Electric leakage intelligent detection circuit of power switch cabinet

Abstract

The invention discloses an electric leakage intelligent detection circuit of a power switch cabinet, and relates to the field of current detection, and the electric leakage intelligent detection circuit of the power switch cabinet comprises a voltage distribution module which is used for the switch cabinet to supply voltage to a post-stage circuit; the electric leakage sampling module is used for obtaining three sampling voltages when the switch cabinet leaks electricity, and has the beneficial effects that the electric leakage sampling module and the electric leakage detection module are matched, and when the change range of the magnitude of the leakage current is large, a specific detection unit in the electric leakage detection module is selected for detection according to the actual magnitude of the leakage current; the problem that the detection equipment is damaged due to mismatching between the detection equipment and the leakage current is avoided; for the intermittent electric leakage problem and the possibility of misjudgment, in the arranged electric leakage detection module, after a large current detection unit is intermittently triggered, a small current detection unit is driven to work for detection, it is ensured that the small current can be detected in the intermittent period, and the electric leakage problem is found in time.

Description

Technical Field

[0001] The invention relates to the field of current detection, in particular to an intelligent leakage detection circuit for a power switch cabinet. Background Art

[0002] The switch cabinet controls the circuits and distributes power. The cable terminals, lightning arresters, insulating pillars, etc. inside the switch cabinet are very likely to have partial discharges due to manufacturing processes, dirt accumulation, moisture, etc., which will affect power distribution. Therefore, relevant leakage detection equipment is needed.

[0003] Conventional leakage detection equipment is easily damaged when the leakage current is too large, and needs to be improved. Summary of the invention

[0004] The object of the present invention is to provide an intelligent leakage detection circuit for a power switch 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] An intelligent leakage detection circuit for a power switch cabinet, comprising:

[0007] Voltage distribution module, used in switch cabinet to supply voltage to subsequent circuits;

[0008] The leakage sampling module is used to obtain three sampling voltages when the switch cabinet leaks electricity and output them to the leakage detection module;

[0009] The leakage detection module is used to select whether to drive the switch control module and the alarm warning module to work based on the size of the sampling voltage;

[0010] A switch control module is used to disconnect the circuit between the voltage distribution module and the subsequent circuit during operation;

[0011] Alarm warning module, used for buzzer sounding during operation;

[0012] A button trigger module is used to detect whether the leakage detection module is abnormal by pressing a single button;

[0013] The output end of the voltage distribution module is connected to the input end of the leakage sampling module, the output end of the leakage sampling module is connected to the first input end of the leakage detection module, the output end of the leakage detection module is connected to the input end of the switch control module and the input end of the alarm warning module, the output end of the switch control module is connected to the input end of the voltage distribution module, and the output end of the button trigger module is connected to the second input end of the leakage detection module.

[0014] As a further solution of the present invention: the voltage distribution module includes a main live line, a main neutral line, and a first switch, the first end of the first switch is connected to the main live line, the second end of the first switch is connected to the main neutral line, the third end of the first switch is connected to the branch live line, and the fourth end of the first switch is connected to the branch neutral line.

[0015] As a further solution of the present invention: the leakage sampling module includes a mutual inductor, a first diode, a first capacitor, a first resistor, a second resistor, a third resistor, and a fourth resistor. One end of the mutual inductor is connected to the positive electrode of the first diode, and the other end of the mutual inductor is grounded. The negative electrode of the first diode is connected to one end of the first capacitor and one end of the first resistor, and the other end of the first capacitor is grounded. The other end of the first resistor is connected to one end of the second resistor and the first input end (common point A3) of the leakage detection module, the other end of the second resistor is connected to one end of the third resistor and the first input end (common point A2) of the leakage detection module, the other end of the third resistor is connected to one end of the fourth resistor and the first input end (common point A1) of the leakage detection module, and the other end of the fourth resistor is grounded.

[0016] As a further solution of the present invention: the leakage detection module includes:

[0017] The large current detection unit is used to receive the first sampling voltage (at the common point A1) of the leakage sampling module. When the first sampling voltage can turn on the first switch tube (the first MOS tube), the switch control module and the alarm warning module are driven to work; when the first sampling voltage does not turn on the first switch tube, the input switch of the medium current detection unit is controlled to be closed (the fourth MOS tube); when the first sampling voltage intermittently turns on the first switch tube and is insufficient to drive the switch control module and the alarm warning module to work, when the first sampling voltage intermittently reaches the threshold value a number of times sufficient to drive the counter to output a voltage signal, the output switch of the small current detection unit is controlled to be closed (the third MOS tube);

[0018] The medium current detection unit is used to receive the second sampling voltage (at the common point A2) of the leakage sampling module. After the input switch of the medium current detection unit is closed, when the second sampling voltage can turn on the fifth switch tube (fifth MOS tube), the switch control module and the alarm warning module are driven to work; when the second sampling voltage does not turn on the fifth switch tube (fifth MOS tube), the input switch of the small current detection unit is controlled to be closed (eighth MOS tube);

[0019] The small current detection unit is used to receive the third sampling voltage (at the common point A3) of the leakage sampling module. After the input switch and the output switch of the small current detection unit are closed, when the third sampling voltage can turn on the second switch tube (the second MOS tube), the switch control module and the alarm warning module are driven to work;

[0020] The first output end of the large current detection unit is connected to the input end of the medium current detection unit, the second output end of the large current detection unit is connected to the first input end of the small current detection unit, and the output end of the medium current detection unit is connected to the second input end of the small current detection unit.

