A safety protection circuit for power distribution cabinet

Abstract

The invention discloses a safety protection circuit of a power distribution cabinet, and relates to the field of safety protection. The safety protection circuit of the power distribution cabinet comprises: a power distribution module, which is used to supply the voltage on a main line to different areas through a branch line, and the main line comprises three switches, namely a first switch, a second switch, and a third switch; a cabinet door opening feedback module, which is used to control the second switch on the main line to be disconnected when the door of the power distribution cabinet is opened; a distance sensing control module is set, and the third switch on the main line is controlled to be disconnected when the maintenance personnel approaches the main line; double protection is set to reduce the possibility of electric shock when the maintenance personnel do not fully wear insulating equipment, and when the maintenance personnel need to power on, they must stay away from the main line and close the door of the power distribution cabinet to power on, so as to avoid powering on at close range, which is safer.

Description

Technical Field

[0001] The invention relates to the field of safety protection, in particular to a safety protection circuit of a power distribution cabinet. Background Art

[0002] When the power distribution cabinet triggers a protective power outage, it is often necessary to inspect the cabinet and restore power after the inspection is completed. If conditions permit, other components in the cabinet will also be checked for faults.

[0003] When strictly following the maintenance requirements, maintenance personnel will wear insulating equipment (insulating gloves, insulating boots, insulating long-sleeved work clothes, etc.) to reduce the incidence of electrical accidents. However, in the actual maintenance process, there is a situation where the insulation equipment is not fully worn (for example, only insulating gloves are worn) when the distribution cabinet is repaired, which leads to frequent accidents and needs to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide a safety protection circuit for a power distribution cabinet to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A safety protection circuit of a power distribution cabinet, comprising:

[0007] A power distribution module is used to supply the voltage on the main line to different areas through branch lines. The main line includes three switches, namely a first switch, a second switch, and a third switch;

[0008] The cabinet door opening feedback module is used to supply power to the voice prompt control module and the distance sensing control module when the cabinet door of the power distribution cabinet is opened;

[0009] A voice prompt control module is used to give voice prompts to maintenance personnel to wear insulating equipment after voltage is input, and to control the second switch to disconnect;

[0010] A distance sensing control module is used to detect the distance between the maintenance personnel and the main line after the voltage is input, and control the third switch to be disconnected when the distance between the maintenance personnel and the main line is lower than a threshold value;

[0011] A working status indication module, used to indicate the working status of the voice prompt control module and the distance sensing control module through a light-emitting tube, and to indicate whether the second switch and the third switch are disconnected or not;

[0012] The output end of the cabinet door opening feedback module is connected to the input end of the voice prompt control module and the input end of the distance sensing control module. The first output end of the voice prompt control module is connected to the first input end of the working status indication module. The first output end of the distance sensing control module is connected to the second input end of the working status indication module. The second output end of the voice prompt control module is connected to the first input end of the power distribution module. The second output end of the distance sensing control module is connected to the second input end of the power distribution module.

[0013] As a further solution of the present invention: the power distribution module includes a main line, a first switch, a second switch, a third switch, and multiple branch lines. The main line supplies power to the multiple branch lines through the first switch, the second switch, and the third switch in turn, and a protection unit is arranged on each branch line.

[0014] As a further scheme of the present invention: the protection unit includes a current transformer, a first diode, a first capacitor, a seventh resistor, a first amplifier, a fifth switch, a first resistor, a thyristor, a fourth relay, and a second diode. The current transformer samples the current of the branch line. One end of the current transformer is grounded, and the other end of the current transformer is connected to the positive electrode of the first diode. The negative electrode of the first diode is connected to one end of the first capacitor, one end of the seventh resistor, and the in-phase end of the first amplifier. The other end of the first capacitor is grounded, and the other end of the seventh resistor is grounded. The inverting end of the first amplifier is connected to the first reference voltage. The output end of the first amplifier is connected to the control electrode of the thyristor, the positive electrode of the thyristor is connected to one end of the first resistor, and the other end of the first resistor is connected to one end of the fifth switch. The other end of the fifth switch is connected to the power supply voltage, the negative electrode of the thyristor is connected to one end of the fourth relay and the negative electrode of the second diode. The other end of the fourth relay is grounded, and the positive electrode of the second diode is grounded. When the fourth relay is working, the fourth switch on the branch line where the fourth relay is located is controlled to be disconnected.

