A method and device for leak detection and location in environmental monitoring

Abstract

This application discloses a method and apparatus for leak detection and location in environmental monitoring, relating to the field of sensor technology. The method includes inputting a safe initial current into a sensing cable to acquire a first voltage signal at both ends of the sensing cable within a preset voltage range; determining a target input current and a target voltage range for the sensing cable based on the first voltage signal; acquiring a second voltage signal at both ends of the sensing cable within the target voltage range when the target input current is input into the sensing cable; calculating a first impedance value of the sensing cable based on the second voltage signal; determining the leak location result corresponding to the first impedance value according to a distributed resistance model; and determining the leak location result as the corresponding leak point position on the sensing cable. This application dynamically and collaboratively adjusts the output current of the excitation source and the range of the acquisition module, ensuring the measurement system always operates automatically in its optimal state, thereby achieving high-precision leak point location over an extremely wide impedance variation range and improving system reliability.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a method and device for detecting and locating leaks in environmental monitoring. Background Technology

[0002] Cable-mounted water immersion sensors are core equipment for environmental safety monitoring of modern critical infrastructure. They can be used to detect leaks in locations such as power and environmental data centers, computer rooms, warehouses, and pipe corridors. In practical applications, the sensor cable can be laid in areas prone to leaks. When a leak occurs, the local impedance of the sensor cable changes due to the leak, and leak alarms and location are achieved through real-time monitoring of the impedance change.

[0003] Traditional solutions typically employ a constant current excitation-voltage detection model for leak detection and location. However, due to the complexity of real-world application environments, several problems frequently arise. For instance, depending on the environment, leaks may involve high-impedance pure water or low-impedance sewage. When using a smaller excitation current to monitor low-impedance sewage, the resulting voltage signal is often too small, leading to low location accuracy. Conversely, using a larger excitation current to monitor high-impedance pure water can cause the analog-to-digital converter (ADC) to saturate and fail to perform measurements. Furthermore, prolonged use of large excitation currents can induce electrochemical corrosion and accelerate the aging of sensor cables. Clearly, traditional solutions lack adaptability to varying environmental conditions. Summary of the Invention

[0004] This application provides a method and device for leak detection and location in environmental monitoring, which solves the problems of existing technologies being unable to handle multiple detection environments, having poor accuracy, and being prone to missed detections.

[0005] Firstly, this application provides a method for leak detection and location applied to environmental monitoring, including:

[0006] A safe initial current is input into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range;

[0007] The target input current and target voltage range of the sensing cable are determined based on the first voltage signal; the target voltage range is a sub-range of the preset voltage range.

[0008] When the target input current is input into the sensing cable, a second voltage signal is acquired at both ends of the sensing cable within the target voltage range;

[0009] Based on the second voltage signal, calculate the first impedance value of the sensing cable;

[0010] The location of the leak point corresponding to the first impedance value is determined based on the distributed resistance model; the location of the leak point is the corresponding location of the leak point on the sensing cable.

[0011] In some feasible embodiments, determining the target input current and target voltage range of the sensing cable based on the first voltage signal includes:

[0012] Calculate the second impedance value of the sensing cable based on the first voltage signal and the safe initial current;

[0013] Based on the impedance range in which the second impedance value is located, the target input current and target voltage range corresponding to the sensing cable are determined.

[0014] In some feasible embodiments, determining the target input current and target voltage range corresponding to the sensing cable includes:

[0015] Query the target input current and target voltage range corresponding to the impedance range in the adaptive decision table;

[0016] or,

[0017] Based on the preset decision logic function, the target input current and target voltage range corresponding to the impedance range are obtained.

[0018] In some feasible embodiments, the distributed resistance model includes:

[0019] ;

[0020] in, The first impedance value; ; ; The resistance per unit length of the sensing cable; The distance from the measuring end to the leak point; The matching resistor is the one to which the sensing cable is connected; The impedance at the leakage point.

[0021] In some feasible embodiments, the location result of the leak point corresponding to the first impedance value is determined according to the distributed resistance model, including:

[0022] Determine the first current value and the second current value based on the target input current;

[0023] Obtain the first equivalent impedance value corresponding to the first current value, and the second equivalent impedance value corresponding to the second current value;

[0024] The first current value, the first equivalent impedance value, the second current value, and the second equivalent impedance value are respectively input into the distributed resistance model to solve the impedance of the leak point and the distance from the measuring end to the leak point, so as to obtain the leak point location result.

