Power distribution cabinet fault protection system

Abstract

The utility model relates to the technical field of power distribution cabinets, and proposes a power distribution cabinet fault protection system, including a phase loss protection circuit, which includes an optocoupler U1, a NAND gate U2, a switch tube Q1 and a contactor U4; the input end of the optocoupler U1 is connected to the power grid, the first output end of the optocoupler U1 is connected to the first input end of the NAND gate U2, the second output end of the optocoupler U1 is connected to the second input end of the NAND gate U2, the third output end of the optocoupler U1 is connected to the third input end of the NAND gate U2, the fourth output end of the optocoupler U1, the fifth output end of the optocoupler U1 and the sixth output end of the optocoupler U1 are all grounded; the output end of the NAND gate U2 is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to a 12V power supply, and the second end of the switch tube Q1 is connected to the contactor U4. Through the above technical solution, the problem of slow response time of the phase loss protection system in the related art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of power distribution cabinets, and specifically to a fault protection system for a power distribution cabinet. Background Art

[0002] A power distribution cabinet is an electrical device used to distribute and control electricity. It usually contains one or more circuit breakers, switches, protection devices and other electrical components to distribute and control the flow of electricity in the power system. In the power system, various uncontrollable factors (such as circuit breaker tripping, line faults, etc.) may cause a fault state in which one or two phases of power are missing. A phase loss fault in the power distribution cabinet may cause the equipment to fail to work properly or even cause a safety accident. Therefore, most existing power distribution cabinets are equipped with a phase loss protection system, which is an electrical device that can detect phase loss faults and automatically disconnect the circuit. It can protect the equipment from damage when a phase loss fault occurs. However, the circuit structure of the existing phase loss protection system is complex and has the problem of slow response time. Utility Model Content

[0003] The utility model provides a distribution cabinet fault protection system, which solves the problem of slow response time of the phase loss protection system in the related technology.

[0004] The technical solution of the utility model is as follows:

[0005] A power distribution cabinet fault protection system, including a phase loss protection circuit, wherein the phase loss protection circuit includes a diode D1, a diode D2, a diode D3, an optical coupler U1, a NAND gate U2, a NOT gate U7, a capacitor C3, a switch tube Q1 and a contactor U4;

[0006] The first input terminal of the optocoupler U1 is used to connect the A-phase electricity, the second input terminal of the optocoupler U1 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the third input terminal of the optocoupler U1, the third input terminal of the optocoupler U1 is used to connect the B-phase electricity, the fourth input terminal of the optocoupler U1 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the fifth input terminal of the optocoupler U1, the fifth input terminal of the optocoupler U1 is used to connect the C-phase electricity, the sixth input terminal of the optocoupler U1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the first input terminal of the optocoupler U1, the anode of the diode D1 is connected to the anode of the diode D2, and the anode of the diode D2 is connected to the anode of the diode D3;

[0007] The first output end of the optical coupler U1 is connected to the first input end of the NAND gate U2, the second output end of the optical coupler U1 is connected to the second input end of the NAND gate U2, the third output end of the optical coupler U1 is connected to the third input end of the NAND gate U2, the first output end of the optical coupler U1, the second output end of the optical coupler U1 and the third output end of the optical coupler U1 are all connected to a 12V power supply; the fourth output end of the optical coupler U1, the fifth output end of the optical coupler U1 and the sixth output end of the optical coupler U1 are all grounded;

[0008] The output end of the NAND gate U2 is connected to the input end of the NOT gate U7, the output end of the NOT gate U7 is grounded through the capacitor C3, the output end of the NOT gate U7 is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to a 12V power supply, the second end of the switch tube Q1 is connected to the first input end of the contactor U4, the second input end of the contactor U4 is grounded, and the contacts of the contactor U4 are connected to three-phase electricity.

