Power supply cable ground fault detection indicating device

Abstract

The utility model discloses a power supply cable ground fault detection indicating device, and relates to the technical field of cable detection. The detection circuit board, the liquid crystal display screen and the touch button module with the lamp are arranged in the shell, a direct-current battery, an inverter, a residual current transformer, a control module and a relay module are arranged on the detection circuit board, the output end of the direct-current battery is electrically connected with the input end of the inverter, and the output end of the inverter is connected with a five-core cable. The five-core cable comprises an A-phase line, a B-phase line, a C-phase line, an N line and a PE line, the A-phase line, the B-phase line, the C-phase line and the N line are sleeved with coils of the residual current transformer, three sets of relays of the relay module are connected to the A-phase line, the B-phase line and the C-phase line respectively, and the residual current transformer and the relay module are both electrically connected with the control module; the cable grounding fault detection device has the advantages that the cost is low, the carrying is convenient, and the automatic and accurate cable grounding fault detection can be realized.

Description

Technical Field

[0001] The present application relates to the field of cable detection technology, and in particular to a power supply cable grounding fault detection and indication device. Background Art

[0002] Cable grounding faults can disrupt the stability of power systems, leading to serious consequences such as equipment damage, power outages, and personal injury. Existing cable grounding fault detection typically uses insulation resistance testing, grounding current detection, or residual current detection. However, residual current detection requires manual replacement of the phase conductor of the detection cable, resulting in a low level of automation. Existing detection devices are also bulky and difficult to carry. Utility Model Content

[0003] In view of this, the present application provides a power supply cable grounding fault detection and indication device to solve the technical problems that the existing grounding fault detection requires manual replacement of the phase line of the detection cable when performing residual current detection, the degree of automation is low, and the existing detection device has the problems of large size and inconvenience in carrying.

[0004] To achieve the above-mentioned object, the present utility model provides the following technical solutions: a power supply cable ground fault detection and indication device, comprising: a housing;

[0005] A detection circuit board is provided in the housing, and a DC battery, an inverter, a residual current transformer, a control module, and a relay module are provided on the detection circuit board. The output end of the DC battery is electrically connected to the input end of the inverter. The output end of the inverter is connected to a five-core cable, which includes an A-phase line, a B-phase line, a C-phase line, an N-line, and a PE line. The coil of the residual current transformer is sleeved on the A-phase line, the B-phase line, the C-phase line, and the N-line. The relay module includes three groups of relays, which are respectively connected to the A-phase line, the B-phase line, and the C-phase line. The residual current transformer and the relay module are both electrically connected to the control module.

[0006] LCD screen;

[0007] The illuminated touch button module, the liquid crystal display screen and the illuminated touch button module are all electrically connected to the control module.

[0008] Furthermore, a wiring hole is provided on the outer shell, and the end of the five-core cable passes through the wiring hole and is connected to one end of the cable to be tested. The N line end and the PE line end at the front end of the five-core cable are connected together. Different types of clips are connected to the end of the five-core cable to adapt to cables of different wire diameters and wiring forms.

[0009] Furthermore, the control module includes a controller chip and a memory chip, and the memory chip is electrically connected to the controller chip.

[0010] Furthermore, it also includes a power switch, which is arranged on the power supply circuit of the device.

[0011] Furthermore, the illuminated touch button module includes an A-phase voltage control button, a B-phase voltage control button, a C-phase voltage control button, a confirmation button, and an automatic detection button.

[0012] It can be seen from the above technical solution that the advantages of the utility model are:

[0013] The present invention has a simple structure, low cost, and is easy to carry. It does not require manual replacement of the detection cable connector and can realize automatic and accurate detection of cable grounding faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings that constitute a part of this application are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0015] Figure 1 The utility model is a structural schematic diagram of a power supply cable grounding fault detection and indication device.

[0016] Figure 2 This is a schematic diagram of the C-phase cable grounding fault wiring of the present invention.

[0017] Figure 3 This is the wiring diagram of the N-phase cable grounding fault of the utility model.

