Bending fatigue test method for power cable

Abstract

The invention relates to the field of cable detection, in particular to a bending fatigue test method for a power cable, which comprises a test device body, a shielding cover, a connecting rod, a limiting plate, an electric slide rail I and the like, a shielding cover is rotationally connected to the testing device body, and a plurality of handles are arranged on the shielding cover; the testing device body and the shielding cover are jointly connected with a plurality of connecting rods in a sliding manner; a plurality of limiting plates are fixedly connected in the testing device body; an electric sliding rail I is fixedly connected into the testing device body and located in front of the limiting plate. According to the invention, the test frame replaces a cable drag chain for testing, the flexible boards are arranged on the test frame, the adjacent flexible boards are attached to each other, when a new cable needs to be detected, after the tested cable is pulled out of the test frame, the new cable is pressed on the flexible boards, and the attached flexible boards are pushed away by the new cable; therefore, a new cable can be sent into the test frame, thereby facilitating the detection of the cable.

Description

Technical Field

[0001] The invention relates to the field of cable detection, and in particular to a bending fatigue testing method for a power cable. Background Art

[0002] Drag chain cable is a highly flexible special cable that can move back and forth with the drag chain without being easily worn. It is called drag chain cable. It is also commonly called towing cable or tank chain cable.

[0003] In situations where equipment units need to move back and forth, in order to prevent the cables from getting entangled, worn, pulled off, hung and scattered, the cables are often placed in cable drag chains to protect the cables, and the cables can also move back and forth with the drag chains.

[0004] The existing detection method for cable bending test is too simple, the bending angle of the cable is small, the actual bending angle of the cable is limited, and the bending frequency of the cable is low, which cannot well test the real data of the cable during use.

[0005] After the test of the batch of cables is completed, the tested cables need to be pulled out from the cable drag chain, and then the cover plate on the cable drag chain needs to be removed before new cables can be put into the cable drag chain for subsequent testing, which is rather troublesome. Summary of the invention

[0006] In order to overcome the shortcoming that the existing detection method for cable bending test is too single, the present invention provides a bending fatigue test method for power cables.

[0007] The technical implementation scheme of the present invention is:

[0008] A bending fatigue test method for power cables comprises the following steps: step 1: a worker opens a cable detection device, places a cable drag chain in the cable detection device, and fixes the cable in the cable drag chain; step 2: starting the cable detection device to start bending test of the cable in the cable drag chain; step 3: pushing one end of the cable drag chain through a pushing structure to increase the degree of change of the bending angle of the cable drag chain, increase the bending angle of the cable drag chain, and increase the bending frequency of the cable drag chain, so that the bending of the cable drag chain is more varied; step 4: turning the cable drag chain over The rotating structure drives one end of the cable drag chain to swing up and down repeatedly, thereby further increasing the bending angle of the cable drag chain and the bending variation of the cable drag chain. Step five: The cable drag chain is adjusted and pushed by the lifting structure to adjust the cable drag chain as a whole into a letter shape, so that the letter-shaped cable drag chain is continuously compressed and stretched, thereby further increasing the bending variation of the cable. Step six: The gravel is transported to the cable detection device through the gravel transporting structure. During the cable detection process, the gravel enters the cable drag chain and rubs against the cable, thereby detecting the scene where the cable is bent by the additional friction.

[0009] The cable detection device includes a test device body, a shielding cover, a connecting rod, a limiting plate, an electric slide rail I, a moving block I and a mounting block; the test device body is rotatably connected to the shielding cover, and the shielding cover is provided with a plurality of handles; the test device body and the shielding cover are slidably connected to a plurality of connecting rods; a plurality of limiting plates are fixedly connected in the test device body; an electric slide rail I is fixedly connected in the test device body, and the electric slide rail I is located in front of the limiting plate; a moving block I is slidably connected to the electric slide rail I; a mounting block is installed on the moving block I; it also includes an electric retractor and a mounting frame I; the mounting block is rotatably connected to the electric retractor; the retracting part of the electric retractor is installed with the mounting frame I, and a limiting buckle I is provided on the mounting frame I.