[0021] As a further solution of the present invention: the high current detection unit includes a fifth resistor, a sixth resistor, a seventh resistor, a first MOS tube, a second diode, a third diode, a third capacitor, a ninth resistor, a tenth resistor, a twenty-second resistor, a second capacitor, a fourth diode, a counter, an eighth resistor, a fourth capacitor, a ninth diode, and a tenth diode. One end of the sixth resistor is connected to the power supply voltage, the other end of the sixth resistor is connected to the D pole of the first MOS tube, the G pole of the first MOS tube is connected to one end of the fifth resistor and one end of the seventh resistor, the other end of the seventh resistor is grounded, the other end of the fifth resistor is connected to the output end of the leakage sampling module, the S pole of the first MOS tube is connected to the positive pole of the second diode and the positive pole of the third diode, and the negative pole of the third diode is connected to one end of the third capacitor and one end of the ninth resistor. , the positive electrode of the ninth diode, the negative electrode of the ninth diode is connected to the input end of the switch control module and the input end of the alarm warning module, the other end of the third capacitor is grounded, the other end of the ninth resistor is connected to one end of the tenth resistor and the input end of the medium current detection unit, the other end of the tenth resistor is grounded, the negative electrode of the second diode is connected to one end of the twenty-second resistor, the other end of the twenty-second resistor is connected to one end of the second capacitor and the positive electrode of the fourth diode, the other end of the second capacitor is grounded, the negative electrode of the fourth diode is connected to the input end of the counter and the output end of the key trigger module, the output end of the counter is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the fourth capacitor and the positive electrode of the tenth diode, the other end of the fourth capacitor is grounded, and the negative electrode of the tenth diode is connected to the first input end of the small current detection unit.

[0022] As a further solution of the present invention: the medium current detection unit includes a fourth MOS tube, a fourteenth resistor, a sixth capacitor, a sixteenth resistor, a fifteenth resistor, a fifth MOS tube, a seventh diode, a twenty-third resistor, and an eighth diode. The S pole of the fourth MOS tube is connected to the output end of the leakage sampling module, the G pole of the fourth MOS tube is connected to the first output end of the large current detection unit, the D pole of the fourth MOS tube is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to one end of the sixth capacitor, one end of the sixteenth resistor, and the G pole of the fifth MOS tube, the other end of the sixth capacitor is grounded, the other end of the sixteenth resistor is grounded, the D pole of the fifth MOS tube is connected to one end of the fifteenth resistor, the other end of the fifteenth resistor is connected to the power supply voltage, the S pole of the fifth MOS tube is connected to the positive pole of the seventh diode, the negative pole of the seventh diode is connected to one end of the twenty-third resistor and the positive pole of the eighth diode, the negative pole of the eighth diode is connected to the input end of the switch control module and the input end of the alarm warning module, and the other end of the twenty-third resistor is connected to the second input end of the small current detection unit.

[0023] As a further solution of the present invention: the small current detection unit includes an eighth MOS tube, an eleventh resistor, a fifth capacitor, a twelfth resistor, a thirteenth resistor, a second MOS tube, a third MOS tube, a fifth diode, and a sixth diode. The S pole of the eighth MOS tube is connected to the output end of the leakage sampling module, the G pole of the eighth MOS tube is connected to the output end of the medium current detection unit, the D pole of the eighth MOS tube is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to one end of the fifth capacitor, one end of the twelfth resistor, and the G pole of the second MOS tube, the other end of the fifth capacitor is grounded, the other end of the twelfth resistor is grounded, the D pole of the second MOS tube is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to the power supply voltage, the S pole of the second MOS tube is connected to the D pole of the third MOS tube, the G pole of the third MOS tube is connected to the second output end of the large current detection module, the S pole of the third MOS tube is connected to the positive pole of the fifth diode, the negative pole of the fifth diode is connected to the positive pole of the sixth diode, and the negative pole of the sixth diode is connected to the input end of the switch control module and the input end of the alarm warning module.

[0024] As a further solution of the present invention: the switch control module includes a nineteenth resistor, a twentieth resistor, a seventh transistor, a first relay, and an eleventh diode, the collector of the seventh transistor is connected to the power supply voltage through the nineteenth resistor, the base of the seventh transistor is connected to one end of the twentieth resistor and the output end of the leakage detection module, the other end of the twentieth resistor is grounded, the emitter of the seventh transistor is connected to one end of the first relay and the cathode of the eleventh diode, the other end of the first relay is grounded, and the anode of the eleventh diode is grounded.