[0009] Furthermore, the utility model also includes a phase sequence detection protection circuit, which includes a resistor R9, a capacitor C1, a switch tube Q2, a diode D4, a resistor R8, a resistor R10 and a relay K1;

[0010] The first end of the resistor R9 is used to connect the B-phase power, the second end of the resistor R9 is connected to the control end of the switch tube Q2, the first end of the switch tube Q2 is connected to the first input end of the relay K1, the second end of the switch tube Q2 is connected to the first end of the resistor R10, and the second end of the resistor R10 is used to connect the C-phase power;

[0011] The anode of the diode D4 is used to connect the A-phase electricity, the cathode of the diode D4 is connected to the second input end of the relay K1 through the resistor R8, the first common end of the relay K1 is connected to the B-phase electricity, the second common end of the relay K1 is connected to the C-phase electricity, the first normally closed end of the relay K1 is used to output the B-phase electricity, the first normally open end of the relay K1 is connected to the second normally closed end of the relay K1, the second normally closed end of the relay K1 is used to output the A-phase electricity, and the first normally closed end of the relay K1 is connected to the second normally open end of the relay K1.

[0012] Furthermore, the utility model also includes an over-temperature protection circuit, and the over-temperature protection circuit includes a temperature control switch U5, a switch tube Q3 and a fan U6;

[0013] The first end of the temperature control switch U5 is connected to a 12V power supply, the second end of the temperature control switch U5 is connected to the control end of the switch tube Q3, the first end of the switch tube Q3 is connected to the first power supply end of the fan U6, the second power supply end of the fan U6 is connected to a 12V power supply, and the second end of the switch tube Q3 is grounded.

[0014] Furthermore, the over-temperature protection circuit in the present utility model further includes a resistor R14, a light-emitting diode LED1, a light-emitting diode LED2 and a diode D8;

[0015] The first end of the resistor R14 is connected to a 12V power supply, the second end of the resistor R14 is connected to the anode of the light-emitting diode LED2, the cathode of the light-emitting diode LED2 is grounded, the second end of the resistor R14 is connected to the anode of the diode D8, the cathode of the diode D8 is connected to the first end of the switch tube Q3, the anode of the light-emitting diode LED1 is connected to the 12V power supply, and the cathode of the light-emitting diode LED1 is connected to the anode of the diode D8.

[0016] Furthermore, the utility model also includes a controller, the phase loss protection circuit is connected to the controller, and the phase loss protection circuit also includes a resistor R6, a resistor R7 and an optical coupler U3;

[0017] The first end of the resistor R6 is connected to the first end of the switch tube Q1, the second end of the resistor R6 is grounded through the resistor R7, the second end of the resistor R6 is connected to the first input end of the optocoupler U3, the second input end of the optocoupler U3 is grounded, the first output end of the optocoupler U3 is connected to a 3.3V power supply, and the second output end of the optocoupler U3 is connected to the controller.

[0018] Furthermore, the utility model also includes a communication unit, and the controller is communicatively connected with the remote terminal via the communication unit.

[0019] The working principle and beneficial effects of the utility model are:

[0020] In the utility model, the phase loss protection circuit is used to detect whether there is a phase loss fault in the power distribution cabinet, and disconnect the connection between the power grid and the power-consuming equipment when a phase loss fault occurs in the power distribution cabinet. The working principle of the phase loss protection circuit is:

[0021] When the three-phase power connected to the power distribution cabinet is normal, the three independent optocouplers inside the optocoupler U1 are turned on alternately, and the NAND gate U2 outputs a high level, which is inverted to a low level by the NAND gate U7, the switch tube Q1 is turned off, and the contactor U4 does not operate, which indicates that the power supply of the power distribution cabinet is normal. Assuming that phase A is missing, the optocouplers corresponding to the first input terminal of the optocoupler U1 and the second input terminal of the optocoupler U1 are turned off, and the first input terminal of the NAND gate U2 is high. At this time, the line voltage in the three-phase power is only U BCOne phase, when the line voltage U BC When crossing the zero point, the other optocouplers inside the optocoupler U1 are also cut off. At this time, the three input terminals of the NAND gate U2 are all high level, and the NAND gate U2 outputs a low level, which is inverted by the NOT gate U7 and converted to a high level. The high level controls the switch tube Q1 to turn on and charges the capacitor C3 at the same time. The charging voltage on C3 can maintain the switch tube Q1 in the on state. After the switch tube Q1 is turned on, the contactor U4 is energized, and the normally closed contacts of the contactor U4 are disconnected, that is, the connection between the power grid and the electrical equipment is disconnected.

