Valve control method and system for water hammer protection of a water delivery line

Abstract

This invention relates to the field of water pipeline control technology, specifically to a valve control method and system for water hammer protection in water pipelines. The method includes: obtaining the pipe segment length and the time difference of pressure wave arrival between adjacent nodes of the water pipeline to obtain the actual pressure wave velocity; calculating the expected arrival time of the negative pressure reflected wave at each high point and the water hammer half-wave width, defining the dangerous phase window, and forming a reflected wave time sequence spectrum; assigning differentiated values ​​to the valve closing rate to obtain a dynamic closing curve; reading the real-time pressure value, and increasing the compensation amount when it is lower than the lower limit of the safe pressure. This invention achieves active phase separation between the valve closing action and the negative pressure reflected wave phase, effectively reducing the conditions for water hammer formation due to flow interruption and improving the safety margin of pipeline operation.

Description

Technical Field

[0001] This application relates to the field of water pipeline control technology, specifically to a valve control method and system for water hammer protection of water pipelines. Background Technology

[0002] In long-distance water transmission projects, pipelines often need to cross multiple mountain ridges and high points, forming a continuous undulating longitudinal profile. Under normal operation, the water flow in each section of such pipelines is in a full-pipe pressurized state, and the pressure distribution along the pipeline is closely related to the terrain elevation difference. Once a sudden power outage of the pump unit or an emergency closure of the terminal valve occurs, the flow velocity in the pipeline changes abruptly, generating an initial positive pressure water hammer wave at the valve, which propagates upstream in the form of a pressure wave.

[0003] To suppress water hammer hazards, it is common practice to pre-install a segmented linear valve closing curve in the controller and use slow-closing valve control to reduce the rate of flow rate change by extending the closing time. This effectively reduces the initial water hammer pressure peak while ensuring pipeline operation continuity.

[0004] Because the pipe lengths from each high point to the valve are different, the arrival times of the negative pressure reflected waves at the valves vary. This phenomenon may affect the perception of the timing structure by the solidified shut-off curve, causing its shut-off action to potentially fall precisely within the time window of a negative pressure reflected wave arriving at the valve. In this case, the continued shut-off action of the valve will further intensify the negative pressure at that point, causing the pressure inside the pipe at the high point to drop below the vaporization pressure of water, triggering a localized flow interruption and the formation of cavitation. If a subsequent positive pressure wave arrives, the cavitation will instantly close, generating a flow interruption and cavitation water hammer that is far more severe than the initial water hammer, potentially leading to the bursting of long-distance water pipelines. Summary of the Invention

[0005] To address the existing technical problem that the valve's fixed closing curve cannot avoid the dangerous phase of negative pressure reflection waves in long-distance, multi-elevation water pipelines, thus inducing flow interruption and water hammer, this application provides a valve control method and system for water hammer protection in water pipelines.

[0006] In a first aspect, this application provides a valve control method for water hammer protection of a water pipeline, comprising: acquiring the pipe segment length and the time difference of pressure wave arrival between adjacent nodes of the water pipeline; obtaining the actual pressure wave velocity based on the pipe segment length and the time difference; acquiring the pipe segment length from each high point to the end valve; using the actual pressure wave velocity and the pipe segment length from each high point to the end valve, calculating the expected time of arrival of the negative pressure reflected wave at each high point and the water hammer half-wave width; defining a dangerous phase window before and after the expected time based on the water hammer half-wave width; superimposing the dangerous phase windows of all high points on the time axis to form a reflected wave time sequence map; assigning differentiated values ​​to the valve closing rate in each time period of the entire valve closing process according to the reflected wave time sequence map to obtain a dynamic closing curve; during the execution of the dynamic closing curve, reading the real-time pressure value of each high point sensor; and, in response to the real-time pressure value being lower than the lower limit of the safe pressure, sending a back-opening control signal to the valve actuator to increase the valve opening by a compensation amount based on the current value.

