Stress monitoring and sensor arrangement method for pressure steel pipes in pumped storage power stations

Abstract

This invention discloses a method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations, relating to the field of structural safety monitoring technology for pumped storage power stations. The method includes: establishing a three-dimensional simulation model of the pressure steel pipe and the unit flow channel based on operating parameters; obtaining the stress field under all operating conditions using fluid-structure interaction analysis; extracting extreme stresses, spatial coordinates, and principal stress directions at special cross-sections to construct a special location database containing extreme point trajectories; uniformly arranging three sets of resistance strain sensors circumferentially around the cross-section according to the database results, with each set of three sensors forming a strain rosette and oriented according to the principal stress direction to achieve matching of the monitoring direction with the principal stress axis; comparing real-time monitoring results with the database range, triggering calibration and early warning when limits are exceeded, and outputting a maintenance priority list. This achieves adaptive directional monitoring, anomaly detection, and dynamic maintenance of the pressure steel pipe under all operating conditions, improving operational safety and targeted maintenance.

Description

Technical Field

[0001] This invention relates to the field of structural safety monitoring technology for pumped storage power stations, and in particular to a method for stress monitoring and sensor arrangement in the pressure steel pipes of pumped storage power stations. Background Technology

[0002] Pumped storage power stations, as crucial peak-shaving and energy storage facilities in the power system, are subjected to the long-term effects of high head, large flow rates, and frequent start-ups and shutdowns in their water conveyance systems. The pressure steel pipe, a key pressure-bearing component of the water conveyance system, experiences complex fluid-structure interaction under different operating conditions. Its stress distribution fluctuates significantly with changes in operating parameters such as upstream and downstream water levels, guide vane opening, and unit speed. With increasing service life, fatigue accumulation and structural damage can easily occur in localized areas of the pressure steel pipe, potentially leading to leakage or even instability and failure, directly threatening the power station's operational safety and power supply reliability. Therefore, achieving accurate stress monitoring and dynamic safety assessment of the pressure steel pipe under all operating conditions is one of the core issues in the current operation and maintenance of pumped storage power stations.

[0003] In existing technologies, conventional strain gauge placement methods are mostly based on experience, deploying a limited number of strain sensors at locations such as elbows, welds, and diameter changes. The monitoring results often fail to comprehensively reflect the true stress changes under all operating conditions. Furthermore, existing structural fatigue assessment methods primarily rely on rainflow counting based on stress time histories and the Miner linear cumulative damage model. However, these methods only perform statistical analysis after operation, making it difficult to link with real-time monitoring events and respond quickly to sudden abnormal conditions. On the other hand, existing technologies lack integration with simulation databases in sensor placement; the placement positions and orientations are often fixed, making it difficult to adaptively adjust for principal stress directions and extreme point trajectories, resulting in insufficient monitoring accuracy and reliability. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations, which solves the problems of existing stress monitoring technologies for pressure steel pipes in pumped storage power stations, such as reliance on experience-based point placement, unclear threshold settings, and disconnect between monitoring and maintenance in terms of sensor arrangement, anomaly detection mechanism, and damage accumulation assessment.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations, which includes: establishing a three-dimensional simulation model of the pressure steel pipe and the flow channel of the unit based on the operating condition parameters collected by the operation monitoring system of the pumped storage power station; calculating the pressure distribution of the flow channel based on the set of operating conditions; and obtaining the stress field under each operating condition through fluid-structure interaction analysis. The extreme stress and spatial coordinates of special cross sections are extracted from the stress field, and the principal stress directions are recorded simultaneously to form a special location database containing a set of stress characteristic parameters, which is used to guide the monitoring layout. Based on the database results, three sets of resistance strain sensors are arranged at each special cross section, and the three sets of sensors form a strain rose and are oriented in accordance with the principal stress direction. By comparing real-time sensor data with database entries, calibration and early warning are triggered when the monitored value exceeds the discrimination threshold. Abnormal events are used as weighted inputs for damage accumulation, and maintenance priorities are output, thereby realizing adaptive directional monitoring, discrimination, and dynamic maintenance of pressure steel pipes under all working conditions.

