An electric leakage protection circuit

Abstract

The application discloses a kind of electric leakage protection circuit.The electric leakage protection circuit includes: control switch, electric leakage detection circuit, reset circuit and electric leakage protection drive circuit;Electric leakage detection circuit is used to detect when electric leakage occurs in power line, generates electric leakage signal;Electric leakage protection drive circuit is used to receive electric leakage signal, and drive control switch to open;Reset circuit is used to reset electric leakage protection drive circuit;Electric leakage detection circuit generates electric leakage signal when electric leakage occurs in power line, and output to electric leakage protection drive circuit, electric leakage protection drive circuit controls control switch to open according to electric leakage signal, realizes the electric leakage protection of power line;After electric leakage of power line is removed, reset circuit triggers reset drive signal, so that electric leakage signal is eliminated, and electric leakage protection drive circuit drives control switch to close.The technical scheme of the embodiment of the application can quickly control power line to open when electric leakage occurs in power line, to achieve the effect of electric leakage protection.

Description

Technical Field

[0001] This invention relates to the field of leakage current protection technology, and in particular to a leakage current protection circuit. Background Technology

[0002] In power systems, residual current devices (RCDs) are essential electrical equipment. With the development of electronic technology, various intelligent RCDs have emerged.

[0003] Most existing intelligent residual current devices (RCDs) use software processors for control, responding to leakage current in power lines. However, software processors require a certain amount of time to respond to leakage current, and due to unstable power supplies or surrounding electromagnetic interference, they are prone to program crashes or freezes, resulting in low reliability. Summary of the Invention

[0004] This invention provides a leakage current protection circuit to quickly disconnect the power line when leakage occurs, thereby achieving the effect of leakage current protection.

[0005] According to one aspect of the present invention, a leakage current protection circuit is provided, the circuit comprising: a control switch, a leakage current detection circuit, a reset circuit, and a leakage current protection drive circuit;

[0006] The control switch is connected in series with the power line;

[0007] The leakage current detection circuit is electrically connected to a current transformer installed on the power line. The leakage current detection circuit is used to generate a leakage current signal when the power line is detected to have leakage current based on the output of the current transformer.

[0008] The leakage protection drive circuit is electrically connected to the leakage detection circuit and the control switch. The leakage protection drive circuit is used to drive the control switch to open when it receives the leakage signal.

[0009] The reset circuit is connected to the leakage current detection circuit and is used to reset the leakage current detection circuit in order to reset the leakage current protection drive circuit.

[0010] When a leakage occurs in the power line, the leakage detection circuit generates a leakage signal and outputs the leakage signal to the leakage protection drive circuit. The leakage protection drive circuit controls the control switch to open according to the leakage signal, thereby realizing leakage protection of the power line. After the power line leakage is resolved, the user triggers the reset circuit to eliminate the leakage signal, and the leakage protection drive circuit drives the control switch to close, restoring the power line to its initial state.

[0011] Optionally, the leakage protection circuit further includes: a control module; the leakage protection drive circuit is electrically connected to the control module; when no leakage occurs in the power line, the control module controls the leakage protection drive circuit to open or close the control switch; when leakage occurs in the power line, the control module cannot control the leakage protection drive circuit to close the control switch.

[0012] Optionally, when the power line is operating normally, the user can control the control switch to close or open by triggering the reset circuit.

[0013] Optionally, the leakage protection circuit may also include: a status detection circuit;

[0014] The status detection circuit is electrically connected to the power line and the control module. The status detection circuit is used to detect whether the control switch performs the corresponding leakage protection action and output a second status signal to the control module.

[0015] The control module determines whether the control switch is effectively disconnected based on the leakage signal and the second status signal.

[0016] Optionally, the control switch includes: an electrically holding relay; the electrically holding relay includes: an electromagnetic coil and a relay switch, the relay switch being connected in series with the power line;

[0017] The electromagnetic coil is used to control the relay switch to close when current flows through it, and to control the relay switch to open when no current flows through it.

[0018] The leakage protection drive circuit includes: a first transistor, a second transistor, a first resistor, a second resistor, and a third resistor;

[0019] The control terminal of the first transistor is connected to the leakage signal through the first resistor. The first terminal of the first transistor is electrically connected to the control terminal of the second transistor, and the second terminal of the first transistor is grounded. The control terminal of the second transistor is electrically connected to the control module through the second resistor. The first terminal of the second transistor is electrically connected to the electromagnetic coil of the electrically holding relay, and the second terminal of the second transistor is grounded. The third resistor is electrically connected between the control terminal and the ground terminal of the second transistor.

[0020] Optionally, the leakage current detection circuit includes: a detection chip, a first thyristor, a first diode, a fourth resistor, a fifth resistor, and a first capacitor;

[0021] The detection chip is electrically connected to the current transformer and the gate of the first thyristor. The anode of the first thyristor is electrically connected to the first power supply through the fourth resistor. The cathode of the first thyristor is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the reset circuit. The fifth resistor is electrically connected between the anode of the first diode and the ground terminal. The first capacitor is connected in parallel between the gate of the first thyristor and the ground terminal. The detection chip is used to drive the first thyristor to conduct according to the current signal output by the current transformer.

[0022] Optionally, the reset circuit includes: a third transistor, a sixth resistor, a current limiting unit, a reset button, and a leakage current reporting unit;

[0023] The control terminal of the third transistor is electrically connected to the first power supply through the current limiting unit. The first terminal of the third transistor is electrically connected to the cathode of the first diode. The second terminal of the third transistor is grounded, and the first terminal of the third transistor is electrically connected to the first power supply through the sixth resistor. The two ends of the reset button are connected in parallel to the current limiting unit and the ground terminal. The input terminal of the leakage current reporting unit is electrically connected to the anode of the first diode, and the output terminal of the leakage current reporting unit is electrically connected to the control module. The leakage current reporting unit is used to transmit the leakage current signal to the control module so that the control module reports the leakage current status.

[0024] The first thyristor, the first diode, and the first transistor form a circuit, and the leakage signal is the voltage at the anode of the first diode.

[0025] Optionally, the state detection circuit includes: an optocoupler, a seventh resistor, and a rectification and current limiting unit;

[0026] The rectification and current limiting unit is electrically connected between the optocoupler and the power line. The rectification and current limiting unit is used to rectify the current in the power line and output the rectified current to the optocoupler.

[0027] The first output terminal of the optocoupler is grounded, the second output terminal of the optocoupler is electrically connected to the control module, and the seventh resistor is electrically connected between the second output terminal of the optocoupler and the second power supply.

[0028] Optionally, the control switch includes a magnetic latching relay; the magnetic latching relay includes a closing coil, a closing coil, and a relay switch, the relay switch being connected in series with the power line; the closing coil is used to control the relay switch to close when current flows through it; the closing coil is used to control the relay switch to open when current flows through it.

[0029] The leakage protection drive circuit includes: a fourth transistor, a fifth transistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor;

[0030] The control terminal of the fourth transistor is electrically connected to the control module through the eighth resistor. The first terminal of the fourth transistor is electrically connected to the turn-off coil, and the leakage current detection circuit is electrically connected between the first terminal of the fourth transistor and the turn-off coil. The second terminal of the fourth transistor is grounded. The control terminal of the fifth transistor is electrically connected to the control module through the ninth resistor. The first terminal of the fifth transistor is electrically connected to the closed coil, and the second terminal of the fifth transistor is grounded. The tenth resistor is electrically connected between the control terminal and the ground terminal of the fourth transistor, and the eleventh resistor is electrically connected between the control terminal and the ground terminal of the fifth transistor.