[0010] Furthermore, a driving motor I is provided at the connection between the electric telescopic device and the mounting block.

[0011] Furthermore, a test frame is also included; the test frame is arranged inside the test device body, and a plurality of soft boards are arranged on the front and rear sides of the test frame, and adjacent soft boards are attached to each other.

[0012] Furthermore, it also includes a heating tube; a plurality of evenly distributed heating tubes are arranged in the test frame.

[0013] Furthermore, it also includes support rods; a plurality of support rods are arranged on the front and rear sides of the test frame.

[0014] Furthermore, it also includes an electric guide rail I, an electric push rod I and a limiting roller I; the electric guide rail I is installed on the moving block I, and the mounting block is slidably connected to the electric guide rail I; the electric push rod I is fixedly connected to the rear side of the mounting block; and the limiting roller I is installed on the telescopic part of the electric push rod I.

[0015] Furthermore, it also includes a conveyor belt, a push plate, a mounting plate, an electric push rod II and a storage frame; a conveyor belt is installed on the test device body, and a drive motor II is provided on the conveyor belt; a plurality of push plates are provided on the conveyor belt; a plurality of mounting plates are provided at the bottom of the test device body; electric push rods II are provided on all mounting plates; and a storage frame for storing gravel is commonly installed on the telescopic parts of all electric push rods II.

[0016] Furthermore, it also includes an air pipe; a plurality of air pipes are arranged in the test device body, and air holes are opened on the air pipes.

[0017] Furthermore, it also includes an electric slide rail II, a detection component and an installation frame II; the electric slide rail II is installed in the test device body; a number of detection components are installed on the electric slide rail II; the test device body is fixedly connected to the installation frame II, and the installation frame II is provided with a limiting buckle II; the detection component includes a moving block II, an electric push rod III, an electric guide rail II and a limiting roller II; the moving block II is slidably connected in the electric slide rail II; the electric push rod III is fixedly connected to the moving block II; the electric guide rail II is installed on the telescopic part of the electric push rod III; the limiting roller II is slidably connected to the electric guide rail II.

[0018] Beneficial effect: The present invention controls the electric retractor to repeatedly push out and retract to drive the installation frame I and the cable drag chain fixed on the installation frame I to move back and forth left and right, thereby increasing the degree of change of the bending angle of the cable drag chain, increasing the bending angle of the cable drag chain, and at the same time increasing the bending frequency of the cable drag chain, making the bending of the cable drag chain more varied and better for cable detection.

[0019] The present invention provides a driving motor I at the connection between the electric retractor and the mounting block. When performing a bending test on the cable in the cable drag chain, the driving motor I is started to drive the electric retractor, the mounting frame I and the cable drag chain fixed on the mounting frame I to repeatedly swing up and down, thereby further increasing the bending angle of the cable drag chain and the bending variation of the cable drag chain, thereby improving the comprehensiveness of cable detection.

[0020] The present invention uses a test frame to replace the cable drag chain for testing. By arranging a soft board on the test frame, adjacent soft boards are fitted together. When a new cable needs to be tested, the cable that has completed the test is pulled out from the test frame, and a new cable is pressed onto the soft board. The new cable pushes the fitted soft board away, and the new cable can be sent into the test frame, which is convenient for cable testing.

[0021] The present invention controls the electric guide rail I to drive the mounting block to move upward, and controls the electric push rod I to retract to drive the limiting roller I to push in the direction of the test frame, so that the test frame begins to bend and deform. At this time, the test frame is in the shape of a letter "U", and then controls the electric guide rail I to drive the mounting block to be unable to move up and down. At the same time, controls the electric push rod I to repeatedly push out or retract to drive the limiting roller I to move back and forth left and right, so that the test frame in the shape of a letter "U" is continuously compressed and stretched, so that the bending change of the cable is further increased, which is beneficial to the bending detection of the cable.

[0022] The present invention drives the gravel in the storage frame upward through the conveyor belt and the push plate. When the cable is tested, the test frame is pressed on the gravel on the conveyor belt, and part of the gravel enters the test frame to rub against the cable, so as to detect the scene when the cable is bent due to the additional friction, thereby increasing the diversity of cable testing of the present invention.