[0015] As a further solution of the present invention: the cabinet door opening feedback module includes a second resistor and a sixth switch, one end of the second resistor is connected to the power supply voltage, the other end of the second resistor is connected to one end of the sixth switch, and the other end of the sixth switch is connected to the input end of the voice prompt control module and the input end of the distance sensing control module. When the cabinet door of the distribution cabinet is opened, the sixth switch is closed, and when the cabinet door of the distribution cabinet is closed, the sixth switch pops open.

[0016] As a further solution of the present invention: the voice prompt control module includes a voice chip, a second capacitor, a third capacitor, a third resistor, a fourth resistor, a first transistor, a third diode, a fourth capacitor, a second relay, and a fifth diode. The power supply end of the voice chip is connected to one end of the third resistor, one end of the fourth resistor, and the output end of the cabinet door opening feedback module. The ground end of the voice chip is grounded. The output end of the voice chip is connected to one end of the second capacitor, the other end of the second capacitor is connected to the other end of the third resistor, one end of the third capacitor, and the base of the first transistor. The other end of the third capacitor is grounded, the collector of the first transistor is connected to the other end of the fourth resistor, the emitter of the first transistor is connected to the positive electrode of the third diode, the negative electrode of the third diode is connected to one end of the fourth capacitor, one end of the second relay, the negative electrode of the fifth diode, and the first input end of the working status indication module, the other end of the second relay is grounded, the positive electrode of the fifth diode is grounded, and the other end of the fourth capacitor is grounded.

[0017] As a further solution of the present invention: the distance sensing control module includes a human proximity sensor, a fourth amplifier, a fifth resistor, a second transistor, a third relay, and a fourth diode. The power supply end of the human proximity sensor is connected to the output end of the cabinet door opening feedback module, the ground end of the human proximity sensor is grounded, the output end of the human proximity sensor is connected to the in-phase end of the fourth amplifier, the inverting end of the fourth amplifier is connected to the second reference voltage, the output end of the fourth amplifier is connected to the base of the second transistor, the collector of the second transistor is connected to the power supply voltage through the fifth resistor, the emitter of the second transistor is connected to one end of the third relay, the cathode of the fourth diode, and the second input end of the working status indication module, the other end of the third relay is grounded, and the anode of the fourth diode is grounded.

[0018] As a further solution of the present invention: the working status indication module includes a sixth diode, a seventh diode, an eighth diode, a fifth AND gate, and a sixth resistor. The positive electrode of the seventh diode is connected to the first output end of the voice prompt control module, the positive electrode of the eighth diode is connected to the first output end of the distance sensing control module, the negative electrode of the seventh diode is connected to the first input end of the fifth AND gate, the negative electrode of the eighth diode is connected to the second input end of the fifth AND gate, the output end of the fifth AND gate is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the positive electrode of the sixth diode, the negative electrode of the sixth diode is grounded, and the sixth diode, the seventh diode, and the eighth diode are light-emitting diodes.

[0019] Compared with the prior art, the beneficial effects of the present invention are: the present invention sets a voice prompt control module, and when the maintenance personnel opens the door of the distribution cabinet, the second switch on the main line is controlled to be disconnected; a distance sensing control module is set, and when the maintenance personnel approaches the main line, the third switch on the main line is controlled to be disconnected; double protection is set to reduce the possibility of electric shock when the maintenance personnel do not fully wear insulating equipment, and when the maintenance personnel need to power on, they must stay away from the main line and close the door of the distribution cabinet to power on, avoiding powering on at close range, which is safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The utility model is a schematic diagram of a safety protection circuit of a power distribution cabinet.

