A circulating water pressure low diagnosis method

Abstract

The application discloses a circulating water pressure low diagnosis method, relates to the technical field of fluid delivery systems, and comprises the following steps: collecting a water pressure value in a circulating water pipe network in real time; when the monitored water pressure value is less than or equal to a preset first pressure threshold value, calculating a water pressure drop rate within a first preset time period before the water pressure value is lower than the first pressure threshold value; if the water pressure drop rate is greater than a normal fluctuation rate threshold value and less than a mutation rate threshold value, starting active pressurization diagnosis, controlling a pressurization station or a variable frequency water pump to pressurize the circulating water pipe network once, and monitoring a pressure response characteristic of the water pressure value after the pressurization is stopped; and judging whether a pipeline leaks or not according to the pressure response characteristic. Through active pressurization diagnosis, the application can effectively eliminate false positives caused by normal water use or working condition changes, the judgment result is more reliable, and the technical defects that passive detection methods are prone to misjudgment under complex working conditions are effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of fluid transport system technology, and in particular to a method for diagnosing low circulating water pressure. Background Technology

[0002] Circulating water systems (such as industrial cooling water and urban water supply networks) often face the problem of reduced water pressure during long-term operation. Low water pressure not only affects heat exchange efficiency or user water usage, but may also indicate potential malfunctions such as pipe leaks, equipment blockages, or decreased pump efficiency.

[0003] Traditional monitoring methods often rely on a single pressure threshold alarm, triggering an alarm when the pressure falls below a set lower limit. However, this method has a significant drawback: it cannot distinguish the true cause of low water pressure, such as whether it's a genuine system leak or a non-faulty factor like a temporary interruption of upstream water supply, normal system venting, or a surge in downstream water consumption. This "always alarm when pressure drops" approach often leads to false alarms, causing unnecessary trouble for maintenance personnel and hindering accurate problem localization. Summary of the Invention

[0004] This invention provides a method for diagnosing low circulating water pressure, aiming to solve the technical problem that traditional water pressure monitoring methods are prone to false alarms.

[0005] To achieve the above objectives, the present invention provides a method for diagnosing low circulating water pressure, comprising the following steps:

[0006] The system collects and monitors the water pressure value in the circulating water network in real time. When the monitored water pressure value is less than or equal to a preset first pressure threshold, it determines whether the decrease in water pressure value is caused by active regulation. If not, it calculates the rate of decrease in water pressure within a first preset time period before the water pressure value falls below the first pressure threshold.

[0007] The water pressure drop rate is compared with a preset normal fluctuation rate threshold and a preset sudden change rate threshold, wherein the sudden change rate threshold is greater than the normal fluctuation rate threshold.

[0008] If the rate of water pressure drop is greater than the normal fluctuation rate threshold but less than the sudden change rate threshold, then active pressurization diagnosis is initiated, which includes:

[0009] The control unit sends a command to the nearest pressurization station or variable frequency water pump to the monitoring point. The pressurization station or variable frequency water pump pressurizes the circulating water network once. The pressurization stops after the pressurization time reaches a second preset time. The control unit monitors the pressure response characteristics of the water pressure value after the pressurization stops and determines whether the pipeline has leaked based on the pressure response characteristics.

[0010] This invention initiates active diagnosis based on the rate of water pressure drop. By applying active pressure into the pipeline and monitoring the pipeline's pressure response characteristics (such as whether the pressure can be maintained and the pressure recovery speed), it can effectively eliminate false alarms caused by normal water use or changes in operating conditions, further verify the pipeline's sealing integrity, and make the judgment results more reliable. It effectively overcomes the technical defects of passive detection methods that are prone to misjudgment under complex operating conditions.

[0011] Preferably, the judgment rule for determining whether a pipeline leak has occurred based on the pressure response characteristics includes:

[0012] The system checks whether the water pressure value is greater than or equal to the preset pressurization target value. If not, it diagnoses "pipeline leakage" and triggers a leak alarm.