[0023] The present invention adds an air pipe in the test device body, and the air pipe is connected to an external air source. When the test frame is pressed on the gravel on the conveyor belt, the external air source is started to transport air into the air pipe, and the air is blown out from the air holes on the air pipe. The blown air blows the gravel on the conveyor belt to change the position of the gravel on the conveyor belt, so that the test frame is pressed on the gravel at different positions and in different states, which makes it easier for the gravel to enter the test frame and rub against the cable.

[0024] The present invention controls the electric push rod III to push out and drive the electric guide rail II, the limiting roller II and the test frame to move upward to adjust the bending angle of the test frame, and at the same time controls the electric slide rail II to drive the moving block II to move to change the distance between the moving blocks II, so that the present invention can bend the test frame at different angles and different folding degrees, making the present invention more comprehensive in detecting the test frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the overall structure of the cable detection device disclosed in the present invention from a first viewing angle;

[0026] Figure 2 A schematic diagram of the overall structure of a second viewing angle disclosed by the bending fatigue testing method for power cables of the present invention;

[0027] Figure 3 It is a structural cross-sectional view of the testing device body disclosed in the present invention;

[0028] Figure 4 It is a structural schematic diagram of the conveyor belt, the push plate, the mounting plate, the electric push rod II, the storage frame, the air pipe and the drive motor II disclosed in the present invention;

[0029] Figure 5The structural diagram of the limiting plate, electric slide rail I, moving block I, mounting block, electric retractor, mounting frame II and limiting buckle II disclosed in the present invention;

[0030] Figure 6 It is a structural schematic diagram of the mounting block, electric retractor, mounting frame I, electric guide rail I, electric push rod I, limiting roller I, driving motor I and limiting buckle I disclosed in the present invention;

[0031] Figure 7 It is a schematic diagram of the structure of the test frame, heating tube, support rod and soft board disclosed in the present invention;

[0032] Figure 8 The present invention is a schematic structural diagram of an electric slide rail II, a moving block II, an electric push rod III, an electric guide rail II and a limiting roller II disclosed in the present invention.

[0033] The meanings of the reference numerals in the figure are as follows: 1-test device body, 2-shielding cover, 3-connecting rod, 4-limiting plate, 5-electric slide rail I, 6-moving block I, 7-mounting block, 8-electric telescopic device, 9-mounting frame I, 10-test frame, 11-heating tube, 12-support rod, 101-electric guide rail I, 102-electric push rod I, 103-limiting roller I, 110-conveyor belt, 111-pushing plate, 112-mounting plate, 113-electric push rod II, 114-storage frame, 115-trachea, 201-electric slide rail II, 202-moving block II, 203-electric push rod III, 204-electric guide rail II, 205-limiting roller II, 206-mounting frame II, 21-handle, 81-driving motor I, 91-limiting buckle I, 1001-soft board, 1101-driving motor II, 2061-limiting buckle II. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] A bending fatigue testing method for a power cable comprises the following steps:

[0037] Step 1: The staff opens the cable detection device, places the cable drag chain in the cable detection device, and puts the cable into the cable drag chain for fixing;

[0038] Step 2: Start the cable detection device to perform a bending test on the cables in the cable drag chain;

[0039] Step 3: Push one end of the cable drag chain through the pushing structure to increase the degree of change of the bending angle of the cable drag chain, increase the bending angle of the cable drag chain, and increase the bending frequency of the cable drag chain, so that the bending of the cable drag chain is more varied;

[0040] Step 4: Use the flipping structure to drive one end of the cable drag chain to swing up and down repeatedly, thereby further increasing the bending angle of the cable drag chain and increasing the bending variation of the cable drag chain;

[0041] Step 5: Use the lifting structure to adjust and push the cable drag chain, adjust the cable drag chain as a whole to a 3 shape, so that the cable drag chain in the shape of a 3 is continuously compressed and stretched, and the bending change of the cable is further increased;

[0042] Step 6: The gravel is transported to the cable detection device through the gravel conveying structure. During the cable detection process, the gravel enters the cable drag chain and rubs against the cable, and the detection cable is bent due to additional friction.

