotor, and blades.

[0059] The most dangerous parts of the cylinder and rotor are analyzed. Based on the stress and strain at the most dangerous parts of the cylinder and rotor during cylinder cutting, the low-cycle fatigue damage cycles and life loss rates of the rotor and cylinder are determined. The specific process is as follows:

[0060] Determine the stress and strain at the most dangerous parts of the cylinder and rotor during cylinder cutting;

[0061] Based on the stress and strain at the most dangerous parts of the cylinder and rotor during cylinder cutting, the number of low-cycle fatigue damage cycles is determined. The number of low-cycle fatigue damage cycles is the number of cylinder cutting cycles in which the stress and strain at the most dangerous parts of the cylinder and rotor exceed a set threshold during cylinder cutting. One cylinder cutting cycle is the period from the start of cylinder cutting to the end of cylinder cutting, when the cylinder is restored to the operating state before the start of cylinder cutting.

[0062] The life loss rate is determined based on the number of low-cycle fatigue damage cycles, where the life loss rate is the ratio of the number of low-cycle fatigue damage cycles to the allowable number of low-cycle fatigue damage cycles.

[0063] This embodiment also adds up the life damage of each cylinder cutting cycle in the cylinder or rotor's operating history to obtain the cumulative life damage of the cylinder or rotor.

[0064] The process of obtaining the dynamic stress distribution and characteristic values ​​of the blade is as follows: Based on the constructed fluid-structure interaction numerical calculation model of the flow passage part under low flow rate of the low-pressure cylinder, a modal analysis calculation model of the blade is established; according to the obtained cooling steam flow rate, cooling steam temperature, cooling steam pressure, steam flow rate change during cylinder insertion and removal, low-pressure cylinder extraction parameter change during cylinder insertion and removal, cylinder metal temperature change during cylinder insertion and removal, measured values ​​of the last stage temperature measuring point, exhaust pressure, and blade material property information, as well as the blade modal analysis calculation model, the blade modes are analyzed to determine the blade vibration stress and unstable flow characteristics; based on the unstable flow characteristics of the blade, the steam backflow, separation, and vortex generation of the last stage, the last second stage, and the last third stage are analyzed and determined, and the stress generated by the unstable flow of the blade is determined. The stress generated by the unstable flow is coupled with the vibration stress to determine the unstable flow state of the blade, and then the dynamic stress distribution and characteristic values ​​of the blade are determined.

[0065] Based on the dynamic stress distribution and characteristic values ​​of the blades, flutter analysis is performed to determine the risk of flutter and the flutter avoidance rate. Specifically:

[0066] The ratio of the dynamic stress characteristic value of the blade to the dynamic stress characteristic value when the blade flutters is calculated to obtain the risk of blade flutter. The closer the ratio is to 1, the greater the possibility of flutter. When it equals 1, the blade flutter is determined.

[0067] The difference between the steam flow rate and the steam flow rate corresponding to the blade flutter is calculated. The ratio of this difference to the steam flow rate corresponding to the blade flutter is the flutter avoidance rate.

[0068] The dynamic stress characteristic value and the corresponding steam flow rate when the blades flutter are calculated based on the low-pressure cylinder operating parameter data when the blades flutter.

[0069] This embodiment determines the water erosion process of the blade as follows:

[0070] By analyzing parameters such as the final stage water spray flow rate, spray temperature, spray pressure, nozzle operating status, and final stage exhaust pressure of the low-pressure cylinder, heat balance calculations are performed before and after the low-pressure cylinder receives cooling steam from the final stage water spray, obtaining the thermodynamic state of the steam mixture at the final stage steam outlet of the low-pressure cylinder. Based on the thermodynamic state of the steam mixture, the steam humidity and moisture content of the steam mixture at the final stage steam outlet of the low-pressure cylinder are determined. Through the steam humidity and moisture content and the constructed heat-fluid coupling numerical calculation model, unsteady flow analysis of the final stage is performed to determine the return flow rate of the cooling steam mixed with moisture and the deflection height of the final stage blades. Based on the moisture content in the steam and the deflection height of the blades, the water erosion state of the final stage blades is determined.

