A leakage protection circuit for automatic monitoring of leakage protection devices

Abstract

The invention discloses a leakage protection circuit for automatic monitoring of a leakage protection device, comprising a control circuit and a tripping coil for tripping and powering off the leakage protection device, wherein the control circuit is connected to a zero-sequence mutual inductor for detecting zero-live line leakage of the leakage protection device and detecting simulated leakage, an automatic simulated leakage circuit for sending simulated leakage signals to the zero-sequence mutual inductor during a negative half cycle of a power supply voltage phase, a tripping coil detection circuit for detecting whether the tripping coil voltage is normal, a thyristor (SCR) for controlling the tripping coil to trip and power off when zero-live line leakage occurs, a thyristor (SCR) detection circuit for detecting whether the thyristor (SCR) operates normally when a simulated leakage signal is detected, and a fault warning lamp circuit for alarming when the tripping coil or the thyristor (SCR) cannot operate normally, and a leakage protection device with long-term power supply, which can automatically and regularly monitor the leakage protection function of the leakage protection device.

Description

[Technical field]

[0001] The invention relates to a leakage protection circuit which can be used for automatic monitoring of a leakage protection device. [Background Technology]

[0002] At present, in order to verify whether the leakage protection function of the leakage protection devices on the domestic market is normal, such as leakage protection plugs and leakage protection socket lamps, the instructions for use clearly state that the user needs to manually press the test button to verify whether the leakage protection function is normal before use, or manually press the test button once a month to verify whether the leakage protection function is normal. Although the instructions propose a verification method, there are generally the following defects:

[0003] 1. Not all users have a sense of safety protection, and most people will not press the test button to verify the leakage protection function.

[0004] 2. Even if users are aware of this, they are unable to regularly check whether the leakage protection plug is functioning normally. There is a possibility that the leakage protection plug has lost its protection function but is still in use, which is very likely to cause safety accidents. [Summary of the invention]

[0005] The present invention overcomes the shortcomings of the above-mentioned technology and provides a leakage protection circuit with automatic monitoring function used in a leakage protection device.

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

[0007] A leakage protection circuit for automatic monitoring of a leakage protection device comprises a control circuit 1 and a tripping coil 2 for tripping and powering off the leakage protection device, wherein the control circuit 1 is connected to a zero-sequence transformer 3 for detecting zero-live leakage of the leakage protection device and detecting simulated leakage, an automatic simulated leakage circuit 4 for sending a simulated leakage signal to the zero-sequence transformer 3 during the negative half cycle of the power supply voltage phase, a tripping coil detection circuit 5 for detecting whether the voltage of the tripping coil 2 is normal, a thyristor SCR for controlling the tripping coil 2 to trip and power off when there is leakage of the zero-live wire, a thyristor SCR detection circuit 6 for detecting whether the thyristor SCR is working normally when the simulated leakage signal is detected, and a fault warning lamp circuit 7 for alarming when the tripping coil 2 or the thyristor SCR cannot work normally.

[0008] As described above, a leakage protection circuit that can be automatically monitored for use in a leakage protection device is characterized in that the trip coil detection circuit 5 is a resistor R3 with one end connected to the control circuit 1, one end of the trip coil 2 is connected to the power supply circuit 8, and the other end of the trip coil 2 is connected to the other end of the resistor R3.

[0009] As described above, a leakage protection circuit for automatic monitoring of a leakage protection device is characterized in that the thyristor SCR detection circuit 6 includes a diode D1 and a diode D2, the positive terminal of the diode D2 is connected to the control circuit 1, the negative terminal of the diode D2 is respectively connected to the positive terminal of the thyristor SCR and the negative terminal of the diode D1, the positive terminal of the diode D1 is connected to the trip coil 2, the control terminal of the thyristor SCR is connected to the control circuit 1 through a resistor R4, the negative terminal of the thyristor SCR is grounded, and a capacitor C2 is connected in parallel between the control terminal and the negative terminal of the thyristor SCR.