[0007] By constructing the arrival time sequence map of reflected waves at each high point using real-time pressure wave velocity, and by using a differentiated assignment method for valve closing rate, real-time compensation feedback is provided for negative pressure at high points. This effectively reduces the formation conditions of water hammer caused by flow interruption while ensuring the continuity of pipeline operation, thus significantly improving the pipeline's operational safety margin and anti-burst capability under accident conditions.

[0008] Preferably, the step of obtaining the pipe segment length and pressure wave arrival time difference between adjacent nodes of the water pipeline, and obtaining the actual pressure wave velocity based on the pipe segment length and the time difference, includes: deploying high-frequency pressure sensor nodes at the pump station outlet, before and after each high point, and at the end valve of the water pipeline; uploading the collected pressure time series data to the control unit in real time through each sensor node; extracting the pressure wave arrival time difference between two nodes by performing cross-correlation calculation on the pressure time series data of adjacent nodes according to the control unit; and dividing the known pipe segment length between adjacent nodes by the measured time difference to obtain the actual pressure wave velocity under the current operating condition.

[0009] The actual pressure wave velocity under the current operating conditions is obtained by directly dividing the known length of the pipe section by the measured time difference. This method effectively reduces the systematic deviation caused by relying on the design nominal value while ensuring the acquisition of the true hydraulic state.

[0010] Preferably, the step of calculating the expected time when the negative pressure reflected wave at each high point reaches the valve and the water hammer half-wave width using the actual pressure wave velocity and the pipe length from each high point to the end valve includes: responding to the end valve receiving a shut-off start signal and recording the start time; calculating the expected time when the negative pressure reflected wave at each high point reaches the valve after propagating through the pipeline from the high point based on the start time, the pipe length from each high point to the end valve, and the actual pressure wave velocity; and dividing the pipe length from each high point to the end valve by the actual pressure wave velocity to obtain the water hammer half-wave width corresponding to each high point.

[0011] Preferably, the step of superimposing the dangerous phase windows of all high points on the time axis to form a reflected wave time sequence map includes: superimposing the dangerous phase windows of all high points on the time axis to form a complete reflected wave time sequence map, and marking all dangerous periods that need to be avoided during the entire valve closing process in the generated reflected wave time sequence map; in response to the overlap of dangerous phase windows of two adjacent high points on the time axis, taking the union of the two windows as the merged dangerous period.

[0012] The arrival time of the negative pressure reflected wave is estimated by the pipe length from each high point to the valve, and a complete reflection wave time sequence map is formed by defining the dangerous phase window based on the half-wave width of water hammer. This effectively reduces the risk of negative pressure while ensuring that accurate time coordinates are provided.

[0013] Preferably, the step of assigning differentiated values ​​to the valve closing rate in each time period of the entire valve closing process based on the reflected wave time sequence spectrum to obtain a dynamic closing curve includes: driving the valve to operate at a high closing rate in response to the interval marked as a safe period in the time sequence spectrum; switching the valve closing rate to an extremely slow mode approaching zero in response to the interval marked as a dangerous phase window in the time sequence spectrum, so that the valve opening remains approximately constant during the window; and automatically restoring to the normal closing rate of the safe period in response to the end of the dangerous phase window.

[0014] This achieves active phase separation between the valve closing action and the negative pressure reflected wave, thereby effectively reducing the superposition and amplification of the negative pressure reflected wave by the valve closing action while ensuring that the total closing time is controllable.

[0015] Preferably, the step of reading the real-time pressure values ​​of each high-point sensor, in response to the real-time pressure value being lower than the safety pressure lower limit, includes: acquiring the vaporization pressure and safety margin corresponding to the water temperature at the high point; when sufficient historical pressure sequence data is available, acquiring the maximum and minimum values ​​of the historical pressure sequence under normal operating conditions, and using the difference between the maximum and minimum values ​​as the safety margin; combining the vaporization pressure and the safety margin to obtain the safety pressure lower limit; and comparing the real-time pressure value with the safety pressure lower limit.