[0071] In this embodiment, the thermal-fluid coupling numerical calculation model, the fluid-structure interaction numerical calculation model, and the blade modal analysis calculation model all use the calculation models provided by the simulation software. When the corresponding input data is input, the thermal-fluid coupling analysis results, the fluid-structure interaction analysis results, and the blade modal analysis results are automatically output.

[0072] The thermal-fluid coupling numerical calculation model takes the changes in cooling steam flow rate, low-pressure cylinder extraction parameters, cylinder metal temperature, and final stage temperature measurement values ​​as inputs during cylinder cutting, and outputs the unstable flow characteristics of steam at each stage.

[0073] The fluid-structure interaction numerical calculation model takes the changes in cooling steam flow rate, cooling steam pressure, low-pressure cylinder extraction parameters, cylinder metal temperature, final stage temperature measurement points, and exhaust pressure as inputs during cylinder cutting, and outputs heat transfer coefficient, temperature field, and stress field.

[0074] The modal analysis calculation model of the blade takes the cooling steam flow rate, cooling steam temperature, cooling steam pressure, steam flow rate change during cylinder insertion and removal, low-pressure cylinder extraction parameter change during cylinder insertion and removal, cylinder metal temperature change during cylinder insertion and removal, final stage temperature measurement value, exhaust pressure, and blade material property information as inputs, and outputs the blade vibration stress, dynamic stress distribution, and dynamic stress characteristic value.

[0075] This embodiment also acquires vibration data of the cylinder cut-off bypass pipeline and the original low-pressure cylinder steam inlet bypass. By acquiring the vibration data of the cylinder cut-off bypass pipeline and the original low-pressure cylinder steam inlet bypass, the vibration of the cylinder cut-off bypass pipeline and the original low-pressure cylinder steam inlet bypass is analyzed, thus realizing vibration monitoring of the cylinder cut-off bypass pipeline and the original low-pressure cylinder steam inlet bypass.

[0076] This embodiment also acquires the relevant operating parameters of the intermediate pressure cylinder and the relevant auxiliary machine operating parameters related to cylinder cutting, and monitors the operating status of the intermediate pressure cylinder and the relevant auxiliary machine through the relevant operating parameters of the intermediate pressure cylinder and the relevant auxiliary machine.

[0077] The acquired operating parameters of the intermediate-pressure cylinder include the intermediate-pressure cylinder exhaust parameters, the parameters of the last two stages of regenerative extraction steam in the intermediate-pressure cylinder, the vibration of the intermediate-low pressure connecting pipe, the vibration of the cooling steam pipeline, and the heating parameters. Based on the intermediate-pressure cylinder exhaust parameters, the parameters of the last two stages of regenerative extraction steam in the intermediate-pressure cylinder, the vibration of the intermediate-low pressure connecting pipe, the vibration of the cooling steam pipeline, and the heating parameters, the intermediate-pressure cylinder is monitored for exceeding the limits of the intermediate-pressure cylinder exhaust parameters, exceeding the limits of the differential pressure of the last two stages of regenerative extraction steam in the intermediate-pressure cylinder, the vibration of the intermediate-low pressure connecting pipe, the vibration of the cooling steam pipeline, and the heating parameters.

[0078] Intermediate pressure cylinder exhaust parameter over-limit monitoring refers to determining whether the intermediate pressure cylinder exhaust parameters exceed the exhaust threshold.

[0079] Monitoring of excessive pressure difference between the last two stages of regenerative extraction steam in intermediate pressure cylinder refers to determining the pressure difference between the last two stages of regenerative extraction steam in intermediate pressure cylinder before and after cylinder cut-off based on the parameters of the last two stages of regenerative extraction steam in intermediate pressure cylinder, and judging whether the pressure difference between the last two stages of regenerative extraction steam in intermediate pressure cylinder is greater than the pressure difference threshold.