[0021] Figure 2 This is the circuit diagram of the power distribution module.

[0022] Figure 3 This is the circuit diagram of the protection unit.

[0023] Figure 4 The circuit diagram of the cabinet door opening feedback module, voice prompt control module, distance sensing control module and working status indication module. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] See also Figure 1 , a safety protection circuit of a power distribution cabinet, comprising:

[0026] The power distribution module 1 is used to supply the voltage on the main line to different areas through the branch line. The main line includes three switches, namely the first switch S1, the second switch S2, and the third switch S3 (i.e., the main switch, the cabinet door switch, and the distance switch respectively);

[0027] The cabinet door opening feedback module 2 is used to supply power to the voice prompt control module 3 and the distance sensing control module 4 when the cabinet door of the power distribution cabinet is opened;

[0028] The voice prompt control module 3 is used to give a voice prompt to the maintenance personnel to wear insulating equipment after the voltage is input, and to control the second switch S2 to be disconnected;

[0029] The distance sensing control module 4 is used to detect the distance between the maintenance personnel and the main line after the voltage is input, and control the third switch S3 to be disconnected when the distance between the maintenance personnel and the main line is lower than a threshold value;

[0030] The working state indicating module 5 is used to indicate the working state of the voice prompt control module 3 and the distance sensing control module 4 through the light emitting tube, and to indicate whether the second switch S2 and the third switch S3 are disconnected or not;

[0031] The output end of the cabinet door opening feedback module 2 is connected to the input end of the voice prompt control module 3 and the input end of the distance sensing control module 4, the first output end of the voice prompt control module 3 is connected to the first input end of the working status indication module 5, the first output end of the distance sensing control module 4 is connected to the second input end of the working status indication module 5, the second output end of the voice prompt control module 3 is connected to the first input end of the power distribution module 1, and the second output end of the distance sensing control module 4 is connected to the second input end of the power distribution module 1.

[0032] In this example: See Figure 2 The power distribution module 1 includes a main line, a first switch S1, a second switch S2, a third switch S3, and multiple branch lines. The main line supplies power to multiple branch lines through the first switch S1, the second switch S2, and the third switch S3 in turn, and a protection unit X is provided on each branch line.

[0033] The voltage on the main line supplies power to the branch lines through the first switch S1, the second switch S2, and the third switch S3, and the multiple branch lines are connected in parallel.

[0034] The first switch S1 is a main switch, which is controlled by a relay. The relay is not shown here. Control by relay is a common technology and will not be described in detail here.

[0035] Figure 2 There are three branch lines, and there is no limit on the number of branch lines in actual use.

[0036] In another embodiment: the first switch S1 can be omitted. The first switch S1 serves as a main switch and is usually closed manually by maintenance personnel during maintenance. The second switch S2 and the third switch S3 (cabinet door switch, distance switch) here are automatically closed or opened. Considering the situation of control failure, it is safer to set the first switch S1.

[0037] In this example: See Figure 3The protection unit X includes a current transformer Y, a first diode D1, a first capacitor C1, a seventh resistor R7, a first amplifier U1, a fifth switch S5, a first resistor R1, a thyristor Z1, a fourth relay J1, and a second diode D2. The current transformer Y samples the current of the branch line. One end of the current transformer Y is grounded, and the other end of the current transformer Y is connected to the positive electrode of the first diode D1. The negative electrode of the first diode D1 is connected to one end of the first capacitor C1, one end of the seventh resistor R7, and the in-phase end of the first amplifier U1. The other end of the first capacitor C1 is grounded, and the other end of the seventh resistor R7 is grounded. The inverting end of the first amplifier U1 is connected to the first reference voltage VREF1, the output end of the first amplifier U1 is connected to the control electrode of the thyristor Z1, the positive electrode of the thyristor Z1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the fifth switch S5, the other end of the fifth switch S5 is connected to the power supply voltage VCC, the negative electrode of the thyristor Z1 is connected to one end of the fourth relay J1 and the negative electrode of the second diode D2, the other end of the fourth relay J1 is grounded, the positive electrode of the second diode D2 is grounded, and when the fourth relay J1 is working, the fourth switch S4 on the branch line where the fourth relay J1 is located is controlled to be disconnected.