[0022] The phase loss protection circuit in the utility model is mainly composed of an optocoupler, a gate circuit (digital circuit) and a switch tube. Compared with the traditional phase loss protection system structure, the circuit structure of the utility model is simple; when detecting the phase loss fault of the distribution cabinet, the traditional phase loss protection system is mostly implemented through analog circuits, while the utility model is implemented by combining an optocoupler with a digital circuit, and the circuit has a fast response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Figure 1 A structural block diagram of a power distribution cabinet fault protection system provided by an embodiment of the present utility model;

[0025] Figure 2 A circuit diagram of a phase loss protection circuit provided in an embodiment of the utility model;

[0026] Figure 3 A circuit diagram of a phase sequence detection protection circuit provided in an embodiment of the utility model;

[0027] Figure 4 A circuit diagram of an over-temperature protection circuit provided in one embodiment of the utility model. DETAILED DESCRIPTION

[0028] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0029] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0030] Example 1

[0031] like Figure 1-2 As shown, this embodiment proposes a distribution cabinet fault protection system, including a phase loss protection circuit, which includes a diode D1, a diode D2, a diode D3, an optocoupler U1, a NAND gate U2, a NOT gate U7, a capacitor C3, a switch tube Q1 and a contactor U4; the first input end of the optocoupler U1 is used to connect the A phase electricity, the second input end of the optocoupler U1 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the third input end of the optocoupler U1, the third input end of the optocoupler U1 is used to connect the B phase electricity, the fourth input end of the optocoupler U1 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the fifth input end of the optocoupler U1, the fifth input end of the optocoupler U1 is used to connect the C phase electricity, the sixth input end of the optocoupler U1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the first input end of the optocoupler U1, the anode of the diode D1 is connected to the anode of the diode D2, and the diode The anode of D2 is connected to the anode of diode D3; the first output end of the optocoupler U1 is connected to the first input end of the NAND gate U2, the second output end of the optocoupler U1 is connected to the second input end of the NAND gate U2, the third output end of the optocoupler U1 is connected to the third input end of the NAND gate U2, the first output end of the optocoupler U1, the second output end of the optocoupler U1 and the third output end of the optocoupler U1 are all connected to a 12V power supply; the fourth output end of the optocoupler U1, the fifth output end of the optocoupler U1 and the sixth output end of the optocoupler U1 are all grounded; the output end of the NAND gate U2 is connected to the input end of the NAND gate U7, the output end of the NAND gate U7 is grounded through the capacitor C3, the output end of the NAND gate U7 is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to the 12V power supply, the second end of the switch tube Q1 is connected to the first input end of the contactor U4, the second input end of the contactor U4 is grounded, and the contacts of the contactor U4 are connected to three-phase electricity.

[0032] A phase failure in a power distribution cabinet refers to a situation where one or more phases in the power distribution cabinet are disconnected or have poor contact, causing the circuit to fail to work properly. This failure may be caused by the following reasons:

[0033] Poor contact of electrical equipment: The connectors, switches, contactors and other components of the electrical equipment have poor contact, resulting in circuit disconnection.

[0034] Wire disconnection: Due to aging, wear, corrosion and other reasons, the wire is disconnected, making the circuit unable to work normally.

[0035] Fuse blown: When an overload or short circuit occurs in the circuit, the fuse will blow to protect the circuit, but it will also cause a phase failure.

[0036] Transformer failure: The transformer is an important device in the power distribution cabinet. If the transformer fails, one or several phases of the circuit may be disconnected.

[0037] Misoperation: When performing maintenance or operation on the power distribution cabinet, a phase circuit is disconnected by mistake, resulting in a fault.

[0038] A phase failure in a power distribution cabinet can lead to unstable power supply, equipment failure, and other problems, and in serious cases may even cause safety accidents. Therefore, in order to avoid safety accidents, when a phase failure occurs in the power distribution cabinet, the connection between the power grid and the power-consuming equipment should be disconnected in time.

