Power line leakage current detection and protection device

Abstract

The present invention discloses a power line leakage current detection and protection device, comprising: a switch unit, which is configured to control the power connection between an input terminal and an output terminal; and a leakage protection unit, which comprises a switch driving module and a leakage detection module, wherein the leakage detection module comprises a first leakage detection line and a second leakage detection line, and the first leakage detection line is connected in series with the second leakage detection line; wherein the switch driving module is configured to control the switch unit to disconnect the power connection according to the leakage current signal detected by the leakage detection module. The present invention ensures the reliability of the power line leakage current detection and protection device by realizing the detection of whether the first leakage detection line and the second leakage detection line are intact.

Description

Technical Field

[0001] The invention relates to the electrical field, and in particular to a power line leakage current detection and protection device. Background Art

[0002] The power line leakage current detection protection device (hereinafter referred to as LCDI) is a fire safety protection device for electricity use. Its main structure is a power line with a plug. Its main function is to detect leakage current between the live wire, neutral wire, etc. of the power line from the power plug to the load electrical appliance (such as air conditioner, dehumidifier) ​​and the wire shielding layer (shield), cut off the power supply of the electrical equipment, prevent the occurrence of fire, and provide safety protection. Prevent arc fault fires caused by damage to the power line and reduced insulation strength due to aging, wear, extrusion or animal gnawing of the live wire, neutral wire, and ground wire in the power line.

[0003] like Figure 1 and Figure 1A The test "TEST" button of the traditional LCDI device shown can only detect whether the internal circuit and tripping mechanism of the device plug are normal, but cannot detect whether the leakage current detection function from the leakage detection line (shielded line) in the external power cord of the plug to the end is normal. When the leakage detection line (shielded line) in the power cord is open, even if the user operates the test "TEST" and reset "RESET" indication functions normally, since the leakage detection line (shielded line) in the power cord is open, it does not have the leakage protection function at this time, there is a serious safety hazard, which may lead to fire.

[0004] Therefore, there is an urgent need for a power line leakage current detection protection device that can detect a leakage detection line. Summary of the invention

[0005] Based on the above problems, the present invention provides a power line leakage current detection protection device, comprising: a switch unit, which is configured to control the power connection between an input terminal and an output terminal; and a leakage protection unit, which includes a switch driving module and a leakage detection module, wherein the leakage detection module includes a first leakage detection line and a second leakage detection line, and the first leakage detection line is connected in series with the second leakage detection line; wherein the switch driving module is configured to control the switch unit to disconnect the power connection according to a leakage current signal detected by the leakage detection module.

[0006] In one embodiment, a test unit is further included, which includes a test switch, which is coupled to the leakage protection unit, and a test circuit is formed by at least the test switch and the leakage protection unit. When the test switch is closed, if the leakage detection module is in a first state, the switch driving module controls the switch unit to disconnect the power connection.

[0007] In one implementation, when the test switch is closed, if the leakage detection module is in the second state, the switch unit maintains the power connection.

[0008] In one embodiment, an insulating structure is further included, wherein the insulating structure surrounds at least one of the first leakage detection line and the second leakage detection line.

[0009] In one embodiment, the insulating structure is integrally formed of rubber and plastic material or is coated with insulating paper and / or cotton.

[0010] In one embodiment, the first leakage detection line and the second leakage detection line respectively cover at least one power supply line of the power supply lines.

[0011] In one implementation, the first leakage detection line surrounds the first power supply line, and the second leakage detection line surrounds the second power supply line.

[0012] In one implementation, the first leakage detection line surrounds the first power supply line and the second power supply line, the insulating structure surrounds the first leakage detection line and the ground line, and the second leakage detection line surrounds the insulating structure.

[0013] In one implementation, the first leakage detection line surrounds the first power supply line, the second power supply line and the third power supply line, the insulating structure surrounds the first leakage detection line and the ground line, and the second leakage detection line surrounds the insulating structure.

[0014] In one implementation, the first leakage detection line and the second leakage detection line are metal braided structures or metal wire winding structures or a combination of metal braided structures and metal wire winding structures.

[0015] In one embodiment, the first leakage detection line and the second leakage detection line are a metal foil coated structure or a combination of a metal braided structure and a metal foil coated structure.

