A safety risk prediction method and system for a pipeline system of a pumping station

Abstract

The present application relates to the technical field of safety evaluation of pipeline system of pumping station in water conservancy and agricultural irrigation, and specifically discloses a safety risk prediction method and system for pipeline system of pumping station; by acquiring engineering parameters and operation condition setting parameters of a target system, steady-state hydraulic simulation is carried out based on this, and initial steady-state operation parameters of the system under the set condition are obtained; a disturbance event is set and water hammer transient hydraulic simulation is carried out, and transient hydraulic parameter sequences of key nodes are calculated; combined with steady-state and transient parameters, safety risk events that may occur in the system, such as overpressure damage, cavitation, equipment overload, medium backflow and pipeline vibration, are analyzed and predicted; and finally, a risk analysis report containing prediction results and corresponding conditions is generated. The present application realizes active and quantitative prediction of safety risks of the pipeline system of the pumping station under various conditions and disturbances, and provides a scientific basis for optimizing operation, improving engineering design and taking protective measures.

Description

A method and system for predicting safety risks in pumping station pipeline systems Technical Field

[0001] This invention relates to the field of safety assessment technology for pumping station pipeline systems in water conservancy projects and agricultural irrigation, and specifically discloses a safety risk prediction method and system for pumping station pipeline systems. Background Technology

[0002] The pipeline system of pumping stations is a key facility in water conservancy projects and agricultural irrigation, and its operational safety is directly related to water supply security and project benefits. During operation, especially when pumps start and stop, valves are operated, and other operating conditions change, the system is highly susceptible to transient processes such as water hammer caused by rapid changes in flow and pressure. This can lead to violent fluctuations in pipeline pressure, potentially inducing a series of safety risks such as pipeline rupture, equipment damage, and cavitation vibration.

[0003] Currently, safety management for such systems largely relies on theoretical calculations during the design phase, the development of operating procedures, and post-event experience summaries. The design phase typically involves simplified steady-state hydraulic calculations and potential water hammer estimations, but these are insufficient to fully cover the complex combinations of operating conditions and disturbances encountered in actual operation. The operation phase primarily relies on periodic inspections, instrument monitoring, and historical fault analysis. While this approach has some effectiveness, it is a reactive measure, lacking the foresight and quantitative prediction capabilities for potential risks, especially for accurate assessment of complex transient processes involving multiple coupled factors.

[0004] Therefore, existing technologies lack a method that can systematically integrate engineering parameters, operating conditions, and dynamic hydraulic simulations to proactively and quantitatively predict potential safety risks to pumping station pipeline systems under various settings and disturbances. This results in an information gap between engineering design and operation and maintenance, making it impossible to provide sufficient and accurate decision-making basis in advance for optimizing operating strategies, improving engineering design, or adding protective facilities, thus hindering further improvements in system safety and reliability. Summary of the Invention

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] According to a first aspect of the present invention, the present invention claims protection for a safety risk prediction method for a pumping station pipeline system, the method comprising the following steps:

[0007] S1. Obtain the engineering parameters and operating condition setting parameters of the target pumping station pipeline system;

[0008] S2. Based on the engineering parameters and operating condition setting parameters, perform steady-state hydraulic simulation on the pumping station pipeline system to calculate the initial steady-state operating parameters of the system under the set operating conditions.

[0009] S3. Based on the engineering parameters, operating condition setting parameters and the initial steady-state operating parameters, a disturbance event is set, and a water hammer transient hydraulic simulation is performed on the pumping station pipeline system to calculate the transient hydraulic parameter sequence of key nodes of the pipeline system under the disturbance event.

[0010] S4. Based on the initial steady-state operating parameters and the transient hydraulic parameter sequence, analyze and predict the safety risk events that may occur in the pumping station pipeline system under the set operating conditions and disturbance events;

[0011] S5. Generate and output a risk analysis report containing the predicted safety risk events and their corresponding operating conditions.

[0012] Further, step S2 includes:

[0013] S21. Based on the engineering parameters, determine the topology, component composition, and geometric parameters of the pumping station pipeline system;

[0014] S22. Based on the operating conditions, set parameters to determine the initial operating flow rate and head of the pump in the system;

[0015] S23. Based on the initial operating flow rate and head of the pump, and combined with the topology and resistance characteristics of the pipeline system, calculate the pump shaft power, motor current, pressure and flow rate before and after each valve in the pipeline, pipeline friction loss, local loss, total hydraulic loss and outlet pressure when the system is running in steady state.

[0016] S24. Based on the calculated pipeline pressure distribution data, generate and store the pressure distribution curve along the pipeline length from the pump outlet to the end of the pipeline, as part of the initial steady-state operating parameters.

[0017] Furthermore, step S1 includes:

[0018] S11. Obtain the pump's performance parameters, including rated flow rate, rated head, rated speed, high-efficiency range, shaft power characteristic curve or data, and pump's moment of inertia.

[0019] S12. Obtain valve parameters, including valve type, nominal diameter, local resistance coefficient in the fully open state, and characteristic data of how the resistance coefficient of a control valve or check valve changes with the opening degree or flow direction.

[0020] S13. Obtain the parameters of the inlet and outlet water pipelines, including the material, inner diameter, wall thickness, length, installation height, friction coefficient of each pipe section, and the local resistance coefficient of elbows, tees, and reducers in the pipeline.

[0021] S14. Obtain inlet and outlet boundary condition parameters, including the design water level and amplitude of the inlet pool, the design water level and pressure of the outlet pool or outlet point, and whether the boundary is a constant water level or has a time-varying pattern.

[0022] S15. Obtain medium parameters and environmental parameters, wherein the medium parameters include the density and temperature of the transported liquid, and the environmental parameters include the local gravitational acceleration;

[0023] S16. Obtain the operating condition setting parameters, which include the target operating flow rate or head setting value of the pump in the steady-state simulation, the initial opening setting value of the valve, and the type and parameters of the planned disturbance event in the water hammer simulation.

[0024] Further, step S3 includes:

[0025] S31. Based on the engineering parameters and the initial steady-state operating parameters, set the calculation conditions for water hammer simulation, including the total calculation time, the calculation time step, and the wave velocity of the pressure wave in the pipeline.

[0026] S32. Define disturbance events as the causes of water hammer simulation. The disturbance events include pump start-up, normal pump shutdown, pump accident shutdown, linear valve closure operation, two-stage valve closure operation, or accidental fast valve closure.

[0027] S33. Based on the defined disturbance event, determine the sequence of control parameters that change over time in the disturbance event. For the valve closing event, determine the valve closing pattern and the corresponding resistance coefficient change sequence. For the pump start-stop event, determine the pump speed change pattern and the corresponding head-flow characteristic change sequence.

[0028] S34. Based on the method of characteristics, establish a mathematical model for calculating water hammer in the pumping station pipeline system. The model includes the basic characteristic equations describing the transient flow in the pipeline and the boundary condition equations describing the pumps, valves, and inlet / outlet water tanks.

[0029] S35. Using the initial steady-state operating parameters as the initial conditions for transient simulation, and the time-varying control parameter sequence as the input of boundary conditions, the water hammer calculation mathematical model is used to perform time-step recursive calculation to obtain the transient hydraulic parameter sequence of pressure and flow rate at key nodes of the pipeline system during the total calculation time.

[0030] Furthermore, in step S33, when the disturbance event is a two-stage closing operation of the valve, determining the valve closing pattern specifically includes:

[0031] S33a. Obtain the setting parameters for the two-stage closing, including the total time of the fast closing phase, the closing angle of the fast closing phase, the total time of the slow closing phase, and the closing angle of the slow closing phase.

[0032] S33b. During the simulation time-step recursive calculation, determine the relationship between the current cumulative time and the two-stage shutdown setting parameter:

[0033] If the current cumulative time is less than or equal to the total time of the fast closing phase, the closing angle of the valve at the current time step is linearly calculated based on the total time and closing angle of the fast closing phase. If the current cumulative time is greater than the total time of the fast closing phase and less than or equal to the sum of the total time of the fast closing and slow closing phases, the closing angle of the valve at the current time step is linearly calculated based on the total time and closing angle of the slow closing phase. If the current cumulative time is greater than the sum of the total time of the fast closing and slow closing phases, the valve is determined to be in a fully closed state.

[0034] S33c. Based on the calculated valve closing angle at the current time step, query the characteristic data of the valve resistance coefficient changing with the opening degree, determine the local resistance coefficient of the valve at the current time step, and use it to update the valve boundary condition equation in the water hammer calculation mathematical model.

[0035] Furthermore, in step S33, when the disturbance event is an accidental shutdown of the pump, determining the pump's speed change pattern and the corresponding head-flow characteristic change sequence specifically includes:

[0036] S33d, The steady-state operating speed of the pump at the moment of emergency shutdown is taken as the initial speed;

[0037] S33e. At each simulation time step, based on the rotational inertia of the pump unit rotor, the pump torque and motor torque corresponding to the pump's operating condition point in the previous time period, calculate the change in pump speed at the current time step to obtain the current pump speed.