[0031] Optionally, the leakage current detection circuit includes: a detection chip, a second thyristor, a first diode, a twelfth resistor, and a second capacitor;

[0032] The detection chip is electrically connected to the current transformer and the gate of the second thyristor. The anode of the second thyristor is electrically connected to the first terminal of the fourth transistor. The cathode of the second thyristor is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the reset circuit. The twelfth resistor is electrically connected between the cathode of the second thyristor and the ground terminal. The second capacitor is connected in parallel between the gate of the second thyristor and the ground terminal. The detection chip is used to drive the second thyristor to conduct according to the current signal output by the current transformer.

[0033] Optionally, the reset circuit includes: a third transistor, a thirteenth resistor, a current limiting unit, a reset button, and a leakage current reporting unit;

[0034] The control terminal of the third transistor is electrically connected to the state detection circuit through the current limiting unit. The first terminal of the third transistor is electrically connected to the cathode of the first diode. The second terminal of the third transistor is grounded, and the first terminal of the third transistor is electrically connected to the first power supply through the thirteenth resistor. The two ends of the reset button are connected in parallel to the current limiting unit and the ground terminal. The input terminal of the leakage current reporting unit is electrically connected to the anode of the first diode, and the output terminal of the leakage current reporting unit is electrically connected to the control module. The leakage current reporting unit is used to transmit the leakage current signal to the control module so that the control module reports the leakage current status.

[0035] Optionally, the state detection circuit includes: an optocoupler, a rectification and current limiting unit, a sixth transistor, and a fourteenth resistor;

[0036] The rectification and current limiting unit is electrically connected between the optocoupler and the power line. The rectification and current limiting unit is used to rectify the current in the power line and output the rectified current to the optocoupler.

[0037] The second output terminal of the optocoupler is electrically connected to the first power supply, the first output terminal of the optocoupler is electrically connected to the control terminal of the sixth transistor through the fourteenth resistor, the first terminal of the sixth transistor is electrically connected to the control module, and the second terminal of the sixth transistor is grounded.

[0038] Optionally, the current limiting unit includes: a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor;

[0039] The fifteenth resistor is electrically connected between the control terminal of the third transistor and the reset button;

[0040] The sixteenth resistor and the seventeenth resistor are connected in series between the first power supply and the ground terminal, or...

[0041] The sixteenth resistor and the seventeenth resistor are connected in series between the first output terminal and the ground terminal of the optocoupler.

[0042] Optionally, the leakage current reporting unit includes: a seventh transistor and an eighteenth resistor;

[0043] The control terminal of the seventh transistor is electrically connected to the anode of the first diode through the eighteenth resistor, the first terminal of the seventh transistor is electrically connected to the control module, and the second terminal of the seventh transistor is grounded.

[0044] Optionally, the rectification and current limiting unit includes: a varistor, a second diode, a third capacitor, at least one nineteenth resistor and a twentyth resistor;

[0045] The varistor is connected in series with the power line; the anode of the second diode is connected to the second input terminal of the optocoupler, and the cathode of the second diode is connected to one end of the varistor; at least one nineteenth resistor and the twentieth resistor are connected in series with the other end of the varistor and the first input terminal of the optocoupler; the third capacitor is connected in parallel with the twentieth resistor and the second input terminal of the optocoupler.

[0046] Optionally, the circuit further includes: a status indicator circuit; the status indicator circuit includes: a first light-emitting diode, a second light-emitting diode, a twenty-first resistor, and a twenty-second resistor;

[0047] The anode of the first LED is electrically connected to the control module through the 21st resistor; the anode of the second LED is electrically connected to the control module through the 22nd resistor; the cathodes of both the first and second LEDs are grounded.

[0048] The leakage current protection circuit provided by this invention detects leakage in the power line through a leakage current detection circuit, generates a leakage current signal, and transmits it to the leakage current protection drive circuit. The leakage current protection drive circuit responds to the leakage current signal, executes leakage current protection action, and controls the control switch to open, thereby achieving leakage current protection for the power line. Using a leakage current protection circuit improves the response speed to leakage in the power line, quickly executes leakage current protection, and enhances the reliability of the leakage current protection function.

[0049] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0051] Figure 1 This is a schematic diagram of a leakage current protection circuit according to an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of another leakage protection circuit provided according to an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of another leakage protection circuit provided according to an embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the structure of a control module for a leakage current protection circuit according to an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of another leakage protection circuit provided according to an embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the structure of a control module for another leakage current protection circuit provided according to an embodiment of the present invention. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] This invention provides a leakage current protection circuit. Figure 1 This is a schematic diagram of a leakage current protection circuit provided in an embodiment of the present invention. Figure 1 As shown, the leakage protection circuit includes: a control switch 10, a leakage detection circuit 20, a reset circuit 30, and a leakage protection circuit 40.

[0060] The control switch 10 is connected in series with the power line. The leakage detection circuit 20 is electrically connected to the current transformer L1 installed in the power line. When the leakage detection circuit 20 detects a leakage in the power line based on the output of the current transformer L1, it generates a leakage signal. The leakage protection drive circuit 40 is electrically connected to the leakage detection circuit 20 and the control switch 10. When the leakage protection drive circuit 40 receives the leakage signal, it drives the control switch 10 to open. The reset circuit 30 is connected to the leakage detection circuit 20 and is used to reset the leakage detection circuit 20, thereby resetting the leakage protection drive circuit 40.

[0061] When a leakage occurs in the power line, the leakage detection circuit 20 generates a leakage signal and outputs the leakage signal to the leakage protection drive circuit 40. The leakage protection drive circuit 40 controls the control switch 10 to open according to the leakage signal, thereby realizing the leakage protection of the power line. After the power line leakage is cleared, the user triggers the reset circuit 30 to eliminate the leakage signal. The leakage protection drive circuit 40 then drives the control switch 10 to close, and the power line returns to its initial state.

[0062] Specifically, control switch 10 is connected in series in the power line. When control switch 10 is closed, the power line is in a conducting state; when control switch 10 is open, the power line is in a disconnected state. A current transformer L1 is also provided in the power line. For example, current transformer L1 can be a zero-sequence current transformer. Current transformer L1 can detect whether leakage has occurred in the power line. When leakage occurs, the vector sum of the currents through current transformer L1 is not zero. The secondary winding of current transformer L1 can generate a voltage signal and transmit the voltage signal to leakage detection circuit 20, triggering leakage detection circuit 20 to form a current path and generate a leakage signal. For example, control module 60 can be a microcontroller unit (MCU) or a system-on-chip (SoC).

[0063] The leakage current detection circuit 20 generates a leakage current signal, which is transmitted to the leakage current protection drive circuit 40. The leakage current protection drive circuit 40 controls the leakage current protection action, and the leakage current protection drive circuit 40 controls the control switch 10 to open, so that the power line is in an open state, thereby realizing leakage current protection for the power line.

