Leakage protection device and monitoring circuit applied to suspension type alternating current power supply line

Abstract

The invention discloses an electric leakage protection device applied to a suspension type alternating current power supply line and a monitoring circuit, and relates to the technical field of electric leakage protection of suspension type power supply lines. The electric leakage protection device comprises a monitoring circuit module, a signal processing module and a circuit breaker, the monitoring circuit module is coupled with the suspension type alternating current power supply line, the signal processing module is electrically connected with the monitoring circuit module, and the circuit breaker is electrically connected with the signal processing module. According to the application, the monitoring circuit module monitors the earth leakage current in the alternating current power supply line, when the electric leakage phenomenon occurs, the signal processing module generates the tripping instruction to the circuit breaker, and the circuit breaker disconnects the alternating current power supply line, so that the purpose of protecting the suspension type alternating current power supply line is achieved. According to the application, the technical effects of sensitively monitoring the electric leakage process of the suspension type alternating current power supply line and timely cutting off the circuit breaker based on the monitoring result to protect the power supply line are realized.

Description

Technical Field

[0001] This application relates to the technical field of leakage protection for suspended power supply lines, and in particular, to a leakage protection device and a monitoring circuit applied to a suspended AC power supply line. Background Art

[0002] A suspended AC power supply line refers to a power supply line that has no direct electrical connection to the ground, or has a high-impedance isolation between the entire power supply line and the ground. It is usually applied to scenarios with high requirements for electrical isolation such as ships, mining equipment, or medical equipment. However, during the use of a suspended AC power supply line, the insulation between the line and the ground may still deteriorate, for example, due to aging of the insulation layer or mechanical damage in a humid environment. Although it will not immediately form a short circuit, there are still potential safety hazards, such as the risk of personnel touching the live outer casing. Therefore, a leakage protection device in a suspended AC remote power supply line is still necessary.

[0003] Based on the working principle of the leakage protection device, in a suspended AC remote power supply line, since there is no reference ground, a suspended AC remote power supply line cannot form a loop with the ground, and conventional residual current detection methods rely on forming a loop with the ground to detect leakage in the power supply line. Therefore, conventional residual current detection methods are not applicable to suspended power supply lines, and a leakage protection and monitoring device suitable for suspended AC power supply lines needs to be designed to ensure the safety of a suspended long-distance power supply system in case of insulation deterioration or ground fault, and prevent electric shock and fire.

[0004] At the same time, problems such as impedance change and signal attenuation caused by long-distance lines will affect the reliability of the leakage protection device. Summary of the Invention

[0005] By providing a leakage protection device and a monitoring circuit applied to a suspended AC power supply line in an embodiment of this application, the technical problems in the prior art that conventional residual current detection methods are not applicable to the leakage protection detection of suspended AC power supply lines, and at the same time, during the leakage protection detection process for suspended AC power supply lines, the sensitivity of the detection circuit is insufficient and the accuracy of digital signal processing technology is insufficient are solved. The technical effect of being able to sensitively monitor the leakage process of a suspended AC power supply line, timely cut off the power supply line based on a circuit breaker when leakage occurs, and timely cut off the circuit breaker based on the monitoring result to protect the power supply line is achieved.

[0006] In a first aspect, an embodiment of the present application provides a leakage protection device applied to a floating AC power supply line, including a monitoring circuit module, a signal processing module, and a circuit breaker; two input ends of the monitoring circuit module are respectively coupled to the AC power supply line, an output end of the monitoring circuit is connected to an input end of the signal processing module, and the monitoring circuit module is configured to collect the ground leakage current of the AC power supply line in real time and output the ground leakage current to the signal processing module; the monitoring circuit module includes a voltage dividing unit and an energy-taking coil; an input end of the voltage dividing unit is coupled to the AC power supply line and is configured to perform balanced voltage division based on the voltage of the AC power supply line; an output end of the voltage dividing unit is coupled to an input end of the energy-taking coil; an output end of the energy-taking coil is connected to an input end of the signal processing module, and the energy-taking coil is configured to obtain the ground leakage current based on the voltage dividing unit and transmit the ground leakage current to the signal processing module; the signal processing module is configured to receive the ground leakage current, amplify, filter, and buffer the ground leakage current; and generate a tripping instruction based on the current signal of the ground leakage current after buffer processing and output the tripping instruction to the circuit breaker; an input end of the circuit breaker is connected to an output end of the signal processing module, a control end of the circuit breaker is coupled to the AC power supply line, and the circuit breaker is configured to perform on-off control of the AC power supply line based on the tripping instruction.

