Method for detecting and positioning fault of large-current loop of temporarily-arranged color board room on construction site

Abstract

The invention provides a method for detecting and positioning a large-current loop fault of a temporarily-arranged color board room on a construction site, and the method comprises the following steps: determining a fault type: determining the fault type, and carrying out the preprocessing; a range delimiting step of determining a laying path of a fault line and delimiting a scanning range of a fault area; a preliminary determination step: scanning the line in the scanning range, and preliminarily determining a fault position; and a determination step: detecting the fault position and determining a fault point. According to the method, through preprocessing, preliminary determination through scanning and final determination through detection, rapid and accurate identification of fault points can be realized, manual line disassembly is not needed, the detection time is saved, the troubleshooting efficiency is improved, and the operation safety can be ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical engineering safety detection, in particular to a method for detecting and positioning a large-current loop fault of a temporary color plate house in a construction site. BACKGROUND

[0002] The temporary color plate house in the construction site is widely used in the scenarios of accommodation, office and temporary storage of construction personnel due to its convenience and low cost. The lighting and socket lines of the color plate house are mostly laid along the metal frame, and are affected by the vibration of the construction environment, the interference of personnel activities, the change of outdoor temperature difference and the like. The insulation layer of the line is easy to be damaged by friction with the metal frame, or a large-current loop fault (such as an incomplete short circuit or a short circuit to ground) is caused due to non-standard joint processing, water aging and the like. The core feature of such a fault is that a large-current loop is formed at the fault point, the contact resistance continuously generates heat, the temperature stably rises, but it does not reach the degree of instantaneous metallic short circuit. For this fault, the traditional detection method is: 1. Relies on the experience of electricians to disassemble the line segment by segment, which is time-consuming and laborious, and is easy to miss hidden fault points (such as the line in the color plate sandwich layer), and the troubleshooting efficiency is low; 2. Only measures the insulation resistance or continuity by using a megohmmeter and a multimeter, and multiple segment tests are needed to narrow down the fault range, which cannot quickly locate the fault. SUMMARY

[0003] In view of this, the present application provides a method for detecting and positioning a large-current loop fault of a temporary color plate house in a construction site, aiming at solving the problems of low troubleshooting efficiency and inability to quickly locate the fault in the prior art.

[0004] The present application provides a method for detecting and positioning a large-current loop fault of a temporary color plate house in a construction site, which comprises the following steps: a fault type determination step, determining the fault type and performing pretreatment; a range determination step, determining the laying path of the fault line and delimiting the scanning range of the fault area; a preliminary determination step, scanning the line in the scanning range and preliminarily determining the fault position; and a determination step, detecting the fault position and determining the fault point.

[0005] Further, in the method for detecting and positioning a large-current loop fault of a temporary color plate house in a construction site, in the fault type determination step, whether there are signs of stable temperature rise, insulation layer odor and slight electrification of the metal frame in the fault line area is observed, the instantaneous metallic short circuit is excluded, and it is determined that the fault is a large-current loop fault.

[0006] Further, in the method for detecting and positioning a large-current loop fault of a temporary color plate house in a construction site, in the fault type determination step, the total power supply switch and the corresponding branch switch of the fault line are closed, a warning sign is hung, the outgoing line end of the total power supply switch, the outgoing line end of the branch switch and the exposed part of the line are tested in turn, and the combustible materials around the fault area are removed.

[0007] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, in the step of demarcating the range, the laying path of the fault line is determined according to the layout of the color plate house, and the key risk positions are marked.

[0008] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, in the step of demarcating the range, the suspected fault area is determined according to the laying path of the fault line, and the scanning range of the fault area is extended by a first preset distance on both sides of the suspected fault area as the center.

[0009] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, the preliminary determination step further comprises: a calibration sub-step of calibrating the temperature measuring instrument and setting the parameters of the temperature measuring instrument; a preliminary scanning sub-step of using the temperature measuring instrument to preliminarily scan the line in the scanning range and marking the abnormal position; and a dense scanning sub-step of densely scanning the abnormal position and preliminarily determining the fault position through the appearance observation of the line.

[0010] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, in the calibration sub-step, the temperature measuring instrument is zero-point calibrated, the temperature measuring mode of the temperature measuring instrument is set as point temperature measurement, and the emissivity and distance measuring ratio of the temperature measuring instrument are set.

