Security degree analysis method for water supply system

Abstract

The invention discloses a guarantee degree analysis method for a water supply system, the water supply system is a system formed by a forebay and a water delivery pump group, the method comprises the following steps: collecting the water inflow of the forebay and the performance parameters of a plurality of water delivery pumps for measuring the availability of the water delivery pumps in real time, the performance parameters at least comprising the water delivery amount and the power; according to the water inflow and the performance parameters collected in real time, instantaneous supportability is obtained, and according to the water inflow and the performance parameters in the historical time window, theoretical supportability is obtained; and according to the instantaneous supportability and the theoretical supportability, obtaining a comprehensive supportability index for judging the guarantee degree. Through a plurality of parameters acquired in real time, the one-sidedness problem that the prior art depends on a single index is solved. Theoretical supportability is calculated in combination with data in a historical time window, future risks are predicted, and real-time disjunction with historical data is avoided. By integrating the instantaneous supportability and the theoretical supportability, a comprehensive supportability index considering the real-time state and the long-term trend is formed, and misjudgment is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the field of water supply system analysis, and in particular relates to a security analysis method for a water supply system. Background Art

[0002] In water supply systems such as waterworks, the coordinated operation of forebays (such as clear water tanks) and pump systems is crucial for ensuring water supply stability. The forebay must balance water storage and supply demand, while the pump systems must dynamically adjust water delivery based on real-time operating conditions to meet pipe network pressure, user demand, and equipment safety requirements. Therefore, real-time assessment and optimization of system reliability is a long-standing concern within the water industry.

[0003] Existing technologies often rely on single indicators (such as equipment availability or flow stability) to assess reliability, lacking a comprehensive analysis of multiple dimensions, including forebay water storage capacity, equipment performance, and energy efficiency. For example, traditional methods might only determine equipment availability based on instantaneous flow or power thresholds, but they cannot predict future forebay water sufficiency or whether equipment will fail due to chronic overload.

[0004] Furthermore, while some studies have proposed long-term trend analysis based on historical data (such as equipment failure rate statistics), they lack the ability to dynamically correlate instantaneous operating conditions with historical performance. For example, existing technologies make it difficult to assess future water supply security risks during periods of instantaneous low water inflow by combining historical forebay water storage data.

[0005] Furthermore, existing technologies lack a direct mapping between equipment performance parameters (such as water supply and power efficiency) and system reliability, resulting in delayed and untargeted alarm mechanisms. For example, while a drop in motor power might trigger an alarm, it doesn't correlate this with an assessment of its impact on overall water supply capacity.

[0006] In general, existing technologies in the field of water supply system security assessment have core problems such as a single evaluation dimension, insufficient coordination between real-time and historical data, and weak correlation between equipment performance and security. Summary of the Invention

[0007] The present invention provides a method for analyzing the security of a water supply system. Based on real-time data collection, it constructs a multi-dimensional indicator system and conducts a collaborative analysis of instantaneous security and theoretical security to solve the problems of the existing technology in the field of water supply system security assessment, such as a single evaluation dimension, insufficient coordination between real-time and historical data, and weak correlation between equipment performance and security.

[0008] The technical solution adopted in the present invention is:

[0009] A method for analyzing the security of a water supply system, wherein the water supply system is a system formed by a forebay and a water pump group, the method comprising:

[0010] collecting in real time the water inflow of the forebay and performance parameters of multiple water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery volume and power;

[0011] Obtain instantaneous security based on the water intake and performance parameters collected in real time, and obtain theoretical security based on the water intake and performance parameters within a historical time window;

[0012] According to the instantaneous security and the theoretical security, a comprehensive security index for judging the security degree is obtained.

[0013] The security analysis method for a water supply system described in the present invention also includes the following additional technical features:

[0014] According to the water intake and performance parameters collected in real time, instantaneous security is obtained, specifically:

[0015] According to the water inflow, the instantaneous water production capacity guarantee is obtained;

[0016] Determining the availability of the corresponding water pump according to the performance parameter, and obtaining instantaneous equipment availability guarantee according to the number of available water pumps;

[0017] Obtaining instantaneous water delivery capacity assurance based on the available water delivery volume of the water delivery pump;

[0018] Obtaining instantaneous power security according to the available power of the water pump;

[0019] Instantaneous security is obtained based on the instantaneous water production capacity security, instantaneous equipment availability security, instantaneous water delivery capacity security, and instantaneous power security.

[0020] The instantaneous water production capacity guarantee, instantaneous equipment availability guarantee, instantaneous water delivery capacity guarantee, and instantaneous power guarantee are specifically:

[0021] If the water inflow is less than the instantaneous minimum water inflow, or greater than the instantaneous maximum water inflow, the instantaneous water production capacity guarantee is 0; otherwise, the instantaneous water production capacity guarantee is 1;

[0022] If the quantity availability of the water pumps is less than the preset availability threshold, the instantaneous equipment availability guarantee is 0; otherwise, the instantaneous equipment availability guarantee is 1;

[0023] If the water delivery volume of the available water delivery pump is less than the expected water delivery volume, the instantaneous water delivery capacity guarantee is 0; otherwise, the instantaneous water delivery capacity guarantee is 1;

[0024] If the available power of the water pump is less than the rated total power, the instantaneous power guarantee is 0; otherwise, the instantaneous power guarantee is 1.

[0025] Instantaneous minimum water inflow, instantaneous maximum water inflow, preset availability threshold, expected water delivery, and rated total power, specifically:

[0026] The instantaneous minimum water inflow is determined according to the minimum reserved water volume of the forebay and the required water supply volume within the water supply cycle;

[0027] The instantaneous maximum water inflow is determined according to the volume of the forebay and the required water supply during the water supply cycle;

[0028] The preset availability threshold is determined based on the safety factor of the water supply system;

[0029] The expected water supply volume is determined based on the expected unsupplied water volume during the water supply cycle.

[0030] Get instant security, specifically:

[0031] The instantaneous security is the product of the instantaneous water production capacity security, the instantaneous equipment availability security, the instantaneous water delivery capacity security, and the instantaneous power security;

[0032] When the instantaneous security is 0, it is determined that the water supply system does not meet the instantaneous security requirement.