[0007] In combination with the first aspect, in a possible implementation manner, the leakage protection device further includes a power supply module; the power supply module is configured to provide a working voltage for the signal processing module; the power supply module includes a rectification unit and a voltage conversion unit; an input end of the rectification unit is coupled to an external AC power supply, an output end of the rectification unit is electrically connected to an input end of the voltage conversion unit, and the rectification unit is configured to rectify the external AC power supply; an output end of the voltage conversion unit is electrically connected to the signal processing module, and the voltage conversion unit is configured to perform DC power conversion on the rectified external AC power supply.

[0008] In combination with the first possible implementation manner of the first aspect, in a second possible implementation manner, the power supply module further includes an overvoltage protection unit; the overvoltage protection unit is connected in parallel to an output end of the voltage conversion unit, and the overvoltage protection unit is configured to trigger short-circuit protection when the working voltage abnormally increases.

[0009] In combination with the first aspect, in the third possible implementation manner, the signal processing module includes a signal amplification unit, a signal buffering unit, and an optocoupler isolation unit; the input end of the signal amplification unit is electrically connected to the monitoring circuit module, and the output end of the signal amplification unit is electrically connected to the input end of the signal buffering unit; the output end of the signal buffering unit is electrically connected to the input end of the optocoupler isolation unit; the output end of the optocoupler isolation unit is electrically connected to the circuit breaker; the signal amplification unit is configured to amplify the ground leakage current; the signal buffering unit is configured to filter and buffer the amplified ground leakage current; the optocoupler isolation unit is configured to output a tripping instruction based on the filtered and buffered ground leakage current.

[0010] In combination with the first aspect, in the fourth possible implementation manner, the energy-taking coil obtains the ground leakage current through electromagnetic induction and / or capacitive coupling.

[0011] In a second aspect, an embodiment of the present application provides a monitoring circuit applied to a suspended AC power supply line. The monitoring circuit includes the monitoring circuit module according to any one of the first aspect and the first aspect. The monitoring circuit includes a common-mode filtering circuit, a cement resistor voltage-dividing circuit, and an energy-taking coil circuit; the input end of the common-mode filtering circuit is coupled to the high-voltage phase line of the AC power supply line, and the output end of the common-mode filtering circuit is electrically connected to the input end of the cement resistor voltage-dividing circuit; the output end of the cement resistor voltage-dividing circuit is grounded; the input end of the energy-taking coil circuit is coupled between the output end of the cement resistor voltage-dividing circuit and the ground, and the output end of the energy-taking coil is electrically connected to the signal processing module; the common-mode filtering circuit is configured to filter out harmonic pulses of the current in the AC power supply line; the cement resistor voltage-dividing circuit is configured to balance the voltage of the current in the AC power supply line based on the cement resistor; the energy-taking coil circuit is configured to obtain the ground leakage current between the AC power supply line and the ground.

[0012] In combination with the second aspect, in a possible implementation manner, the common-mode filtering circuit includes a transformer U7, a transformer U8, a capacitor C15, a capacitor C16, and a capacitor C17; two input ends of the transformer U7 are respectively coupled to two high-voltage phase lines of the AC power supply line, and two output ends of the transformer U7 are respectively electrically connected to two input ends of the transformer U8; two output ends of the transformer U8 are both electrically connected to the cement resistor voltage-dividing circuit; the capacitor C15 is connected in parallel with two output ends of the transformer U7; the capacitor C16 and the capacitor C17 are connected in series and then connected in parallel with two output ends of the transformer U8.

