A device and method for detecting leakage current in low-voltage lines under load

Abstract

This invention discloses a device and method for detecting leakage current in low-voltage lines under load. The device includes a clamp-on ammeter and a leakage current detection circuit. The leakage current detection circuit includes a first clamp, a second clamp, a current-limiting element, a rectifier module, and a third clamp. The first and second clamps are connected by a wire. The current-limiting element and the rectifier module are connected in series on the wire connecting the first and third clamps. The rectifier module is configured to allow unidirectional current flow from the first clamp to the third clamp. This invention can quickly and accurately diagnose the location of leakage current, greatly improving the rapid response of leakage current maintenance in transmission lines. This invention is portable, simple to operate, and the components are inexpensive and reusable, reducing operating costs. This invention does not require disassembling the transformer, reducing the labor intensity of the inspection process. It can locate leakage current without power interruption, and the inspection process will not affect the power supply to residents and businesses, making it easy to promote and apply.

Description

Technical Field

[0001] This invention relates to the field of power transmission, and in particular to a simple-to-operate device and method for quickly checking for leakage current in low-voltage lines under load. Background Technology

[0002] In existing power transmission lines, during the process of transmitting power to users through transformer transmission lines (below 0.4KV), leakage may sometimes occur, which requires power technicians to investigate and maintain the lines.

[0003] Currently, commonly used methods for detecting electrical leakage are as follows: Figure 1 As shown, before checking for leakage, all four outgoing wires (A, B, C, and N) of the main switch in the distribution box must first be disconnected. Then, connect the four wires together, and connect any phase wire from any jumper at the front end of the switch to the three phase wires that were previously disconnected, so that the leakage line forms a loop through the earth and the grounding flat iron of the transformer. Next, use the AC current setting of a clamp meter to test the connected A, B, and C phase wires, and then check each phase step by step until the leakage point is found. After finding and repairing the leakage, restore power.

[0004] This method has the following problems: technicians need to disconnect each phase wire at the output end of the main switch of the distribution box, and at the same time, they need to check the three phase wires A, B and C step by step, which is a lot of work and unsafe; in particular, during the inspection process, it is necessary to cut off the power to residents or factories in the leakage area, which causes great inconvenience to residents' lives and factories' production power use. Summary of the Invention

[0005] The purpose of this invention is to provide a reusable low-voltage line overload leakage detection device and method that is simple to operate, can quickly detect leakage locations in power transmission lines, and can be used multiple times.

[0006] To achieve the above objectives, the present invention first discloses a low-voltage line under load leakage current detection device, including a clamp-on ammeter and a leakage current detection circuit. The leakage current detection circuit includes a first clamp, a second clamp, a current limiting element, a rectifier module, and a third clamp. The first clamp and the second clamp are connected by a wire. The current limiting element and the rectifier module are connected in series on the wire connecting the first clamp and the third clamp. The rectifier module is configured to allow current to flow unidirectionally from the first clamp to the third clamp.

[0007] Furthermore, the first, second, and third electrical clamps are all alligator clips.

[0008] Furthermore, the conductor is 800-1200mm long and has a cross-sectional area of ​​4-6mm². 2 Soft copper wire.

[0009] Furthermore, the current-limiting element is a light bulb with a power of 150-200W.

[0010] Furthermore, the rectifier module is a rectifier diode, and the rectifier diode is model 1N5408.

[0011] Furthermore, the clamp meter is a manual range AC / DC clamp meter.

[0012] Then, this invention discloses a method for detecting leakage current in low-voltage lines under load, including the low-voltage line leakage current detection device described in the above scheme, comprising the following steps:

[0013] S1, use the first clamp to clamp the transformer's grounding wire, with the clamp positioned at the upper end of the screw between the N-phase line and the grounding flat iron;

[0014] S2, use the second clamp to clamp the grounding flat iron of the transformer;

[0015] S3, Remove the screws at the grounding flat iron to separate the grounding flat iron from the transformer's grounding wire;

[0016] S4, use the third clamp to clamp the transformer's grounding flat iron, and release the second clamp;

[0017] S5. Use the DC current setting of a clamp meter to test the A, B, and C phase lines at the transformer output. If the clamp meter shows current, continue the investigation until the leakage point is reached.