[0064] When the power line is working normally, the control module ( Figure 1 (Not shown in the diagram) By outputting a corresponding level signal to the leakage protection drive circuit 40, the leakage protection drive circuit 40 can control the control switch 10 to close or open, thereby controlling the conduction or disconnection of the power line. When a leakage occurs in the power line, the leakage protection circuit responds quickly, controlling the control switch 10 to open, and can maintain the power line in an open state until the leakage is eliminated. When the leakage fault in the power line is cleared, the drive reset circuit 30 is activated, causing the leakage detection circuit 20 to return to its initial state, and the leakage signal disappears. Therefore, the level signal output by the control module re-drives the leakage protection drive circuit 40, controlling the power line to close, thereby causing the leakage protection drive circuit 40 to control the control switch 10 to return to its initial state, that is, the power line to return to the conducting state.

[0065] The leakage current protection circuit provided in this embodiment detects leakage in the power line through a leakage current detection circuit, generates a leakage current signal, and transmits it to the leakage current protection drive circuit. The leakage current protection drive circuit responds to the leakage current signal, executes leakage current protection action, and controls the control switch to open, thereby achieving leakage current protection for the power line. Using a leakage current protection circuit improves the response speed to leakage in the power line, quickly executes leakage current protection, and enhances the reliability of the leakage current protection function.

[0066] Optional, Figure 2 This is a schematic diagram of another leakage current protection circuit provided in an embodiment of the present invention. Based on the above embodiments, as follows... Figure 2As shown, the leakage protection circuit also includes a control module 60. The leakage protection drive circuit 40 is electrically connected to the control module 60; when no leakage occurs in the power line, the control module 60 controls the leakage protection drive circuit 40 to open or close the control switch 10; when leakage occurs in the power line, the control module 60 cannot control the leakage protection drive circuit 40 to close the control switch 10.

[0067] Specifically, when no leakage occurs in the power line, the control module 60 sends a corresponding level signal to the leakage protection drive circuit 40, causing the leakage protection drive circuit 40 to control the power line to be turned on or off. When a leakage occurs in the power line, the leakage signal drives the leakage protection drive circuit, causing the control switch 10 to open. At this time, the control module 60 does not have the function of driving the leakage protection drive circuit 40.

[0068] Optionally, based on the above embodiments, see also... Figure 2 When the power line is operating normally, the user can control the control switch 10 to close or open by triggering the reset circuit 30.

[0069] Specifically, when there is no leakage in the power line, the user can trigger the reset circuit 30, which sends a reset signal to the control module 60, thereby enabling the control module 60 to control the power line to be turned on or off.

[0070] Optionally, based on the above embodiments, see also... Figure 2 The leakage current protection circuit also includes a status detection circuit 50 and a control module 60. The status detection circuit 50 is electrically connected to the power line and the control module 60. The status detection circuit 50 is used to detect whether the control switch 10 performs the corresponding leakage current protection action and outputs a second status signal to the control module 60. The control module 60 determines whether the control switch 10 is effectively disconnected based on the leakage current signal and the second status signal.

[0071] Specifically, the status detection circuit 50 is connected in series downstream of the control switch 10 on the power line. The status detection circuit 50 can detect whether the power line is in a conducting or disconnected state to determine whether the control switch 10 has performed a leakage current protection action. The status detection circuit 50 generates a second status signal based on the power line status and transmits this signal to the control module 60. The control module 60 compares the leakage current signal and the second status signal generated by the status detection circuit 50 to determine whether the leakage current protection circuit is functioning correctly. For example, when the first status signal is low and the second status signal is high, it indicates that a leakage current has occurred in the power line, and the leakage current protection circuit is effectively disconnected, indicating that the leakage current protection function is normal. When both the first and second status signals are low, it indicates that a leakage current has occurred in the power line, and the leakage current protection circuit has not disconnected, indicating that the leakage current protection function has failed. Using a leakage current protection circuit improves the reliability of leakage current protection for power lines.

[0072] Optional, Figure 3 This is a schematic diagram of another leakage current protection circuit provided in an embodiment of the present invention. Based on the above embodiments, as follows... Figure 3 As shown, the control switch 10 includes an electrically holding relay 11; the electrically holding relay includes an electromagnetic coil 111 and a relay switch 112, the relay switch 112 being connected in series with the power line.

[0073] The electromagnetic coil 111 is used to control the relay switch 112 to close when current flows through it, and to control the relay switch 112 to open when no current flows through it.

[0074] The leakage current protection drive circuit 40 includes: a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, and a third resistor R3; the control terminal of the first transistor Q1 is connected to the leakage current signal V through the first resistor R1. SCR-EN The first terminal of the first transistor Q1 is electrically connected to the control terminal of the second transistor Q2, and the second terminal of the first transistor Q1 is grounded; the control terminal of the second transistor Q2 is electrically connected to the control module 60 through the second resistor R2, the first terminal of the second transistor Q2 is electrically connected to the electromagnetic coil 111 of the electrically holding relay 11, and the second terminal of the second transistor Q2 is grounded; the third resistor R3 is electrically connected between the control terminal and the ground terminal of the second transistor Q2.

[0075] Specifically, the control switch 10 may include an electrically holding relay 11. The working state of the electrically holding relay 11 requires a continuous voltage holding. That is, when current continuously flows through the electromagnetic coil 111, the relay switch 112 is in the open state, and when the electromagnetic coil 111 is in the state of no current flowing through it, the relay switch 112 is in the closed state.

[0076] When a power line leakage occurs, the leakage detection circuit 20 generates a leakage signal V. SCR-EN The voltage is transmitted to the control terminal of the first transistor Q1, turning it on and subsequently lowering the voltage at the control terminal of the second transistor Q2, causing it to turn off. At this time, no current path is formed in the leakage protection drive circuit 40. Therefore, no current flows through the electromagnetic coil 111 of the electrically holding relay 11, and the electromagnetic coil 111 releases the engaged relay switch 112, causing the relay switch 112 to open, thus disconnecting the power line and achieving leakage protection. The first resistor R1 limits the current at the control terminal of the first transistor Q1, while the second and third resistors R2 limit the current at the control terminal of the second transistor Q2, ensuring that the voltage signals input to the control terminals of both transistors Q1 and Q2 are low-voltage signals, preventing the first and second transistors Q1 and Q2 from burning out.

[0077] It should be noted that, Figure 4 This is a schematic diagram of the control module of a leakage current protection circuit provided in an embodiment of the present invention. Figure 4 As shown, the control terminal of the second transistor Q2 is electrically connected to the X1 terminal of the control module 60. When the power line is not leaking current and is operating normally, the first transistor Q1 is in the off state, and the control module 60 continuously outputs a high-level signal to the control terminal of the second transistor Q2, keeping the second transistor Q2 in the on state. Therefore, a continuous current flows through the electromagnetic coil 111, the relay switch 112 is closed, and the power line is in the on state. When the control module 60 outputs a low-level signal to the control terminal of the second transistor Q2, the second transistor Q2 is in the off state. No current flows through the electromagnetic coil 111, the relay switch 112 is open, and the power line is in the off state. Thus, under the normal operating state of the power line, the level signal output from the X1 terminal of the control module 60 can be used to control the relay switch 112 to close or open.

[0078] When a power line leakage occurs, the control module 60 continues to output a voltage level signal to the control terminal of the second transistor Q2. The leakage signal turns on the first transistor Q1, thereby pulling down the voltage level signal output by the control module 60 to the control terminal of the second transistor Q2, causing Q2 to turn off. Therefore, no current flows through the electromagnetic coil 111, and the relay switch 112 opens, achieving leakage protection for the power line.