[0013] In combination with the second aspect, in the second possible implementation manner, the cement resistor voltage dividing circuit includes resistor R22 and resistor R23; one end of resistor R22 and one end of resistor R23 are both electrically connected to the common-mode filtering circuit, and the other end of resistor R22 and the other end of resistor R23 are grounded; the resistance values of resistor R22 and resistor R23 are equal.

[0014] In combination with the second aspect, in the third possible implementation manner, the energy-taking coil circuit obtains the ground leakage current between the cement resistor voltage dividing circuit and the ground through electromagnetic induction and / or capacitive coupling.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: In the embodiments of the present application, by coupling the input end of the monitoring circuit module to two high-voltage phase lines of the floating AC power supply line and performing voltage division on the high voltage based on the voltage dividing unit, the voltage between the voltage dividing unit and the ground reaches an equilibrium state and the current approaches 0. When the AC power supply line leaks electricity, the voltage equilibrium state is broken and the current increases to a maximum of 5 mA. The signal processing module processes the ground leakage current in the leakage state and generates a tripping instruction, and the circuit breaker controls the air switch of the AC power supply line to trip based on this tripping instruction. The technical effect of being able to sensitively monitor the leakage process of the floating AC power supply line and timely cut off the circuit breaker based on the monitoring result to protect the power supply line is achieved. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a framework diagram of a leakage protection device for a floating AC power supply line provided by an embodiment of the present application; Figure 2 It is a framework diagram of a power supply module provided by an embodiment of the present application; Figure 3 It is a framework diagram of a signal processing module provided by an embodiment of the present application; Figure 4 It is a circuit diagram of a monitoring circuit provided by an embodiment of the present application. Detailed Embodiments

[0018] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Different from traditional power supply lines, a floating AC power supply line does not have a zero line or neutral line in the traditional sense. There are only two high-voltage phase lines. One is connected to a fuse, and the other is connected to a high-voltage lightning protection line. The AC voltage between the two high-voltage phase lines reaches 600V - 1500V, and the current only flows between the two high-voltage phase lines and does not return through the ground. At the same time, a floating AC remote power supply line can also use a three-phase line. When using a three-phase line, each phase is still floating relative to the ground, not grounded, without a neutral line, and the load operates through the phase-to-phase voltage.

[0020] The neutral point of the AC power supply line is not directly grounded, or there is a high-impedance isolation between the entire AC power supply line and the ground. In a floating AC power supply line, there is no direct electrical connection point between the line and the ground as a reference point for leakage. The floating AC power supply line cannot form a loop with the ground. Therefore, the embodiments of the present application propose a leakage protection device and a monitoring circuit that can achieve leakage monitoring and leakage protection based on a floating AC power supply line (live wire and neutral wire) to improve the power supply continuity and safety of the floating AC power supply line.

[0021] Figure 1 is a framework diagram of the leakage protection device for a floating AC power supply line provided by the embodiments of the present application. As Figure 1 shown, the leakage protection device described in the embodiments of the present application includes a monitoring circuit module, a signal processing module, and a circuit breaker.

[0022] The two input terminals of the monitoring circuit module are respectively coupled to the two high-voltage phase lines of the floating AC power supply line. The monitoring circuit module is used to collect the leakage current to the ground between the AC power supply lines in real time. When the AC power supply line leaks, the current and voltage between the two high-voltage phase lines change relatively, a loop is generated between the high-voltage phase line and the ground, and a leakage current to the ground is generated. The monitoring circuit module can monitor this leakage current to the ground in real time. At the same time, the monitoring circuit module is also used to transmit the leakage current to the ground between the two high-voltage phase lines to the signal processing module.