[0033] According to the water intake and the performance parameters within the historical time window, the theoretical guarantee is obtained, specifically:

[0034] According to the water inflow in the historical time window, the theoretical water inflow is obtained through the time average value, and the theoretical water production capacity is guaranteed by the theoretical water inflow;

[0035] According to the performance parameters in the historical time window, the availability of the water pump at multiple moments is determined to obtain a theoretical availability rate, and the theoretical equipment availability guarantee is obtained through the theoretical availability rate;

[0036] According to the water delivery volume of the water delivery pump available in the historical time window, the theoretical water delivery volume is obtained, and the theoretical water delivery capacity guarantee is obtained through the theoretical water delivery volume;

[0037] Obtain theoretical power according to the power of the water pump available in a historical time window, and obtain theoretical power security through the theoretical power;

[0038] Theoretical security is obtained through the theoretical water production capacity security, theoretical equipment availability security, theoretical water delivery capacity security and theoretical power security.

[0039] According to the instantaneous security and the theoretical security, a comprehensive security index is obtained, which is specifically:

[0040] Obtaining a comprehensive security index based on a weighted average of the instantaneous security and the theoretical security;

[0041] When the comprehensive security index is greater than or equal to the security threshold, it is determined that the water supply system is secure.

[0042] If the water supply system is secure,

[0043] According to the water inflow within the historical time window, the water production guarantee degree is obtained;

[0044] Obtain equipment availability based on performance parameters within the historical time window;

[0045] The power guarantee degree is obtained based on the power of the available water pump in the historical time window;

[0046] The water supply security is obtained based on the water supply of the available water supply pumps within the historical time window;

[0047] A security degree measurement index for evaluating the security degree is obtained based on the water production security degree, equipment availability, power security degree, and water volume security degree.

[0048] The security measurement indicators are as follows:

[0049]

[0050] in is the water production guarantee, OA is the equipment availability, PCGD is the power guarantee, WSSR is the water volume guarantee, G d is a security measurement indicator, and the security measurement indicator is positively correlated with the security of the water supply system.

[0051] The present invention also discloses a water supply system security analysis system, comprising:

[0052] IoT platform, used for data collection, transmission, call, calculation and display;

[0053] A data acquisition module, configured to collect in real time the water inflow of the forebay and performance parameters of a plurality of water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery and power;

[0054] Data storage module, used to store parameters, collected data and calculation results required during system operation;

[0055] a data calculation module for obtaining instantaneous security based on the water intake and the performance parameters collected in real time, and obtaining theoretical security based on the water intake and the performance parameters within a historical time window; and obtaining a comprehensive security index based on the instantaneous security and the theoretical security;

[0056] The message push module is used to push message alarms based on the security analysis of the water supply system.

[0057] Due to the adoption of the above technical solution, the beneficial effects achieved by the present invention are as follows:

[0058] 1. In this invention, the water inflow into the forebay and the performance parameters of multiple water pumps used to measure their availability are collected in real time. These performance parameters include at least water delivery and power. Comprehensive, multi-dimensional data collection, through real-time collection of core parameters such as forebay water inflow and water delivery and power from water pumps, addresses the one-sided reliance on a single indicator in existing technologies. This provides a data foundation for comprehensive assessment, enabling immediate identification of issues such as insufficient water supply capacity, equipment overload, or excessive power.

[0059] Furthermore, real-time data collection ensures the system's rapid response to transient operating conditions (such as peak water usage and equipment anomalies), compensating for the lag inherent in traditional methods that rely on static thresholds or isolated historical data. Incorporating performance parameters such as water delivery and power into the security assessment directly maps equipment performance status to system security, avoiding the potential for security failure due to equipment performance degradation.

[0060] Theoretical assurance is derived based on the water intake and performance parameters within a historical time window. Based on data within the historical time window (such as the average water intake over the last five minutes and equipment availability trends), theoretical water intake, water delivery, and power are calculated using time averages to predict assurance risks over the next period. Combining historical and real-time data solves the disconnect between instantaneous and historical data found in existing technologies.

[0061] Based on the instantaneous security and the theoretical security, a comprehensive security indicator is derived for determining security. This comprehensive security indicator combines instantaneous risk and historical trends, avoiding the limitations of a single indicator. For example, while instantaneous security may be zero due to a brief fluctuation, the system security can still be maintained when the theoretical security is normal, reducing misjudgments.

[0062] In summary, the present invention solves the core problems of the prior art in water supply system security assessment, such as one-sidedness, lack of real-time performance, and disconnection between equipment performance and security, by constructing a multi-dimensional comprehensive security assessment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0064] Figure 1 Schematic diagram of a flow chart of a method for analyzing the security level of a water supply system according to one embodiment of the present invention;

[0065] Figure 2 It is a structural schematic diagram of the security analysis system for a water supply system according to one embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to more clearly illustrate the overall concept of the present invention, a detailed description is given below in an exemplary manner in conjunction with the accompanying drawings.

[0067] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0068] like Figure 1 As shown, a method for analyzing the security of a water supply system is provided, wherein the water supply system is a system formed by a forebay and a water pump group. The method comprises:

[0069] S100: collecting the water inflow of the forebay in real time, and performance parameters of a plurality of water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery volume and power.

[0070] The core goal of this step is to provide basic data support for subsequent security analysis through multi-dimensional real-time data collection. By simultaneously obtaining the water inflow of the forebay and the performance parameters of the water pump (such as water delivery and power), the current operating status of the system can be fully reflected, laying a data foundation for the calculation of instantaneous security and theoretical security.

[0071] It is understandable that in the water supply scenario of a waterworks, the front pool is a clear water pool, into which water is continuously input from various pipes. At the same time, the water supply pump draws water from the front pool and delivers it to users with a certain height difference.

[0072] Clear water tanks are a crucial component of a waterworks' process. They primarily store clean water after a series of purification processes, including coagulation, sedimentation, and filtration. One of their functions is to regulate water flow, ensuring sufficient water during peak demand periods to meet the needs of urban residents and industry. During low demand periods, they store purified water to ensure continuous production at the waterworks.

[0073] Specifically, the water inflow is the amount of water continuously fed into the forebay from various pipes. The water delivery is the amount of water pumped from the forebay by the water delivery pump and delivered to the user at a certain height difference.