[0038] The current transformer Y samples the current flowing through the live wire on the corresponding branch line, and after being processed by the first diode D1 and the first capacitor C1, it becomes a stable direct current, and forms a voltage signal on the seventh resistor R7, which is output to the in-phase end of the first amplifier U1. When the current is large due to excessive load or power supply failure on the branch line, the voltage at the in-phase end of the first amplifier U1 is higher than the first reference voltage VREF1 at the inverting end, and the first amplifier U1 outputs a high level, triggering the thyristor Z1 to turn on, and the fourth relay J1 is powered on, controlling the fourth switch S4 on the corresponding branch line to disconnect, so as to avoid large current damaging the device. After maintenance, it is only necessary to disconnect the normally closed fifth switch S5 and then close it again. At this time, the thyristor Z1 is cut off, the fourth relay J1 stops working, and the fourth switch S4 resumes the closed state.

[0039] In another embodiment, the protection unit X can be replaced by a fuse, which has the advantage of simple structure and the disadvantage of requiring a new fuse to be replaced after the fuse is activated and the protection is disconnected, which is relatively cumbersome.

[0040] In this example: See Figure 4 The cabinet door opening feedback module 2 includes a second resistor R2 and a sixth switch S6. One end of the second resistor R2 is connected to the power supply voltage VCC, the other end of the second resistor R2 is connected to one end of the sixth switch S6, and the other end of the sixth switch S6 is connected to the input end of the voice prompt control module 3 and the input end of the distance sensing control module 4. When the cabinet door of the distribution cabinet is opened, the sixth switch S6 is closed, and when the cabinet door of the distribution cabinet is closed, the sixth switch S6 pops open.

[0041] A magnet is provided at the door of the distribution cabinet. When the door of the distribution cabinet is closed, the magnet attracts the sixth switch S6, so that the sixth switch S6 is normally open; when the door of the distribution cabinet is opened, the sixth switch S6 is away from the magnet and becomes a closed state; therefore, when the door of the distribution cabinet is opened, the power supply voltage VCC is supplied to the voice prompt control module 3 and the distance sensing control module 4 through the second resistor R2 and the sixth switch S6.

[0042] In another embodiment, the power supply voltage VCC may be supplied by a battery, or may be obtained by stepping down, rectifying, filtering and stabilizing the voltage on the main line.

[0043] In this example: See Figure 4 The voice prompt control module 3 includes a voice chip U2, a second capacitor C2, a third capacitor C3, a third resistor R3, a fourth resistor R4, a first transistor V1, a third diode D3, a fourth capacitor C4, a second relay J2, and a fifth diode D5. The power supply end of the voice chip U2 is connected to one end of the third resistor R3, one end of the fourth resistor R4, and the output end of the cabinet door opening feedback module 2. The ground end of the voice chip U2 is grounded. The output end of the voice chip U2 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is connected to the third resistor R3. The other end, one end of the third capacitor C3, and the base of the first transistor V1, the other end of the third capacitor C3 is grounded, the collector of the first transistor V1 is connected to the other end of the fourth resistor R4, the emitter of the first transistor V1 is connected to the anode of the third diode D3, the cathode of the third diode D3 is connected to one end of the fourth capacitor C4, one end of the second relay J2, the cathode of the fifth diode D5, and the first input end of the working status indication module 5, the other end of the second relay J2 is grounded, the anode of the fifth diode D5 is grounded, and the other end of the fourth capacitor C4 is grounded.