[0025] In some feasible embodiments, the location result of the leak point corresponding to the first impedance value is determined according to the distributed resistance model, including:

[0026] Based on the distributed resistance model, a two-dimensional relationship table is calibrated to represent the relationship between impedance value, distance from the measuring end to the leak point, and impedance at the leak point.

[0027] Based on the two-dimensional relationship table, the distance from the measuring end corresponding to the first impedance value to the leak point is determined, and the leak point location result is obtained.

[0028] In some feasible embodiments, the method further includes:

[0029] In response to the activation of the continuous monitoring mode, the step of inputting a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range is performed at a preset period.

[0030] In some feasible embodiments, after calculating the first impedance value of the sensing cable based on the second voltage signal, the method further includes:

[0031] Obtain the third impedance value of the sensing cable in the previous cycle;

[0032] If the change in the first impedance value compared to the third impedance value exceeds a preset threshold, then the step of inputting a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range is executed.

[0033] Secondly, this application also provides a leakage detection and location device for environmental monitoring, comprising:

[0034] A programmable excitation module, connected to the sensing cable, is used to input excitation current into the sensing cable;

[0035] A configurable acquisition module is connected to the sensing cable and is used to acquire the voltage signals at both ends of the sensing cable when an excitation current is input to the sensing cable.

[0036] The microcontroller unit is communicatively connected to the programmable excitation module and the configurable acquisition module, and is used to execute the leakage detection and location method for environmental monitoring described in the first aspect.

[0037] In some feasible embodiments, the microcontroller unit includes a memory that stores an adaptive decision table or decision logic function.

[0038] The memory also stores a distributed resistance model and / or a two-dimensional relationship table representing the relationship between impedance value, distance from the measuring end to the leak point, and impedance of the leak point.

[0039] Compared with the prior art, the beneficial effects of this application are:

[0040] (1) Fundamental methodological innovation: It proposes a closed-loop adaptive measurement paradigm of "first make a rough judgment on safety, then optimize and measure in detail", dynamically constructs the optimal measurement system, and solves the fundamental contradiction that the dynamic range and accuracy of a fixed parameter system cannot be achieved at the same time in principle.

[0041] (2) High-precision positioning across the entire range: Through adaptive matching, the measurement signal can fully utilize the resolution of the ADC across the entire range from high-impedance pure water to low-impedance sewage, thereby achieving and maintaining high measurement accuracy across the entire range and significantly reducing positioning error.

[0042] (3) Significantly enhanced system reliability: The method incorporates a safety mechanism. The coarse test stage uses a safe low current, and the decision logic can force the use of a low current setting for low impedance, which fundamentally avoids cable electrolytic corrosion and thermal damage caused by long-term high current, and extends the equipment life.

[0043] (4) High level of intelligence and ease of use: It achieves a "plug and play, set and forget" user experience. The system automatically completes the initial parameter optimization and continuous tracking adjustment without manual intervention, which greatly reduces the technical threshold and cost of deployment, debugging and maintenance.

[0044] (5) Good scalability and flexibility: The adaptive control logic is independent of the specific number of hardware levels. The excitation current level and ADC range can be flexibly configured according to cost and requirements, and it is easy to be ported and expanded in products with different performance levels. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating a method for detecting and locating leaks in environmental monitoring, provided in this application embodiment;

[0047] Figure 2 This is an equivalent model diagram of the distributed resistance of the sensing cable used for positioning calculation in the embodiments of this application;

[0048] Figure 3 This is a schematic diagram of a leakage detection and location device for environmental monitoring provided in an embodiment of this application;

[0049] Figure 4 A schematic diagram illustrating the implementation principle of a programmable excitation module in a water leakage detection and location device applied to environmental monitoring, as provided in an embodiment of this application.

[0050] Figure 5 A schematic diagram illustrating the implementation principle of a configurable acquisition module in a water leakage detection and location device for environmental monitoring, provided in an embodiment of this application.