[0013] If so, then check whether the pressure drop value of the water pressure value within the third preset time after the pressurization is stopped is greater than or equal to the preset pressure drop threshold.

[0014] If so, the diagnosis is "a leak has occurred in the pipeline network," and a leak alarm is triggered.

[0015] If not, the diagnosis is "normal operating condition fluctuation".

[0016] During the active pressurization diagnostic process, by monitoring and analyzing the pressure increase and pressure drop, it is possible to accurately distinguish between leakage and normal operating condition fluctuations, which significantly improves the reliability of leakage diagnosis and further reduces the probability of misjudgment.

[0017] Preferably, if the rate of decrease in water pressure is less than or equal to the normal fluctuation rate threshold, the water pressure value in the circulating water network continues to be monitored.

[0018] If the water pressure continues to drop to less than or equal to the set second pressure threshold, or if the water pressure fails to rise back to above the first pressure threshold after a fourth preset time, it will be diagnosed as "pipeline leakage" and a leak alarm will be triggered.

[0019] When the rate of water pressure drop is within the normal fluctuation range, diagnosis is temporarily suspended to avoid frequent triggering of diagnosis due to minor fluctuations, which would waste resources. At the same time, monitoring continues to be maintained to see if the water pressure value will drop further to the second pressure threshold or fail to recover to above the first pressure threshold for an extended period of time, in order to identify potential slow leaks or continuous leaks. This effectively compensates for the lack of sensitivity of single rate judgment in slow leak scenarios, achieving a balance between early warning and resistance to normal fluctuation interference, and further reducing the risk of missed and false alarms.

[0020] Preferably, if the rate of water pressure drop is greater than or equal to the threshold of the sudden change rate, it is diagnosed as "pipe burst or serious leak" and an emergency alarm is triggered.

[0021] Rapid loss of water pressure in the pipeline network is a typical characteristic of pipe bursts or serious leaks. This system provides a clear diagnosis for this extreme situation and triggers emergency alarms, ensuring a rapid response to serious leaks or pipe bursts. Simultaneously, it implements tiered responses for normal fluctuations, slow leaks, serious leaks, and storage, facilitating precise decision-making.

[0022] Preferably, the method for determining whether the decrease in water pressure is caused by active regulation includes:

[0023] Obtain the operating status parameters of the equipment in the circulating water network. Based on the operating status parameters, determine whether the decrease in water pressure is caused by the active control of the equipment in the circulating water network. If so, diagnose it as "planned water pressure reduction" and continue to monitor the water pressure in the circulating water network, without calculating the rate of water pressure decrease.

[0024] By acquiring the operating status parameters of equipment in the circulating water network, pressure changes caused by normal operation can be accurately eliminated, avoiding misjudging planned operations as pipe bursts or leaks, significantly reducing the system's false alarm rate, and saving computing resources.

[0025] Preferably, the operating status parameters include at least one of the following:

[0026] The start / stop status of the water pump;

[0027] The operating frequency of the water pump;

[0028] The operating current of the water pump;

[0029] The valve's open / closed status;

[0030] The degree of valve opening.

[0031] These parameters are all measurable parameters that are routinely collected in the circulating water system. They are easy to obtain and have clear physical meanings, and can comprehensively cover common active control scenarios, ensuring the accuracy of active control judgments.

[0032] Preferably, the diagnostic results are output after each diagnosis is completed.

[0033] This allows the system or operators to clearly understand the diagnostic conclusions, facilitating subsequent appropriate actions.

[0034] Preferably, after the emergency alarm or the leakage alarm is triggered, alarm information is generated, and the alarm information includes at least one of the following:

[0035] Monitoring point location, minimum water pressure value, and water pressure drop rate.

[0036] This information helps maintenance personnel quickly locate the fault, assess the severity of the leak, and determine the likelihood of a pipe burst, thereby enabling them to develop precise emergency repair plans.

[0037] Preferably, if the diagnosis is "normal operating condition fluctuation", then the pressure fluctuation is recorded as a pressure fluctuation event.