[0007] As a preferred embodiment of the method for monitoring the stress of the pressure steel pipe and arranging sensors in the pumped storage power station described in this invention, the operating parameters include: upstream water level, downstream water level, guide vane opening, and unit speed. The calculation of the pressure distribution in the flow channel includes, in the three-dimensional simulation model, performing fluid numerical solution of the water conveyance channel based on the Reynolds time-averaged N-S equation, and obtaining the pressure distribution results of the inner wall of the pressure steel pipe under different operating conditions. The process of obtaining the stress field under each working condition includes applying the pressure distribution result as a boundary load directly to the pressure steel pipe structure of the three-dimensional simulation model, and solving it using the fluid-structure interaction finite element analysis method to obtain the stress field of the pressure steel pipe under each operating condition.

[0008] As a preferred embodiment of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations according to the present invention, the formation of the special location database includes: determining a set of special cross-sections in the water conveyance system in the stress field of each operating condition; analyzing the special cross-sections, extracting extreme stresses and their spatial coordinates on the outer surface of the pressure steel pipe, and simultaneously recording the principal stress directions; establishing special location database entries using the operating conditions and cross-sections as indexes; and serializing and storing the changes in the spatial coordinates with the operating conditions to obtain the extreme point trajectory, which is used to guide the subsequent arrangement and orientation of sensors. The set of special sections includes variable diameter sections, sections before and after bifurcated pipes, and the location of maximum stress along the line; the entries include the extreme stress, spatial coordinates, and principal stress direction information.

[0009] As a preferred embodiment of the method for stress monitoring and sensor arrangement of pressure steel pipe in pumped storage power stations according to the present invention, the arrangement of three sets of resistance strain sensors includes setting three sets of resistance strain sensors at equal arc length intervals in the circumferential direction of each special cross section, and each set of resistance strain sensors is attached to the surface corresponding to the extreme stress coordinates recorded in the special location database.

[0010] As a preferred embodiment of the stress monitoring and sensor arrangement method for pressure steel pipes in pumped storage power stations described in this invention, the three sets of sensors forming a strain rose includes three resistance strain sensors arranged at equal angular intervals in each set, wherein the first sensor is oriented along the principal stress direction, and the other two sensors are oriented at equal angles relative to the principal stress direction in the circumferential direction; the three sets of resistance strain sensors are oriented and corrected based on the direction angle determined by the principal stress direction under different operating conditions, and the priority application sector is determined based on the distribution results of the extreme point trajectory to ensure that the sensor arrangement covers the high-frequency occurrence area of ​​the principal stress.

[0011] As a preferred embodiment of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations according to the present invention, the step of comparing real-time sensor data with entries in a special location database includes comparing the monitored principal stress with the stress range recorded in the special location database, and triggering sensor calibration or early warning when the monitoring result exceeds the stress range.

[0012] As a preferred embodiment of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations described in this invention, the step of using abnormal events as weighted inputs for damage accumulation includes classifying triggered abnormal events according to their severity, wherein events triggered by minor over-limits are designated as yellow light events, indicating entry into a key monitoring state, and events triggered by severe over-limits are designated as red light events, indicating entry into a high-risk state, and the yellow light events and red light events are used to weight and correct the accumulated damage results; The output maintenance priority includes sorting each special section according to the corrected damage results to form a maintenance priority list.

[0013] Secondly, the present invention provides a stress monitoring and sensor arrangement system for pressure steel pipes in pumped storage power stations, including: a simulation modeling module, used to establish a three-dimensional simulation model of the pressure steel pipe and the flow channel of the unit based on the operating parameters collected by the operation monitoring system, and to obtain the stress field under each operating condition through fluid-structure interaction analysis; The special location database module is used to extract the extreme stress and spatial coordinates of special sections in the stress field, and simultaneously record the principal stress direction to form a database entry containing a set of stress characteristic parameters, and store the trajectory of extreme points. The sensor arrangement module is used to uniformly arrange three sets of resistance strain sensors in the circumferential direction of each special cross section according to the results of the special location database, and to make each set form a strain rose structure and be oriented according to the principal stress direction. The data comparison and discrimination module is used to compare the real-time monitoring data of the sensor with the special location database entries, and to trigger sensor calibration or warning when the monitoring result exceeds the stress range of the database. The damage accumulation and weighting module is used to classify abnormal events into mild and severe exceedances, forming yellow light events and red light events respectively, and using the events as weighting factors to correct the fatigue damage accumulation results; The maintenance priority module is used to sort special sections based on the corrected damage results and output a maintenance priority list to guide the dynamic maintenance of pressure steel pipes.