[0016] Preferably, the step of sending a back-opening control signal to the valve actuator to increase the valve opening by a compensation amount based on the current value includes: obtaining the rated maximum angular velocity and single-step control cycle given by the valve actuator; multiplying the rated maximum angular velocity by the single-step control cycle to obtain the maximum allowable change in valve opening within a single control cycle; calculating the deviation between the lower limit of safety pressure and the real-time pressure value; calculating the difference between the lower limit of safety pressure and the vaporization pressure as the total width of the safety margin band; and calculating the compensation amount based on the deviation, the total width of the safety margin band, and the maximum change in opening.

[0017] Preferably, after calculating the compensation amount based on the deviation, the total width of the safety margin band, and the maximum opening change, the method further includes: in response to the real-time pressure value falling below the vaporization pressure, forcibly applying an upper limit constraint to the compensation amount; and setting the compensation amount as the maximum opening change.

[0018] Preferably, after sending a back-opening control signal to the valve actuator and increasing the valve opening by a compensation amount based on the current value, the method further includes: continuously monitoring the recovery trend of the pressure at the high point using the sensor sampling period as the beat; determining that the pressure recovery has entered a new steady state in response to the real-time pressure value rising back above the lower limit of the safe pressure and the stable duration not less than the half-wave width of the water hammer corresponding to the high point; canceling the back-opening compensation so that the valve resumes executing the dynamic closing curve.

[0019] In a second aspect, this application provides a valve control system for water hammer protection of water pipelines, comprising: a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the aforementioned valve control method for water hammer protection of water pipelines is implemented.

[0020] By adopting the above technical solution, a computer program is generated for the valve control method of water hammer protection for water pipelines, and stored in the memory so that it can be loaded and executed by the processor. Terminal equipment is then made based on the memory and the processor for convenient use.

[0021] Through a dual-channel control structure with parallel feedforward and feedback, the feedforward channel actively avoids dangerous phases based on the time sequence diagram, while the feedback channel passively corrects residual risks based on the measured pressure deviation. Together, they ensure that the pressure at each high point does not fall below the vaporization pressure threshold throughout the valve closure process, thus eliminating the triggering conditions for water hammer caused by flow interruption.

[0022] Furthermore, by decomposing the lower limit of safety pressure and using the relative position of the pressure deviation within the safety margin zone to drive the compensation amount and the water hammer half-wave width as the stabilization time threshold, a real-time response to the risk of negative pressure at high points is achieved. This effectively reduces the risk of negative pressure at high points while ensuring effective compensation for the residual error that may exist in the feedforward time series spectrum under extreme working conditions. Attached Figure Description

[0023] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0024] Figure 1 A flowchart of a valve control method for water hammer protection of a water pipeline provided in this application embodiment;

[0025] Figure 2 This is a comparison chart of the lowest pressure during the entire closing process of the valves at various high points in the embodiments of the present invention and the existing methods. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] This invention discloses a valve control method for water hammer protection of water pipelines, referring to... Figure 1 This includes steps S1-S4:

[0029] S1. Extract the propagation time sequence characteristics of pressure waves.

[0030] In an optional embodiment, high-frequency pressure sensor nodes are deployed at the pump station outlet, before and after each high point, and at the end valve of the water pipeline, and the sampling frequency is set to... The duration of the water hammer wave rise edge is set based on the pipeline's rated flow velocity and pipe diameter, for example. The value can be 128Hz. The pressure time-series data collected by each sensor node is uploaded to the control unit in real time. The control unit then performs cross-correlation calculations on the pressure time-series data from adjacent nodes to extract the time difference in pressure wave arrival between the two nodes. .

[0031] Based on the known pipe segment lengths between adjacent nodes Time difference from actual measurement The actual pressure wave velocity under the current operating conditions can be obtained: ,in, The measured wave velocity is given in m / s.