[0025] As a further solution of the present invention: the alarm warning module includes a seventeenth resistor, an eighteenth resistor, a sixth transistor, and a buzzer, the collector of the sixth transistor is connected to the power supply voltage through the seventeenth resistor, the base of the sixth transistor is connected to one end of the eighteenth resistor and the output end of the leakage detection module, the other end of the eighteenth resistor is grounded, the emitter of the sixth transistor is connected to one end of the buzzer, and the other end of the buzzer is grounded.

[0026] As a further solution of the present invention: the key trigger module includes a twenty-first resistor and a second switch, one end of the twenty-first resistor is connected to the power supply voltage, the other end of the twenty-first resistor is connected to one end of the second switch, and the other end of the second switch is connected to the second input end of the leakage detection module.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: the leakage sampling module and the leakage detection module provided in the present invention cooperate with each other. When the leakage current varies in a large range, a specific detection unit (large current, medium current detection unit) in the leakage detection module will be selected for detection according to the actual leakage current size, thereby avoiding the problem of damage to the detection equipment caused by the mismatch between the detection equipment and the leakage current size; for intermittent leakage problems, there is a possibility of misjudgment (for example, natural factors such as lightning strikes and earthquakes, and electromagnetic interference factors such as changes in current size). In the leakage detection module provided, after the large current detection unit is intermittently triggered, the small current detection unit is driven to work for detection, thereby ensuring that the small current can be detected during the intermittent period and the leakage problem is discovered in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a schematic diagram of an intelligent leakage detection circuit for a power switch cabinet.

[0029] Figure 2 This is the schematic diagram of the leakage detection module.

[0030] Figure 3 This is the circuit diagram of the voltage distribution module and the leakage sampling module.

[0031] Figure 4 This is the circuit diagram of the leakage detection module.

[0032] Figure 5 This is the circuit diagram of the switch control module.

[0033] Figure 6 This is the circuit diagram of the alarm warning module.

[0034] Figure 7 This is the circuit diagram of the key trigger module. DETAILED DESCRIPTION

[0035] 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.

[0036] See also Figure 1 , an intelligent leakage detection circuit for a power switch cabinet, comprising:

[0037] Voltage distribution module 1, used for the switch cabinet to supply voltage to the subsequent circuit;

[0038] The leakage sampling module 2 is used to obtain three sampling voltages when the switch cabinet leaks electricity, and output them to the leakage detection module 3;

[0039] The leakage detection module 3 is used to select whether to drive the switch control module 4 and the alarm warning module 5 to work based on the size of the sampled voltage;

[0040] The switch control module 4 is used to disconnect the loop between the voltage distribution module 1 and the subsequent circuit during operation;

[0041] Alarm module 5, used for buzzer SPEAKER to sound a warning during operation;

[0042] A button trigger module 6 is used to detect whether the leakage detection module 3 is abnormal by pressing a single button;

[0043] The output end of the voltage distribution module 1 is connected to the input end of the leakage sampling module 2, the output end of the leakage sampling module 2 is connected to the first input end of the leakage detection module 3, the output end of the leakage detection module 3 is connected to the input end of the switch control module 4 and the input end of the alarm warning module 5, the output end of the switch control module 4 is connected to the input end of the voltage distribution module 1, and the output end of the button trigger module 6 is connected to the second input end of the leakage detection module 3.

[0044] In this example: See Figure 3 The voltage distribution module 1 includes a main live line L, a main neutral line N, and a first switch S1. The first end of the first switch S1 is connected to the main live line L, the second end of the first switch S1 is connected to the main neutral line N, the third end of the first switch S1 is connected to the branch live line (L1, L2), and the fourth end of the first switch S1 is connected to the branch neutral line (N1, N2).

[0045] The first switch S1 is used as a double-pole switch to control whether the main live line L, the main neutral line N and the subsequent circuit are turned on or off. After the first switch S1 is closed, the main live line L and the main neutral line N supply power, and the branch live line and the branch neutral line (L1 and N1 are one group of branch lines, and L2 and N2 are another group of branch lines) serve as branch lines to supply power to the electrical loads.

[0046] In a specific embodiment: Figure 3 There are two branch lines in the system, which can be increased or decreased according to the actual situation.

[0047] In this example: See Figure 3 The leakage sampling module 2 includes a mutual inductor X, a first diode D1, a first capacitor C1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. One end of the mutual inductor X is connected to the positive electrode of the first diode D1, and the other end of the mutual inductor X is grounded. The negative electrode of the first diode D1 is connected to one end of the first capacitor C1 and one end of the first resistor R1. The other end of the first capacitor C1 is grounded. The other end of the first resistor R1 is connected to one end of the second resistor R2 and the first input end (common point A3) of the leakage detection module 3. The other end of the second resistor R2 is connected to one end of the third resistor R3 and the first input end (common point A2) of the leakage detection module 3. The other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the first input end (common point A1) of the leakage detection module 3. The other end of the fourth resistor R4 is grounded.