[0079] When the leakage fault in the power line is resolved, the leakage signal disappears, the first transistor Q1 is turned off, and the level signal continuously output by the control module 60 to the control terminal of the second transistor Q2 returns to a high level, thereby controlling the second transistor Q2 to conduct. A continuous current flows through the electromagnetic coil 111, and the relay switch 112 closes, restoring the power line to its initial conduction state.

[0080] Optionally, based on the above embodiments, combined with Figure 3 and Figure 4 The leakage current detection circuit 20 includes: a detection chip 21, a first thyristor VS1, a first diode D1, a fourth resistor R4, a fifth resistor R5, and a first capacitor C1.

[0081] The detection chip 21 is electrically connected to the gate of the current transformer L1 and the first thyristor VS1. The anode of the first thyristor VS1 is electrically connected to the first power supply through the fourth resistor R4. The cathode of the first thyristor VS1 is electrically connected to the anode of the first diode D1. The cathode of the first diode D1 is electrically connected to the reset circuit 30. The fifth resistor R5 is electrically connected between the anode of the first diode D1 and the ground terminal. The first capacitor C1 is connected in parallel between the gate of the first thyristor VS1 and the ground terminal. The detection chip 21 is used to drive the first thyristor VS1 to conduct according to the current signal output by the current transformer L1.

[0082] Specifically, a capacitor and a resistor are connected in parallel between the detection chip 21 and the current transformer L1 to amplify the voltage signal generated by the current transformer L1 and transmit it to the detection chip 21. Based on the received voltage signal, the detection chip 21 generates a trigger signal and transmits it to the gate of the first thyristor VS1. The anode of the first thyristor VS1 is continuously powered by a first power supply; therefore, the first thyristor VS1 is in a conducting state. For example, the first power supply is a 12V power supply. After the first thyristor VS1 is turned on, the first thyristor VS1, the first diode D1, and the reset circuit 30 form a current path, providing a voltage signal to the control terminal of the first transistor Q1, thus controlling the first transistor Q1 to conduct.

[0083] The fourth resistor R4 and the fifth resistor R5 are used to limit the current of the first thyristor VS1 and the first diode D1 to prevent excessive current in the circuit from damaging the first thyristor VS1 and the first diode D1. The first capacitor C1 is used to stabilize the voltage of the first thyristor VS1 and the first diode D1.

[0084] Optionally, based on the above embodiments, see also... Figure 3 and Figure 4 The reset circuit 30 includes: a third transistor Q3, a sixth resistor R6, a current limiting unit 31, a reset button 32, and a leakage current reporting unit 33.

[0085] The control terminal of the third transistor Q3 is electrically connected to the first power supply through the current limiting unit 31. The first terminal of the third transistor Q3 is electrically connected to the cathode of the first diode D1, and the second terminal of the third transistor Q3 is grounded. The first terminal of the third transistor Q3 is also electrically connected to the first power supply through the sixth resistor R6. The two ends of the reset button 32 are connected in parallel to the current limiting unit 31 and the ground terminal. The input terminal of the leakage current reporting unit 33 is electrically connected to the anode of the first diode D1, and the output terminal of the leakage current reporting unit 33 is electrically connected to the control module 60. The leakage current reporting unit 33 is used to transmit the leakage current signal V... SCR-EN The data is transmitted to the control module 60 so that the control module 60 can report the leakage status.

[0086] The first thyristor VS1, the first diode D1, and the first transistor Q1 form a circuit, and the leakage signal V SCR-EN This is the voltage at the anode of the first diode D1.

[0087] Specifically, the first power supply outputs a voltage signal to the control terminal of the third transistor Q3. The current limiting unit 31 limits the current, ensuring that the voltage signal received by the control terminal of the third transistor Q3 is a small voltage signal, thereby controlling the third transistor Q3 to remain in the conducting state. When a leakage current occurs in the power line, the first thyristor VS1, the first diode D1, and the third transistor Q3 form a current path, and the voltage at the anode of the first diode D1 is the leakage current signal V. SCR-EN Leakage signal V SCR-EN The signal is transmitted to the control terminal of the first transistor Q1, driving the leakage protection drive circuit 40 to activate and control the relay switch 112 to open, thus achieving leakage protection for the power line. The sixth resistor R6 limits the current to the collector of the third transistor Q3, protecting it from burning out.

[0088] When the reset button 32 is not in operation, it remains in the open state. After the leakage fault is cleared, the leakage protection circuit is reset by pressing and releasing the reset button 32. This activates the reset button 32, creating a current path between the first power supply, the current limiting unit 31, and the reset button 32. This restores the leakage protection circuit to its initial state, i.e., the power line is conducting. Consequently, the voltage signal at the control terminal of the third transistor Q3 disappears, turning off the third transistor Q3. This causes the first thyristor VS1 to turn off at zero crossing, eliminating the loop current between the first transistor Q1, the first diode D1, and the third transistor Q3. The voltage at the anode of the first diode D1 becomes zero. Therefore, the first transistor Q1 turns off, and the level signal at the control terminal of the second transistor Q2 converts to a high-level signal, turning on the second transistor Q2. Current flows through the electromagnetic coil 111, causing it to activate the relay switch 112. The relay switch 112 closes, the power line is conducting, and the initial state is restored. It should be noted that when resetting the leakage protection circuit after clearing the leakage fault, the leakage protection circuit returns to its initial state after pressing and releasing the reset button 32 once. Furthermore, since the current transformer L1 does not generate a leakage voltage signal, the leakage protection circuit remains in its initial state.

[0089] When the power line is operating normally, pressing and releasing the reset button 32 once sends an electrical signal to the X8 terminal of the control module 60, causing the X1 terminal of the control module 60 to output a low-level signal to the control terminal of the second transistor Q2, controlling the second transistor Q2 to turn off, thereby opening the relay switch 112 and disconnecting the power line. Pressing and releasing the reset button 32 again causes the X1 terminal of the control module 60 to output a high-level signal to the control terminal of the second transistor Q2, controlling the second transistor Q2 to turn on, thereby closing the relay switch 112 and connecting the power line, thus realizing the control of the power line's on / off state.

[0090] The leakage current reporting unit 33 reports the leakage current signal V based on the leakage current signal V. SCR-EN The corresponding level signal is obtained and transmitted to the control module 60, so that the control module 60 can receive the state of leakage in the power line, thereby facilitating processing and reporting the leakage state to the user end.

[0091] Optionally, based on the above embodiments, see also... Figure 3 and Figure 4 The state detection circuit 50 includes: an optocoupler 51, a seventh resistor R7, and a rectification and current limiting unit 52.

[0092] The rectification and current limiting unit 52 is electrically connected between the optocoupler 51 and the power line. The rectification and current limiting unit 52 is used to rectify the current in the power line and output the rectified current to the optocoupler 51.

[0093] The first output terminal of the optocoupler 51 is grounded, the second output terminal of the optocoupler 51 is electrically connected to the control module 60, and the seventh resistor R7 is electrically connected between the second output terminal of the optocoupler 51 and the second power supply.

[0094] Specifically, the rectification and current limiting unit 52 is connected in series with the power line, which can rectify the AC power of the power line into DC power and output it to the optocoupler 51, so that the light-emitting diode in the optocoupler 51 can light up normally. The rectification and current limiting unit 52 can also limit the current input to the optocoupler 51 to prevent the current input to the optocoupler 51 from being too large.