[0038] The resulting historical data can be used for subsequent analysis, optimization, and evaluation, providing data support for the refinement and maintenance of circulating water pipe networks.

[0039] Preferably, the pressure fluctuation event includes at least one of the following:

[0040] The timing of this pressure fluctuation;

[0041] The lowest water pressure value during this pressure fluctuation;

[0042] The rate of decrease in water pressure during this pressure fluctuation;

[0043] The location of the monitoring point where this pressure fluctuation occurred.

[0044] This event information facilitates the analysis of patterns in pipeline pressure changes, provides data support for predicting and identifying abnormal and normal fluctuations, and enables the diagnostic system to continuously optimize. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0046] Figure 1 This is a flowchart of a method according to an embodiment of the present invention. Detailed Implementation

[0047] 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 embodiments of the present invention, and not all embodiments. 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.

[0048] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] refer to Figure 1 In some embodiments, the method for diagnosing low circulating water pressure includes the following steps:

[0050] Real-time monitoring of water pressure in the circulating water network can be achieved, for example, by using pressure transmitters installed at key nodes in the network (such as pump station outlets, main pipeline branch points, and end-user terminals). It should be noted that one or more monitoring points can be set.

[0051] The system determines whether the monitored water pressure value is less than or equal to a preset first pressure threshold. This first pressure threshold is lower than the baseline pressure value during normal system operation. For example, the baseline pressure value is 0.4 MPa, and the first pressure threshold is set to 0.3 MPa. It should be noted that the first pressure threshold is the initial condition for triggering the low water pressure diagnostic process, while the baseline pressure value typically refers to the design pressure during normal system operation. The difference between the first pressure threshold and the baseline pressure value directly determines the sensitivity of the diagnostic system to pressure drop events. The smaller the difference, the more sensitive the response to pressure drop, enabling the detection of early slow leaks. However, the false alarm rate caused by normal pressure fluctuations will also increase accordingly. This high-sensitivity setting is suitable for situations where leaks are extremely sensitive, and even minor leaks can lead to serious consequences. Conversely, the larger the difference, the lower the sensitivity to pressure drop, filtering out a large number of normal pressure fluctuations, and the false alarm rate will decrease accordingly. This low-sensitivity setting is suitable for systems with frequent pressure fluctuations and a certain range of pressure variation allowed. In summary, the setting of the first pressure threshold is the result of designers weighing sensitivity and false alarm rate based on pipeline characteristics, historical pipeline operating data, and safety levels.

[0052] It should be noted that the specific values ​​of the benchmark pressure and the first pressure threshold are usually different for different monitoring points. Generally, the closer to the upstream position of the pipeline, the larger the specific value, and the closer to the downstream position of the pipeline, the smaller the specific value. However, in actual projects, if there are intermediate booster pump stations, elevated water tanks, or significant elevation changes, this trend may be locally adjusted. Those skilled in the art can assign independent values ​​to each monitoring point based on hydraulic calculation results. Preferably, in this embodiment, when there are multiple monitoring points, benchmark pressure and first pressure thresholds are independently set for different monitoring points. Each monitoring point independently starts the diagnostic process according to its corresponding benchmark pressure and first pressure threshold, and the diagnostic results of each monitoring point are uniformly managed by the control system.

[0053] When the monitored water pressure value is less than or equal to a preset first pressure threshold, it is determined whether the water pressure drop is caused by active control. For example, active control includes, but is not limited to, the active shutdown of the water pump, the active reduction of the frequency of the variable frequency water pump, the active closure or reduction of the opening of the valve, and the active opening of the bypass valve. The methods for determining whether the pressure drop is caused by active control include, but are not limited to, obtaining equipment operating status parameters, receiving active control notifications, and manual confirmation.

[0054] If the assessment determines that the pressure drop is caused by active control, then subsequent diagnostic steps will not be initiated.

