A method and apparatus for detecting water leaks based on a conductive sensing cable

Abstract

This invention discloses a method and apparatus for leak detection based on a conductive induction cable, comprising: laying a conductive induction cable containing two mutually insulated conductive cores at the lowest water accumulation point in the monitoring area; connecting the two conductive cores to a detection circuit, the detection circuit including a voltage divider resistor network and a switching device; converting the resistance change between the two conductive cores into a voltage change at the detection node through the voltage divider resistor network; the switching device switching between a first switching state and a second switching state according to the change in the voltage at the detection node relative to its conduction threshold, and outputting a corresponding switching signal; and a control unit reading the level state of the switching signal to distinguish between a waterless state and a leaking state. This invention also provides a corresponding leak detection device. The circuit structure of this invention is simple, low-cost, flexible in deployment, and has a fast response speed, enabling rapid identification of minute leaks and accumulations, and its sensitivity is adjustable to adapt to different water qualities.

Description

Technical Field

[0001] This invention relates to the field of water leakage detection technology, and in particular to a method and apparatus for water leakage detection using a conductive induction cable in conjunction with a switching circuit. Background Technology

[0002] In industrial applications such as underwater robots, diving equipment, and others requiring leak monitoring of sealed cavities, seals may fail during operation due to aging of seals, mechanical impacts, or material fatigue, allowing external liquids to seep into the internal cavities. Failure to detect and address leaks promptly can lead to short circuits in electronic components, corrosion of mechanical parts, and even complete equipment failure, resulting in significant economic losses and safety incidents. Therefore, deploying leak detection devices at critical low-lying locations within the equipment to quickly identify and alarm on leaks is crucial for ensuring safe equipment operation.

[0003] Currently, common leak detection solutions in existing technologies mainly include the following categories:

[0004] (1) Humidity sensor-based detection scheme: Deploy humidity sensors in the monitoring area to indirectly determine whether there is water leakage by detecting changes in the relative humidity of the environment. The drawbacks of this scheme are: the humidity sensor can only be triggered after the ambient humidity accumulates to a certain threshold, resulting in a long response time; when there are natural humidity fluctuations in the monitoring area (such as condensation caused by temperature changes during equipment operation), false alarms are likely to occur; and the humidity sensor cannot directly detect the presence of liquid water, so the reliability of the detection is not high.

[0005] (2) Detection scheme based on float switch: A float switch is installed at the bottom of the equipment. When the water level rises to a certain height, the float rises and triggers the switch. The main problems with this scheme are: the float switch is large in size and requires a lot of installation space, making it difficult to deploy in a small cavity; it requires the water to reach a certain depth to trigger, and it is not sensitive to small leaks; the mechanical moving parts are at risk of jamming and failure after long-term use, which limits the reliability.

[0006] (3) Detection scheme based on pressure sensor: Install a pressure sensor at the bottom of the sealed cavity and determine leakage by detecting the change in the static pressure of the liquid at the bottom of the cavity. This scheme is costly, the accuracy of the pressure sensor is sensitive to temperature changes and temperature compensation is required; in addition, the sensor needs to be in direct contact with the liquid being measured, which requires a high level of protection for the sensor itself, and the accuracy drifts significantly after long-term immersion.

[0007] (4) Electrode probe-based detection scheme: Two metal probes are placed at the monitoring point, and the leakage is determined by the liquid conducting the circuit between the two probes. The drawback of this scheme is that the probes are point sensors, which can only detect the water accumulation at the location of the probes, and the detection coverage area is small; if the water accumulation does not exactly submerge the two probes, the detection cannot be triggered, and false alarms are likely to occur.

[0008] In summary, existing leak detection solutions generally suffer from high costs, poor deployment flexibility, insensitivity to small leaks, and limited detection coverage, making them unsuitable for applications such as underwater robots that require compact space, low cost, high reliability, and rapid response. Therefore, there is an urgent need for a leak detection solution that is low-cost, flexible in deployment, fast in response, and highly reliable. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method and apparatus for detecting water leakage based on conductive induction cables.

[0010] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0011] A water leakage detection method based on conductive induction cables includes the following steps:

[0012] Step S1: Lay a conductive induction cable at the lowest water accumulation point in the monitoring area. The conductive induction cable consists of two mutually insulated conductive core wires.

[0013] Step S2: Connect the two conductive cores of the conductive sensing cable to the first input terminal and the second input terminal of the detection circuit, respectively. The detection circuit includes a voltage divider resistor network and a switching device.