[0039] In this embodiment, the phase loss protection circuit is used to detect whether there is a phase loss fault in the power distribution cabinet, and disconnect the connection between the power grid and the power-consuming equipment when a phase loss fault occurs in the power distribution cabinet. Specifically, the working principle of the phase loss protection circuit is:

[0040] When the three-phase electricity connected to the distribution cabinet is normal, phase A leads phase B by 120°, phase B leads phase C by 120°, and phase C leads phase A by 120°. Three independent optocouplers are integrated inside the optocoupler U1. According to the voltage waveform of the three-phase electricity, it can be seen that under normal circumstances, the three independent optocouplers inside the optocoupler U1 are alternately turned on. Assuming that at any time the voltage of phase A is greater than the voltage of phase C, and the voltage of phase C is greater than the voltage of phase B, the output current signal of phase A is transmitted through the first input terminal of the optocoupler U1. And the second input end of the optocoupler U1, because the voltage of phase B is the smallest at this moment, therefore, the current output from the second input end of the optocoupler U1 flows to phase B after passing through the diode D2, thus forming a loop. At this time, the optocoupler and diode D2 corresponding to the first and second input ends of the optocoupler U1 are turned on, and the first output end of the optocoupler U1 outputs a low level. Therefore, the NAND gate U2 outputs a high level, which is inverted to a low level after being inverted by the NOT gate U7. The switch tube Q1 is cut off, and the contactor U4 does not work. At this time, it indicates that the power supply of the distribution cabinet is normal.

[0041] Assume that when phase A is missing, the optocouplers corresponding to the first input terminal of optocoupler U1 and the second input terminal of optocoupler U1 are cut off, and the first input terminal of NAND gate U2 is at a high level. At this time, the line voltage in the three-phase power is only U BC One phase, when the line voltage U BCWhen crossing the zero point, the other optocouplers inside the optocoupler U1 are also cut off. At this time, the three input terminals of the NAND gate U2 are all high level, and the NAND gate U2 outputs a low level, which is inverted by the NOT gate U7 and converted to a high level. The high level controls the switch tube Q1 to turn on and charges the capacitor C3 at the same time. The charging voltage on C3 can maintain the switch tube Q1 in the on state. After the switch tube Q1 is turned on, the contactor U4 is energized, and the normally closed contacts of the contactor U4 are disconnected, that is, the connection between the power grid and the electrical equipment is disconnected.

[0042] The phase loss protection circuit in this embodiment is mainly composed of an optocoupler, a gate circuit (digital circuit) and a switch tube. Compared with the traditional phase loss protection system structure, the circuit structure of this embodiment is simple. When detecting a phase loss fault in a distribution cabinet, the traditional phase loss protection system mostly uses analog circuits to implement it, while this embodiment is implemented by combining an optocoupler with a digital circuit, and the circuit has a fast response speed.

[0043] like Figure 3 As shown, the present embodiment also includes a phase sequence detection protection circuit, which includes a resistor R9, a capacitor C1, a switch tube Q2, a diode D4, a resistor R8, a resistor R10 and a relay K1; the first end of the resistor R9 is used to connect the B phase electricity, the second end of the resistor R9 is connected to the control end of the switch tube Q2, the first end of the switch tube Q2 is connected to the first input end of the relay K1, the second end of the switch tube Q2 is connected to the first end of the resistor R10, and the second end of the resistor R10 is used to connect the C phase electricity; the anode of the diode D4 is used to connect the A phase electricity, the cathode of the diode D4 is connected to the second input end of the relay K1 through the resistor R8, the first common end of the relay K1 is connected to the B phase electricity, the second common end of the relay K1 is connected to the C phase electricity, the first normally closed end of the relay K1 is used to output the B phase electricity, the first normally open end of the relay K1 is connected to the second normally closed end of the relay K1, the second normally closed end of the relay K1 is used to output the A phase electricity, and the first normally closed end of the relay K1 is connected to the second normally open end of the relay K1.