[0011] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, in the preliminary scanning sub-step, the temperature measuring instrument keeps a second preset distance from the line, scans at a preset speed along the line direction, records a temperature value every third preset distance, compares the recorded temperature value with the temperature of the same specification line away from the fault area, and if the recorded temperature value is higher than the temperature of the same specification line away from the fault area by a preset value, the position corresponding to the recorded temperature value is determined as the abnormal position and is marked.

[0012] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, in the dense scanning sub-step, the temperature is measured every fourth preset distance within a preset range on both sides of the marked abnormal position as the center, the position with the highest temperature is determined as the suspected fault point, the appearance of the insulating layer of the suspected fault point is observed, and the fault position is preliminarily determined.

[0013] Further, in the method for detecting and positioning the fault of the large-current circuit of the temporary color plate house in the construction site, the determination step further comprises: measuring the continuity of the line at the fault position and the metal frame of the color plate house through the continuity range of the multimeter, and if the continuity is good, it is determined that there is a ground short circuit; measuring the ground insulation resistance of the line at the fault position through the megohmmeter; and if the measured ground insulation resistance is less than a preset resistance, the line at the fault position is disassembled, the inside of the line at the fault position is observed, and the fault point is determined.

[0014] In the present application, the fault type is first determined, and pre-processing is performed, then the laying path of the fault line is determined, and the scanning range of the fault area is demarcated, then the line in the scanning range is scanned, the fault position is preliminarily determined, then the fault position is detected, and finally the fault point is determined. In this way, through pre-processing-scanning preliminary determination-detection final determination, the fault point can be quickly and accurately identified without manual disassembly of the line, the detection time is saved, the troubleshooting efficiency is improved, the operation safety is guaranteed, and the problems of low troubleshooting efficiency and inability to quickly locate in the prior art are solved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the present application. Moreover, the same reference numerals are used throughout the same figures. In the drawings:

[0016] Figure 1 The flowchart of the detection and positioning method for the large-current loop fault of the construction site temporary color plate house provided by the embodiment of the present application;

[0017] Figure 2 In the detection and positioning method for the large-current loop fault of the construction site temporary color plate house provided by the embodiment of the present application, the structure diagram of marking the key risk parts;

[0018] Figure 3 In the detection and positioning method for the large-current loop fault of the construction site temporary color plate house provided by the embodiment of the present application, the structure diagram of the temperature measuring instrument scanning;

[0019] Figure 4 In the detection and positioning method for the large-current loop fault of the construction site temporary color plate house provided by the embodiment of the present application, the structure diagram of the determination step. DETAILED DESCRIPTION

[0020] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0021] Reference Figure 1 , Figure 1The flow chart of the construction site temporary color plate house large current loop fault detection and positioning method provided by the embodiment of the present application is shown in the figure. As shown in the figure, the construction site temporary color plate house large current loop fault detection and positioning method comprises the following steps:

[0022] The fault type determination step S1 determines the fault type and performs preprocessing.

[0023] Specifically, it is observed whether there are signs of stable temperature rise, insulation layer odor, and slightly charged metal frame in the fault line area, and transient metallic short circuit is excluded, and it is determined that the fault is a large current loop fault (not complete short circuit / short circuit to ground). More specifically, the contact resistance of the large current loop fault continuously generates heat, the temperature stably rises, but does not reach the degree of transient metallic short circuit, and then it is determined whether the fault is a large current loop fault according to the preliminary appearance judgment of the operator.

[0024] When it is confirmed that the fault is a large current loop fault, the total power supply switch and the corresponding branch switch of the fault line are closed, a warning sign of "prohibit closing" is hung, the total power supply switch outlet end, the branch switch outlet end and the line exposed part are tested in turn, and the combustible materials around the fault area are removed. Specifically, the total switch outlet end, the branch switch outlet end and the line exposed part are tested in turn with a test pen and a multimeter voltage range, and it is confirmed that there is no current and no voltage. The combustible materials (color plate sandwich materials, sundries, etc.) around the fault area are removed, a dry powder or carbon dioxide extinguisher is provided, and the operation environment is ensured to be safe.

[0025] The range determination step S2 determines the laying path of the fault line and the scanning range of the fault area.

[0026] Specifically, referring to Figure 2 , according to the layout diagram of the color plate house 5, the laying path of the fault line 1 is determined, and the key risk parts 2 are marked. In specific implementation, according to the layout diagram of the color plate house or on-site observation, the laying path of the fault line is determined. The key risk parts 2 include: joints, turning points, contact points with metal frames 4, and wall / pipe penetrating parts.