[0038] S33f. Based on the similarity principle of pumps, according to the ratio of the current speed to the rated speed, the rated head-flow characteristic curve of the pump is proportionally transformed to obtain the transient head-flow characteristic relationship of the pump at the current time step.

[0039] S33g, Solve the transient head-flow characteristic relationship of the pump under the current time step and the compatibility equation of the pipeline at the pump node to obtain the flow rate through the pump and the pressure difference between the pump inlet and outlet during the current time period, and then calculate the transient pressure value of the pump outlet node.

[0040] Further, step S4 includes:

[0041] S41. Extract steady-state risk indicators from the initial steady-state operating parameters. The steady-state risk indicators include the steady-state operating shaft power of the pump, the steady-state current of the motor, and the maximum and minimum values ​​of the steady-state pressure of the pipeline.

[0042] S42. Extract transient risk indicators from the transient hydraulic parameter sequence. The transient risk indicators include the maximum pressure, minimum pressure, maximum pressure rise rate, maximum pressure fall rate, and the magnitude and duration of flow reversal at key pipeline nodes throughout the transient process.

[0043] S43. Compare the extracted steady-state risk indicators with the preset steady-state safety threshold, and compare the extracted transient risk indicators with the preset transient safety threshold.

[0044] Further, step S4 analyzes and predicts security risk events, including comprehensively predicting at least one of the following specific security risk events based on the comparison results:

[0045] S44a. If the steady-state operating shaft power of the pump continuously exceeds the rated power of its matching motor, or the steady-state current of the motor exceeds its rated current, then it is predicted that there is a risk of equipment overload operation.

[0046] S44b. If the minimum pressure at a node in the pipeline during a steady-state or transient process is lower than the vaporization pressure of the transported medium at the current temperature, then it is predicted that there is a risk of cavitation at that node.

[0047] S44c. If the maximum pressure at a node in the pipeline during a transient process exceeds the rated pressure bearing capacity of the pipeline component or pipe material, it is predicted that there is a risk of overpressure damage due to water hammer at that node.

[0048] S44d. If the transient simulation results show that the flow reverses in the pipeline after the pump outlet check valve and the duration exceeds the set threshold, it is predicted that there is a risk of medium backflow impacting the pump reversal.

[0049] S44e. If the pressure fluctuation at critical nodes of the pipeline is too large or the rate of pressure change is too fast, it is predicted that there is a risk of causing severe pipeline vibration or support instability.

[0050] S44f: Based on the predicted risk event type, location, and severity, the risk analysis report generated in step S5 provides corresponding risk level prompts and descriptions of potential consequences.

[0051] Further, step S5 includes:

[0052] S51. Basic information of the pumping station pipeline system and description of the set operating conditions;

[0053] S52. A summary of the main results of the steady-state hydraulic simulation, including the pump operating point, key node pressure, system efficiency, and hydraulic loss distribution;

[0054] S53. A summary of the main results of the water hammer transient hydraulic simulation, including a description of the simulated disturbance event, the maximum and minimum transient pressure values ​​of key nodes and their occurrence time, and a pressure envelope diagram;

[0055] S54, a list of all security risk events predicted in step S4, with each item specifying the risk type, judgment basis, risk location, and risk level;

[0056] S55. Suggestions for operational or design improvements in response to the predicted security risk events.

[0057] Furthermore, the operational or design improvement suggestions proposed in step S55 include at least one of the following:

[0058] S55a. In response to the predicted risk of severe water hammer overpressure caused by rapid valve closure, it is recommended to adjust the valve closure pattern, extend the closure time, or adopt a two-stage closure strategy, and re-simulate and verify the optimization effect based on this method.

[0059] S55b. In response to the predicted risk of low pressure or backflow caused by pump accident shutdown, it is recommended to add a slow-closing check valve or hydraulic check valve at the pump outlet, and to re-predict the safety risks of the system after the addition of the equipment based on this method.

[0060] S55c. In response to the predicted risks of general pressure fluctuations and vibrations, it is recommended to add air valves, pressure regulating towers, or water hammer eliminators at specific locations in the pipeline, and to re-simulate the modified system based on this method to assess the degree of risk mitigation.

[0061] According to a second aspect of the present invention, the present invention claims protection for a safety risk prediction system for a pumping station pipeline system, comprising:

[0062] One or more processors;

[0063] A memory storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the aforementioned safety risk prediction method for a pumping station pipeline system.

[0064] This invention relates to the field of safety assessment technology for pumping station pipeline systems in water conservancy projects and agricultural irrigation. Specifically, it discloses a method and system for predicting safety risks in pumping station pipeline systems. By acquiring the engineering parameters and operating condition setting parameters of the target system, steady-state hydraulic simulation is performed to obtain the initial steady-state operating parameters of the system under the set operating conditions. Disturbance events are set, and transient hydraulic simulation of water hammer is conducted to calculate the transient hydraulic parameter sequence of key nodes. Combining steady-state and transient parameter analysis, potential safety risk events of the system are predicted, such as overpressure failure, cavitation, equipment overload, medium backflow, and pipeline vibration. Finally, a risk analysis report containing the prediction results and corresponding operating conditions is generated. This invention achieves proactive and quantitative prediction of safety risks in pumping station pipeline systems under various operating conditions and disturbances, providing a scientific basis for optimizing operation, improving engineering design, and taking protective measures. Attached Figure Description

[0065] Figure 1 is a flowchart of a safety risk prediction method for a pumping station pipeline system claimed in an embodiment of the present invention;

[0066] Figure 2 is a second flowchart of a safety risk prediction method for a pumping station pipeline system claimed in an embodiment of the present invention.

[0067] Figure 3 is a third flowchart of a safety risk prediction method for a pumping station pipeline system claimed in an embodiment of the present invention;

[0068] Figure 4 is a fourth flowchart of a safety risk prediction method for a pumping station pipeline system claimed in an embodiment of the present invention. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0070] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications in the embodiments of this application, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationships and movements between components in a specific orientation as shown in the accompanying drawings. If the specific orientation changes, the directional indications will change accordingly. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0071] References to embodiments herein mean that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0072] According to a first embodiment of the present invention, referring to FIG1, the present invention claims protection for a safety risk prediction method for a pumping station pipeline system, the method comprising the following steps:

[0073] S1. Obtain the engineering parameters and operating condition setting parameters of the target pumping station pipeline system;

[0074] S2. Based on the engineering parameters and operating condition setting parameters, perform steady-state hydraulic simulation on the pumping station pipeline system to calculate the initial steady-state operating parameters of the system under the set operating conditions.

[0075] S3. Based on the engineering parameters, operating condition setting parameters and the initial steady-state operating parameters, a disturbance event is set, and a water hammer transient hydraulic simulation is performed on the pumping station pipeline system to calculate the transient hydraulic parameter sequence of key nodes of the pipeline system under the disturbance event.

[0076] S4. Based on the initial steady-state operating parameters and the transient hydraulic parameter sequence, analyze and predict the safety risk events that may occur in the pumping station pipeline system under the set operating conditions and disturbance events;

[0077] S5. Generate and output a risk analysis report containing the predicted safety risk events and their corresponding operating conditions.

[0078] In this embodiment, a complete description of the target pumping station pipeline system is received and stored through a user interface or data interface. This information is specifically divided into two categories: the first category is engineering parameters describing the physical structure of the system, and the second category is operating condition setting parameters describing the working state or events the system will experience. These parameters together constitute the digital definition of the simulated object.

[0079] Based on the acquired parameters, the steady-state hydraulic simulation module is initiated. This module first constructs a virtual pipeline system network model in memory according to the topological relationships in the engineering parameters. Then, it uses the pump target operating point (e.g., specified flow rate or head) in the operating condition settings as the driving objective for the calculation. Through the hydraulic calculation engine, it solves for the state when the entire system network achieves force and flow balance. The calculation process iteratively coordinates the pump performance characteristic curves with the pipeline network resistance characteristic curves until a stable operating point is found. Finally, it calculates the operating parameters of all key equipment in the system, such as pumps and motors (shaft power, current), the pressure and flow values ​​of all key nodes (e.g., before and after valves, pipe connections, outlet), and various hydraulic losses of the pipeline system (friction, local, and total losses). The complete dataset output in this step characterizes the initial equilibrium state of the system before any transient disturbance, providing an accurate starting point for subsequent transient analysis.

[0080] Based on the established steady-state baseline, and using predefined disturbance events described in the operating condition settings, such as a power outage at pump 2 after 3 seconds and linear closure of the outlet main valve within 10 seconds, the transient hydraulic simulation module for water hammer is initiated. This module employs time-domain analysis methods such as the method of characteristics to discretize the pipeline system into multiple calculation nodes and pipe segments. At the start of the simulation, the steady-state parameters obtained in step S2 are assigned as initial conditions for all nodes. Subsequently, the simulation clock advances incrementally. Within each micro-hour time step, boundary conditions are first updated according to the logic of the disturbance event, such as updating valve openings and changing pump speeds. Then, based on fluid mechanics principles, the propagation, reflection, and superposition effects of pressure waves in the pipeline network are calculated, thereby determining the instantaneous pressure and flow rate of each calculation node at that moment. This process continues until the simulation clock reaches the preset total simulation duration, ultimately generating a complete sequence of data on the time-varying parameters such as pressure and flow rate at key nodes. This sequence fully records the dynamic response history of the system under specific disturbances.