[0018] Furthermore, in step S3, when removing the screws at the grounding flat iron, wear insulating gloves.

[0019] Furthermore, in step S4, after releasing the second electrical clamp, the second electrical clamp is connected to the first electrical clamp.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] 1. This invention can quickly and accurately diagnose the location of leakage current, greatly improving the rapid response of leakage current maintenance of transmission lines;

[0022] 2. This invention is easy to carry, simple to operate, and the components of the device are inexpensive and can be reused multiple times, which also reduces the cost of use.

[0023] 3. This invention does not require disassembling the transformer, reducing the labor intensity of the troubleshooting process. It can locate the leakage point without interrupting power supply, and the troubleshooting process will not affect the electricity use of residents and businesses, making it easy to promote and apply.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a publicly available schematic diagram of a low-voltage line under load for leak detection;

[0027] Figure 2 This is a schematic diagram of the clamp-on leakage current testing device of the low-voltage line under load leakage current detection device and method disclosed in the preferred embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the low-voltage line overload leakage detection device disclosed in the preferred embodiment of the present invention;

[0029] Figure 4 This is a flowchart illustrating the method for detecting leakage current in low-voltage lines under load, as disclosed in a preferred embodiment of the present invention.

[0030] Legend:

[0031] 1. First electrical clamp; 2. Second electrical clamp; 3. Third electrical clamp; 4. Light bulb; 5. Rectifier diode; 6. Transformer; 7. Clamp-on ammeter; 8. Grounding flat iron; 9. Leakage current; 10. Screw. Detailed Implementation

[0032] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0033] This invention first discloses a low-voltage line overload leakage detection device, such as... Figure 2 As shown, the device includes a clamp-on ammeter 7 and a leakage current detection circuit. The leakage current detection circuit includes a first clamp 1, a second clamp 2, a current-limiting element, a rectifier module, and a third clamp 3. The first clamp 1 and the second clamp 2 are connected by a wire. A current-limiting element and a rectifier module are connected in series on the wire connecting the first clamp 1 and the third clamp 3. The rectifier module is configured to allow unidirectional current flow from the first clamp 1 to the third clamp 3. The wire is 1000mm long and has a cross-sectional area of ​​6mm². 2 The device uses soft copper wire. It allows for single-person operation and troubleshooting without disassembling transformers or distribution boxes, reducing labor intensity. More importantly, it can locate leaks without power interruption, ensuring no disruption to residential or business electricity use, thus facilitating widespread application.

[0034] In this embodiment, the first electrical clamp 1, the second electrical clamp 2, and the third electrical clamp 3 are all alligator clips that can withstand large currents. Once they are clamped and connected, the hands can be freed to check for leakage.

[0035] In this embodiment, the current limiting element is bulb 4, which is 200W. Compared with other high-resistance current limiting components, the cost of use is significantly lower. The rectifier module directly uses rectifier diode 5, which is model 1N5408. Similarly, compared with other types of rectifier circuit modules, the cost of use is significantly reduced, making it easier to promote and apply.

[0036] In this embodiment, the clamp meter 7 is a manual range AC / DC clamp meter, specifically the Binjiang brand BM823 model manual range AC / DC clamp meter. An automatic range clamp meter is not used because it can prevent the automatic range clamp meter from automatically switching to the AC current range during measurement, thus making it unable to measure or causing measurement failure.