[0023] In the embodiment of the present application, the monitoring circuit module includes a voltage dividing unit and an energy-taking coil. The voltage dividing unit is electrically connected to the AC power supply line and is used to balance and divide the voltage in the AC power supply line so that the voltage between the two high-voltage phase lines is in a balanced state. When the balanced state between the voltages is broken, it proves that there is a ground leakage in the AC power supply line, generating a ground leakage current. When the balanced state between the voltages is broken, the energy-taking coil obtains the ground leakage current based on the electromagnetic induction phenomenon and transmits the ground leakage current to the signal processing module.

[0024] The input end of the signal processing module is connected to the output end of the monitoring circuit module. The signal processing module is used to receive the ground leakage current output by the monitoring circuit module and process the ground leakage current generated by the two high-voltage phase lines. Specifically, the processing process includes amplifying, filtering, and buffering the ground leakage current. And a tripping instruction is generated based on the current signal of the processed ground leakage current.

[0025] The input end of the circuit breaker is connected to the output end of the signal processing module. At the same time, the control end (i.e., the output end) of the circuit breaker is respectively coupled to the air switches on the two high-voltage phase lines of the AC power supply line. The circuit breaker is used to disconnect the air switches based on the tripping instruction output by the signal processing module, thereby realizing the on-off control of the AC power supply line.

[0026] In the embodiment of the present application, by coupling the input end of the monitoring circuit module to the two high-voltage phase lines of the AC power supply line and voltage-dividing the high voltage based on the voltage dividing unit, the voltage between the voltage dividing unit and the ground reaches a balanced state and the current approaches 0. When the power supply line leaks electricity, the balanced state of the voltage is broken, generating a ground leakage current. The maximum value of the ground leakage current reaches 5 mA. The signal processing module processes the ground leakage current and generates a tripping instruction. The circuit breaker controls the air switch to disconnect the AC power supply line based on this tripping instruction. The present application realizes the technical effect of being able to sensitively monitor the leakage process of the floating AC power supply line and timely cut off the circuit breaker based on the monitoring result to protect the AC power supply line.

[0027] Figure 2 This is the framework diagram of the power supply module provided by the embodiment of the present application. As Figure 2 shown, in the embodiment of the present application, the floating AC power supply line leakage protection device further includes a power supply module. The power supply module includes a rectifying unit, a voltage conversion unit, and an overvoltage protection unit. The power supply module is used to provide a working voltage for the signal processing module to ensure the normal operation of the signal processing module.

[0028] Specifically, the input end of the rectification unit is electrically connected to an external power supply (mainly the 220V commercial power supply, which is alternating current), the output end of the rectification unit is electrically connected to the input end of the voltage conversion unit, an overvoltage protection unit is connected in parallel to the output end of the voltage conversion unit, and at the same time, the output end of the voltage conversion unit is electrically connected to the signal processing module.

[0029] The rectification unit performs output rectification on the input 220V alternating current, and the voltage conversion unit performs AC-DC voltage conversion on the rectified input voltage. Specifically, a +5V DC working voltage is generated based on a voltage regulator, and a -5V DC working voltage is generated based on a voltage converter. The +5V working voltage and the -5V working voltage jointly provide the working voltage for the signal processing module.

[0030] Exemplarily, in the embodiment of the present application, the voltage regulator can be a three-terminal voltage regulator with the model number L7805CDT. The voltage converter can be a switched-capacitor voltage converter with the model number TC7660M / TR.

[0031] The overvoltage protection unit is connected in parallel to the output end of the voltage conversion unit and is used to monitor the working voltage. When the working voltage abnormally rises, short-circuit protection is triggered to disconnect the connection between the voltage conversion unit and the signal processing module.

[0032] In the embodiment of the present application, the energy-taking coil realizes obtaining the ground leakage current of two high-voltage phase lines in the AC power supply line through electromagnetic induction and / or capacitive coupling.

[0033] Figure 3 This is the framework diagram of the signal processing module provided by the embodiment of the present application. As Figure 3 shown, in the embodiment of the present application, the signal processing module includes a signal amplification unit, a signal buffering unit, and an optocoupler isolation unit.

