Automatic testing circuit and testing method for leakage protection function

Abstract

A leakage protection function automatic inspection circuit and inspection method, comprising a current transformer, a simulated leakage current module, a leakage detection processing module, a rectifier module, a trip coil, a controllable device control module and a control unit module; generating a simulated leakage current only on a simulated half-wave of the main circuit alternating current, wherein the simulated half-wave is a positive half-wave or a negative half-wave of the main circuit alternating current; limiting the current used to drive the trip coil to operate on the simulated half-wave of the main circuit alternating current, so that the current on the simulated half-wave cannot drive the trip coil to operate, and the current on the non-simulated half-wave can drive the trip coil to operate; monitoring a signal that triggers the trip coil to operate after generating the simulated leakage current, if a signal that triggers the trip coil to operate is monitored, the leakage protection function is normal, otherwise the leakage protection function is abnormal, and the leakage protection function can be automatically and regularly inspected without affecting the normal use of the circuit.

Description

Technical Field

[0001] The invention relates to the field of leakage protectors, and in particular to an automatic inspection circuit and inspection method for leakage protection functions. Background Art

[0002] With the construction of smart grid, the safety of electricity use has been paid more and more attention by the state and society, and users have gradually required the protection switch to have leakage protection function. The general requirements for leakage current protectors (GB-26829-2008) point out that the leakage protector should have a test device to simulate a leakage current not exceeding the preset current size under the rated voltage, so as to regularly test the action ability of the residual current protection device.

[0003] In actual practice, a test button is usually set on the surface of the leakage current protector. When the test button is triggered, it can be considered that the leakage protection scenario that needs to be activated is simulated. Generally, the leakage current protector requires the test button to be manually triggered once a month to ensure the long-term stable operation of the leakage current protector, so that it can be activated in time when the leakage protection scenario actually occurs. However, the detection method of manually triggering the test button once a month has low operability, causing the leakage current protector to be in a potentially unsafe working state. In addition, when the above-mentioned test method for testing the action capacity of the residual current protection device is carried out, power interruption will occur. In some important power consumption places, power interruption is not allowed. The existing method of testing the action capacity of the residual current protection device has certain limitations in practical applications.

[0004] To this end, a protection circuit that can automatically check whether the leakage protection switch is working normally and does not need to interrupt the power supply during the test can improve the reliability of the product, make the use of electricity safer, and has high value. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide an automatic inspection circuit and inspection method for leakage protection function with wide application range and high electricity safety.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A leakage protection function automatic inspection circuit, comprising a current transformer, a leakage current simulation module, a leakage detection processing module, a rectifier module, a tripping coil, a controllable device control module and a control unit module;

[0008] The current transformer and the rectifier module are both connected to the main circuit, the simulated leakage current module is coupled with the current transformer, the rectifier module forms a trip coil loop with the trip coil through the controllable device control module, and the leakage detection processing module is respectively connected with the current transformer and the controllable device control module;

[0009] The control unit module is connected to the analog leakage current module, and controls the analog leakage current module to generate an analog leakage current only on the analog half-wave, wherein the analog half-wave is the positive half-wave or negative half-wave of the main circuit alternating current. After the leakage detection processing module detects the leakage current signal through the current transformer, the controllable device control module is triggered to act to turn on the trip coil circuit. The controllable device control module is connected to the control unit module, and the action signal is fed back to the control unit module. The current rectified by the rectifier module cannot drive the trip coil to act in the analog half-wave, but can drive the trip coil to act in the non-analog half-wave.

[0010] Furthermore, the simulated leakage current module includes at least one resistor for current limiting, a unidirectional conductive device and a second controllable device, and the two ends of the resistor, the unidirectional conductive device and the second controllable device are connected in series to the main circuit to generate a simulated leakage current that is only on the simulated half-wave.

[0011] Furthermore, the rectifier module includes multiple diodes and at least one current-limiting resistor, and the multiple diodes and the current-limiting resistor are connected to form a rectifier circuit for limiting the current of the simulated half-wave, so that the current on the simulated half-wave cannot drive the tripping coil to operate, and the current on the non-simulated half-wave can drive the tripping coil to operate.

[0012] Furthermore, the control unit module includes an MCU chip U1, which is used to control the analog leakage current module to generate a positive half-wave or negative half-wave analog leakage current and to receive a feedback signal from a controllable device control module. After controlling the analog leakage current module to generate an analog leakage current, the MCU chip U1 determines whether the leakage protection function is working normally by receiving the feedback signal from the controllable device control module.

[0013] Furthermore, the controllable device control module includes a controllable device connected in the loop of the rectifier circuit and the trip coil, a feedback circuit connected to the controllable device, a control end of the controllable device connected to the leakage detection processing module, the leakage detection processing module controls the controllable device to turn on the loop of the trip coil, and the feedback circuit is connected to the control unit module to feed back the action signal of the controllable device to the control unit module.

[0014] Furthermore, it also includes a voltage stabilizing circuit module for providing power to the control unit module and the leakage detection processing module. The input end of the voltage stabilizing circuit module is connected to the rectifier module, and the output end is connected to the control unit module and the leakage detection processing module.

[0015] Furthermore, the simulated leakage current module includes a resistor R7, a diode D11 and a second controllable device D10. After the resistor R7, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the N-phase line on one side of the current transformer, and the second controllable device D10 is connected to the L-phase line on the other side of the current transformer through the resistor R7; the rectifier module includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8 and a current limiting resistor R3; when the input voltage is a positive half-wave, the loop formed by the diode D4 and the diode D8 is turned on; when the input voltage is a negative half-wave, the loop formed by the diode D5, the diode D7 and the current limiting resistor R3 is turned on.

