Energy-saving method of box type non-negative pressure equipment based on risk grading dynamic regulation

Abstract

The present application relates to the field of electric digital data processing, and particularly relates to a kind of energy-saving method of box type non-negative pressure equipment based on risk grading dynamic regulation, method includes: obtaining box type non-negative pressure cascade equipment operating parameter and preprocessing constructs system state vector;According to the difference of equipment topology water supply characteristics, determine the buffer capacity coefficient, combine the disturbance characteristic index of flow rate change rate, coupling quantitative instantaneous risk value of real-time load rate, combined with disturbance cumulative effect, calculate the overall disturbance index of cascade system;Based on current load coefficient and corrected pressure, calculate the equipment health state index, and the two are coupled to construct comprehensive risk index;Preset multistage threshold value determines risk level, complete equipment energy-saving processing.The present application differentiates to determine the buffer capacity coefficient, quantifies the cumulative risk of hydraulic disturbance, couples to construct comprehensive risk index and divides four-level operation mode to implement differential regulation, realizes hydraulic disturbance real-time response and dynamic balance of safe energy saving.

Description

Technical Field

[0001] This invention relates to the field of electronic digital data processing. In particular, it relates to an energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control. Background Technology

[0002] Risk analysis is the core support for the water supply control of box-type negative pressure cascade equipment. As key equipment for zoned water supply in high-rise buildings, the operating status of this type of equipment is directly related to energy consumption, cost, and water supply continuity. Risk analysis can accurately identify potential threats such as equipment aging, sudden changes in water load, and the propagation of cascaded disturbances, providing a scientific basis for the formulation of control strategies. It is also key to responding to energy conservation and emission reduction policies and balancing water supply security and operational economy, effectively avoiding water supply interruptions or energy waste.

[0003] Data processing is the foundation of risk analysis and precise equipment adjustment; its quality directly determines the accuracy of risk assessment and the effectiveness of control strategies. The operation of box-type negative pressure cascade equipment involves multiple parameters such as water level, pressure, flow rate, and current. Through real-time data acquisition, anomaly correction, noise filtering, and standardization, interference factors can be eliminated, and a reliable system state vector can be constructed. This provides high-quality data support for subsequent disturbance identification and risk assessment, and is the core guarantee for achieving controllable risks and effective energy conservation.

[0004] Existing energy-saving control technologies for box-type negative pressure cascade equipment have significant limitations: fixed-parameter optimization control cannot adapt to changes in system characteristics caused by equipment aging; predictive control based on historical data is prone to model mismatch under sudden operating conditions such as fire-fighting water supply, making it difficult to respond to instantaneous load changes; single-point disturbance detection ignores the bidirectional propagation characteristics of disturbances in cascaded systems and fails to distinguish the risk weights of different disturbances. More importantly, existing technologies treat safety and energy saving as mutually exclusive goals, lacking dynamic control mechanisms and failing to achieve an optimal balance under different risk scenarios, thus limiting the reliability and economy of equipment operation. Summary of the Invention

[0005] To address the limitations of existing energy-saving control technologies for box-type negative pressure cascade equipment, such as adaptability, sudden response, and disturbance identification, and the failure to balance safety and energy saving, which restricts the reliability and economy of equipment operation, this invention provides solutions in the following aspects.

[0006] An energy-saving method for box-type negative pressure-free cascade equipment based on risk-level dynamic control includes: acquiring and preprocessing the operating parameter data of the box-type negative pressure-free cascade equipment to construct a system state vector; based on the system state vector and the topological water supply characteristics of the box-type negative pressure-free cascade equipment, differentially determining the buffer capacity coefficient of each level of equipment tank; using the product of the buffer capacity coefficient and the absolute value of the flow rate change as the disturbance characteristic index of each level of equipment tank; coupling the real-time load rate and disturbance characteristic index of each level of equipment tank to quantify the instantaneous risk value of each level of equipment tank; calculating the overall disturbance index of the cascade system based on the instantaneous risk value of each level of equipment tank and the cumulative effect of the disturbance characteristic index within a preset time window; calculating the health status index of each level of equipment tank based on the current load coefficient and corrected pressure of the single-stage equipment in the cascade system; multiplying the overall system disturbance index with the equipment health status index to construct a comprehensive risk index of the current feasible energy-saving level of the cascade system; preset multi-level risk classification thresholds and judging based on the comprehensive risk index to determine the current risk level of the box-type negative pressure-free equipment, thus completing the energy-saving treatment of the box-type negative pressure-free equipment.