[0014] Thirdly, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein when the computer program is executed by the processor, it implements any step of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in the first aspect of the present invention.

[0015] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in the first aspect of the present invention.

[0016] The beneficial effects of this invention are as follows: By establishing a three-dimensional simulation model including the water intake steel pipe, tailrace steel pipe, and unit flow channel, and performing fluid-structure interaction analysis based on a set of operating conditions, full-range stress distribution results can be obtained under different operating conditions. Based on this, extreme stresses, spatial coordinates, and principal stress directions of special cross-sections are extracted to form a database and store extreme point trajectories, providing quantitative guidance for sensor placement. Sensors are uniformly distributed circumferentially on special cross-sections, with three sensors in each group forming a strain rosette and oriented according to the principal stress direction, ensuring that the real-time monitoring direction is consistent with the principal stress axis, thereby improving data reliability. Real-time monitoring results are compared with the stress range in the database. When the monitored value exceeds a set threshold, calibration and early warning are automatically triggered, enabling timely identification of potential anomalies. Abnormal events are classified into yellow and red light categories, and a fatigue damage accumulation model is introduced for weighted correction, linking damage assessment with real-time anomaly monitoring. The final output maintenance priority list can dynamically guide maintenance strategies, significantly improving the operational safety of the steel pipe and the targeted nature of maintenance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the stress monitoring and sensor arrangement method for pressure steel pipes in pumped storage power stations. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0022] Reference Figure 1 This is one embodiment of the present invention, which provides a method for stress monitoring and sensor arrangement in the pressure steel pipe of a pumped storage power station, including the following steps: S1: Based on the operating condition parameters collected by the pumped storage power station operation monitoring system, a three-dimensional simulation model of the pressure steel pipe and the unit flow channel is established. The pressure distribution of the flow channel is calculated based on the set of operating conditions, and the stress field under each operating condition is obtained through fluid-structure interaction analysis.

[0023] Based on the operating condition parameters collected by the pumped storage power station operation monitoring system, an operating condition set is constructed: in, This represents a collection of operating conditions; Indicates the first Each operating condition; Indicates the first Upstream water level under specific operating conditions; Indicates the first Downstream water level under specific operating conditions; Indicates the first Guide vane opening under various operating conditions; Indicates the first Unit speed under various operating conditions; Indicates an index.

[0024] Based on this, a three-dimensional simulation model including the pressure steel pipe and the unit flow channel was established using the finite element method coupled with the finite volume method. The model consists of a fluid domain and a structural domain. The fluid domain covers the water intake and tailrace pipes and the flow channel area, while the structural domain covers the entire length of the pressure steel pipe.

[0025] During geometric modeling, elbows, reducers, bifurcations, and weld locations are locally meshed with refined meshes, making their element size 1 / 3 of that of conventional elements to ensure the capture of local extreme stresses. This is applied to each working condition. Boundary conditions are set in the fluid domain.

[0026] The inlet pressure is calculated from the upstream water level: The outlet pressure is calculated from the downstream water level: in, Indicates working conditions The inlet pressure below; Indicates the density of water; Represents gravitational acceleration; Indicates working conditions Export pressure under pressure.

[0027] The fluid domain was numerically solved using the Reynolds-averaged Navier-Stokes equations (RANS) to obtain the pressure distribution function on the inner wall: The pressure distribution The inner wall of the steel pipe projected onto the 3D simulation model is used as the boundary load of the structural domain. The stress field under various working conditions is calculated using the fluid-structure interaction finite element analysis method: in, Indicates working conditions Position of the inner wall of the lower steel pipe Pressure value; Represents the spatial coordinates of the inner wall of the steel pipe; Represents the coordinate domain of the inner wall of the steel pipe; Represent the space of real numbers; Indicates working conditions In position The stress tensor, in Pascals (Pa). Indicates working conditions In position The strain tensor; This represents the elasticity matrix of the steel pipe material, whose components are derived from the material's elastic modulus. (Unit: Pa) and Poisson's ratio (No unit) Jointly decided.

