CN111900702A

CN111900702A - Power line leakage current detection protection device

Info

Publication number: CN111900702A
Application number: CN201910367054.4A
Authority: CN
Inventors: 李成力; 李永森; 聂胜云
Original assignee: Suzhou Ele Mfg Co ltd
Current assignee: Suzhou Ele Mfg Co ltd
Priority date: 2019-05-05
Filing date: 2019-05-05
Publication date: 2020-11-06

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 protection device

Technical Field

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

Background

The power line leakage current detection and protection device (LCDI) is an electric fire safety protection device, and the main structure of the device is a power line with a plug, and the device has the main functions of detecting leakage current between a live wire, a zero wire and the like of the power line between a power supply plug and a load electrical appliance (such as an air conditioner and a dehumidifier) and a lead protection layer (shield), cutting off the power supply of the electrical appliance, preventing fire from generating and providing safety protection. The electric arc fault fire caused by power line damage and insulation strength reduction caused by aging, abrasion, extrusion or animal biting of a live wire, a zero wire and a ground wire in the power line is prevented.

The TEST "button of the conventional LCDI device shown in fig. 1 and 1A can only detect whether the internal circuit and the trip mechanism of the plug of the device are normal, but does not detect whether the leakage current detection function from the leakage detection line (shield line) to the end of the power line outside the plug is normal, and when the leakage detection line (shield line) in the power line is open, even if the user operates the TEST" and the RESET "indicating function is normal, since the leakage detection line (shield line) in the power line is open, the leakage protection function is not provided at this time, there is a serious safety hazard, resulting in the occurrence of fire.

Therefore, a power line leakage current detection protection device capable of detecting a leakage detection line is needed.

Disclosure of Invention

Based on the above problem, the present invention provides a power line leakage current detection protection device, which includes: a switching unit configured to control a power connection between the input terminal and the output terminal; and a leakage protection unit including 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 are connected in series; wherein the switch driving module is configured to control the switching unit to disconnect the power connection according to a leakage current signal detected by the leakage detecting module.

In one embodiment, the testing unit further comprises a testing switch coupled to the leakage protection unit and forming a testing circuit with at least the testing switch and the leakage protection unit, and when the testing switch is closed, if the leakage detection module is in a first state, the switch driving module controls the switching unit to disconnect the power connection.

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

In one embodiment, further comprising an insulating structure surrounding at least one of the first and second leakage detection lines.

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

In one embodiment, the first and second leakage detection lines each cover at least one power supply line of the power supply lines.

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 one embodiment, the first leakage detection line surrounds a first power supply line and a second power supply line, the insulating structure surrounds the first leakage detection line and a ground line, and the second leakage detection line surrounds the insulating structure.

In one 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 a ground line, and the second leakage detection line surrounds the insulating structure.

In one embodiment, the first and second leakage detecting lines are metal braided structures or metal wire wound structures or a combination of metal braided structures and metal wire wound structures.

In one embodiment, the first and second leakage detecting lines are metal foil clad structures or a combination of metal braided structures and metal foil clad structures.

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

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.

Drawings

Embodiments are shown and described with reference to the drawings. These drawings are provided to illustrate the basic principles and thus only show the aspects necessary for understanding the basic principles. The figures are not to scale. In the drawings, like reference numerals designate similar features.

FIG. 1 is a technical schematic diagram of a conventional LCDI apparatus;

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

FIG. 2 is a schematic diagram of an embodiment of a power plug;

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

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

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

fig. 3D is a cross-sectional view of a fourth embodiment of the leakage current detecting wire according to the present invention.

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

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

Detailed Description

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

As used herein, the terms "include," "include," and similar terms are to be construed as open-ended terms, i.e., "including/including but not limited to," meaning that additional content can be included as well. 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 the like.

The invention aims to provide a power line leakage current detection protection device, which can detect whether a leakage detection line is open (disconnected) or not by operating a TEST switch TEST.

