Cable grounding fault troubleshooting device

Abstract

The utility model discloses a cable grounding fault troubleshooting device, and relates to the technical field of cable detection devices, the cable grounding fault troubleshooting device comprises an adjustable electric transducer, a variable resistance box and a clip-on ammeter, the variable resistance box is connected in series with the output end of the adjustable electric transducer, and the output voltage of the adjustable electric transducer is 0V-36V; compared with the prior art, the device is simple in structure and convenient to use, fault points can be quickly found, and the safety of maintenance personnel and equipment can be ensured by adopting the adjustable transformer with the output voltage of 0V-36V.

Description

Technical Field

[0001] This utility model relates to the technical field of cable testing devices, and in particular to a cable grounding fault diagnosis device. Background Technology

[0002] As the carrier of electrical energy in factories, the safety of cables is of paramount importance. However, due to the harsh laying environment, cables are easily damaged or prone to grounding faults due to insulation aging. The grounding fault rate increases with operating time. Since cables are generally buried underground or in cable trenches, locating a grounding fault is relatively difficult, often taking hours or even days. This not only wastes significant manpower and resources but also causes incalculable power outage losses.

[0003] For example, a grounding fault occurred in the power supply cable of the purifier in Unit 4 of the Liuzhou Iron & Steel Gas Company's oxygen generator, causing the unit to shut down. Unit 4 has four purifiers, each with four sets of heating elements, each with a power output of 270kW. Each set is powered by two parallel cables of specification YJV-0.6 / 1KV 3*150+1*80, totaling 32 low-voltage cables. The total length of the power supply cable for the purifier electric heaters is 500m. 450m of the cable runs along an underground cable trench from the power distribution room to the site, covered with a cement slab. Another 50m runs along a 5-meter-high cable tray on site. Due to design limitations, the cable trench is congested and has limited space. Maintenance personnel have tried various methods, including DC bridge measuring instruments and manual troubleshooting, but have been unable to locate the fault. Therefore, it is necessary to develop a cable grounding fault troubleshooting device for rapid fault detection. Utility Model Content

[0004] The purpose of this invention is to provide a cable grounding fault investigation device, which can solve the problem of difficulty in locating the grounding fault point in existing cable grounding faults.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows: This cable grounding fault investigation device includes an adjustable transformer, a variable resistor box and a clamp meter. The variable resistor box is connected in series with the output terminal of the adjustable transformer, and the output voltage of the adjustable transformer is 0V-36V.

[0006] In the above-mentioned technical solution for the cable grounding fault investigation device, a more specific technical solution could be: the resistance range of the variable resistor box is 0Ω-72Ω.

[0007] In some possible implementations, the variable resistance box uses a heat-resistant resistance wire with a temperature tolerance of ≥200°C.

[0008] In some possible implementations, the adjustable transformer is a JMB-300 adjustable transformer.

[0009] In some possible implementations, the variable resistance box is a variable resistance box of model ZX25a.

[0010] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art:

[0011] 1. This device has a simple structure and is easy to use. It can quickly locate fault points and uses an adjustable transformer with an output voltage of 0V-36V to ensure the safety of maintenance personnel and equipment.

[0012] 2. For low-voltage cables laid in cable trenches, it is not necessary to open all the cable trench covers. Only a few points need to be opened for testing, which can reduce a lot of manpower and material resources and improve work efficiency. It is suitable for situations where there are many cables in the cable trench and it is difficult to find the grounding fault point. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the principle of this utility model.

[0014] Explanation of markings in the diagram:

[0015] Adjustable transformer 1, variable resistance box 2, clamp ammeter 3. Detailed Implementation

[0016] To make the above-mentioned objectives, features, and advantages of this utility model more readily understood, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model; however, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0017] In the description of this utility model, it should be understood that the terms "middle", "length", "width", "upper", "lower", "front", "rear", "top", "bottom", "inner", "outer", "radial", "circumferential", etc., indicate the orientation or positional relationship given in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the indicated position or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0018] like Figure 1The cable grounding fault diagnosis device shown includes an adjustable transformer 1, a variable resistor box 2, and a clamp meter 3. The adjustable transformer 1 and the variable resistor box 2 are connected in series. The variable resistor box 2 is connected to the output terminal of the adjustable transformer 1. The output voltage of the adjustable transformer 1 is 0V-36V. The resistance of the variable resistor box 2 is variable in the range of 0Ω-72Ω. The variable resistor box 2 uses heat-resistant resistance wire with a temperature resistance ≥200℃ and its resistance value is not affected by temperature changes to ensure stable output current. The adjustable transformer can be a JMB-300 model, and the variable resistor box can be a ZX25a model.

[0019] When a cable grounding fault occurs, connect the L end of this device to the cable with the grounding fault, and the E end to the grounding terminal that is effectively connected to the earth. This forms a closed current loop consisting of the adjustable transformer, the variable resistor box, the faulty cable, and the earth. Adjust the device's output voltage to 12V and its resistance to 12Ω, then turn on the device's power. A current of 1A will flow in the loop. Use a clamp meter to test the faulty cable. If the current measured at point A is 1A, the fault point C is after the measured point. If the current measured at point B is 0A, the fault point C is between the measured point and the power supply, allowing for quick location of the fault.

[0020] When it is inconvenient to continuously measure cables in cable trenches, the bisection method can be used. Set a measurement point at 1 / 2 of the total cable length, use a clamp meter to measure the current, and use the same method as above to determine whether the fault point is in the first 1 / 2 or the second 1 / 2 of the cable length. Then, continue to search in this way until the fault point is finally determined.

[0021] A grounding fault occurred in the power supply cable of the purifier of the No. 4 oxygen generator at Liugang Gas Company. After taking safety precautions, the maintenance electrician used this troubleshooting device to dig up the cement slab of the cable trench at approximately 250 meters (halfway through the total length of the faulty cable) and measure the current in the cable. No 1A injection current was detected, thus determining that the grounding point was within 250 meters of the distribution cabinet. The same method was used to search the preceding 250 meters, and the grounding point of the faulty cable was finally found approximately 100 meters from the distribution cabinet, quickly locating the fault.

Claims

1. A cable grounding fault diagnosis device, characterized in that: It includes an adjustable transformer (1), a variable resistor box (2) and a clamp meter (3). The variable resistor box (2) is connected in series with the output terminal of the adjustable transformer (1). The output voltage of the adjustable transformer (1) is 0V-36V.

2. The cable grounding fault investigation device according to claim 1, characterized in that: The variable resistance box (2) has a resistance range of 0Ω-72Ω.

3. The cable grounding fault investigation device according to claim 1 or 2, characterized in that: The variable resistance box (2) uses heat-resistant resistance wire, which can withstand temperatures ≥200℃.

4. The cable grounding fault investigation device according to claim 3, characterized in that: The adjustable transformer (1) is an adjustable transformer of model JMB-300.

5. The cable grounding fault investigation device according to claim 4, characterized in that: The variable resistance box (2) is a variable resistance box of model ZX25a.

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