[0018] Reference numerals:

[0019] Housing-1, LCD display-2, illuminated touch button-3. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail in conjunction with the embodiments and drawings. Here, the illustrative embodiments of this application and their descriptions are used to explain this application, but are not intended to limit this application.

[0021] This application provides a power supply cable ground fault detection and indication device, which is used to find the ground fault point of the power supply cable and can automatically determine the ground fault phase of the cable. Figures 1 to 2The device includes a housing 1; a detection circuit board disposed within the housing 1; and a liquid crystal display 2 and illuminated touch button 3 modules disposed on the housing 1. The detection circuit board is equipped with a DC battery, an inverter, a residual current transformer, a control module, and a relay module. The output of the DC battery is electrically connected to the input of the inverter. The output of the inverter is connected to a five-core cable comprising phases A, B, C, N, and PE. The coil of the residual current transformer is mounted on the phases A, B, C, and N. The relay module includes three sets of relays, each connected to the phases A, B, and C. The residual current transformer and relay module are both electrically connected to the control module. The LCD 2 and illuminated touch button 3 modules are both electrically connected to the control module. The housing 1 is provided with a wiring hole, through which the end of the five-core cable passes and connects to one end of the cable under test. The N and PE wires are connected together at the front end of the five-core cable. The end of the five-core cable is connected with different types of clips to accommodate cables of different wire diameters and wiring arrangements. The control module includes a controller chip and a memory chip, which is electrically connected to the controller chip.

[0022] The present application also includes a power switch, which is set on the power supply circuit of the device to control the on and off of the power supply. The lighted touch button 3 module includes an A-phase voltage control button, a B-phase voltage control button, a C-phase voltage control button, a confirmation button, and an automatic detection button.

[0023] like Figure 2 As shown, in this embodiment, the ends of the five-core cable include A, B, C, N, and PE. When performing ground fault detection, they are respectively connected to the A, B, C, N, and PE lines of the line cable to be tested. The N and PE ends of the front end of the five-core cable are connected together. During detection, the fault is first confirmed, and then the A-phase voltage control button is pressed. The controller controls the corresponding relay to turn on, and applies a 36V AC safety voltage between the A-phase cable and the N-phase cable that have been disconnected from the power supply. The A-phase voltage value is displayed on the LCD 2. The PE end of the device is connected to the PE line of the outgoing cable and to the ground terminal of the distribution cabinet (if the cable does not have a PE line, it is directly connected to the ground terminal of the distribution cabinet). Figure 2As shown. The device incorporates a residual current transformer to detect residual current variations. Pressing the confirm button stores the measured data in memory and displays the residual current value on the display. Using the same method, a 36V AC voltage is applied between cables BN and CN (applying voltage between only one phase and the N phase at a time). The residual current in cables ABCN is measured. Based on the residual current values, the ground fault in the phase with the highest residual current value can be determined. If the residual current values ​​measured for all three phases are similar, the ground fault in phase N is determined. For example, if phase C is grounded, the residual current in cables ABCN measured with 36V AC applied to CN (PE) will be significantly higher than that measured with voltage applied to AN (PE) or BN (PE). The device displays the test results on the LCD screen. Since the device output is already connected to each cable phase via thin cables, pressing the illuminated touch button (auto) automatically completes the above operation and displays the test results, achieving automatic detection without the need to manually change the test phase.