[0010] As described above, a leakage protection circuit that can be automatically monitored for a leakage protection device is characterized in that the automatic simulation leakage circuit 4 includes a transistor Q1, the base of the transistor Q1 is connected to the control circuit 1 through a resistor R8, the collector of the transistor Q1 is connected to the negative end of the diode D4 through a resistor R9, the positive end of the diode D4 is connected to the live wire input end of the leakage protection device, and the emitter lead of the transistor Q1 is connected to the zero-sequence mutual inductor 3 after being wound around the zero-sequence mutual inductor and connected to the zero-line input end of the leakage protection device.

[0011] As described above, a leakage protection circuit that can be automatically monitored for use in a leakage protection device is characterized in that the fault warning light circuit 7 includes a light emitting diode LED, the positive terminal of the light emitting diode LED is connected to the control circuit 1 through a resistor R5, and the negative terminal of the light emitting diode LED is grounded.

[0012] As described above, a leakage protection circuit that can be automatically monitored for a leakage protection device is characterized in that the zero-sequence transformer 3 is connected to a test circuit 9, and the test circuit 9 includes a test button S1. One end of the test button S1 is connected to the live wire output end of the leakage protection device after the lead wire is wound around the zero-sequence transformer 3. The test button S1 is connected to the neutral wire output end of the leakage protection device through a resistor R1.

[0013] As described above, a leakage protection circuit that can be automatically monitored for use in a leakage protection device is characterized in that the zero-sequence mutual inductor 3 is set on the neutral and live wires of the power supply circuit 8, a reset switch K1 is connected to the neutral and live wires of the power supply circuit 8, a varistor MOV is connected between the input ends of the neutral and live wires of the power supply circuit 8, the input ends of the neutral and live wires of the power supply circuit 8 respectively supply power to the control circuit 1, the tripping coil 2, and the automatic simulation leakage circuit 4, and the output ends of the neutral and live wires of the power supply circuit 8 supply power to the test circuit 9.

[0014] As described above, a leakage protection circuit that can be automatically monitored for use in a leakage protection device is characterized in that the live wire input end of the power supply circuit 8 is connected to the positive end of a diode D3, and the negative end of the diode D3 is connected to the control circuit 1 through a resistor R2 for power supply.

[0015] The beneficial effects of the present invention are:

[0016] The present invention automatically detects the leakage protection function of the leakage protection device immediately after power is turned on. If it is detected that the leakage protection function fails, the power supply circuit is immediately disconnected or an alarm is issued to remind the user to replace it. The leakage protection device with long-term power supply can automatically and regularly monitor whether the leakage protection function of the leakage protection device is normal. When the protection function fails, the power supply is disconnected or an alarm is issued to remind the user to replace it, thereby greatly improving the safety of use. [Drawings]

[0017] Figure 1 It is the principle diagram of the present invention;

[0018] Figure 2 It is a schematic diagram of the circuit structure of the present invention;

[0019] Figure 3 A schematic diagram of a leakage protection plug using the present invention;

[0020] Figure 4 An exploded view of the leakage protection plug of the present invention;

[0021] Figure 5 A schematic diagram of a leakage protection socket using the present invention;

[0022] Figure 6 This is one of the exploded views of the leakage protection socket to which the present invention is applied;

[0023] Figure 7 The second exploded view of the leakage protection socket using the present invention. [Specific implementation method]

[0024] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings:

[0025] like Figure 1-2 As shown, a leakage protection circuit for automatic monitoring of a leakage protection device includes a control circuit 1 and a tripping coil 2 for tripping and powering off the leakage protection device, wherein the control circuit 1 is connected to a zero-sequence transformer 3 for detecting zero-live leakage of the leakage protection device and detecting simulated leakage, an automatic simulated leakage circuit 4 for sending a simulated leakage signal to the zero-sequence transformer 3 during the negative half cycle of the power supply voltage phase, a tripping coil detection circuit 5 for detecting whether the voltage of the tripping coil 2 is normal, a thyristor SCR for controlling the tripping coil 2 to trip and power off when there is leakage of the zero-live wire, a thyristor SCR detection circuit 6 for detecting whether the thyristor SCR is working normally when the simulated leakage signal is detected, and a fault warning light circuit 7 for alarming when the tripping coil 2 or the thyristor SCR cannot work normally.