[0032] Furthermore, the measured wave velocity and sampling period This will serve as the basis for all subsequent time-series calculations and will be continuously updated as the pipeline's operating status changes. The closer the measured wave velocity value is to the nominal wave velocity of the pipe, the lower the dissolved gas content inside the pipe, and the more stable the hydraulic state. If the measured wave velocity value is too low, it indicates that the gas content inside the pipe is too high, and there is an abnormality in the pipeline's hydraulic state, which needs to be further analyzed in conjunction with high-point pressure data.

[0033] In this way, by continuously updating the measured wave velocity, the time series data always reflects the true hydraulic state of the pipeline, effectively reducing the systematic deviation caused by relying on the design nominal value.

[0034] S2. Construct a time series map of reflected waves based on longitudinal section data.

[0035] In an optional embodiment, the control unit identifies the location of each high point along the pipeline based on the pipeline's longitudinal profile elevation data, and records the pipe length from each high point to the end valve. ,in , This represents the total number of high points. It responds to the end valve receiving a close / start signal and records the start time. The control unit utilizes the pressure wave velocity that has been measured. Calculate the expected time for the negative pressure reflected wave at each high point to travel from the high point, through the pipeline, and reach the valve:

[0036]

[0037] in, For the first The negative pressure reflected wave at the highest point arrives at the valve at the expected time. For pressure waves at the valve and the first The time required for one round trip between high points is the water hammer phase corresponding to that high point.

[0038] Next, in each Before and after, the half-wave width of the water hammer corresponding to that high point. Based on this, define the dangerous phase window. According to classical water hammer theory, the one-way propagation time of a pressure wave between the valve and the high point is equal to the inherent half-wave width of the reflected waveform at that high point. Therefore... Directly from the measured wave speed The length of the pipe section from the high point to the valve Given by the following formula:

[0039]

[0040] This method of selection conforms to the inherent physical properties of water hammer waveforms and is consistent with the currently measured wave velocity. Real-time binding ensures that the method still works even when the pipeline is first put into operation and when no historical data is available.

[0041] Furthermore, the dangerous phase windows of all high points are superimposed on the time axis to form a complete reflected wave time series map, and all dangerous periods that need to be avoided during the entire valve closure process are marked in the generated reflected wave time series map. In response to the overlap of dangerous phase windows of two adjacent high points on the time axis, the control unit takes the union of the two windows as the method for merging dangerous periods, using the most conservative boundary as the standard to ensure that the negative pressure risk of any high point is not missed due to misjudgment of the window boundary. It should be noted that there are many other ways to achieve window merging in the art, and those skilled in the art can choose different merging methods according to actual needs.

[0042] In this way, the arrival time of the negative pressure reflected wave can be objectively estimated based on the pipe length from each high point to the valve, and the dangerous phase window can be defined based on the water hammer half-wave width, forming a complete reflection wave time series map, which provides an accurate time coordinate basis for subsequent differential rate assignment.

[0043] S3. Assign differentiated values ​​to the shutdown rate based on the time sequence graph.

[0044] In an optional embodiment, the process of the valve going from fully open to fully closed is divided into several time periods by the control unit, and the valve closing rate in each time period is differentiated according to the generated reflection wave time sequence spectrum, thereby obtaining a dynamic closing curve, replacing the original fixed piecewise linear curve.

[0045] In response to periods marked as safe in the time-series diagram, the control unit drives the valve to operate at a high closing rate, rapidly reducing the valve opening and flow velocity within the pipe, thereby compressing the energy amplitude of the negative pressure reflected waves at subsequent high points. The upper limit of the closing rate within the safe period is constrained by the flow velocity change rate corresponding to the current valve opening not exceeding the allowable pressure rise value of the initial positive pressure water hammer. The allowable pressure rise value is the difference between the pipeline pressure test pressure and the current static water pressure. The pipeline pressure test pressure is 1.3 times the pipeline's rated working pressure, directly given in the pipe manufacturer's technical documents according to current pipeline design and acceptance specifications.