[0051] Figure 6 A flowchart illustrating the overall process of the apparatus provided in this application performing the method provided in the foregoing embodiments. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application.

[0053] Cable-mounted water immersion sensors are core equipment for environmental safety monitoring of modern critical infrastructure. They detect the physical phenomenon of local impedance changes in the sensing cable (usually a leakage current sensing wire) caused by water leakage, thereby enabling water leakage alarms and location.

[0054] Currently, most mainstream positioning water immersion sensors adopt a constant current excitation-voltage detection model. This model reveals the following inherent defects in complex real-world application scenarios:

[0055] The contradiction between dynamic range and accuracy: The effective measurement range of a sensor is limited by the fixed range of the analog-to-digital converter (ADC) and the fixed value of the excitation current. To detect high-impedance pure water (impedance can reach tens of kiloohms), a small current is required to prevent signal saturation; however, when facing low-impedance sewage (impedance can be as low as tens of ohms), the generated voltage signal is too small, resulting in a poor signal-to-noise ratio and a large positioning error. Conversely, a large current set for accurate sewage measurement will inevitably cause ADC saturation and measurement failure when encountering pure water.

[0056] The contradiction between adaptability and reliability: When a fixed high current is used to monitor wastewater containing electrolytes for a long time, it will cause electrochemical corrosion (electrolysis effect), accelerate the aging of sensor cables, and damage long-term reliability.

[0057] Deployment and maintenance are complex: In order to cope with different on-site water quality, technicians need to manually adjust the sensitivity or perform complex calibration. The process is cumbersome and it is difficult to achieve global optimization, which increases the cost of use and the technical threshold.

[0058] To address the aforementioned technical issues, this application provides a method for leak detection and location in environmental monitoring. By dynamically and collaboratively adjusting the output current of the excitation source and the range of the acquisition module, the measurement system can always operate automatically in its optimal state, thereby achieving high-precision location of leak points within an extremely wide range of impedance variations and improving system reliability.

[0059] It should be noted that the methods and devices provided in this application are not limited to the power and environment monitoring of communication manufacturers, such as computer rooms, power distribution rooms, data centers, base stations, business halls, etc., which all belong to power and environment monitoring (referred to as dynamic environment monitoring). Leakage detection mainly monitors whether there is air conditioning leakage on the ground, whether there is water pipe rupture in key locations, etc., and also includes data and sensors of other types of intelligent devices, such as power supply, battery, anti-theft, door control, etc.

[0060] See Figure 1 The flowchart below illustrates a method for detecting and locating leaks in environmental monitoring, as provided in an embodiment of this application.

[0061] like Figure 1 As shown in the embodiment of this application, a method for leak detection and location applied to environmental monitoring includes the following steps:

[0062] S100: Input a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range.

[0063] Specifically, in the embodiments of this application, the safe initial current can be preset to a sufficiently small current value to ensure that the ACD will not saturate or cause a significant electrolytic effect under any expected impedance. This can fundamentally avoid cable electrolytic corrosion and thermal damage caused by long-term high current, and extend the equipment life.

[0064] The preset voltage range is the voltage measurement range set in the initial stage. This range should cover the voltage variation range of the sensing cable under conditions of no water leakage and possible slight water leakage, so as to effectively capture the first voltage signal. Therefore, the preset voltage range should be preset to the widest voltage range to ensure that the voltage signals at both ends of the sensing cable can be effectively acquired in step S100.

[0065] In some embodiments, the operation of inputting the safe initial current in step S100 can be performed by a programmable excitation module connected to the sensing cable. The programmable excitation module can input different current values ​​into the sensing cable based on different instructions, thereby obtaining corresponding voltage signal feedback. The step of obtaining the voltage signal can be performed by a configurable acquisition module (e.g., a range-switching analog-to-digital converter circuit) connected to the sensing cable. When the configurable acquisition module acquires the voltage signal, it can acquire it based on different ranges, thereby obtaining a more accurate voltage signal.

[0066] S200: Determine the target input current and target voltage range of the sensing cable based on the first voltage signal; the target voltage range is a sub-range of the preset voltage range.