[0044] After the voltage is input, the voice chip U2 is powered on and works. The voice chip U2 can be WTN6 series, GYN6 series, etc. The voice chip U2 gives a voice prompt "Please wear insulating equipment". At the same time, the voice chip U2 outputs a signal, which is amplified by the first transistor V1, rectified by the third diode D3, and filtered by the fourth capacitor C4. The second relay J2 is triggered to be powered on and works, and the working status indication module 5 is powered at the same time. After the second relay J2 is powered on, the second switch S2 is controlled to pop open. Therefore, when the maintenance personnel open the door of the distribution cabinet, the voice chip U2 prompts to wear insulating equipment and controls the second switch S2 to be disconnected to ensure the safety of the maintenance personnel.

[0045] In another embodiment: the voice chip U2 illustrated as an example is a one-time programmable voice chip, and may also be a rewritable voice chip.

[0046] In this example: See Figure 4The distance sensing control module 4 includes a human proximity sensor U3, a fourth amplifier U4, a fifth resistor R5, a second triode V2, a third relay J3, and a fourth diode D4. The power supply end of the human proximity sensor U3 is connected to the output end of the cabinet door opening feedback module 2, the ground end of the human proximity sensor U3 is grounded, the output end of the human proximity sensor U3 is connected to the in-phase end of the fourth amplifier U4, the inverting end of the fourth amplifier U4 is connected to the second reference voltage VREF2, the output end of the fourth amplifier U4 is connected to the base of the second triode V2, the collector of the second triode V2 is connected to the power supply voltage VCC through the fifth resistor R5, the emitter of the second triode V2 is connected to one end of the third relay J3, the cathode of the fourth diode D4, and the second input end of the working status indication module 5, the other end of the third relay J3 is grounded, and the anode of the fourth diode D4 is grounded.

[0047] After the door of the power distribution cabinet is opened, the human proximity sensor U3 is powered on and starts working. When the human body approaches the main line (the human proximity sensor U3 is set at the main line) and is ready for maintenance, when the human body is close enough to the human proximity sensor U3, the output voltage of the human proximity sensor U3 is relatively large, which is higher than the second reference voltage VREF2, and the fourth amplifier U4 outputs a high level, the second transistor V2 is turned on, and the third relay J3 is powered on and starts working, controlling the third switch S3 to be disconnected. When the distance to the maintenance area is close, another protection measure is added to avoid electric shock. The human proximity sensor U3 can be the YTMW8631 dedicated to ATM.

[0048] In another embodiment: the human proximity sensor U3 can be replaced by an infrared sensor.

[0049] In this example: See Figure 4 The working status indication module 5 includes a sixth diode D6, a seventh diode D7, an eighth diode D8, a fifth AND gate U5, and a sixth resistor R6. The anode of the seventh diode D7 is connected to the first output end of the voice prompt control module 3, the anode of the eighth diode D8 is connected to the first output end of the distance sensing control module 4, the cathode of the seventh diode D7 is connected to the first input end of the fifth AND gate U5, the cathode of the eighth diode D8 is connected to the second input end of the fifth AND gate U5, the output end of the fifth AND gate U5 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is connected to the anode of the sixth diode D6, the cathode of the sixth diode D6 is grounded, and the sixth diode D6, the seventh diode D7, and the eighth diode D8 are light emitting diodes.

