Liquid leak detection system and method

Abstract

This invention provides a liquid leak detection system, including a host computer and detection nodes that are communicatively and electrically connected to the host computer. The host computer sends instructions to the detection nodes and receives detection data transmitted by the detection nodes. Each detection node includes a control system and detection lines; the detection lines include five cables arranged in parallel: the first and second cables are power lines used to supply power to the detection nodes and transmit data; the third cable is a detection wire with a braided sheath; the fourth cable is a rubber conductor with resistance; and the fifth cable is an insulated conductor. The control system includes a controller, a constant current source unit, and a constant voltage source unit electrically connected to the controller. The constant current source unit and the constant voltage source unit can be switched arbitrarily to achieve different detection functions. The liquid leak detection system and method provided by this invention have a simple system structure, long detection distance, high accuracy, and can simultaneously detect multiple areas.

Description

Technical Field

[0001] This invention relates to the field of liquid leak detection technology, and in particular to a liquid leak detection system and method. Background Technology

[0002] In recent years, leakage accidents of liquid transportation pipelines have occurred frequently in my country. Liquid transportation pipelines are generally installed underground or in relatively concealed locations. Once a pipeline leaks or is damaged, it cannot be detected and judged in a timely and accurate manner, resulting in huge economic losses and environmental pollution. Therefore, it is very necessary to study the real-time detection and leak location of liquid transportation pipelines.

[0003] Current conventional detection techniques for handling liquid leaks involve installing detection lines around the liquid transmission pipeline and determining the extent of the leak based on the voltage detected by the lines. In the long term, the pipeline leak monitoring industry needs more reliable and effective technologies to ensure the real-time performance, accuracy, and effectiveness of leak monitoring, as well as high location precision and low false alarm rates. Based on these capabilities, wider-range, multi-area leak detection can be achieved to meet the growing demands of society.

[0004] Existing leak detection devices use a four-core wire for the detection line, consisting of two detection lines and two ordinary lines, arranged in a cross pattern. A switch controlled by a microprocessor outputs a control signal to change the connection type of the detection line. Current is applied to the detection line to measure the voltage at a specific location to check for and determine the location of a leak. When a leak occurs, the voltage at the specific node is the same as the voltage at the leak point; when no leak occurs, the voltage at the specific node is 0.

[0005] Existing detection pipelines often use four-core wires, with connection status controlled by switches, increasing manufacturing costs and impacting the efficiency of the detection device. Furthermore, their detection distance is insufficient, limiting detection to a single leak point and preventing the detection of multiple leaks across multiple areas. They lack open-circuit detection capabilities; when a leak occurs, the voltage at that specific node drops to zero, mirroring the absence of a leak, making it impossible to clearly distinguish between an open circuit and the absence of a leak. Moreover, open-circuit faults cannot be detected promptly, and in the event of a leak, the device is unable to perform detection, potentially leading to inaccurate results. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a liquid leak detection system and method to solve problems such as short detection distance and low efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A liquid leak detection system includes a host computer and detection nodes that communicate with and are electrically connected to the host computer.

[0009] The host is used to send instructions to the detection node and receive detection data transmitted by the detection node;

[0010] The detection node includes a control system and a detection circuit. The detection circuit includes five cables arranged in parallel. The first and second cables are power lines used to supply power to the detection node and transmit data. The third cable is a detection cable with a braided sheath. The fourth cable is a rubber conductor with resistance. The fifth cable is an insulated conductor. The control system includes a controller, a constant current source unit, and a constant voltage source unit electrically connected to the controller. The first end of the third cable is connected to the constant current source unit. The first end of the fourth cable is connected to the constant voltage source unit. The second end of the fourth cable is connected to the second end of the fifth cable, and the first end of the fifth cable is connected to ground after being connected in series with a reference resistor. The first ends of the first and second cables are electrically connected to the controller. The second ends of the first and second cables are electrically connected to the main unit.