[0014] Step S3: The resistance change between the two conductive core wires is converted into a voltage change at the detection node through the voltage divider resistor network;

[0015] Step S4: Receive the voltage of the detection node through the control terminal of the switching device, and the switching device switches between a first switching state and a second switching state according to the change of the voltage of the detection node relative to its conduction threshold.

[0016] Step S5: Output a switching signal corresponding to the first switching state or the second switching state through the output terminal of the switching device, wherein the first switching state corresponds to a water leakage state in which the two conductive cores are connected by liquid, and the second switching state corresponds to a waterless state in which the two conductive cores are not connected by liquid, or vice versa.

[0017] Step S6: The control unit reads the level of the switch signal to distinguish between the waterless state and the water leakage state.

[0018] Furthermore, the conductive sensing cable is a water leakage detection rope, which is made of two insulated conductive strands wound together, and is flexible, bendable, and cuttable.

[0019] Furthermore, the conductive sensing cable is a water leakage detection strip, which has a flat strip structure and conductive metal strips are segmented on its surface to increase the contact area with accumulated water.

[0020] Furthermore, the voltage divider resistor network includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the power supply terminal VCC, and the second end is connected to the first conductive core wire Water1 of the conductive sensing cable to form a detection node TP1. The first end of the fourth resistor R4 is connected to the detection node TP1, and the second end is grounded. The second conductive core wire Water2 of the conductive sensing cable is grounded.

[0021] Furthermore, the detection circuit also includes a first resistor R1, which is connected between the signal terminal TP2 and the control terminal of the switching device for current limiting and impedance matching, wherein the signal terminal TP2 is the output terminal of the voltage of the detection node after passing through the voltage divider resistor network.

[0022] Furthermore, the switching device is a MOS transistor U1, the gate of which is connected to the signal terminal TP2, the source is grounded, and the drain is connected to the detection node TP1.

[0023] This invention also discloses a water leakage detection device based on a conductive induction cable, comprising:

[0024] The conductive sensing cable consists of two mutually insulated conductive core wires and is laid at the lowest water accumulation point in the monitoring area.

[0025] The detection circuit includes a voltage divider resistor network, a switching device, a first connector J1, and a second connector J2. The first connector J1 is used to connect the power supply terminal VCC, the ground terminal GND, and the signal terminal TP2. The second connector J2 is used to connect the two conductive cores of the conductive sensing cable. The voltage divider resistor network includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the power supply terminal VCC, and the second end is connected to the first conductive core Water1 of the conductive sensing cable to form a detection node TP1. The first end of the fourth resistor R4 is connected to the detection node TP1, and the second end is grounded. The second conductive core Water2 of the conductive sensing cable is grounded. The control terminal of the switching device U1 is connected to the signal terminal TP2, the output terminal is connected to the detection node TP1, and the low potential terminal is grounded. It is used to switch the switching state and output a switching signal according to the voltage state of the detection node TP1 or the signal terminal TP2.

[0026] The control unit is connected to the output terminal of the switching device and is used to read the level state of the switching signal to distinguish between the waterless state and the water leakage state.

[0027] Furthermore, the detection circuit also includes a first resistor R1, which is connected between the signal terminal TP2 and the control terminal of the switching device.

[0028] Furthermore, the switching device is a MOSFET, a voltage comparator, or a bipolar transistor.

[0029] Furthermore, the conductive sensing cable is a leak detection rope or a leak detection strip; the leak detection rope is made of two insulated conductive strands wound together, and the leak detection strip is a flat strip structure with conductive metal strips segmented on its surface.

[0030] Compared with the prior art, the advantages of the present invention are as follows:

[0031] (1) The circuit structure is simple and the cost is low: the detection circuit consists of only basic resistors, MOSFETs and terminals. All components are general standard parts, and the circuit material cost is extremely low. The detection circuit directly outputs standard switching signals. The control unit does not need to perform analog signal conditioning and analog-to-digital conversion. The software logic is lightweight, which further reduces the overall system cost.

[0032] (2) Flexible deployment and strong adaptability: The conductive induction cable (leakage detection rope / belt) can be freely cut to the appropriate length according to the size and shape of the monitoring area. It can be laid along narrow areas such as pipes and cable trays, or it can cover a large area in a flat area. The detection circuit can be integrated into the main control circuit board of the equipment, or it can be made into an independent standardized leak detection module for separate use to meet the integration needs of different equipment.