[0016] In one embodiment, one side of the first leakage detection line and / or the second leakage detection line is made of insulating material, and the other side is made of conductive material, and the insulating material is located on the outside.

[0017] The present invention ensures the reliability of the power line leakage current detection protection device by detecting whether the first leakage detection line and the second leakage detection line are intact. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments are shown and explained with reference to the accompanying drawings. These drawings are used to explain the basic principles, and only the aspects necessary for understanding the basic principles are shown. These drawings are not to scale. In the drawings, the same reference numerals represent similar features.

[0019] Figure 1 This is a technical schematic diagram of a traditional LCDI device;

[0020] Figure 1A for Figure 1 A cross-sectional view of a power cord used in;

[0021] Figure 2 A schematic diagram of the appearance structure of a power plug according to an embodiment of the present invention;

[0022] Figure 3A is a cross-sectional view of a first embodiment of a leakage current detection line according to the present invention;

[0023] Figure 3B is a cross-sectional view of a second embodiment of a leakage current detection line according to the present invention;

[0024] Figure 3C is a cross-sectional view of a third embodiment of a leakage current detection line according to the present invention;

[0025] Figure 3D FIG. 4 is a cross-sectional view of a fourth embodiment of a leakage current detection line according to the present invention.

[0026] Figure 4 A schematic diagram of a power line leakage current detection and protection device according to an embodiment of the present invention;

[0027] Figure 5 is a schematic diagram according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In the following specific description of the preferred embodiments, reference will be made to the attached drawings which constitute a part of the present invention. The attached drawings show by way of example specific embodiments that can implement the present invention. The illustrative embodiments are not intended to be exhaustive of all embodiments according to the present invention. It will be appreciated that other embodiments may be utilized, and structural or logical modifications may also be made without departing from the scope of the present invention. Therefore, the following specific description is not restrictive, and the scope of the present invention is limited by the appended claims.

[0029] The terms "include", "comprising" and similar terms used herein should be understood as open terms, i.e., "including / includes but not limited to", indicating that other contents may also be included. The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment", etc.

[0030] The present invention aims to provide a power line leakage current detection protection device, which can detect whether the leakage detection line is open (disconnected) by operating a test switch TEST.

[0031] like Figure 2 As shown, the power line leakage current detection and protection device in the present invention comprises a plug part 1 with a switch unit and an external power line 2, wherein the plug part 1 is also provided with a test switch TEST and a reset switch RESET. Figure 2 In the embodiment shown, the power line 2 includes a live line (L) 21, a neutral line (N) 22, a ground line (G) 23, leakage detection lines (shielded lines) 241 and 242, and an insulating outer sheath 27. The shape of the power line 2 can be circular, and the live line 21, the neutral line 22, and the ground line 23 are respectively covered with insulating layers 21A, 22A, and 23A (such as Figures 3A to 3D shown), in Figure 3A The first method shown to Figure 3C In the third embodiment shown, the leakage detection line 241 and the leakage detection line 242 surround the insulating layers 21A and 22A respectively. It should be understood that the power line 2 can also be a parallel flat line, or the power line 2 can be other shapes that can be processed. It is understandable that in other embodiments, the power line 2 can also include only other signal lines. FIG. 3A to FIG. 3D As shown, the power line 2 also includes a filler 26. The outer surface of the leakage detection line 241 can be covered with an insulating structure 28, while the outer surface of the leakage detection line 242 is not covered with the insulating structure 28 (such as Figure 3A and 3B It should be understood that the outer surface of the leakage detection line 242 may be coated with the insulating structure 28, while the outer surface of the leakage detection line 241 may not be coated with the insulating structure 28 (not shown in the drawings). The leakage detection lines 241 and 242 may be metal (such as copper, aluminum, etc.) braided structures (such as Figure 3A and 3D ), may be a winding structure composed of at least one metal wire (not shown in the figure), may be a metal foil coated structure (such as Figure 3B and 3C The insulating structure 28 can be formed by integrally forming a plastic material, or by covering with a material that meets the electrical insulation properties, such as insulating paper, cotton, etc. The leakage detection lines 241 and 242 can be formed by covering with a single-sided insulating material (i.e., one side is a conductive material and the other side is an insulating material), without the need for a separate insulating structure 28 (such as Figure 3C As shown). The leakage detection line 241 covers at least one power supply line (such as a current-carrying core line of a live line (L) 21, a neutral line (N) 22, etc.). Figure 3DIn the fourth embodiment shown, the leakage detection line 241 can wrap the live wire 21 and the neutral wire 22 at the same time, the bonding structure 28 wraps the leakage detection line 241 and the ground wire 23, and the leakage detection line 242 surrounds the bonding structure 28. It should be understood that the leakage detection line 241 or the leakage detection line 242 can wrap multiple power supply lines (current-carrying core wires) at the same time.