[0043] like Figure 1-Figure 7 As shown, the cable detection device includes a test device body 1, a shielding cover 2, a connecting rod 3, a limiting plate 4, an electric slide rail Ⅰ5, a moving block Ⅰ6 and a mounting block 7; the test device body 1 is rotatably connected to the shielding cover 2, and the shielding cover 2 is provided with two handles 21; the test device body 1 and the shielding cover 2 are slidably connected to two connecting rods 3; two limiting plates 4 are fixedly connected in the test device body 1, and the detection area is between all the limiting plates 4; the test device body 1 is fixedly connected to the electric slide rail Ⅰ5, and the electric slide rail Ⅰ5 is located in front of the limiting plate 4; the moving block Ⅰ6 is slidably connected to the electric slide rail Ⅰ5; the moving block Ⅰ6 is mounted with the mounting block 7;

[0044] It also includes an electric retractor 8 and a mounting frame Ⅰ9; the electric retractor 8 is rotatably connected to the mounting block 7; the telescopic part of the electric retractor 8 is installed with a mounting frame Ⅰ9, and a limiting buckle Ⅰ91 is provided on the mounting frame Ⅰ9 to facilitate fixing the cable drag chain.

[0045] A driving motor I81 is provided at the connection between the electric retractor 8 and the mounting block 7, which further increases the bending angle of the cable drag chain and increases the bending variation of the cable drag chain.

[0046] The test device also includes a test frame 10 ; the test frame 10 is disposed in the test device body 1 , and two soft boards 1001 are disposed on the front and rear sides of the test frame 10 , and adjacent soft boards 1001 are attached to each other.

[0047] A heating tube 11 is also included; a plurality of evenly distributed heating tubes 11 are arranged in the test frame 10 .

[0048] The test frame 10 also includes support rods 12 ; a plurality of support rods 12 are disposed on the front and rear sides of the test frame 10 .

[0049] It also includes an electric guide rail Ⅰ101, an electric push rod Ⅰ102 and a limiting roller Ⅰ103; the electric guide rail Ⅰ101 is installed on the moving block Ⅰ6, and the mounting block 7 is slidably connected to the electric guide rail Ⅰ101; the electric push rod Ⅰ102 is fixedly connected to the rear side of the mounting block 7; the limiting roller Ⅰ103 is installed on the telescopic part of the electric push rod Ⅰ102.

[0050] Before the present invention works, the shielding cover 2 is opened upward by manually holding the handle 21, and the telescopic part of the connecting rod 3 is pulled out synchronously. When the shielding cover 2 is opened upward to the position shown in FIG. Figure 2 After the opening state is shown, the cable drag chain is placed in the detection area formed between all the limiting plates 4, one end of the cable drag chain is fixed in the test device body 1, and the other end of the cable drag chain is clamped in the installation frame Ⅰ9. The other end of the cable drag chain is restricted and fixed by the limiting buckle Ⅰ91 on the installation frame Ⅰ9, and then the cover plate on the cable drag chain is removed. After the cable to be tested is placed in the cable drag chain, the cover plate is reinstalled on the cable drag chain. After that, both ends of the cable are fixed on the cable drag chain, and preparations are made to start the cable test. The electric slide rail Ⅰ5 is controlled to drive the moving block Ⅰ6, the mounting block 7, the electric retractor 8, the mounting frame Ⅰ9 and the cable drag chain fixed on the mounting frame Ⅰ9 to move back and forth left and right, and the bending test of the cable in the cable drag chain is started.

[0051] Considering that the existing detection method for the bending test of the cable is too single, the bending angle of the cable is small, the actual bending angle of the cable is limited, and the bending frequency of the cable is low, it is impossible to test the real data of the cable during use. By adding an electric retractor 8 to the mounting block 7, the mounting frame Ⅰ9 is installed on the telescopic part of the electric retractor 8. When the bending test of the cable in the cable drag chain is performed, the bending angle of the cable drag chain is fixedly changed. By controlling the electric retractor 8 to repeatedly push out and retract, the mounting frame Ⅰ9 and the cable drag chain fixed on the mounting frame Ⅰ9 are driven to move back and forth left and right, so that the degree of change of the bending angle of the cable drag chain is increased, the bending angle of the cable drag chain is increased, and the bending frequency of the cable drag chain is increased, so that the bending of the cable drag chain is more varied, and the cable detection is better performed.