[0081] From the output steady-state data, indicators directly related to equipment safety and system stability are selected, such as the pump's continuous operating shaft power, motor operating current, and the pipeline's highest steady-state pressure. Secondly, from the output transient data sequence, characteristic indicators that characterize transient hazards are extracted, such as the pressure peak value, pressure trough value, maximum rate of pressure change, and whether flow reversal occurs and its duration at various points in the pipeline throughout the simulation. Next, these extracted steady-state and transient indicators are compared one by one with a safety threshold library pre-stored in the system database. This safety threshold library contains standards such as equipment rated parameters, material pressure limits, and net positive suction head (NPSH) requirements. The comparison logic not only determines whether standards are exceeded but also analyzes the magnitude and duration of exceedances, as well as the combined effects of multiple related indicators, thereby comprehensively inferring the specific risk types that may be triggered, such as overpressure rupture, cavitation, equipment overload, and flow reversal.

[0082] Integrating the processes and results of all the aforementioned steps, a structured electronic document is automatically generated as a risk analysis report. The report not only includes the final prediction conclusions—that is, what risks exist—but also must fully present the basis and context of the analysis. The report must systematically describe at least the following: an overview of the pumping station system targeted by the simulation and a brief description of the simulated operating conditions; a summary of the main results of the steady-state simulation and a system energy efficiency assessment; a description of the disturbance scenarios in the transient simulation, key dynamic response curves such as pressure envelope diagrams, and extreme value statistics; a detailed list of risk predictions, specifying the type of each predicted risk, its location, the indicators and thresholds used for judgment, and the severity level assessment; and targeted improvement suggestions based on the prediction results for engineering design or operation. This report is delivered to the user via screen display, file saving, or network transmission.

[0083] Further, referring to Figure 2, step S2 includes:

[0084] S21. Based on the engineering parameters, determine the topology, component composition, and geometric parameters of the pumping station pipeline system;

[0085] S22. Based on the operating conditions, set parameters to determine the initial operating flow rate and head of the pump in the system;

[0086] S23. Based on the initial operating flow rate and head of the pump, and combined with the topology and resistance characteristics of the pipeline system, calculate the pump shaft power, motor current, pressure and flow rate before and after each valve in the pipeline, pipeline friction loss, local loss, total hydraulic loss and outlet pressure when the system is running in steady state.

[0087] S24. Based on the calculated pipeline pressure distribution data, generate and store the pressure distribution curve along the pipeline length from the pump outlet to the end of the pipeline, as part of the initial steady-state operating parameters.

[0088] In this embodiment, engineering parameters are analyzed to construct a virtual pipeline system diagram in the computing environment. This process includes: creating pipe segments with nodes such as pump outlet points, valve connection points, branch points, outlet points, and connection nodes based on pipe segment connection relationships; associating each pipe segment with its geometric parameters, length, diameter, and friction coefficient; installing virtual equipment components on the corresponding nodes, such as associating pump components with pump nodes and configuring performance curve data for them; and associating valve components with valve nodes and configuring opening-resistance characteristic data for them.

[0089] The core of reading the steady-state operation instructions from the operating condition settings is to determine the pump's initial operating point. This could be specifying a target flow rate, a target head, or requiring the pump to operate at its rated speed. This setting will serve as the target or constraint for subsequent hydraulic balance calculations.

[0090] The calculation engine starts from the initial operating point of the pump and assumes a flow rate through the pump. Based on this flow rate and the pump's performance curve, the head provided by the pump is obtained. Then, starting from the pump outlet, along the pipeline topology, the pressure drop is calculated segment by segment based on the pipeline's resistance characteristics using formulas for friction loss and local loss. This calculation is performed based on the current flow rate, pipe diameter, length, friction coefficient, and local resistance coefficient, until the system outlet boundary, such as the water surface in a pool, is reached. The calculated required pump head (the difference between the outlet boundary pressure and the inlet pressure), plus the total pipeline loss, is compared with the head the pump can provide at the current flow rate. If the two do not match, the assumed flow rate value is adjusted according to a preset algorithm, such as the Newton-Raphson iteration method, and the above calculation is repeated. This iterative process is repeated until the difference between the pump's provided head and the system's required head is less than a small convergence tolerance. At this point, the system reaches hydraulic balance, and a unique steady-state operating flow rate is obtained.

[0091] After obtaining the equilibrium flow rate, the system back-calculates all intermediate states. With this equilibrium flow rate fixed, the pump shaft power is recalculated based on flow rate, head, and efficiency; the motor current is estimated based on motor power and voltage; and the pressure value at each calculation node in the pipeline is calculated. Specifically, the pressure at each point along the pipeline from the pump outlet to the end of the pipeline is calculated, forming a set of distance-pressure data pairs. Simultaneously, the friction losses along all pipe sections, the local losses of all local components such as valves and elbows, are summarized, and the total hydraulic loss of the system is obtained by summing them. All these calculation results, including but not limited to the equilibrium flow rate, pump operating point parameters, node pressure distribution, and various loss values, are structured and stored in memory or a database, marked as the initial steady-state operating parameter set.

[0092] Based on the friction pressure data obtained from S24 calculation, a two-dimensional curve is created using the graphics generation module. The horizontal axis of this curve represents the cumulative length of the pipeline from the pump outlet, and the vertical axis represents the fluid pressure at the corresponding point. This curve is saved as image data or redrawable vector data, serving as an important component of the steady-state operating results to visually display the pressure gradient of the system under steady-state conditions.

[0093] Furthermore, step S1 includes:

[0094] S11. Obtain the pump's performance parameters, including rated flow rate, rated head, rated speed, high-efficiency range, shaft power characteristic curve or data, and pump's moment of inertia.

[0095] S12. Obtain valve parameters, including valve type, nominal diameter, local resistance coefficient in the fully open state, and characteristic data of how the resistance coefficient of a control valve or check valve changes with the opening degree or flow direction.

[0096] S13. Obtain the parameters of the inlet and outlet water pipelines, including the material, inner diameter, wall thickness, length, installation height, friction coefficient of each pipe section, and the local resistance coefficient of elbows, tees, and reducers in the pipeline.

[0097] S14. Obtain inlet and outlet boundary condition parameters, including the design water level and amplitude of the inlet pool, the design water level and pressure of the outlet pool or outlet point, and whether the boundary is a constant water level or has a time-varying pattern.

[0098] S15. Obtain medium parameters and environmental parameters, wherein the medium parameters include the density and temperature of the transported liquid, and the environmental parameters include the local gravitational acceleration;

[0099] S16. Obtain the operating condition setting parameters, which include the target operating flow rate or head setting value of the pump in the steady-state simulation, the initial opening setting value of the valve, and the type and parameters of the planned disturbance event in the water hammer simulation.

[0100] In this embodiment, a dedicated data input interface or structure for the pump equipment is provided. The required input data items include: pump model or design point parameters (rated flow rate, rated head, rated speed); curve data defining pump performance, typically provided in the form of data tables or fitting coefficients, covering flow-head and flow-efficiency curves; pump mechanical inertia parameters, i.e., the moment of inertia of the pump rotor and its coupling components, used for transient speed calculations; and pump installation geometry parameters, such as the inlet centerline elevation. For multi-pump parallel or series systems, the above parameterization must be performed individually for each pump.

[0101] It provides parameter input structures for various types of valves such as gate valves, butterfly valves, check valves, and slow-closing valves. For each type of valve, its nominal diameter and type must be entered. The core is to define its hydraulic characteristics: For adjustable valves such as gate valves and butterfly valves, one or more sets of data pairs need to be entered to describe the correspondence between the valve opening from 0% fully closed to 100% fully open and the local resistance coefficient when the valve is fully open at that opening. For check valves, it is necessary to define its opening pressure loss, full-opening resistance coefficient, and possible closing dynamic characteristics such as closing time and closing pattern. For water hammer protection valves such as two-stage closing hydraulic control check valves, it is also necessary to enter its fast closing and slow closing time and angle parameters.

[0102] This provides a structured input method for describing piping systems, requiring users to break down the entire pipeline into continuous segments. For each segment, the following must be entered: start and end node numbers or descriptions, pipe inner diameter, wall thickness, length, material (for determining the friction coefficient or directly entering the friction coefficient value), absolute roughness, and installation elevation variation. Simultaneously, for all local resistance elements present in this segment, such as standard elbows, reducers, and tees, their type, specifications, and corresponding local resistance coefficient values ​​must be specified individually, or the system can automatically associate the coefficients by selecting standard components. This step aims to build a complete pipeline network resistance database.

[0103] For inlet boundaries such as suction tanks, it is necessary to specify whether the water level is a fixed value or a function that changes over time, such as a water level-time curve. For outlet boundaries such as effluent tanks, pipe networks, and user terminals, it is also necessary to specify their pressure or water level conditions. If the outlet is a free outflow or opens to the atmosphere, the pressure can be set to atmospheric pressure; if the outlet connects to another pressurized system, the pressure value or pressure-flow relationship must be specified. The accurate definition of boundary conditions is a key prerequisite for the correctness of hydraulic calculations.