[0050] When maintenance is needed, the maintenance personnel put on the insulating equipment and open the door of the power distribution cabinet. At this time, the sixth switch S6 is closed, the voice chip U2 is powered on, the second relay J2 controls the second switch S2 to pop open, the positive pole of the seventh diode D7 is powered on to indicate light, and provides a high level for the first input end of the fifth AND gate U5. As the maintenance personnel approach the main line, the output voltage of the human proximity sensor U3 increases, and finally the fourth amplifier U4 outputs a high level, the second triode V2 is turned on, the third relay J3 is powered on to work, the third switch S3 pops open, the eighth diode D8 indicates light, and provides a high level for the second input end of the fifth AND gate U5. The fifth AND gate U5 outputs a high level, and the sixth diode D6 indicates light. Therefore, when working normally, the seventh diode D7 and the eighth diode D8 emit light in turn. When the eighth diode D8 emits light, the sixth diode D6 also emits light. When there is a diode that does not emit light, it can be judged that the voice prompt control module 3 and the distance sensing control module 4 have a fault, which is convenient for maintenance personnel to predict danger in time.

[0051] In another embodiment: the seventh diode D7 (eighth diode D8) can be composed of two light-emitting diodes connected in parallel, so that when one diode fails, the other diode still emits light for indication, thereby avoiding misjudgment by maintenance personnel due to no light emission caused by a diode failure.

[0052] The working principle of the present invention is: the power distribution module 1 is used to supply the voltage on the main line to different areas through the branch line. The main line includes three switches, namely the first switch S1, the second switch S2, and the third switch S3; the cabinet door opening feedback module 2 is used to supply power to the voice prompt control module 3 and the distance sensing control module 4 when the cabinet door of the distribution cabinet is opened; the voice prompt control module 3 is used to give voice prompts to the maintenance personnel to wear insulating equipment after the voltage is input, and control the second switch S2 to be disconnected; the distance sensing control module 4 is used to detect the distance between the maintenance personnel and the main line after the voltage is input, and control the third switch S3 to be disconnected when the distance between the maintenance personnel and the main line is lower than the threshold; the working status indication module 5 is used to indicate the working status of the voice prompt control module 3 and the distance sensing control module 4 through the light-emitting tube, and indicate whether the second switch S2 and the third switch S3 are disconnected or not.

[0053] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered as exemplary and non-restrictive in all respects.

[0054] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A safety protection circuit for a power distribution cabinet, characterized in that: The safety protection circuit of the power distribution cabinet includes: A power distribution module is used to supply the voltage on the main line to different areas through branch lines. The main line includes three switches, namely a first switch, a second switch, and a third switch; The cabinet door opening feedback module is used to supply power to the voice prompt control module and the distance sensing control module when the cabinet door of the power distribution cabinet is opened; A voice prompt control module is used to give voice prompts to maintenance personnel to wear insulating equipment after voltage is input, and to control the second switch to disconnect; A distance sensing control module is used to detect the distance between the maintenance personnel and the main line after the voltage is input, and control the third switch to be disconnected when the distance between the maintenance personnel and the main line is lower than a threshold value; A working status indication module, used to indicate the working status of the voice prompt control module and the distance sensing control module through a light-emitting tube, and to indicate whether the second switch and the third switch are disconnected or not; The output end of the cabinet door opening feedback module is connected to the input end of the voice prompt control module and the input end of the distance sensing control module, the first output end of the voice prompt control module is connected to the first input end of the working state indication module, the first output end of the distance sensing control module is connected to the second input end of the working state indication module, the second output end of the voice prompt control module is connected to the first input end of the power distribution module, and the second output end of the distance sensing control module is connected to the second input end of the power distribution module; The cabinet door opening feedback module includes a second resistor and a sixth switch, one end of the second resistor is connected to the power supply voltage, the other end of the second resistor is connected to one end of the sixth switch, and the other end of the sixth switch is connected to the input end of the voice prompt control module and the input end of the distance sensing control module. When the cabinet door of the power distribution cabinet is opened, the sixth switch is closed, and when the cabinet door of the power distribution cabinet is closed, the sixth switch pops open; The voice prompt control module includes a voice chip, a second capacitor, a third capacitor, a third resistor, a fourth resistor, a first triode, a third diode, a fourth capacitor, a second relay, and a fifth diode. The power supply end of the voice chip is connected to one end of the third resistor, one end of the fourth resistor, and the output end of the cabinet door opening feedback module. The ground end of the voice chip is grounded. The output end of the voice chip is connected to one end of the second capacitor, the other end of the second capacitor is connected to the other end of the third resistor, one end of the third capacitor, and the base of the first triode. The other end of the third capacitor is grounded, the collector of the first triode is connected to the other end of the fourth resistor, the emitter of the first triode is connected to the positive electrode of the third diode, the negative electrode of the third diode is connected to one end of the fourth capacitor, one end of the second relay, the negative electrode of the fifth diode, and the first input end of the working status indication module. The other end of the second relay is grounded, the positive electrode of the fifth diode is grounded, and the other end of the fourth capacitor is grounded; The distance sensing control module includes a human proximity sensor, a fourth amplifier, a fifth resistor, a second triode, a third relay, and a fourth diode. The power supply end of the human proximity sensor is connected to the output end of the cabinet door opening feedback module, the ground end of the human proximity sensor is grounded, the output end of the human proximity sensor is connected to the in-phase end of the fourth amplifier, the inverting end of the fourth amplifier is connected to the second reference voltage, the output end of the fourth amplifier is connected to the base of the second triode, the collector of the second triode is connected to the power supply voltage through the fifth resistor, the emitter of the second triode is connected to one end of the third relay, the negative electrode of the fourth diode, and the second input end of the working status indication module, the other end of the third relay is grounded, and the positive electrode of the fourth diode is grounded.