[0067] In this embodiment, after obtaining the voltage signal under the safe initial current, an excitation current and ADC range that can make the expected voltage signal fall within the optimal linear region of the ADC range can be matched according to the different impedance ranges corresponding to the current voltage signal, namely the target input current and the target voltage range. When the target input current and the target voltage range are used to obtain the voltage signal, it can be ensured that the voltage signal is in the optimal linear region of the target voltage range (e.g., 10% to 90% of the full scale), thereby ensuring the accuracy of the obtained voltage signal.

[0068] As can be seen from the above scheme, this application enables the measurement signal to fully utilize the resolution of the ADC in the entire range from high-impedance pure water to low-impedance sewage through adaptive matching, thereby achieving and maintaining high measurement accuracy throughout the entire range and significantly reducing positioning error.

[0069] Specifically, in some embodiments, step S200 can be broken down into:

[0070] S210: Calculate the second impedance value of the sensing cable based on the first voltage signal and the safe initial current.

[0071] In some embodiments, the impedance value (second impedance value) of the sensing cable under the safe initial current can be calculated using the following formula:

[0072] ;

[0073] in, This is the second impedance value, which is a rough estimate of the impedance used to determine the subsequent target input current and target voltage range; This is the first voltage signal; For safe initial current.

[0074] For example, if the safe initial current is 1mA and the first voltage signal is 5V, then the second impedance value is 5V / 1mA = 5kΩ.

[0075] S220: Based on the impedance range where the second impedance value is located, determine the target input current and target voltage range corresponding to the sensing cable.

[0076] In some embodiments, multiple impedance ranges can be preset based on experience. For example, three impedance ranges can be set as follows: low impedance range (0-1kΩ), medium impedance range (1kΩ-10kΩ), and high impedance range (10kΩ-100kΩ), each corresponding to a different target input current and target voltage range. The impedance ranges can also be set to other numbers and other numerical ranges, which are not limited in the embodiments of this application.

[0077] The adaptive control logic proposed in this application embodiment is independent of the specific number of hardware levels. It can flexibly configure the excitation current level and ADC range according to cost and requirements, and is easy to port and expand in products with different performance levels.

[0078] Once the impedance range of the second impedance value is determined, the corresponding target input current and target voltage range can be further determined.

[0079] In some embodiments, the correspondence between impedance range and target input current and target voltage range can be stored in an adaptive decision table. When it is necessary to determine the target input current and target voltage range, they can be obtained by querying the adaptive decision table.

[0080] When constructing the adaptive decision table, we can first determine the ranges that the programmable excitation module and the configurable acquisition module can provide. For example, the programmable excitation module has three constant current output ranges: I1 / I2 / I3, corresponding to extremely high impedance, medium impedance, and extremely low impedance, respectively. The configurable acquisition module has two range ranges: Vr1 / Vr2, corresponding to wide range and high precision range, respectively. Based on the permutations and combinations of the ranges, various range combinations can be obtained, such as combination A (I1+Vr1), combination B (I2+Vr2), combination C (I3+Vr2), combination D (I1+Vr2), etc. After data measurement and experimental verification analysis, the following table can be generated:

[0081]

[0082] It should be noted that the specific values ​​in the table above are for illustrative purposes only. In actual applications, these values ​​can be adjusted to other required values ​​based on experience and scenario needs.

[0083] In some embodiments, a decision logic function can be constructed based on the correspondence between the impedance range and the target input current and target voltage range. When it is necessary to determine the target input current and target voltage range, the decision logic function can be called to automatically calculate the corresponding current value and voltage range based on the impedance range, which will be used as the final target input current and target voltage range.

[0084] For example, when the second impedance value is 2kΩ, it is determined to be in the medium impedance range. At this time, the target input current corresponding to the medium impedance range can be determined to be 5mA and the target voltage range to be 2-8V by consulting the adaptive decision table or through the decision logic function (assuming the preset voltage range is 0-10V, and the target voltage range is its sub-range). This setting of the target voltage range can more accurately cover the voltage changes under medium impedance conditions, improving the accuracy of subsequent measurements.

[0085] This application provides a closed-loop adaptive measurement paradigm of "first making a coarse judgment for safety, then optimizing for fine measurement", which dynamically constructs the optimal measurement system and solves the fundamental contradiction that dynamic range and accuracy cannot be achieved simultaneously in a fixed parameter system.