[0074] Turbine flowmeters are installed in the water inlet of the forebay and the inlet and outlet pipes of the water pump to measure the water inflow in real time (unit: m 3 / s) and the water delivery volume of the water delivery pump (unit: m 3 / s). The turbine flowmeter converts the flow signal into an electrical signal through the proportional relationship between the turbine speed and the flow velocity.

[0075] Install a three-phase energy meter (such as a three-wattmeter or two-wattmeter) at the motor end of the water pump to collect the input power (unit: kW) in real time.

[0076] This step avoids the one-sidedness of relying on a single indicator through the comprehensive collection of parameters such as water intake, water delivery, and power, and provides comprehensive data support for subsequent security analysis.

[0077] It should be noted that in order to ensure the real-time nature of data collection, high-frequency data collection (such as once per second) is used to ensure the rapid capture of instantaneous working conditions (such as water usage peaks or equipment abnormalities), thereby solving the lag problem of traditional methods relying on static thresholds or isolated historical data.

[0078] In this step, data quality is improved by cleaning and standardizing the data to eliminate noise and ensure the accuracy of subsequent calculations. Missing values are filled using interpolation, and outliers (such as power spikes) are identified and marked using statistical methods (such as the 3σ principle). Furthermore, the dimensions of different sensors are standardized through minimum-maximum standardization or Z-score standardization, for example, converting pressure values from MPa to a standardized value.

[0079] The data after data cleaning and standardization pre-processing is wirelessly transmitted to the IoT platform via the MQTT protocol, ensuring low latency and high reliability. It is suitable for complex environments in water supply scenarios (such as electromagnetic interference in pump rooms).

[0080] It is understandable that in this step, water delivery and power are selected as the core parameters for measuring availability because they directly reflect the real-time output capacity and energy consumption status of the water pump. Of course, other parameters (such as temperature and vibration) can also be used as auxiliary indicators to trigger equipment abnormality alarms (such as marking the equipment as unavailable when the temperature exceeds 70°C or the vibration intensity exceeds a threshold), and this invention does not limit this.

[0081] In summary, this step realizes multi-dimensional real-time perception of the operating status of the water supply system, provides a reliable data basis for subsequent security assessments, and solves the assessment bias problem caused by the single data dimension of traditional methods.

[0082] S200: Obtain instantaneous security based on the water intake and the performance parameters collected in real time, and obtain theoretical security based on the water intake and the performance parameters within a historical time window.

[0083] The core objective of this step is to evaluate the system's instantaneous support capability at the current moment and its theoretical support capability within the near-term time window through analysis of multi-dimensional real-time data and historical trend data, providing a foundation for subsequent comprehensive support level judgments. This dual assessment of instantaneous and theoretical data not only captures instantaneous system risks (such as power overruns or equipment unavailability) but also predicts long-term trends (such as insufficient water storage in the forebay or equipment aging), thereby addressing the technical issues of traditional methods' one-sided and lack of dynamic assessments.

[0084] For instantaneous security, the real-time water inflow is based on whether it is within the preset instantaneous minimum water inflow (such as 200m 3 / h) and instantaneous maximum water inflow (such as 800m 3 / h) to judge the instantaneous water production capacity security. Count the ratio of the number of available water pumps to the total number (for example, at least 6 out of 10 pumps are available) to judge the instantaneous equipment availability security. 3 / h) and the expected water delivery (such as 1000m 3 / h) to determine the instantaneous water delivery capacity. Calculate whether the real-time total power (e.g., 450kW) exceeds 1.1-1.3 times the rated total power (e.g., 400kW, with a maximum allowable power of 520kW) to determine instantaneous power reliability. Instantaneous reliability is determined using four sub-indicators.

[0085] This step uses real-time linkage judgment of multi-dimensional indicators to avoid misjudgment due to a single indicator (such as normal power but insufficient water delivery), thereby improving the robustness of the assessment.

[0086] For theoretical assurance, calculate the average water inflow in the historical time window (such as the last 5 minutes) (such as the theoretical water inflow is 250m 3 / h) to determine the theoretical water production capacity guarantee. Calculate the average value of equipment availability in the historical window (such as 90% availability) to determine the theoretical equipment availability guarantee. Calculate the average water delivery volume in the historical window (such as the theoretical water delivery volume is 1100m 3 / h) to determine the theoretical water delivery capacity. Analyze historical power averages (e.g., theoretical power of 420kW) to determine the theoretical power capacity. Theoretical capacity is determined using four sub-indicators.

[0087] In this step, the real-time linkage of four-dimensional indicators ensures that the system has sufficient water production, equipment, water delivery, and power guarantee capabilities at the current moment, avoiding immediate failures (such as power overruns or equipment unavailability). Based on trend analysis of historical averages, future guarantee risks (such as insufficient water storage or equipment aging) are predicted to provide a forward-looking basis for operation and maintenance. By coordinating instantaneous data with historical data within the historical time window, for example, the instantaneous guarantee may be 0 due to a short-term fluctuation in water inflow, but the system can still maintain operation when the theoretical guarantee is normal, avoiding misjudgments and improving assessment flexibility.

[0088] In summary, this step solves the defects of traditional methods that rely on a single indicator or isolated historical data, realizes dynamic, multi-dimensional, real-time and historical coordinated security assessment, and improves the accuracy of water supply security analysis in the water industry.

[0089] S300: Obtaining a comprehensive security index for judging security level based on the instantaneous security and the theoretical security.

[0090] The core goal of this step is to generate a dynamic and adjustable comprehensive security indicator by integrating instantaneous security and theoretical security, so as to balance the real-time risk of the system at the current moment with the long-term risk of historical trends, and solve the problem of one-sided evaluation caused by traditional methods relying only on a single time dimension.

[0091] By integrating instantaneous security and theoretical security, a comprehensive security index is obtained to judge the security level. Specifically, the comprehensive security index is calculated by weighted average.

[0092] ZZ t =α·SS t +(1-α)·LL t

[0093] Among them, α is a user-configurable weight coefficient, which is used to adjust the weight ratio of instantaneous and historical security in the comprehensive evaluation, so that the system can dynamically adjust the evaluation strategy according to actual needs.