[0016] Furthermore, the simulated leakage current module includes a resistor R7, a diode D11 and a second controllable device D10. After the resistor R7, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the L phase line on one side of the current transformer, and the second controllable device D10 is connected to the N phase line on the other side of the current transformer through the resistor R7; the rectifier module includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8 and a current limiting resistor R3; when the input voltage is a negative half-wave, the loop formed by the diode D5 and the diode D7 is turned on; when the input voltage is a positive half-wave, the loop formed by the diode D4, the diode D8 and the current limiting resistor R3 is turned on.

[0017] Further, the controllable device control module includes a feedback circuit consisting of a resistor R4, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a capacitor C9, a thyristor V1 as a controllable device, a resistor R5 and a capacitor C2, one end of the resistor R5 and one end of the capacitor C2 are connected to the control electrode of the thyristor V1, the control electrode of the thyristor V1 is connected to the leakage detection processing module, one end of the resistor R4 is connected to the anode of the thyristor V1, and the anode of the thyristor V1 is connected to the rectifier module through the tripping coil; the other end of the resistor R4 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to one end of the resistor R12, the other end of the resistor R12, one end of the resistor R14 and one end of the capacitor C9 are connected to one end of the resistor R13, the other end of the resistor R13 is connected to the control unit module, and the other end of the resistor R14, the other end of the capacitor C9 and the cathode of the thyristor V1 are connected to GND.

[0018] Further, the leakage detection processing module includes a leakage chip U2, a resistor R8, a bidirectional TVS tube D9, a resistor R6, a resistor R10, a capacitor C3, a capacitor C4 and a capacitor C8; one end of the two TVS tubes D9 after being reverse-parallel connected, one end of the resistor R6 and one end of the resistor R8 are connected to one end of the current transformer, the other end of the two TVS tubes D9 after being reverse-parallel connected, one end of the resistor R10 and the other end of the resistor R8 are connected to the other end of the current transformer, the other end of the resistor R6, one end of the capacitor C3 and one end of the capacitor C4 are connected to the leakage chip U2, the other end of the resistor R10, one end of the capacitor C8 and the other end of the capacitor C4 are connected to the leakage chip U2, and the other end of the capacitor C3 and the other end of the capacitor C8 are connected to GND; the leakage chip U2 is connected to the controllable device control module for controlling the action of the controllable device control module.

[0019] A method for automatically checking a leakage protection function generates a simulated leakage current that is only located on a simulated half-wave of a main circuit alternating current, wherein the simulated half-wave is a positive half-wave or a negative half-wave of the main circuit alternating current; the current used to drive a trip coil to operate is limited on the simulated half-wave of the main circuit alternating current, so that the current on the simulated half-wave cannot drive the trip coil to operate, while the current on a non-simulated half-wave can drive the trip coil to operate; after the simulated leakage current is generated, a signal that triggers the trip coil to operate is monitored; if a signal that triggers the trip coil to operate is monitored, the leakage protection function is normal, otherwise the leakage protection function is abnormal.

[0020] The present invention discloses an automatic inspection circuit for leakage protection function, which generates a positive half-wave or negative half-wave simulated leakage current under the control of a control unit module through a simulated leakage current module, a current transformer senses the simulated leakage current and drives a controllable device control module to operate through a leakage detection processing module, and after the controllable device control module operates, a feedback signal is transmitted to the control unit module to complete the automatic inspection, but the trip coil is not operated during this process; while the current transformer senses the simulated leakage current, the rectifier module rectifies the current on the corresponding simulated half-wave into a smaller current so that the trip coil cannot trip and cut off the power, therefore, during the entire automatic inspection process, the trip coil will not trip and cut off the power, and the staff is no longer required to manually operate the test button during the entire process, thereby improving the reliability and power safety of the product and improving the application value.

[0021] In addition, the simulated leakage current generated by the simulated leakage current module is a positive half-wave voltage or a negative half-wave voltage, which is rectified into a small current that cannot drive the trip coil to trip after passing through a rectification circuit formed by multiple diodes and at least one current limiting resistor. The leakage current generated by the leakage of the main line includes both a positive half-wave voltage and a negative half-wave current, and can still drive the trip coil to trip after rectification by the rectification circuit.

[0022] The automatic inspection method for leakage protection function of the present invention can realize automatic and regular inspection of leakage protection function (such as once a month), but the tripping coil will not be activated during this process, and the normal use of the circuit will not be affected. When a leakage fault occurs, the tripping protection can be performed normally, thereby improving the reliability and electricity safety of the product and improving the application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of an automatic inspection circuit for leakage protection function of the present invention;

[0024] Figure 2 It is a circuit diagram of an automatic inspection circuit for leakage protection function of the present invention (first embodiment);

[0025] Figure 3 It is a circuit diagram of an automatic inspection circuit for leakage protection function of the present invention (second embodiment);

[0026] Figure 4 It is a circuit diagram of a rectifier module in an automatic inspection circuit for leakage protection function of the present invention;

[0027] Figure 5 It is a circuit diagram of a leakage current simulation module in an automatic inspection circuit for leakage protection function of the present invention;

[0028] Figure 6 This is a circuit diagram of a voltage stabilizing circuit module in an automatic inspection circuit for leakage protection function of the present invention:

[0029] Figure 7 It is a circuit diagram of a leakage detection processing module in an automatic inspection circuit for leakage protection function of the present invention;

[0030] Figure 8 It is a circuit diagram of a controllable device control module in an automatic inspection circuit for leakage protection function of the present invention;

[0031] Fig. 9 The invention discloses a circuit diagram of a control unit module in an automatic inspection circuit for leakage protection function. DETAILED DESCRIPTION

[0032] The following is combined with Figures 1 to 9 The given embodiments further illustrate the specific implementation of the automatic inspection circuit and inspection method of the leakage protection function of the present invention. The automatic inspection circuit and inspection method of the leakage protection function of the present invention are not limited to the description of the following embodiments.