[0080] The relevant auxiliary equipment operating parameters obtained include condenser vacuum, condensate dissolved oxygen, condensate flow rate, and low-pressure cylinder bearing operating status. These parameters are used to monitor condenser vacuum, condensate dissolved oxygen, condensate flow rate, and low-pressure cylinder bearing operating status.

[0081] This embodiment also provides operational guidance based on the obtained life loss rate, life damage accumulation, water erosion status, blower status, intermediate pressure cylinder operating status, related auxiliary machine operating status, and flutter analysis results. When the basic operating status is abnormal, or when the life loss rate of the low-pressure cylinder rotor or cylinder exceeds the loss rate threshold, the flutter risk level exceeds the risk level threshold, the water erosion exceeds the set level, or the blower status exceeds the set blower level, operational adjustment suggestions are given. After making corresponding adjustments to the turbine unit according to the suggestions, the normal operation of the turbine unit can be guaranteed.

[0082] In specific implementation, such as Figure 1 As shown, this embodiment uses a low-pressure cylinder zero-output cylinder switching and cylinder-starting process data recording module to acquire basic thermodynamic system data of the low-pressure cylinder at zero output, load before and after cylinder switching, cylinder temperature, last stage measuring point temperature, steam parameters, steam flow rate, pipeline vibration, extraction steam temperature, extraction steam pressure, intermediate-pressure cylinder exhaust temperature, extraction steam parameters of the last two stages of intermediate-pressure cylinder, heating parameters, cylinder switching and cylinder-starting time, etc., for condition analysis, fatigue damage, life loss analysis, blade flutter analysis, blade water erosion analysis, blower condition analysis, etc., and determines the basic operating state of the low-pressure cylinder.

[0083] The cooling steam analysis module acquires data on changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, changes in low-pressure cylinder extraction parameters, changes in cylinder metal temperature, and measured values ​​at the final stage temperature measurement point during cylinder cutting. The blower status analysis module analyzes these parameters acquired by the cooling steam analysis module to determine the blower location and calculate the blower heat.

[0084] The final stage water spray analysis module acquires the final stage water spray flow rate, water spray temperature, water spray pressure, nozzle operating status, and low-pressure cylinder final stage exhaust pressure. The final stage water erosion monitoring module analyzes the data acquired by the final stage water spray analysis module to determine the severity of final stage water erosion.

[0085] The temperature, stress, and life loss analysis module of the low-pressure cylinder rotor and cylinder analyzes the changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, changes in low-pressure cylinder extraction parameters, changes in cylinder metal temperature, measured values ​​of the final stage temperature measuring point, and blower heat during the cylinder cutting process, and determines the temperature field, stress field, fatigue damage cycles, life loss rate, and life damage accumulation of the rotor and cylinder.

[0086] The blade modal and stress analysis module analyzes the changes in cooling steam flow rate, cooling steam temperature, cooling steam pressure, low-pressure cylinder extraction parameters, cylinder metal temperature, final stage temperature measurement points, and exhaust pressure during cylinder cutting to determine the blade's temperature field, stress field, dynamic stress distribution, and dynamic stress characteristic values.

[0087] The blade flutter analysis and monitoring module analyzes the dynamic stress of the blade to determine the risk of blade flutter and the flutter avoidance rate.

[0088] The intermediate pressure cylinder exhaust parameters, the last two stages of regenerative extraction steam parameters, the vibration of the intermediate and low pressure connecting pipes, the vibration of the cooling steam pipeline, and the heating parameters are obtained through the intermediate pressure cylinder related parameter monitoring module. It also performs monitoring of the intermediate pressure cylinder exhaust parameters exceeding limits, monitoring of the pressure difference of the last two stages of regenerative extraction steam exceeding limits, vibration detection of the intermediate and low pressure connecting pipes, vibration monitoring of the cooling steam pipeline, and monitoring of heating parameters.

[0089] The condenser vacuum monitoring, condensate dissolved oxygen monitoring, condensate flow monitoring, and low-pressure cylinder bearing monitoring are performed through relevant auxiliary equipment safety status analysis modules.