[0007] Preferably, the step of obtaining the buffer capacity coefficient includes: In response to the case that the box-type negative pressure-free cascade equipment is the primary equipment water tank, the ratio of the current water level of the primary equipment water tank to the maximum water level of the corresponding water tank is used as the relative water level coefficient to reflect the buffering capacity coefficient of the primary equipment water tank. Any water tank other than the primary equipment tank is used as the water tank to be analyzed. The ratio of the real-time outlet pressure of the water tank preceding the water tank to be analyzed to the maximum outlet pressure of the water tank preceding the water tank within a preset time period is used as the relative pressure coefficient to reflect the buffering capacity coefficient of the water tank to be analyzed.

[0008] Preferably, the calculation method of the disturbance characteristic index includes: Calculate the flow rate change rate of each water tank at the level to be analyzed and take the absolute value. Multiply the absolute value by the buffer capacity coefficient to obtain the disturbance characteristic index of the water tank at the level to be analyzed.

[0009] Preferably, the calculation method for the overall system disturbance index includes: The cumulative energy of the disturbance is characterized by the integral value of the disturbance characteristic index within a preset time window calculated by definite integral. The average disturbance intensity is obtained by dividing the integral value by the length of the time window, and then the disturbance cumulative effect factor is obtained by negative exponential transformation and normalization. Multiply the instantaneous risk value of each equipment tank by the corresponding disturbance cumulative effect factor to obtain the fusion risk of each equipment tank. Take the maximum value of the fusion risk of each equipment tank to obtain the overall disturbance index of the cascaded system.

[0010] Preferably, the health status index of water tanks at each level of equipment is calculated, including: For each stage of equipment water tank, the ratio of real-time operating current to rated current is calculated to obtain the current load factor of the single-stage equipment. The maximum value of real-time outlet pressure and lower pressure threshold is calculated as the correction pressure, and the ratio of rated pressure to correction pressure is used as the pressure correction factor of the single-stage equipment water tank. The product of the current load factor and pressure correction factor of the single-stage equipment water tank is used as the health degradation value of the single-stage equipment water tank. The maximum value of the health degradation value of each stage of equipment water tank is taken to obtain the equipment health status index.

[0011] Preferably, the lower pressure threshold is the product of a preset minimum coefficient and the rated pressure of the corresponding equipment.

[0012] Preferably, the risk level of the box-type negative pressure-free equipment is determined based on comprehensive risk indicators, including: In response to the comprehensive risk index being less than the preset threshold If the box-type negative pressure-free equipment is in super-optimal mode, it will respond when the comprehensive risk index is greater than or equal to the preset threshold. And less than the preset threshold If the box-type negative pressure-free equipment is in optimized mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. And less than the preset threshold If the box-type negative pressure-free equipment is in safe mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. If so, the box-type negative pressure-free equipment is in protection mode.

[0013] Preferably, the preprocessing step includes: An anomaly detection method based on the safe operating boundary of the equipment is adopted to identify and remove operating parameter data that exceeds the reasonable range. Linear interpolation is used to fill in the missing time series data. Data standardization maps the parameters of each dimension to the [0,1] interval to eliminate the difference in units.

[0014] The present invention has the following effects: 1. This invention determines the buffer capacity coefficient by differentiating the topological water supply characteristics of box-type negative pressure cascade equipment, constructs a disturbance characteristic index by combining the flow change rate, and quantifies the cumulative disturbance effect within a preset time window through definite integral and negative exponential transformation, thereby achieving real-time and accurate identification of hydraulic disturbances and quantification of cumulative risks. At the same time, based on the maximum value of the fused risk, the overall disturbance index of the cascade system is obtained, which can quickly capture the most dangerous disturbance risk points in the cascade equipment, greatly improve the system's response speed to sudden water usage fluctuations, abnormal pipeline pressure, and other situations, and ensure water supply stability.

[0015] 2. This invention constructs a comprehensive risk index by coupling the overall system disturbance index and the equipment health status index. Based on multi-level thresholds, it divides the system into four operating modes: super-optimal, optimized, safe, and protective. Differentiated energy-saving and safety control strategies are configured for different modes. This maximizes the energy-saving potential in low-risk scenarios and prioritizes the safety of equipment and water supply in high-risk scenarios, achieving dynamic adaptation between safety priority and energy-saving efficiency, and taking into account both the reliability and economy of equipment operation. Attached Figure Description

[0016] Figure 1 This is a flowchart of steps S1-S4 in an energy-saving method for a box-type negative pressure-free equipment based on risk classification and dynamic control according to an embodiment of the present invention. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0018] Reference Figure 1 An energy-saving method for box-type negative pressure-free equipment based on risk classification and dynamic control includes steps S1-S4, as detailed below: S1: Obtain the operating parameter data of the box-type negative pressure cascade equipment, perform preprocessing, and construct the system state vector.