[0052] A driving motor Ⅰ81 is provided at the connection between the electric retractor 8 and the mounting block 7. When performing a bending test on the cable in the cable drag chain, the driving motor Ⅰ81 is started to drive the electric retractor 8, the mounting frame Ⅰ9 and the cable drag chain fixed on the mounting frame Ⅰ9 to repeatedly swing up and down, thereby further increasing the bending angle of the cable drag chain and the bending changes of the cable drag chain, thereby improving the comprehensiveness of cable detection.

[0053] Considering that after completing the test of the batch of cables, the tested cables need to be pulled out from the cable drag chain, and then the cover plate on the cable drag chain needs to be removed before new cables can be placed in the cable drag chain for subsequent testing, which is rather troublesome. The test is performed by using a test frame 10 instead of the cable drag chain. By arranging a soft board 1001 on the test frame 10, adjacent soft boards 1001 fit together. When it is necessary to test a new cable, after pulling out the tested cables from the test frame 10, the new cable is pressed onto the soft board 1001. The new cable pushes the fitted soft board 1001 away, and the new cable can be sent into the test frame 10 to facilitate the cable testing.

[0054] By adding a heating tube 11 in the test frame 10, when performing a bending test on the cable in the cable drag chain, the heating tube 11 is started, and the heating tube 11 begins to heat up, thereby increasing the temperature in the test frame 10, simulating the cable to be tested in a high temperature environment. By installing the heating tube 11 in the test frame 10, the heat is limited within the test frame 10, thereby better simulating the use of the cable in a high temperature environment.

[0055] Considering that after adding a soft board 1001 to the test frame 10, although it is convenient to replace the cable, the test frame 10 loses its original supporting force and cannot simulate the original supporting force of the cable drag chain. When the test frame 10 is deformed, the cables in the test frame 10 will suffer additional damage, affecting the detection. By adding a support rod 12 to the test frame 10, the support rod 12 can make up for the lost supporting force of the test frame 10, so as to better perform cable detection.

[0056] It should be noted that after adding support rods 12 to the test frame 10, when placing a new cable into the test frame 10, the new cable needs to be inserted into all the support rods 12 on the corresponding side in turn before the new cable can be pressed onto the flexible board 1001 and sent into the test frame 10.

[0057] By adding an electric guide rail Ⅰ101, an electric push rod Ⅰ102 and a limiting roller Ⅰ103 to the mounting block 7, when testing the cable, the electric guide rail Ⅰ101 is controlled to drive the mounting block 7 to move upward, and the electric push rod Ⅰ102 is controlled to retract to drive the limiting roller Ⅰ103 to push toward the test frame 10, so that the test frame 10 begins to bend and deform. At this time, the test frame 10 is in a 3 shape as a whole, and then the electric guide rail Ⅰ101 is controlled to drive the mounting block 7 to move up and down, and the electric push rod Ⅰ102 is controlled to repeatedly push out or retract to drive the limiting roller Ⅰ103 to move back and forth left and right, so that the overall test frame 10 in the shape of a 3 is continuously compressed and stretched, so that the bending changes of the cable are further increased, which is beneficial to the bending detection of the cable.

[0058] Example 2

[0059] On the basis of Example 1, Figure 2-Figure 4 and Figure 8 As shown, it also includes a conveyor belt 110, a push plate 111, a mounting plate 112, an electric push rod II 113 and a storage frame 114; a conveyor belt 110 is installed on the test device body 1, and a driving motor II 1101 is provided on the conveyor belt 110; a plurality of push plates 111 are provided on the conveyor belt 110; two mounting plates 112 are provided at the bottom of the test device body 1; electric push rods II 113 are provided on all the mounting plates 112; and a storage frame 114 is installed on the telescopic parts of all the electric push rods II 113.