[0027] According to the laying path of the fault line, the fault suspected area is determined, and then the fault suspected area is taken as the center to extend a first preset distance to both sides as the scanning range of the fault area. Specifically, the fault suspected area is taken as the center to extend 3-5 meters to both sides as the subsequent temperature scanning coverage range, and it is ensured that there is no omission. In specific implementation, the first preset distance can be determined according to the actual situation, and the present embodiment does not make any limitation on this.

[0028] The preliminary determination step S3 preliminarily determines the fault position in the scanning range.

[0029] Specifically, the preliminary determination step S3 further comprises:

[0030] The temperature measuring instrument is calibrated and the parameters of the temperature measuring instrument are set in the calibration sub-step S31.

[0031] Specifically, the temperature measuring instrument is zero-point calibrated and the temperature measuring mode of the temperature measuring instrument is set as point temperature measurement, and the emissivity and distance ratio of the temperature measuring instrument are set. More specifically, the temperature measuring instrument is an infrared temperature measuring instrument.

[0032] When the temperature measuring instrument is zero-point calibrated, the temperature measuring instrument is turned on, and the zero point is calibrated by aligning with a dry normal temperature wall surface (known ambient temperature), and it is ensured that the display temperature has an error of ≤±1℃ from the ambient temperature. Then, the temperature measuring mode of the temperature measuring instrument is set as "point temperature measurement", the emissivity is adjusted to 0.9, and the distance ratio (D:S) is ≥10:1, so as to ensure the measurement accuracy.

[0033] In the preliminary scanning sub-step S32, the temperature measuring instrument is used to preliminarily scan the line in the scanning range, and the abnormal position is marked.

[0034] Specifically, the temperature measuring instrument is kept at a second preset distance from the line, and is uniformly scanned at a preset speed along the line direction, and a temperature value is recorded every third preset distance, and the recorded temperature value is compared with the temperature of the same specification line away from the fault area, and if the recorded temperature value is higher than the temperature of the same specification line away from the fault area by a preset value, the position corresponding to the recorded temperature value is determined as the abnormal position and is marked.

[0035] In actual implementation, the second preset distance, the preset speed, the third preset distance and the preset value can be determined according to actual conditions, and the present embodiment does not make any limitation on this. In the present embodiment, the second preset distance can be 10-30 cm, the third preset distance can be 50 cm, the preset speed ≤0.5 m / s, and the preset value is 5℃.

[0036] Referring to Figure 3 , the operator holds the infrared temperature measuring instrument 3, keeps a distance of 10-30 cm between the infrared temperature measuring instrument 3 and the fault line 1, and uniformly scans along the fault line 1 at a speed of ≤0.5 m / s, and records a temperature value every 50 cm, and compares the recorded temperature value with the temperature of the same specification normal line away from the fault area. When the recorded temperature value is higher than the temperature of the same specification normal line away from the fault area by ≥5℃, the infrared temperature measuring instrument is stopped for 3-5 seconds to confirm the stability of the temperature, and then a marker pen is used to mark the corresponding position, and the position is the abnormal position and the temperature value is marked. If the fault line 1 is covered by a thin color plate, the infrared temperature measuring instrument 3 scans the surface of the covering layer and marks the corresponding area.

[0037] In the dense scanning sub-step S33, the abnormal position is densely scanned, and the fault position is preliminarily determined through the appearance observation of the line.

[0038] Specifically, the temperature is measured every fourth preset distance within the preset range on both sides of the marked abnormal position, and the position point with the highest temperature is determined as the suspected fault point. The appearance of the insulating layer of the suspected fault point is observed to preliminarily determine the fault position.

[0039] In specific implementation, the preset range and the fourth preset distance can be determined according to actual conditions, and the present embodiment does not make any limitation on this. In the present embodiment, the fourth preset distance can be 10 cm.

[0040] For the marked abnormal position, point-by-point intensive scanning is performed within a range of 50 cm before and after the marked abnormal position, and the temperature is measured every 10 cm. The position point with the highest temperature is determined as the suspected fault point (such as point A in FIG. 6), and the appearance of the insulating layer of the suspected fault point is observed to preliminarily determine the fault position. Figure 3

[0041] The determining step S4 detects the fault position to determine the fault point.

[0042] Specifically, referring to FIG. 6, the determining step S4 further includes: Figure 4

[0043] The sub-step S41 measures the continuity of the line at the fault position and the metal frame of the color plate house through the continuity of the multimeter 6. If the continuity is good, it is determined that there is a short circuit to the ground.

[0044] The sub-step S42 measures the ground insulation resistance of the line at the fault position through the megohmmeter 7.

