CN111900702A - Power line leakage current detection protection device - Google Patents

Abstract

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

Description

Power line leakage current detection and protection device

technical field

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

Background technique

The power line leakage current detection and protection device (hereinafter referred to as LCDI) is a kind of electric fire safety protection device. Its main structure is a power cord with a plug, and its main function is to detect the power supply plug to the load electrical appliances (such as air conditioners, dehumidifiers) Leakage current occurs between the live wire, neutral wire, etc. between the power line and the protective layer (shield) of the wire, cut off the power supply of the electrical equipment, prevent the occurrence of fire, and provide safety protection. Prevent arc fault fire caused by power line damage and insulation strength decline caused by aging, abrasion, extrusion or animal bites in the live wire, neutral wire, and ground wire in the power line.

As shown in Figure 1 and Figure 1A, the "TEST" button of the traditional LCDI device can only detect whether the internal circuit of the device plug and the tripping mechanism are normal, but not the leakage detection wire (shielded wire) in the external power cord of the plug. ) to the end of the leakage current detection function is normal, when the leakage detection wire (shielded wire) in the power line is open, even if the user operates the test "TEST" and reset "RESET" to indicate that the function is normal, due to the leakage detection wire in the power line (shielded wire) line) open circuit, there is no leakage protection function at this time, there is a serious safety hazard, resulting in a fire.

Therefore, there is an urgent need for a power line leakage current detection and protection device capable of detecting the leakage detection line.

SUMMARY OF THE INVENTION

Based on the above problems, the present invention provides a power line leakage current detection and protection device, including: a switch unit configured to control the power connection between an input terminal and an output terminal; and a leakage protection unit, which includes a switch drive 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 and the second leakage detection line are connected in series; 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.

In one embodiment, a test unit is further included, the test unit includes a test switch, the test switch 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 When the test switch is closed, if the leakage detection module is in the first state, the switch driving module controls the switch unit to disconnect the power connection.

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

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

In one embodiment, the insulating structure is integrally formed with a rubber-plastic material or covered with insulating paper and/or cotton.

In an embodiment, the first leakage detection wire and the second leakage detection wire respectively cover at least one power supply wire among the power cables.

In one embodiment, the first leakage detection line surrounds the first power supply line, and the second leakage detection line surrounds the second power supply line.

In an embodiment, the first leakage detection wire surrounds the first power supply wire and the second power supply wire, the insulating structure surrounds the first leakage detection wire and the ground wire, and the second leakage detection wire surrounds the the insulating structure.

In an embodiment, the first leakage detection line surrounds a first power supply line, a second power supply line and a third power supply line, the insulating structure surrounds the first leakage detection line and the ground line, and the second power supply line The leakage detection line surrounds the insulating structure.

In an embodiment, the first leakage detection wire and the second leakage detection wire are a metal braided structure or a metal wire wound structure or a combination of the metal braided structure and the metal wire wound structure.

In an embodiment, the first leakage detection wire and the second leakage detection wire are a metal foil clad structure or a combination of a metal braided structure and a metal foil clad structure.

In one embodiment, one side of the first leakage detection wire and/or the second leakage detection wire is made of insulating material, and the other side is made of conductive material, and the insulating material is located outside.

The present invention ensures the reliability of the power line leakage current detection and protection device by detecting whether the first leakage detection line and the second leakage detection line are in good condition.

Description of drawings

Embodiments are shown and explained with reference to the drawings. The drawings serve to clarify the basic principles, thus showing only the aspects necessary to understand the basic principles. The drawings are not to scale. In the drawings, the same reference numbers refer to similar features.

Fig. 1 is a technical schematic diagram of a traditional LCDI device;

Figure 1A is a cross-sectional view of the power cord used in Figure 1;

FIG. 2 is a schematic diagram of an external structure of a power plug according to an embodiment of the present invention;

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

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

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

3D is a cross-sectional view of a fourth embodiment of a leakage current detection line according to the present invention.

4 is a structural diagram of a power line leakage current detection and protection device according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an embodiment in accordance with the present invention.