[0048] When there is no leakage in the line where the main live line L and the main neutral line N are located, the currents of the main live line L and the main neutral line N passing through the transformer X are equal in magnitude and opposite in direction, and the transformer X does not output current; when there is leakage, the transformer X outputs a current signal, which is rectified and filtered by the first diode D1 and the first capacitor C1 to form a voltage signal on the resistor as the sampling voltage, the common point A1 is the first sampling voltage, the common point A2 is the second sampling voltage, and the common point A3 is the third sampling voltage, and the three sampling voltages are output to the leakage detection module 3.

[0049] In another embodiment: the resistor can be replaced with a potentiometer to facilitate the adjustment of the sampling voltage.

[0050] In this example: See Figure 2 and Figure 4 , the leakage detection module 3 includes:

[0051] The large current detection unit 31 is used to receive the first sampling voltage (at the common point A1) of the leakage sampling module 2. When the first sampling voltage can turn on the first switch tube (the first MOS tube V1), the switch control module 4 and the alarm warning module 5 are driven to work; when the first sampling voltage does not turn on the first switch tube, the input switch of the medium current detection unit 32 is controlled to be closed (the fourth MOS tube V4); when the first sampling voltage intermittently turns on the first switch tube and is insufficient to drive the switch control module 4 and the alarm warning module 5 to work, when the first sampling voltage intermittently reaches the threshold value a number of times sufficient to drive the counter U1 to output a voltage signal, the output switch of the small current detection unit 33 is controlled to be closed (the third MOS tube V3);

[0052] The medium current detection unit 32 is used to receive the second sampling voltage (at the common point A2) of the leakage sampling module 2. After the input switch of the medium current detection unit 32 is closed, when the second sampling voltage can turn on the fifth switch tube (fifth MOS tube V5), the switch control module 4 and the alarm warning module 5 are driven to work; when the second sampling voltage does not turn on the fifth switch tube (fifth MOS tube V5), the input switch of the small current detection unit 33 is controlled to be closed (eighth MOS tube V8);

[0053] The small current detection unit 33 is used to receive the third sampling voltage (at the common point A3) of the leakage sampling module 2. After the input switch and the output switch of the small current detection unit 33 are closed, when the third sampling voltage can turn on the second switch tube (the second MOS tube V2), the switch control module 4 and the alarm warning module 5 are driven to work;

[0054] The first output end of the large current detection unit 31 is connected to the input end of the medium current detection unit 32 , the second output end of the large current detection unit 31 is connected to the first input end of the small current detection unit 33 , and the output end of the medium current detection unit 32 is connected to the second input end of the small current detection unit 33 .

[0055] In this example: See Figure 4The large current detection unit 31 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first MOS tube V1, a second diode D2, a third diode D3, a third capacitor C3, a ninth resistor R9, a tenth resistor R10, a twenty-second resistor R22, a second capacitor C2, a fourth diode D4, a counter U1, an eighth resistor R8, a fourth capacitor C4, a ninth diode D9, and a tenth diode D10. One end of the sixth resistor R6 is connected to the power supply voltage VCC, the other end of the sixth resistor R6 is connected to the D pole of the first MOS tube V1, the G pole of the first MOS tube V1 is connected to one end of the fifth resistor R5 and one end of the seventh resistor R7, the other end of the seventh resistor R7 is grounded, the other end of the fifth resistor R5 is connected to the output end of the leakage sampling module 2, the S pole of the first MOS tube V1 is connected to the positive pole of the second diode D2 and the positive pole of the third diode D3, the negative pole of the third diode D3 is connected to one end of the third capacitor C3 and the negative pole of the ninth resistor R9. The negative electrode of the ninth diode D9 is connected to the input end of the switch control module 4 and the input end of the alarm warning module 5, the other end of the third capacitor C3 is grounded, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the input end of the medium current detection unit 32, the other end of the tenth resistor R10 is grounded, the negative electrode of the second diode D2 is connected to one end of the twenty-second resistor R22, the other end of the twenty-second resistor R22 is connected to one end of the second capacitor C2 and the positive electrode of the fourth diode D4, the other end of the second capacitor C2 is grounded, the negative electrode of the fourth diode D4 is connected to the input end of the counter U1 and the output end of the key trigger module 6, the output end of the counter U1 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is connected to one end of the fourth capacitor C4 and the positive electrode of the tenth diode D10, the other end of the fourth capacitor C4 is grounded, and the negative electrode of the tenth diode D10 is connected to the first input end of the small current detection unit 33.