[0034] Specifically, the input end of the signal amplification unit is electrically connected to the monitoring circuit module, and the output end of the signal amplification unit is electrically connected to the input end of the signal buffering unit. The output end of the signal buffering unit is electrically connected to the optocoupler isolation unit. The optocoupler isolation unit is electrically connected to the circuit breaker.

[0035] It should be noted that in order to rectify the ground leakage current output by the signal buffering unit, a rectifier needs to be provided between the signal buffering unit and the optocoupler isolation unit.

[0036] The signal amplification unit is used to amplify the ground leakage current output by the monitoring circuit module, and the signal buffer unit filters and buffers the amplified ground leakage current. After filtering and buffering, the ground leakage current passes through the optocoupler isolation unit and is output as an optical signal (equivalent to the current signal of the ground leakage current). At the same time, the signal processing module generates a trip instruction based on the optical signal, and then controls the circuit breaker to operate based on the trip instruction (i.e., controls the air switch in the AC power supply line to trip).

[0037] The operating voltages of the signal amplification unit, the signal buffer unit, and the rectifier all come from the operating voltage output by the power supply module.

[0038] Exemplarily, in the signal amplification unit, the operational amplifier with the model number AD620ARZ can be selected as the main electronic component for signal amplification. For filtering and buffering the current, the low-power dual operational amplifier with the model number LM358DR can be selected. In the optocoupler isolation unit, the optocoupler with the model number EL817S1 can be selected to realize the control signal output based on the filtered and buffered current.

[0039] Figure 4 This is the circuit diagram of the monitoring circuit provided by the embodiment of the present application. As Figure 4 shown, the embodiment of the present application also provides a monitoring circuit applied to a floating AC power supply line. This monitoring circuit mainly includes the monitoring circuit module described in the embodiment of the present application. Specifically, the monitoring circuit includes a common-mode filter circuit, a cement resistor voltage division circuit, and an energy-taking coil circuit.

[0040] The input end of the common-mode filter circuit is connected to two high-voltage phase lines (i.e., Figure 4 L1 and L2 in) in the AC power supply line, the output end is connected to the input end of the cement resistor voltage division circuit, and the output end of the cement resistor voltage division circuit is grounded. The input end of the energy-taking coil circuit is coupled between the output end of the cement resistor voltage division circuit and the ground, and the output end of the energy-taking coil is electrically connected to the signal processing module.

[0041] Specifically, the common-mode filter circuit is used to filter out the harmonic pulses of the current in the acquired AC power supply line. The cement resistor voltage division circuit realizes the balanced voltage division of the filtered voltage through the cement resistor in the circuit. The energy-taking coil is used to obtain the maximum ground leakage current of 5 mA generated by the cement resistor voltage division circuit when there is a ground leakage phenomenon in the AC power supply line.

[0042] Exemplarily, as Figure 4 shown, the common-mode filter circuit includes transformers U7, U8, capacitors C15, C16, and C17.

[0043] The two input terminals of transformer U7 are respectively coupled to two high-voltage phase lines (i.e., L1 and L2) of the AC power supply line, and the two output terminals of transformer U7 are respectively electrically connected to the two input terminals of transformer U8; the two output terminals of transformer U8 are both electrically connected to the cement resistor voltage-dividing circuit. Capacitor C15 is connected in parallel with the two output terminals of transformer U7; capacitors C16 and C17 are connected in series and then connected in parallel with the two output terminals of transformer U8.

[0044] In the cement resistor voltage-dividing circuit, it includes resistor R22 and resistor R23. One end of resistor R22 and one end of resistor R23 are both electrically connected to the common-mode filtering circuit, and the other end of resistor R22 and the other end of resistor R23 are both grounded.

[0045] It should be noted that the resistance values of resistor R22 and resistor R23 are equal to ensure that the cement resistor voltage-dividing circuit can achieve balanced voltage division and ensure that the current between the cement resistor voltage-dividing circuit and the ground approaches 0.