[0033] A leakage protection function automatic inspection circuit, comprising a current transformer, a leakage current simulation module, a leakage detection processing module, a rectifier module, a tripping coil, a controllable device control module and a control unit module;

[0034] The current transformer and the rectifier module are both connected to the main circuit, the simulated leakage current module is coupled with the current transformer, the rectifier module forms a trip coil loop with the trip coil through the controllable device control module, and the leakage detection processing module is respectively connected with the current transformer and the controllable device control module;

[0035] The control unit module is connected to the analog leakage current module, and controls the analog leakage current module to generate an analog leakage current only on the analog half-wave, wherein the analog half-wave is the positive half-wave or negative half-wave of the main circuit alternating current. After the leakage detection processing module detects the leakage current signal through the current transformer, the controllable device control module is triggered to act to turn on the trip coil circuit. The controllable device control module is connected to the control unit module, and the action signal is fed back to the control unit module. The current rectified by the rectifier module cannot drive the trip coil to act in the analog half-wave, but can drive the trip coil to act in the non-analog half-wave.

[0036] The present invention discloses an automatic inspection circuit for leakage protection function, which generates a positive half-wave or negative half-wave simulated leakage current under the control of a control unit module through a simulated leakage current module, a current transformer senses the simulated leakage current and drives a controllable device control module to operate through a leakage detection processing module, and after the controllable device control module operates, a feedback signal is transmitted to the control unit module to complete the automatic inspection, but the trip coil is not operated during this process; while the current transformer senses the simulated leakage current, the rectifier module rectifies the current on the corresponding simulated half-wave into a smaller current so that the trip coil cannot trip and cut off the power, therefore, during the entire automatic inspection process, the trip coil will not trip and cut off the power, and the staff is no longer required to manually operate the test button during the entire process, thereby improving the reliability and power safety of the product and improving the application value.

[0037] Combination Figure 1-3 As shown, a leakage protection function automatic inspection circuit includes a current transformer, a simulated leakage current module, a leakage detection processing module, a rectifier module, a trip coil, a controllable device control module and a control unit module. The current transformer and the rectifier module are both connected to the main circuit, the simulated leakage current module is connected to both sides of the current transformer, the rectifier module is connected to the trip coil through the controllable device control module to form a trip coil loop, and the leakage detection processing module is connected to the current transformer and the controllable device control module respectively.

[0038] The current transformer is used to sense leakage and generate a leakage current signal. The leakage detection processing module is used to process the leakage current signal and transmit an action signal to the controllable device control module to activate the controllable device control module, turn on the circuit of the tripping coil, and then trigger the tripping coil to trip the switch to cut off the main circuit to achieve leakage protection. This is the prior art in the field.

[0039] The simulated leakage current module is used to generate simulated leakage current. The improvement of the present invention is that the simulated leakage current generated by the simulated leakage current module is only located on the simulated half-wave of the main circuit AC, and the simulated half-wave is the positive half-wave or negative half-wave of the main circuit AC, that is, the simulated leakage current is only located on the positive half-wave of the main circuit AC, or only on the negative half-wave of the main circuit AC. The rectifier module rectifies the main circuit AC, and the rectified current is current-limited in the simulated half-wave, so that the trip coil cannot be driven to operate in the simulated half-wave, but the current in the non-simulated half-wave can drive the trip coil to operate. When the main circuit has the simulated leakage current generated by the simulated leakage current module, the controllable device control module acts to conduct the circuit of the trip coil, and the rectifier module cannot drive the trip coil to trigger the trip. When an actual leakage fault occurs in the main circuit, the leakage fault signal will exist in both the simulated half-wave and the non-simulated half-wave. In the non-simulated half-wave, the rectifier module drives the trip coil to trigger the trip, thereby realizing leakage protection.

[0040] The control unit module is connected to the simulated leakage current module, and is used to periodically control the simulated leakage current module to generate a simulated leakage current that is only located on the simulated half-wave. At the same time, the controllable device control module is connected to the control unit module to feed back an action signal to the control unit module. When the control unit module controls the simulated leakage current module to generate a simulated leakage current, and receives an action signal fed back by the controllable device control module, it is considered that the automatic leakage inspection is completed, and the leakage protection function is normal, and the tripping coil will not operate during the entire automatic inspection process, ensuring the power demand of the main line. When the control unit module controls the simulated leakage current module to generate a simulated leakage current, and does not detect an action signal fed back by the controllable device control module, it is considered that the leakage protection function is abnormal.

[0041] Further, if Figure 1 As shown, the automatic inspection circuit of the leakage protection function of the present invention also includes a voltage stabilizing circuit module, which is used to provide power to the control unit module and the leakage detection processing module. The input end of the voltage stabilizing circuit module is connected to the rectifier module, and the output end is connected to the control unit module and the leakage detection processing module. Obviously, a separate power supply circuit can also be set as needed, connected to the main circuit, and used to provide power to the control unit module, the leakage detection processing module, and other modules of the automatic inspection circuit of the leakage protection function. All of them belong to the protection scope of the present invention. Further, the control unit module also includes an alarm unit, which alarms when an abnormal leakage protection function is detected. The alarm unit can be an indicator light, or a buzzer, etc. Of course, according to other functional requirements, the automatic inspection circuit of the leakage protection function of the present invention can also include other modules.