As shown in fig. 2, the power line leakage current detection protection device of the present invention includes a plug portion 1 with a switch unit and an external power line 2, wherein the plug portion 1 is further provided with a TEST switch TEST and a RESET switch RESET. In the embodiment shown in fig. 2, the power supply line 2 includes a live line (L)21, a neutral line (N)22, a ground line (G)23, leakage detection lines (shield lines) 241 and 242, and an insulating outer cover 27. The power cord 2 may be round in shape, with the live, neutral and

ground wires

21, 22 and 23 being coated with

insulating layers

21A, 22A and 23A, respectively (as shown in fig. 3A to 3D), and in the first to third embodiments shown in fig. 3A to 3C, the

leakage detection line

241 and 242 surround the

insulating layers

21A and 22A, respectively, it should be understood that the power cord 2 may also be flat wires side by side, or the power cord 2 may be in other finished shapes. It is understood that in other embodiments, only other signal lines may be included in the power supply line 2. As shown in fig. 3A to 3D, the power supply line 2 further includes a filler 26. The outer face of leakage detection line 241 may be coated with insulation structure 28 while the outer face of leakage detection line 242 is not coated with insulation structure 28 (as shown in fig. 3A and 3B), it being understood that the outer face of leakage detection line 242 may also be coated with insulation structure 28 while the outer face of leakage detection line 241 is not coated with insulation structure 28 (not shown in the figures). The

leakage detecting lines

241 and 242 may be a metal (e.g., copper, aluminum, etc.) braided structure (as shown in fig. 3A and 3D), a wound structure (not shown) formed by at least one metal wire, a metal foil-clad structure (as shown in fig. 3B and 3C), or a combination of any of these structures. The insulating structure 28 may be integrally formed of a plastic material, or may be formed by covering with an insulating paper, cotton, or other material having electrical insulating properties. The

leakage detecting lines

241 and 242 may be formed by coating with a single-sided insulating material (i.e., one side is conductive and the other side is insulating), without a separate insulating structure 28 (as shown in fig. 3C). The leakage detection line 241 is wrapped around at least one power supply line (a current-carrying core line such as the live line (L)21, the neutral line (N)22, etc.), in the fourth embodiment shown in fig. 3D, the leakage detection line 241 may wrap around both the live line 21 and the neutral line 22, the knot edge structure 28 wraps around the leakage detection line 241 and the ground line 23 and the leakage detection line 242 wraps around the knot edge structure 28, it being understood that the leakage detection line 241 or the leakage detection line 242 may wrap around multiple power supply lines (current-carrying core lines) at the same time.

Fig. 4 is a diagram illustrating a power line leakage current detection protection device according to an embodiment of the present invention. The power supply line leakage current detection protection device 10 includes: a switching unit 103 configured to control a 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, wherein 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 is connected in series with the second leakage detection line 104 d. 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 detecting module 104 b.

Fig. 5 is a schematic diagram of an embodiment in accordance with the invention. As shown in fig. 5, the power line leakage current detection protection apparatus further includes a TEST unit 200, the TEST unit 200 includes a resistor R4 (analog leakage current generating element) and a TEST switch TEST, one end a of a leakage detection line 242 in the power line 2 is connected to the control circuit R2, 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, and thus, the TEST switch TEST is coupled to the

leakage detection lines

241 and 242. In addition, the terminal B of the leakage detection line 241 is coupled to the live line L, and the terminal N is coupled to the terminal a of the leakage detection line 242 via the solenoid SOL, the thyristor SCR, and the resistor 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 to the resistor R3. In this embodiment, the L line forms the TEST circuit M by a resistor R4, a TEST switch TEST, a leakage detection line 241, a leakage detection line 242, and resistors R2, R3, a diode D2, and a solenoid SOL to N line.