[0094] SS t For instant security; LL t For theoretical protection.

[0095] When the comprehensive indicator is ≥ the threshold, the system is judged to be secure; otherwise, an alarm is triggered and the root cause of the problem is located.

[0096] It is understandable that when α = 1, only instantaneous security is relied upon (applicable to emergency response scenarios). When α = 0, only theoretical security is relied upon (applicable to long-term planning or equipment maintenance scenarios). When 0 < α < 1, a dynamic balance is established between instantaneous and historical data (e.g., α = 0.7 emphasizes real-time performance, and α = 0.3 emphasizes long-term trends).

[0097] The weighting parameters are determined based on the water supply during the current time period within the historical water supply cycle. During peak water usage periods (e.g., 6:00 PM to 8:00 PM), α is set to 0.7, prioritizing whether instantaneous water delivery meets demand to avoid water supply interruptions. During low nighttime usage periods (e.g., 11:00 PM to 5:00 AM), α is set to 0.3, prioritizing historical trend analysis (e.g., declining equipment availability) to provide early warning of potential failures.

[0098] Thresholds are set based on water industry SLAs (Service Level Agreements) or user needs. For example, in strict mode, the threshold is set to 1.0, requiring both instantaneous and theoretical assurance to be 1 for a pass. In loose mode, the threshold is set to 0.5, allowing either instantaneous or theoretical assurance to be 1 for a pass.

[0099] This step uses adjustable weight parameters, allowing the system to flexibly switch assessment strategies in different scenarios, such as water supply peaks and valleys, equipment maintenance, and emergency response, avoiding "one-size-fits-all" judgments and improving assessment flexibility. If the instantaneous security is 0 due to a brief flow fluctuation, but the theoretical security is normal (historical water delivery is stable), when α = 0.3, the comprehensive index may still be greater than the threshold (such as 0.7), avoiding unnecessary downtime and reducing the rate of false positives.

[0100] In summary, this step solves the defects of traditional methods that cannot dynamically balance real-time and historical data and lack scenario adaptability, and realizes a configurable, explainable and scalable comprehensive security assessment.

[0101] As a preferred embodiment of the present invention, instantaneous security is obtained based on the water intake and performance parameters collected in real time, specifically:

[0102] According to the water inflow, the instantaneous water production capacity guarantee is obtained;

[0103] Determining the availability of the corresponding water pump according to the performance parameter, and obtaining instantaneous equipment availability guarantee according to the number of available water pumps;

[0104] Obtaining instantaneous water delivery capacity assurance based on the available water delivery volume of the water delivery pump;

[0105] Obtaining instantaneous power security according to the available power of the water pump;

[0106] Instantaneous security is obtained based on the instantaneous water production capacity security, instantaneous equipment availability security, instantaneous water delivery capacity security, and instantaneous power security.

[0107] The core goal of this step is to build a four-dimensional assessment system (water production capacity, equipment availability, water delivery capacity, and power security) with instantaneous security through multi-dimensional data collected in real time, so as to comprehensively and accurately reflect the real-time operating status of the water supply system at the current moment and solve the problem of one-sided assessment caused by traditional methods relying on a single indicator.

[0108] Specifically, if the water inflow is less than the instantaneous minimum water inflow or greater than the instantaneous maximum water inflow, the instantaneous water production capacity guarantee is 0; otherwise, the instantaneous water production capacity guarantee is 1. The instantaneous minimum water inflow is determined based on the minimum reserved water volume of the forebay and the required water delivery volume within the water supply cycle; the instantaneous maximum water inflow is determined based on the volume of the forebay and the required water delivery volume within the water supply cycle.

[0109] The core objective of this implementation is to dynamically calculate the safe range of water inflow (instantaneous minimum and maximum water inflow) for the forebay at the current moment through mathematical modeling. This ensures that the forebay water volume meets the minimum fire reserve and regulation capacity requirements while not exceeding the upper limit, thereby avoiding water supply interruptions due to insufficient water or safety risks caused by water overflow. Furthermore, the water inflow threshold is dynamically adjusted based on the demand for water delivery within the water supply cycle, enabling the system to flexibly respond to different operating conditions (such as peak water supply or valley water storage).

[0110] According to the geometric shape of the forebay (such as rectangular, circular or irregular shape), the relationship function Vh = f(Hc) between the water volume Vh and the water level Hc is established. For example, for a rectangular clear water tank:

[0111] V h =L×W×H c (Where L is the pool length, W is the pool width, H c is the current water level)

[0112] By the inverse function Hc=f -1 (Vh), the water volume can be limited (such as the minimum water volume Vh min , Maximum water volume Vh max Convert to the corresponding water level threshold.

[0113] For the minimum water volume Vh min , Maximum water volume Vh max It is understandable that in actual production, due to the limitations of fire reserve water volume and regulating volume, a certain amount of water needs to be left in the forebay, that is, the minimum water volume Vh min At the same time, due to the volume limit of the forebay, there is a maximum water volume upper limit Vh max .

[0114] Real-time calculation of the instantaneous water inflow Iqin at the current moment t , water delivery volume of industrial frequency pump Jqint , Frequency conversion pump water volume Kqin t ,

[0115]

[0116]

[0117] It is understandable that the forebay is generally provided with multiple water inlet pipes, and the water inflow Qin of each water inlet pipe at the current moment is i,t The instantaneous water inflow of the forebay at the current moment is obtained by superposition. t .

[0118] Water delivery pumps generally include two types: power frequency pumps and variable frequency pumps. Variable frequency pumps use a frequency converter to adjust the motor speed, thereby achieving precise control of the pump flow and head. Power frequency pumps operate under power frequency conditions, and the water output remains constant. At the current moment, the water delivery volume of each power frequency pump is Qin j,t The water volume Jqin obtained by superposition is the power frequency pumping volume t , the water delivery volume of each variable frequency pump Qin k,t The water volume Kqin delivered by the variable frequency pump is obtained by superposition t .

[0119] It should be noted that the water delivery pump group may only include the power frequency pump, and the water delivery volume corresponding to the variable frequency pump is set to 0; or the water delivery pump group may only include the variable frequency pump, and the water delivery volume corresponding to the power frequency pump is set to 0. The present invention does not impose any restrictions on this.