[0042] The following, combined Figure 1 ,as well as Figure 2 A first embodiment is provided, Figure 3 The second embodiment provided further illustrates the automatic inspection circuit of the leakage protection function of the present invention. Figure 2 In the first embodiment, the simulated leakage current is a negative half-wave current, which occurs in the negative half-wave of the main circuit alternating current. The simulated half-wave is the negative half-wave of the main circuit alternating current, and the non-simulated half-wave is the positive half-wave. Figure 3 In the second embodiment, the simulated leakage current is a positive half-wave current, which occurs in the positive half-wave of the main circuit alternating current. The simulated half-wave is the positive half-wave of the main circuit alternating current, and the non-simulated half-wave is the negative half-wave.

[0043] In this example, the control unit module preferably includes an MCU chip U1, which is used to control the analog leakage current module to generate a positive half-wave or negative half-wave analog leakage current and to receive a feedback signal from the controllable device control module. After the MCU chip U1 controls the analog leakage current module to generate the analog leakage current, it receives the feedback signal from the controllable device control module to determine whether the leakage protection function is working properly. The MCU chip U1 can be a microprocessor, a single-chip microcomputer or other chips.

[0044] In this example, the simulated leakage current module preferably includes at least one resistor for current limiting, a unidirectional conductive device and a second controllable device, and the two ends of the resistor, the unidirectional conductive device and the second controllable device are connected in series and connected to the main circuit, and are used to generate simulated leakage current only in the positive half-wave or negative half-wave. The positive half-wave or negative half-wave that generates the simulated leakage current is the simulated half-wave, and the corresponding negative half-wave or positive half-wave that does not generate the simulated leakage current is the non-simulated half-wave. The control end of the second controllable device is connected to the control unit module, wherein the unidirectional conductive device is preferably a diode, and the second controllable device is preferably an optocoupler. Of course, transistors and MOS tubes can also be used.

[0045] In this example, the rectifier module preferably includes a plurality of diodes and at least one current limiting resistor, and the plurality of diodes and the current limiting resistor are connected to form a rectifier circuit for limiting the current of the simulated half-wave, so that the current on the simulated half-wave cannot drive the trip coil to operate, and the current on the non-simulated half-wave can drive the trip coil to operate. The rectifier circuit rectifies the simulated leakage current of the simulated half-wave into a small current that cannot drive the trip coil to operate under the current limiting effect of the current limiting resistor, and when an actual leakage fault occurs in the main circuit (simulated leakage generated by the non-simulated leakage current generating circuit), since the leakage current includes both the positive half-wave and the negative half-wave leakage current, although the current of the simulated half-wave (positive half-wave or negative half-wave) of the main circuit is rectified by the rectifier circuit into a small current that cannot cause the trip coil to operate, the current of the non-simulated half-wave (negative half-wave or positive half-wave) can still drive the trip coil to operate after passing through the rectifier circuit, so that it will not trip when the leakage protection function is automatically tested, but can trip normally when an actual leakage fault occurs.

[0046] In this example, the controllable device control module preferably includes a controllable device connected in the loop of the rectifier circuit and the trip coil, a feedback circuit connected to the controllable device, a control end of the controllable device connected to the leakage detection processing module, the leakage detection processing module controls the controllable device to turn on the loop of the trip coil, the feedback circuit is connected to the control unit module, and the action signal of the controllable device is fed back to the control unit module to feed back whether the controllable device is turned on. When the control unit module controls the simulated leakage current module to generate a simulated leakage current, based on the signal of the feedback circuit, it is determined whether the automatic inspection of the leakage protection function is normal or abnormal, and the trip coil will not be operated during the entire automatic inspection process to ensure the power demand of the main line.

[0047] The simulated leakage current module is connected to the Lout and Nout lines of the main circuit on both sides of the current transformer. Preferably, the simulated leakage current module is connected to the main circuit through a non-core zero-sequence transformer.

[0048] Combination Figure 2 , 4 5 specifically illustrate the simulated leakage current module and the rectifier module of the first embodiment. In this embodiment, the simulated leakage current module generates a simulated leakage current of a negative half-wave, and the rectifier module is used to limit the negative half-wave current.

[0049] The simulated leakage current module includes a current limiting resistor R7, a diode D11 as a unidirectional conductive device and a second controllable device D10. After the resistor, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the N-phase line on one side of the current transformer, and the second controllable device D10 is connected to the L-phase line on the other side of the current transformer through the resistor R7.

[0050] like Figure 2 , 5 As shown, the simulated leakage current module includes a second controllable device D10, a resistor R9, a diode D11 and a resistor R7, the first pin of the second controllable device D10 is connected to one end of the resistor R9, the other end of the resistor R9 is connected to the control unit module, specifically connected to the CTR pin of the MCU chip U1 of the control unit module, for receiving the control signal of the control unit module, the second pin of the second controllable device D10 is connected to GND, the third pin of the second controllable device D10 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the L phase line on one side near the current transformer, the fourth pin of the second controllable device D10 is connected to the cathode of the diode D11, the anode of the diode D11 is connected to the N phase line on the other side near the current transformer, that is, one end of the resistor R7 and the anode of the diode D11 are respectively connected to the Lout and Nout lines on both sides of the current transformer. Preferably, the second controllable device D10 is an optocoupler.

[0051] Combination Figure 2 ,4 As shown, a connection mode of simulating leakage current of the negative half-wave current limiting of the rectifier module is provided, and the rectifier module includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8 and a current limiting resistor R3. When the input voltage is a positive half-wave, the loop formed by the diode D4 and the diode D8 is turned on; when the input voltage is a negative half-wave, the loop formed by the diode D5, the diode D7 and the current limiting resistor R3 is turned on. Due to the action of the current limiting resistor R3, the output voltage and current after rectification are relatively small.