[0045] Specifically, the ground insulation resistance of the line at the fault position is measured by using a 500V megohmmeter.

[0046] The sub-step S43 disassembles the line at the fault position if the measured ground insulation resistance is less than a preset resistance, and observes the inside of the line at the fault position to determine the fault point.

[0047] Specifically, the preset resistance can be determined according to actual conditions, and the present embodiment does not make any limitation on this. In the present embodiment, the preset resistance is 0.5MΩ. If the measured ground insulation resistance is less than 0.5MΩ, the fault is further verified, the line at the fault position (including the color plate covering area) is disassembled, and whether there is a phenomenon of wire skin breakage or conductor contact with metal components is observed to finally confirm the fault point.

[0048] ​​It can be seen that in the embodiment, the fault type is first determined, and preprocessing is performed, then the laying path of the fault line is determined, the scanning range of the fault area is demarcated, the line in the scanning range is scanned, the fault position is preliminarily determined, and finally the fault point is determined. Through preprocessing-scanning preliminary determination-detection final determination, the fault point can be quickly and accurately identified without manual disassembly of the line, the detection time is saved, the troubleshooting efficiency is improved, the operation safety is guaranteed, and the problems of low troubleshooting efficiency and inability to quickly locate in the prior art are solved.

[0049] Implementation one: fault detection of lighting line in color plate house accommodation area of construction site

[0050] 1. Fault scenario

[0051] The color plate house accommodation area is temporarily set in the construction site, the room lighting lamps flicker, and the metal frame near the corner has a slight numbness, suspecting that the line is electrified, and the preliminary judgment is that the large current loop is faulty, and the ground is short-circuited.

[0052] 2. Implementation steps

[0053] 2.1 Safety preprocessing:

[0054] Close the total switch of the lighting line in the accommodation area, and hang a “no closing” warning sign.

[0055] Test the total switch outlet with a test pen, and the neon tube does not emit light; measure the line-to-ground voltage with a multimeter voltage range, and the display is 0V, confirming that there is no electricity.

[0056] Remove the combustible materials such as cartons and clothes around the corner, and place a dry powder fire extinguisher.

[0057] 2.2 Line layout combing:

[0058] Observe the line direction on site: the lighting line is laid along the top of the color plate house metal frame, passes through 3 turns and 2 joints, directly contacts the metal frame near the corner without insulation isolation, and takes this area as the suspected area of the corner. With the suspected area of the corner as the center, extend 3 meters to both sides, cover 2 joints and 3 turns.

[0059] 2.3 Calibration and setting of temperature measuring instrument:

[0060] Select an infrared temperature measuring instrument with an accuracy of ±1℃ and a measuring distance ratio of 12:1, calibrate it against the wall (environmental temperature 26℃), and the display temperature is 26.5℃, the error is ≤0.5℃, which meets the requirements. Then, set the emissivity of the infrared temperature measuring instrument to 0.9 and the temperature measurement mode to “point temperature measurement”.

[0061] 2.4 Subsection scanning and abnormal marking:

[0062]

[0062] The handheld infrared thermometer is kept 20 cm away from the line, and scans at a speed of 0.3 m / s, recording the temperature every 50 cm, where the normal line temperature is 26-27°C. At the point where the wall corner line contacts the metal frame, the temperature reaches 38°C, which is 11°C higher than the normal line. After staying for 5 seconds, the temperature stabilizes at 38.2°C, and the point is marked with a marker pen, such as point A, which is the abnormal position.

[0063] 2.5 Precise positioning:

[0064] Intensive scanning is performed within a range of 50 cm before and after point A, with measurements taken every 10 cm. At 10 cm to the left of point A, the temperature is 32°C, at point A it is 38.2°C, and at 15 cm to the right of point A, the temperature is 30°C, confirming that point A is the highest temperature point, which is the suspected fault point.

[0065] Observing that the line insulation layer at point A is yellow-brown with slight softening marks, it is preliminarily judged to be the fault location.

[0066] 2.6 Tool verification:

[0067] Using the continuity test of the multimeter, the continuity between the line at point A and the metal frame is measured, showing conduction, confirming the ground short circuit.

[0068] Using the megohmmeter to measure the line-to-ground insulation resistance, the reading is 0.2 MΩ, which is less than 0.5 MΩ, meeting the fault characteristics.

[0069] Disassembling the insulation layer of the line at point A, it is found that the copper core of the conductor has broken skin and directly contacts the metal frame of the color plate house, finally confirming the fault point.