[0055] If, after assessment, the pressure drop is not caused by active control, the rate of water pressure decrease within a first preset time period before the water pressure value falls below the first pressure threshold is calculated. The rate of water pressure decrease is compared with a preset normal fluctuation rate threshold and a preset abrupt change rate threshold, wherein the abrupt change rate threshold is greater than the normal fluctuation rate threshold.

[0056] If the rate of water pressure drop is greater than the normal fluctuation rate threshold but less than the sudden change rate threshold, active pressurization diagnosis is initiated. Active pressurization diagnosis includes:

[0057] The control unit sends a command to the nearest pressurization station or variable frequency water pump to the monitoring point. The pressurization station or variable frequency water pump pressurizes the circulating water network once, and stops pressurizing after the pressurization time reaches the second preset time. The control unit monitors the pressure response characteristics of the water pressure value after the pressurization stops, and judges whether the pipeline has leaked based on the pressure response characteristics.

[0058] For example, the reference pressure value of a certain monitoring point is 0.4 MPa, the first pressure threshold is set to 0.3 MPa, the first preset duration is 5 seconds, the normal fluctuation rate threshold is 0.01 MPa / s, the sudden change rate threshold is 0.02 MPa / s, and the second preset duration is 5 minutes. When the monitoring point detects that the water pressure in the pipeline has dropped to 0.3 MPa, the water pressure value of 0.36 MPa from 5 seconds ago is retrieved. The calculated water pressure drop rate is 0.012 MPa / s. The water pressure drop rate is greater than the normal fluctuation rate threshold of 0.01 MPa / s and less than the sudden change rate threshold of 0.02 MPa / s, so active pressurization diagnosis is initiated. After pressurization stops, monitor the pressure response characteristics. If the water pressure cannot be effectively increased during pressurization, or if the water pressure rises significantly during pressurization but drops rapidly after pressurization stops, it indicates a leak in the pipeline. Conversely, if the water pressure can be effectively increased during pressurization and stabilizes after pressurization stops, it indicates a low probability of a leak in the pipeline, and the large pressure drop is likely due to a large amount of water used in a short period of time.

[0059] It should be noted that the pressurization equipment closest to the monitoring point can be determined through a pre-established hydraulic topology table, rather than simply by geographical distance. For example, the pressurization equipment can be a variable frequency water pump, a pipeline booster pump, or a booster pump station.

[0060] In some embodiments, the judgment rules for determining whether a pipeline has leaked based on pressure response characteristics include:

[0061] The system checks whether the water pressure value is greater than or equal to a preset pressurization target value. Optionally, this target value can be the baseline pressure value during normal system operation (e.g., 0.4 MPa), or the water pressure value at the start of pressurization plus a preset increment (e.g., +0.1 MPa). If the water pressure value after pressurization is less than the pressurization target value, it is diagnosed as "pipeline leakage" and a leak alarm is triggered. If the water pressure value after pressurization is greater than or equal to the pressurization target value, it checks whether the pressure drop value within a third preset time period after pressurization stops is greater than or equal to a preset pressure drop threshold. If yes, it is diagnosed as "pipeline leakage" and a leak alarm is triggered; otherwise, it is diagnosed as "normal operating condition fluctuation." It should be noted that the third preset time period is calculated from the moment pressurization stops.

[0062] For example, the target pressurization value is 0.4 MPa, the third preset duration is 5 minutes, and the preset pressure drop threshold is 0.05 MPa. For example, if the water pressure is 0.35 MPa when pressurization stops, which is less than the target pressurization value, then it is diagnosed as "pipeline leakage" and a leak alarm is triggered. Alternatively, if the water pressure is 0.4 MPa when pressurization stops, and the water pressure drops by 0.32 MPa 5 minutes after pressurization stops, the pressure drop is 0.08 MPa, which is greater than the preset pressure drop threshold, then it is diagnosed as "pipeline leakage" and a leak alarm is triggered. For example, if the water pressure is 0.4 MPa when pressurization stops, and the water pressure drops by 0.38 MPa 5 minutes after pressurization stops, the pressure drop is 0.02 MPa, which is less than the preset pressure drop threshold, then it is diagnosed as "normal operating condition fluctuation".