[0019] The water level of the primary equipment water tank in the box-type negative pressure cascade equipment is collected in real time at a sampling frequency of 1Hz using a high-precision pressure level sensor, an industrial-grade pressure transmitter, an ultrasonic flow meter, and a Hall current sensor. Water tank outlet pressure at each level of equipment Water output from user terminals of water tanks at all levels of equipment and the operating current of water tanks at all levels of equipment ,in , This represents the total number of stages in the cascaded system. The preprocessing steps include: employing an anomaly detection method based on the safe operating boundary range of the equipment; when a parameter exceeds this range, replacing the abnormal value with the valid value from the previous moment and triggering a protection mechanism; and using a sliding window size of 3, corresponding to 3 sampling periods, a sliding window mid-range filtering algorithm is applied to each parameter sequence. Filtering is performed to eliminate random noise; based on the physical limits of the equipment, min-max normalization is applied to the acquired parameters of different dimensions; timing is unified, aligning all parameters at the same timestamp to construct the system state vector. .

[0020] In box-type negative pressure cascade equipment, traditional disturbance detection methods rely on flow or pressure thresholds at a single device point, which has the following drawbacks: First, they cannot identify the propagation path and impact range of disturbances in the cascade system, especially whether the disturbance is propagated from the water tank of the first-stage device to the subsequent stage or from the final stage device to the previous stage; second, they fail to distinguish whether the dedicated water tank of the first-stage device has buffering capacity and the operating characteristics of other stages of pure frequency conversion water supply, resulting in a lack of differentiated control strategies and an inability to adapt to the operating characteristics of different levels of equipment.

[0021] Therefore, in order to accurately identify the disturbance propagation mechanism, the spatiotemporal characteristics of disturbance propagation in the cascaded system are analyzed by examining the response correlation of water tanks at each level under disturbance, thereby accurately identifying the disturbance propagation mechanism. The specific steps are as follows: S2: Based on the system state vector and the topological water supply characteristics of the box-type negative pressure cascade equipment, the buffer capacity coefficient of each equipment tank is determined differently. The product of the buffer capacity coefficient and the absolute value of the flow rate change rate is used as the disturbance characteristic index of each equipment tank. The real-time load rate and disturbance characteristic index of each equipment tank are coupled and calculated to quantify the instantaneous risk value of each equipment tank. Based on the instantaneous risk value of each equipment tank and the cumulative effect of the disturbance characteristic index within the preset time window, the overall disturbance index of the cascade system is calculated.

[0022] In response to the case where the box-type negative pressure cascade equipment is the primary equipment tank, the ratio of the current water level of the primary equipment tank to the maximum water level of the corresponding tank is used as the relative water level coefficient to reflect the buffering capacity coefficient of the primary equipment tank. Other primary equipment tanks are used as the tanks to be analyzed, and the ratio of the real-time outlet pressure of the tank preceding the tank to the maximum outlet pressure of the tank preceding the tank within a preset time period is used as the relative pressure coefficient to reflect the buffering capacity coefficient of the other equipment tanks.

[0023] Specifically, the buffer capacity coefficient satisfies the following relationship: ; In the formula, Indicates the first The water tank of the first-level equipment is in the first stage The buffering capacity coefficient at any given moment; This indicates that the primary equipment water tank is in the first stage. The water level at that moment; This indicates the maximum water level in the primary equipment's water tank; This indicates that the water tank of the previous stage equipment is in the [stage name missing]. The water pressure at any given time; This indicates the maximum outlet water pressure of the upstream equipment's water tank within a preset time period, taken from the past... Day The maximum outlet pressure of the water tank of the first-stage equipment is used as the reference pressure to reflect the rated water supply pressure level of the water tank of the previous stage equipment.

[0024] Because the structure and function of the primary equipment water tank determine its buffering capacity, as the source equipment in a cascaded system, each primary equipment unit is equipped with its own dedicated water tank. This tank is the core energy storage and buffering component of the system, and its water level directly reflects the system's water storage capacity, determining its ability to cope with sudden water demand and resist the risks of air evacuation and overflow. It is the foundation for the water supply stability of the primary equipment water tank itself and subsequent equipment tanks at all levels. Therefore, the buffering capacity coefficient of the primary equipment water tank needs to be quantified by the ratio of the current water level to the maximum water level of the corresponding primary equipment water tank, directly relating to the availability of its core buffering resources, and thus accurately assessing the disturbance risks faced by the primary equipment water tank.

[0025] Secondary and higher-level equipment does not have an independent water tank, and its stability depends on the upstream water supply pressure: Secondary and higher-level equipment is a pure frequency conversion water supply structure without dedicated energy storage components. Its water supply stability depends entirely on the output pressure of the upstream equipment's water tank. Whether the upstream water pressure is stable and reaches the rated level directly determines whether the upstream equipment can normally adapt to water demand and resist disturbances.