[0044] Failure of transformers, circuit breakers and other equipment in the power supply system may cause the phase sequence to be reversed. Reverse phase sequence will affect the electrical equipment connected to the power distribution cabinet. If the electrical equipment connected to the power distribution cabinet is a motor, the following conditions may occur when the phase sequence of the power distribution cabinet fails:

[0045] Motor reversal: The rotation direction of a three-phase motor is related to the phase sequence. When the phase sequence is reversed, the motor's rotation direction will also change. This may cause the equipment to not work properly and may even cause a safety accident.

[0046] The motor cannot start: In some cases, the reverse operation of the three-phase motor may cause the motor to fail to start. This is because the starting torque of the motor is related to the phase sequence. The reverse phase sequence may cause the starting torque to decrease, making the motor unable to start normally.

[0047] Unstable motor operation: When a three-phase motor runs in reverse order, it may experience unstable operation, such as speed fluctuations, vibrations, etc. This will not only affect the normal operation of the equipment, but may also cause damage to the equipment.

[0048] Motor overheating: When a three-phase motor is running in reverse order, its internal current may be abnormal, causing the motor to overheat. Long-term overheating may damage the insulation material of the motor and shorten the service life of the motor.

[0049] In order to avoid these consequences, the phase sequence of the three-phase motor should be ensured to be correct. In this embodiment, the phase sequence detection protection circuit is used to detect the phase sequence of the three-phase power connected to the distribution cabinet. When there is a problem with the phase sequence of the distribution cabinet, the faulty phase sequence can be automatically corrected. Thereby ensuring the normal operation of the motor. The working principle of the phase sequence detection protection circuit is:

[0050] Resistor R9 and capacitor C1 form a RC step-down circuit. When the phase sequence of the distribution cabinet is correct, the switch tube Q2 is cut off and the relay K1 does not operate. Assuming that phase A and phase B are connected reversely, the switch tube Q2 is turned on, the relay K1 is energized and attracted, and the contacts of relay K1 operate to automatically swap the phase sequence of phase A and phase B to ensure the normal operation of the motor.

[0051] like Figure 4 As shown, this embodiment also includes an over-temperature protection circuit, which includes a temperature control switch U5, a switch tube Q3 and a fan U6; the first end of the temperature control switch U5 is connected to a 12V power supply, the second end of the temperature control switch U5 is connected to the control end of the switch tube Q3, the first end of the switch tube Q3 is connected to the first power supply end of the fan U6, the second power supply end of the fan U6 is connected to the 12V power supply, and the second end of the switch tube Q3 is grounded.

[0052] The over-temperature fault of the power distribution cabinet refers to the fault state in which the internal temperature of the power distribution cabinet exceeds the safe operating temperature, resulting in damage to the equipment or failure to work normally. Over-temperature faults are usually caused by the following reasons:

[0053] Poor heat dissipation: The electrical equipment inside the distribution cabinet will generate heat when working. If the heat dissipation is poor, the temperature will rise.

[0054] Overload operation: When the electrical equipment in the distribution cabinet is overloaded, it will generate excessive heat, causing the temperature to rise.

[0055] Internal short circuit: When a short circuit occurs in the electrical equipment inside the distribution cabinet, a large amount of heat will be generated, causing the temperature to rise sharply.

[0056] In order to prevent the over-temperature failure of the power distribution cabinet, this embodiment adds an over-temperature protection circuit to detect the ambient temperature of the power distribution cabinet. When the ambient temperature of the power distribution cabinet exceeds the set value, the power distribution cabinet is automatically cooled down. Specifically, the working principle of the over-temperature protection circuit is as follows:

[0057] The temperature control switch U5 is used to detect the ambient temperature of the distribution cabinet. When the ambient temperature of the distribution cabinet is lower than the set value, the temperature control switch U5 is disconnected, the switch tube Q3 is cut off, and the fan U6 does not work; when the ambient temperature of the distribution cabinet is higher than the set value, the temperature control switch U5 is closed, the switch tube Q3 is turned on, and the fan U6 is energized. The fan U6 is used to dissipate heat for the distribution cabinet. When the temperature is lower than the set value, the temperature control switch U5 is disconnected.