[0063] In some embodiments, if the rate of water pressure drop is less than or equal to the normal fluctuation rate threshold, the water pressure value in the circulating water network continues to be monitored; if the water pressure value continues to drop to less than or equal to the set second pressure threshold, or if the water pressure value still does not rise back to above the first pressure threshold after a fourth preset time, it is diagnosed as "leaking in the network" and a leak alarm is triggered.

[0064] For example, the baseline pressure at a certain monitoring point is 0.4 MPa, the first pressure threshold is set to 0.3 MPa, the first preset time is 5 seconds, and the normal fluctuation rate threshold is 0.01 MPa / s. When the monitoring point detects a drop in water pressure in the pipeline to 0.3 MPa, the water pressure value from 5 seconds ago is retrieved as 0.34 MPa. The calculated water pressure drop rate is 0.008 MPa / s, which is less than the normal fluctuation threshold of 0.01 MPa / s. Therefore, no diagnosis or alarm is triggered at this time. However, if there is a slow leak in the pipeline... A short-term drop in water pressure may be below the normal fluctuation rate threshold, but if left unchecked, the pressure will gradually decrease or fail to recover automatically, or even worsen into a more serious leak or pipe burst. Therefore, it is necessary to continue monitoring the water pressure in the circulating water network. If the water pressure continues to drop to less than or equal to the set second pressure threshold (e.g., 0.2 MPa), or if the water pressure does not rise back to above the first pressure threshold after a fourth preset time (e.g., 10 minutes), it is diagnosed as "leaking in the network" and a leak alarm is triggered, requiring maintenance to be arranged.

[0065] In some embodiments, if the rate of water pressure drop is greater than or equal to the rate of change threshold, it is diagnosed as "pipe burst or serious leak" and an emergency alarm is triggered.

[0066] For example, the reference pressure value of a certain monitoring point is 0.4 MPa, the first pressure threshold is set to 0.3 MPa, the first preset duration is 5 seconds, and the change rate threshold is 0.02 MPa / s. When the monitoring point detects that the water pressure in the pipeline has dropped to 0.3 MPa, the water pressure value of 0.42 MPa from 5 seconds ago is retrieved. The calculated water pressure drop rate is 0.024 MPa / s. Since the water pressure drop rate is greater than the change rate threshold of 0.02 MPa / s, it is diagnosed as "pipe burst or serious leak" and an emergency alarm is triggered.

[0067] For example, emergency alarms and leakage alarms may take the form of, but are not limited to, audible and visual alarms, human-machine interface pop-up alarms, SMS alarms, and application push alarms.

[0068] It should be noted that the specific value of the first preset duration should be set according to the following principles: because a pipe burst will cause a sharp drop in pressure, and a significant pressure drop can be formed in a short time, if a rapid alarm is expected for serious leaks or pipe burst accidents, the first preset duration should be set to a smaller value; because the pressure drop of slow leakage is small in a short time and is easily drowned out by normal fluctuations or detection noise, if a more accurate detection of early slow leaks is expected, the first preset duration should be set to a larger value. The setting of the first preset duration is a result of balancing the rapid alarm for serious leaks or pipe burst accidents with the accurate detection of early slow leaks.

[0069] More preferably, two sets of specific values ​​can be set for the first preset duration. The two sets of values ​​are calculated independently. The set with the smaller value is used to diagnose serious leaks or pipe bursts, and the set with the larger value is used to diagnose slow leaks. For example, 2 seconds and 8 seconds can be set at the same time. If the water pressure drop rate within 2 seconds is greater than or equal to the sudden change rate threshold, it is diagnosed as "pipe burst or serious leak" and an emergency alarm is triggered. If the water pressure drop rate within 8 seconds is greater than or equal to the normal fluctuation rate threshold, it is diagnosed as "pipeline leakage" and a leak alarm is triggered. This approach balances rapid alarm for serious leaks or pipe bursts with accurate detection of early slow leaks.

