Joint fault detection device

Abstract

The utility model provides a joint fault detection device, and belongs to the technical field of electric power engineering. The device comprises a mutual inductor, a cable fault locator and an alarm device, the mutual inductor is installed at the position of a cable joint, the mutual inductor is electrically connected with the alarm device and the cable fault locator, and a secondary side loop is always closed when the mutual inductor works. According to the utility model, the mutual inductor is installed at the cable joint, sound-light alarm is carried out when the mutual inductor monitors that the current is abnormal, and then an inspector uses the cable fault locator to locate the specific position of the fault. Compared with the prior art, the cable fault detection device is reasonable in structure and simple to operate, high cost of fault detection is reduced, and long-time power failure which is difficult to avoid when the cable fault is difficult to find can be reduced. According to the utility model, the cable current can be detected in real time and the fault position can be timely and accurately positioned. And long-time power failure during cable fault and high cost caused by long-time power failure are avoided.

Description

Technical Field

[0001] This utility model relates to the field of power engineering technology, specifically a joint fault detection device. Background Technology

[0002] With the continuous development of society and the economy, the demand for electricity is increasing, which has led the country and society to attach greater importance to the safety of the power grid and to raise the requirements for it. As the main unit for transmitting electrical energy, power cables play a vital role in the safe operation of the power grid. Over time, the scale of distribution network cables has become larger and larger, and the cables put into operation in the early stage are gradually entering the aging stage. Faults such as dendritic aging of cable insulation and edge discharge due to moisture ingress of cable accessories caused by the breathing effect are becoming more common.

[0003] Because cables are buried underground, faults are difficult to locate. Inaccurate fault location or unclear fault paths further complicate the search, wasting considerable time and potentially causing serious injury and loss. Therefore, accurate cable fault detection is of paramount importance for both social production and personal safety.

[0004] Existing partial discharge monitoring sensors mostly use high-frequency current sensors to monitor partial discharge signals. Due to their large size, high-frequency current sensors cannot be installed inside the copper protective shell of the cable joint and can only be installed on the grounding wire outside the copper protective shell of the cable joint. External sensors are exposed to the external environment and are therefore easily damaged by moisture. External sensors are far from the cable core, resulting in weak partial discharge signals. Moreover, the sensors not only capture internal signals but also external interference, and the external interference signals are often much stronger than the internal partial discharge signals, thus failing to accurately and effectively monitor partial discharge in cables. Summary of the Invention

[0005] The technical problem to be solved by this utility model is: how to realize real-time detection of cable current and timely and accurate location of fault.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] A joint fault detection device includes a current transformer, a cable fault locator, and an alarm device. The current transformer is installed at the cable joint location and is electrically connected to both the alarm device and the cable fault locator. The secondary circuit of the current transformer is always closed during operation.

[0008] Preferably, the alarm device is an audible and visual alarm device.

[0009] Preferably, the device also includes a solar power supply module, which is electrically connected to the current transformer.

[0010] Preferably, the cable fault locator can detect high-resistance flashover faults, high and low resistance grounding, short circuits, cable breaks, and poor contact.

[0011] Preferably, the cable fault locator is equipped with an acoustic locator.

[0012] Preferably, the primary coil of the current transformer is connected in series in the circuit, and the number of turns is less than a certain threshold.

[0013] Preferably, the current coil impedance of the instruments and relays connected to the secondary coil of the current transformer is less than a certain threshold.

[0014] Preferably, the current transformer is electrically connected to the alarm device and the cable fault locator in sequence through a current terminal, a current converter, and a boost module.

[0015] Preferably, the current transformer is installed at the cable joint, and the cable fault locator is electrically connected to the current transformer via a sampler.

[0016] Preferably, the current transformer includes an iron core, a primary winding, a secondary winding, and a load, wherein the primary winding and the secondary winding are respectively disposed on both sides of the iron core, the primary winding is connected in series between the power source and the load, and the secondary winding is connected to the load.

[0017] In the above technical solutions, the secondary circuit of the current transformer is always closed during operation. Therefore, the impedance of the series coil of the measuring instrument and the protection circuit is very small, and the operating state of the current transformer is close to a short circuit. The current transformer converts the large primary current into a small secondary current for measurement; the secondary side must not be open-circuited. The cable fault locator tests for high-resistance flashover faults, high and low resistance grounding, short circuits, cable breaks, poor contacts, and other faults in cables. The cable fault locator is equipped with an acoustic fault location instrument, which can be used to accurately determine the precise location of the fault point.

[0018] This invention provides a cable joint fault detection device. The solution involves installing a current transformer at the cable joint. When the current transformer detects an abnormal current, it triggers an audible and visual alarm. Then, inspection personnel use a cable fault locator to pinpoint the exact location of the fault.

[0019] The innovative aspects of this utility model are mainly reflected in the following aspects:

[0020] Innovation Point 1: The primary coil of the current transformer is connected in series in the circuit and has very few turns. Therefore, the current in the primary coil depends entirely on the load current of the circuit being tested and is independent of the secondary current.