2. The safety protection circuit of the power distribution cabinet according to claim 1 is characterized in that: The power distribution module includes a main line, a first switch, a second switch, a third switch, and multiple branch lines. The main line supplies power to the multiple branch lines through the first switch, the second switch, and the third switch in sequence, and a protection unit is provided on each branch line.

3. The safety protection circuit of the power distribution cabinet according to claim 2 is characterized in that: The protection unit includes a current transformer, a first diode, a first capacitor, a seventh resistor, a first amplifier, a fifth switch, a first resistor, a thyristor, a fourth relay, and a second diode. The current transformer samples the current of the branch line. One end of the current transformer is grounded, and the other end of the current transformer is connected to the positive electrode of the first diode. The negative electrode of the first diode is connected to one end of the first capacitor, one end of the seventh resistor, and the in-phase end of the first amplifier. The other end of the first capacitor is grounded, and the other end of the seventh resistor is grounded. The inverting end of the first amplifier is connected to the first reference voltage. The output end of the first amplifier is connected to the control electrode of the thyristor. The positive electrode of the thyristor is connected to one end of the first resistor, and the other end of the first resistor is connected to one end of the fifth switch. The other end of the fifth switch is connected to the power supply voltage. The negative electrode of the thyristor is connected to one end of the fourth relay and the negative electrode of the second diode. The other end of the fourth relay is grounded, and the positive electrode of the second diode is grounded. When the fourth relay is working, the fourth switch on the branch line where the fourth relay is located is controlled to be disconnected.

4. The safety protection circuit of the power distribution cabinet according to claim 1 is characterized in that: The working status indication module includes a sixth diode, a seventh diode, an eighth diode, a fifth AND gate, and a sixth resistor. The positive electrode of the seventh diode is connected to the first output end of the voice prompt control module, the positive electrode of the eighth diode is connected to the first output end of the distance sensing control module, the negative electrode of the seventh diode is connected to the first input end of the fifth AND gate, the negative electrode of the eighth diode is connected to the second input end of the fifth AND gate, the output end of the fifth AND gate is connected to one end of the sixth resistor, the other end of the sixth resistor is connected to the positive electrode of the sixth diode, the negative electrode of the sixth diode is grounded, and the sixth diode, the seventh diode, and the eighth diode are light-emitting diodes.

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