[0033] (3) Fast response speed and sensitive to small leaks: The conductive induction cable is a linear or strip sensor. As long as the water touches any part of the cable, the detection will be triggered. The detection coverage is much larger than that of a point sensor. Once the water submerges or soaks the surface of the cable, the two conductive core wires will immediately conduct. The circuit response time is only limited by the switching speed of the MOSFET (usually in the microsecond range), which can realize the rapid identification of small leaks of water.

[0034] (4) Adjustable sensitivity to adapt to different water qualities: By adjusting the resistance value of the voltage divider resistor network in the detection circuit, the response sensitivity of the switching device to the change of resistance of the conductive sensing cable can be changed, thereby adapting to water qualities with different conductivity (such as fresh water, seawater, industrial wastewater containing impurities, etc.), without the need to replace the sensor for different water qualities.

[0035] (5) This invention can be widely applied to underwater robots, diving equipment, industrial sealed cavities, machine room pipelines, pipelines and other scenarios that require real-time monitoring of water accumulation or leakage. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the water leakage detection method provided in an embodiment of the present invention;

[0038] Figure 2 This is a system structure block diagram of the water leakage detection device provided in an embodiment of the present invention;

[0039] Figure 3 The circuit diagram is shown for the core detection circuit provided in the embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment provides a water leakage detection method based on conductive induction cables. For example... Figure 1 As shown, the method includes the following steps:

[0043] Step S1: Lay conductive induction cables.

[0044] A conductive sensing cable 100 is laid at the lowest water accumulation point in the monitoring area. The conductive sensing cable 100 consists of two mutually insulated conductive cores (Water1, Water2). Under normal dry conditions, the two conductive cores are insulated from each other, and the equivalent resistance Rx between them is extremely high, typically above the megaohm level.

[0045] The specific selection of the conductive induction cable 100 can be determined based on the spatial shape and size of the monitoring area:

[0046] For narrow, elongated areas (such as the bottom of server racks, cable trays, and along pipes), a leak detection rope is preferred. This detection rope is made of two insulated conductive strands wound together, has high flexibility, and can be bent and cut to the required length at will.

[0047] For flat areas (such as computer room floors, rack undersides, and large platforms), leak detection strips are preferred. These strips have a flat, strip-like structure with conductive metal strips segmented on their surface, resulting in a larger contact area with accumulated water and a faster response to water accumulation.

[0048] During installation, ensure the cable is laid flat against the ground or equipment base surface, avoiding suspension or elevation to prevent small amounts of water from failing to reach the conductive core wires and causing missed detections. For scenarios where the equipment may tilt or shift during operation (such as underwater robots operating in complex terrain), the detection cable should be laid in sections at all possible low points of the equipment to prevent a single detection point from failing to cover the leaking area due to changes in equipment posture.

[0049] Step S2: Connect the conductive sensing cable to the detection circuit.

[0050] The two conductive cores of the conductive sensing cable 100 are respectively connected to the first input terminal and the second input terminal of the detection circuit 200. The connection between the detection circuit 200 and the conductive sensing cable 100 can be achieved through terminal blocks, which facilitates on-site installation and replacement.

[0051] Step S3: The change in resistance is converted into a change in voltage.

[0052] like Figure 3 As shown, the detection circuit includes a voltage divider resistor network, a switching device U1, a first connector J1, and a second connector J2. The first connector J1 connects to the power supply terminal VCC, the ground terminal GND, and the signal terminal TP2; the second connector J2 connects to the first conductive core wire Water1 and the second conductive core wire Water2 of the conductive sensing cable 100. The voltage divider resistor network includes a third resistor R3 and a fourth resistor R4. The first end of R3 is connected to the power supply terminal VCC, and the second end is connected to the first conductive core wire Water1, forming a detection node TP1; the first end of R4 is connected to the detection node TP1, and the second end is grounded to GND; the second conductive core wire Water2 is also grounded to GND.

[0053] Under normal, waterless conditions, the equivalent resistance Rx between the two core wires of the conductive sensing cable 100 is extremely high (close to an open circuit). At this time, the voltage at the detection node TP1 is determined by the voltage division of R3 and R4, approximately VCC*R4 / (R3+R4). When water leakage occurs, the liquid submerges or soaks the surface of the conductive sensing cable 100. The conductivity of water causes continuity between the two core wires, resulting in a significant drop in the equivalent resistance Rx. Since Rx is connected in parallel with R4, the reduced equivalent resistance causes the voltage at the detection node TP1 to drop accordingly.