[0086] S300: When the target input current is input into the sensing cable, the second voltage signal at both ends of the sensing cable is acquired within the target voltage range.

[0087] Specifically, after determining the target input current and target voltage range, the programmable excitation module can input the target input current, for example, 5mA, into the sensing cable. Simultaneously, the acquisition module can be configured to switch to the target voltage range of 2-8V. At this point, because the target input current matches the impedance of the current sensing cable, and the target voltage range is better suited to the voltage output under that impedance, a more accurate second voltage signal can be acquired.

[0088] For example, when the impedance of the sensing cable is 2kΩ and the target input current is 5mA, the voltage signal is 10V. If the target voltage range is set to 8-12V, the voltage signal can be effectively acquired.

[0089] S400: Calculate the first impedance value of the sensing cable based on the second voltage signal.

[0090] Specifically, after obtaining the second voltage signal, according to Ohm's law, the first impedance value is equal to the ratio of the second voltage signal to the target input current:

[0091] ;

[0092] in, This is the second voltage signal; Input current to the target; This is the first impedance value.

[0093] For example, if the second voltage signal is 6V and the target input current is 5mA, then the first impedance value is 6V / 5mA = 1.2kΩ. This first impedance value, compared to the second impedance value calculated in S200, is more accurate and better reflects the true impedance state of the sensing cable due to the use of a more matched excitation current and range.

[0094] S500: Determine the location of the leak point corresponding to the first impedance value based on the distributed resistance model; the location of the leak point is the corresponding location of the leak point on the sensing cable.

[0095] In this embodiment, the location of the leak point can be determined based on a distributed resistance model of the sensing cable. This distributed resistance model considers factors such as the resistance per unit length of the sensing cable, the distance from the measuring end to the leak point, the impedance of the leak point, and the matching resistance. Let the total length of the sensing cable be... (meters), resistance per unit length is (Ω / m). A known matching resistor is connected to the end (far end) of the cable. The leak point divides the cable into two sections, with resistances of [missing information]. and The impedance at the leakage point is .

[0096] In some embodiments, the constructed distributed resistance model may include:

[0097] ;

[0098] in, This is the first impedance value; ; ; The resistance per unit length of the sensing cable; The distance from the measuring end to the leak point; This is the matching resistor for the sensor cable connection.

[0099] See Figure 2 When constructing the distributed resistance model, the physical locations are first defined, including the measuring end, the cable end, the length L of the sensing cable, and the distance L1 from the leak point. During detection, the circuit signal flow is as follows: the excitation current I_s originates from node A on the MCU side of the measuring end, passes through the resistor R1 from the measuring end to the leak point, part of the current flows to ground (GND) through the leak point impedance R_leak (which is connected to the ground path of the leak point), and the other part of the current continues to flow through the resistor R2 from the leak point to the end, and finally flows to ground (GND) through the matching resistor R_term at the end of the cable. The measuring end MCU simultaneously measures the voltage V_s at both ends of the cable.

[0100] In the distributed resistance model, the first impedance value The resistance per unit length of the sensor cable can be calculated based on the previous steps. It can be obtained in advance; the impedance of the leak point is The distance x from the measuring end to the leak point is an unknown parameter. In actual measurement processes, it is usually... The value is much smaller than (especially in the case of wastewater). In order to achieve high-precision solutions for unknown parameters, various methods can be used in the embodiments of this application. Two feasible methods are described below as examples. It should be understood that other existing technologies can also be used as alternative implementation methods.

[0101] Method 1: Iterative approximation method.

[0102] Under this method, step S500 can be broken down as follows:

[0103] S510: Determine the first current value based on the target input current. Second current value Among them, the first current value Second current value The specific value can be determined by selecting two neighboring points based on the neighborhood of the target input current. For example, 100 ± 5% of the target input current can be selected as the first current value and the second current value, respectively. In other embodiments, when determining the target input current in step S200, two target input currents can also be directly determined so that these two target input currents can be determined as the first current value and the second current value, respectively.

[0104] S520: Obtain the first equivalent impedance value corresponding to the first current value and the second equivalent impedance value corresponding to the second current value; in this embodiment, the first equivalent impedance value and the second equivalent impedance value can be calculated based on the method of S400 respectively.