[0070] 3. Fault handling

[0071] Replace the damaged section of the line, fix the line to the metal frame with an insulating clamp to avoid direct contact, and double wrap the joint with insulating tape + heat shrink tube. After restoring power, there is no abnormality. The troubleshooting time is 25 minutes, which is 1.5 hours less than traditional manual troubleshooting.

[0072] In summary, the embodiment has the following characteristics:

[0073] 1. High efficiency and speed: Through segmented scanning with the thermometer, the fault range can be narrowed down and the fault point can be located in a short time, greatly improving the troubleshooting efficiency compared to traditional manual troubleshooting.

[0074] 2. Precise positioning: Combined with the three-level positioning logic of "preliminary scanning - intensive scanning - tool verification", the positioning error of the fault point is ≤10 cm, avoiding misjudgment and omission.

[0075] 3. Safety and reliability: Strictly implement the power-off and electricity checking process, prohibit live operation, and reduce the risk of electric shock and fire.

[0076] 4. Strong versatility: adapt to various types of temporary color plate house (accommodation house, office, warehouse) lighting and power lines in construction site, without the need for special equipment modification.

[0077] 5. Simple operation: after training, the operating personnel can implement it, which meets the rapid disposal needs of the construction site.

[0078] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the direction or positional relationship of the terms based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation to the present application.

[0079] In addition, it should be noted that in the description of the present application, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between the two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0080] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites, characterized in that, Includes the following steps: The steps for determining the fault type are as follows: determine the fault type and perform preprocessing. The steps for defining the scope include determining the laying path of the faulty line and defining the scanning range of the faulty area; The initial steps involve scanning the lines within the scanning range to preliminarily determine the location of the fault. The steps are defined to detect the fault location and determine the fault point.

2. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 1, characterized in that, In the fault type determination step Observe whether there is a steady temperature rise in the faulty circuit area, an unusual odor from the insulation layer, or slight signs of electrification in the metal frame. Rule out a momentary metallic short circuit and determine that the fault is a high-current circuit fault.

3. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 1, characterized in that, In the fault type determination step Turn off the main power switch and corresponding branch switches of the faulty circuit, hang a warning sign, test the output terminals of the main power switch, the output terminals of the branch switches and the exposed parts of the circuit in sequence, and remove flammable materials around the fault area.

4. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 1, characterized in that, In the step of defining the range Based on the layout diagram of the prefabricated house, determine the laying path of the faulty line and mark the key risk areas.

5. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 4, characterized in that, In the step of defining the range Based on the laying path of the faulty line, a suspected fault area is determined, and a first preset distance is extended to both sides of the suspected fault area as the scanning range of the fault area.

6. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 1, characterized in that, The preliminary determination step further includes: The calibration sub-step involves calibrating the thermometer and setting its parameters. The preliminary scanning sub-step involves using the temperature measuring instrument to perform a preliminary scan of the lines within the scanning range and marking any abnormal locations. The dense scanning sub-step involves performing a dense scan on the abnormal location and initially determining the fault location by visually inspecting the line.

7. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 6, characterized in that, In the calibration sub-step The thermometer is zero-point calibrated, and its temperature measurement mode is set to point temperature measurement. The emissivity and ranging ratio of the thermometer are also set.

8. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 6, characterized in that, In the preliminary scanning sub-step The thermometer maintains a second preset distance from the line and scans along the line at a preset speed. It records the temperature value every third preset distance and compares the recorded temperature value with the temperature of a line of the same specification away from the fault area. If the recorded temperature value is higher than the temperature of the line of the same specification away from the fault area by a preset value, the location corresponding to the recorded temperature value is identified as an abnormal location and marked.

9. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 6, characterized in that, In the dense scanning sub-step The temperature is measured every fourth preset distance from the marked abnormal location to both sides, and the location with the highest temperature is identified as the suspected fault point. The appearance of the insulation layer of the suspected fault point is observed to preliminarily determine the fault location.

10. The method for detecting and locating high-current circuit faults in temporary prefabricated steel sheet buildings at construction sites according to claim 1, characterized in that, The determining step further includes: The continuity test is performed on the line at the fault location and the metal frame of the prefabricated house using a multimeter in continuity mode. If the line is continuous, a short circuit to ground is confirmed. The insulation resistance to ground of the line at the fault location was measured using a megohmmeter. If the measured insulation resistance to ground is less than the preset resistance, the line at the fault location is disassembled, the interior of the line at the fault location is observed, and the fault point is determined.

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