[0037] Then, this invention discloses a method for detecting leakage current in low-voltage lines under load. This method should be operated outside of periods of thunderstorms, such as... Figure 3 and 4 As shown, the low-voltage line overload leakage detection device, including the above scheme, includes the following steps:

[0038] S1, use the first electrical clamp 1 to clamp the grounding wire of the transformer 6, specifically at the upper end of the screw 10 of the grounding flat iron 8 from the N phase line;

[0039] S2, use the second energizing clamp 2 to clamp the grounding flat iron 8 of the transformer 6, thereby short-circuiting the grounding line of the transformer 6 between the second energizing clamp 2 and the first energizing clamp 1, ensuring that the transformer 6 remains in a safe grounded state when the screw 10 at the grounding flat iron 8 is removed;

[0040] S3, remove the screw 10 at the grounding flat iron 8 to separate the grounding flat iron 8 from the grounding wire of the transformer 6. At this time, the transformer 6 is grounded through the first electrical clamp 1, the second electrical clamp 2 and the wires between them.

[0041] S4, clamp the grounding flat iron 8 of transformer 6 with the third electrical clamp 3, and release the second electrical clamp 2, so that transformer 6 forms a DC conductive circuit with the leakage point after being grounded through light bulb 4 and rectifier diode 5.

[0042] S5. Use the DC current setting of clamp meter 7 to test the A, B and C phase lines at the output of transformer 6. If clamp meter 7 shows a current, then there is a leakage current in that phase line (the leakage detection line and the leakage location form a leakage current 9 through the ground). This allows you to quickly identify the phase line with the leakage. Then, continue checking until you reach the leakage point. This makes it easy and quick to find the leakage location. After checking, reinstall the screws 10 of the grounding flat iron 8.

[0043] In this embodiment, after removing the screw 10 at the grounding flat iron 8 in step S3, insulated gloves are put on to prevent the transformer 6 from leaking current and causing electric shock to the technician.

[0044] In this embodiment, in step S4, after releasing the second electrical clamp 2, the second electrical clamp 2 is connected to the first electrical clamp 1, thereby short-circuiting the wire between the second electrical clamp 2 and the first electrical clamp 1.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting leakage current in low-voltage lines under load, comprising a device for detecting leakage current in low-voltage lines under load, characterized in that, The low-voltage line under load leakage detection device includes a clamp ammeter (7) and a leakage detection circuit. The leakage detection circuit includes a first clamp (1), a second clamp (2), a current limiting element, a rectifier module, and a third clamp (3). The first clamp (1) and the second clamp (2) are connected by a wire. The current limiting element and the rectifier module are connected in series on the wire connecting the first clamp (1) and the third clamp (3). The rectifier module is configured to allow current to flow unidirectionally from the first clamp (1) to the third clamp (3). The current limiting element is a light bulb (4). The rectifier module is a rectifier diode (5). The steps include: S1, clamping the grounding wire of the transformer (6) with the first clamp (1), with the clamping position located at the upper end of the screw (10) from the N phase line to the grounding flat iron (8); S2, clamping the grounding flat iron (8) of the transformer (6) with the second clamp (2); S3, removing the screw (10) at the grounding flat iron (8) to separate the grounding flat iron (8) from the grounding wire of the transformer (6); S4, clamping the grounding flat iron (8) of the transformer (6) with the third clamp (3), and loosening the second clamp (2); S5, using the DC current range of the clamp ammeter (7) to test the A, B and C phase lines at the output terminal of the transformer (6). If the clamp ammeter (7) shows a current, then continue to check until the leakage point.

2. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, In step S3, when removing the screw (10) at the grounding flat iron (8), wear insulating gloves.

3. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, In step S4, after releasing the second electrical clamp (2), the second electrical clamp (2) is connected to the first electrical clamp (1).

4. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, The first electrical clamp (1), the second electrical clamp (2), and the third electrical clamp (3) are all alligator clips.

5. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, The conductor is 800-1200mm long and has a cross-sectional area of ​​4-6mm². 2 Soft copper wire.

6. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, The power of the bulb (4) is 150-200W.

7. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, The rectifier diode (5) is model 1N5408.

8. The method for detecting leakage current in low-voltage lines under load according to claim 1, characterized in that, The clamp meter (7) is a manual range AC / DC clamp meter.

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