[0032] Figure 4 The power line leakage current detection and protection device 10 is a schematic diagram of the power line leakage current detection and protection device according to an embodiment of the present invention. The power line leakage current detection and protection device 10 comprises: a switch unit 103, which is configured to control the power connection between the input terminal 101 and the output terminal 102; and a leakage protection unit 104, which comprises a switch driving module 104a and a leakage detection module 104b, wherein the leakage detection module 104b comprises a first leakage detection line 104c and a second leakage detection line 104d, and the first leakage detection line 104c is connected in series with the second leakage detection line 104d. The switch driving module 104a is configured to control the switch unit 103 to disconnect the power connection according to the leakage current signal detected by the leakage detection module 104b.

[0033] Figure 5 FIG. 2 is a schematic diagram of an embodiment of the present invention. Figure 5 As shown, the power line leakage current detection protection device also includes a test unit 200, and the test unit 200 includes a resistor R4 (simulated leakage current generating element) and a test switch TEST. One end A of the leakage detection line 242 in the power line 2 is connected to the control circuit R2, and the other end D is connected to one end C of the leakage detection line 241. The other end B of the leakage detection line 241 is connected to the test switch TEST. Therefore, the test switch TEST is coupled to the leakage detection lines 241 and 242. In addition, the B end of the leakage detection line 241 is coupled to the live line L, and the N line is coupled to the A end of the leakage detection line 242 via the solenoid SOL, the thyristor SCR and R2, wherein the control electrode of the thyristor SCR is connected to one end of the capacitor C1, the cathode of the thyristor SCR is connected to the other end of the capacitor C1, and the capacitor C1 is connected in parallel with the resistor R3. In this embodiment, the L line forms a test circuit M through the resistor R4, the test switch TEST, the leakage detection line 241, the leakage detection line 242, the resistors R2, R3, the diode D2, and the solenoid SOL to the N line.

[0034] Normally, the test switch TEST is open. When the leakage detection lines 241 and 242 work normally (not open circuit) or there is no current leakage between the power supply lines 21, 22, 23 and the leakage detection lines 241, 242, the thyristor SCR will not be triggered, and the product will work normally. When the test switch TEST is closed, that is, the test circuit M is a closed loop, a simulated leakage current flows through the test circuit M (at this time, the test unit (R2, test switch, etc.) and the leakage detection lines 241, 242 form a current path, and the leakage detection module is in a state where it can detect the simulated leakage current). The simulated leakage current will increase the voltage across the resistor R3, thereby driving the thyristor SCR to turn on. When the thyristor SCR is turned on, the N line, the solenoid SOL, the thyristor SCR, and the diode D1 to the L line form a tripping circuit, and a large current will be generated on the solenoid SOL, forming a sufficiently large magnetic field to trip the RESET switch and cut off the power supply. If any circuit or component in the leakage detection lines 241 and 242 is open, the test circuit M cannot form a closed loop when the test switch TEST is closed, and no simulated leakage current flows through the test circuit M (at this time, the test unit (R2, test switch, etc.) and the leakage detection lines 241 and 242 do not form a current path, and the leakage detection module is in a state where it cannot detect the simulated leakage current), and the product will not trip, - to warn the user that at least one of the leakage detection lines 241 and / or the leakage detection line 242 may be open. Therefore, the user can detect whether the leakage detection lines 241 and 242 of the power cord are intact by operating the test switch TEST. It can be understood that, depending on the application, it is possible to detect whether any component of the test circuit is working properly.