[0056] After the first sampling voltage is input, if the voltage is large enough to turn on the first MOS tube V1, a high level is output through the third diode D3 to drive the switch control module 4 and the alarm warning module 5 to work; if the voltage of the first sampling voltage is small and insufficient to turn on the first MOS tube V1, it indicates that the first sampling voltage is too small at this time. At this time, the voltage on the tenth resistor R10 is small, so that the input switch of the medium current detection unit 32 is closed (the fourth MOS tube V4), triggering the second sampling voltage for detection; if the voltage of the first sampling voltage intermittently turns on the first MOS tube V1, due to the intermittent conduction, the third capacitor C3 cannot store enough electric energy, and the switch control module 4 and the alarm warning module 5 will not be driven to work, and the input switch of the medium current detection unit 32 is closed. Each time the first MOS tube V1 is turned on, the input end of the counter U1 will receive a pulse signal. When it reaches the set value, for example, the decimal counter outputs a high level after receiving ten pulse signals, and controls the output switch of the small current detection unit 33 to be closed (the third MOS tube V3), providing conditions for the small current detection unit 33 to work.

[0057] In another embodiment: a decimal counter is used as an example here, which is not limited in actual use. The counter U1 can also be a ternary counter, a quaternary counter, etc.

[0058] In this example: See Figure 4 The medium current detection unit 32 includes a fourth MOS tube V4, a fourteenth resistor R14, a sixth capacitor C6, a sixteenth resistor R16, a fifteenth resistor R15, a fifth MOS tube V5, a seventh diode D7, a twenty-third resistor R23, and an eighth diode D8. The S pole of the fourth MOS tube V4 is connected to the output end of the leakage sampling module 2, the G pole of the fourth MOS tube V4 is connected to the first output end of the large current detection unit 31, the D pole of the fourth MOS tube V4 is connected to one end of the fourteenth resistor R14, and the other end of the fourteenth resistor R14 is connected to one end of the sixth capacitor C6, one end of the sixteenth resistor R16, and the fifth MO The G pole of the S tube V5 and the other end of the sixth capacitor C6 are grounded, the other end of the sixteenth resistor R16 is grounded, the D pole of the fifth MOS tube V5 is connected to one end of the fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to the power supply voltage VCC, the S pole of the fifth MOS tube V5 is connected to the positive pole of the seventh diode D7, the negative pole of the seventh diode D7 is connected to one end of the twenty-third resistor R23 and the positive pole of the eighth diode D8, the negative pole of the eighth diode D8 is connected to the input end of the switch control module 4 and the input end of the alarm warning module 5, and the other end of the twenty-third resistor R23 is connected to the second input end of the small current detection unit 33.

[0059] After the fourth MOS tube V4 is turned on, the second sampling voltage (common point A2) is input. When the second sampling voltage is sufficient to turn on the fifth MOS tube V5, the switch control module 4 and the alarm warning module 5 are driven to work through the seventh diode D7 and the eighth diode D8; if the second sampling voltage is too small to turn on the fifth MOS tube V5, no current flows through the fifth MOS tube V5 at this time, so that the voltage at the twenty-third resistor R23 is sufficient to control the input switch of the small current detection unit 33 to close (the eighth MOS tube V8), providing a precondition for the small current detection unit 33 to work.

[0060] In another embodiment: the switch tube here is the fifth MOS tube V5, and may also be other types of switch tubes, such as an IGBT tube, a triode, etc.

[0061] In this example: See Figure 4 The small current detection unit 33 includes an eighth MOS tube V8, an eleventh resistor R11, a fifth capacitor C5, a twelfth resistor R12, a thirteenth resistor R13, a second MOS tube V2, a third MOS tube V3, a fifth diode D5, and a sixth diode D6. The S pole of the eighth MOS tube V8 is connected to the output end of the leakage sampling module 2, the G pole of the eighth MOS tube V8 is connected to the output end of the medium current detection unit 32, the D pole of the eighth MOS tube V8 is connected to one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is connected to one end of the fifth capacitor C5, one end of the twelfth resistor R12, and the G pole of the second MOS tube V2. The other end of the fifth capacitor C5 is grounded, the other end of the twelfth resistor R12 is grounded, the D pole of the second MOS tube V2 is connected to one end of the thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to the power supply voltage VCC, the S pole of the second MOS tube V2 is connected to the D pole of the third MOS tube V3, the G pole of the third MOS tube V3 is connected to the second output end of the large current detection module, the S pole of the third MOS tube V3 is connected to the anode of the fifth diode D5, the cathode of the fifth diode D5 is connected to the anode of the sixth diode D6, and the cathode of the sixth diode D6 is connected to the input end of the switch control module 4 and the input end of the alarm warning module 5.

[0062] After the eighth MOS tube V8 and the third MOS tube V3 are turned on, the small current detection unit 33 can work, and the third sampling voltage (at the common point A3) is input. When the third sampling voltage is sufficient to turn on the second MOS tube V2, a high level will be sent to drive the switch control module 4 and the alarm warning module 5 to work.