[0104] The most basic physical property of the transport medium is the fluid density, which directly affects the calculation of inertial force and pressure. If the medium is water, the slight effect of temperature on density and viscosity usually needs to be considered. It is permissible to input water temperature or directly input density value. At the same time, input the gravitational acceleration value of the calculation location. Standard value is usually used, but it can be used as an adjustable parameter under high accuracy requirements.

[0105] Users need to define two simulation scenarios: First, a steady-state simulation scenario, where users specify the desired steady-state condition for the system, such as specifying a pump to operate at a specific speed or requiring the system to reach a certain total flow rate. Second, a transient simulation scenario, where users need to program disturbance events: selecting one or more events from an event library, such as pump start / stop, valve action, and power failure; setting the occurrence time for each event, i.e., the second after the simulation starts; and setting detailed action parameters for each event. For example, for a valve closing event, selecting linear or two-stage closing behavior and setting corresponding time parameters; for a pump shutdown event, selecting the shutdown type, such as normal shutdown or power outage. These settings together constitute a complete, time-sequential simulation script.

[0106] Further, referring to Figure 3, step S3 includes:

[0107] S31. Based on the engineering parameters and the initial steady-state operating parameters, set the calculation conditions for water hammer simulation, including the total calculation time, the calculation time step, and the wave velocity of the pressure wave in the pipeline.

[0108] S32. Define disturbance events as the causes of water hammer simulation. The disturbance events include pump start-up, normal pump shutdown, pump accident shutdown, linear valve closure operation, two-stage valve closure operation, or accidental fast valve closure.

[0109] S33. Based on the defined disturbance event, determine the sequence of control parameters that change over time in the disturbance event. For the valve closing event, determine the valve closing pattern and the corresponding resistance coefficient change sequence. For the pump start-stop event, determine the pump speed change pattern and the corresponding head-flow characteristic change sequence.

[0110] S34. Based on the method of characteristics, establish a mathematical model for calculating water hammer in the pumping station pipeline system. The model includes the basic characteristic equations describing the transient flow in the pipeline and the boundary condition equations describing the pumps, valves, and inlet / outlet water tanks.

[0111] S35. Using the initial steady-state operating parameters as the initial conditions for transient simulation, and the time-varying control parameter sequence as the input of boundary conditions, the water hammer calculation mathematical model is used to perform time-step recursive calculation to obtain the transient hydraulic parameter sequence of pressure and flow rate at key nodes of the pipeline system during the total calculation time.

[0112] In this embodiment, before starting the dynamic time-step calculation, the technical control parameters for the entire simulation process must be set. This includes: determining the total simulation time, which must be longer than the duration of the main disturbance event and be able to capture the main pressure fluctuation decay process; determining the calculation time step, the selection of which must meet the numerical stability condition Coulomb's condition, which is usually determined based on a combination of pipe length, wave velocity, and accuracy requirements; and inputting the propagation velocity of the pressure wave in the pipeline medium, which depends on the elasticity of the pipe material, the elasticity of the medium, and the pipe diameter and wall thickness, and can be calculated from engineering parameters or directly input.

[0113] The system reads the defined transient simulation scenario script and converts each natural language-described event in the script, such as the accidental shutdown of Pump 1, into an executable event object. Each event object contains an event type identifier, a trigger time, and a set of type-related attribute parameters. For example, a valve closing event object might have the following attribute parameters: valve ID, closing start time, total closing duration, and a pointer to a closing rule function that points to either a linear or two-part function.

[0114] At the start of each time step of the analog clock, the system checks whether any events have been triggered or are in progress at the current time. If so, it calculates the instantaneous control parameter values ​​generated by the event at the current moment according to the logic of the event object. For valve action events, it calculates the current instantaneous opening percentage of the valve based on its closing pattern and the time elapsed, and then obtains the instantaneous local resistance coefficient by querying the valve characteristics. For pump start-stop events, it calculates the current instantaneous speed ratio of the pump based on the start-stop pattern, and derives the instantaneous pump performance curve parameters at the current speed based on the similarity law. These calculated instantaneous values ​​will be used to update the boundary condition equations of the corresponding valve nodes and pump nodes in the hydraulic calculation of the current time step.

[0115] The method of characteristics is used to transform the set of partial differential equations describing unsteady flow within a pipeline into a set of difference equations suitable for iterative computer solution. This process includes: discretizing each pipeline along its length into several computational cross-sectional grids; and discretizing continuous time into the aforementioned time steps. Through mathematical transformation, compatibility equations applicable to each grid point within the pipeline, relating parameters of adjacent time layers, are obtained. Simultaneously, for special nodes in the system such as pumps, valves, pools, and branch points, nodal equations are established based on their physical characteristics, such as energy conservation and flow continuity. The compatibility equations for all internal points and the nodal equations for special nodes together constitute a large set of algebraic equations describing the transient state of the entire system at a certain time step.

[0116] Starting from the initial time t=0, the system state is completely initialized by the steady-state parameters obtained in step S2, and then the time step loop begins: for time layer t, the states of all nodes and pipe segments are known. As time progresses to the t+Δt layer, the boundary condition parameters are updated first. Then, for the new time layer, a large set of algebraic equations is solved simultaneously. Due to the sparse and banded nature of the equations, efficient numerical methods such as the chasing method can be used to solve them. The pressure and flow rates of all grid points in the new time layer are obtained. The pressure and flow rates of key nodes of interest to the user, such as the valve, the midpoint of the pipe, and the pump outlet, are recorded in the time series array. After this time step is completed, the simulation clock advances by one step, and the above process is repeated until the clock reaches the preset total simulation duration. Finally, the complete transient parameter sequence of these key nodes is output, that is, the discrete data point set of the pressure-time curve and the flow-time curve.

[0117] Specifically, step S31: Setting up the calculation conditions to build the numerical stage. This step defines the time and space scales for the entire simulation.

[0118] Total calculation duration: This must ensure that the disturbance process is covered and sufficient attenuation of pressure fluctuations is observed. Example: Assume we plan to simulate a valve closing event within 30 seconds. Considering that the pressure wave will only become insignificant due to friction after propagating back and forth multiple times in the system, the total duration can be set to 60 to 90 seconds. This ensures that the main pressure oscillation process after valve closure is captured.

[0119] Determining the pressure wave velocity: This is a key physical parameter, as it depends on the elasticity of the pipe material, the elasticity of the fluid, and the pipe geometry. Those skilled in the art can look up relevant data such as the material's elastic modulus and the bulk elastic modulus of water based on pipeline engineering parameters like pipe type, diameter, wall thickness, and water temperature. The wave velocity can then be calculated using industry-standard water hammer wave velocity calculation formulas, or directly input based on recommended values ​​from engineering experience manuals and design specifications. For example, for common water transmission steel pipes, the wave velocity range is typically between 800-1200 m / s.

[0120] Determining the time step: To ensure the stability of the numerical simulation and satisfy the Courant condition, the time step must match the spatial step after the pipeline is discretized. Specific implementation method:

[0121] First, discretize all the pipes along their length. For example, if a 200-meter-long pipe is divided into 10 equal segments, then each segment is 20 meters long, and this length is the spatial step size.

[0122] Then, based on the determined pressure wave velocity, ensure that the time step is no greater than the spatial step divided by the wave velocity. Continuing the previous example, if the wave velocity is 1000 m / s, then the time step should be no greater than 0.02 seconds (20 m ÷ 1000 m / s).

[0123] Typically, for convenience, the time step is directly taken as time step = spatial step / wave velocity. This is the conventional approach to satisfy the stability condition.

[0124] Steps S32 and S33: Define the disturbance events and control parameter sequence. This step translates the operation instructions from the physical world into input signals that the computer model can understand.

[0125] Example of objectification and parameterization of events: Valve event: Define a two-stage closing event for outlet valve No. 2. This event object contains the following attributes: event type is valve closing; valve number is V2; trigger start time is the 5th second; total closing time is 30 seconds; the closing pattern is two-stage, with the specific parameters being: 80% closing in the first 15 seconds and the remaining 20% ​​closing in the next 15 seconds.

[0126] Example Pump Event: Define a main pump failure shutdown event (No. 1). This event object includes: event type "pump shutdown"; pump number "P1"; trigger start time "10th second"; shutdown pattern "linear deceleration"; total duration "5 seconds".

[0127] Generate a time-varying sequence of control parameters:

[0128] For valves, during the simulation, the program calculates the valve's opening percentage at each instant based on the event object's description. For example, for the two-stage valve mentioned above, at the 8th second, the valve is in the first stage, and its opening should be 1 - 0.8*(8 / 15). After obtaining the instantaneous opening, the hydraulic characteristic data of the valve, usually presented in tabular or graphical form, describing the resistance coefficients at different openings, can be used to obtain the local resistance coefficient of the valve in the model at the current moment. This dynamically changing sequence of resistance coefficients is the input that drives the changes in the valve's boundary conditions.