[0011] Further improvements to the above technical solution are:

[0012] The liquid leak detection system includes at least two detection nodes; the second ends of the first cable and the second cable of each detection node are electrically connected to the controller of the previous detection node, respectively.

[0013] The controller includes a voltage acquisition module, which is used to acquire the voltage value of the detection line.

[0014] The constant current source unit includes a transistor and a constant current source electrically connected to the collector of the transistor; the emitter of the transistor is electrically connected to the first end of the third cable, and the base of the transistor is electrically connected to the controller.

[0015] The constant voltage source unit includes an optocoupler, a fixed resistor connected in series between the optocoupler and the controller, and a constant voltage source electrically connected to the collector of the optocoupler; the emitter of the optocoupler is electrically connected to the first end of the fourth cable.

[0016] The host includes a processor and a power line carrier module electrically connected to the processor.

[0017] The present invention also provides a liquid leak detection method for use in the above-mentioned liquid leak detection system, comprising the following steps:

[0018] The first end of the third cable is connected to the control system, and the first end of the fourth cable is disconnected from the control system;

[0019] Obtain the voltage value U11 at the first end of the fourth cable; obtain the voltage value U12 at the first end of the fifth cable;

[0020] If U11 and U12 are both zero, it is determined that there is no liquid leakage; if U11 and U12 are not both zero, it is determined that there is a liquid leakage.

[0021] When a liquid leak is detected, the location of the leak point is calculated. The specific calculation method is as follows: calculate the ratio of the voltage value U12 at the first end of the fifth cable to the resistance value R of the reference resistor to obtain the current value I1 in the circuit at this time; calculate the resistance value R4 of the fourth cable in the circuit at this time based on the voltage value U12 at the first end of the fifth cable, the voltage value U11 at the first end of the fourth cable, and the current value I1; calculate the ratio of the resistance value R4 to the resistivity of the fourth cable to obtain the distance d between the leak point and the starting point of the second end of the fourth cable.

[0022] Furthermore, it also includes a wire breakage detection step:

[0023] The first end of the fourth cable is connected to the control system, and the first end of the third cable is disconnected from the control system.

[0024] Obtain the voltage value U2 at the first end of the fifth cable;

[0025] If U2 is zero, it indicates a disconnection; if U2 is not zero, it indicates the line is normal.

[0026] Furthermore, it also includes a total cable length detection step:

[0027] The first end of the fourth cable is connected to the control system, and the first end of the third cable is disconnected from the control system.

[0028] Obtain the voltage value U1 at the first end of the fourth cable; obtain the voltage value U2 at the first end of the fifth cable;

[0029] Calculate the ratio of the voltage value U2 at the first end of the fifth cable to the resistance value R of the reference resistor to obtain the current value I2 in the circuit at this time; calculate the resistance value R5 of the fifth cable in the circuit at this time based on the voltage value U2 at the first end of the fifth cable, the voltage value U1 at the first end of the fourth cable, and the current value I2; calculate the ratio of the resistance value R5 to the resistivity of the fifth cable to obtain the total length L of the fifth cable.

[0030] Furthermore, the liquid leak detection system includes at least two detection nodes; the second ends of the first cable and the second cable of each detection node are electrically connected to the controller of the previous detection node, respectively.

[0031] The first end of the third cable of each detection node is connected to the corresponding control system, and the first end of the fourth cable of each detection node is disconnected from the corresponding control system.

[0032] The voltage value U11 of the first end of the fourth cable of each detection node is obtained; the voltage value U12 of the first end of the fifth cable of each detection node is obtained.

[0033] If U11 and U12 of the detection node are zero, it is determined that there is no liquid leakage at the detection node; if U11 and U12 of the detection node are not zero, it is determined that there is liquid leakage at the detection node.

[0034] When a detection node determines that a liquid leak has occurred, the location of the leak point of the detection node is calculated to obtain the distance between the leak point of the detection node and the starting point of the second end of the fourth cable of the detection node.