[0070] In some embodiments, determining whether a decrease in water pressure is caused by active regulation includes: acquiring operating status parameters of equipment in the circulating water network, exemplarily, these parameters are uploaded to the control unit via a fieldbus or wireless network; based on the operating status parameters, determining whether the decrease in water pressure is caused by active regulation of equipment in the circulating water network; if so, diagnosing it as "planned water pressure reduction", and continuing to monitor the water pressure in the circulating water network, without calculating the rate of water pressure decrease or triggering subsequent rate comparisons and active pressurization diagnoses.

[0071] In some embodiments, the running status parameters include at least one of the following:

[0072] The start / stop status of the water pump;

[0073] The operating frequency of the water pump;

[0074] The operating current of the water pump;

[0075] The valve's open / closed status;

[0076] The degree of valve opening.

[0077] If the water pump is detected to be stopped, or the water pump operating frequency or current decreases at a set rate, or the valve is closed, or the valve opening decreases as set, then the decrease in water pressure can be determined to be caused by active control. Optionally, this judgment can be made based on one operating status parameter, or a comprehensive judgment can be made based on multiple operating status parameters; the latter improves the reliability of the judgment. It should be noted that the operating status parameters used for judgment are not limited to the above-mentioned types, and can also include the inverter's output frequency, output power, and preset equipment action commands in the control system.

[0078] In some embodiments, after each diagnosis is completed, diagnostic results such as "pipe burst or serious leak," "pipeline leakage," "normal operating condition fluctuation," and "planned water pressure reduction" are output. Exemplarily, the output can be displayed as text or icons on a local human-machine interface, or a diagnostic log can be generated and recorded in a database. It should be noted that the output of diagnostic results is independent of whether an alarm is triggered; even if the diagnosis is "normal operating condition fluctuation" or "planned water pressure reduction," it should still be output for subsequent statistical analysis.

[0079] Preferably, the diagnostic results are sent to a remote terminal. For example, the remote terminal could be a monitoring computer located in the central control room, a mobile terminal for management personnel, or a third-party cloud platform. This enables real-time remote transmission of diagnostic information, allowing relevant personnel to obtain the pipeline network's operational status immediately, shortening fault response time, and facilitating centralized management and rapid decision-making.

[0080] In some embodiments, after an emergency alarm or leakage alarm is triggered, alarm information is generated, which includes at least one of the following: monitoring point location, minimum water pressure value, and water pressure drop rate. It should be noted that the minimum water pressure value refers to the valley value recorded during the pressure drop process, not the current real-time value; the water pressure drop rate is the rate of water pressure drop within a first preset time period before the water pressure value falls below a first pressure threshold. The alarm information is output to a local human-machine interface or an alarm log is generated and recorded in a database.

[0081] Preferably, the alarm information is sent to a remote terminal. For example, the remote terminal may be a monitoring computer located in the central control room, a mobile terminal of the administrator, or a third-party cloud platform. This enables automatic alarm and remote notification in unattended situations, allowing for immediate action to be taken in response to faults.

[0082] In some embodiments, if a "normal operating condition fluctuation" is diagnosed, the pressure fluctuation is recorded as a pressure fluctuation event. Exemplarily, this pressure fluctuation record is stored in a local historical database or a cloud database. Exemplarily, a pressure fluctuation event includes at least one of the following:

[0083] The timing of this pressure fluctuation;

[0084] The lowest water pressure value during this pressure fluctuation;

[0085] The rate of decrease in water pressure during this pressure fluctuation;

[0086] The location of the monitoring point where this pressure fluctuation occurred.

[0087] This information can be used to analyze the patterns of pressure changes in the pipeline network, providing data support for predicting and identifying abnormal and normal fluctuations, providing data support for the fine-tuning and maintenance of the circulating water pipeline network, and enabling the diagnostic system to have continuous optimization capabilities.