[0052] Specifically, Figure 2 , 4 As shown, the rectifier module includes a varistor VR1, a diode D4, a diode D5, a diode D7, a diode D8 and a current limiting resistor R3, one end of the varistor VR1, an anode of the diode D4 and a cathode of the diode D7 are connected to the L phase line, the other end of the varistor VR1, an anode of the diode D5 and a cathode of the diode D8 are connected to the N phase line, the cathode of the diode D5 is connected to one end of the current limiting resistor R3, the anode of the diode D7 and the anode of the diode D8 are connected to GND, and the other end of the current limiting resistor R3 and the cathode of the diode D4 are connected to the tripping coil.

[0053] Its working principle is: when the control unit module sends a high-level signal to the analog leakage current module, after the resistor R9 receives the high-level signal, the second controllable device D10 is turned on. In view of the unidirectional conduction characteristics of the diode D11, the current can only return to the L phase line from the N phase line through the diode D11, the second controllable device D10, and the resistor R7, thereby generating a negative half-wave simulated leakage current. The current loop of the negative half-wave simulated leakage current will not pass through the current transformer, but will induce a negative half-wave leakage current signal on the secondary side of the current transformer, and then the controllable device control module will be activated through the leakage detection processing module to make the trip coil loop conductive. However, the voltage and current output by the negative half-wave simulated leakage current after passing through the rectifier module are small, which is not enough to activate the trip coil. At the same time, the controllable device control module transmits a feedback signal to the control unit module, thereby completing the inspection process.

[0054] like Figure 2 , 3 As shown in FIG8 , the controllable device control module includes a controllable device for connecting with the rectifier module and the tripping coil to form a tripping coil loop, and a feedback circuit connected to the controllable device. Preferably, the controllable device is a thyristor V1, and the feedback circuit includes a voltage divider circuit formed by a resistor R4, a resistor R11, a resistor R12, a resistor R14, a resistor R13 and a capacitor C9. The control unit module obtains whether the controllable device is turned on by detecting the voltage divider circuit.

[0055] Specific as Figure 8As shown, the controllable device control module includes a resistor R4, a resistor R5, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a capacitor C2, a capacitor C9 and a thyristor V1. The thyristor V1 is used as a controllable device. One end of the resistor R5 and one end of the capacitor C2 are connected to the control electrode of the thyristor V1. The control electrode of the thyristor V1 is connected to the leakage detection processing module. Figure 2 , 3 As shown in , 8, the leakage detection processing module includes a leakage chip U2, the control electrode of the thyristor V1 is connected to the fifth pin of the leakage chip U2; one end of the resistor R4 is connected to the anode of the thyristor V1, and the anode of the thyristor V1 is connected to the rectifier module through the tripping coil; the other end of the resistor R4 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to one end of the resistor R12, the other end of the resistor R12, one end of the resistor R14 and one end of the capacitor C9 are connected to one end of the resistor R13, the other end of the resistor R13 is connected to the control unit module, and the other end of the resistor R14, the other end of the capacitor C9 and the cathode of the thyristor V1 are connected to GND. The principle is as follows: after the thyristor V1 receives the action signal from the leakage detection processing module, the thyristor V1 is turned on, so that the control unit module receives the feedback signal from the controllable device control module. The control unit module detects the voltage on the voltage divider resistor in the controllable device control module as a feedback signal. When the thyristor V1 is in the cut-off state, the control unit module detects a continuous high level on the voltage divider resistor; when the thyristor V1 is in the on state, the voltage difference across the thyristor V1 is close to 0V, and the control unit module detects a continuous low level on the voltage divider resistor.

[0056] like Figure 2 , 3 As shown in Figure 6, the voltage stabilizing circuit module includes a diode D1, a resistor R2, a capacitor C1 and a voltage stabilizing diode D3. The anode of the diode D1 is connected to the rectifier module through the trip coil, the cathode of the diode D1 is connected to one end of the resistor R2, and the other end of the resistor R2 and the cathode of the voltage stabilizing diode D3 are connected to one end of the capacitor C1 and serve as power supply ends to respectively power the control unit module and the leakage detection processing module. Figure 6 The power supply end is connected to a pin of the MCU chip U1 of the control unit module and the eighth pin of the leakage chip U2 of the leakage detection processing module to realize power supply, and the anode of the voltage regulator diode D3 and the other end of the capacitor C1 are connected to GND.

[0057] like Figure 2 , 3As shown in Figure 7, the leakage detection processing module is connected to the secondary side of the current transformer through the signal input interface J1. The leakage detection processing module includes a leakage chip U2, a resistor R8, a bidirectional TVS tube D9, a resistor R6, a resistor R10, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7 and a capacitor C8. The leakage signal induced by the current transformer is input through the interface J1, and passes through the sampling resistor R8. The bidirectional TVS tube D9 is connected in series with the resistors R6 and R10 respectively, and the other ends of the resistors R6 and R10 are connected to the second and third pins of the leakage chip U2 respectively. The sampling resistor R8 and the bidirectional TVS tube D9 are connected in parallel with the signal input interface J1. Specifically, one end of the two TVS tubes D9 connected in reverse parallel, one end of the resistor R6 and one end of the resistor R8 are connected to one end of the signal input interface J1, the other end of the two TVS tubes D9 connected in reverse parallel, one end of the resistor R10 and the other end of the resistor R8 are connected to the other end of the signal input interface J1, the other end of the resistor R6, one end of the capacitor C3 and one end of the capacitor C4 are connected to the second pin of the leakage chip U2, the other end of the resistor R10, one end of the capacitor C8 and the other end of the capacitor C4 are connected to the third pin of the leakage chip U2, the other end of the capacitor C3 and the other end of the capacitor C8 are connected to GND; the fourth pin of the leakage chip U2 is connected to GND, and the fifth pin of the leakage chip U2 is connected to the controllable device control module for controlling the action of the controllable device control module, as shown in the following figure. Figure 7 As shown, the control electrode of the thyristor V1 in the controllable device control module is connected to drive the thyristor V1 to conduct and complete the action process, the sixth pin of the leakage chip U2 is connected to one end of the capacitor C7, the seventh pin of the leakage chip U2 is connected to one end of the capacitor C5, the eighth pin of the leakage chip U2 is connected to the power supply end of the voltage stabilizing circuit module and one end of the capacitor C6, and the other end of the capacitor C6, the other end of the capacitor C7 and the other end of the capacitor C8 are connected to GND. Its working principle is: the leakage current signal induced by the current transformer generates a voltage signal through the resistor R8, and the voltage signal is input into the leakage chip U2 through the filter circuit composed of the resistor R6, the resistor R10, the capacitor C3, the capacitor C4 and the capacitor C8 for signal processing, and then the leakage chip U2 will output an action signal to the thyristor V1 in the controllable device control module. Obviously, the leakage detection processing circuit of the present invention can also adopt the existing conventional leakage detection circuit, without using the leakage chip U2, which detects the leakage signal of the circuit transformer and sends a trigger signal to the controllable device and the control circuit.