[0105] S530: Input the first current value, the first equivalent impedance value, the second current value, and the second equivalent impedance value into the distributed resistance model to solve the leakage point impedance and the distance from the measuring end to the leakage point, and obtain the leakage point location result.

[0106] In this embodiment, based on the two sets of impedance data obtained in step S520, the impedance of the leakage point can be accurately calculated by solving a system of simultaneous equations. The distance x from the measuring end to the leak point is used to eliminate systematic errors in a single measurement.

[0107] Specifically, by using the method of this embodiment to solve the equations simultaneously, the formula for calculating the distance x from the measuring end to the leakage point can be obtained as follows:

[0108] ;

[0109] The first impedance value obtained through adaptive measurement. Higher precision, and impedance to leakage point is The estimate (obtained through calculation) is more accurate, thus significantly reducing the error of the final calculated x value.

[0110] In some embodiments, the number of measurements can be further increased, i.e., more current values ​​are used as input to obtain more sets of impedance values, and then the impedance of the leakage point can be calculated by averaging, binarization, and calculus. The distance x from the measuring end to the leak point is not limited in this embodiment of the application.

[0111] Method 2: Table lookup and interpolation.

[0112] Under this method, step S500 can be broken down as follows:

[0113] S540: Based on the distributed resistance model, calibrate a two-dimensional relationship table to represent the relationship between impedance value, distance from the measuring end to the leak point, and impedance of the leak point.

[0114] In this embodiment, simulation experiments can be conducted in advance in the laboratory stage based on a pre-constructed distributed resistance model. Experimental data can be recorded for specific sensing cables, and a pre-established "..." model can be built based on the experimental data. A two-dimensional relationship table between "".

[0115] For example, the constructed two-dimensional relationship table can be as follows:

[0116]

[0117] S550: Based on a two-dimensional relational table, determine the distance from the measuring end corresponding to the first impedance value to the leak point, and obtain the leak point location result.

[0118] In actual measurements, based on the calculated and estimated The range (which can be roughly determined by the target voltage range / impedance interval decided in step S200) can be quickly and accurately obtained using a lookup table and bilinear interpolation algorithm. .

[0119] Specifically, during the table lookup process, due to If the value is unknown, you can first find the resistance value closest to the first impedance value in the table. For example, when the first impedance value is 58Ω, there are two resistance values ​​in the table that are close to it, namely x=30m / =100Ω, and x=100m / =30Ω; This indicates two possibilities: a higher impedance leak nearby (30m) or a lower impedance leak further away (100m). Next, the impedance range determined in the previous steps can be used as a reference. If the corresponding impedance range is 66Ω~660Ω, then the leak point impedance is more likely to be around 100Ω, rather than around 30Ω. Furthermore, since sparse sampling points (e.g., 10m interval) are used when constructing the two-dimensional relationship table, to improve accuracy, after determining the target area of ​​the leak point, bilinear interpolation can be performed to calculate a more precise x-value. Specifically, interpolation calculations can be performed using four grid points around the target area to obtain the final leak point location result.

[0120] As can be seen from the above technical solution, the method provided in this application first obtains a first voltage signal with a safe initial current, calculates a rough second impedance value, and then matches the target input current and target voltage range according to the range of the impedance value to ensure that the subsequently acquired second voltage signal is in the optimal linear region, thereby calculating a high-precision first impedance value. Combined with a distributed resistance model, multiple sets of current and impedance data are solved using an iterative approximation method, or a lookup table and interpolation method is used for rapid location, effectively eliminating system errors and improving the accuracy of leak point location. This solves the problem of insufficient measurement accuracy of traditional methods under variable impedance conditions, and achieves precise location of leak points in sensing cables.

[0121] In some embodiments, considering the dynamic changes in impedance caused by factors such as changes in water quality and expansion of the water accumulation area, step S100 in the method described above can be further set as follows:

[0122] S101: In response to the start of continuous monitoring mode, execute at a preset cycle: input a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range.

[0123] For example, when the preset period is set to 10 seconds, the system inputs a safe initial current into the sensing cable every 10 seconds to obtain the first voltage signal, and then performs subsequent impedance calculations and leak location to ensure that leaks and changes in leak conditions can be detected in a timely manner.