[0090] The guidance module provides corresponding guidance and suggestions based on monitoring data and analysis results.

[0091] In this embodiment, all parameters acquired are transmitted to the field operation data acquisition unit and then sent to the central data processing unit. Each analysis module performs data analysis through the central data processing unit to obtain data analysis results. The acquired parameters and the results obtained from the analysis are sent to the display output unit and the historical data storage unit. The display output unit displays the data, and the historical data storage unit stores the data, recording the data for each cylinder cut-off and cylinder insertion, running time, historical count, historical lifespan accumulation, etc.

[0092] The method disclosed in this embodiment can be used for low-pressure cylinder zero-output units of various capacities and parameters, as well as low-pressure cylinder micro-output units.

[0093] This embodiment discloses a method that monitors operating parameters, establishes an analytical model to analyze the temperature and stress of the low-pressure cylinder rotor and cylinder, determines the life loss rate of the rotor and cylinder, and determines the cumulative life damage during frequent cylinder cut-off operation. It monitors the blade modes in real time, detecting phenomena such as blade flutter and erosion, and determines the flutter avoidance rate, flutter risk, and erosion severity. It monitors the exhaust parameters of the intermediate-pressure cylinder and the extraction parameters of the last two stages of recovery steam to ensure the safety of the intermediate-pressure cylinder. It also monitors the vibration of the intermediate- and low-pressure connecting pipes, the cylinder cut-off bypass cooling steam pipes, and the low-pressure cylinder bearing vibration in real time. Furthermore, it monitors the operating status of related auxiliary equipment in real time. This improves the operational safety of turbine units retrofitted to zero output in the low-pressure cylinder; real-time data monitoring and control provide operational guidance.

[0094] like Figure 2 As shown, when the method disclosed in this embodiment is used for monitoring the zero-output operation of the low-pressure cylinder of a 300MW unit turbine, the obtained rotor temperature distribution map, stress distribution map, cylinder temperature distribution map, stress distribution map, and blade stress distribution map are respectively shown in the figure. Figure 3-7 As shown. Based on this, the lifetime loss rate, lifetime damage accumulation, flutter avoidance rate, and flutter risk were obtained, which are consistent with the actual situation, verifying the accuracy of the method disclosed in this embodiment.

[0095] Example 2

[0096] In this embodiment, a zero-output online safety operation status monitoring system for the low-pressure cylinder of a steam turbine is disclosed, comprising:

[0097] The low-pressure cylinder zero-output cylinder cutting and cylinder insertion process data recording module is used to acquire the low-pressure cylinder operating parameters, the intermediate-pressure cylinder related operating parameters and the related auxiliary machine operating parameters during the cylinder cutting process, and to determine the basic operating status of the low-pressure cylinder based on the low-pressure cylinder operating parameters;

[0098] The blower status analysis module is used to determine the blower status of the low-pressure cylinder based on the operating parameters of the low-pressure cylinder.

[0099] The final stage water erosion monitoring module is used to determine the water erosion status of the final stage blades based on the operating parameters of the low-pressure cylinder.

[0100] The low-pressure cylinder rotor and cylinder temperature, stress, and life loss analysis module is used to determine the temperature field and stress field of the cylinder and rotor during cylinder cutting based on the low-pressure cylinder operating parameters; and to determine the low-cycle fatigue damage cycles, life loss rate, and life damage accumulation of the cylinder and rotor based on the temperature field and stress field of the cylinder and rotor.

[0101] The blade modal and stress analysis module is used to determine the temperature field and stress field of the blade, as well as the dynamic stress distribution and dynamic stress characteristic value of the blade, by acquiring the low-pressure cylinder operating parameters.

[0102] The blade flutter analysis and monitoring module is used to analyze the blade flutter based on the dynamic stress distribution and dynamic stress characteristic values ​​of the blade, and to determine the risk of blade flutter and the flutter avoidance rate.