Detailed ways

In the following detailed description of the preferred embodiments, reference will be made to the accompanying drawings which form a part hereof. The accompanying drawings show, by way of example, specific embodiments in which the invention can be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. It is to be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the present invention. Therefore, the following detailed description is not intended to be limiting, and the scope of the invention is defined by the appended claims.

The terms "including", "comprising" and similar terms used herein should be understood as open-ended terms, ie "including/including but not limited to", meaning that other content may also be included. The term "based on" is "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment" and so on.

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

As shown in FIG. 2 , the power line leakage current detection and protection device in the present invention includes a plug part 1 with a switch unit and an external power supply line 2 , wherein the plug part 1 is further provided with a test switch TEST and a reset switch RESET. In the embodiment shown in FIG. 2 , the power line 2 includes a live wire (L) 21 , a neutral wire (N) 22 , a ground wire (G) 23 , leakage detection wires (shielded wires) 241 and 242 , and an insulating jacket 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 (as shown in FIGS. 3A to 3D ). In the first method shown in FIG. 3A In the third embodiment shown in FIG. 3C , the leakage detection wire 241 and the leakage detection wire 242 respectively surround the insulating layers 21A and 22A. It should be understood that the power wire 2 may also be a parallel flat wire, or the power wire 2 may Other shapes that can be processed. It can be understood that, in other embodiments, the power line 2 may only include other signal lines. As shown in FIGS. 3A to 3D , the power cord 2 further includes a filler 26 . The outer surface of the leakage detection wire 241 may be covered with the insulating structure 28 while the outer surface of the leakage detection wire 242 is not covered with the insulating structure 28 (as shown in FIGS. 3A and 3B ). It should be understood that the outer surface of the leakage detection wire 242 may also be covered The insulating structure 28 is covered and the outer surface of the leakage detection wire 241 is not covered with the insulating structure 28 (not shown in the drawings). The leakage detection wires 241 and 242 may be a metal (such as copper, aluminum, etc.) braided structure (as shown in Figures 3A and 3D), a winding structure composed of at least one metal wire (not shown in the figure), or a The metal foil cladding structure (as shown in FIGS. 3B and 3C ) can also be a combination of any of the structures. The insulating structure 28 can be integrally formed with a plastic material, or can be formed by wrapping with insulating paper, cotton and other materials that meet electrical insulating properties. The leakage detection lines 241 and 242 can be formed by covering with single-sided insulating material (ie, conductive material on one side and insulating material on the other side), without the need for a separate insulating structure 28 (as shown in FIG. 3C ). The leakage detection wire 241 covers at least one power supply wire (such as a current-carrying core wire such as a live wire (L) 21, a neutral wire (N) 22, etc.). In the fourth embodiment shown in FIG. 3D, the leakage detection wire 241 can be At the same time, the live wire 21 and the neutral wire 22 are wrapped, the junction structure 28 wraps the leakage detection wire 241 and the ground wire 23, and the leakage detection wire 242 surrounds the junction structure 28. It should be understood that the leakage detection wire 241 or the leakage detection wire 242 can wrap multiple wires at the same time. Supply wires (current-carrying cores).

FIG. 4 is a structural diagram of a 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 includes: a switch unit 103 configured to control the power connection between the input terminal 101 and the output terminal 102; and a leakage protection unit 104 including a switch driving module 104a and a leakage detection module 104b, The leakage detection module 104b includes a first leakage detection line 104c and a second leakage detection line 104d, and the first leakage detection line 104c and the second leakage detection line 104d are connected in series. The switch driving module 104a is configured to control the switch unit 103 to disconnect the power according to the leakage current signal detected by the leakage current detection module 104b.

FIG. 5 is a schematic diagram according to an embodiment of the present invention. As shown in FIG. 5 , the power line leakage current detection and protection device further includes a test unit 200. The test unit 200 includes a resistor R4 (an analog 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 The circuit R2 is connected, the other end D is connected to one end C of the leakage detection line 241 , and the other end B of the leakage detection line 241 is connected to the test switch TEST, so the test switch TEST is coupled to the leakage detection lines 241 and 242 . In addition, the B terminal of the leakage detection wire 241 is coupled to the live wire L, and the N wire is coupled to the A terminal of the leakage detection wire 242 via the solenoid SOL, the thyristor SCR and R2, wherein the control electrode of the thyristor SCR is connected to the capacitor One end of C1 is connected, the cathode of the thyristor SCR is connected with 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 the 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, the solenoid SOL to the N line.