The TEST switch TEST is normally turned on, and when the

leakage detection lines

241 and 242 normally operate (are not open), or no current leakage occurs between the

power supply lines

21, 22 and 23 and the

leakage detection lines

241 and 242, the SCR is not triggered, and the product normally operates. 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.) forms a current path with the

leakage detection lines

241 and 242, and the leakage detection module is in a state capable of detecting the simulated leakage current). The simulated leakage current enables the voltage of two ends of the resistor R3 to rise, and then the silicon controlled rectifier SCR is driven to be conducted, when the silicon controlled rectifier SCR is conducted, the N line, the solenoid SOL, the silicon controlled rectifier SCR and the diode D1 form a tripping loop through the L line, and larger current is generated on the solenoid SOL to form a large enough magnetic field, so that the RESET switch is tripped, and then a power supply is cut off. If any of the lines or elements in the

leakage detection lines

241 and 242 are open, the TEST circuit M cannot form a closed loop when the TEST switch TEST is closed, no analog 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, the leakage detection module is in a state of failing to detect the analog leakage current), the product will not trip, so as to alert a user that an open circuit condition may exist in at least one of the leakage detection lines 241 and/or the leakage detection lines 242. Accordingly, the user can detect whether the

leakage detecting lines

241 and 242 of the power lines are intact by operating the TEST switch TEST. It will be appreciated that depending on the application, it may be possible to detect whether any of the components of the test circuit are functioning properly.

By implementing the technical scheme of the invention, the detection of the leakage detection line can be realized by manually operating the TEST switch TEST, so that the safety is improved.

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

Claims

1. A power line leakage current detection protection device, comprising:

a switching unit configured to control a power connection between the input terminal and the output terminal; and

a leakage protection unit including 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 are connected in series;

wherein the switch driving module is configured to control the switching unit to disconnect the power connection according to a leakage current signal detected by the leakage detecting module.

2. The power line leakage current detection protection device of claim 1, further comprising a test unit including a test switch coupled to the leakage protection unit and constituting a test circuit by at least the test switch and the leakage protection unit, wherein when the test switch is closed, the switch driving module controls the switch unit to disconnect the power connection if the leakage detection module is in a first state.

3. The power line leakage current detection protection device of claim 2, wherein when said test switch is closed, said switching unit maintains said power connection if said leakage detection module is in a second state.

4. The power line leakage current detection protection device of claim 1, further comprising an insulating structure surrounding at least one of the first leakage detection line and the second leakage detection line.

5. The power line leakage current detection protection device according to claim 4, wherein the insulation structure is integrally formed by rubber plastic material or covered by insulation paper and/or cotton.

6. The power line leakage current detection protection device of claim 4, wherein said first leakage detection line and said second leakage detection line each cover at least one power line of the power lines.

7. The power line leakage current detection protection device of claim 6, wherein said first leakage detection line surrounds a first power supply line and said second leakage detection line surrounds a second power supply line.

8. The power cord leakage current sensing protection device of claim 6, wherein said first leakage detection line surrounds a first power supply line and a second power supply line, said insulating structure surrounds said first leakage detection line and a ground line, and said second leakage detection line surrounds said insulating structure.

9. The power cord leakage current sensing protection device of claim 6, wherein said first leakage sensing line surrounds a first power supply line, a second power supply line and a third power supply line, said insulating structure surrounds said first leakage sensing line and a ground line, and said second leakage sensing line surrounds said insulating structure.

10. The power supply line leakage current detection protection device of claim 1, wherein said first leakage detection line and said second leakage detection line are a metal braided structure or a metal wire wound structure or a combination of a metal braided structure and a metal wire wound structure.

11. The power supply line leakage current detection protection device of claim 1, wherein said first leakage detection line and said second leakage detection line are metal foil clad structures or a combination of metal braided structures and metal foil clad structures.

12. The power supply line leakage current detection protection device of claim 1, wherein one side of the first leakage detection line and/or the second leakage detection line is made of an insulating material, the other side is made of a conductive material, and the insulating material is located at the outer side.