[0046] Response to a phase window marked as dangerous in the time series graph Within the specified range, the control unit switches the valve closing rate to an extremely slow mode approaching zero, keeping the valve opening approximately constant during this window. Since the valve opening remains constant, the rate of change of flow velocity in the pipe approaches zero, and no new pressure disturbance is superimposed at the valve. This prevents the negative pressure reflection wave from being further amplified when passing through the valve, effectively cutting off the path for the formation of water hammer and preventing flow interruption.

[0047] Furthermore, in response to the end of the dangerous phase window, the control unit automatically resumes the normal closing rate during the safe period and continues the closing process. The entire dynamic closing curve exhibits a stepped alternating pattern of fast, slow, fast, slow, with its rhythm determined by the water hammer effect at each high point. Compared to the fixed closing curve, which uses a uniform rate of abrupt change throughout, this stepped alternating pattern provides a gradual transition, avoiding the overlap of the active closing period and the arrival period of the negative pressure reflected wave on the time axis.

[0048] In this way, by dividing the entire valve closing process into safe periods and dangerous phase windows, and assigning two different rate values ​​to high-speed closing and extremely slow holding respectively, the valve closing action and the negative pressure reflected wave phase are actively staggered, effectively reducing the superposition and amplification of the negative pressure reflected wave by the valve closing action.

[0049] S4. Trigger opening compensation for high-point negative pressure conditions.

[0050] In an optional embodiment, during the execution of the dynamic shutdown curve, the control unit continuously reads the real-time pressure values ​​from each high-point sensor. and the lower limit of safe pressure at that high point. Comparison, It is necessary to consider the vaporization pressure corresponding to the water temperature at that high point. and safety margin Among them, vaporization pressure The water temperature is obtained in real time from the pipeline water temperature sensor; safety margin. Take the peak-to-trough fluctuation range of the pressure time series during the historical normal operating period at this high point, that is, the maximum value of the historical pressure series under normal operating conditions. and minimum value The difference. When historical pressure sequence data is insufficient, for example, the number of valid historical sampling points is less than the number of sampling points corresponding to a complete running cycle. A preset percentage of the pipeline's rated working pressure at the high point is taken as the initial safety margin. For example, 5% of the rated working pressure can be used. After sufficient historical data is accumulated, it will automatically switch to the historical peak-valley difference.

[0051]

[0052] This range reflects the inherent pressure fluctuation range at this high point under normal water supply conditions caused by routine disturbances such as flow regulation and user water intake.

[0053] Responding to real-time pressure at a certain high point Below The control unit determines that there is a risk of flow interruption at this high point and sends a brief back-opening control signal to the valve actuator, increasing the valve opening by a compensation amount based on the current value. :

[0054]

[0055] The numerator represents the deviation between the measured pressure and the lower safety limit, while the denominator represents the total width of the safety margin band. The ratio of the two reflects the relative position of the current negative pressure level within the safety margin band, resulting in a positive correlation between the compensation amount and the degree of danger. The rated maximum angular velocity is also included. The unit should be consistent with the unit of valve opening. For example, if the valve opening is measured in degrees (°), then... The unit is ° / s, and the single-step control cycle is... The unit is s, therefore The unit is °, and the compensation amount is... The unit is consistent with the valve opening degree.

[0056] The maximum allowable change in valve opening within a single control cycle is determined by the rated maximum angular velocity given on the valve actuator nameplate. With single-step control cycle Direct multiplication yields:

[0057]

[0058] This value is constrained by the mechanical response limits of the valve actuator and is an inherent parameter of the equipment from the factory; when Break This indicates that the pipeline has been subjected to a disturbance significantly exceeding the normal negative pressure range, signifying the most critical condition where cavitation has occurred. At this point, the control unit forcibly shuts down the pipeline. An upper limit constraint is imposed. Because under this condition the aforementioned ratio will necessarily be greater than 1, the result calculated according to the relational formula is... Greater than Therefore, take The excess portion is continuously compensated by subsequent control cycles, thus avoiding the impact of a single-step opening jump on the actuator.