[0058] like Figure 4 As shown, the over-temperature protection circuit in this embodiment also includes a resistor R14, a light-emitting diode LED1, a light-emitting diode LED2 and a diode D8; the first end of the resistor R14 is connected to a 12V power supply, the second end of the resistor R14 is connected to the anode of the light-emitting diode LED2, the cathode of the light-emitting diode LED2 is grounded, the second end of the resistor R14 is connected to the anode of the diode D8, the cathode of the diode D8 is connected to the first end of the switch tube Q3, the anode of the light-emitting diode LED1 is connected to the 12V power supply, and the cathode of the light-emitting diode LED1 is connected to the anode of the diode D8.

[0059] In this embodiment, when the ambient temperature of the distribution cabinet is lower than the set value, the switch tube Q3 is cut off and the light-emitting diode LED2 emits a green light signal. When the ambient temperature of the distribution cabinet is higher than the set value, the switch tube Q3 is turned on, and the first end of the switch tube Q3 is considered to be grounded. At this time, the light-emitting diode LED2 is short-circuited by the diode D8, and the light-emitting diode LED1 emits a red light signal. Therefore, by judging the on and off status of the light-emitting diodes LED1 and LED2, it can be judged whether the distribution cabinet is overheated.

[0060] like Figure 1 As shown, the present embodiment also includes a controller, the phase loss protection circuit is connected to the controller, and the phase loss protection circuit also includes a resistor R6, a resistor R7 and an optocoupler U3; the first end of the resistor R6 is connected to the first end of the switch tube Q1, the second end of the resistor R6 is grounded through the resistor R7, the second end of the resistor R6 is connected to the first input end of the optocoupler U3, the second input end of the optocoupler U3 is grounded, the first output end of the optocoupler U3 is connected to a 3.3V power supply, and the second output end of the optocoupler U3 is connected to the controller.

[0061] In order to better maintain the power system and ensure the normal power consumption of users, a controller is added in this embodiment to store the number of fault occurrences and historical records, providing an effective basis for the maintenance of the distribution cabinet.

[0062] Among them, the resistor R6 and the resistor R7 form a voltage divider circuit. When the power distribution cabinet does not have a phase loss, the switch tube Q1 is turned off. After the voltage is divided by the resistor R6 and the resistor R7, the optical coupler 3 is turned on, and the second output end of the optical coupler U3 outputs a 3.3V high-level signal to the controller. When the power distribution cabinet lacks a phase, the switch tube Q1 is turned on, and the voltage on the resistor R7 is reduced, the optical coupler U3 is turned off, and the second output end of the optical coupler U3 outputs a low-level signal to the controller. The controller U3 can determine the fault condition of the power distribution cabinet according to the electrical signal output by the optical coupler U3.

[0063] Similarly, by judging the electrical signals at the first end of the switch tube Q2 and the first end of the switch tube Q3, it can be determined whether the power distribution cabinet has a phase sequence fault and an over-temperature fault.

[0064] like Figure 1 As shown, this embodiment also includes a communication unit, and the controller is connected to the remote terminal through the communication unit.

[0065] In this embodiment, a communication unit is also added, and the communication unit in this embodiment can be a wired communication method or a wireless communication method. The controller is used to detect whether there is a phase failure, phase sequence failure, and over-temperature failure in the power distribution cabinet, and transmit the detected fault signal to the remote terminal through the communication unit, thereby realizing an unattended real-time detection method.