[0058] Combination Figure 3A second embodiment of a simulated leakage current module and a rectifier module is provided. The principle is the same as that of the first embodiment. In this example, the simulated leakage current module generates a simulated leakage current of a positive half-wave. The rectifier module includes multiple diodes and at least one current-limiting resistor. The multiple diodes and the current-limiting resistor are connected to form a rectifier circuit for limiting the positive half-wave voltage. Under the current-limiting effect of the current-limiting resistor, the rectifier circuit rectifies the simulated leakage current of the positive half-wave into a small current that cannot drive the trip coil to operate. When an actual leakage fault occurs in the main circuit (simulated leakage current generated by a non-simulated leakage current generating circuit), since the leakage current includes both the positive half-wave and negative half-wave leakage currents, although the leakage current of the positive half-wave is rectified into a smaller current by the rectifier circuit, the leakage current of the negative half-wave can still drive the trip coil to operate after passing through the rectifier circuit.

[0059] Similar to the first embodiment, the simulated leakage current module includes a resistor R7, a diode D11 and a second controllable device D10. After the resistor R7, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the L phase line on one side of the current transformer, and the second controllable device D10 is connected to the N phase line on the other side of the current transformer through the resistor R7.

[0060] The analog leakage current module includes a second controllable device D10, a resistor R9, a diode D11 and a resistor R7. The first pin of the second controllable device D10 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the control unit module, specifically connected to the CTR pin of the MCU chip U1 of the control unit module, for receiving the control signal of the control unit module. The second pin of the second controllable device D10 is connected to GND, the third pin of the second controllable device D10 is connected to one end of the resistor R7, and the other end of the resistor R7 is connected to the N-phase line on one side near the current transformer. The fourth pin of the second controllable device D10 is connected to the cathode of the diode D11, and the anode of the diode D11 is connected to the L-phase line end on the other side near the current transformer, that is, one end of the resistor R7 and the anode of the diode D11 are respectively connected to the Nout and Lout lines on both sides of the current transformer.

[0061] The rectifier module is specifically shown in Figure 3, and includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8, and a current-limiting resistor R3. When the input voltage is a negative half-wave, the loop formed by the diode D5 and the diode D7 is turned on; when the input voltage is a positive half-wave, the loop formed by the diode D4, the diode D8, and the current-limiting resistor R3 is turned on. Due to the action of the current-limiting resistor R3, the output voltage and current after rectification are relatively small.

[0062] Specific as Figure 3As shown, the rectifier module includes a varistor VR1, a diode D4, a diode D5, a diode D7, a diode D8 and a current limiting resistor R3, one end of the varistor VR1, an anode of the diode D4 and a cathode of the diode D7 are connected to the L phase line, the other end of the varistor VR1, an anode of the diode D5 and a cathode of the diode D8 are connected to the N phase line, the cathode of the diode D4 is connected to one end of the current limiting resistor R3, the anode of the diode D7 and the anode of the diode D8 are connected to GND, and the other end of the current limiting resistor R3 and the cathode of the diode D5 are connected to the tripping coil.

[0063] Its working principle is: when the control unit module sends a high-level signal to the analog leakage current module, after the resistor R9 receives the high-level signal, the second controllable device D10 is turned on. In view of the unidirectional conduction characteristics of the diode D11, the current can only return to the N-phase line from the L-phase line through the diode D11, the second controllable device D10, and the resistor R7, thereby generating a positive half-wave simulated leakage current. The current loop of the positive half-wave simulated leakage current will not pass through the current transformer, but will induce a positive half-wave leakage current signal on the secondary side of the current transformer, and then the controllable device control module will be activated through the leakage detection processing module to activate the trip coil loop conductor. However, the voltage and current output by the positive half-wave simulated leakage current after passing through the rectifier module are small, which is not enough to activate the trip coil. At the same time, the controllable device control module transmits a feedback signal to the control unit module, thereby completing the automatic inspection process.

[0064] Combination Figure 2 , 3 It can be seen that the leakage detection processing module, the voltage stabilizing circuit module, and the controllable device control module in the above two embodiments are the same, and the current transformer is preferably a zero-sequence transformer.