[0026] Calculate the flow rate change rate of each water tank at the level to be analyzed and take the absolute value. Multiply the absolute value by the buffer capacity coefficient to obtain the disturbance characteristic index of the water tank at the level to be analyzed.

[0027] Specifically, the disturbance characteristic index satisfies the following relationship: ; In the formula, Indicates the first Level equipment in The perturbation characteristics at any given time; Indicates the first Level equipment in The water output at any given time; Indicates the first Level equipment in The rate of change of flow at any given time; Indicates the first Level equipment in The buffering capacity coefficient at any given moment.

[0028] The rate of change of flow rate characterizes the rate of change of water volume over time, and is more sensitive to the sudden changes in water demand. Taking the absolute value of the rate of change of flow rate aims to achieve a unified quantification of the threat intensity of positive disturbances (such as surges in flow rate for fire fighting) and negative disturbances (such as abnormal decreases in flow rate due to pipeline leaks), so as to avoid omissions in threat assessment due to different directions of disturbance.

[0029] Disturbance characteristic indicators are used to quantify the comprehensive disturbance risk faced by water tanks at all levels of equipment at the current moment. Their physical meaning is the intensity of flow change that the equipment can withstand under unit buffer capacity, which can accurately reflect the disturbance response pressure of the equipment under the current operating conditions.

[0030] When the disturbance characteristic index is much greater than 0, for the primary equipment water tank, it indicates that the buffer resources of the water tank are being rapidly consumed, the system is close to the instability critical point, and faces the risk of being emptied or unable to meet the subsequent water supply demand; for secondary and above equipment, it indicates that the water supply pressure of the previous equipment water tank is no longer able to adapt to the dynamic changes in the current level water demand, and the operational stability of the current level equipment is significantly threatened.

[0031] When the disturbance characteristic index approaches 0, there are two different operating conditions for the primary equipment water tank: one is that the system is in an ideal steady-state operation, with extremely stable water demand and sufficient water storage in the tank, the equipment is operating at its optimal operating point, and both energy utilization efficiency and water supply stability are at their best levels; the other is that the water level in the tank is close to empty. When the water demand approaches zero, although the change in water demand is small, the system has completely lost its buffering capacity. Even a small increase in water demand may cause the primary equipment tank to be unable to meet the water demand of its own water supply area and the water tanks of subsequent equipment levels at the same time, thus causing the system to fail in a cascade manner. For secondary and higher-level equipment, it indicates that the water demand of this level of equipment changes slowly, and the outlet water pressure provided by the water tank of the previous level equipment is stable near the rated value. The entire cascade system is in a state of load balance, and the water tanks of each level of equipment work together in the high-efficiency operating range, with the energy utilization rate reaching the highest level.

[0032] In box-type negative pressure cascade equipment, disturbance characteristic index identification can only reveal the transmission pattern of disturbances between water tanks at each level, and cannot achieve a quantitative assessment of the specific risk level faced by the system. According to the working principle of the cascade system, except for the final stage equipment, each stage equipment water tank undertakes the dual task of supplying water to users in its corresponding pressurized area and providing water supply support for the next stage equipment water tank. This means that the failure of any stage equipment water tank (especially the upstream equipment) will directly affect the water supply safety of its own water supply area and all downstream areas. The overall risk level of the system is determined by the weakest link. Therefore, accurately identifying the dynamic risk level of the weakest link is the key to ensuring the safe operation of the system.

[0033] However, traditional fixed threshold determination methods have significant drawbacks: they do not consider the differences in risk impact weights corresponding to the device topology location (the risk impact range of front-end devices is much larger than that of back-end devices), ignore the dynamic correlation between the real-time load status of devices and their disturbance tolerance (the higher the load rate, the weaker the disturbance tolerance), and lack time dimension considerations. They cannot distinguish between short-term flow fluctuations that can be buffered and absorbed by the system and continuous water usage peaks that will lead to risk accumulation, making it difficult to accurately locate the dynamic risks of the weakest link.

[0034] To accurately identify the dynamic risk level of the weakest link in the system, it is necessary to construct an overall system disturbance index. By integrating instantaneous risk intensity with the cumulative effect of historical disturbances, a quantitative indicator that can comprehensively reflect the overall vulnerability of the cascaded system is formed. The specific steps are as follows: The real-time load rate of each equipment tank is calculated separately. The disturbance characteristic index of each equipment tank is multiplied by the corresponding real-time load rate to obtain the instantaneous risk value. The cumulative energy of the disturbance within the time window is quantified by definite integral operation for each equipment tank. The cumulative energy is divided by the length of the time integration window, and the negative exponent is taken. The result of 1 minus the negative exponent is used as the disturbance cumulative effect factor.