[0035] By implementing the technical solution of the present invention, it is possible to detect the leakage detection line by manually operating the test switch TEST, thereby improving safety.

[0036] Therefore, although the present invention is described with reference to specific examples, wherein these specific examples are intended to be illustrative only and not limiting of the present invention, it is obvious to those skilled in the art that the disclosed embodiments may be changed, added or deleted without departing from the spirit and scope of the present invention.

Claims

1. A power line leakage current detection and protection device, characterized in that: include: a switch unit configured to control a power connection between the input terminal and the output terminal; and A leakage protection unit, comprising a switch driving module and a leakage detection module, wherein the leakage detection module comprises a first leakage detection line and a second leakage detection line, and the first leakage detection line is connected in series with the second leakage detection line; each leakage detection line is provided with a first end and a second end, the first end and the second end of the first leakage detection line are spaced a distance along the length direction of the first leakage detection line, the first end and the second end of the second leakage detection line are spaced a distance along the length direction of the second leakage detection line, and the first end and the second end of the first leakage detection line and the first end and the second end of the second leakage detection line are in the same current loop; wherein the first ends of the first and second leakage detection lines are closer to the input end than the second ends of the first and second leakage detection lines, and the second ends of the first and second leakage detection lines are closer to the output end than the first ends of the first and second leakage detection lines; The switch driving module is configured to control the switch unit to disconnect the power connection according to the leakage current signal detected by the leakage detection module.

2. The power line leakage current detection and protection device according to claim 1, characterized in that: It also includes a test unit, which includes a test switch, which is coupled to the leakage protection unit, and a test circuit is formed by at least the test switch and the leakage protection unit. When the test switch is closed, if the leakage detection module is in a first state, the switch driving module controls the switch unit to disconnect the power connection; wherein the first state corresponds to the leakage detection module being in a state capable of detecting a simulated leakage current.

3. The power line leakage current detection and protection device according to claim 2, characterized in that: One end of the second leakage detection line is coupled to the switch driving module, the other end of the second leakage detection line is connected to one end of the first leakage detection line, and the other end of the first leakage detection line is coupled to the test switch; when the test switch is closed, if the leakage detection module is in a second state, the switch unit maintains the power connection; wherein the second state corresponds to a state in which the leakage detection module is unable to detect a simulated leakage current.

4. The power line leakage current detection and protection device according to claim 1, characterized in that: An insulating structure is also included, and the insulating structure surrounds at least one of the first leakage detection line and the second leakage detection line.

5. The power line leakage current detection and protection device according to claim 4, characterized in that: The insulating structure is formed in one piece from a rubber-plastic material or is coated with insulating paper and / or cotton.

6. The power line leakage current detection and protection device according to claim 4, characterized in that: The first leakage detection line and the second leakage detection line respectively cover at least one power supply line of the power supply lines.

7. The power line leakage current detection and protection device according to claim 6, characterized in that: The first leakage detection line surrounds the first power supply line, and the second leakage detection line surrounds the second power supply line.

8. The power line leakage current detection and protection device according to claim 6, characterized in that: The first leakage detection line surrounds the first power supply line and the second power supply line, the insulating structure surrounds the first leakage detection line and the ground line, and the second leakage detection line surrounds the insulating structure.

9. The power line leakage current detection and protection device according to claim 6, characterized in that: The first leakage detection line surrounds the first power supply line, the second power supply line and the third power supply line, the insulating structure surrounds the first leakage detection line and the ground line, and the second leakage detection line surrounds the insulating structure.

10. The power line leakage current detection and protection device according to claim 1, characterized in that: The first leakage detection line and the second leakage detection line are metal braided structures or metal wire winding structures or a combination of metal braided structures and metal wire winding structures.

11. The power line leakage current detection and protection device according to claim 1, characterized in that: The first leakage detection line and the second leakage detection line are a metal foil coated structure or a combination of a metal braided structure and a metal foil coated structure.

12. The power line leakage current detection and protection device according to claim 1, characterized in that: One side of the first leakage detection line and / or the second leakage detection line is made of insulating material, and the other side is made of conductive material, and the insulating material is located on the outside.

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