[0095] When there is no leakage in the power line, i.e., the power line is in a conducting state, the optocoupler 51 emits light and outputs current, and the seventh resistor R7 converts the voltage signal of the second power supply into a low-level signal, i.e., generates a second status signal, which is output to the control module 60. When there is a leakage in the power line, i.e., the power line is in a disconnected state, no current is input to the optocoupler 51, and the optocoupler 51 also has no output current. The seventh resistor R7 converts the voltage signal of the second power supply into a high-level signal, i.e., generates a second status signal, which is output to the control module 60. The control module 60 can determine whether the relay switch 112 is effectively disconnected when a leakage occurs based on the first status signal generated by the reset circuit 30 and the second status signal generated by the status detection circuit 50.

[0096] Based on the above embodiments, the working principle of the leakage current protection circuit using an electrically holding relay has been described in detail. The working process of the leakage current protection circuit using an electrically holding relay is as follows: When the current transformer L1 detects a leakage current in the power line, the leakage current detection circuit 20 generates a leakage current signal. The leakage current signal drives the first transistor Q1 in the leakage current protection drive circuit 40 to conduct, thereby pulling down the level signal output by the control module 60 to the control terminal of the second transistor Q2, causing the second transistor Q2 to turn off. Therefore, no current flows through the electromagnetic coil 111, and the relay switch 112 is opened, realizing leakage current protection for the power line. When the leakage current fault in the power line is cleared, pressing and releasing the reset button 32 turns it on, the leakage current signal disappears, the first transistor Q1 turns off, causing the level signal output by the control module 60 to the control terminal of the second transistor Q2 to rise, the second transistor Q2 turns on, a continuous current flows through the electromagnetic coil 111, the relay switch 112 closes, realizing the reset of the power line and restoring the power line to its initial state.

[0097] Leakage current protection circuits can use either electrically latching relays or magnetically latching relays. The following examples will explain the specific working principle of a leakage current protection circuit using a magnetically latching relay.

[0098] Optional, Figure 5This is a schematic diagram of another leakage current protection circuit provided in an embodiment of the present invention. Based on the above embodiments, as follows... Figure 5 As shown, the control switch 10 includes a magnetic latching relay 12; the magnetic latching relay includes a closing coil 121, a closing coil 122, and a relay switch 123, the relay switch 123 being connected in series with the power line; the closing coil 121 is used to control the relay switch 123 to close when current flows through it; the closing coil 122 is used to control the relay switch 123 to open when current flows through it.

[0099] The leakage protection drive circuit 40 includes: a fourth transistor Q4, a fifth transistor Q5, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11.

[0100] The control terminal of the fourth transistor Q4 is electrically connected to the control module 60 through the eighth resistor R8. The first terminal of the fourth transistor Q4 is electrically connected to the turn-off coil 122, and the leakage current detection circuit 20 is electrically connected between the first terminal of the fourth transistor Q4 and the turn-off coil 122. The second terminal of the fourth transistor Q4 is grounded. The control terminal of the fifth transistor Q5 is electrically connected to the control module 60 through the ninth resistor R9. The first terminal of the fifth transistor Q5 is electrically connected to the closed coil 121, and the second terminal of the fifth transistor Q5 is grounded. The tenth resistor R10 is electrically connected between the control terminal and the ground terminal of the fourth transistor Q4, and the eleventh resistor R11 is electrically connected between the control terminal and the ground terminal of the fifth transistor Q5.

[0101] Specifically, the control switch 10 may also include a magnetic latching relay 12. The magnetic latching relay 12 can be driven to a closed or open state by a pulse signal of a certain width, maintaining the corresponding state without requiring continuous current, thus reducing energy consumption. The magnetic latching relay 12 includes a closing coil 121 and a closing coil 122. When a pulse signal is input to the closing coil 121, the closing coil 121 conducts, controlling the relay switch 123 to close, and the power line is connected; when a pulse signal is input to the closing coil 122, the closing coil 122 conducts, controlling the relay switch 123 to open, and the power line is disconnected.

[0102] When a power line leakage occurs, the leakage detection circuit 20 generates a drive signal V. OFF The current is transmitted to the collector of the fourth transistor Q4, causing current to flow through the turn-off coil 122 and releasing the relay switch 123, disconnecting the power line and thus providing leakage protection for the power line. After the power line is disconnected, no current flows through the status detection circuit 50, the electrical signal at the control terminal of the third transistor Q3 in the reset circuit 30 disappears, and the second thyristor VS2 turns off at zero crossing, thereby causing the drive signal V generated by the leakage detection circuit 20 to be released. OFFThe current disappears. Therefore, no current flows through the turn-off coil 122, and the turn-off coil 122 is disconnected. Figure 6 This is a schematic diagram of the control module of another leakage current protection circuit provided in an embodiment of the present invention. Figure 6 As shown, the control terminal of the fifth transistor Q5 is electrically connected to the X5 terminal of the control module 60 through the ninth resistor R9. When the leakage fault in the power line is cleared, the leakage protection circuit is reset. The reset circuit 30 sends a reset signal to the X8 terminal of the control module 60, causing the X5 terminal of the control module 60 to send an electrical signal to the control terminal of the fifth transistor Q5, controlling the fifth transistor Q5 to conduct. This, in turn, turns on the closed coil 121, driving the relay switch 123 to close. The eighth resistor R8, the ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11 are used to limit the current of the fourth transistor Q4 and the fifth transistor Q5, preventing excessive current from entering the fourth transistor Q4 and the fifth transistor Q5 and burning them out.

[0103] It should be noted that the control terminal of the fourth transistor Q4 is electrically connected to the X4 terminal of the control module 60 through the eighth resistor R8. During normal operation of the power line, the power line can be switched on or off using the reset button 32. When the reset button 32 is pressed and released once, the control module 60 sends a high-level signal to the control terminal of the fourth transistor Q4, controlling Q4 to conduct, thereby turning on the off-coil 122 and driving the relay switch 123 to open. When the reset button 32 is pressed and released again, the control module 60 sends a high-level signal to the control terminal of the fifth transistor Q5, controlling Q5 to conduct, thereby turning on the closing coil 121 and driving the relay switch 123 to close.

[0104] Optionally, based on the above embodiments, combined with Figure 5 and Figure 6 As shown, the leakage current detection circuit 20 includes: a detection chip 21, a second thyristor VS2, a first diode D1, a twelfth resistor R12, and a second capacitor C2.

[0105] The detection chip 21 is electrically connected to the gate of the current transformer L1 and the second thyristor VS2. The anode of the second thyristor VS2 is electrically connected to the first terminal of the fourth transistor Q4. The cathode of the second thyristor VS2 is electrically connected to the anode of the first diode D1. The cathode of the first diode D1 is electrically connected to the reset circuit 30. The twelfth resistor R12 is electrically connected between the cathode of the second thyristor VS2 and the ground terminal. The second capacitor C2 is connected in parallel between the gate of the second thyristor VS2 and the ground terminal. The detection chip 21 is used to drive the second thyristor VS2 to conduct according to the current signal output by the current transformer L1.