[0054] Step S4: Switching the state of the switching device.

[0055] The control terminal (gate) of the switching device U1 is connected to the signal terminal TP2 through the first resistor R1, the output terminal (drain) is connected to the detection node TP1, and the low-potential terminal (source) is grounded to GND. In this embodiment, the switching device U1 is preferably an N-channel enhancement-mode MOS transistor.

[0056] Its working principle is as follows:

[0057] In the waterless state: the equivalent resistance Rx of the conductive sensing cable is extremely high, and the voltage at the detection node TP1 is high. This voltage is applied to the gate of the MOSFET U1 through R1. When the gate voltage is higher than its turn-on threshold voltage Vgs(th), U1 turns on. After U1 turns on, its drain (i.e., the detection node TP1) is pulled low to a level close to GND.

[0058] Leakage condition: Liquid conducts through the core wire, Rx drops significantly, and the voltage at the detection node TP1 drops. When this voltage is lower than Vgs(th) of MOSFET U1, U1 is turned off. After U1 is turned off, its drain (i.e., the detection node TP1) is pulled up to a high level close to VCC by a pull-up resistor (not shown in the figure, or R3 can be used as it).

[0059] Therefore, the level of the detection node TP1 or signal terminal TP2 indicates whether there is a leak. It should be noted that, depending on the type of MOSFET used (N-channel / P-channel) and the circuit topology, the output levels corresponding to no water / leaking can be interchanged, as long as the control unit can distinguish between the two states. The above correspondence does not constitute a limitation on the protection range.

[0060] Step S5: Current limiting and voltage division adjustment.

[0061] The first resistor R1 is connected in series between the signal terminal TP2 and the gate of the MOSFET U1, which serves as a current limiting protection. At the same time, it forms an RC low-pass filter with the gate input capacitor, which can effectively suppress high-frequency noise interference.

[0062] The third resistor R3 and the fourth resistor R4 form a voltage divider network. By adjusting the resistance ratio of R3 and R4, the reference voltage of the detection node TP1 in the waterless state can be set, thereby adjusting the detection sensitivity.

[0063] When R3 is large or R4 is small, the TP1 voltage is low in the waterless state, the water resistance threshold required to trigger leakage is small, and the detection sensitivity is high.

[0064] Conversely, when R3 is small or R4 is large, TP1 voltage is high in the waterless state, trigger threshold is large, and sensitivity is low.

[0065] This design allows the invention to adapt to water qualities with varying conductivity. For example, for pure water with low conductivity, the equivalent resistance Rx remains relatively large after conduction, so R4 can be appropriately reduced or R3 increased to improve sensitivity. For seawater with high conductivity, the equivalent resistance Rx is extremely small after conduction, so R4 can be appropriately increased or R3 decreased to avoid false triggering caused by noise interference. The values ​​of R3 and R4 can be selected as needed, ranging from hundreds of ohms to hundreds of kiloohms.

[0066] Step S6: The control unit reads the signal.

[0067] The general purpose input / output (GPIO) pins of the control unit 300 (such as an MCU microcontroller) are connected to the signal output terminal TP2. The water level and leakage status can be distinguished by reading the level of TP2. Since the detection circuit 200 directly outputs a standard switching signal (high or low level), the control unit 300 does not need to perform analog signal conditioning or analog-to-digital conversion; it only needs to perform a simple digital level reading operation to complete the leakage determination. After detecting a leakage, the control unit 300 can perform corresponding actions according to a preset strategy, including but not limited to: issuing an audible and visual alarm signal, sending an alarm message to the host computer, cutting off the main power supply to the equipment, starting the drain pump, and recording the leakage event log.

[0068] Example 2

[0069] This embodiment provides a water leakage detection device based on a conductive induction cable. For example... Figure 2 As shown, the device includes a conductive sensing cable 100, a detection circuit 200, and a control unit 300.

[0070] Conductive induction cable 100: Composed of two mutually insulated conductive core wires, laid at the lowest water accumulation point in the monitoring area. Its specific structure and selection have been detailed in Example 1 and will not be repeated here.