[0035] According to the technical solution of this invention, the liquid leak detection system includes a host and detection nodes. The detection nodes use two power lines as data transmission lines. The system structure is simple, low-cost, economical, reliable, and easily implements long-distance communication. Its detection lines include five cables: the first and second cables are used for power supply and data transmission; the fourth and fifth cables, when connected to the control system, can be used to detect whether a line break has occurred; the third cable, when connected to the control system, can be used to detect whether a liquid leak has occurred. Based on the detection data received from the detection nodes, the host can further calculate the location of the leak point and the total length of the detection lines. The liquid leak detection system and detection method of this invention are very simple. It only needs to obtain the voltage values ​​at the first ends of the fourth and fifth cables to calculate the location information of the leak point, resulting in accurate results and high system efficiency. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the liquid leak detection system according to Embodiment 2 of the present invention.

[0037] Figure 2 This is a schematic diagram of the detection node of the liquid leakage detection system according to an embodiment of the present invention.

[0038] Figure 3 This is a schematic diagram of the circuit connection during the wire breakage detection of the liquid leakage detection method according to an embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the circuit connection during leakage detection in the liquid leakage detection method of this invention.

[0040] Figure 5 This is a circuit connection diagram for detecting the total cable length in the liquid leakage detection method of this invention.

[0041] Figure 6 This is a schematic diagram of data transmission in the liquid leak detection system of Embodiment 2 of the present invention.

[0042] Figure 7 This is a schematic flowchart of a liquid leak detection method according to an embodiment of the present invention. Detailed Implementation

[0043] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0045] Example 1: As Figures 1 to 6 As shown, the liquid leak detection system of this embodiment includes a host and a detection node that communicates with and is electrically connected to the host.

[0046] like Figure 1 and Figure 6 As shown, the host computer is used to send instructions to the detection node and receive detection information transmitted by the detection node. The host computer includes a processor (MCU) and a power line carrier module electrically connected to the processor (MCU). The power line carrier module is used to receive instruction information sent by the processor, convert it, and send it to the detection node; and to receive detection information transmitted by the detection node, convert it, and send it to the processor. The detection node is communicatively connected to the power line carrier module via a first cable and a second cable.

[0047] like Figure 2As shown, the detection node includes a control system and a detection circuit. The detection circuit includes five cables arranged in parallel. The first cable 1 and the second cable 2 are power lines used to power the detection node and transmit data. The first cable 1 and the second cable 2 use power line carrier communication as the data transmission method. The principle is to apply a high-frequency signal carrying information to the power line for data transmission, and then separate the high-frequency signal of the power line channel through power line modulation and demodulation before transmitting it. In this embodiment, VCC and GND power lines are used as the first cable 1 and the second cable 2 for data transmission, and a power line carrier module is embedded in the detection node. The third cable 3 in this embodiment is a conductor with a braided sheath. When there is no liquid leakage, the braided sheath has good insulation properties; when there is a liquid leakage, the liquid can conduct with the conductor inside the braided sheath to form a circuit. The fourth cable 4 in this embodiment is a conductor with a fixed resistor connected in series, and the conductor of the fourth cable 4 is covered with conductive rubber. The fifth cable 5 is an ordinary insulated conductor. In this embodiment, the end of the detection line closer to the control system is defined as the first end, and the end farther from the control system is defined as the second end. The fourth cable 4 is connected in series with a fixed resistor, which can compensate for the measured voltage, increase the voltage value at the test point, and thus improve the accuracy of leak detection and location.

[0048] like Figure 2 As shown, the control system in this embodiment includes a controller MCU, a constant current source unit and a constant voltage source unit electrically connected to the controller, and a power line carrier module for transmitting and converting data.

[0049] The constant current source unit includes a transistor and a constant current source electrically connected to the collector of the transistor; the emitter of the transistor is electrically connected to the first end of the third cable, and the base of the transistor is electrically connected to the controller.

[0050] The constant voltage source unit includes an optocoupler, a fixed resistor connected in series between the optocoupler and the controller, and a constant voltage source electrically connected to the collector of the optocoupler; the emitter of the optocoupler is electrically connected to the first end of the fourth cable.