[0106] Specifically, the circuit connections of the leakage detection circuit 20 in the leakage protection circuit using the magnetic latching relay 12 and the leakage detection circuit 20 in the leakage protection circuit using the electrically latching relay 11 are the same as those described in the above embodiments and will not be repeated here. The difference is that the anode of the second thyristor VS2 is electrically connected to the collector of the fourth transistor Q4. When a leakage occurs in the power line, the detection chip 21 triggers the second thyristor VS2 to conduct, and the anode of the second thyristor VS2 outputs a drive signal V. OFF The current flows to the collector of the fourth transistor Q4, driving the turn-off coil 122 to conduct, and the relay switch 123 to open, thereby disconnecting the power line. After the power line is disconnected, no current flows through the status detection circuit 50, the electrical signal at the control terminal of the third transistor Q3 in the reset circuit 30 disappears, and the second thyristor VS2 turns off at zero crossing, thereby causing the drive signal V generated by the leakage current detection circuit 20 to be released. OFF The current disappears. Therefore, no current flows through the turn-off coil 122, and the turn-off coil 122 is disconnected. Among them, the twelfth resistor R12 is used to limit the current flowing through the second thyristor VS2, and the second capacitor C2 is used to stabilize the pressure of the second thyristor VS2 and the first diode D1.

[0107] Optionally, based on the above embodiments, see also... Figure 5 and Figure 6 The reset circuit 30 includes: a third transistor Q3, a thirteenth resistor R13, a current limiting unit 31, a reset button 32, and a leakage current reporting unit 33.

[0108] The control terminal of the third transistor Q3 is electrically connected to the state detection circuit 50 through the current limiting unit 31. The first terminal of the third transistor Q3 is electrically connected to the cathode of the first diode D1, and the second terminal of the third transistor Q3 is grounded. The first terminal of the third transistor Q3 is also electrically connected to the first power supply through the thirteenth resistor R13. The two ends of the reset button 32 are connected in parallel to the current limiting unit 31 and the ground terminal. The input terminal of the leakage current reporting unit 33 is electrically connected to the anode of the first diode D1, and the output terminal of the leakage current reporting unit 33 is electrically connected to the control module 60. The leakage current reporting unit 33 is used to transmit the leakage current signal V. SCR-EN The data is transmitted to the control module 60 so that the control module 60 can report the leakage status.

[0109] Specifically, when the state detection circuit 50 is turned on, i.e., when the power line is in its initial state or when a power line leakage occurs and the leakage protection circuit has not yet executed leakage protection, the state detection circuit 50 outputs an electrical signal to the control terminal of the third transistor Q3, controlling the third transistor Q3 to be in the on state. When the leakage protection drive circuit 40 controls the turn-off coil 122 to turn on, and the power line is disconnected, no current flows through the state detection circuit 50. Therefore, the third transistor Q3 is turned off, breaking the circuit path formed by the second thyristor VS2, the first diode D1, and the third transistor Q3. The second thyristor VS2 is turned off, the voltage at the anode of the second thyristor VS2 disappears, no current flows through the turn-off coil 122, and the relay switch 123 remains in the off state. The current limiting unit 31 in the leakage protection circuit using the magnetic latching relay 12 has the same function as the current limiting unit 31 in the leakage protection circuit using the electrically latching relay 11, and has been described in the above embodiments, so it will not be repeated here.

[0110] After the leakage fault is cleared, the reset button 32 can be pressed to restore the leakage protection circuit to its initial state, and the power line will be connected. Specifically, after the leakage fault in the power line is cleared, pressing the reset button 32 once sends a reset signal to the X8 terminal of the control module 60, which causes the X5 terminal of the control module 60 to output a level signal to the control terminal of the fifth transistor Q5, controlling the fifth transistor Q5 to conduct, allowing the pulse current to flow through the closed coil 121, driving the relay switch 123 to close, the power line to be connected, the fault indicator light to go out, and the power line to be restored to its initial state.

[0111] It should be noted that when the power line is operating normally, the reset button 32 is used to control the control switch 10 to close or open, thereby controlling the closure or opening of the power line. For example, when the power line is operating normally, pressing the reset button 32 once will disconnect the power line; pressing the reset button again will close the power line.

[0112] Optionally, based on the above embodiments, see also... Figure 5 and Figure 6 The status detection circuit 50 includes: an optocoupler 51, a rectification and current limiting unit 52, a sixth transistor Q6, and a fourteenth resistor R14.

[0113] The rectification and current limiting unit 52 is electrically connected between the optocoupler 51 and the power line. The rectification and current limiting unit 52 is used to rectify the current in the power line and output the rectified current to the optocoupler 51.

[0114] The second output terminal of the optocoupler 51 is electrically connected to the first power supply. The first output terminal of the optocoupler 51 is electrically connected to the control terminal of the sixth transistor Q6 through the fourteenth resistor R14. The first terminal of the sixth transistor Q6 is electrically connected to the control module 60, and the second terminal of the sixth transistor Q6 is grounded.

[0115] Specifically, the rectification and current limiting unit 52 in the leakage protection circuit of the magnetic latching relay 12 has the same function as the rectification and current limiting unit 52 in the leakage protection circuit of the electrically latching relay 11, and has been described in the above embodiments, so it will not be repeated here. The output voltage signal V1 of the second output terminal of the optocoupler 51 is output to the current limiting unit 31 in the reset circuit 30, and is transmitted to the control terminal of the third transistor Q3 through the current limiting unit 31.

[0116] When the power line is in its initial state or when a leakage occurs and the leakage protection action is not activated, the second output terminal of the optocoupler 51 outputs a voltage signal V1, which controls the third transistor Q3 to conduct, thereby enabling the leakage protection circuit to respond quickly, execute the leakage protection action, and disconnect the power line. Furthermore, the second output terminal of the optocoupler 51 outputs a voltage signal V1, which controls the sixth transistor Q6 to conduct, thereby causing the output terminal of the status detection circuit 50 to output a low-level signal, i.e., the second status signal, to the X3 terminal of the control module 60.

[0117] When the power line is in leakage protection mode, there is no current in the power line, no voltage signal is output from the second output terminal of optocoupler 51, the third transistor Q3 is turned off, there is no current in the leakage protection circuit, and the power line can maintain the leakage protection state. Since there is no voltage signal output from the second output terminal of optocoupler 51, the sixth transistor Q6 is turned off, and the output terminal of the state detection circuit 50 outputs a high-level signal, that is, the second state signal, to the X3 terminal of the control module 60.

[0118] Based on the above embodiments, the working principle of the leakage protection circuit using a magnetic latching relay has been described in detail. The working process of the leakage protection circuit using a magnetic latching relay is as follows: When a leakage occurs in the power line, the leakage detection circuit 20 generates a drive signal V. OFF The current is transmitted to the collector of the fourth transistor Q4, causing a pulse current to flow through the turn-off coil 122, releasing the relay switch 123, and realizing leakage protection for the power line. When the leakage fault in the power line is cleared, pressing and releasing the reset button 32 causes the X5 terminal of the control module 60 to send an electrical signal to the control terminal of the fifth transistor Q5, controlling the fifth transistor Q5 to conduct, thereby causing a pulse current to flow through the closed coil 121, turning on the closed coil 121, driving the relay switch 123 to close, and realizing the reset of the leakage protection circuit.

[0119] Optionally, based on the above embodiments, see also... Figure 3 or Figure 5 The current limiting unit 31 includes: a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17.

[0120] The fifteenth resistor R15 is electrically connected between the control terminal of the third transistor Q3 and the reset button 32; the sixteenth resistor R16 and the seventeenth resistor R17 are connected in series between the first power supply and the ground terminal, or the sixteenth resistor R16 and the seventeenth resistor R17 are connected in series between the first output terminal of the optocoupler 51 and the ground terminal.