Usually, the test switch TEST is turned on. When the leakage detection lines 241 and 242 work normally (not open) or when there is no current leakage between the power supply lines 21, 22, 23 and the leakage detection lines 241 and 242, the thyristor SCR will not is 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 and 242 form a current path, and the leakage detection The module is in a state where the analog leakage current can be detected). The simulated leakage current will increase the voltage across the resistor R3, and then drive the thyristor SCR to conduct. When the thyristor SCR is turned on, the N line, the solenoid SOL, the thyristor SCR, and the diode D1 to the L line A tripping loop is formed, a large current will be generated on the solenoid SOL, and a large enough magnetic field will be formed, so that the RESET switch will trip, and then the power will be cut off. If any circuit or element 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, the test switch, etc.) ) and the leakage detection lines 241, 242 do not form a current path, the leakage detection module is in a state where the simulated leakage current cannot be detected), the product will not trip, - to alert the user that the leakage detection line 241 and/or the leakage detection line 242 At least one of the may have an open circuit condition. Therefore, the user can detect whether the leakage detection lines 241 and 242 of the power line are in good condition by operating the test switch TEST. It can be understood that, according to different applications, it is possible to detect whether any component of the test circuit works normally.

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

Therefore, while the invention has been described with reference to specific examples which are intended to be illustrative only and not limiting of the invention, it will be apparent to those of ordinary skill in the art that, without departing from the On the basis of the spirit and protection scope of the invention, changes, additions or deletions may be made to the disclosed embodiments.

Claims (12)

1. A power line leakage current detection and protection device is characterized in that, comprising: a switch unit configured to control the power connection between the input and the output; 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 and the second leakage detection line connected in series; 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. 2 . The power line leakage current detection and protection device according to claim 1 , further comprising a test unit, the test unit comprising a test switch, the test switch being coupled to the leakage protection unit and being at least controlled by the The test switch and the leakage protection unit constitute a test circuit, when the test switch is closed, if the leakage detection module is in the first state, the switch driving module controls the switch unit to disconnect the power connection . 3 . The power line leakage current detection and protection device according to claim 2 , wherein when the test switch is closed, if the leakage detection module is in the second state, the switch unit maintains the power connection. 4 . . 4 . The power line leakage current detection and protection device according to claim 1 , further comprising an insulating structure, and the insulating structure surrounds at least one of the first leakage detection line and the second leakage detection line. 5 . . 5 . The power line leakage current detection and protection device according to claim 4 , wherein the insulating structure is integrally formed with a rubber-plastic material or covered with insulating paper and/or cotton. 6 . 6 . The power line leakage current detection and protection device according to claim 4 , wherein the first leakage detection line and the second leakage detection line respectively cover at least one power supply line of the power lines. 7 . 7 . The power line leakage current detection and protection device according to claim 6 , wherein the first leakage detection line surrounds the first power supply line, and the second leakage detection line surrounds the second power supply line. 8 . 8 . The power line leakage current detection and protection device according to claim 6 , wherein the first leakage detection line surrounds the first power supply line and the second power supply line, and the insulating structure surrounds the first leakage detection line. 9 . wire and ground wire, and the second leakage detection wire surrounds the insulating structure. 9 . The power line leakage current detection and protection device according to claim 6 , wherein the first leakage detection line surrounds the first power supply line, the second power supply line and the third power supply line, and the insulating structure surrounds the The first leakage detection wire and the ground wire, and the second leakage detection wire surrounds the insulating structure. 10 . The power line leakage current detection and protection device according to claim 1 , wherein the first leakage detection wire and the second leakage detection wire are a metal braided structure or a metal wire winding structure or a metal braided structure and a metal braided structure. 11 . A combination of wire-wound structures. 11 . The power line leakage current detection and protection device according to claim 1 , wherein the first leakage detection line and the second leakage detection line are metal foil wrapping structure or metal braided structure and metal foil wrapping structure 11 . combination of overlay structures. 12. The power line leakage current detection and protection device according to claim 1, wherein 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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