[0124] In some embodiments, in addition to triggering step S100 at fixed time intervals, the triggering conditions of S100 can be further set. For example, after calculating the first impedance value in step S400, the impedance value of the previous period (the third impedance value) can also be obtained. If the change in the first impedance value compared to the third impedance value exceeds a preset threshold, such as the change exceeding a certain value (or exceeding a preset percentage), step S100 can be executed immediately to adapt to sudden changes in impedance more quickly, adaptively refit parameters, and improve the sensitivity and accuracy of detection.

[0125] Based on this solution, a "plug and play, set up and forget" user experience is achieved. The system automatically completes initial parameter optimization and continuous tracking and adjustment without manual intervention, greatly reducing the technical threshold and cost of deployment, debugging and maintenance.

[0126] Corresponding to the above method, this application also provides an apparatus for applying the above method.

[0127] See Figure 3 This is a schematic diagram of a leakage detection and location device for environmental monitoring provided in an embodiment of this application.

[0128] like Figure 3 As shown, the apparatus provided in this application may include:

[0129] A programmable excitation module, connected to the sensing cable, is used to input excitation current into the sensing cable. The programmable excitation module can be a digitally programmable constant current source (with multiple levels), which receives instructions from a microcontroller unit (MCU) and outputs at least two different levels (preferably in a tenfold ratio) of constant excitation current.

[0130] In some embodiments, the core of the programmable excitation module may include a high-precision digital-to-analog converter (DAC) or digital potentiometer controlled by an MCU via a digital interface (I²C, SPI), combined with a voltage-controlled current source consisting of a precision operational amplifier and a MOSFET. The output current value is linearly set by changing the digital control word of the DAC.

[0131] In some embodiments, see Figure 4 The structure of the programmable excitation module can include analog circuit sections and digital circuit sections. The MCU of the digital circuit section connects to I... 2The C / SPI interface controls the DAC or digital potentiometer to set the reference voltage for the analog operational amplifier. The analog circuitry includes operational amplifiers, power MOSFETs, and sampling resistors. The operational amplifiers form a feedback amplifier circuit, controlling the output current I_out of the power MOSFET and stabilizing this current using the feedback voltage V_fb of the sampling resistor R_sense. Ultimately, this controlled output current I_out is used to drive the sensing cable (water immersion detection rope).

[0132] A configurable acquisition module is connected to the sensing cable and is used to acquire the voltage signals at both ends of the sensing cable when an excitation current is input to the sensing cable.

[0133] In some embodiments, the configurable acquisition module can internally integrate a programmable gain amplifier (PGA) and an ADC chip, or switch operational amplifier circuits with different feedback resistors via an external analog switch to achieve digital switching of the input range.

[0134] In some embodiments, see Figure 5 The configurable acquisition module can have two sensor signal acquisition and processing schemes: one is to use an external gain switching scheme, in which the MCU gain selection signal is passed through an analog switch array to select the gain resistor network, and after processing by the instrumentation amplifier and the programmable gain amplifier, it is sent to a fixed-range ADC to convert it into a digital output; the other is an ADC chip scheme with integrated PGA, in which the MCU gain selection signal and the output of the instrumentation amplifier work together to the programmable gain amplifier in the chip, and then the digital signal is output by the ADC. Both schemes send the digital output to the MCU for processing. The core difference is whether the gain adjustment relies on external hardware or an integrated module inside the ADC chip.

[0135] A microcontroller unit (MCU), serving as the control core, is communicatively connected to the programmable excitation module and the configurable acquisition module, and is used to execute the leakage detection and location method for environmental monitoring described in any of the foregoing embodiments. The microcontroller unit may internally include a memory storing the control program, impedance-range mapping strategy (adaptive decision table / strategy function), and location parameters for location calculation. These location parameters, related to the sensor cable, are not limited to, but include, the resistance per unit length of the sensor cable and its matching resistance.

[0136] In some embodiments, the memory also stores a distributed resistance model and / or a two-dimensional relationship table representing the relationship between impedance values, the distance from the measuring end to the leak point, and the impedance of the leak point, which is invoked when the aforementioned method is executed.