[0046] In the energy-taking coil circuit, it includes current-type voltage transformer L2, zero-sequence current transformer L1, resistor R3, resistor R4, and resistor R5.

[0047] One end of current-type voltage transformer L2 is provided with a hole, and the hole is sleeved on the wire between the cement resistor voltage-dividing circuit and the ground. The output terminal of current-type voltage transformer L2 is electrically connected to the signal processing module.

[0048] At the same time, zero-sequence current transformer L1 is also of a ring structure, and the ring of zero-sequence current transformer L1 is sleeved on the wire between the cement resistor voltage-dividing circuit and the ground. One end of zero-sequence current transformer L1 is connected in series with resistor R5 and resistor R3 and then electrically connected to the signal processing module, and the other end is connected in series with resistor R4 and then electrically connected to the signal processing module.

[0049] Exemplarily, the model of zero-sequence current transformer L1 can be selected as ZCT101. The model of current-type voltage transformer L2 is ZHT102.

[0050] Both zero-sequence current transformer L1 and current-type voltage transformer L2 monitor the ground leakage current between the cement resistor voltage-dividing circuit and the ground through electromagnetic induction and / or capacitive coupling.

[0051] The leakage protection device provided by the embodiments of the present application is mainly used at the AC remote power supply bureau end. Its core function is to monitor the vector difference between the inflowing and outflowing currents in the loop of the floating AC power supply line. When the power supply line is in a normal power supply state, the current change monitored by the monitoring circuit module approaches 0, and the voltages at both ends of the two cement resistors in the voltage dividing unit are in a balanced state; when a leakage phenomenon occurs between the loops of the power supply line, the balanced state of the voltage is broken, a vector difference in current is generated, and the current output by the voltage dividing unit reaches 5 mA. This current is the ground leakage current. When the ground leakage current passes through the monitoring circuit module, it is transmitted to the signal processing module through the energy-taking coil. The signal processing module processes the ground leakage current and outputs a tripping instruction to the circuit breaker based on the processed ground leakage current. The circuit breaker trips the air switches between the lines of the power supply line, thereby realizing the protection of the floating AC power supply line with leakage.

[0052] The device or module described in the above embodiments of the application can be specifically implemented by a computer chip or an entity, or by a product with a certain function. For the convenience of description, when describing the above device, it is divided into various modules according to functions and described separately. When implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0053] In addition, in each embodiment of the present invention, the functional modules can be integrated into one processing module, or each module can exist independently, or two or more modules can be integrated into one module.

[0054] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. The focus of each embodiment is to illustrate the differences from other embodiments. All or part of the present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A leakage protection device applied to a suspended AC power supply line, characterized in that, It includes a monitoring circuit module, a signal processing module and a circuit breaker; Two input ends of the monitoring circuit module are respectively coupled to an AC power supply line, an output end of the monitoring circuit is connected to an input end of the signal processing module, and the monitoring circuit module is configured to collect the ground leakage current of the AC power supply line in real time and output the ground leakage current to the signal processing module; The monitoring circuit module includes a voltage dividing unit and an energy taking coil; an input end of the voltage dividing unit is coupled to the AC power supply line and is configured to perform balanced voltage division based on the voltage of the AC power supply line; an output end of the voltage dividing unit is coupled to an input end of the energy taking coil; an output end of the energy taking coil is connected to an input end of the signal processing module, and the energy taking coil is configured to obtain the ground leakage current based on the voltage dividing unit and transmit the ground leakage current to the signal processing module; The signal processing module is configured to receive the ground leakage current and perform amplification, filtering and buffering processing on the ground leakage current; And generate a tripping instruction based on the current signal of the ground leakage current after buffering processing, and output the tripping instruction to the circuit breaker; An input end of the circuit breaker is connected to an output end of the signal processing module, a control end of the circuit breaker is coupled to the AC power supply line, and the circuit breaker is configured to perform on-off control of the AC power supply line based on the tripping instruction.