[0060] The test device body 1 also includes an air pipe 115 ; two air pipes 115 are arranged in the test device body 1 , and air holes are opened on the air pipes 115 .

[0061] It also includes an electric slide rail II 201, a detection component and a mounting frame II 206; the electric slide rail II 201 is installed in the test device body 1; a number of detection components are installed on the electric slide rail II 201; a mounting frame II 206 is fixedly connected in the test device body 1, and a limiting buckle II 2061 is provided on the mounting frame II 206; the detection component includes a moving block II 202, an electric push rod III 203, an electric guide rail II 204 and a limiting roller II 205; the moving block II 202 is slidably connected in the electric slide rail II 201; the electric push rod III 203 is fixedly connected to the moving block II 202; the electric guide rail II 204 is installed on the telescopic part of the electric push rod III 203; the limiting roller II 205 is slidably connected to the electric guide rail II 204.

[0062] By adding a mounting plate 112, an electric push rod II 113 and a storage frame 114 at the bottom of the test device body 1, before testing the cable, enough crushed stones are put into the storage frame 114, and the electric push rod II 113 is controlled to push out and drive the storage frame 114 to move upward. When the storage frame 114 is fitted with the test device body 1, the electric push rod II 113 stops pushing out, and the drive motor II 1101 is started. The conveyor belt 110 rotates clockwise from the front to the back, and the push plate 111 rotates accordingly. During the rotation of the push plate 111, the conveyor belt 110 and the push plate 111 drive the crushed stones in the storage frame 114 upward. When the cable is tested, the test frame 10 presses the crushed stones on the conveyor belt 110. The test frame 10 is pressed on the gravel on the conveyor belt 110, and some of the gravel enters the test frame 10 and rubs against the cable. The scene when the cable is bent by the additional friction is detected, thereby increasing the diversity of cable detection of the present invention. An air pipe 115 is added in the test device body 1, and the air pipe 115 is connected to an external air source. When the test frame 10 is pressed on the gravel on the conveyor belt 110, the external air source is started to transport air into the air pipe 115, and the air is blown out from the air holes on the air pipe 115. The blown air blows the gravel on the conveyor belt 110, so that the position of the gravel on the conveyor belt 110 changes, and the test frame 10 is pressed on the gravel in different positions and different states, which facilitates the gravel to enter the test frame 10 and rub against the cable.

[0063] By adding an electric slide rail II 201, a moving block II 202, an electric push rod III 203, an electric guide rail II 204, a limiting roller II 205 and an installation frame II 206 in the test device body 1, when it is necessary to perform a bending test on the cable, one end of the test frame 10 is clamped on the installation frame II 206, the test frame 10 is fixed by a limiting buckle II 2061, the test frame 10 is placed on the limiting roller II 205, and the electric guide rail II 204 is controlled to drive the limiting roller II 205 and the test frame 10 to move forward. After the middle part of 05 is aligned with the middle part of the installation frame II 206, the limiting roller II 205 stops moving, and the electric push rod III 203 is controlled to push out and drive the electric guide rail II 204, the limiting roller II 205 and the test frame 10 to move upward to adjust the bending angle of the test frame 10. At the same time, the electric slide rail II 201 is controlled to drive the moving block II 202 to move and change the distance between the moving blocks II 202, so that the present invention can bend the test frame 10 at different angles and different folding degrees, making the present invention more comprehensive in detecting the test frame 10.

[0064] Although the present invention is described in detail with reference to the above embodiments, it is obvious to those skilled in the art through this disclosure that various changes or modifications may be made to the present invention without departing from the principle and spirit of the present invention defined by the claims. Therefore, the detailed description of the embodiments of the present disclosure is only used to explain, not to limit the present invention, but the scope of protection is limited by the content of the claims.