[0120] The water supply plan is formulated according to a fixed time period d, which can be set to one day, that is, d = 1440 minutes, or one hour, that is, d = 60 minutes. Now, time t has passed.

[0121] Combined with the water volume limit of the forebay and the water supply plan within a fixed time period, the range of values that the instantaneous water inflow should meet can be obtained.

[0122]

[0123] According to the range of water inflow and instantaneous water inflow, the instantaneous water production capacity guarantee SS1 is obtained. t .

[0124]

[0125] When the instantaneous water production t In [minqin t , maxqin t ], it means that the instantaneous water production capacity meets the requirements and is reliable, which can ensure the normal water supply to the front pool while ensuring that other equipment is in normal operation.

[0126] This embodiment uses real-time calculation of water supply plan and real-time dynamic constraint. For example, during the peak water consumption period (dt is short), if the current water volume is close to the minimum water volume Vh min , will force an increase in water intake to maintain water storage. t , maxqin t ] dual constraints to ensure that the water volume in the front pool is always in a safe range to prevent overflow and depletion.

[0127] Specifically, if the quantity availability of the water pumps is less than a preset availability threshold, the instantaneous equipment availability guarantee is 0; otherwise, the instantaneous equipment availability guarantee is 1, wherein the preset availability threshold is determined according to the safety factor of the water supply system.

[0128] In this embodiment, the primary purpose of improving pump equipment availability is to ensure stable and reliable operation of the pump equipment in the water supply system, thereby meeting user water needs and ensuring smooth production activities. By monitoring and managing equipment availability, potential problems can be promptly identified and resolved, avoiding water supply interruptions or efficiency reductions caused by equipment failures.

[0129] The quantity availability rate (OA) of water delivery pumps refers to the proportion of centrifugal pump equipment in the pump group that can be used normally at a certain time t.

[0130] It should be noted that the availability of a water pump is determined in real time based on performance parameters, such as power. When the power exceeds a certain percentage of the rated power of the water pump, the corresponding water pump is deemed unavailable. Of course, other parameters such as the water pump's flow rate, pressure, speed, temperature, noise, vibration, etc. can also be used to assist in the determination, and the present invention is not limited to this.

[0131] Instantaneous equipment availability (OA) t = Number of available devices at time t / total number of devices

[0132]

[0133] Among them, B k，t C is the number of variable frequency pumps that can be used. j，t is the number of usable power frequency pumps, and K+J is the total number of variable frequency pumps and power frequency pumps.

[0134] The instantaneous equipment availability guarantee of the water supply system at time t is set as follows:

[0135]

[0136] Among them, avaliablity is the preset availability threshold, which is the requirement for the minimum number of devices to be available. For example, if there are 10 devices, avaliablity can be set to 0.6, which means that at least 6 devices are available. t When the value is not less than one avaliablity, it means that the water supply pump group can meet the water supply demand and is secure.

[0137] It should be noted that the preset availability threshold is determined according to the safety factor of the water supply system. For example, when the safety factor of the water supply system is set to 1.3, the preset availability threshold is 1 / 1.3.

[0138] The safety factor of a water supply system is a redundant parameter introduced during the design, operation, and maintenance of a water supply system to account for unforeseen fluctuations or extreme operating conditions (such as equipment failure, sudden surges in water demand, and power fluctuations). Its core purpose is to ensure the system's continued operation despite various internal and external disturbances, preventing water supply interruptions or performance degradation caused by single device failure or insufficient resources. The safety factor is typically expressed as a multiple (e.g., 1.3) to amplify the design values of key performance indicators (such as power, flow rate, and head) to account for uncertainties in actual operation.

[0139] When the preset availability threshold is 1 / 1.3, it indicates that the current performance indicators just meet the water supply demand and the system operates stably.

[0140] The method for improving the availability of pump group equipment in this embodiment can effectively monitor and manage the operating status of the equipment, ensuring the stability and reliability of the water supply system.

[0141] Specifically, if the water delivery volume of the available water delivery pump is less than the expected water delivery volume, the instantaneous water delivery capacity guarantee is 0, otherwise the instantaneous water delivery capacity guarantee is 1. The expected water delivery volume is determined based on the expected unsupplied water volume within the water supply cycle.

[0142] The core goal of this implementation is to monitor the water delivery capacity of the water pump in real time to determine whether it meets the expected water delivery requirements within the water supply cycle, thereby ensuring that the system can stably supply the required water to users at all times. Through binary judgment (0 or 1), the system can immediately identify the risk of insufficient water delivery capacity, preventing pressure drops or water supply interruptions at the user end caused by insufficient flow, and providing key evidence for subsequent water security analysis.

[0143] According to available equipment C j，t and B k，t , calculate the instantaneous total water delivery of the lifting pump group at time t totalQout t

[0144]

[0145] Among them, Qout j,t 、Qout k,t Available devices C j，t and B k，t The corresponding water supply volume.

[0146] It is understandable that for a water supply plan

[0147] According to the total water demand Qr within the water supply period d (such as 1 hour or 24 hours) d , now time t has passed, water delivery totalQout has been completed t , then the limit on instantaneous water delivery is

[0148]

[0149] When the instantaneous water supply totalQout t Not less than When , it means that according to the current instantaneous water supply, the water supply demand can be met within the remaining time of the specified time range.

[0150] This embodiment achieves accurate assessment and dynamic early warning of instantaneous water delivery capacity by calculating the expected water delivery volume in the remaining time in real time. It can flexibly respond to sudden changes in demand (such as water consumption peaks) and avoid supply and demand imbalances caused by preset fixed values.

[0151] Specifically, if the available power of the water pump is less than the rated total power, the instantaneous power guarantee is 0; otherwise, the instantaneous power guarantee is 1.

[0152] The core objective of this embodiment is to determine whether the system has sufficient power support capability at the current moment by comparing the rated total power with the instantaneous actual total power in real time, to ensure that the equipment operation does not exceed its rated power limit, to avoid equipment overload or shutdown due to insufficient power, and thus to ensure the stability and reliability of the water supply system.

[0153] According to available equipment C j，t and B k，t , calculate the instantaneous rated total power and instantaneous actual total power at time t.