[0051] The second end of the fourth cable 4 is connected to the second end of the fifth cable, and the first end of the fifth cable 5 is grounded after being connected in series with a reference resistor; the first ends of the first cable 1 and the second cable 2 are respectively electrically connected to the controller; the second ends of the first cable 1 and the second cable 2 are respectively electrically connected to the host.

[0052] The controller MCU also integrates a voltage acquisition module, which is used to acquire the voltage value at the first end of the fourth cable 4 and the voltage value at the first end of the fifth cable 5. The voltage value at the first end of the fifth cable is the voltage value of the reference resistor.

[0053] Example 2: Figures 1 to 6 As shown, the liquid leak detection system in this embodiment has a structure that is basically the same as that in Embodiment 1, and will not be described again here. The difference is that the liquid leak detection system in this embodiment includes multiple detection nodes, which are connected in sequence. The first detection node, which is closer to the host, has its first cable 1 and the second cable 2 electrically connected to the host, respectively. The second detection node, which is closer to the first detection node, has its first cable 1 and the second cable 2 electrically connected to the controller of the first detection node, respectively, and so on.

[0054] Each detection node is responsible for the detection work of its segment, and the controller of each detection node is responsible for transmitting the detection data of that node to the host.

[0055] Currently, the number of detection nodes in this embodiment can be set to a maximum of 64. By setting multiple detection nodes, detection over longer distances can be achieved, and multiple areas can be detected simultaneously. When multiple leakage points exist, they can be detected at the same time to avoid missed detections.

[0056] Example 3: As Figure 7 As shown, the liquid leak detection method of this embodiment includes the following steps:

[0057] S1. Disconnection Detection:

[0058] S1.1 The host's MCU processor sends a disconnection query command. The power line carrier module receives the disconnection query command, converts it, and sends it to the controller of the detection node. The controller receives the host's disconnection query command and controls the constant voltage source unit to operate. The controller controls the optocoupler to conduct and the transistor to disconnect, that is, controls the first end of the fourth cable to conduct with the control system and controls the first end of the third cable to disconnect from the control system. Figure 3 As shown, point G represents a broken line.

[0059] S1.2 The controller sends the voltage value U2 of the first end of the fifth cable to the host.

[0060] S1.3 The host receives the U2 value data and judges the received data. If U2 is zero, it is judged that a disconnection has occurred; if U2 is not zero, it is judged that the line is normal.

[0061] S2. Leakage point detection:

[0062] S2.1 The host processor sends a leak point query command. The power line carrier module receives the leak point query command, converts it, and sends it to the controller of the detection node. The controller receives the leak point query command from the host and controls the constant current source unit to operate, controls the transistor to conduct, and disconnects the optocoupler. That is, the first end of the third cable is connected to the control system, and the first end of the fourth cable is disconnected from the control system. Figure 4 As shown, when the liquid leaks, the leak point conducts through the third cable 3 and the fourth cable 4, forming a circuit. The direction of the current in this circuit is indicated by the arrow in the figure. Since the liquid is required to conduct through the third cable 3 and the fourth cable 4 for leak point measurement, the liquid to be detected in this invention must be a non-pure substance containing conductive particles. Figure 4 The leak point is located at point H in the middle.

[0063] S2.2 The controller sends the collected voltage value U11 at the first end of the fourth cable and the voltage value U12 at the first end of the fifth cable to the host.

[0064] S2.3 The host receives the U11 and U12 values ​​and judges the received data. If U11 and U12 are zero, it is determined that there is no liquid leakage; if U11 and U12 are not zero, it is determined that the liquid has leaked.