[0121] Specifically, for the leakage current protection circuit using the electrically holding relay 11, see [link to relevant documentation]. Figure 3 The first power supply provides a voltage signal to the control terminal of the third transistor Q3 through the current limiting unit 31, controlling the third transistor Q3 to remain continuously conducting when the reset button 32 is not pressed. The fifteenth resistor R15, the sixteenth resistor R16, and the seventeenth resistor R17 can limit the current input to the third transistor Q3 to prevent excessive current from burning out the third transistor Q3.

[0122] For leakage protection circuits using magnetic latching relay 12, see [link / reference]. Figure 5 When the power line is in the on state, the second output terminal of the optocoupler 51 provides a voltage signal V1 to the control terminal of the third transistor Q3 through the current limiting unit 31, controlling the third transistor Q3 to conduct. When the power line is in the off state, there is no current output from the second output terminal of the optocoupler 51, and the third transistor Q3 is off. Similarly, the fifteenth resistor R15, the sixteenth resistor R16, and the seventeenth resistor R17 can limit the current input to the third transistor Q3 to prevent excessive current from burning out the third transistor Q3.

[0123] Optionally, based on the above embodiments, see also... Figure 3 or Figure 5 The leakage current reporting unit 33 includes: the seventh transistor Q7 and the eighteenth resistor R18.

[0124] The control terminal of the seventh transistor Q7 is electrically connected to the anode of the first diode D1 through the eighteenth resistor R18. The first terminal of the seventh transistor Q7 is electrically connected to the control module 60, and the second terminal of the seventh transistor Q7 is grounded.

[0125] Specifically, when a power line leakage occurs, a leakage signal is output to the control terminal of the seventh transistor Q7, causing Q7 to conduct. Based on the leakage signal, the eighteenth resistor R18 reduces the voltage signal of the second power supply to a low-level signal and outputs the low-level signal to the X2 terminal of the control module 60. The control module 60 can determine that a power line leakage has occurred based on the low-level signal received at the X2 terminal, and control the leakage protection drive circuit 40 to disconnect the relay switch.

[0126] After the power line is reset, there is no voltage signal at the anode of the first diode D1, and the seventh transistor Q7 is in the off state. The leakage signal disappears, and the eighteenth resistor R18 outputs a high-level signal from the second power supply to the X2 terminal of the control module 60. The control module 60 can determine that the leakage fault in the power line has been cleared based on the high-level signal received at the X2 terminal, and then closes the relay switch by controlling the leakage protection drive circuit 40.

[0127] Optionally, based on the above embodiments, see also... Figure 3 or Figure 5 The rectification and current limiting unit 52 includes: a varistor VR1, a second diode D2, a third capacitor C3, at least one nineteenth resistor R19 and a twentieth resistor R20.

[0128] A varistor VR1 is connected in series with the power line; the anode of the second diode D2 is connected to the second input terminal of the optocoupler 51, and the cathode of the second diode D2 is connected to one end of the varistor VR1; at least one nineteenth resistor R19 and a twentieth resistor R20 are connected in series with the other end of the varistor VR1 and the first input terminal of the optocoupler 51; a third capacitor C3 is connected in parallel with the twentieth resistor R20 and the second input terminal of the optocoupler 51.

[0129] Specifically, the varistor VR1 is used to detect the voltage connected to the power line, preventing excessive voltage in the input status detection circuit 50 from damaging it. The second diode D2 is used to rectify the AC power connected to the power line, allowing only unidirectional current input to the optocoupler 51, enabling the optocoupler 51 to emit light normally. At least one nineteenth resistor R19 and a twentyth resistor R20 are used to limit the current input to the optocoupler 51, protecting it from burnout. For example, Figure 3 or Figure 5 The diagram shows the rectifier and current limiting unit 52 including two nineteenth resistors R19. The third capacitor C3 is used to stabilize the voltage at the input of the optocoupler 51.

[0130] Optionally, based on the above embodiments, see also... Figure 3 or Figure 5The leakage protection circuit also includes a status indicator circuit 70; the status indicator circuit 70 includes a first light-emitting diode LED1, a second light-emitting diode LED2, a twenty-first resistor R21, and a twenty-second resistor R22.

[0131] The anode of the first light-emitting diode LED1 is electrically connected to the control module 60 through the twenty-first resistor R21; the anode of the second light-emitting diode LED2 is electrically connected to the control module 60 through the twenty-second resistor R22; the cathodes of the first light-emitting diode LED1 and the second light-emitting diode LED2 are both grounded.

[0132] Specifically, the first LED (LED1) is electrically connected to terminal X6 of the control module 60, and the second LED (LED2) is electrically connected to terminal X7 of the control module 60. LED1 indicates the network connection status of the leakage current protection circuit, and LED2 indicates the status of the power line and the operating status of the leakage current protection circuit. For example, when the control module 60 reports a leakage current status or a fault in the leakage current protection device to the user end, LED1 illuminates, indicating that the network connection status is normal. The illumination rules for LED1 are not limited here. When the control module 60 receives a level signal from the reset circuit 30 based on the leakage current signal, if the level signal is low, the control module 60 can control LED2 to illuminate to indicate a leakage current in the power line at the user end. When the control module 60 receives a leakage current signal from the leakage current detection circuit 20 and a second status signal from the status detection circuit 50, it can control LED2 to illuminate to indicate whether the leakage current protection device at the user end is functioning normally. The illumination rules for LED2 are not limited here.

[0133] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A leakage current protection circuit, characterized in that, include: Control switch, leakage current detection circuit, reset circuit and leakage current protection drive circuit; The control switch is connected in series with the power line; The leakage current detection circuit is electrically connected to a current transformer installed on the power line. The leakage current detection circuit is used to generate a leakage current signal when the power line is detected to have leakage current based on the output of the current transformer. The leakage protection drive circuit is electrically connected to the leakage detection circuit and the control switch. When the leakage signal is continuously received, the leakage protection drive circuit drives the control switch to disconnect and maintain the disconnected state. The reset circuit is connected to the leakage current detection circuit and is used to reset the leakage current detection circuit in order to reset the leakage current protection drive circuit. When the power line is operating normally, the user can control the control switch to close or open by triggering the reset circuit; The leakage detection circuit generates a leakage signal when a leakage occurs in the power line and outputs the leakage signal to the leakage protection drive circuit. The leakage protection drive circuit controls the control switch to open according to the leakage signal, thereby realizing leakage protection of the power line. After the power line leakage is cleared, the user triggers the reset circuit to eliminate the leakage signal, and the leakage protection drive circuit drives the control switch to close, restoring the power line to its initial state. The leakage protection circuit further includes: a control module; the leakage protection drive circuit is electrically connected to the control module; when no leakage occurs in the power line, the control module controls the leakage protection drive circuit to open or close the control switch; when leakage occurs in the power line, the control module cannot close the control switch by controlling the leakage protection drive circuit.

2. The circuit according to claim 1, characterized in that, It also includes: a status detection circuit; The status detection circuit is electrically connected to the power line and the control module. The status detection circuit is used to detect whether the control switch performs the corresponding leakage protection action and output a second status signal to the control module. The control module determines whether the control switch is effectively disconnected based on the leakage signal and the second status signal.