[0021] Innovation Point 2: The current coil impedance of the instruments and relays connected to the secondary coil of the current transformer is very small, so under normal circumstances, the current transformer operates in a near-short-circuit state.

[0022] Innovation Point 3: It can reduce the high cost of fault detection and reduce the unavoidable long power outages when arduously searching for cable faults, bringing a lot of convenience to troubleshooting.

[0023] Innovation Point 4: It can isolate high-voltage systems to ensure the safety of people and equipment.

[0024] Compared with existing technologies, this invention has a reasonable structure and simple operation, reducing the high cost of fault detection and minimizing the prolonged power outages that are unavoidable when painstakingly searching for cable faults, thus providing greater convenience for troubleshooting. This invention can detect cable current in real time and accurately locate the fault position, avoiding prolonged power outages and the resulting high costs associated with cable faults. Attached Figure Description

[0025] Figure 1 This is a structural diagram of the present invention;

[0026] Figure 2 This is a structural diagram of the current transformer in this utility model;

[0027] Figure 3 These are on-site photos of this utility model during its application;

[0028] Figure 4 This is a photograph of the current transformer at its installation location in this utility model.

[0029] In the picture:

[0030] Detailed Implementation

[0031] The specific embodiments of this utility model will be described in detail below. To avoid excessive and unnecessary details, well-known structures or functions will not be described in detail in the following embodiments. The approximate language used in the following embodiments can be used for quantitative descriptions, indicating that a certain degree of variation in quantity is permissible without changing the basic function. Unless otherwise defined, the technical and scientific terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art to which this utility model pertains.

[0032] A cable joint fault detection device includes a current transformer, a cable fault locator, and an alarm device. The current transformer is installed at the cable joint location and is electrically connected to both the alarm device and the cable fault locator. The secondary circuit of the current transformer is always closed during operation. The alarm device is an audible and visual alarm. A solar power module is also included, electrically connected to the current transformer. The cable fault locator detects high-resistance flashover faults, high- and low-resistance grounding faults, short circuits, cable breaks, and poor contact. The cable fault locator is equipped with an acoustic locator. The primary coil of the current transformer is connected in series in the circuit, and the number of turns is less than a certain threshold. The impedance of the current coils of the instruments and relays connected to the secondary coil of the current transformer is less than a certain threshold. The current transformer is electrically connected to the alarm device and the cable fault locator sequentially through current terminals, a current converter, and a boost module. Figure 1 As shown, the current transformer is installed at the joint 2 of cable 1, and the cable fault locator 4 is electrically connected to the current transformer via the sampler 3. Figure 2 As shown, the current transformer includes an iron core 5, a primary winding 6, a secondary winding 7, and a load 8. The primary winding 6 and the secondary winding 7 are respectively disposed on both sides of the iron core 5. The primary winding 6 is connected in series between the power supply and the load, and the secondary winding 7 is connected to the load 8.

[0033] The embodiments of this utility model have been described in detail above, but the content described is only a preferred embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, and improvements made within the scope of this utility model application should be included within the protection scope of this utility model.

Claims

1. A joint failure detection device characterized by, The cable fault positioning device comprises a mutual inductor, a cable fault positioning instrument and an alarm device, wherein the mutual inductor is installed at a cable joint position, and the mutual inductor is electrically connected with the alarm device and the cable fault positioning instrument respectively, and the secondary side circuit of the mutual inductor is always closed during operation.

2. The joint failure detection apparatus according to claim 1, characterized by, The alarm device is an audible and light alarm device.

3. The joint failure detection apparatus according to claim 1, characterized by, The device further comprises a solar power supply module which is electrically connected with the mutual inductor.

4. The joint failure detection apparatus according to claim 1, characterized by The detection objects of the cable fault positioning instrument include high resistance flashover fault, high and low resistance grounding, short circuit and cable disconnection, and poor contact.

5. The joint failure detection apparatus according to claim 1, characterized by, The cable fault positioning instrument is provided with an acoustic method fixed-point instrument.

6. The joint fault detection apparatus of claim 1, wherein The primary coil of the mutual inductor is connected in series in a circuit, and the number of turns is less than a certain threshold value.

7. The joint failure detection apparatus according to claim 1, characterized by The impedance of the current coil of the instrument and relay connected with the secondary coil of the mutual inductor is less than a certain threshold value.

8. The joint failure detection apparatus according to claim 1, characterized by The mutual inductor is electrically connected with the alarm device and the cable fault positioning instrument through a current terminal, a current converter and a voltage boosting module in sequence.

9. The joint failure detection apparatus according to claim 1, characterized by The mutual inductor is installed at a joint position of a cable (1), and the cable fault positioning instrument (4) is electrically connected with the mutual inductor through a sampler (3).

10. The joint fault detection apparatus of claim 1, wherein The mutual inductor comprises a core (5), a primary winding (6) and a secondary winding (7), and a load (8), wherein the primary winding (6) and the secondary winding (7) are arranged on the two sides of the core (5) respectively, the primary winding (6) is connected in series between a power supply and a load, and the secondary winding (7) is connected with the load (8).

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