[0065] S2.4 When a liquid leak is detected, the host computer calculates the location of the leak point. The specific calculation method is as follows: Calculate the ratio of the voltage value U12 at the first end of the fifth cable to the resistance value R of the reference resistor to obtain the current value I1 in the circuit at this time; Calculate the resistance value R4 of the fourth cable in the circuit at this time based on the voltage value U12 at the first end of the fifth cable, the voltage value U11 at the first end of the fourth cable, and the current value I1; Calculate the ratio of the resistance value R4 to the resistivity ρ4 of the fourth cable to obtain the distance d between the leak point and the starting point of the second end of the fourth cable. The specific calculation formula is as follows:

[0066] I1 = U12 / R;

[0067] R4 = (U11 - U12) / I1;

[0068] d = R4 / ρ4.

[0069] This embodiment may also include a total cable length detection step to facilitate data statistics and calculation. The specific steps are as follows:

[0070] S3, Total Cable Length Inspection:

[0071] S3.1 The host's MCU processor sends a cable total length query command. The power line carrier module receives the cable total length query command, converts it, and sends it to the controller of the detection node. The controller receives the host's cable total length query command and controls the constant voltage source unit to work. The controller controls the optocoupler to conduct and the transistor to disconnect, that is, controls the first end of the fourth cable to conduct with the control system and controls the first end of the third cable to disconnect from the control system.

[0072] S3.2 The controller sends the voltage value U1 at the first end of the fourth cable and the voltage value U2 at the first end of the fifth cable to the host.

[0073] S3.3 The host receives the U1 and U2 value data.

[0074] S3.4 The host calculates the total length of the cable as follows: Calculate the ratio of the voltage U2 at the first end of the fifth cable to the resistance R of the reference resistor to obtain the current I2 in the circuit; calculate the resistance R5 of the fifth cable in the circuit based on the voltage U2 at the first end of the fifth cable, the voltage U1 at the first end of the fourth cable, and the current I2; calculate the ratio of the resistance R5 to the resistivity ρ5 of the fifth cable to obtain the total length L of the fifth cable. The specific calculation formula is as follows:

[0075] I² = U² / R;

[0076] R5 = (U1 - U2) / I2;

[0077] L = R5 / ρ5.

[0078] The S3 cable total length detection step can be performed before or after the S1 wire breakage detection step, or it can be performed after the S2 leak point detection step. There is no fixed requirement for the order of the three steps, and the three steps are continuously cycled.

[0079] Example 4: The liquid leak detection method in this example is basically the same as the detection method in Example 3, and will not be described again here. The difference is that the liquid leak detection method in this example is for the detection system in Example 2. That is to say, the detection system corresponding to the detection method in this example has multiple detection nodes. When the detection system has multiple detection nodes, each detection node is responsible for the detection work of its respective detection area.

[0080] S2. Leakage point detection:

[0081] S2.1 The host processor sends a leakage point query command. The power line carrier module receives the leakage point query command, converts it, and sends it to the controller of each detection node. Each detection node controller receives the leakage point query command from the host and controls its own constant current source unit to work, controls the corresponding transistor to conduct, and controls the optocoupler to disconnect. That is, the first end of each node's third cable is connected to the control system, and the first end of each node's fourth cable is disconnected from the control system.

[0082] S2.2 The controller of each detection node sends the voltage value U11 of the first end of the fourth cable and the voltage value U12 of the first end of the fifth cable collected by each node to the host.

[0083] S2.3 The host receives the U11 and U12 values ​​of each detection node and judges each set of data received. If U11 and U12 in a set of data are zero, it is determined that there is no liquid leakage within the detection area of ​​the corresponding detection node; if U11 and U12 in a set of data are not zero, it is determined that there is liquid leakage within the detection area of ​​the corresponding detection node.

[0084] S2.4 When a liquid leak is detected, the host computer calculates the location of the leak point, using the same calculation method as in Example 3. If multiple leak points exist, each set of data only needs to be calculated separately.