[0024] After determining which phase of the cable has a ground fault, you can continuously apply a 36V voltage to the phase cable, use the dichotomy method or untie the cable joints before and after the suspected cable ground fault point, and measure the residual current values ​​of cables ABCN at the same time. Based on whether the residual current value changes suddenly when the fault phase cable head is untied, you can determine which section of the cable has a ground fault. Figure 2As shown in the figure, consider a ground fault in phase C of a streetlight cable. If a ground fault occurs in phase C, a 36V AC voltage is applied between phases C and N, while measuring the residual current in cables ABCN. When cable head 1 of phase C is untied, the measured residual current decreases significantly, indicating the ground fault has been resolved. Therefore, the cable ground fault is determined to be behind cable head 1. When cable head 3 of phase C is untied, the measured residual current does not change significantly, indicating the ground fault has not been resolved. Therefore, the cable ground fault is determined to be ahead of cable head 3. Continuing to untie cable head 2 toward cable head 1, the measured residual current does not change significantly, indicating the ground fault is ahead of cable head 2. Since there are no more cable heads to untie between cable heads 1 and 2, the ground fault in phase C is determined to be between segments 1 and 2. The above method can also be used to locate the ground fault points in phases A and B. Although phases A, B, and C are connected together through a load, the residual current values ​​of each phase will affect each other. Each phase in the line may have multiple points of poor insulation to ground. However, by removing the cable connectors and comparing the difference in residual current values ​​between ABCN before and after removal, we can identify the section with the largest change in residual current value, thereby confirming the location of the most severe ground fault in the cable. Absolute accuracy of residual current measurements at every point in the line cable is not required, as this avoids influencing factors. If multiple ground fault points exist, they can be eliminated one by one based on the points where the residual current value changes.

[0025] like Figure 3 As shown, if the residual current values ​​measured in the three phases are similar, it is determined that a ground fault has occurred in the N-phase cable. When detecting a ground fault in the N-phase cable, swap the output end of the 36V power supply with the previous connection method. For example, the C-phase of the cable (any live wire can be selected) is connected to the N-phase end of the device through a thin cable, the PE end of the device is still connected to the PE line of the cable, and the N-phase of the cable is connected to the C-phase end of the device through a thin cable. In this way, there is a higher voltage on the N-phase cable, and the residual current value of the measured cable will be relatively high, which helps to determine in which section the ground fault point of the N-phase cable is.

[0026] During testing, regardless of which two phases a 36V voltage is applied, the residual current values ​​of cables ABCN are measured each time. The phase with the largest value is identified as the faulty phase. The specific location of the fault point is determined by the sudden change in the residual current value when the faulty phase cable head is uncoupled. This device can be widely used to locate grounding faults in cables in various fields, such as street lighting circuits and power supply lines.

[0027] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art will appreciate that various modifications and variations of the present embodiment are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A power supply cable grounding fault detection and indication device, characterized in that: include: Housing (1); A detection circuit board is arranged in the housing (1), the detection circuit board is provided with a DC battery, an inverter, a residual current transformer, a control module and a relay module, the output end of the DC battery is electrically connected to the input end of the inverter, the output end of the inverter is connected to a five-core cable, the five-core cable includes an A-phase line, a B-phase line, a C-phase line, an N-line and a PE line, the coil of the residual current transformer is sleeved on the A-phase line, the B-phase line, the C-phase line and the N-line, the relay module includes three groups of relays, the three groups of relays are respectively connected to the A-phase line, the B-phase line and the C-phase line, and the residual current transformer and the relay module are both electrically connected to the control module; LCD screen (2); A touch button module (3) with light, the liquid crystal display (2) and the touch button module (3) with light are both electrically connected to the control module.

2. The power supply cable grounding fault detection and indication device according to claim 1, characterized in that: The housing (1) is provided with a wiring hole, the end of the five-core cable passes through the wiring hole and is connected to one end of the cable to be tested, the N line end and the PE line end at the front end of the five-core cable are connected together, and the end of the five-core cable is connected with clips of different models to adapt to cables of different wire diameters and wiring forms.

3. The power supply cable grounding fault detection and indication device according to claim 1, characterized in that: The control module includes a controller chip and a memory chip, and the memory chip is electrically connected to the controller chip.

4. The power supply cable grounding fault detection and indication device according to claim 1, characterized in that: The device also includes a power switch, which is arranged on the power supply circuit of the device.

5. The power supply cable grounding fault detection and indication device according to claim 1, characterized in that: The illuminated touch button module (3) comprises an A-phase voltage control button, a B-phase voltage control button, a C-phase voltage control button, a confirmation button, and an automatic detection button.

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