[0103] The intermediate pressure cylinder related parameter monitoring and analysis module is used to monitor the operating status of the intermediate pressure cylinder based on relevant operating parameters. Specifically, based on the acquired intermediate pressure cylinder exhaust parameters, intermediate pressure cylinder last two-stage regenerative extraction steam parameters, intermediate and low pressure connecting pipe vibration, cooling steam pipeline vibration, and heating parameters, the module monitors the intermediate pressure cylinder exhaust parameters exceeding limits, intermediate pressure cylinder last two-stage regenerative extraction steam pressure difference exceeding limits, intermediate and low pressure connecting pipe vibration, cooling steam pipeline vibration, and heating parameters.

[0104] The auxiliary equipment safety status analysis module is used to monitor the operating status of relevant auxiliary equipment based on relevant auxiliary equipment operating parameters. Specifically, it monitors condenser vacuum, condensate dissolved oxygen, condensate flow rate, and low-pressure cylinder bearing operating status by acquiring parameters such as condenser vacuum, condensate dissolved oxygen, condensate flow rate, and low-pressure cylinder bearing.

[0105] The operation guidance module provides operational guidance based on the basic operating status, life loss rate, water erosion status, intermediate cylinder operating status, related auxiliary machine operating status, and chatter analysis results of the low-pressure cylinder. When the basic operating status is abnormal, or the life loss rate of the low-pressure cylinder rotor or cylinder exceeds the loss rate threshold, or the chatter risk level exceeds the risk level threshold, it provides operational adjustment suggestions.

[0106] Example 3

[0107] In this embodiment, an electronic device is disclosed, including a memory and a processor, as well as computer instructions stored in the memory and running on the processor. When the processor executes the computer instructions, it completes the steps described in the online safe operation status monitoring method for zero output of a steam turbine low-pressure cylinder disclosed in Embodiment 1.

[0108] Example 4

[0109] In this embodiment, a computer-readable storage medium is disclosed for storing computer instructions. When the computer instructions are executed by a processor, they complete the steps described in the online safe operation status monitoring method for zero output of a steam turbine low-pressure cylinder disclosed in Embodiment 1.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for monitoring the on-line safe operation state of a low-pressure cylinder of a steam turbine with zero output, characterized in that, The method comprises the following steps: acquiring the operation parameters of the low-pressure cylinder, the operation parameters of the medium-pressure cylinder related to the cylinder cutting, and the operation parameters of the related auxiliary machines during the cylinder cutting process; determining the basic operation state of the low-pressure cylinder according to the operation parameters of the low-pressure cylinder, determining the blast state of the low-pressure cylinder, the water erosion state of the last-stage blade, the temperature field and stress field of the cylinder, rotor and blade, and the dynamic stress distribution and characteristic value of the blade; determining the low-cycle fatigue damage cycles, life consumption rate and life damage accumulation of the cylinder and rotor according to the temperature field and stress field of the cylinder and rotor; carrying out flutter analysis on the blade according to the dynamic stress distribution and characteristic value of the blade, and determining the risk degree of the blade flutter and the flutter avoidance rate; monitoring the operation state of the medium-pressure cylinder and auxiliary machines according to the operation parameters of the medium-pressure cylinder and the operation parameters of the related auxiliary machines; carrying out operation guidance according to the basic operation state of the low-pressure cylinder, the life consumption rate, the water erosion state, the operation state of the medium-pressure cylinder, the operation state of the related auxiliary machines and the flutter analysis result.

2. The method for monitoring the on-line safe operation state of the zero output of the low-pressure cylinder of a steam turbine according to claim 1, characterized in that, determining the most dangerous position of the cylinder and rotor according to the temperature field and stress field of the cylinder and rotor; determining the low-cycle fatigue damage cycles and life consumption rate of the rotor and cylinder according to the stress and strain of the most dangerous position of the cylinder and rotor during the cylinder cutting.