[0065] The present invention also provides an automatic inspection method for leakage protection function, which generates a simulated leakage current only on the simulated half-wave of the main circuit alternating current, wherein the simulated half-wave is the positive half-wave or the negative half-wave of the main circuit alternating current; the current used to drive the trip coil action is limited on the simulated half-wave of the main circuit alternating current, so that the current on the simulated half-wave cannot drive the trip coil action, and the current on the non-simulated half-wave can drive the trip coil action; after the simulated leakage current is generated, the signal that triggers the trip coil action is monitored, and if the signal that triggers the trip coil action is monitored, it means that the leakage protection function is normal, otherwise it means that the leakage protection function is abnormal. Since the current used to drive the trip coil action is limited on the simulated half-wave, the trip coil will not trip and cut off the power after receiving the signal that triggers the trip coil action in the case of simulated leakage current, and when an actual leakage fault occurs in the main circuit, the leakage fault signal will exist on both the simulated half-wave and the non-simulated half-wave, and the trip coil will still normally drive the trip coil to trigger the tripping after receiving the signal that triggers the trip coil action in the non-simulated half-wave, thereby realizing leakage protection.

[0066] The automatic inspection method for leakage protection function of the present invention can realize automatic and regular inspection of leakage protection function (such as once a month), but the tripping coil will not be activated during this process, and the normal use of the circuit will not be affected. When a leakage fault occurs, the tripping protection can be performed normally, thereby improving the reliability and electricity safety of the product and improving the application value.

[0067] The protection circuit for realizing the automatic inspection method of the leakage protection function of the present invention is implemented as follows: Figure 1-9 As shown, the positive half-wave or negative half-wave on the main circuit generates a simulated leakage current, and the simulated leakage current causes the current sensor set on the main circuit for sensing leakage to induce a leakage current signal. After being processed, the leakage current signal causes the trip coil circuit connected to the main circuit to be turned on. The simulated leakage current is limited in the trip coil circuit in the corresponding simulated half-wave and cannot cause the trip coil to trip. The automatic inspection is completed by detecting the feedback signal output to the outside by the trip coil circuit. When a leakage fault occurs in the main circuit, the leakage current causes the current sensor set on the main circuit for sensing leakage to induce a leakage current signal. After being processed, the trip coil circuit connected to the main circuit is turned on. The leakage current is not limited in the non-simulated half-wave, so that the trip coil circuit can still cause the trip coil to trip.

[0068] Obviously, the automatic inspection method of the leakage protection function of the present invention may not be limited to the above-mentioned embodiments. For example, the signal for monitoring the action of the triggering tripping coil may also be set at the monitoring leakage monitoring processing module to see whether it sends a signal to control the controllable device control module. Of course, the signal for monitoring the action of the triggering tripping coil is set closer to the position of the triggering tripping coil to trip, the better. The functions of periodically triggering to generate simulated leakage signals and determining whether the leakage protection function is normal can be implemented by means of a program using the MCU chip U1 as in the embodiment, or by means of a hardware circuit. The leakage monitoring processing function and the way in which the controllable device controls the triggering tripping coil can be adjusted as needed, and all belong to the protection scope of the present invention.

[0069] Furthermore, based on the automatic inspection method of the leakage protection function of the present invention, a high-level signal for generating a simulated leakage current on the main circuit is periodically output through software, and the feedback signal that triggers the tripping coil action is collected and monitored within a certain period of time; if the feedback signal that triggers the tripping coil action is monitored, the leakage protection function is normal, otherwise the leakage protection function is abnormal, and an alarm can be issued to prompt the user. Specifically, when the embodiment of the present invention is monitored, if the feedback signal is monitored as a low-level signal, the leakage protection function automatically works normally; if the feedback signal is a high-level signal, the leakage protection function works abnormally.

[0070] Specifically described in detail in combination with the above two embodiments, the control unit module outputs a high-level signal to the analog leakage current module. Within a certain period of time, the control unit module collects and detects the feedback signal transmitted by the controllable device control module. If the control unit module detects that the feedback signal is a low-level signal, the leakage protection function automatically checks that the circuit function is normal; if the control unit module detects that the feedback signal is a high-level signal, the leakage protection function automatically checks that the circuit function is abnormal. Preferably, the control unit module includes an alarm unit, and when it is detected that the leakage protection function automatically checks that the circuit function is abnormal, the alarm unit sounds an alarm. Preferably, the alarm unit includes an LED light controlled by the control unit module. When the leakage protection function automatically checks that the circuit function is abnormal, the LED light is always on as an alarm signal. Figure 2 , 3 It can be seen that the LED lamp is connected to the MCU chip U1.

[0071] like Fig. 9As shown, the control unit module includes an alarm unit, and the alarm unit includes a resistor R1 and a light emitting diode D2. One end of the resistor R1 is connected to a pin of the MCU chip U1, and the other end of the resistor R1 is connected to the anode of the light emitting diode D2. The cathode of the light emitting diode is connected to GND. When the automatic inspection circuit of the leakage protection function fails or fails, the light emitting diode D2 emits light to alarm. Whether the automatic inspection circuit of the leakage protection function is normal is judged by the feedback signal output by the controllable device control module to the control unit module, that is, after the simulated leakage current is generated, the control unit module continuously receives the high level output by the controllable device control module, which can be judged as the automatic inspection circuit of the leakage protection function failing or failing.

[0072] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A leakage protection function automatic testing circuit, characterized in that: It includes a current transformer, a leakage current simulation module, a leakage detection processing module, a rectifier module, a trip coil, a controllable device control module and a control unit module; The current transformer and the rectifier module are both connected to the main circuit, the simulated leakage current module is coupled with the current transformer, the rectifier module forms a trip coil loop with the trip coil through the controllable device control module, and the leakage detection processing module is respectively connected with the current transformer and the controllable device control module; The control unit module is connected to the analog leakage current module, and controls the analog leakage current module to generate an analog leakage current only on the analog half-wave, wherein the analog half-wave is the positive half-wave or negative half-wave of the main circuit alternating current. After the leakage detection processing module detects the leakage current signal through the current transformer, the controllable device control module is triggered to act to turn on the trip coil circuit. The controllable device control module is connected to the control unit module, and the action signal is fed back to the control unit module. The current rectified by the rectifier module cannot drive the trip coil to act in the analog half-wave, but can drive the trip coil to act in the non-analog half-wave.

2. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The simulated leakage current module includes at least one resistor for current limiting, a unidirectional conductive device and a second controllable device. The two ends of the resistor, the unidirectional conductive device and the second controllable device are connected in series to the main circuit to generate a simulated leakage current that is only located on the simulated half-wave.

3. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The rectifier module includes multiple diodes and at least one current-limiting resistor. The multiple diodes and the current-limiting resistor are connected to form a rectifier circuit for limiting the current of the simulated half-wave, so that the current on the simulated half-wave cannot drive the trip coil to operate, and the current on the non-simulated half-wave can drive the trip coil to operate.

4. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The control unit module includes an MCU chip U1, which is used to control the analog leakage current module to generate a positive half-wave or negative half-wave analog leakage current and to receive a feedback signal from a controllable device control module. After controlling the analog leakage current module to generate the analog leakage current, the MCU chip U1 determines whether the leakage protection function is working normally by receiving the feedback signal from the controllable device control module.

5. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The controllable device control module includes a controllable device connected in the loop of the rectifier circuit and the trip coil, a feedback circuit connected to the controllable device, a control end of the controllable device connected to the leakage detection processing module, the leakage detection processing module controls the controllable device to conduct the loop of the trip coil, and the feedback circuit is connected to the control unit module to feed back the action signal of the controllable device to the control unit module.

6. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: It also includes a voltage stabilizing circuit module for providing power to the control unit module and the leakage detection processing module. The input end of the voltage stabilizing circuit module is connected to the rectifier module, and the output end is connected to the control unit module and the leakage detection processing module.

7. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The simulated leakage current module includes a resistor R7, a diode D11 and a second controllable device D10. After the resistor R7, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the N-phase line on one side of the current transformer, and the second controllable device D10 is connected to the L-phase line on the other side of the current transformer through the resistor R7; The rectifier module includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8 and a current-limiting resistor R3; when the input voltage is a positive half-wave, the loop formed by the diode D4 and the diode D8 is turned on; when the input voltage is a negative half-wave, the loop formed by the diode D5, the diode D7 and the current-limiting resistor R3 is turned on.

8. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The simulated leakage current module includes a resistor R7, a diode D11 and a second controllable device D10. After the resistor R7, the diode D11 and the second controllable device D10 are connected in series, the anode of the diode D11 is connected to the L phase line on one side of the current transformer, and the second controllable device D10 is connected to the N phase line on the other side of the current transformer through the resistor R7; The rectifier module includes a full-bridge rectifier circuit composed of a diode D4, a diode D5, a diode D7, a diode D8 and a current-limiting resistor R3; when the input voltage is a negative half-wave, the loop formed by the diode D5 and the diode D7 is turned on; when the input voltage is a positive half-wave, the loop formed by the diode D4, the diode D8 and the current-limiting resistor R3 is turned on.

9. The automatic testing circuit for leakage protection function according to claim 5, characterized in that: The controllable device control module includes a feedback circuit composed of a resistor R4, a resistor R11, a resistor R12, a resistor R13, a resistor R14 and a capacitor C9, a thyristor V1 as a controllable device, a resistor R5 and a capacitor C2, one end of the resistor R5 and one end of the capacitor C2 are connected to the control electrode of the thyristor V1, the control electrode of the thyristor V1 is connected to the leakage detection processing module, one end of the resistor R4 is connected to the anode of the thyristor V1, and the anode of the thyristor V1 is connected to the rectifier module through a tripping coil; the other end of the resistor R4 is connected to one end of the resistor R11, the other end of the resistor R11 is connected to one end of the resistor R12, the other end of the resistor R12, one end of the resistor R14 and one end of the capacitor C9 are connected to one end of the resistor R13, the other end of the resistor R13 is connected to the control unit module, and the other end of the resistor R14, the other end of the capacitor C9 and the cathode of the thyristor V1 are connected to GND.

10. The automatic testing circuit for leakage protection function according to claim 1, characterized in that: The leakage detection processing module includes a leakage chip U2, a resistor R8, a bidirectional TVS tube D9, a resistor R6, a resistor R10, a capacitor C3, a capacitor C4 and a capacitor C8; one end of the two TVS tubes D9 after being reversely connected in parallel, one end of the resistor R6 and one end of the resistor R8 are connected to one end of the current transformer, the other end of the two TVS tubes D9 after being reversely connected in parallel, one end of the resistor R10 and the other end of the resistor R8 are connected to the other end of the current transformer, the other end of the resistor R6, one end of the capacitor C3 and one end of the capacitor C4 are connected to the leakage chip U2, the other end of the resistor R10, one end of the capacitor C8 and the other end of the capacitor C4 are connected to the leakage chip U2, and the other end of the capacitor C3 and the other end of the capacitor C8 are connected to GND; the leakage chip U2 is connected to the controllable device control module for controlling the action of the controllable device control module.

11. A method for automatically testing leakage protection function, characterized in that: Generate a simulated leakage current that is only located on the simulated half-wave of the main circuit AC power, wherein the simulated half-wave is the positive half-wave or negative half-wave of the main circuit AC power; limit the current used to drive the trip coil on the simulated half-wave of the main circuit AC power, so that the current on the simulated half-wave cannot drive the trip coil to operate, and the current on the non-simulated half-wave can drive the trip coil to operate; after generating the simulated leakage current, monitor the signal that triggers the trip coil to operate, if the signal that triggers the trip coil to operate is monitored, the leakage protection function is normal, otherwise the leakage protection function is abnormal.

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