[0137] See Figure 6This is a general flowchart of the apparatus provided in the embodiments of this application when executing the method provided in the foregoing embodiments; for the specific execution process, please refer to the description in the foregoing method embodiments, which will not be repeated here.

[0138] The solution provided by the device in this application embodiment is similar to the solution described in any of the above method embodiments. Therefore, the specific limitations in the device embodiment can be found in the above-described limitations on the leakage detection and location method applied to environmental monitoring, and will not be repeated here.

[0139] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A method for leak detection and location applied to environmental monitoring, characterized in that, include: A safe initial current is input into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range; The target input current and target voltage range of the sensing cable are determined based on the first voltage signal; The target voltage range is a sub-range of the preset voltage range; When the target input current is input into the sensing cable, a second voltage signal is acquired at both ends of the sensing cable within the target voltage range; Based on the second voltage signal, calculate the first impedance value of the sensing cable; The location of the leak point corresponding to the first impedance value is determined based on the distributed resistance model. The leak location result is the location of the corresponding leak point on the sensing cable; The determination of the target input current and target voltage range of the sensing cable based on the first voltage signal includes: Calculate the second impedance value of the sensing cable based on the first voltage signal and the safe initial current; Based on the impedance range in which the second impedance value is located, determine the target input current and target voltage range corresponding to the sensing cable; The distributed resistance model includes: ； in, The first impedance value; ; ; The resistance per unit length of the sensing cable; The distance from the measuring end to the leak point; The matching resistor is the one to which the sensing cable is connected; The impedance at the leakage point; The location of the leak point corresponding to the first impedance value is determined based on the distributed resistance model, including: Determine the first current value and the second current value based on the target input current; Obtain the first equivalent impedance value corresponding to the first current value, and the second equivalent impedance value corresponding to the second current value; The first current value, the first equivalent impedance value, the second current value, and the second equivalent impedance value are respectively input into the distributed resistance model to solve the impedance of the leak point and the distance from the measuring end to the leak point, so as to obtain the leak point location result.

2. The leakage detection and location method applied to environmental monitoring according to claim 1, characterized in that, Determining the target input current and target voltage range corresponding to the sensing cable includes: Query the target input current and target voltage range corresponding to the impedance range in the adaptive decision table; or, Based on the preset decision logic function, the target input current and target voltage range corresponding to the impedance range are obtained.

3. The leakage detection and location method applied to environmental monitoring according to claim 1, characterized in that, The location of the leak point corresponding to the first impedance value is determined based on the distributed resistance model, including: Based on the distributed resistance model, a two-dimensional relationship table is calibrated to represent the relationship between impedance value, distance from the measuring end to the leak point, and impedance at the leak point. Based on the two-dimensional relationship table, the distance from the measuring end corresponding to the first impedance value to the leak point is determined, and the leak point location result is obtained.

4. The method for leak detection and location applied to environmental monitoring according to any one of claims 1 to 3, characterized in that, The method further includes: In response to the activation of the continuous monitoring mode, the step of inputting a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range is performed at a preset period.

5. The method for leak detection and location applied to environmental monitoring according to any one of claims 1 to 3, characterized in that, After calculating the first impedance value of the sensing cable based on the second voltage signal, the method further includes: Obtain the third impedance value of the sensing cable in the previous cycle; If the change in the first impedance value compared to the third impedance value exceeds a preset threshold, then the step of inputting a safe initial current into the sensing cable to obtain the first voltage signal at both ends of the sensing cable within a preset voltage range is executed.

6. A leakage detection and location device for environmental monitoring, characterized in that, include: A programmable excitation module, connected to the sensing cable, is used to input excitation current into the sensing cable; A configurable acquisition module is connected to the sensing cable and is used to acquire the voltage signals at both ends of the sensing cable when an excitation current is input to the sensing cable. The microcontroller unit is communicatively connected to the programmable excitation module and the configurable acquisition module, and is used to execute the leakage detection and location method for environmental monitoring as described in any one of claims 1 to 5.

7. A leakage detection and location device for environmental monitoring according to claim 6, characterized in that, The microcontroller unit includes a memory, which stores an adaptive decision table or a decision logic function. The memory also stores a distributed resistance model and / or a two-dimensional relationship table representing the relationship between impedance value, distance from the measuring end to the leak point, and impedance of the leak point.

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