[0085] For example, if a liquid leak occurs at the first detection node, the calculation is as follows: Calculate the ratio of the voltage value U12 at the first end of the fifth cable of the first detection node to the resistance value R of the reference resistor, and obtain the current value I1 in the circuit at this time; Based on the voltage value U12 at the first end of the fifth cable, the voltage value U11 at the first end of the fourth cable, and the current value I1, calculate the resistance value R of the fourth cable in the circuit at this time. 14 ; Calculate the resistance value R 14 With the resistivity ρ of the fourth cable 14 The ratio is used to obtain the distance d1 between the leak point and the starting point of the second end of the fourth cable of the first detection node. The specific calculation formula is as follows:

[0086] I1 = U12 / R;

[0087] R 14 = (U11-U12) / I1;

[0088] d1=R 14 / ρ 14 .

[0089] For example, if a liquid leak occurs at the fourth detection node, the calculation is as follows: calculate the ratio of the voltage value U12 at the first end of the fifth cable of the fourth detection node to the resistance value R of the reference resistor, and obtain the current value I4 in the circuit at this time; based on the voltage value U12 at the first end of the fifth cable, the voltage value U11 at the first end of the fourth cable, and the current value I4, calculate the resistance value R of the fourth cable in the circuit at this time. 44 ; Calculate the resistance value R 44 With the resistivity ρ of the fourth cable 44 The ratio is used to obtain the distance d4 between the leak point and the starting point of the second end of the fourth cable of the fourth detection node. The specific calculation formula is as follows:

[0090] I4 = U12 / R;

[0091] R 44 = (U11-U12) / I4;

[0092] d4=R 44 / ρ 44 .

[0093] ...

[0094] In an embodiment of the present invention, the resistance of the reference resistor is 100Ω, the resistivity of the third and fourth cables is 13m / Ω, and the constant voltage of the constant voltage source is 3.3V.

[0095] The liquid leak detection system and method of this invention include a detection circuit comprising five cables, two of which are used for power line carrier communication, enabling long-distance and multi-regional data transmission and detection, thus broadening the detection range of liquid leaks. It utilizes a controller to control the switching states of the switching coupler and transistor, performing different detection methods by switching between a constant current source unit and a constant voltage source unit. The constant voltage source unit is used for wire breakage detection and cable length measurement, while the constant current source unit is used for liquid leak detection. This effectively distinguishes between wire breakage and leakage, avoiding false detections. The liquid leak detection system of this invention has a simple structure, low power consumption, accurate detection results, reliable detection method, simple calculation process, and high accuracy.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for detecting liquid leaks, characterized in that, Includes the following steps: The detection system includes a host and detection nodes that communicate and are electrically connected to the host. The detection node includes a control system and detection lines. The detection lines include five cables arranged in parallel in sequence. The first and second cables are power lines used to supply power to the detection nodes and transmit data. The third cable is a detection cable with a braided sheath, and the fourth cable is a rubber conductor with resistance. The fifth cable is an insulated conductor; The first end of the third cable is connected to the control system, and the first end of the fourth cable is disconnected from the control system; Obtain the voltage value U11 at the first end of the fourth cable; obtain the voltage value U12 at the first end of the fifth cable; If U11 and U12 are both zero, it is determined that there is no liquid leakage; if U11 and U12 are not both zero, it is determined that there is a liquid leakage. When a liquid leak is detected, the location of the leak point is calculated. The specific calculation method is as follows: Calculate the ratio of the voltage value U12 at the first end of the fifth cable to the resistance value R of the reference resistor to obtain the current value I1 in the circuit at this time; Calculate the resistance value R4 of the fourth cable in the circuit at this time based on the voltage value U12 at the first end of the fifth cable, the voltage value U11 at the first end of the fourth cable, and the current value I1; Calculate the ratio of the resistance value R4 to the resistivity of the fourth cable to obtain the distance d between the leak point and the starting point of the second end of the fourth cable. The control system includes a controller, a constant current source unit and a constant voltage source unit electrically connected to the controller, a first end of a third cable connected to the constant current source unit, a first end of a fourth cable connected to the constant voltage source unit, a second end of the fourth cable connected to the second end of a fifth cable, and a first end of the fifth cable connected to ground via a series reference resistor, a first end of the first cable and a second cable electrically connected to the controller, and a second end of the first cable and a second cable electrically connected to the host computer. The liquid leakage detection method also includes a wire breakage detection step: The first end of the fourth cable is connected to the control system, and the first end of the third cable is disconnected from the control system. Obtain the voltage value U2 at the first end of the fifth cable; If U2 is zero, then a disconnection has occurred. If U2 is not zero, the circuit is considered to be normal.