[0059] Furthermore, after the compensation action is executed, the control unit uses a pre-determined sensor sampling period. To maintain the rhythm, continuously monitor the recovery trend of the pressure at this high point. In response to... Rebound to The above conditions must be met, and the duration of stable operation must be no less than the half-wave width of the water hammer corresponding to that high point. That is, at least lasting During each sampling cycle, the control unit determines that the pressure has recovered to a new steady state and cancels the back-open compensation, causing the valve to resume executing the dynamic closing curve. This steady-state determination time is directly tied to... and The derived This ensures that the stability assessment time covers a complete half-cycle of the reflected wave, avoiding the misjudgment of transient recovery as steady-state recovery.

[0060] The aforementioned compensation judgment and the execution of the main closing curve form a dual-channel control structure with feedforward and feedback in parallel. The feedforward channel actively avoids dangerous phases based on the time sequence diagram, while the feedback channel passively corrects residual risks based on the measured pressure deviation. Together, they ensure that the pressure at each high point does not fall below the vaporization pressure threshold throughout the valve closing process, fundamentally eliminating the triggering conditions for water hammer caused by flow interruption.

[0061] Figure 2 This is a comparison chart of the lowest pressure at each high point valve closing process between the embodiments of the present invention and the existing methods. It can be seen that the lowest pressure at each high point in the existing methods is concentrated near the lower limit of the safety pressure. The lowest pressure at each high point in the present application method is higher than that in the existing methods and exceeds the lower limit of the safety pressure. This indicates that the dynamic closing strategy of the present application achieves a more sufficient pressure safety margin at all high points.

[0062] In this way, by decomposing the lower limit of safe pressure into two parts, namely vaporization pressure and historical fluctuation amplitude, and using the relative position of the pressure deviation within the safe margin zone to drive the compensation amount, and using the half-wave width of water hammer as the threshold for the stabilization time, a real-time response to the risk of negative pressure at high points is achieved, effectively reducing the risk of negative pressure at high points.

[0063] This invention also discloses a valve control system for water hammer protection of water pipelines, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, a valve control method for water hammer protection of water pipelines according to the present invention is implemented.

[0064] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

Claims

1. A valve control method for water hammer protection of water pipelines, characterized in that, include: The pipe segment length and the time difference of pressure wave arrival between adjacent nodes of the water pipeline are obtained, and the actual pressure wave velocity is obtained based on the pipe segment length and the time difference. Obtain the pipe section length from each high point to the end valve. Using the actual pressure wave velocity and the pipe section length from each high point to the end valve, calculate the expected time when the negative pressure reflected wave arrives at the valve and the water hammer half-wave width. Using the water hammer half-wave width as a reference, define the dangerous phase window before and after the expected time. Superimpose the dangerous phase windows of all high points on the time axis to form a reflected wave time sequence map. Based on the reflected wave time sequence spectrum, the valve closing rate is differentiated and assigned values ​​for each time period during the entire valve closing process to obtain a dynamic closing curve; During the execution of the dynamic closing curve, the real-time pressure values ​​of each high-point sensor are read. In response to the real-time pressure value being lower than the lower limit of the safe pressure, a return-opening control signal is sent to the valve actuator to increase the valve opening by a compensation amount based on the current value.

2. A method of valve control for water hammer protection of a water pipeline according to claim 1, characterized in that The process of obtaining the pipe segment length and the time difference of pressure wave arrival between adjacent nodes of the water pipeline, and obtaining the actual pressure wave velocity based on the pipe segment length and the time difference, includes: High-frequency pressure sensor nodes are deployed at the pump station outlet, before and after each high point, and at the end valve of the water pipeline. The collected pressure time-series data is uploaded to the control unit in real time through each sensor node; Based on the cross-correlation calculation of the pressure time sequence data of adjacent nodes by the control unit, the time difference of pressure wave arrival between the two nodes is extracted. Divide the known pipe segment length between adjacent nodes by the measured time difference to obtain the actual pressure wave velocity under the current operating conditions.