[0028] The final output is for each working condition. Corresponding stress field distribution This serves as the input for subsequent steps to extract the extreme stress and coordinates of specific cross sections.

[0029] In pumped storage power stations, the stress distribution on the pressure steel pipe is affected by multiple factors, including upstream and downstream water levels, guide vane opening, and unit rotation speed. Relying solely on empirical point placement cannot accurately grasp the global stress characteristics. By establishing a complete three-dimensional simulation model and performing fluid-structure interaction analysis, all operating conditions can be covered, and the dynamic evolution of the stress field can be obtained, laying the foundation for subsequent database construction and sensor deployment.

[0030] Fluid-structure interaction (FSI) analysis can directly transfer the effect of fluid pressure on the inner wall of a steel pipe to the structural domain, avoiding the limitations of purely fluid or purely structural calculations. Especially at locations such as diameter changes and bifurcation points, where flow turbulence is significant and local stress peaks are difficult to identify empirically, this modeling and analysis approach ensures comprehensive, accurate, and repeatable data sources.

[0031] Traditional methods often rely on finite-condition tests or localized empirical calculations, which cannot obtain accurate stress fields under complex conditions such as start-up, shutdown, and partial load. This method, through full-condition simulation and fluid-structure interaction, avoids information loss, improves the completeness and reliability of stress prediction, and provides objective quantitative data support for subsequent steps.

[0032] S2: Extract the extreme stress and spatial coordinates of the special section from the stress field, and simultaneously record the principal stress direction to form a special location database containing a set of stress characteristic parameters, which is used to guide the monitoring layout.

[0033] In step S1, the stress field distribution under each operating condition is obtained. Next, the set of special cross-sections of the water conveyance system is determined: in, This represents a set of special cross-sections of a water conveyance system; This represents the first section (one of the variable diameter sections) in the set of special sections. This indicates the second section (one of the variable diameter sections) in the set of special sections. This represents the third section (the section in front of the bifurcation pipe) in the set of special sections. This represents the 4th section in the set of special sections (one of the sections after the bifurcation). This represents the 5th section in the set of special sections (one of the sections after the bifurcation). This represents the 6th section in the set of special sections (the location of the maximum stress along the line).

[0034] For sets Each section In the stress field We perform circumferential and axial traversal calculations to determine the cross-section under the working conditions. Extreme stress at the following conditions: in, Indicates working condition With cross section Extreme equivalent stress on; Indicates the first A quaternion of operating conditions; Represents the first in the set of special sections One cross section; Indicates the location of the cross section ; Indicates working condition Time position In-plane equivalent stress; Indicates working condition Time position Circumferential normal stress; Indicates working condition Time position Axial normal stress; Indicates working condition Time position Circumferential-axial shear stress.

[0035] And extract the corresponding spatial coordinates: in, Indicates working condition With cross section The spatial coordinates that maximize the equivalent stress.

[0036] While determining the extreme stress point, the formula for solving the principal stress direction is used: in, Indicates working condition With cross section The principal stress direction angle at the extreme point; atan2 This represents the bivariate arctangent function.

[0037] Simultaneously record the principal stress directions at this point. For shear stress components, For circumferential normal stress, It is the axial normal stress.

[0038] Based on working conditions With cross section For indexing, create database entries at specific locations: Meanwhile, in order to reflect the variation of extreme points under different working conditions, spatial coordinates were adjusted. Serialization and storage yield the trajectory of the extreme points: in, Indicates working conditions With cross section For database entries in specific index locations; Indicated in the cross section The set of extreme point trajectories that vary with operating conditions; This represents the set of operating conditions.

[0039] This is used to characterize the migration of the extreme points of the cross section under different operating conditions. The final output is a database of specific locations containing three core types of information for each cross section: extreme stress, spatial coordinates, and principal stress directions, as well as the trajectory of the extreme points evolving with different operating conditions. This provides a deterministic basis for the subsequent placement and orientation of resistance strain gauges.

[0040] Safety hazards in pressure steel pipes are mainly concentrated in special locations such as diameter transition sections, bifurcation points, and points of maximum stress. Conventional experience alone is insufficient to grasp stress changes at these locations under all operating conditions. By extracting the extreme stresses and principal stress directions of special cross-sections and establishing a database, a knowledge system that updates with changing operating conditions can be formed to guide the rational placement of sensors.