[0129] For a pump, the program calculates the percentage speed ratio of the pump's rotational speed relative to its rated speed at each instant, based on the shutdown pattern. For example, if the pump stops after a linear deceleration of 5 seconds, the speed ratio is 1 - 2 / 5 = 0.6 two seconds after triggering. Then, according to the pump similarity law, this speed ratio is used to convert the pump's rated head-flow performance curve, thus obtaining the pump's instantaneous performance curve at the current moment. This dynamically changing performance curve is the input that drives the changes in the pump's boundary conditions.

[0130] Step S34: Establish a mathematical model for water hammer calculation and construct a system equation set. This is the core application of the method of characteristics (MOC), and its purpose is to establish a set of mathematical relationships for the entire pipeline system that can be solved step by step.

[0131] System discretization transforms the schematic diagram of the entire pumping station pipeline system into a mesh model composed of nodes and pipe segments. Each pipe is divided into several small segments, and the segmentation points are the computation nodes. Nodes inside the pipes are called internal points, while the locations of equipment such as pumps, valves, water tanks, and tees are called boundary points or special nodes.

[0132] Establish a compatibility equation for points inside the pipeline. Based on the principle of the method of characteristics, for any calculation node inside the pipeline, its pressure and flow rate at the current moment can be uniquely determined by the pressure and flow rate of its adjacent upstream and downstream nodes at the previous moment through two characteristic lines.

[0133] These two characteristic lines represent the path of pressure wave propagation. The two mathematical relationships derived from them are the compatibility equations, which connect the two unknowns, pressure and flow rate, at the current moment of the same node with the known parameters of the neighboring points at the previous moment.

[0134] Establish boundary condition equations for special nodes, and supplement each special node with an independent equation based on its physical characteristics.

[0135] Valve node: The core equation is the transient head loss equation of the valve, which is the relationship between the pressure difference across the valve and the current instantaneous flow rate and the current instantaneous resistance coefficient. This equation, combined with the compatibility equation from the connecting pipeline, allows us to solve for the pressure and flow rate at the valve.

[0136] Pump node: The core of its equation is the pump's transient head-flow rate relationship, that is, the relationship between the pressure difference between the pump's outlet and inlet at the current moment and the flow rate. This relationship is determined by the instantaneous pump performance curve obtained in step S33. This equation is solved simultaneously with the compatibility equation from the connecting pipeline.

[0137] Pool node: It is generally assumed that the pool has an infinite capacity and a constant water level, so the pressure at this node is a known constant.

[0138] For branch points such as tees: establish the flow continuity equation at that point, where the total inflow equals the total outflow, and the pressure coordination equation for each connecting branch.

[0139] Step S35: Time-step recursive calculation to execute simulation deduction. This step is the dynamic execution process of the model, forming a loop.

[0140] Initialize the steady-state operating parameters obtained in step S2, such as pressure and flow rate of all nodes, to the initial state at time t=0.

[0141] Entering the time step cycle, the time advance will move the analog clock forward by one time step Δt from the current time t, to the new time t+Δt.

[0142] Update the boundary conditions, check if any event has been triggered or is in progress at the new time. If so, according to the logic of step S33, calculate the control parameter values ​​generated by the event at the new time, such as valve resistance coefficient and pump performance curve, and update the relevant parameters in the boundary condition equations of the corresponding node valve and pump.

[0143] The system of equations is constructed and solved. At time t+Δt, corresponding equations, compatibility equations, or boundary condition equations are written for each computational node in the system, including all internal points and special points. All these equations together constitute a large system of linear algebraic equations, whose unknowns are the pressure and flow of all nodes at the new time. This system of equations is sparse and banded; those skilled in the art can use standard numerical methods such as the pursuit method to solve this system of equations efficiently.

[0144] Recording and Storage: After solving the system of equations, the state of the entire system at time t+Δt is obtained. The pressure and flow rates at key nodes of interest to the user, such as the pump outlet, downstream of valves, and high points in the pipeline, are recorded.

[0145] The process of iteratively checking, updating boundaries, solving equations, and recording results continues until the analog clock reaches the total calculation time set in step S31.

[0146] After the loop completes, the system outputs all recorded pressure and flow data for key nodes, arranged in chronological order, thus obtaining the required transient hydraulic parameter sequence. This data can be directly used to plot pressure-time and flow-time curves and to perform water hammer analysis.

[0147] Furthermore, in step S33, when the disturbance event is a two-stage closing operation of the valve, determining the valve closing pattern specifically includes:

[0148] S33a. Obtain the setting parameters for the two-stage closing, including the total time of the fast closing phase, the closing angle of the fast closing phase, the total time of the slow closing phase, and the closing angle of the slow closing phase.

[0149] S33b. During the simulation time-step recursive calculation, determine the relationship between the current cumulative time and the two-stage shutdown setting parameter:

[0150] If the current cumulative time is less than or equal to the total time of the fast closing phase, the closing angle of the valve at the current time step is linearly calculated based on the total time and closing angle of the fast closing phase. If the current cumulative time is greater than the total time of the fast closing phase and less than or equal to the sum of the total time of the fast closing and slow closing phases, the closing angle of the valve at the current time step is linearly calculated based on the total time and closing angle of the slow closing phase. If the current cumulative time is greater than the sum of the total time of the fast closing and slow closing phases, the valve is determined to be in a fully closed state.

[0151] S33c. According to the calculated closing angle of the valve at the current time step, query the characteristic data of the valve resistance coefficient varying with the opening degree, and determine the local resistance coefficient corresponding to the valve at the current time step, which is used to update the valve boundary condition equation in the water hammer calculation mathematical model.

[0152] Among them, in this embodiment, the attribute parameters of the valve closing event object are read. These parameters clearly define two stages of closing: the duration of the first stage of rapid closing and the angle by which the valve needs to rotate and close within this stage; the duration of the second stage of slow closing and the angle by which the valve continues to rotate and close within this stage; the initial opening degree of the valve is usually 100% fully open, and the sum of the closing angles in the two stages is the total closing angle of the valve from fully open to fully closed.

[0153] At each time step of the transient simulation, let the current cumulative simulation time be T, and the system executes a judgment process: First, compare T with the duration of the rapid closing stage T_fast. If T ≤ T_fast, it is determined that the valve is currently in the rapid closing stage. At this time, calculate the current valve angle according to the linear law: current angle = initial angle - (T / T_fast) × rapid closing stage closing angle. Second, if T_fast < T ≤ (T_fast + T_slow), it is determined that the valve is in the slow closing stage. At this time, the current angle = (initial angle - rapid closing stage closing angle) - [(T - T_fast) / T_slow] × slow closing stage closing angle. Finally, if T > (T_fast + T_slow), it is determined that the valve is fully closed, and the current angle is set to 0 or the minimum mechanical angle corresponding to the fully closed position, where T_slow is the duration of the slow closing stage.

[0154] After calculating the real-time angle of the valve at the current time step, use this angle value as the input to query or interpolate the opening degree - resistance coefficient characteristic table defined in step S12 for the valve. This characteristic table describes the local resistance magnitude generated by the valve on the water flow at different opening degrees. Through querying, obtain the local resistance coefficient value ζ(t) that precisely corresponds to the current opening degree. This ζ(t) value will immediately be substituted into the valve node boundary condition equation at the current time step to calculate the flow rate through the valve and the pressure difference on both sides of the valve, thereby truly simulating the throttling effect of the valve on the water flow during the slow closing process and the resulting water hammer pressure change.

[0155] Furthermore, in step S33, when the disturbance event is the accidental shutdown of the pump, determining the rotational speed change law of the pump and the corresponding sequence of head - flow characteristic changes specifically includes:

[0156] S33d. Use the steady - state operating rotational speed of the pump at the moment of accidental shutdown as the initial rotational speed;

[0157] S33e. At each simulation time step, based on the rotational inertia of the pump unit rotor, the pump torque and motor torque corresponding to the pump's operating condition point in the previous time period, calculate the change in pump speed at the current time step to obtain the current pump speed.

[0158] S33f. Based on the similarity principle of pumps, according to the ratio of the current speed to the rated speed, the rated head-flow characteristic curve of the pump is proportionally transformed to obtain the transient head-flow characteristic relationship of the pump at the current time step.

[0159] S33g, Solve the transient head-flow characteristic relationship of the pump under the current time step and the compatibility equation of the pipeline at the pump node to obtain the flow rate through the pump and the pressure difference between the pump inlet and outlet during the current time period, and then calculate the transient pressure value of the pump outlet node.

[0160] In this embodiment, at the instant t=0+ when the accident shutdown event is triggered, the operating state of the pump at that moment is recorded. These states are directly inherited from the steady-state or transient calculation results at the moment before the accident, and key parameters include: the instantaneous speed ω_0 of the pump (usually the rated speed), the instantaneous flow rate Q_0 through the pump, the instantaneous head H_0 generated by the pump, and the instantaneous operating efficiency of the pump used to calculate the hydraulic torque.