3. A method of valve control for water hammer protection of a water pipeline according to claim 1, characterized in that The calculation of the expected arrival time of the negative pressure reflected wave at the valve and the water hammer half-wave width at each high point, using the actual pressure wave velocity and the pipe section length from each high point to the end valve, includes: In response to the terminal valve receiving a shut-off start signal, the start time is recorded; Based on the start-up time, the pipe length from each high point to the end valve, and the actual pressure wave velocity, calculate the expected time when the negative pressure reflected wave at each high point will travel from the high point, propagate through the pipeline, and reach the valve. Divide the pipe section length from each high point to the end valve by the actual pressure wave velocity to obtain the water hammer half-wave width corresponding to each high point.

4. The method of claim 1, wherein, The process of superimposing the danger phase windows of all high points on the time axis to form a time series spectrum of reflected waves includes: Overlay all the dangerous phase windows at high points on the time axis to form a complete reflection wave time sequence map, and mark all dangerous periods that need to be avoided during the entire valve closing process in the generated reflection wave time sequence map; Since the danger phase windows of two adjacent high points overlap on the time axis, the union of the two windows is taken as the merged danger period.

5. The method of claim 1, wherein, The step of assigning differentiated values ​​to the valve closing rate in each time period of the entire valve closing process based on the reflected wave time sequence spectrum to obtain a dynamic closing curve includes: In response to the period marked as a safe time in the timing diagram, the valve is driven to operate at a high closing rate; In response to the interval marked as a dangerous phase window in the time series diagram, the valve closing rate is switched to an extremely slow mode that approaches zero, so that the valve opening remains approximately constant during this window. In response to the end of the dangerous phase window, it automatically resumes the normal shutdown rate during the safe period.

6. A method of valve control for water hammer protection of a water pipeline according to claim 1, characterized in that The step of reading the real-time pressure values ​​of each high-point sensor, in response to the real-time pressure value falling below the safe pressure lower limit, includes: Obtain the vaporization pressure and safety margin corresponding to the water temperature at this high point; When there is sufficient historical pressure sequence data, the maximum and minimum values ​​of the historical pressure sequence under normal operating conditions are obtained, and the difference between the maximum and minimum values ​​is used as the safety margin. The lower limit of the safety pressure is obtained by combining the vaporization pressure and the safety margin. The real-time pressure value is compared with the lower limit of safe pressure.

7. The method of claim 1, wherein, The step of sending a return-opening control signal to the valve actuator to increase the valve opening by a compensation amount based on the current value includes: Obtain the rated maximum angular velocity and single-step control cycle given by the valve actuator; Multiplying the rated maximum angular velocity by the single-step control cycle yields the maximum allowable change in valve opening within a single control cycle. Calculate the deviation between the lower limit of the safe pressure and the real-time pressure value; The difference between the lower limit of the safety pressure and the vaporization pressure is calculated as the total width of the safety margin band; The compensation amount is calculated based on the deviation, the total width of the safety margin band, and the maximum opening change.

8. A method of valve control for water hammer protection of a water pipeline according to claim 7, characterized in that After calculating the compensation amount based on the deviation, the total width of the safety margin band, and the maximum opening change, the method further includes: In response to the real-time pressure value falling below the vaporization pressure, an upper limit constraint is forcibly applied to the compensation amount; The compensation amount is taken as the maximum opening change amount.

9. The method of claim 1, wherein, After sending a return-opening control signal to the valve actuator and increasing the valve opening by a compensation amount based on the current value, the method further includes: The recovery trend of the pressure at this high point is continuously monitored using the sensor sampling cycle as the timer. When the real-time pressure value rises back above the lower limit of the safety pressure and remains stable for a duration not less than the half-wave width of the water hammer corresponding to the high point, it is determined that the pressure has recovered and entered a new steady state. Cancel the return-open compensation to restore the valve to execute the dynamic closing curve.

10. A valve control system for water hammer protection of a water pipeline, characterized in that include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement a valve control method for water hammer protection of a water pipeline according to any one of claims 1-9.

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