[0035] Multiply the instantaneous risk value of each equipment tank by the corresponding disturbance cumulative effect factor to obtain the fusion risk of each equipment tank. Take the maximum value of the fusion risk of each equipment tank to obtain the overall disturbance index of the cascaded system.

[0036] Specifically, the overall system disturbance index satisfies the following relationship: ; In the formula, Indicates the overall system disturbance index; Indicates the first Level equipment in The perturbation characteristics at any given time; Indicates the first Level equipment in The water output at any given time; Indicates the first The maximum water output of the equipment within a preset time period is taken from the past. Day The maximum output of the equipment is used as the benchmark flow rate to reflect the actual capacity of the equipment during historical peak water usage periods. Indicates the length of the time integration window. The range of values ​​is To ensure that the system can effectively suppress malfunctions caused by transient disturbances and respond promptly to continuous peak water usage, this embodiment adopts... The specific details can be adjusted according to the actual application scenario; Indicates the first Level equipment at any time within the preset time window The disturbance characteristic indicators; The time variable representing the integration process, ; Represents the maximum value function. Represented by natural constant An exponential function with base 0. This represents the total number of stages in the cascaded system.

[0037] Strictly adhering to the core physical principles of risk assessment: instantaneous risk = degree of change × insufficient withstand capacity, this approach achieves precise quantification of the comprehensive risk of a single level of cascaded equipment. Among these, the disturbance characteristic index, serving as a quantitative carrier of threat intensity, comprehensively covers key information such as the rate of change and propagation characteristics of disturbances through coupled calculations of flow change rate and equipment buffer capacity. This accurately characterizes the objective threat level posed by the current disturbance to the water tanks at each level of equipment. Meanwhile, the real-time load rate, as a quantitative indicator of system vulnerability, directly reflects the real-time load status of the water tanks at each level of equipment through the ratio of real-time outflow to rated flow. A higher equipment load rate indicates a smaller remaining adjustment margin, weaker ability to resist disturbances, and higher system vulnerability.

[0038] The use of a product relationship instead of an additive relationship is fundamentally designed to adapt to the nonlinear interaction mechanism between threat intensity and system vulnerability: when the threat intensity is high but the system vulnerability is low (e.g., a sudden surge in water usage but the equipment is under light load with sufficient remaining adjustment margin), the product of the two factors is relatively low, indicating that the risk is controllable. Conversely, when the threat intensity is moderate but the system vulnerability is high (e.g., water demand changes gradually but the equipment is near full load with no room for adjustment), the product of the two factors increases significantly, indicating that the risk is at an extremely high level. This avoids the shortcomings of the additive relationship, which fails to distinguish between different risk scenarios such as high threat and low vulnerability versus low threat and high vulnerability. It ensures that the risk quantification results for individual equipment closely reflect actual operating conditions, providing accurate basic data support for subsequent overall system risk assessments.

[0039] In a box-type cascaded system without negative pressure, the water tanks at each stage form a topology where each stage provides water supply support. The water tank at the previous stage provides the core water supply foundation for the water tank at the next stage. Once the water tank at the previous stage fails, it will directly cause all downstream equipment to lose water supply, triggering a cascade failure of the system. Based on the core principle of the "barrel effect," the overall safe operation capability of the system is not determined by the average reliability of the water tanks at each stage, but is dominated by the reliability of the weakest link in the system (the equipment with the highest risk). The failure of this weak link will directly exceed the system's safety threshold, causing an interruption of the overall water supply function.

[0040] Therefore, when calculating the overall disturbance index of the cascaded system, this scheme uses the maximum value calculation instead of the average value calculation. The core purpose is to ensure that the control system always focuses on the critical equipment with the highest risk, effectively avoiding the technical defect of masking local high risks by averaging calculations. Specifically, when the fusion risk of the primary equipment tank is 0.8, and the fusion risks of the water tanks of other levels are all less than 0.3, the overall system risk should be completely dominated by the high risk value of 0.8 of the primary equipment tank. As the source water supply equipment of the cascaded system, the failure of the primary equipment tank will directly cause the collapse of the entire water supply system. If the average value calculation is used, the overall system fusion risk will be reduced to about 0.4. This result cannot truly reflect the fatal safety threat posed by the primary equipment tank, which can easily lead to misjudgment of the risk level by the control system, thereby causing serious water supply interruption accidents.