[0026] Among them, Figure 2As shown, the trip coil detection circuit 5 is a resistor R3 having one end connected to the control circuit 1 , one end of the trip coil 2 is connected to the power circuit 8 , and the other end of the trip coil 2 is connected to the other end of the resistor R3 .

[0027] The thyristor SCR detection circuit 6 includes a diode D1 and a diode D2, wherein the positive terminal of the diode D2 is connected to the control circuit 1, the negative terminal of the diode D2 is respectively connected to the positive terminal of the thyristor SCR and the negative terminal of the diode D1, the positive terminal of the diode D1 is connected to the tripping coil 2, the control terminal of the thyristor SCR is connected to the control circuit 1 through a resistor R4, the negative terminal of the thyristor SCR is grounded, and a capacitor C2 is connected in parallel between the control terminal and the negative terminal of the thyristor SCR.

[0028] The automatic simulated leakage circuit 4 includes a transistor Q1, the base of the transistor Q1 is connected to the control circuit 1 through a resistor R8, the collector of the transistor Q1 is connected to the negative end of the diode D4 through a resistor R9, the positive end of the diode D4 is connected to the live wire input end of the leakage protection device, and the emitter lead of the transistor Q1 is connected to the zero-sequence mutual inductor 3 after being wound around the zero-sequence mutual inductor and then connected to the zero-line input end of the leakage protection device.

[0029] The fault warning light circuit 7 includes a light emitting diode LED, the positive terminal of the light emitting diode LED is connected to the control circuit 1 through a resistor R5, and the negative terminal of the light emitting diode LED is grounded.

[0030] The control circuit 2 has a leakage detection protection function and an automatic monitoring leakage protection function, which can realize a normal leakage protection function and regularly monitor whether the leakage protection function is normal.

[0031] The normal leakage protection function of the present invention is realized as follows: the power current passes through the reset switch K1 contact in the power circuit 8 and then passes through the ZCT zero-sequence current transformer 3 to supply power to the electrical appliance; when a leakage fault occurs at the electrical appliance end, the ZCT zero-sequence current transformer 3 detects the residual current signal and transmits it to the control chip U1 of the control circuit 1 for comparison. When the residual current value exceeds the preset value of the control chip U1, the control chip U1 outputs a high level to the thyristor SCR through the control end, so that the thyristor SCR is turned on. At this time, the trip coil 2 is energized, and the current flowing through the trip coil 2 generates magnetic force to disconnect the reset switch K1.

[0032] The automatic monitoring of the leakage protection function of the present invention is realized as follows: after power is turned on, the voltage of the trip coil 2 is detected by the resistor R3 of the trip coil detection circuit 5 to determine whether the trip coil is disconnected. When the voltage value is normal, the control chip U1 of the control circuit 1 does not need to respond. When an abnormal voltage value is detected, the control chip U1 outputs a pulse signal to the fault warning light circuit 7, and the fault indication light emitting diode LED flashes through the diode R5, reminding the user to replace the leakage protection device.

[0033] Within 5 seconds after power-on, in the negative half cycle of the power supply voltage phase, the control chip U1 of the control circuit 1 outputs a set of pulse signals to the automatic simulation leakage circuit 4, and controls the base of the transistor Q1 through the resistor R8, so that the diode D4, the resistor R9, and the transistor Q1 generate a set of leakage signals in the ZCT zero-sequence current transformer 3, and the set of leakage signals is transmitted to the control chip U1 through the ZCT zero-sequence current transformer 3. After comparison and judgment, the control chip U1 outputs a high level to the thyristor SCR through the output thyristor SCR control terminal, so that the thyristor SCR is turned on. At this time, because it is in the negative half cycle of the power supply phase, the diode D1 is in the disconnected state, so no current flows in the trip coil 2, so that the reset switch K1 will not be disconnected. At the same time, the SCR test pin of the control chip U1 outputs a high level. Since the thyristor SCR is in the on state, the high level output by the SCR test pin is reduced to less than 2V after passing through the diode D2 and the thyristor SCR. After the SCR test pin of the control chip U1 detects this voltage falling edge, it can be determined that the leakage protection function of the product is normal. If this voltage falling edge cannot be detected, there must be a fault in the entire leakage detection circuit. Then the control chip U1 outputs a pulse signal, and the fault indication light emitting diode LED flashes through the diode R5, reminding the user to replace the leakage protection device.