[0154] The instantaneous rated total power is

[0155]

[0156] Among them, Pr j,t and Pr k,t For available device C j，t and B k，t Corresponding rated power.

[0157] The instantaneous actual total power is

[0158]

[0159] Among them, motorP j,t and motorP k,t For available device C j，t and B k，t The corresponding actual power.

[0160] According to the comparison between the instantaneous rated total power and the instantaneous actual total power, the instantaneous power guarantee SS3 is obtained. t .

[0161]

[0162] In actual operation, the instantaneous power is allowed to exceed the rated power, and the maximum does not exceed 1.1 to 1.3 times the rated power. t Not greater than the total rated power totalPr t When the value is 1.1 to 1.3, it indicates that the current instantaneous power can meet the equipment's operating power requirements while ensuring that other equipment is operating normally.

[0163] This embodiment accurately assesses instantaneous power availability, resolving the misjudgment issues caused by traditional methods that rely on static thresholds or isolated parameters. Combining real-time data with dynamic calculations, the system can instantly identify power shortage risks, providing reliable assurance for the stable operation of the water supply system.

[0164] As a preferred embodiment of this embodiment, the instantaneous security is the product of the instantaneous water production capacity security, the instantaneous equipment availability security, the instantaneous water delivery capacity security, and the instantaneous power security;

[0165] When the instantaneous security is 0, it is determined that the water supply system does not meet the instantaneous security requirement.

[0166] The core objective of this implementation is to comprehensively assess the real-time operational status of the water supply system by multiplying four key reliability indicators (instantaneous water production capacity reliability, instantaneous equipment availability reliability, instantaneous water delivery capacity reliability, and instantaneous power reliability) to ensure that all key links meet safety requirements. When the comprehensive instantaneous reliability reaches 0, the system immediately identifies a risk and triggers an alarm, preventing water supply interruptions or equipment failures caused by a single abnormal indicator.

[0167] The instantaneous security of the water supply system is:

[0168] SS t =SS1 t SS2t SS3 t SS4 t

[0169] Only when all sub-security is 1, SS t When it is 1, it means that the water supply system can meet the basic requirements for normal operation of the system and meet the guarantee of water supply demand according to the instantaneous judgment, so as to avoid the single indicator abnormality being ignored. t SS2 t SS3 t SS4 t The value of , determines the problem module, and locates the root cause of the problem.

[0170] This implementation multiplies four key security indicators to achieve a comprehensive, real-time, multi-dimensional assessment of the water supply system across all aspects, ensuring that any anomaly in any single link can be quickly identified and responded to. This design not only enhances the system's risk mitigation capabilities but also provides operators with a clear basis for fault location.

[0171] As a preferred embodiment of the present invention, a theoretical guarantee is obtained based on the water intake and the performance parameters within a historical time window, specifically:

[0172] According to the water inflow in the historical time window, the theoretical water inflow is obtained through the time average value, and the theoretical water production capacity is guaranteed by the theoretical water inflow;

[0173] According to the performance parameters in the historical time window, the availability of the water pump at multiple moments is determined to obtain a theoretical availability rate, and the theoretical equipment availability guarantee is obtained through the theoretical availability rate;

[0174] According to the water delivery volume of the water delivery pump available in the historical time window, the theoretical water delivery volume is obtained, and the theoretical water delivery capacity guarantee is obtained through the theoretical water delivery volume;

[0175] Obtain theoretical power according to the power of the water pump available in a historical time window, and obtain theoretical power security through the theoretical power;

[0176] Theoretical security is obtained through the theoretical water production capacity security, theoretical equipment availability security, theoretical water delivery capacity security and theoretical power security.

[0177] The core goal of this implementation is to comprehensively analyze the long-term operational performance of the water supply system using data from a historical time window and calculate its theoretical reliability. This theoretical reliability combines historical performance across four dimensions: water production capacity, equipment availability, water delivery capacity, and power reliability. This provides a scientific basis for system optimization, fault prediction, and resource allocation, while also serving as a benchmark for real-time reliability assessments.

[0178] It can be understood that, unlike instantaneous assurance, theoretical assurance focuses on the performance in the most recent period of time and infers its assurance based on the calculated theoretical value.

[0179] At time t, select the most recent historical time window T1 (for example, the last 5 minutes, i.e. from t-5min to tmin), and calculate Qin in this time period i,t , Qin j,t and Qin k,t Average value, and set as the theoretical water inlet and outlet of the forebay:

[0180]

[0181] Among them, Qin i,t The instantaneous water inflow of the water inlet pipe at the current moment is added to obtain the total theoretical water inflow of the forebay in the historical time window Qin j,t 、Qin k,t The water delivery of the power frequency pump and the variable frequency pump at the current moment are respectively superimposed to obtain the theoretical water delivery of the power frequency pump and the variable frequency pump in the historical time window. and

[0182] Similarly, the range of theoretical water inlet is obtained based on the theoretical water delivery volume

[0183]

[0184] According to the comparison of theoretical water inflow and value range, the theoretical water production capacity guarantee is obtained.

[0185]

[0186] When the theoretical water production Iqin t In [minIqin t , maxIqin t ], it means that the theoretical water production capacity meets the requirements and is guaranteed.

[0187] In addition, at time t, the historical time window T1 is selected, and the theoretical equipment availability is

[0188]

[0189] The theoretical equipment availability guarantee based on the theoretical equipment availability is

[0190]

[0191] When the instantaneous theoretical availability When the availability is not less than a preset threshold value of availability, it means that the water pump group can meet the power requirements of the equipment operation and is reliable.

[0192] At time t, select the historical event window T1 (for example, the last 5 minutes, i.e. from t-5 min to t min) and calculate the totalQout in this time period t The average value is recorded as the theoretical water delivery rate.

[0193]

[0194] The theoretical water delivery capacity based on the theoretical water delivery volume is as follows:

[0195]

[0196] When the theoretical water supply Not less than When , it means that the theoretical water delivery volume calculated according to the historical event window at the current time point can meet the water delivery demand within the remaining time of the specified time range, and is guaranteed.

[0197] In addition, at time t, select the historical time window T1 and calculate the totalP in this time period t The average value is recorded as the theoretical total power:

[0198]

[0199] The theoretical power guarantee based on the theoretical total power is as follows:

[0200]

[0201] When the theoretical total power Not greater than the rated total power totalPr t When the current theoretical power is , it means that the equipment operating power requirements can be met and it is guaranteed.