[0063] It is normal for a certain amount of leakage to exist in the switch cabinet, but the leakage value needs to be within a safe range (generally in mA). In the switch cabinet, leakage may be caused by factors such as equipment aging, insulation damage, and moisture. It is difficult to completely avoid a moderate amount of leakage, but the key is to control the leakage value within a safe range to prevent electrical fires and personal injury. Therefore, under normal conditions, small currents will not be detected, but when intermittent leakage occurs, considering that leakage will aggravate factors such as equipment aging and insulation damage, in this case, the small current detection unit 33 will be triggered by the large current detection unit 31 and the medium current detection unit 32 to work. When the leakage is sufficient to turn on the second MOS tube V2, a high level will be sent to drive the switch control module 4 and the alarm warning module 5 to work.

[0064] Taking into account the problem of component damage, if the counter U1, the eighth resistor R8, the fourth capacitor C4, the third MOS tube V3 and other devices are not set, when there is no leakage (or the leakage is within a safe range and the current is small), the large current detection unit 31 and the medium current detection unit 32 do not work, triggering the fourth MOS tube V4 to turn on, and the small current detection unit 33 to work. At this time, if intermittent leakage occurs, the leakage current is large and there is a possibility of damaging components. Therefore, the counter U1, the eighth resistor R8, the fourth capacitor C4, the third MOS tube V3 and other devices are set to avoid component damage and circuit failure.

[0065] In another embodiment: after the small current detection unit 33 is triggered to work, the leakage current is not enough to drive the switch control module 4 and the alarm warning module 5 to work, and the size of the third sampling voltage is intermittently detected. When the third sampling voltage gradually increases as a whole, it can also be determined that the intermittent leakage causes the leakage of the switch cabinet to worsen, and timely processing is required.

[0066] In this example: See Figure 5 The switch control module 4 includes a nineteenth resistor R19, a twentieth resistor R20, a seventh transistor V7, a first relay J1, and an eleventh diode D11. The collector of the seventh transistor V7 is connected to the power supply voltage VCC through the nineteenth resistor R19, the base of the seventh transistor V7 is connected to one end of the twentieth resistor R20 and the output end of the leakage detection module 3, the other end of the twentieth resistor R20 is grounded, the emitter of the seventh transistor V7 is connected to one end of the first relay J1 and the cathode of the eleventh diode D11, the other end of the first relay J1 is grounded, and the anode of the eleventh diode D11 is grounded.

[0067] When the common point B is at a high level, the seventh transistor V7 is turned on, the first relay J1 is energized and works, and the first switch S1 is controlled to be opened, and the branch line stops supplying power to the power load, so as to avoid leakage affecting the subsequent circuit.

[0068] In another embodiment, the twentieth resistor R20 can be omitted, and the twentieth resistor R20 is a pull-down resistor to prevent the seventh transistor V7 from being mis-turned on.

[0069] In this example: See Figure 6 The alarm module 5 includes a seventeenth resistor R17, an eighteenth resistor R18, a sixth transistor V6, and a buzzer SPEAKER. The collector of the sixth transistor V6 is connected to the power supply voltage VCC through the seventeenth resistor R17, the base of the sixth transistor V6 is connected to one end of the eighteenth resistor R18 and the output end of the leakage detection module 3, the other end of the eighteenth resistor R18 is grounded, the emitter of the sixth transistor V6 is connected to one end of the buzzer SPEAKER, and the other end of the buzzer SPEAKER is grounded.

[0070] When the common point B is at a high level, the sixth transistor V6 is turned on, and the buzzer SPEAKER sounds to remind that the switch cabinet is leaking electricity.

[0071] In another embodiment: the buzzer SPEAKER can be replaced by a prompting device such as a voice chip.

[0072] In this example: See Figure 7 The key trigger module 6 includes a twenty-first resistor R21 and a second switch S2. One end of the twenty-first resistor R21 is connected to the power supply voltage VCC, the other end of the twenty-first resistor R21 is connected to one end of the second switch S2, and the other end of the second switch S2 is connected to the second input end (at the common point A4) of the leakage detection module 3.

[0073] Only when the counter U1, the eighth resistor R8, the fourth capacitor C4, the third MOS tube V3 and other devices work normally can it be guaranteed to be sufficient to trigger the small current detection unit 33 to work and detect intermittent leakage. Therefore, a key trigger module 6 is set to detect whether this part of the circuit is abnormal. The second switch S2 is closed and opened multiple times to send multiple pulse signals to the counter U1, prompting the counter U1 to output a high level. By observing whether the tenth diode D10 emits light, it is determined whether the circuit is abnormal and detect it in time. The second switch S2 is a key switch, which will pop up after being pressed.

[0074] In another embodiment: the second switch S2 can also be an electronic switch, such as a MOS tube, a triode, etc., which can be driven by a single-chip microcomputer or a timer chip to turn on and off multiple times in a short period of time to trigger the counter U1 to output a high level.