[0066] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. The power distribution cabinet fault protection system is characterized by: It includes a phase loss protection circuit, which includes a diode D1, a diode D2, a diode D3, an optocoupler U1, a NAND gate U2, a NOT gate U7, a capacitor C3, a switch tube Q1 and a contactor U4; The first input terminal of the optocoupler U1 is used to connect the A-phase electricity, the second input terminal of the optocoupler U1 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the third input terminal of the optocoupler U1, the third input terminal of the optocoupler U1 is used to connect the B-phase electricity, the fourth input terminal of the optocoupler U1 is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the fifth input terminal of the optocoupler U1, the fifth input terminal of the optocoupler U1 is used to connect the C-phase electricity, the sixth input terminal of the optocoupler U1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the first input terminal of the optocoupler U1, the anode of the diode D1 is connected to the anode of the diode D2, and the anode of the diode D2 is connected to the anode of the diode D3; The first output end of the optical coupler U1 is connected to the first input end of the NAND gate U2, the second output end of the optical coupler U1 is connected to the second input end of the NAND gate U2, the third output end of the optical coupler U1 is connected to the third input end of the NAND gate U2, the first output end of the optical coupler U1, the second output end of the optical coupler U1 and the third output end of the optical coupler U1 are all connected to a 12V power supply; the fourth output end of the optical coupler U1, the fifth output end of the optical coupler U1 and the sixth output end of the optical coupler U1 are all grounded; The output end of the NAND gate U2 is connected to the input end of the NOT gate U7, the output end of the NOT gate U7 is grounded through the capacitor C3, the output end of the NOT gate U7 is connected to the control end of the switch tube Q1, the first end of the switch tube Q1 is connected to a 12V power supply, the second end of the switch tube Q1 is connected to the first input end of the contactor U4, the second input end of the contactor U4 is grounded, and the contacts of the contactor U4 are connected to three-phase electricity.

2. The power distribution cabinet fault protection system according to claim 1, characterized in that: It also includes a phase sequence detection protection circuit, which includes a resistor R9, a capacitor C1, a switch tube Q2, a diode D4, a resistor R8, a resistor R10 and a relay K1; The first end of the resistor R9 is used to connect the B-phase power, the second end of the resistor R9 is connected to the control end of the switch tube Q2, the first end of the switch tube Q2 is connected to the first input end of the relay K1, the second end of the switch tube Q2 is connected to the first end of the resistor R10, and the second end of the resistor R10 is used to connect the C-phase power; The anode of the diode D4 is used to connect the A-phase electricity, the cathode of the diode D4 is connected to the second input end of the relay K1 through the resistor R8, the first common end of the relay K1 is connected to the B-phase electricity, the second common end of the relay K1 is connected to the C-phase electricity, the first normally closed end of the relay K1 is used to output the B-phase electricity, the first normally open end of the relay K1 is connected to the second normally closed end of the relay K1, the second normally closed end of the relay K1 is used to output the A-phase electricity, and the first normally closed end of the relay K1 is connected to the second normally open end of the relay K1.

3. The power distribution cabinet fault protection system according to claim 1, characterized in that: It also includes an over-temperature protection circuit, which includes a temperature control switch U5, a switch tube Q3 and a fan U6; The first end of the temperature control switch U5 is connected to a 12V power supply, the second end of the temperature control switch U5 is connected to the control end of the switch tube Q3, the first end of the switch tube Q3 is connected to the first power supply end of the fan U6, the second power supply end of the fan U6 is connected to a 12V power supply, and the second end of the switch tube Q3 is grounded.

4. The power distribution cabinet fault protection system according to claim 3, characterized in that: The over-temperature protection circuit also includes a resistor R14, a light-emitting diode LED1, a light-emitting diode LED2 and a diode D8; The first end of the resistor R14 is connected to a 12V power supply, the second end of the resistor R14 is connected to the anode of the light-emitting diode LED2, the cathode of the light-emitting diode LED2 is grounded, the second end of the resistor R14 is connected to the anode of the diode D8, the cathode of the diode D8 is connected to the first end of the switch tube Q3, the anode of the light-emitting diode LED1 is connected to the 12V power supply, and the cathode of the light-emitting diode LED1 is connected to the anode of the diode D8.

5. The power distribution cabinet fault protection system according to claim 1, characterized in that: It also includes a controller, the phase loss protection circuit is connected to the controller, and the phase loss protection circuit also includes a resistor R6, a resistor R7 and an optical coupler U3; The first end of the resistor R6 is connected to the first end of the switch tube Q1, the second end of the resistor R6 is grounded through the resistor R7, the second end of the resistor R6 is connected to the first input end of the optocoupler U3, the second input end of the optocoupler U3 is grounded, the first output end of the optocoupler U3 is connected to a 3.3V power supply, and the second output end of the optocoupler U3 is connected to the controller.

6. The power distribution cabinet fault protection system according to claim 5, characterized in that: It also includes a communication unit, and the controller is connected to the remote terminal through the communication unit.

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