[0161] After a pump stops due to an accident, the motor drive torque drops to zero. The change in pump rotor speed is determined by the resultant torque acting on it. Within each tiny simulation time step Δt, the system performs the following calculations: First, based on the pump's operating speed and flow rate at the end of the previous time step, the hydraulic torque M_pump generated by the pump under this condition is calculated. This torque is typically related to head, flow rate, speed, and efficiency. Then, considering the possible residual torque or frictional torque M_friction of the motor (usually a resistance torque), the angular acceleration of the rotor in the current time period is calculated according to the rigid body rotation law: α = (-M_pump - M_friction) / J, where J is the unit's moment of inertia. Finally, the pump speed at the end of the current time step is updated: ω_new = ω_old + α * Δt, where ω_new is the updated pump speed and ω_old is the original pump speed. This process is repeated in each time step, thus simulating the dynamic curve of the speed nonlinearly decaying from the rated value to zero.

[0162] After the pump speed changes, the head-flow characteristic no longer follows the curve at the rated speed. The system uses the pump's full characteristic curve or transforms it using a similarity law. Specifically, the ratio of the current speed ω_new to the rated speed ω_rated is defined as the dimensionless speed α = ω_new / ω_rated. Simultaneously, the current flow rate Q is converted to a dimensionless flow rate ν = Q / (ω_new / ω_rated) or other similarity criteria are used. The system internally stores or describes the pump's dimensionless performance curve (head coefficient-flow coefficient curve) at any speed ratio in function form. Using the current dimensionless flow rate ν and speed ratio α, interpolation or calculation is performed on this curve to obtain the current dimensionless head coefficient. Finally, according to the similarity law formula, the dimensionless head coefficient is restored to the correspondence between the actual head H and flow rate Q at the current speed ω_new, i.e., H = f(Q, ω_new). This yields the transient performance curve of the pump at the transient speed at the current time step.

[0163] The pump transient performance relationship H=f(Q) obtained at the current time step is regarded as a boundary condition equation. Simultaneously, the pump, as an internal branch point in the pipeline network, must satisfy the characteristic line compatibility equations of its upstream and downstream pipelines. The transient performance equation of the pump, the characteristic line equations of the upstream and downstream pipelines are simultaneously solved. The unknowns in this system of equations are: the transient flow rate Q through the pump, the transient pressure H_up at the upstream node of the pump, and the transient pressure H_down at the downstream node of the pump. Solving this system of equations numerically yields the actual operating flow rate of the pump and the pressure values ​​at the pump inlet and outlet at the current time step and current speed. In particular, when the speed is very low, the pump may enter turbine operation or braking operation conditions. Its full characteristic curve ensures that the equations still have reasonable solutions under these extreme conditions, thus simulating complex phenomena such as backflow and reverse flow that may occur after the pump stops.

[0164] Further, referring to Figure 4, step S4 includes:

[0165] S41. Extract steady-state risk indicators from the initial steady-state operating parameters. The steady-state risk indicators include the steady-state operating shaft power of the pump, the steady-state current of the motor, and the maximum and minimum values ​​of the steady-state pressure of the pipeline.

[0166] S42. Extract transient risk indicators from the transient hydraulic parameter sequence. The transient risk indicators include the maximum pressure, minimum pressure, maximum pressure rise rate, maximum pressure fall rate, and the magnitude and duration of flow reversal at key pipeline nodes throughout the transient process.

[0167] S43. Compare the extracted steady-state risk indicators with the preset steady-state safety threshold, and compare the extracted transient risk indicators with the preset transient safety threshold.

[0168] In this embodiment, key indicators for assessing long-term operational safety are automatically identified and extracted from the stored set of initial steady-state operating parameters. These indicators do not include intermediate process quantities but are terminal parameters directly linked to equipment lifespan and system stability. They mainly include: the calculated shaft power of the pump under steady-state conditions, used to determine whether the motor matching is reasonable and whether there is an overload risk; the motor line current estimated based on the shaft power and input voltage, used to assess the load rate of the electrical system; and the steady-state pressure values ​​calculated by scanning all nodes in the entire pipeline, identifying the maximum and minimum values. The former is used to assess the pipeline's pressure margin, and the latter is used to assess whether the required net positive suction head (NPSH) for equipment such as the pump is met.

[0169] Post-processing analysis is performed on the transient parameter sequences of key output nodes to extract characteristic values ​​of quantifiable transient hazard intensity. For each monitored node, such as downstream of a valve or a weak point in the pipeline: First, the pressure data of the entire time series is traversed to find the global maximum positive pressure peak and the global minimum negative pressure peak or lowest pressure. Second, the rate of change of pressure over time is calculated to find the maximum positive rate of pressure increase and the maximum negative rate of pressure decrease, which are related to the frequency of pipeline stress changes and the vibrations that may be caused. For key locations such as pump outlets, the flow time series is analyzed to determine whether negative values, i.e., backflow, occur. If they do, the start time of backflow, the maximum flow rate of backflow, and the total duration of backflow are recorded. These characteristic indicators are the essence extracted from massive amounts of time history data for risk assessment.

[0170] An internal safety threshold database is maintained. This database is not a single value, but rather a set of allowable ranges associated with equipment and components. The comparison process is automatic and parallel: the extracted pump shaft power is compared with the motor's rated power and allowable short-term overload power; the motor current is compared with the motor's rated current; the maximum steady-state pressure is compared with the nominal or design pressure of pressure-bearing components such as pipes, flanges, and valves; the minimum steady-state pressure is compared with the saturated vapor pressure and vaporization pressure of the conveyed medium at the operating temperature, taking into account the pump's required net positive suction head (NPSH); the extracted transient pressure peak is compared with the pipe's test pressure or instantaneous pressure-bearing capacity; the transient pressure trough is compared with the vaporization pressure to determine if liquid column separation is possible; the pressure change rate is compared with empirical thresholds to assess the severity of water hammer; the backflow duration is compared with the pump's allowable reversal time or the system's allowable backflow time; each comparison produces a Boolean result of " / no exceedance" and a quantitative result of how much exceedance.

[0171] Further, step S4 analyzes and predicts security risk events, including comprehensively predicting at least one of the following specific security risk events based on the comparison results:

[0172] S44a. If the steady-state operating shaft power of the pump continuously exceeds the rated power of its matching motor, or the steady-state current of the motor exceeds its rated current, then it is predicted that there is a risk of equipment overload operation.

[0173] S44b. If the minimum pressure at a node in the pipeline during a steady-state or transient process is lower than the vaporization pressure of the transported medium at the current temperature, then it is predicted that there is a risk of cavitation at that node.

[0174] S44c. If the maximum pressure at a node in the pipeline during a transient process exceeds the rated pressure bearing capacity of the pipeline component or pipe material, it is predicted that there is a risk of overpressure damage due to water hammer at that node.

[0175] S44d. If the transient simulation results show that the flow reverses in the pipeline after the pump outlet check valve and the duration exceeds the set threshold, it is predicted that there is a risk of medium backflow impacting the pump reversal.

[0176] S44e. If the pressure fluctuation at critical nodes of the pipeline is too large or the rate of pressure change is too fast, it is predicted that there is a risk of causing severe pipeline vibration or support instability.

[0177] S44f: Based on the predicted risk event type, location, and severity, the risk analysis report generated in step S5 provides corresponding risk level prompts and descriptions of potential consequences.

[0178] In this embodiment, if the comparison result of step S43 shows that the steady-state operating shaft power of the pump continuously exceeds the rated power of its matching motor, or the steady-state current of the motor exceeds its rated current, the system determines that there is a risk of equipment overload operation. The risk location is identified by the corresponding pump unit, and the risk level can be divided according to the overload percentage: slightly exceeding the rated value, moderately exceeding the short-term allowable value, and severely exceeding the equipment limit. The potential consequences are related to motor heating, accelerated insulation aging, or even burnout, as well as mechanical damage that may be caused by excessive pump shaft torque.

[0179] If the comparison result of step S43 shows that the minimum pressure at a certain node in the pipeline, especially the pump inlet or the highest point of the pipeline, under steady state, or the lowest pressure valley value that occurs during the transient process, is lower than the vaporization pressure of the conveyed medium at the current temperature and leaves a certain safety margin, i.e., the effective net positive suction head (NPSH) is lower than the required NPSH, then the system determines that there is a risk of cavitation at that node. The risk level is determined based on the depth and duration of the pressure being lower than the vaporization pressure. Potential consequences include decreased pump performance, noise and vibration, and erosion damage to the impeller and pump casing of the flow-through components.

[0180] If the comparison results in step S43 show that the maximum pressure at a certain node in the pipeline, typically downstream of a valve, at the end of the pipeline, or at a geometric high point, exceeds the rated pressure capacity or design pressure of the pipeline components, joints, or valve bodies at that location during a transient process, then the system determines that there is a risk of overpressure damage due to water hammer at that node; this is one of the core risks in water hammer simulation and prediction. The risk level is comprehensively assessed based on the overpressure amplitude and the sharpness of the pressure peak, combined with the rate of pressure change; the potential consequences indicate serious events such as pipeline rupture, flange leakage, and valve damage that could lead to water outages or even safety accidents.