[0202] The theoretical guarantee is obtained through the theoretical water production capacity guarantee, theoretical equipment availability guarantee, theoretical water delivery capacity guarantee and theoretical power guarantee. The theoretical guarantee is specifically:

[0203] LL t =LL1 t LL2 t LL3 t LL4 t

[0204] When LL tWhen it is 1, it means that the water supply system can meet the basic requirements for normal operation and the guarantee of water delivery according to the current theoretical performance, and the entire system is reliable.

[0205] As a preferred embodiment of the present invention, a comprehensive assurance index is obtained based on the instantaneous assurance and the theoretical assurance, specifically:

[0206] Obtaining a comprehensive security index based on a weighted average of the instantaneous security and the theoretical security;

[0207] When the comprehensive security index is greater than or equal to the security threshold, it is determined that the water supply system is secure.

[0208] The core goal of this implementation is to comprehensively assess the real-time operational status and long-term stability of a water supply system by integrating instantaneous and theoretical reliability, thereby more comprehensively determining whether the system meets reliability requirements. Instantaneous reliability reflects the system's current real-time risk, while theoretical reliability reflects historical operating trends. A weighted average of the two can avoid the limitations of a single dimension.

[0209] ZZ t =α·SS t +(1-α)·LL t

[0210] Among them, ZZ t is the comprehensive security index, and α is the weighting coefficient, α∈[0,1]. It is used to adjust the weight ratio of instantaneous and historical security in the comprehensive assessment, enabling the system to dynamically adjust the assessment strategy based on actual needs. When α is 0, the comprehensive security index is theoretical security; when α is 1, the comprehensive security index is instantaneous security; if it is between 0 and 1, the value of theoretical and instantaneous security is comprehensively considered.

[0211] The weighting parameters are determined based on the water supply during the current time period within the historical water supply cycle. During peak water usage periods (e.g., 6:00 PM to 8:00 PM), α is set to 0.7, prioritizing whether instantaneous water delivery meets demand to avoid water supply interruptions. During low nighttime usage periods (e.g., 11:00 PM to 5:00 AM), α is set to 0.3, prioritizing historical trend analysis (e.g., declining equipment availability) to provide early warning of potential failures.

[0212] The security threshold is set based on the water supply system's safety factor and industry standards. For example, if residential water systems require high reliability, the threshold may be set at 0.9; and if industrial water systems require high reliability, the threshold may be set at 0.8.

[0213] If the comprehensive security index is ≥ the threshold, the system is secure; otherwise, the "system does not meet security requirements" alarm is triggered.

[0214] This implementation method achieves a comprehensive assessment of the real-time and long-term reliability of the water supply system through weighted fusion of instantaneous and theoretical guarantees, avoiding the limitations of a single indicator while complying with industry standards (such as water supply guarantee rate).

[0215] As a preferred embodiment under this embodiment, if the water supply system is secure,

[0216] According to the water inflow within the historical time window, the water production guarantee degree is obtained;

[0217] Obtain equipment availability based on performance parameters within the historical time window;

[0218] The power guarantee degree is obtained based on the power of the available water pump in the historical time window;

[0219] The water supply security is obtained based on the water supply of the available water supply pumps within the historical time window;

[0220] A security degree measurement index for evaluating the security degree is obtained based on the water production security degree, equipment availability, power security degree, and water volume security degree.

[0221] The core goal of this embodiment is to comprehensively evaluate the long-term reliability of the water supply system based on historical data, and to provide a scientific basis for system optimization, resource allocation and long-term planning through quantitative indicators in four dimensions: water production assurance, equipment availability, power assurance and water volume assurance.

[0222] The average design water inflow Qin of the forebay within the historical time window d is d Compared with the theoretical minimum water inlet min qin t The ratio of water production assurance Used to characterize the degree to which water delivery demand is theoretically met.

[0223]

[0224] Equipment availability is the equipment availability time / equipment total time. That is,

[0225]

[0226] For example, if a device has a fault repair time of 20 hours and an available time of 700 hours within a historical time window of one month (assuming the total time is 720 hours), then the device availability rate = (700 / 720) × 100% ≈ 97.2%.

[0227] High availability means that the equipment can stably support production or services, reducing production interruptions or service quality degradation caused by equipment failure.

[0228] Power guarantee degree PCGD indicates the cumulative rated power ∑ t∈d totalPr t Compared with the cumulative power ∑ t∈d totalP t The ratio reflects the degree to which the available water production capacity guarantees the actual consumption.

[0229]

[0230] The cumulative total water delivery volume TotalQout in the historical time window d,

[0231]

[0232] The water supply security degree WSSR represents the total water supply in the demand history time window d compared with the preset demand quantity Qr d The ratio reflects the degree to which the actual cumulative water supply meets the water demand.

[0233]

[0234] The security measurement indicators are as follows:

[0235] The security degree measurement index G used to evaluate the security degree is obtained based on the water production security degree, equipment availability, power security degree, and water volume security degree. d .

[0236]

[0237] in is the water production guarantee, OA is the equipment availability, PCGD is the power guarantee, WSSR is the water volume guarantee, G d is a security measurement indicator, and the security measurement indicator is positively correlated with the security of the water supply system.

[0238] It is understandable that the security measurement indicator G d It is a value ranging from (1, +∞). The larger the value, the more sufficient the system's guarantee of water supply demand.

[0239] Through multi-dimensional analysis of historical data, this embodiment achieves a quantitative assessment of the long-term reliability of the water supply system.

[0240] like Figure 2 As shown, the present invention also provides a security analysis system for a water supply system, comprising:

[0241] IoT platform, used for data collection, transmission, call, calculation and display;

[0242] A data acquisition module, configured to collect in real time the water inflow of the forebay and performance parameters of a plurality of water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery and power;

[0243] Data storage module, used to store parameters, collected data and calculation results required during system operation;

[0244] a data calculation module for obtaining instantaneous security based on the water intake and the performance parameters collected in real time, and obtaining theoretical security based on the water intake and the performance parameters within a historical time window; and obtaining a comprehensive security index based on the instantaneous security and the theoretical security;

[0245] The message push module is used to push message alarms based on the security analysis of the water supply system.