[0041] The database entries not only contain stress values ​​and coordinates, but also record the principal stress directions and the trajectory of extreme points as the operating conditions change, thus reflecting the spatial evolution of stress distribution. This design is because, during long-term operation, the maximum stress point is not fixed but shifts with the operating conditions, and trajectory serialization is necessary to avoid monitoring blind spots.

[0042] Traditional techniques typically determine only a small number of sensor placement points during the static design phase, lacking a dynamic update mechanism in later stages. This method, however, establishes a database to achieve structured management of stress extreme value information, freeing sensor placement from experience and basing it on quantitative data, thereby improving the scientific rigor and adaptability of sensor deployment.

[0043] S3: Based on the database results, three sets of resistance strain sensors are arranged at each special cross section. The three sets of sensors form a strain rosette and are oriented in accordance with the principal stress direction.

[0044] For the cross section First, based on the dominant direction angle calculated in S2 Combining the principle of equal arc length intervals, the circumferential angular domain of the cross section is... The segments are divided into three equal parts. The three sets of central angles are as follows: in, Indicates a special cross section The center angle of the first set of resistance strain gauges; Indicates a special cross section The center angle of the second set of resistance strain sensors; Indicates a special cross section The center angle of the third group of resistance strain gauges; It represents the dominant orientation angle given by the special location database, that is, the circumferential angle used as the orientation reference, which is obtained by summarizing the working conditions with weights. Represents a set of special locations The first in A special cross section; It represents pi (π).

[0045] Using the section parameterization function established in S2 Map the three sets of central angles to the coordinates of the cross-section surface: in, Indicates the first Spatial coordinates of the group of resistance strain gauges; Indicates the circumferential angle Mapping to Section Parameterized functions for outer surface coordinates; Indicates the first The central angle of the group; Indicates the group number of the sensor group, and the set of values. ; express The angle independent variable is the circumferential angle of the cross section.

[0046] In each sensor group center coordinates Three resistance strain gauges are attached to the location. The orientation angles of the three gauges are based on the dominant direction angles in a specific location database. Sure: in, Indicates the first The orientation angle of the first resistance strain sensor in the strain gauge rosette coincides with the dominant direction; Indicates the first The direction-finding angle of the second resistance strain sensor in the strain gauge group is 60° positively deflected relative to the dominant direction; Indicates the first The direction-finding angle of the third resistance strain sensor in the strain gauge group is negatively deflected by 60° relative to the dominant direction.

[0047] This arrangement ensures that the first strain gauge is precisely aligned along the principal stress direction, while the second and third gauges are deflected relative to the principal stress direction. With -60°, thus forming a complete strain flower.

[0048] To ensure that the three sets of resistance strain sensors cover the high-frequency region of extreme stress, based on the set of extreme point trajectories recorded in S2: in, Representing the cross section The set of extreme point trajectories is used to reflect the spatial migration trajectory of extreme points under different working conditions; Indicates working conditions In cross section The spatial coordinates of the extreme stress; Indicates the first A quaternion for each operating condition; This represents the set of all possible operating conditions.

[0049] The sector with the highest frequency of statistical extreme points is identified by the center angle of at least one set of sensors. Adjust the arrangement to the range of this sector. This ensures that the three arrangements not only meet the principle of equal arc length intervals, but also cover the main distribution area of ​​the extreme points.

[0050] In coordinates Complete surface treatment (sanding, rust removal, degreasing), according to angle Three resistance strain sensors are attached and cured. After attachment, the spatial coordinates and orientation angle information of each group are synchronously written into a special location database to form an updated layout information table.

[0051] After completion, each special section Three sets of spatial coordinates and strain rosette orientation angles of the resistance strain sensors were obtained: This result serves as the input for subsequent steps, including real-time data acquisition and principal stress recalculation.

[0052] Simply placing a single-point sensor on a cross-section cannot simultaneously capture the direction and changes of the principal stress. By arranging three sets of sensors evenly in the circumference, and making each set of three sensors form a strain rose structure, it is possible to achieve omnidirectional capture of the stress state locally, and ensure that at least one set is highly consistent with the direction of the principal stress.