[0041] By taking the maximum value, the design precisely matches the topological safety characteristics of the box-type negative pressure cascade system, ensuring that the system risk assessment results can accurately point to the most critical safety hazards, providing a quantitative basis for subsequent control strategy switching that fits the actual safety requirements, and ensuring the reliability and continuity of system operation.

[0042] The overall system disturbance index is used to quantify the maximum spatiotemporal risk level faced by the box-type negative pressure cascade system. It is the critical risk level for the weakest equipment in the system to maintain water supply stability when it continuously withstands the current water usage disturbance intensity within a preset time window, accurately reflecting the highest risk level of the system in the time dimension and equipment topology dimension.

[0043] When the overall system disturbance index is much greater than 0, it indicates that the weakest link in the system is facing extreme disturbance risk. The water supply regulation margin of the equipment has been completely exhausted and it cannot adapt to the current disturbance intensity through its own regulation. If it is not intervened in time, it will cause equipment failure and further lead to system cascading failure. At this time, it is necessary to immediately start the emergency protection control strategy to prioritize the safety of the system water supply. When the overall system disturbance index approaches 0, it indicates that the cascaded system is operating in the optimal safe state. The water demand of the water tanks at each level changes slowly, the real-time load rate is low, and the equipment has sufficient buffer capacity and adjustment margin to effectively resist various conventional disturbances. At this time, the optimal energy-saving operation strategy can be adopted to maximize the system's energy utilization efficiency while ensuring the stability of water supply.

[0044] Although the overall system disturbance index can accurately quantify the overall risk level of the box-type negative pressure cascade system based on hydraulic parameters and provide a core basis for safety assessment, its assessment dimension has a single limitation: it only focuses on the hydraulic working condition and does not take into account the impact of the actual operating status of the equipment itself. However, the operating status of the equipment directly determines its true disturbance tolerance and energy-saving potential, which is a key factor that cannot be ignored in risk assessment and energy-saving control.

[0045] During the long-term operation of box-type negative pressure cascade equipment, the negative pressure device and booster pump of the primary equipment water tank, as well as the subsequent variable frequency water supply equipment at each stage, will all experience deterioration in operating condition due to problems such as decreased motor efficiency, wear of mechanical parts, and reduced sealing performance. Under the same hydraulic conditions, the deteriorated equipment not only has a significantly reduced energy conversion efficiency, requiring more electrical energy to maintain the established water supply capacity, but its operational reliability will also decrease accordingly, and its actual ability to withstand disturbances is far lower than that of new or well-maintained equipment. If risk assessment is based solely on the overall system disturbance index, it will fail to reflect the real safety hazards caused by equipment deterioration, and it will be difficult to accurately match the actual energy efficiency level of the equipment to formulate energy-saving strategies, which may easily lead to biased safety assessments or poor energy-saving control effects.

[0046] Parameters such as real-time operating current, cumulative operating time, and historical fault records can directly or indirectly characterize the health status of equipment: the ratio of operating current to operating pressure reflects energy conversion efficiency, cumulative operating time is related to the degree of mechanical wear, and historical fault records reflect the equipment reliability level. Based on this, to compensate for the shortcomings of a single-dimensional assessment of the overall system disturbance index and to achieve a dual and accurate assessment of hydraulic risk and equipment status, it is necessary to construct an equipment health status index, incorporating the actual operating status of the equipment into the risk assessment system. The specific steps are as follows: S3: Based on the current load coefficient and corrected pressure of the single-stage equipment in the cascade system, calculate the health status index of the water tanks of each stage of the equipment, multiply the overall system disturbance index by the equipment health status index, and construct a comprehensive risk index of the current feasible energy-saving level of the cascade system.

[0047] For each stage of the equipment's water tank, calculate the ratio of real-time operating current to rated current. This yields the current load factor for a single-stage device. In other words, this factor quantifies the proportion of the current load of the device to its rated capacity, reflecting the electrical load status of the device (the larger the ratio, the higher the electrical load and the higher the risk of energy efficiency degradation).

[0048] The maximum value between the real-time outlet pressure and the lower pressure threshold is calculated as the correction pressure, and the ratio of the rated pressure to the correction pressure is used as the pressure correction coefficient for the water tank of a single-stage equipment.

[0049] The product of the current load factor and the pressure correction factor of a single-stage equipment water tank is used as the health degradation value of the single-stage equipment water tank. The maximum value of the health degradation value of each level of equipment water tank is taken to obtain the equipment health status index.

[0050] Specifically, the equipment health status index satisfies the following relationship: ; in, Indicates the equipment health status index; Indicates the first Level equipment in The operating current at any given moment; Indicates the first Rated current of the equipment; factory-set parameters of the equipment. Indicates the first Level equipment in The water pressure at any given time; Indicates the first Rated pressure of the equipment; This represents the preset minimum pressure lower limit coefficient, which is set to 0.1 in this embodiment. This represents the total number of stages in the cascaded system.