2. The leakage protection device according to claim 1, characterized in that The leakage protection device further includes a power supply module; The power supply module is configured to provide a working voltage for the signal processing module; the power supply module includes a rectifying unit and a voltage conversion unit; An input end of the rectifying unit is coupled to an external AC power supply, an output end of the rectifying unit is electrically connected to an input end of the voltage conversion unit, and the rectifying unit is configured to rectify the external AC power supply; An output end of the voltage conversion unit is electrically connected to the signal processing module, and the voltage conversion unit is configured to perform DC power conversion on the rectified external AC power supply.

3. The leakage protection device according to claim 2, characterized in that, The power supply module further includes an overvoltage protection unit; the overvoltage protection unit is connected in parallel to an output end of the voltage conversion unit, and the overvoltage protection unit is configured to trigger short-circuit protection when the working voltage abnormally rises.

4. The leakage protection device according to claim 1, characterized in that, The signal processing module includes a signal amplification unit, a signal buffering unit and an opto-isolation unit; An input end of the signal amplification unit is electrically connected to the monitoring circuit module, an output end of the signal amplification unit is electrically connected to an input end of the signal buffering unit; an output end of the signal buffering unit is electrically connected to an input end of the opto-isolation unit; an output end of the opto-isolation unit is electrically connected to the circuit breaker; The signal amplification unit is configured to amplify the ground leakage current; the signal buffering unit is configured to filter and buffer the amplified ground leakage current; The opto-isolation unit is configured to output a tripping instruction based on the filtered and buffered ground leakage current.

5. The leakage protection device according to claim 1, characterized in that, The energy taking coil obtains the ground leakage current through electromagnetic induction and / or capacitive coupling.

6. A monitoring circuit applied to a suspended AC power supply line, the monitoring circuit comprising the monitoring circuit module according to any one of claims 1-5, characterized in that, The monitoring circuit includes a common-mode filtering circuit, a cement resistor voltage-dividing circuit, and an energy-taking coil circuit; The input end of the common-mode filtering circuit is coupled to the high-voltage phase line of the AC power supply line, and the output end of the common-mode filtering circuit is electrically connected to the input end of the cement resistor voltage-dividing circuit; the output end of the cement resistor voltage-dividing circuit is grounded; The input end of the energy-taking coil circuit is coupled between the output end of the cement resistor voltage-dividing circuit and the ground, and the output end of the energy-taking coil is electrically connected to the signal processing module; The common-mode filtering circuit is configured to filter out the harmonic pulses of the current in the AC power supply line; The cement resistor voltage-dividing circuit is configured to balance the voltage of the current in the AC power supply line based on the cement resistor; The energy-taking coil circuit is configured to obtain the ground leakage current between the AC power supply line and the ground; 7. The monitoring circuit according to claim 6, wherein The common-mode filtering circuit includes a transformer U7, a transformer U8, a capacitor C15, a capacitor C16, and a capacitor C17; The two input ends of the transformer U7 are respectively coupled to the two high-voltage phase lines of the AC power supply line, and the two output ends of the transformer U7 are respectively electrically connected to the two input ends of the transformer U8; the two output ends of the transformer U8 are both electrically connected to the cement resistor voltage-dividing circuit; The capacitor C15 is connected in parallel with the two output ends of the transformer U7; the capacitor C16 and the capacitor C17 are connected in series and then connected in parallel with the two output ends of the transformer U8; 8. The monitoring circuit according to claim 6, wherein The cement resistor voltage-dividing circuit includes a resistor R22 and a resistor R23; One end of the resistor R22 and one end of the resistor R23 are both electrically connected to the common-mode filtering circuit, and the other end of the resistor R22 and the other end of the resistor R23 are grounded; The resistance values of the resistor R22 and the resistor R23 are equal; 9. The monitoring circuit according to claim 6, characterized in that, The energy-taking coil circuit obtains the ground leakage current between the cement resistor voltage-dividing circuit and the ground through electromagnetic induction and / or capacitive coupling.

Images