[0053] Strain gauges are a standard method for verifying the direction and amplitude of principal stresses. Evenly distributing three sets of strain gauges ensures that the overall stress state of the cross-section is covered. By combining the principal stress directions and extreme point trajectories output from the database, the sensors can be oriented and preferentially sector-attached, ensuring that the sensor placement remains consistent with the actual principal stress axis during long-term operation.

[0054] Traditional strain gauge placement methods often involve mounting single-point sensors at empirical locations such as welds or elbows, which can easily lead to orientation mismatches and blind spots. This method, through the directional placement of three sets of strain gauges guided by a database, not only improves the consistency between monitoring results and actual stress but also enhances failure resistance and redundancy, significantly outperforming empirical placement methods.

[0055] S4: Compare real-time sensor data with database entries. When the monitored value exceeds the discrimination threshold, calibration and early warning are triggered. Abnormal events are used as weighted inputs for damage accumulation, and maintenance priorities are output, thereby realizing adaptive directional monitoring, discrimination and dynamic maintenance of pressure steel pipes under all working conditions.

[0056] After the three sets of resistance strain sensors in S3 are deployed, the real-time monitoring and judgment phase begins. The three sets of sensors at each specific cross-section continuously collect strain data, which is then converted into principal stress values ​​using elasticity relationships.

[0057] First, the system compares the principal stresses obtained from real-time monitoring with the stress values ​​of the corresponding sections in the database of special locations. The comparison method is normalized difference calculation. When the monitoring result exceeds the range of ±20% of the maximum or minimum value in the database, the system triggers the anomaly detection logic.

[0058] Anomaly detection is divided into two categories: Yellow light event: When the monitoring result slightly exceeds the limit, that is, exceeds the database range but is still below the material yield strength threshold, the system marks it as a yellow light event, indicating that it enters a key monitoring state.

[0059] Red light event: When the monitoring results are seriously out of range, that is, when they are both outside the database range and close to or exceed the material yield strength threshold, the system marks it as a red light event, indicating that it has entered a high-risk state and triggers an immediate warning.

[0060] Subsequently, the system incorporates the identified yellow and red light events as weighting factors into the fatigue damage accumulation analysis. First, the Miner linear damage model is used to calculate the cumulative damage, taking into account the number of cycles within the stress amplitude range and the allowable number of cycles for the material at that stress amplitude.

[0061] Based on this, a weighted correction for yellow and red light events is introduced to obtain a weighted damage index. Thus, when a yellow light event occurs, the cumulative damage value increases moderately; when a red light event occurs, the cumulative damage value increases significantly, thereby highlighting high-risk sections.

[0062] Finally, the system sorts the weighted damage indices of all special sections to generate a dynamic maintenance priority list. This list guides maintenance personnel to prioritize the maintenance of sections with high damage indices, achieving a closed-loop system for adaptive directional monitoring, anomaly detection, and dynamic maintenance of pressure steel pipes under all operating conditions.

[0063] Simply relying on statistical analysis of stress time history cannot identify risks from sudden operating conditions in a timely manner. By comparing sensor data with the database range in real time, out-of-limit situations can be detected immediately. By incorporating abnormal events into damage accumulation analysis and weighting corrections, real-time monitoring and long-term fatigue assessment can be linked, ultimately outputting dynamic maintenance priorities.

[0064] Setting a ±20% threshold as the discrimination boundary in database comparison can balance error tolerance and sensitivity, avoiding excessive alarms or missed alarms. Categorizing abnormal events into yellow and red lights helps to adopt differentiated response strategies under different risk levels. Introducing weighted corrections is to reflect the accelerating effect of abnormal events on the damage process, making the model more consistent with the actual operating environment.

[0065] Traditional methods often calculate cumulative damage after the fact based on rainflow counts, failing to incorporate real-time anomaly monitoring for dynamic adjustments. This method, through a closed loop of "monitoring-discrimination-weighting-ranking," couples real-time events with a fatigue life model, significantly improving the scientific rigor and foresight of maintenance strategies, thereby enhancing operational safety and maintenance efficiency.