[0051] The health degradation value of a single-stage equipment water tank, combined with the inherent characteristic that current consumption and operating efficiency are inversely proportional under the same water supply pressure, transforms the physical phenomenon of equipment energy efficiency decline into a quantifiable numerical indicator through the product of the aforementioned two coefficients. The worse the equipment's health status (the lower the efficiency), the greater the current required to maintain a given pressure, resulting in a higher current load coefficient. Simultaneously, the pressure correction coefficient also increases due to the increased deviation from operating conditions. Ultimately, the product of these two factors significantly increases, thus accurately characterizing the degree of health degradation of the single-stage equipment. A larger product value indicates poorer equipment energy efficiency and a more deteriorated health status.

[0052] By adopting a conservative evaluation method that takes the maximum value, the control system can always focus on the equipment with the worst health status, so that its control strategy is adapted to the actual operating capacity of the equipment, effectively avoiding control failure, equipment failure or even system cascading failure caused by ignoring equipment degradation.

[0053] S4: Preset multi-level risk classification thresholds and make judgments based on comprehensive risk indicators to determine the current risk level of the box-type negative pressure-free equipment and complete the energy-saving treatment of the box-type negative pressure-free equipment.

[0054] In response to the comprehensive risk index being less than the preset threshold , If the box-type negative pressure-free equipment is in super-optimal mode, it will respond when the comprehensive risk index is greater than or equal to the preset threshold. And less than the preset threshold , If the box-type negative pressure-free equipment is in optimized mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. And less than the preset threshold , If the box-type negative pressure-free equipment is in safe mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. If so, the box-type negative pressure-free equipment is in protection mode.

[0055] The operation control of the box-type negative pressure cascade system is divided into four operating modes: super-optimal mode, optimization mode, safety mode, and protection mode.

[0056] Super Optimal Mode: The primary equipment water tank prioritizes direct water supply by relying on the existing pressure of the municipal water network, minimizing the start-stop frequency and operating time of the booster pump and reducing booster energy consumption; the water storage target of the primary equipment water tank is set at 60% of the maximum water level, which avoids ineffective energy consumption due to excessive water storage while meeting the basic buffer requirements of the system; all levels of variable frequency water supply equipment adopt the most efficient frequency control algorithm, which adjusts the equipment operating frequency to the highest energy efficiency range based on accurately matching the end-user water demand, thereby maximizing the overall energy efficiency of the system.

[0057] Optimized Mode: The water level in the primary equipment tank is maintained at 70% of the maximum water level, which improves the buffering capacity compared to the super-optimal mode, while avoiding the increase in energy consumption caused by excessively high water levels, thus achieving a dynamic balance between buffering performance and water storage energy consumption. Model Predictive Control (MPC) algorithms are introduced for water tanks at all levels of equipment, and control priorities are allocated differently according to the equipment health status index. For equipment with good operating efficiency, energy-saving frequency control is given priority; for equipment with deteriorating efficiency, the stability of the outlet water pressure is given priority, taking into account both the overall energy-saving effect and operational reliability of the system.

[0058] Safety Mode: The water tank of the primary equipment is increased to 85% of its maximum water level, significantly enhancing the hydraulic buffering capacity of the system to cope with sudden water usage disturbances or fluctuations in municipal pipeline pressure; the booster pump set adopts a rotation operation mechanism to balance the running time of each pump and avoid the accelerated efficiency decline and failure risk caused by long-term overload operation of a single pump; the frequency converters at all levels are locked at a level not lower than 60% of the rated frequency to maintain basic energy-saving effects while ensuring stable water supply pressure and safe operation of equipment.

[0059] Protection Mode: The negative pressure device of the primary equipment water tank only maintains the basic water supply function. The operating frequency of the booster pump no longer follows the energy-saving logic, but is dynamically adjusted according to the real-time water level of the water tank, prioritizing the water tank storage and basic water supply. The frequency converters of the secondary and subsequent equipment water tanks directly reduce their operating frequency to 40% of the rated value, actively reducing the equipment operating load and energy consumption output, sacrificing short-term energy-saving effects to ensure that the equipment operates within a safe load range, avoiding water supply interruption and long-term energy waste caused by equipment overload damage, and ensuring the core function of continuous water supply of the system.

[0060] The grading thresholds of the comprehensive risk indicators and the control parameters of each operating mode are based on the long-term historical operating data of the box-type negative pressure cascade system. The corresponding values ​​of the comprehensive risk indicators under different working conditions and the actual operating status of the system under the corresponding values ​​can be flexibly adjusted according to the actual application scenario and system configuration.