[0071] Detection circuit 200: includes a voltage divider resistor network, a switching device U1, a first connector J1, and a second connector J2 (see...) Figure 3The first connector J1 is used to connect the power supply terminal VCC, the ground terminal GND, and the signal terminal TP2; the second connector J2 is used to connect the first conductive core wire Water1 and the second conductive core wire Water2 of the conductive induction cable 100. The voltage divider resistor network includes a third resistor R3 and a fourth resistor R4, the connection method and function of which have been detailed in Embodiment 1. The switching device is a MOSFET U1, the connection method and function of which have also been explained above.

[0072] The detection circuit 200 can be deployed in one of the following two ways:

[0073] 1. Integrated Deployment: The components of the detection circuit 200 are directly laid out on the main control circuit board of the device, sharing power and ground with the main control system. The signal output terminal TP2 is connected to the GPIO pin of the main control MCU through PCB traces. This method is suitable for planning the water leakage detection function as part of the system functionality in the early stages of device design.

[0074] 2. Modular Deployment: The components of the detection circuit 200 are laid out on an independent printed circuit board to create a standardized leak detection module, providing power input interfaces (VCC and GND), cable connection interfaces (Water1 and Water2), and signal output interfaces (TP2). This method is suitable for retrofitting existing equipment with leak detection functionality or for supplying it as an independent module to third-party equipment integrators.

[0075] Control unit 300: Connected to the signal output terminal TP2 of detection circuit 200, used to read the level state of switch signals. Control unit 300 can be a controller with digital input function, such as a microcontroller (MCU), digital signal processor (DSP), field-programmable gate array (FPGA), or embedded processor. The GPIO pins of control unit 300 are directly connected to TP2, eliminating the need for an external analog-to-digital converter.

[0076] Taking the sealed cavity of an underwater robot as an example, the deployment method is explained as follows: A conductive induction cable 100 is laid at the lowest point of the sealed cavity, following the contour of the cavity's bottom to ensure that water first contacts the cable under gravity. For cases where there are multiple potential water-accumulating points at the bottom of the cavity, a segmented laying method can be used, deploying multiple segments of the conductive induction cable at each low point and connecting these segments in parallel to the input of the same detection circuit 200 to ensure that any leak can be detected. The detection circuit 200 and control unit 300 are installed in the dry area within the sealed cavity. The conductive induction cable 100 is connected to the detection circuit 200 via waterproof terminals.

[0077] Example 3

[0078] This embodiment provides several alternative solutions for the switching device to demonstrate the universality of the technical solution of the present invention.

[0079] Alternative Option 1: Use a P-channel MOSFET.

[0080] The source of the P-channel MOSFET is connected to VCC, the drain is connected to GND via a pull-down resistor and serves as the signal output terminal, and the gate is connected to the detection node TP1 via a current-limiting resistor. Accordingly, the output level polarity corresponding to no water / leaking water will be the opposite of that in Example 1 (high level output when no water, low level output when leaking water). The control unit can make corresponding logic adjustments when making level judgments.

[0081] Alternative solution 2: Use a voltage comparator.

[0082] The voltage at detection node TP1 is input to the non-inverting (or inverting) input of a voltage comparator, and the other input of the comparator is connected to a preset reference voltage Vref. When the voltage at TP1 is higher than Vref, the comparator outputs a first level; when the voltage at TP1 is lower than Vref, the comparator outputs a second level. By adjusting the reference voltage Vref, the trigger threshold for leak detection can be precisely set, achieving more flexible and precise threshold control than the MOSFET solution.

[0083] Alternative Option 3: Use a bipolar junction transistor (BJT).

[0084] Replacing the N-channel MOSFET with an NPN transistor, a current-limiting resistor is connected in series with the base of the transistor and then connected to the detection node TP1. The emitter is grounded, and the collector is connected to VCC via a pull-up resistor and serves as the signal output. The transistor solution has lower material costs, but its input impedance is lower than that of the MOSFET, making it suitable for scenarios where power consumption requirements are not high.

[0085] Example 4

[0086] This embodiment illustrates an alternative to the voltage divider resistor network. Besides changing the reference voltage and sensitivity of the detection node TP1 by adjusting the resistance values ​​of the third resistor R3 and the fourth resistor R4, the voltage variation amplitude of the detection node TP1 can also be changed by adjusting the resistance value of the second resistor R2. Furthermore, the circuit parameters described in the above embodiments (such as the resistance values ​​of R1, R2, R3, and R4, the VCC supply voltage, etc.) are all design variables that can be adjusted according to actual application requirements. Those skilled in the art can determine appropriate parameter values ​​through conventional circuit calculations based on the characteristics of the selected MOSFET, the supply voltage level, the specifications of the conductive sensing cable, and the target water quality conditions. The specific values ​​of these parameters do not constitute a limitation on the scope of protection of this invention.