3. The method for monitoring the on-line safe operation state of the zero output of the low-pressure cylinder of a steam turbine according to claim 2, characterized in that, determining the low-cycle fatigue damage cycles according to the stress and strain of the most dangerous position of the cylinder and rotor during the cylinder cutting, wherein the low-cycle fatigue damage cycles are the cylinder cutting cycles in which the stress and strain of the most dangerous position of the cylinder and rotor exceed the set threshold value; determining the life consumption rate according to the low-cycle fatigue damage cycles.

4. The method of claim 1, wherein, adding the life damage of each cylinder cutting cycle in the operation history of the cylinder or rotor to obtain the life damage accumulation of the cylinder or rotor.

5. The method of claim 1, wherein, The water erosion state of the last-stage blade is determined according to the water content in the last-stage steam and the water erosion state of the last-stage blade.

6. The method of claim 1, wherein, The risk degree of the blade flutter is obtained by calculating the ratio of the dynamic stress characteristic value of the blade to the dynamic stress characteristic value of the blade when the flutter occurs. The difference between the steam flow and the corresponding steam flow when the blade flutter occurs is calculated, and the ratio of the difference to the corresponding steam flow when the blade flutter occurs is the flutter avoidance rate.

7. The method of claim 1, wherein, The vibration data of the cylinder cutting bypass pipeline and the vibration data of the original low-pressure cylinder inlet bypass are also acquired, and the vibration of the cylinder cutting bypass pipeline and the original low-pressure cylinder inlet bypass is analyzed according to the acquired vibration data.

8. A low-pressure cylinder zero-output on-line safe operation state monitoring system for a steam turbine, characterized in that, The method comprises the following steps: a low-pressure cylinder zero-output cylinder cutting and cylinder throwing process data recording module is used to acquire the operation parameters of the low-pressure cylinder, the operation parameters of the medium-pressure cylinder related to the cylinder cutting, and the operation parameters of the related auxiliary machines during the cylinder cutting process; a blast state analysis module is used to determine the blast state of the low-pressure cylinder according to the operation parameters of the low-pressure cylinder; a last-stage water erosion monitoring module is used to determine the water erosion state of the last-stage blade according to the operation parameters of the low-pressure cylinder; A low-pressure cylinder rotor, cylinder temperature, stress, and life consumption analysis module is configured to determine a temperature field and a stress field of the cylinder and the rotor during a cylinder cutting process according to low-pressure cylinder operating parameters; and determine a low-cycle fatigue damage cycle, a life consumption rate, and a life damage accumulation of the cylinder and the rotor according to the temperature field and the stress field of the cylinder and the rotor. A blade modal and stress analysis module is configured to determine a temperature field and a stress field of the blade, and a dynamic stress distribution and a dynamic stress eigenvalue of the blade by acquiring low-pressure cylinder operating parameters. A blade flutter analysis monitoring module is configured to perform a flutter analysis on the blade according to the dynamic stress distribution and the dynamic stress eigenvalue of the blade, and determine a flutter risk degree and a flutter avoidance rate of the blade. A medium-pressure cylinder related parameter monitoring analysis module is configured to monitor a medium-pressure cylinder operating state according to medium-pressure cylinder related operating parameters. An auxiliary machine safety state analysis module is configured to monitor related auxiliary machine operating states according to related auxiliary machine operating parameters. An operation guidance module is configured to perform operation guidance according to the life consumption rate, the water erosion state, the medium-pressure cylinder operating state, the related auxiliary machine operating states, and the flutter analysis results.

9. An electronic device, comprising: A computer program product comprising a memory and a processor, and computer instructions stored in the memory and run on the processor, when the computer instructions are run by the processor, the steps of the method for monitoring an online safe operating state of a low-pressure cylinder of a steam turbine with zero output according to any one of claims 1-7 are completed.

10. A computer-readable storage medium, characterized in that, A computer program product for storing computer instructions, when the computer instructions are executed by a processor, the steps of the method for monitoring an online safe operating state of a low-pressure cylinder of a steam turbine with zero output according to any one of claims 1-7 are completed.

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