[0034] like Figure 2 As shown, the zero-sequence transformer 3 is connected to a test circuit 9, and the test circuit 9 includes a test button S1. One end of the test button S1 is connected to the live wire output end of the leakage protection device after the lead wire is wound around the zero-sequence transformer 3. The test button S1 is connected to the neutral wire output end of the leakage protection device through a resistor R1.

[0035] Manually verify the realization of the leakage protection function: manually press the test switch S1 in the test circuit 9, and generate an analog leakage signal in the ZCT zero-sequence current transformer 3 through the resistor R1. The ZCT zero-sequence current transformer 3 detects the residual current signal and transmits it to the control chip U1 of the control circuit 1 for comparison. When the residual current value exceeds the preset value of the control chip U1, the control chip U1 outputs a high level to the thyristor SCR through the control end, so that the thyristor SCR is turned on. At this time, the tripping coil 2 is energized, and the current flowing through the tripping coil 2 generates magnetic force to disconnect the reset switch K1. At this time, the leakage protection function is normal, otherwise the leakage protection function is abnormal, and the leakage protection device needs to be replaced.

[0036] like Figure 2As shown, the zero-sequence mutual inductor 3 is set on the neutral and live wires of the power supply circuit 8, the reset switch K1 is connected to the neutral and live wires of the power supply circuit 8, a varistor MOV is connected between the zero and live wire input ends of the power supply circuit 8, the zero and live wire input ends of the power supply circuit 8 respectively supply power to the control circuit 1, the trip coil 2, and the automatic simulated leakage circuit 4, and the zero and live wire output ends of the power supply circuit 8 supply power to the test circuit 9, wherein the live wire input end of the power supply circuit 8 is connected to the positive end of the diode D3, and the negative end of the diode D3 is connected to the control circuit 1 through the resistor R2 for power supply.

[0037] like Figure 3-4 As shown, the circuit of the present invention can be applied to a leakage protection plug 101. The lower shell of the leakage protection plug 101 is provided with a live wire pin, a neutral wire pin, and a ground wire pin. The upper shell of the leakage protection plug 101 is provided with a reset switch K1 and a test button S1. The leakage protection plug 101 is provided with a circuit board 102, a tripping coil 2, and an elastic buckle device 103. The control circuit 1, the automatic simulation leakage circuit 4, the tripping coil detection circuit 5, the thyristor SCR, the thyristor SCR detection circuit 6, the test circuit 9, and the power supply circuit 8 are respectively arranged on the circuit board 102, and The live wire pin and the neutral wire pin are connected to the circuit board 102 as the neutral and live wire input terminals respectively. After the switch K1 is pressed, the elastic snap device 103 is in a snap-connected state to connect the static contact of the neutral and live wires with the moving contact, thereby connecting the neutral and live wire input terminals with the neutral and live wire output terminals. On the other hand, when leakage is detected, the control circuit 1 controls the tripping coil 2 to work through the thyristor SCR, so that the tripping coil 2 attracts the armature to disconnect the reset switch K1, and releases the snap-connected state of the elastic snap device 103, thereby disconnecting the static contact of the neutral and live wires from the moving contact.

[0038] like Figure 5-7As shown, the circuit of the present invention can be applied to a leakage protection socket 201, the electrical protection socket 201 is provided with a two-connection socket, a three-connection socket, a reset switch K1, and a test button S1, the electrical protection socket 201 is provided with a neutral-live input interface 203, a circuit board 102, a tripping coil 2, an elastic snap device 103, a two-connection socket connecting piece 202 at the neutral-live output end, and a three-connection socket connecting piece 203 at the neutral-live output end, wherein the control circuit 1, the automatic simulation leakage circuit 4, the tripping coil detection circuit 5, the thyristor SCR, and the thyristor SCR detection detection circuit 5 are Circuit 6, test circuit 9, and power supply circuit 8 are respectively arranged on the circuit board 102. After the switch K1 is pressed, the elastic snap device 103 is in a snap-connected state to connect the static contact of the neutral and live wires with the moving contact, thereby connecting the neutral and live wire input ends with the neutral and live wire output ends. On the other hand, when leakage is detected, the control circuit 1 controls the tripping coil 2 to work through the thyristor SCR, so that the tripping coil 2 attracts the armature to disconnect the reset switch K1, and releases the snap-connected state of the elastic snap device 103, thereby disconnecting the static contact of the neutral and live wires from the moving contact.