[0181] If the comparison result in step S43 shows that, in transient simulations such as pump accident shutdown, the flow time series of the pipeline node after the pump outlet check valve exhibits a negative value for reverse flow, and the duration of this reverse flow exceeds the allowable free-reversal time of the pump rotor or the system process-allowed backflow time threshold, then the system determines that there is a risk of medium backflow impacting pump reversal; the risk location is identified as the corresponding pump and its outlet pipeline. The risk level is determined based on the magnitude and duration of the backflow flow; the potential consequences will include the impact damage that pump unit reversal may cause to the motor and gearbox, as well as the impact of backflow on the normal operation of the system.

[0182] If the comparison results in step S43 show that the peak-to-peak pressure fluctuation amplitude at key pipeline nodes is too large, exceeding the empirical threshold based on pipe diameter and support spacing, or the maximum rate of pressure change (water hammer wavefront steepness) is too rapid, the system determines that there is a risk of severe pipeline vibration or support instability. The risk location is typically the entire pipeline or a specific section. This risk may not immediately lead to structural failure, but its long-term effects are significant. The risk level is based on a comprehensive assessment of fluctuation amplitude and frequency. Potential consequences include issues such as loosening of pipeline supports, fatigue failure of connectors, and noise generation.

[0183] All triggered risk assessment results are compiled into a structured risk prediction list. Each record in the list must include at least: a unique risk ID, a risk type such as overpressure failure, the specific location of the risk occurrence such as node number: P-203, located 30 meters from the outlet of pump 2 on the main pipeline, the key indicators on which the assessment was based and their values ​​such as transient pressure peak: 2.5 MPa, the safety threshold violated such as pipeline design pressure: 1.6 MPa, the risk level automatically assessed by the system such as high risk, and a standardized description of the potential consequences. This list is the core data source driving step S5 to generate the final risk analysis report.

[0184] Further, step S5 includes:

[0185] S51. Basic information of the pumping station pipeline system and description of the set operating conditions;

[0186] S52. A summary of the main results of the steady-state hydraulic simulation, including the pump operating point, key node pressure, system efficiency, and hydraulic loss distribution;

[0187] S53. A summary of the main results of the water hammer transient hydraulic simulation, including a description of the simulated disturbance event, the maximum and minimum transient pressure values ​​of key nodes and their occurrence time, and a pressure envelope diagram;

[0188] S54, a list of all security risk events predicted in step S4, with each item specifying the risk type, judgment basis, risk location, and risk level;

[0189] S55. Suggestions for operational or design improvements in response to the predicted security risk events.

[0190] In this embodiment, the report generation date and time of this simulation analysis are included; a brief description of the version or source of the engineering parameter data on which it is based; and a textual description of the specific operating conditions set for this simulation, including a summary of the steady-state target and the transient disturbance event script.

[0191] The core conclusions of the steady-state simulation are presented in the form of tables and key data, including: the total steady-state flow rate reached by the system; the operating point flow rate, head, efficiency, and shaft power of each operating pump; the motor input current; the system head utilization rate; and most importantly, the hydraulic losses of the whole system are listed, including the values ​​and proportions of friction loss and local loss, and the overall energy efficiency assessment of the system under this operating condition is given. This chapter aims to illustrate the baseline of the system's economic and safety performance under normal operating conditions.

[0192] The simulated transient scenario is described in detail. First, the sequence of disturbance events is reiterated in words. Second, the transient response is presented using graphs as the core: at least three key nodes are provided, such as the pressure curves of the downstream valve, the midpoint of the pipeline, and the outlet over time, i.e., the water hammer process line; a pressure envelope diagram of the entire pipeline is provided, which marks the highest and lowest pressures reached at each point along the pipeline during the transient process, forming two envelope curves; finally, the transient pressure extremes, maximum and minimum pressures, and the specific simulated times of occurrence at each key monitoring point are listed in a statistical table.

[0193] The generated risk prediction list is presented in a clear and eye-catching table format, displaying all items one by one. Each table column includes at least: serial number, risk type, risk location, risk level (colors such as red / yellow / green), and measured / threshold values ​​of key judgment indicators. This section makes all predicted risks readily apparent, allowing users to quickly grasp the key points.

[0194] The report provides a comprehensive conclusion outlining the overall safety status of the system under the current operating conditions. Then, for each medium- or high-risk item listed in S54, specific and actionable improvement recommendations are provided. These recommendations should not be general but rather provide directional guidance based on simulation results; for example, for overpressure risk, recommendations could include extending the closing time of valve VP-101 to at least 20 seconds or considering adding a pressure tank near node P-203; for cavitation risk, recommendations could include raising the minimum operating water level in the inlet pool by 0.5 meters or verifying whether the required net positive suction head (NPSH) of the pump is met. These recommendations directly link the simulation analysis to engineering practice, enhancing the report's practical value.

[0195] Furthermore, the operational or design improvement suggestions proposed in step S55 include at least one of the following:

[0196] S55a. In response to the predicted risk of severe water hammer overpressure caused by rapid valve closure, it is recommended to adjust the valve closure pattern, extend the closure time, or adopt a two-stage closure strategy, and re-simulate and verify the optimization effect based on this method.

[0197] S55b. In response to the predicted risk of low pressure or backflow caused by pump accident shutdown, it is recommended to add a slow-closing check valve or hydraulic check valve at the pump outlet, and to re-predict the safety risks of the system after the addition of the equipment based on this method.

[0198] S55c. In response to the predicted risks of general pressure fluctuations and vibrations, it is recommended to add air valves, pressure regulating towers, or water hammer eliminators at specific locations in the pipeline, and to re-simulate the modified system based on this method to assess the degree of risk mitigation.

[0199] In this embodiment, if a severe pressure rise is predicted due to the rapid closure of valves, especially the main outlet valve or pump outlet valve, the system will generate optimization suggestions to adjust the valve operation pattern. Specifically, this might be: Valve V-001 is detected to be fully closed within 5 seconds, causing the downstream node pressure peak to exceed the limit. Suggestion: Extend the total closing time to 15 seconds and adopt a two-stage closing strategy. Recommended parameters: 60% fast closure in the first 3 seconds, followed by a slow closure of the remaining 40% in the next 12 seconds. After adopting this suggestion, the user can modify the corresponding operating condition settings in the software and rerun the simulation to verify the optimization effect. This suggestion directly links the specific risk cause with the specific modification of operating parameters.

[0200] If a significant pressure drop in the pump outlet pipeline after a pump failure is predicted, potentially leading to water column separation or continuous backflow, the system will generate a recommendation to add protective equipment. For example, if the prediction indicates that backflow in the outlet pipeline of pump 1 will exceed 2 seconds after a power outage, the recommendation is to add a hydraulically controlled slow-closing check valve after the check valve at the pump 1 outlet. This valve can quickly close to prevent backflow in the initial stage of pump shutdown and slowly close in the final stage to reduce water hammer pressure rise. After initially selecting a model, the user can update the valve characteristic parameters in the software and re-simulate the pump shutdown water hammer to evaluate the protection effect. This recommendation guides the user through iterative design and verification.

[0201] If the prediction results show that there are severe pressure fluctuations in multiple parts of the pipeline, indicating a widespread risk of vibration, the system will generate a recommendation to consider adding flexible energy absorption devices to the system. For example, if the simulation shows that the pressure fluctuation is large between nodes P-150 and P-200 in the middle section of the pipeline, the system may recommend: consider adding a composite exhaust and intake valve at a high point near node P-170 to allow air intake to prevent water column separation under negative pressure and exhaust air under positive pressure; or, evaluate the feasibility of adding a small pressure regulating tower near node P-180. These measures can effectively dampen pressure fluctuations. Users can add these devices as new boundary conditions to the model and re-simulate to quantify their vibration reduction effect. This recommendation provides users with an expanded design approach from passive prediction to active protection.

[0202] According to a second embodiment of the present invention, the present invention claims protection for a safety risk prediction system for a pumping station pipeline system, comprising:

[0203] One or more processors;

[0204] A memory storing one or more programs, which, when executed by one or more processors, cause the one or more processors to implement the aforementioned safety risk prediction method for a pumping station pipeline system.

[0205] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0206] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units. The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0207] The specific embodiments of the invention have been described in detail above, but they are only examples, and this application is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the invention are also within the scope of this application. Therefore, all equivalent changes, modifications, and improvements made without departing from the spirit and principles of this application should be covered within the scope of this application.