[0088] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0089] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for diagnosing low circulating water pressure, characterized in that, Includes the following steps: The system collects and monitors the water pressure value in the circulating water network in real time. When the monitored water pressure value is less than or equal to a preset first pressure threshold, it determines whether the decrease in water pressure value is caused by active regulation. If not, it calculates the rate of decrease in water pressure within a first preset time period before the water pressure value falls below the first pressure threshold. The water pressure drop rate is compared with a preset normal fluctuation rate threshold and a preset sudden change rate threshold, wherein the sudden change rate threshold is greater than the normal fluctuation rate threshold. If the rate of water pressure drop is greater than the normal fluctuation rate threshold but less than the sudden change rate threshold, then active pressurization diagnosis is initiated, which includes: The control unit sends a command to the nearest pressurization station or variable frequency water pump to the monitoring point. The pressurization station or variable frequency water pump pressurizes the circulating water network once. The pressurization stops after the pressurization time reaches a second preset time. The control unit monitors the pressure response characteristics of the water pressure value after the pressurization stops and determines whether the pipeline has leaked based on the pressure response characteristics.

2. The method for diagnosing low circulating water pressure according to claim 1, characterized in that, The judgment rules for determining whether a pipeline has leaked based on the pressure response characteristics include: The system checks whether the water pressure value is greater than or equal to the preset pressurization target value. If not, it diagnoses "pipeline leakage" and triggers a leak alarm. If so, then check whether the pressure drop value of the water pressure value within the third preset time after the pressurization is stopped is greater than or equal to the preset pressure drop threshold. If so, the diagnosis is "a leak has occurred in the pipeline network," and a leak alarm is triggered. If not, the diagnosis is "normal operating condition fluctuation".

3. The method for diagnosing low circulating water pressure according to claim 2, characterized in that, If the rate of decrease in water pressure is less than or equal to the normal fluctuation rate threshold, then the water pressure value in the circulating water network will continue to be monitored. If the water pressure continues to drop to less than or equal to the set second pressure threshold, or if the water pressure fails to rise back to above the first pressure threshold after a fourth preset time, it will be diagnosed as "pipeline leakage" and a leak alarm will be triggered.

4. The method for diagnosing low circulating water pressure according to claim 3, characterized in that, If the rate of water pressure drop is greater than or equal to the threshold of the sudden change rate, it is diagnosed as "pipe burst or serious leak" and an emergency alarm is triggered.

5. The method for diagnosing low circulating water pressure according to claim 1, characterized in that, The methods for determining whether the decrease in water pressure is caused by active regulation include: Obtain the operating status parameters of the equipment in the circulating water network. Based on the operating status parameters, determine whether the decrease in water pressure is caused by the active control of the equipment in the circulating water network. If so, diagnose it as "planned water pressure reduction" and continue to monitor the water pressure in the circulating water network, without calculating the rate of water pressure decrease.

6. The method for diagnosing low circulating water pressure according to claim 5, characterized in that, The operating status parameters include at least one of the following: The start / stop status of the water pump; The operating frequency of the water pump; The operating current of the water pump; The valve's open / closed status; The degree of valve opening.

7. The method for diagnosing low circulating water pressure according to any one of claims 1-6, characterized in that, After each diagnosis is completed, the diagnosis result is output.

8. The method for diagnosing low circulating water pressure according to claim 4, characterized in that, Upon triggering the emergency alarm or the leakage alarm, alarm information is generated, which includes at least one of the following: Monitoring point location, minimum water pressure value, and water pressure drop rate.

9. The method for diagnosing low circulating water pressure according to claim 2, characterized in that, If the diagnosis is "normal operating condition fluctuation", then the pressure fluctuation will be recorded as a pressure fluctuation event.

10. The method for diagnosing low circulating water pressure according to claim 9, characterized in that, The pressure fluctuation event includes at least one of the following: The timing of this pressure fluctuation; The lowest water pressure value during this pressure fluctuation; The rate of decrease in water pressure during this pressure fluctuation; The location of the monitoring point where this pressure fluctuation occurred.

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