Claims

1. A leakage protection circuit for automatic monitoring of a leakage protection device, characterized in that: The invention comprises a control circuit (1) and a tripping coil (2) for causing a leakage protection device to trip and cut off power. The control circuit (1) is connected to a zero-sequence transformer (3) for detecting leakage of zero and live wires of the leakage protection device and detecting simulated leakage, an automatic simulated leakage circuit (4) for sending a simulated leakage signal to the zero-sequence transformer (3) during the negative half cycle of the power supply voltage phase, a tripping coil detection circuit (5) for detecting whether the voltage of the tripping coil (2) is normal, a thyristor (SCR) for controlling the tripping coil (2) to trip and cut off power when leakage of zero and live wires occurs, a thyristor (SCR) detection circuit (6) for detecting whether the thyristor (SCR) is working normally when the simulated leakage signal is detected, and a fault warning lamp circuit (7) for alarming when the tripping coil (2) or the thyristor (SCR) fails to work normally. The trip coil detection circuit (5) is a resistor R3 having one end connected to the control circuit (1), one end of the trip coil (2) is connected to the power supply circuit (8), and the other end of the trip coil (2) is connected to the other end of the resistor R3; The thyristor SCR detection circuit (6) comprises a diode D1 and a diode D2, wherein the positive terminal of the diode D2 is connected to the control circuit (1), the negative terminal of the diode D2 is respectively connected to the positive terminal of the thyristor SCR and the negative terminal of the diode D1, the positive terminal of the diode D1 is connected to the tripping coil (2), the control terminal of the thyristor SCR is connected to the control circuit (1) via a resistor R4, the negative terminal of the thyristor SCR is grounded, and a capacitor C2 is connected in parallel between the control terminal and the negative terminal of the thyristor SCR; The automatic simulated leakage circuit (4) comprises a transistor Q1, the base of the transistor Q1 is connected to the control circuit (1) via a resistor R8, the collector of the transistor Q1 is connected to the negative terminal of a diode D4 via a resistor R9, the positive terminal of the diode D4 is connected to the live wire input terminal of a leakage protection device, and the emitter lead of the transistor Q1 is connected to the zero-line input terminal of the leakage protection device after being wound around a zero-sequence mutual inductor (3); The fault warning light circuit (7) comprises a light emitting diode (LED), wherein the positive terminal of the light emitting diode (LED) is connected to the control circuit (1) via a resistor R5, and the negative terminal of the light emitting diode (LED) is grounded; The zero-sequence transformer (3) is connected to a test circuit (9), and the test circuit (9) includes a test button S1, a lead wire at one end of the test button S1 is wound around the zero-sequence transformer (3) and connected to the live wire output end of the leakage protection device, and the test button S1 is connected to the neutral wire output end of the leakage protection device via a resistor R1; The zero-sequence mutual inductor (3) is sleeved on the neutral and live wires of the power supply circuit (8). A reset switch K1 is connected to the neutral and live wires of the power supply circuit (8). A varistor MOV is connected between the input ends of the neutral and live wires of the power supply circuit (8). The input ends of the neutral and live wires of the power supply circuit (8) respectively supply power to the control circuit (1), the tripping coil (2), and the automatic simulated leakage circuit (4). The output ends of the neutral and live wires of the power supply circuit (8) supply power to the test circuit (9).

2. The leakage protection circuit for automatic monitoring of a leakage protection device according to claim 1, characterized in that: The live wire input end of the power supply circuit (8) is connected to the positive end of a diode D3, and the negative end of the diode D3 is connected to the control circuit (1) via a resistor R2 for power supply.

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