[0246] The above-mentioned security level analysis system for a water supply system can achieve any effect in the security level analysis method for a water supply system, and will not be described in detail here.

[0247] Anything not described in the present invention can be achieved by adopting or drawing on existing technologies.

[0248] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0249] The foregoing is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the claims of the present invention.

Claims

1. A method for analyzing the security of a water supply system, characterized in that: The water supply system is a system formed by a forebay and a water pump group, and the method includes: collecting in real time the water inflow of the forebay and performance parameters of multiple water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery volume and power; Obtain instantaneous security based on the water intake and performance parameters collected in real time, and obtain theoretical security based on the water intake and performance parameters within a historical time window; According to the instantaneous security and the theoretical security, a comprehensive security index for judging the security degree is obtained.

2. The method for analyzing the security of a water supply system according to claim 1, characterized in that: According to the water intake and performance parameters collected in real time, instantaneous security is obtained, specifically: According to the water inflow, the instantaneous water production capacity guarantee is obtained; Determining the availability of the corresponding water pump according to the performance parameter, and obtaining instantaneous equipment availability guarantee according to the number of available water pumps; Obtaining instantaneous water delivery capacity assurance based on the available water delivery volume of the water delivery pump; Obtaining instantaneous power security according to the available power of the water pump; Instantaneous security is obtained based on the instantaneous water production capacity security, instantaneous equipment availability security, instantaneous water delivery capacity security, and instantaneous power security.

3. The method for analyzing the security of a water supply system according to claim 2, characterized in that: The instantaneous water production capacity guarantee, instantaneous equipment availability guarantee, instantaneous water delivery capacity guarantee, and instantaneous power guarantee are specifically: If the water inflow is less than the instantaneous minimum water inflow, or greater than the instantaneous maximum water inflow, the instantaneous water production capacity guarantee is 0; otherwise, the instantaneous water production capacity guarantee is 1; If the quantity availability of the water pumps is less than the preset availability threshold, the instantaneous equipment availability guarantee is 0; otherwise, the instantaneous equipment availability guarantee is 1; If the water delivery volume of the available water delivery pump is less than the expected water delivery volume, the instantaneous water delivery capacity guarantee is 0; otherwise, the instantaneous water delivery capacity guarantee is 1; If the available power of the water pump is less than the rated total power, the instantaneous power guarantee is 0; otherwise, the instantaneous power guarantee is 1.

4. The method for analyzing the security of a water supply system according to claim 3, wherein the instantaneous Minimum water inflow, instantaneous maximum water inflow, preset availability threshold, expected water delivery, and rated total power, specifically: The instantaneous minimum water inflow is determined according to the minimum reserved water volume of the forebay and the required water supply volume within the water supply cycle; The instantaneous maximum water inflow is determined according to the volume of the forebay and the required water supply during the water supply cycle; The preset availability threshold is determined based on the safety factor of the water supply system; The expected water supply volume is determined based on the expected unsupplied water volume during the water supply cycle.

5. The method for analyzing the security of a water supply system according to claim 3, characterized in that: Get instant security, specifically: The instantaneous security is the product of the instantaneous water production capacity security, the instantaneous equipment availability security, the instantaneous water delivery capacity security, and the instantaneous power security; When the instantaneous security is 0, it is determined that the water supply system does not meet the instantaneous security requirement.

6. The method for analyzing the security of a water supply system according to claim 1, characterized in that: According to the water inflow and the performance parameters within the historical time window, the theoretical guarantee is obtained, specifically: According to the water inflow in the historical time window, the theoretical water inflow is obtained through the time average value, and the theoretical water production capacity is guaranteed by the theoretical water inflow; According to the performance parameters in the historical time window, the availability of the water pump at multiple moments is determined to obtain a theoretical availability rate, and the theoretical equipment availability guarantee is obtained through the theoretical availability rate; According to the water delivery volume of the water delivery pump available in the historical time window, the theoretical water delivery volume is obtained, and the theoretical water delivery capacity guarantee is obtained through the theoretical water delivery volume; Obtain theoretical power according to the power of the water pump available in a historical time window, and obtain theoretical power security through the theoretical power; Theoretical security is obtained through the theoretical water production capacity security, theoretical equipment availability security, theoretical water delivery capacity security and theoretical power security.

7. The method for analyzing the security of a water supply system according to claim 1, characterized in that: According to the instantaneous security and the theoretical security, a comprehensive security index is obtained, which is specifically: Obtaining a comprehensive security index based on a weighted average of the instantaneous security and the theoretical security; When the comprehensive security index is greater than or equal to the security threshold, it is determined that the water supply system is secure.

8. The method for analyzing the security of a water supply system according to claim 7, characterized in that: If the water supply system is secure, According to the water inflow within the historical time window, the water production guarantee degree is obtained; Obtain equipment availability based on performance parameters within the historical time window; The power guarantee degree is obtained based on the power of the available water pump in the historical time window; The water supply security is obtained based on the water supply of the available water supply pumps within the historical time window; A security degree measurement index for evaluating the security degree is obtained based on the water production security degree, equipment availability, power security degree, and water volume security degree.

9. The method for analyzing the security level of a water supply system according to claim 8, characterized in that: The security measurement indicators are as follows: in is the water production guarantee, OA is the equipment availability, PCGD is the power guarantee, WSSR is the water volume guarantee, G d is a security measurement indicator, and the security measurement indicator is positively correlated with the security of the water supply system.

10. A water supply system security analysis system, characterized in that: include: IoT platform, used for data collection, transmission, call, calculation and display; A data acquisition module, configured to collect in real time the water inflow of the forebay and performance parameters of a plurality of water pumps for measuring the availability of the water pumps, wherein the performance parameters at least include water delivery and power; Data storage module, used to store parameters, collected data and calculation results required during system operation; a data calculation module for obtaining instantaneous security based on the water intake and the performance parameters collected in real time, and obtaining theoretical security based on the water intake and the performance parameters within a historical time window; and obtaining a comprehensive security index based on the instantaneous security and the theoretical security; The message push module is used to push message alarms based on the security analysis of the water supply system.

Images