Claims

1. A method for predicting safety risks in a pumping station pipeline system, characterized in that, The method includes the following steps: S1, obtaining the engineering parameters and operating condition setting parameters of the target pumping station pipeline system; S2, based on the engineering parameters and operating condition setting parameters, performing steady-state hydraulic simulation on the pumping station pipeline system to calculate the initial steady-state operating parameters of the system under the set operating conditions; S3, based on the engineering parameters, operating condition setting parameters, and the initial steady-state operating parameters, setting a disturbance event, and performing water hammer transient hydraulic simulation on the pumping station pipeline system to calculate the transient hydraulic parameter sequence of key nodes of the pipeline system under the disturbance event; S4, based on the initial steady-state operating parameters and the transient hydraulic parameter sequence, analyzing and predicting the potential impact of the pumping station pipeline system under the set operating conditions and disturbance events. S5. Generate and output a risk analysis report containing the predicted results of the safety risk events and their corresponding operating conditions; Step S2 includes: S21. Based on the engineering parameters, determine the topology, component composition, and geometric parameters of the pumping station pipeline system; S22. Based on the operating condition setting parameters, determine the initial operating flow rate and head of the pumps in the system; S23. Based on the initial operating flow rate and head of the pumps, combined with the topology and resistance characteristics of the pipeline system, calculate the pump shaft power, motor current, pressure and flow rate before and after each valve in the pipeline, pipeline friction loss, local loss, total hydraulic loss, and outlet pressure during steady-state operation; S24. Based on the calculated pipeline pressure... Force distribution data is used to generate and store the pressure distribution curve along the pipe length from the pump outlet to the end of the pipeline, as part of the initial steady-state operating parameters; Step S3 includes: S31, based on the engineering parameters and the initial steady-state operating parameters, setting the calculation conditions for water hammer simulation, the calculation conditions including the total calculation time, the calculation time step, and the wave velocity of the pressure wave in the pipeline; S32, defining disturbance events as the causes of water hammer simulation, the disturbance events including pump start-up, normal pump shutdown, pump accident shutdown, linear valve closure operation, two-stage valve closure operation, or accidental fast valve closure; S33, according to the defined disturbance events, determining the time-varying control parameter sequence in the disturbance events, for valve closure events, determining... S34. Determine the valve closing pattern and corresponding resistance coefficient change sequence; for pump start-up and shutdown events, determine the pump speed change pattern and corresponding head-flow characteristic change sequence; S35. Based on the method of characteristics, establish a water hammer calculation mathematical model for the pumping station pipeline system. The model includes basic characteristic equations describing transient flow in the pipeline and boundary condition equations describing pumps, valves, and inlet / outlet water tanks; S36. Using the initial steady-state operating parameters as the initial conditions for transient simulation and the time-varying control parameter sequence as the input of boundary conditions, use the water hammer calculation mathematical model to perform time-step recursive calculations to obtain the transient hydraulic parameter sequence of pressure and flow rate at key nodes of the pipeline system during the total calculation time.Step S4 includes: S41, extracting steady-state risk indicators from the initial steady-state operating parameters, the steady-state risk indicators including the steady-state operating shaft power of the pump, the steady-state current of the motor, and the maximum and minimum steady-state pressure of the pipeline; S42, extracting transient risk indicators from the transient hydraulic parameter sequence, the transient risk indicators including the maximum and minimum pressure values, the maximum rate of pressure increase, the maximum rate of pressure decrease, and the magnitude and duration of flow reversal at key pipeline nodes throughout the transient process; S43, comparing the extracted steady-state risk indicators with preset steady-state safety thresholds, and comparing the extracted transient risk indicators with preset transient safety thresholds.

2. The safety risk prediction method for a pumping station pipeline system according to claim 1, characterized in that, Step S1 includes: S11, obtaining pump performance parameters, including rated flow rate, rated head, rated speed, high-efficiency range, shaft power characteristic curve or data, and pump moment of inertia; S12, obtaining valve parameters, including valve type, nominal diameter, local resistance coefficient in fully open state, and characteristic data of resistance coefficient variation with opening degree or flow direction for regulating valves or check valves; S13, obtaining inlet and outlet pipeline parameters, including material, inner diameter, wall thickness, length, installation height, friction coefficient of each pipe section, and local resistance coefficient of elbows, tees, and reducers in the pipeline. S14. Obtain inlet and outlet boundary condition parameters, including the design water level and amplitude of the inlet pool, the design water level and pressure of the outlet pool or outlet point, and whether the boundary is a constant water level or has a time-varying pattern; S15. Obtain medium parameters and environmental parameters, including the density and temperature of the transported liquid, and the environmental parameters including the local gravitational acceleration; S16. Obtain operating condition setting parameters, including the target operating flow rate or head setting value of the pump in the steady-state simulation, the initial opening setting value of the valve, and the type and parameters of the planned disturbance event in the water hammer simulation.

3. The safety risk prediction method for a pumping station pipeline system according to claim 2, characterized in that, In step S33, when the disturbance event is a two-stage valve closing operation, determining the valve closing pattern specifically includes: S33a, obtaining the setting parameters for the two-stage closing, including the total time of the fast closing phase, the closing angle of the fast closing phase, the total time of the slow closing phase, and the closing angle of the slow closing phase; S33b, during the simulated time-step recursive calculation, determining the relationship between the current accumulated time and the two-stage closing setting parameters: if the current accumulated time is less than or equal to the total time of the fast closing phase, then linearly calculating the valve closing time at the current time step based on the total time and closing angle of the fast closing phase. Closing angle; if the current cumulative time is greater than the total time of the fast closing phase and less than or equal to the sum of the total time of the fast closing and slow closing phases, then the closing angle of the valve at the current time step is linearly calculated based on the total time of the slow closing phase and the closing angle; if the current cumulative time is greater than the sum of the total time of the fast closing and slow closing phases, then the valve is determined to be in a fully closed state; S33c, based on the calculated closing angle of the valve at the current time step, the characteristic data of the valve resistance coefficient changing with the opening degree is queried to determine the local resistance coefficient of the valve at the current time step, which is used to update the valve boundary condition equation in the water hammer calculation mathematical model.

4. The safety risk prediction method for a pumping station pipeline system according to claim 3, characterized in that, In step S33, when the disturbance event is a pump accident shutdown, determining the pump speed change pattern and the corresponding head-flow characteristic change sequence specifically includes: S33d, using the pump's steady-state operating speed at the moment of accident shutdown as the initial speed; S33e, at each simulation time step, calculating the change in pump speed at the current time step based on the pump unit rotor's moment of inertia, the pump torque and motor torque corresponding to the pump's operating condition point in the previous time period, to obtain the pump's current speed; S33f, based on the pump's similarity principle, proportionally transforming the pump's rated head-flow characteristic curve according to the ratio of the current speed to the rated speed, to obtain the pump's transient head-flow characteristic relationship at the current time step; S33g, solving the pump's transient head-flow characteristic relationship at the current time step and the compatibility equation of the pipeline at the pump node simultaneously to obtain the flow rate through the pump and the pressure difference between the pump inlet and outlet during the current time period, and then calculating the transient pressure value at the pump outlet node.

5. The safety risk prediction method for a pumping station pipeline system according to claim 4, characterized in that, Step S4 analyzes and predicts safety risk events, including comprehensively predicting at least one of the following specific safety risk events based on comparison results: S44a, if the steady-state operating shaft power of the pump continuously exceeds the rated power of its matching motor, or the steady-state current of the motor exceeds its rated current, then an overload operation risk is predicted; S44b, if the minimum pressure at a node in the pipeline during steady-state or transient processes is lower than the vaporization pressure of the conveyed medium at the current temperature, then a cavitation risk is predicted at that node; S44c, if the maximum pressure at a node in the pipeline during transient processes exceeds the rated pressure bearing capacity of the pipeline assembly or pipe material. If the transient simulation results show that the flow reverses in the pipeline after the pump outlet check valve and the duration exceeds the set threshold, it is predicted that there is a risk of medium backflow impacting the pump reversal; if the pressure fluctuation amplitude or pressure change rate of the key pipeline node is too large, it is predicted that there is a risk of causing severe pipeline vibration or support instability; according to the predicted risk event type, location and severity, the risk analysis report generated in step S5 provides the corresponding risk level prompts and potential consequences descriptions.

6. The safety risk prediction method for a pumping station pipeline system according to claim 1, characterized in that, Step S5 includes: S51, basic information of the pumping station pipeline system and a description of the set operating conditions; S52, a summary of the main results of the steady-state hydraulic simulation, including the pump operating point, key node pressure, system efficiency, and hydraulic loss distribution; S53, a summary of the main results of the water hammer transient hydraulic simulation, including a description of the simulated disturbance events, the maximum and minimum transient pressure values ​​of key nodes and their occurrence time, and a pressure envelope diagram; S54, a list of all safety risk events predicted in step S4, with each item specifying the risk type, judgment basis, risk location, and risk level; S55, operational or design improvement suggestions for the predicted safety risk events; the operational or design improvement suggestions proposed in step S55... The improvement recommendations should include at least one of the following: S55a. For the predicted risk of severe water hammer overpressure caused by rapid valve closure, it is recommended to adjust the valve closure pattern, extend the closure time, or adopt a two-stage closure strategy, and re-simulate and verify the optimization effect based on this method; S55b. For the predicted risk of low pressure or backflow caused by pump accident shutdown, it is recommended to add a slow-closing check valve or a hydraulically controlled check valve at the pump outlet, and re-predict the safety risks of the system after adding the equipment based on this method; S55c. For the predicted risk of general pressure fluctuations and vibrations, it is recommended to add an air valve, pressure regulating tower, or water hammer eliminator at specific locations in the pipeline, and re-simulate the modified system based on this method to assess the degree of risk mitigation.

7. A safety risk prediction system for a pumping station pipeline system, characterized in that, include: One or more processors; A memory having stored one or more programs that, when executed by one or more processors, cause the one or more processors to implement a safety risk prediction method for a pumping station pipeline system according to any one of claims 1 to 6.

Images