[0075] The working principle of the present invention is: the voltage distribution module 1 is used for the switch cabinet to supply voltage to the subsequent circuit; the leakage sampling module 2 is used to obtain three sampling voltages when the switch cabinet leaks, and output them to the leakage detection module 3; the leakage detection module 3 is used to select whether to drive the switch control module 4 and the alarm warning module 5 to work based on the size of the sampling voltage; the switch control module 4 is used to disconnect the loop between the voltage distribution module 1 and the subsequent circuit when working; the alarm warning module 5 is used to make a buzzer SPEAKER sound to prompt when working; the button trigger module 6 is used to detect whether the leakage detection module 3 is abnormal by a single button.

[0076] 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.

[0077] 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. An intelligent leakage detection circuit for a power switch cabinet, characterized in that: The intelligent leakage detection circuit of the power switch cabinet includes: Voltage distribution module, used in switch cabinet to supply voltage to subsequent circuits; The leakage sampling module is used to obtain three sampling voltages when the switch cabinet leaks electricity and output them to the leakage detection module; The leakage detection module is used to select whether to drive the switch control module and the alarm warning module to work based on the size of the sampling voltage; A switch control module is used to disconnect the circuit between the voltage distribution module and the subsequent circuit during operation; Alarm warning module, used for buzzer sounding during operation; A button trigger module is used to detect whether the leakage detection module is abnormal by pressing a single button; The output end of the voltage distribution module is connected to the input end of the leakage sampling module, the output end of the leakage sampling module is connected to the first input end of the leakage detection module, the output end of the leakage detection module is connected to the input end of the switch control module and the input end of the alarm warning module, the output end of the switch control module is connected to the input end of the voltage distribution module, and the output end of the button trigger module is connected to the second input end of the leakage detection module.

2. The intelligent leakage detection circuit for power switch cabinet according to claim 1 is characterized in that: The voltage distribution module includes a main live line, a main neutral line, and a first switch. The first end of the first switch is connected to the main live line, the second end of the first switch is connected to the main neutral line, the third end of the first switch is connected to the branch live line, and the fourth end of the first switch is connected to the branch neutral line.

3. The intelligent leakage detection circuit for power switch cabinet according to claim 1 is characterized in that: The leakage sampling module includes a mutual inductor, a first diode, a first capacitor, a first resistor, a second resistor, a third resistor, and a fourth resistor. One end of the mutual inductor is connected to the positive electrode of the first diode, and the other end of the mutual inductor is grounded. The negative electrode of the first diode is connected to one end of the first capacitor and one end of the first resistor, and the other end of the first capacitor is grounded. The other end of the first resistor is connected to one end of the second resistor and the first input end of the leakage detection module. The other end of the second resistor is connected to one end of the third resistor and the first input end of the leakage detection module. The other end of the third resistor is connected to one end of the fourth resistor and the first input end of the leakage detection module, and the other end of the fourth resistor is grounded.

4. The intelligent leakage detection circuit for power switch cabinet according to claim 1 or 3, characterized in that: The leakage detection module includes: The large current detection unit is used to receive the first sampling voltage of the leakage sampling module. When the first sampling voltage can turn on the first switch tube, the switch control module and the alarm warning module are driven to work; when the first sampling voltage does not turn on the first switch tube, the input switch of the medium current detection unit is controlled to be closed; when the first sampling voltage intermittently turns on the first switch tube and is insufficient to drive the switch control module and the alarm warning module to work, when the first sampling voltage intermittently reaches the threshold number of times sufficient to drive the counter to output a voltage signal, the output switch of the small current detection unit is controlled to be closed; The medium current detection unit is used to receive the second sampling voltage of the leakage sampling module. After the input switch of the medium current detection unit is closed, when the second sampling voltage can turn on the fifth switch tube, the switch control module and the alarm warning module are driven to work; when the second sampling voltage does not turn on the fifth switch tube, the input switch of the small current detection unit is controlled to be closed; A small current detection unit is used to receive the third sampling voltage of the leakage sampling module. After the input switch and the output switch of the small current detection unit are closed, when the third sampling voltage can turn on the second switch tube, the switch control module and the alarm warning module are driven to work; The first output end of the large current detection unit is connected to the input end of the medium current detection unit, the second output end of the large current detection unit is connected to the first input end of the small current detection unit, and the output end of the medium current detection unit is connected to the second input end of the small current detection unit.