3. The circuit according to claim 1, characterized in that, The control switch includes an electrically holding relay; the electrically holding relay includes an electromagnetic coil and a relay switch, the relay switch being connected in series with a power line. The electromagnetic coil is used to control the relay switch to close when current flows through it, and to control the relay switch to open when no current flows through it. The leakage protection drive circuit includes: a first transistor, a second transistor, a first resistor, a second resistor, and a third resistor; The control terminal of the first transistor is connected to the leakage signal through the first resistor. The first terminal of the first transistor is electrically connected to the control terminal of the second transistor, and the second terminal of the first transistor is grounded. The control terminal of the second transistor is electrically connected to the control module through the second resistor. The first terminal of the second transistor is electrically connected to the electromagnetic coil of the electrically holding relay, and the second terminal of the second transistor is grounded. The third resistor is electrically connected between the control terminal and the ground terminal of the second transistor.

4. The circuit according to claim 3, characterized in that, The leakage current detection circuit includes: a detection chip, a first thyristor, a first diode, a fourth resistor, a fifth resistor, and a first capacitor; The detection chip is electrically connected to the current transformer and the gate of the first thyristor. The anode of the first thyristor is electrically connected to the first power supply through the fourth resistor. The cathode of the first thyristor is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the reset circuit. The fifth resistor is electrically connected between the anode of the first diode and the ground terminal. The first capacitor is connected in parallel between the gate of the first thyristor and the ground terminal. The detection chip is used to drive the first thyristor to conduct according to the current signal output by the current transformer.

5. The circuit according to claim 4, characterized in that, The reset circuit includes: a third transistor, a sixth resistor, a current limiting unit, a reset button, and a leakage current reporting unit; The control terminal of the third transistor is electrically connected to the first power supply through the current limiting unit. The first terminal of the third transistor is electrically connected to the cathode of the first diode. The second terminal of the third transistor is grounded, and the first terminal of the third transistor is electrically connected to the first power supply through the sixth resistor. The two ends of the reset button are connected in parallel to the current limiting unit and the ground terminal. The input terminal of the leakage current reporting unit is electrically connected to the anode of the first diode, and the output terminal of the leakage current reporting unit is electrically connected to the control module. The leakage current reporting unit is used to transmit the leakage current signal to the control module so that the control module reports the leakage current status. The first thyristor, the first diode, and the first transistor form a circuit, and the leakage signal is the voltage at the anode of the first diode.

6. The circuit according to claim 5, characterized in that, The status detection circuit includes: an optocoupler, a seventh resistor, and a rectification and current limiting unit; The rectification and current limiting unit is electrically connected between the optocoupler and the power line. The rectification and current limiting unit is used to rectify the current in the power line and output the rectified current to the optocoupler. The first output terminal of the optocoupler is grounded, the second output terminal of the optocoupler is electrically connected to the control module, and the seventh resistor is electrically connected between the second output terminal of the optocoupler and the second power supply.

7. The circuit according to claim 1, characterized in that, The control switch includes a magnetic latching relay; the magnetic latching relay includes a closing coil, a closing coil, and a relay switch, the relay switch being connected in series with the power line; the closing coil is used to control the relay switch to close when current flows through it; the closing coil is used to control the relay switch to open when current flows through it. The leakage protection drive circuit includes: a fourth transistor, a fifth transistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor; The control terminal of the fourth transistor is electrically connected to the control module through the eighth resistor. The first terminal of the fourth transistor is electrically connected to the turn-off coil, and the leakage current detection circuit is electrically connected between the first terminal of the fourth transistor and the turn-off coil. The second terminal of the fourth transistor is grounded. The control terminal of the fifth transistor is electrically connected to the control module through the ninth resistor. The first terminal of the fifth transistor is electrically connected to the closed coil, and the second terminal of the fifth transistor is grounded. The tenth resistor is electrically connected between the control terminal and the ground terminal of the fourth transistor, and the eleventh resistor is electrically connected between the control terminal and the ground terminal of the fifth transistor.

8. The circuit according to claim 7, characterized in that, The leakage current detection circuit includes: a detection chip, a second thyristor, a first diode, a twelfth resistor, and a second capacitor; The detection chip is electrically connected to the current transformer and the gate of the second thyristor. The anode of the second thyristor is electrically connected to the first terminal of the fourth transistor. The cathode of the second thyristor is electrically connected to the anode of the first diode. The cathode of the first diode is electrically connected to the reset circuit. The twelfth resistor is electrically connected between the cathode of the second thyristor and the ground terminal. The second capacitor is connected in parallel between the gate of the second thyristor and the ground terminal. The detection chip is used to drive the second thyristor to conduct according to the current signal output by the current transformer.

9. The circuit according to claim 8, characterized in that, The reset circuit includes: a third transistor, a thirteenth resistor, a current limiting unit, a reset button, and a leakage current reporting unit; The control terminal of the third transistor is electrically connected to the status detection circuit through the current limiting unit. The first terminal of the third transistor is electrically connected to the cathode of the first diode, the second terminal of the third transistor is grounded, and the first terminal of the third transistor is electrically connected to the first power supply through the thirteenth resistor. The two ends of the reset button are connected in parallel to the current limiting unit and the ground terminal. The input terminal of the leakage current reporting unit is electrically connected to the anode of the first diode, and the output terminal of the leakage current reporting unit is electrically connected to the control module. The leakage current reporting unit is used to transmit the leakage current signal to the control module so that the control module reports the leakage current status.

10. The circuit according to claim 9, characterized in that, The state detection circuit includes: an optocoupler, a rectification and current limiting unit, a sixth transistor, and a fourteenth resistor; The rectification and current limiting unit is electrically connected between the optocoupler and the power line. The rectification and current limiting unit is used to rectify the current in the power line and output the rectified current to the optocoupler. The second output terminal of the optocoupler is electrically connected to the first power supply, the first output terminal of the optocoupler is electrically connected to the control terminal of the sixth transistor through the fourteenth resistor, the first terminal of the sixth transistor is electrically connected to the control module, and the second terminal of the sixth transistor is grounded.

11. The circuit according to claim 6 or 10, characterized in that, The current limiting unit includes: a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor; The fifteenth resistor is electrically connected between the control terminal of the third transistor and the reset button; The sixteenth resistor and the seventeenth resistor are connected in series between the first power supply and the ground terminal, or... The sixteenth resistor and the seventeenth resistor are connected in series between the first output terminal and the ground terminal of the optocoupler.

12. The circuit according to claim 6 or 10, characterized in that, The leakage current reporting unit includes: a seventh transistor and an eighteenth resistor; The control terminal of the seventh transistor is electrically connected to the anode of the first diode through the eighteenth resistor, the first terminal of the seventh transistor is electrically connected to the control module, and the second terminal of the seventh transistor is grounded.

13. The circuit according to claim 6 or 10, characterized in that, The rectification and current limiting unit includes: a varistor, a second diode, a third capacitor, at least one nineteenth resistor and a twentyth resistor; The varistor is connected in series with the power line; the anode of the second diode is connected to the second input terminal of the optocoupler, and the cathode of the second diode is connected to one end of the varistor; at least one nineteenth resistor and the twentieth resistor are connected in series with the other end of the varistor and the first input terminal of the optocoupler; the third capacitor is connected in parallel with the twentieth resistor and the second input terminal of the optocoupler.

14. The circuit according to claim 1, characterized in that, Also includes: Status indicator circuit; The status indication circuit includes: a first light-emitting diode, a second light-emitting diode, a twenty-first resistor, and a twenty-second resistor; The anode of the first LED is electrically connected to the control module through the 21st resistor; the anode of the second LED is electrically connected to the control module through the 22nd resistor; the cathodes of both the first and second LEDs are grounded.

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