2. The liquid leakage detection method according to claim 1, characterized in that: It also includes a total cable length inspection step: The first end of the fourth cable is connected to the control system, and the first end of the third cable is disconnected from the control system. Obtain the voltage value U1 at the first end of the fourth cable; Obtain the voltage value U2 at the first end of the fifth cable; Calculate the ratio of the voltage value U2 at the first end of the fifth cable to the resistance value R of the reference resistor to obtain the current value I2 in the circuit at this time; calculate the resistance value R5 of the fifth cable in the circuit at this time based on the voltage value U2 at the first end of the fifth cable, the voltage value U1 at the first end of the fourth cable, and the current value I2; calculate the ratio of the resistance value R5 to the resistivity of the fifth cable to obtain the total length L of the fifth cable.

3. The liquid leakage detection method according to claim 1, characterized in that: The liquid leak detection system includes at least two detection nodes; the second ends of the first cable and the second cable of the first detection node closest to the host are electrically connected to the host, and the second ends of the first cable and the second cable of the remaining detection nodes are electrically connected to the controller of the previous detection node. The first end of the third cable of each detection node is connected to the corresponding control system, and the first end of the fourth cable of each detection node is disconnected from the corresponding control system. The voltage value U11 of the first end of the fourth cable of each detection node is obtained; the voltage value U12 of the first end of the fifth cable of each detection node is obtained. If U11 and U12 of the detection node are zero, it is determined that there is no liquid leakage at the detection node; if U11 and U12 of the detection node are not zero, it is determined that there is liquid leakage at the detection node. When a detection node determines that a liquid leak has occurred, the location of the leak point of the detection node is calculated to obtain the distance between the leak point of the detection node and the starting point of the second end of the fourth cable of the detection node.

4. A liquid leak detection system, used in the liquid leak detection method according to any one of claims 1-3, characterized in that: The system includes a host computer and detection nodes that communicate and are electrically connected to the host computer. The host computer sends instructions to the detection nodes and receives detection data transmitted by the detection nodes. The control system includes a controller, a constant current source unit and a constant voltage source unit electrically connected to the controller, a first end of a third cable connected to the constant current source unit, a first end of a fourth cable connected to the constant voltage source unit, a second end of the fourth cable connected to the second end of a fifth cable, and a first end of the fifth cable connected to ground via a series reference resistor. The first ends of the first cable and the second cable are electrically connected to the controller, respectively; the second ends of the first cable and the second cable are electrically connected to the host, respectively.

5. The liquid leak detection system according to claim 4, characterized in that: The liquid leak detection system includes at least two detection nodes; the second ends of the first cable and the second cable of the first detection node closest to the host are electrically connected to the host, and the second ends of the first cable and the second cable of the remaining detection nodes are electrically connected to the controller of the previous detection node.

6. The liquid leak detection system according to claim 5, characterized in that: The controller includes a voltage acquisition module, which is used to acquire the voltage value of the detection line.

7. The liquid leak detection system according to claim 5, characterized in that: The constant current source unit includes a transistor and a constant current source electrically connected to the collector of the transistor; the emitter of the transistor is electrically connected to the first end of the third cable, and the base of the transistor is electrically connected to the controller.

8. The liquid leak detection system according to claim 5, characterized in that: The constant voltage source unit includes an optocoupler, a fixed resistor connected in series between the optocoupler and the controller, and a constant voltage source electrically connected to the collector of the optocoupler; the emitter of the optocoupler is electrically connected to the first end of the fourth cable.

9. The liquid leak detection system according to claim 5, characterized in that: The host includes a processor and a power line carrier module electrically connected to the processor.

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