[0087] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A water leakage detection method based on conductive induction cables, characterized in that, Includes the following steps: Step S1: Lay a conductive induction cable at the lowest water accumulation point in the monitoring area. The conductive induction cable consists of two mutually insulated conductive core wires. Step S2: Connect the two conductive cores of the conductive sensing cable to the first input terminal and the second input terminal of the detection circuit, respectively. The detection circuit includes a voltage divider resistor network and a switching device. Step S3: The resistance change between the two conductive core wires is converted into a voltage change at the detection node through the voltage divider resistor network; Step S4: Receive the voltage of the detection node through the control terminal of the switching device, and the switching device switches between a first switching state and a second switching state according to the change of the voltage of the detection node relative to its conduction threshold. Step S5: Output a switching signal corresponding to the first switching state or the second switching state through the output terminal of the switching device, wherein the first switching state corresponds to a water leakage state in which the two conductive cores are connected by liquid, and the second switching state corresponds to a waterless state in which the two conductive cores are not connected by liquid, or vice versa. Step S6: The control unit reads the level of the switch signal to distinguish between the waterless state and the water leakage state.

2. The leakage detection method according to claim 1, characterized in that, The conductive sensing cable is a water leakage detection rope, which is made of two insulated conductive strands wound together.

3. The leakage detection method according to claim 1, characterized in that, The conductive sensing cable is a water leakage detection strip, which has a flat strip structure and conductive metal strips are segmented on its surface.

4. The leakage detection method according to claim 1, characterized in that, The voltage divider resistor network includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the power supply terminal VCC, and the second end is connected to the first conductive core wire Water1 of the conductive sensing cable to form a detection node TP1. The first end of the fourth resistor R4 is connected to the detection node TP1, and the second end is grounded. The second conductive core wire Water2 of the conductive sensing cable is grounded.

5. The leakage detection method according to claim 4, characterized in that, The detection circuit further includes a first resistor R1, which is connected between the signal terminal TP2 and the control terminal of the switching device for current limiting and impedance matching. The signal terminal TP2 is the output terminal of the voltage of the detection node after passing through the voltage divider resistor network.

6. The leakage detection method according to claim 4, characterized in that, The switching device is a MOS transistor U1, with its gate connected to the signal terminal TP2, its source grounded, and its drain connected to the detection node TP1.

7. A water leakage detection device based on a conductive induction cable, characterized in that, include: The conductive sensing cable consists of two mutually insulated conductive core wires and is laid at the lowest water accumulation point in the monitoring area. The detection circuit includes a voltage divider resistor network, a switching device, a first connector J1, and a second connector J2. The first connector J1 is used to connect the power supply terminal VCC, the ground terminal GND, and the signal terminal TP2. The second connector J2 is used to connect the two conductive cores of the conductive sensing cable. The voltage divider resistor network includes a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 is connected to the power supply terminal VCC, and the second end is connected to the first conductive core Water1 of the conductive sensing cable to form a detection node TP1. The first end of the fourth resistor R4 is connected to the detection node TP1, and the second end is grounded. The second conductive core Water2 of the conductive sensing cable is grounded. The control terminal of the switching device U1 is connected to the signal terminal TP2, the output terminal is connected to the detection node TP1, and the low potential terminal is grounded. It is used to switch the switching state and output a switching signal according to the voltage state of the detection node TP1 or the signal terminal TP2. The control unit is connected to the output terminal of the switching device and is used to read the level state of the switching signal to distinguish between the waterless state and the water leakage state.

8. The leakage detection device according to claim 7, characterized in that, The detection circuit further includes a first resistor R1, which is connected between the signal terminal TP2 and the control terminal of the switching device.

9. The leakage detection device according to claim 7, characterized in that, The switching device is a MOSFET, a voltage comparator, or a bipolar transistor.

10. The leakage detection device according to claim 7, characterized in that, The conductive sensing cable is a leak detection rope or a leak detection strip; the leak detection rope is made of two insulated conductive strands wound together, and the leak detection strip is a flat strip structure with conductive metal strips segmented on its surface.

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