5. The intelligent leakage detection circuit for power switch cabinet according to claim 4 is characterized in that: The large current detection unit includes a fifth resistor, a sixth resistor, a seventh resistor, a first MOS tube, a second diode, a third diode, a third capacitor, a ninth resistor, a tenth resistor, a twenty-second resistor, a second capacitor, a fourth diode, a counter, an eighth resistor, a fourth capacitor, a ninth diode, and a tenth diode. One end of the sixth resistor is connected to the power supply voltage, the other end of the sixth resistor is connected to the D pole of the first MOS tube, the G pole of the first MOS tube is connected to one end of the fifth resistor and one end of the seventh resistor, the other end of the seventh resistor is grounded, the other end of the fifth resistor is connected to the output end of the leakage sampling module, the S pole of the first MOS tube is connected to the positive pole of the second diode and the positive pole of the third diode, the negative pole of the third diode is connected to one end of the third capacitor, one end of the ninth resistor, and the ninth diode. The positive electrode of the ninth diode is connected to the input end of the switch control module and the input end of the alarm warning module, the other end of the third capacitor is grounded, the other end of the ninth resistor is connected to one end of the tenth resistor and the input end of the medium current detection unit, the other end of the tenth resistor is grounded, the negative electrode of the second diode is connected to one end of the twenty-second resistor, the other end of the twenty-second resistor is connected to one end of the second capacitor and the positive electrode of the fourth diode, the other end of the second capacitor is grounded, the negative electrode of the fourth diode is connected to the input end of the counter and the output end of the key trigger module, the output end of the counter is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the fourth capacitor and the positive electrode of the tenth diode, the other end of the fourth capacitor is grounded, and the negative electrode of the tenth diode is connected to the first input end of the small current detection unit.

6. The intelligent leakage detection circuit for power switch cabinet according to claim 4 is characterized in that: The medium current detection unit includes a fourth MOS tube, a fourteenth resistor, a sixth capacitor, a sixteenth resistor, a fifteenth resistor, a fifth MOS tube, a seventh diode, a twenty-third resistor, and an eighth diode. The S pole of the fourth MOS tube is connected to the output end of the leakage sampling module, the G pole of the fourth MOS tube is connected to the first output end of the large current detection unit, the D pole of the fourth MOS tube is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to one end of the sixth capacitor, one end of the sixteenth resistor, and the G pole of the fifth MOS tube, the other end of the sixth capacitor is grounded, the other end of the sixteenth resistor is grounded, the D pole of the fifth MOS tube is connected to one end of the fifteenth resistor, the other end of the fifteenth resistor is connected to the power supply voltage, the S pole of the fifth MOS tube is connected to the positive pole of the seventh diode, the negative pole of the seventh diode is connected to one end of the twenty-third resistor and the positive pole of the eighth diode, the negative pole of the eighth diode is connected to the input end of the switch control module and the input end of the alarm warning module, and the other end of the twenty-third resistor is connected to the second input end of the small current detection unit.

7. The intelligent leakage detection circuit for power switch cabinet according to claim 4 is characterized in that: The small current detection unit includes an eighth MOS tube, an eleventh resistor, a fifth capacitor, a twelfth resistor, a thirteenth resistor, a second MOS tube, a third MOS tube, a fifth diode, and a sixth diode. The S pole of the eighth MOS tube is connected to the output end of the leakage sampling module, the G pole of the eighth MOS tube is connected to the output end of the medium current detection unit, the D pole of the eighth MOS tube is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to one end of the fifth capacitor, one end of the twelfth resistor, and the G pole of the second MOS tube, the other end of the fifth capacitor is grounded, the other end of the twelfth resistor is grounded, the D pole of the second MOS tube is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to the power supply voltage, the S pole of the second MOS tube is connected to the D pole of the third MOS tube, the G pole of the third MOS tube is connected to the second output end of the large current detection module, the S pole of the third MOS tube is connected to the positive pole of the fifth diode, the negative pole of the fifth diode is connected to the positive pole of the sixth diode, and the negative pole of the sixth diode is connected to the input end of the switch control module and the input end of the alarm warning module.

8. The intelligent leakage detection circuit for power switch cabinet according to claim 1 is characterized in that: The switch control module includes a nineteenth resistor, a twentieth resistor, a seventh transistor, a first relay, and an eleventh diode. The collector of the seventh transistor is connected to the power supply voltage through the nineteenth resistor, the base of the seventh transistor is connected to one end of the twentieth resistor and the output end of the leakage detection module, the other end of the twentieth resistor is grounded, the emitter of the seventh transistor is connected to one end of the first relay and the negative electrode of the eleventh diode, the other end of the first relay is grounded, and the positive electrode of the eleventh diode is grounded.

9. The intelligent leakage detection circuit for power switch cabinet according to claim 1, characterized in that: The alarm warning module includes a seventeenth resistor, an eighteenth resistor, a sixth transistor, and a buzzer. The collector of the sixth transistor is connected to the power supply voltage through the seventeenth resistor, the base of the sixth transistor is connected to one end of the eighteenth resistor and the output end of the leakage detection module, the other end of the eighteenth resistor is grounded, the emitter of the sixth transistor is connected to one end of the buzzer, and the other end of the buzzer is grounded.

10. The intelligent leakage detection circuit for power switch cabinet according to claim 4, characterized in that: The key trigger module includes a twenty-first resistor and a second switch, one end of the twenty-first resistor is connected to the power supply voltage, the other end of the twenty-first resistor is connected to one end of the second switch, and the other end of the second switch is connected to the second input end of the leakage detection module.

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