[0066] This embodiment also provides a system for monitoring the stress of pressure steel pipes in pumped storage power stations and arranging sensors, including: The simulation modeling module is used to establish a three-dimensional simulation model of the pressure steel pipe and the unit flow channel based on the operating parameters collected by the operation monitoring system, and to obtain the stress field under various operating conditions through fluid-structure interaction analysis.

[0067] The special location database module is used to extract the extreme stress and spatial coordinates of special sections in the stress field, and simultaneously record the principal stress directions to form a database entry containing a set of stress characteristic parameters, and store the trajectory of extreme points.

[0068] The sensor arrangement module is used to uniformly arrange three sets of resistance strain sensors in the circumferential direction of each special cross section according to the results of the special location database, and to make each set form a strain rose structure and be oriented according to the principal stress direction.

[0069] The data comparison and discrimination module is used to compare the real-time monitoring data of the sensor with the special location database entries, and to trigger sensor calibration or warning when the monitoring result exceeds the stress range of the database.

[0070] The damage accumulation and weighting module is used to classify abnormal events into mild and severe exceedances, forming yellow light events and red light events respectively, and to use these events as weighting factors to correct the fatigue damage accumulation results.

[0071] The maintenance priority module is used to sort special sections based on the corrected damage results and output a maintenance priority list to guide the dynamic maintenance of pressure steel pipes.

[0072] This embodiment also provides a computer device applicable to the method of stress monitoring and sensor arrangement for pressure steel pipes in pumped storage power stations, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize the method of stress monitoring and sensor arrangement for pressure steel pipes in pumped storage power stations as proposed in the above embodiment.

[0073] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0074] This embodiment also provides a storage medium storing a computer program. When executed by a processor, the program implements the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for stress monitoring and sensor arrangement in the pressure steel pipe of a pumped storage power station, characterized in that, include: Based on the operating condition parameters collected by the pumped storage power station operation monitoring system, a three-dimensional simulation model of the pressure steel pipe and the unit flow channel is established. The pressure distribution of the flow channel is calculated based on the set of operating conditions, and the stress field under each operating condition is obtained through fluid-structure interaction analysis. The operating condition parameters include upstream water level, downstream water level, guide vane opening degree, and unit speed. The calculation of the pressure distribution in the flow channel includes, in the three-dimensional simulation model, performing fluid numerical solution of the water conveyance channel based on the Reynolds time-averaged N-S equation, and obtaining the pressure distribution results of the inner wall of the pressure steel pipe under different operating conditions. The process of obtaining the stress field under each working condition includes applying the pressure distribution result as a boundary load directly to the pressure steel pipe structure of the three-dimensional simulation model, and solving it using the fluid-structure interaction finite element analysis method to obtain the stress field of the pressure steel pipe under each operating condition. The extreme stress and spatial coordinates of special cross sections are extracted from the stress field, and the principal stress directions are recorded simultaneously to form a special location database containing a set of stress characteristic parameters, which is used to guide the monitoring layout. The formation of the special location database includes determining the set of special cross sections in the water conveyance system under the stress field of each operating condition; The special cross section is analyzed to extract the extreme stress and its spatial coordinates on the outer surface of the pressure steel pipe, and the principal stress direction is recorded simultaneously; special location database entries are established using the working conditions and cross section as indexes; and the changes of the spatial coordinates with the operating conditions are serialized and stored to obtain the extreme point trajectory, which is used to guide the subsequent placement and orientation of sensors; The set of special sections includes variable diameter sections, sections before and after bifurcated pipes, and the location of maximum stress along the line; the entries include the extreme stress, spatial coordinates, and principal stress direction information; Based on the database results, three sets of resistance strain sensors are arranged at each special cross section, and the three sets of sensors form a strain rose and are oriented in accordance with the principal stress direction. By comparing real-time sensor data with database entries, calibration and early warning are triggered when the monitored value exceeds the discrimination threshold. Abnormal events are used as weighted inputs for damage accumulation, and maintenance priorities are output, thereby realizing adaptive directional monitoring, discrimination, and dynamic maintenance of pressure steel pipes under all working conditions.

2. The method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in claim 1, characterized in that: The arrangement of the three sets of resistance strain sensors includes setting three sets of resistance strain sensors at equal arc length intervals in the circumferential direction of each special cross section, with each set of resistance strain sensors attached to the surface corresponding to the extreme stress coordinates recorded in the special position database.