[0061] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control, characterized in that, include: Obtain the operating parameter data of the box-type negative pressure cascade equipment, perform preprocessing, and construct the system state vector; Based on the system state vector, and taking into account the topological water supply characteristics of the box-type negative pressure cascade equipment, the buffer capacity coefficient of each equipment tank is determined differently. The product of the buffer capacity coefficient and the absolute value of the flow rate change rate is used as the disturbance characteristic index of each equipment tank. The real-time load rate and disturbance characteristic index of each equipment tank are coupled and calculated to quantify the instantaneous risk value of each equipment tank. Based on the instantaneous risk value of each equipment tank and the cumulative effect of the disturbance characteristic index within the preset time window, the overall disturbance index of the cascade system is calculated. Based on the current load coefficient and corrected pressure of the single-stage equipment in the cascade system, the health status index of the water tanks of each stage equipment is calculated. The overall disturbance index of the system is multiplied by the health status index of the equipment to construct a comprehensive risk index of the current energy-saving level of the cascade system. The system presets multiple risk classification thresholds and makes judgments based on comprehensive risk indicators to determine the current risk level of the box-type negative pressure-free equipment and completes the energy-saving treatment of the box-type negative pressure-free equipment. The calculation method for the disturbance characteristic index includes: Calculate the flow rate change rate of each water tank at the level to be analyzed and take the absolute value. Multiply the absolute value by the buffer capacity coefficient to obtain the disturbance characteristic index of the water tank at the level to be analyzed. The calculation method for the overall system disturbance index includes: The cumulative energy of the disturbance is characterized by the integral value of the disturbance characteristic index within a preset time window calculated by definite integral. The average disturbance intensity is obtained by dividing the integral value by the length of the time window, and then the disturbance cumulative effect factor is obtained by negative exponential transformation and normalization. Multiply the instantaneous risk value of each equipment tank by the corresponding disturbance cumulative effect factor to obtain the fusion risk of each equipment tank. Take the maximum value of the fusion risk of each equipment tank to obtain the overall disturbance index of the cascaded system.

2. The energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control according to claim 1, characterized in that, The steps for obtaining the buffer capacity coefficient include: In response to the case that the box-type negative pressure-free cascade equipment is the primary equipment water tank, the ratio of the current water level of the primary equipment water tank to the maximum water level of the corresponding water tank is used as the relative water level coefficient to reflect the buffering capacity coefficient of the primary equipment water tank. Any water tank other than the primary equipment tank is used as the water tank to be analyzed. The ratio of the real-time outlet pressure of the water tank preceding the water tank to be analyzed to the maximum outlet pressure of the water tank preceding the water tank within a preset time period is used as the relative pressure coefficient to reflect the buffering capacity coefficient of the water tank to be analyzed.

3. The energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control according to claim 1, characterized in that, Calculate the health status index of water tanks at each level of equipment, including: For each stage of equipment water tank, the ratio of real-time operating current to rated current is calculated to obtain the current load factor of the single-stage equipment. The maximum value of real-time outlet pressure and lower pressure threshold is calculated as the correction pressure, and the ratio of rated pressure to correction pressure is used as the pressure correction factor of the single-stage equipment water tank. The product of the current load factor and pressure correction factor of the single-stage equipment water tank is used as the health degradation value of the single-stage equipment water tank. The maximum value of the health degradation value of each stage of equipment water tank is taken to obtain the equipment health status index.

4. The energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control according to claim 3, characterized in that, The lower pressure threshold is the product of a preset minimum coefficient and the rated pressure of the corresponding equipment.

5. The energy-saving method for a box-type negative pressure-free equipment based on risk-level dynamic control according to claim 1, characterized in that, Based on comprehensive risk indicators, the current risk level of the box-type negative pressure-free equipment is determined, including: In response to the comprehensive risk index being less than the preset threshold If the box-type negative pressure-free equipment is in super-optimal mode, it will respond when the comprehensive risk index is greater than or equal to the preset threshold. And less than the preset threshold If the box-type negative pressure-free equipment is in optimized mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. And less than the preset threshold If the box-type negative pressure-free equipment is in safe mode, it will be in response to the comprehensive risk index being greater than or equal to the preset threshold. If so, the box-type negative pressure-free equipment is in protection mode.

6. The energy-saving method for box-type negative pressure-free equipment based on risk-level dynamic control according to claim 1, characterized in that, The preprocessing steps include: An anomaly detection method based on the safe operating boundary of the equipment is adopted to identify and remove operating parameter data that exceeds the reasonable range. Linear interpolation is used to fill in the missing time series data. Data standardization maps the parameters of each dimension to the [0,1] interval to eliminate the difference in units.

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