3. The method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in claim 2, characterized in that: The three sets of sensors forming a strain rosette include three resistance strain sensors arranged at equal angular intervals in each set. The first strain sensor is oriented along the principal stress direction, while the other two strain sensors are oriented at equal angles relative to the principal stress direction in the circumferential direction. The three sets of resistance strain sensors are oriented and corrected based on the direction angle determined by the principal stress direction under different operating conditions. The priority application sector is determined based on the distribution results of the extreme point trajectory to ensure that the sensor arrangement covers the high-frequency occurrence area of ​​the principal stress.

4. The method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in claim 3, characterized in that: The step of comparing real-time sensor data with entries in a special location database includes comparing the monitored principal stress with the stress range recorded in the special location database, and triggering sensor calibration or an early warning when the monitoring result exceeds the stress range.

5. The method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in claim 4, characterized in that: The step of using abnormal events as weighted input for damage accumulation includes classifying triggered abnormal events according to their severity, where events triggered by minor over-limits are designated as yellow light events, indicating entry into a key monitoring state, and events triggered by severe over-limits are designated as red light events, indicating entry into a high-risk state, and the yellow light events and red light events are used to weight and correct the accumulated damage results. The output maintenance priority includes sorting each special section according to the corrected damage results to form a maintenance priority list.

6. A system for monitoring stress in the pressure steel pipes of a pumped storage power station and arranging sensors, based on the method for monitoring stress in the pressure steel pipes of a pumped storage power station as described in any one of claims 1 to 5, characterized in that: The simulation modeling module is used to establish a three-dimensional simulation model of the pressure steel pipe and the unit flow channel based on the operating parameters collected by the operation monitoring system, and to obtain the stress field under various operating conditions through fluid-structure interaction analysis. The operating parameters include upstream water level, downstream water level, guide vane opening, and unit speed; The calculation of the pressure distribution in the flow channel includes, in the three-dimensional simulation model, performing fluid numerical solution of the water conveyance channel based on the Reynolds time-averaged N-S equation, and obtaining the pressure distribution results of the inner wall of the pressure steel pipe under different operating conditions. The process of obtaining the stress field under each working condition includes applying the pressure distribution result as a boundary load directly to the pressure steel pipe structure of the three-dimensional simulation model, and solving it using the fluid-structure interaction finite element analysis method to obtain the stress field of the pressure steel pipe under each operating condition. The special location database module is used to extract the extreme stress and spatial coordinates of special sections in the stress field, and simultaneously record the principal stress direction to form a database entry containing a set of stress characteristic parameters and store the trajectory of extreme points; forming the special location database includes determining the set of special sections in the water conveyance system in the stress field of each operating condition. The special cross section is analyzed to extract the extreme stress and its spatial coordinates on the outer surface of the pressure steel pipe, and the principal stress direction is recorded simultaneously; special location database entries are established using the working conditions and cross section as indexes; and the changes of the spatial coordinates with the operating conditions are serialized and stored to obtain the extreme point trajectory, which is used to guide the subsequent placement and orientation of sensors; The set of special sections includes variable diameter sections, sections before and after bifurcated pipes, and the location of maximum stress along the line; the entries include the extreme stress, spatial coordinates, and principal stress direction information; The sensor arrangement module is used to uniformly arrange three sets of resistance strain sensors in the circumferential direction of each special cross section according to the results of the special location database, and to make each set form a strain rose structure and be oriented according to the principal stress direction. The data comparison and discrimination module is used to compare the real-time monitoring data of the sensor with the special location database entries, and to trigger sensor calibration or warning when the monitoring result exceeds the stress range of the database. The damage accumulation and weighting module is used to classify abnormal events into mild and severe exceedances, forming yellow light events and red light events respectively, and using the events as weighting factors to correct the fatigue damage accumulation results; The maintenance priority module is used to sort special sections based on the corrected damage results and output a maintenance priority list to guide the dynamic maintenance of pressure steel pipes.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the method for stress monitoring and sensor arrangement of pressure steel pipes in pumped storage power stations as described in any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the method for monitoring the stress of the pressure steel pipe and arranging sensors in a pumped storage power station as described in any one of claims 1 to 5.

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