Claims

1. A bending fatigue test method for power cables, characterized in that: The following steps are included: Step 1: The staff opens the cable detection device and places the cable drag chain inside the cable detection device. Put the cable into the cable drag chain to secure it; Step 2: Start the cable detection device to perform a bending test on the cables in the cable drag chain; Step 3: Push one end of the cable drag chain through the pushing structure to increase the degree of change of the bending angle of the cable drag chain, increase the bending angle of the cable drag chain, and increase the bending frequency of the cable drag chain, so that the bending of the cable drag chain is more varied; Step 4: Use the flipping structure to drive one end of the cable drag chain to swing up and down repeatedly, thereby further increasing the bending angle of the cable drag chain and increasing the bending variation of the cable drag chain; Step 5: The cable drag chain is adjusted and pushed by the lifting structure to form a U-shape as a whole, so that the U-shaped cable drag chain is continuously compressed and stretched, and the bending change of the cable is further increased; Step 6: The gravel is transported to the cable detection device through the gravel conveying structure. During the cable detection process, the gravel enters the cable drag chain and rubs against the cable, and the detection cable is bent due to additional friction.

2. A bending fatigue testing method for power cables according to claim 1, characterized in that: In step 1, the cable detection device comprises a test device body (1), a shielding cover (2), a connecting rod (3), a limiting plate (4), an electric slide rail I (5), a moving block I (6) and a mounting block (7); the test device body (1) is rotatably connected to the shielding cover (2), and the shielding cover (2) is provided with a plurality of handles (21); the test device body (1) and the shielding cover (2) are slidably connected to a plurality of connecting rods (3); a plurality of limiting plates (4) are fixedly connected to the test device body (1) ; An electric slide rail I (5) is fixedly connected to the inside of the test device body (1), and the electric slide rail I (5) is located in front of the limiting plate (4); a moving block I (6) is slidably connected to the electric slide rail I (5); a mounting block (7) is installed on the moving block I (6); it also includes an electric telescopic device (8) and a mounting frame I (9); the mounting block (7) is rotatably connected to the electric telescopic device (8); the telescopic part of the electric telescopic device (8) is installed with a mounting frame I (9), and a limiting buckle I (91) is provided on the mounting frame I (9).

3. A bending fatigue testing method for a power cable according to claim 2, characterized in that: A driving motor I (81) is provided at the connection between the electric telescopic device (8) and the mounting block (7).

4. A bending fatigue testing method for a power cable according to claim 2, characterized in that: It also includes a test frame (10); the test frame (10) is arranged inside the test device body (1), and a plurality of soft boards (1001) are arranged on the front and rear sides of the test frame (10), and adjacent soft boards (1001) are attached to each other.

5. A bending fatigue testing method for a power cable according to claim 3, characterized in that: It also includes a heating tube (11); a plurality of evenly distributed heating tubes (11) are arranged in the test frame (10).

6. A bending fatigue testing method for power cables according to claim 4, characterized in that: It also includes support rods (12); a plurality of support rods (12) are arranged on the front side and the rear side of the test frame (10).

7. A bending fatigue testing method for a power cable according to claim 5, characterized in that: It also includes an electric guide rail I (101), an electric push rod I (102) and a limiting roller I (103); the electric guide rail I (101) is installed on the moving block I (6), and the mounting block (7) is slidably connected to the electric guide rail I (101); the electric push rod I (102) is fixedly connected to the rear side of the mounting block (7); and the limiting roller I (103) is installed on the telescopic part of the electric push rod I (102).

8. A bending fatigue testing method for a power cable according to claim 6, characterized in that: The test device also comprises a conveyor belt (110), a push plate (111), a mounting plate (112), an electric push rod II (113) and a storage frame (114); the conveyor belt (110) is mounted on the test device body (1), and a driving motor II (1101) is mounted on the conveyor belt (110); a plurality of push plates (111) are mounted on the conveyor belt (110); a plurality of mounting plates (112) are mounted on the bottom of the test device body (1); electric push rods II (113) are mounted on all mounting plates (112); and a storage frame (114) for storing crushed stones is mounted on the telescopic parts of all electric push rods II (113).

9. A bending fatigue testing method for a power cable according to claim 7, characterized in that: It also includes an air pipe (115); a plurality of air pipes (115) are arranged in the testing device body (1), and air holes are opened on the air pipes (115).

10. A bending fatigue testing method for power cables according to claim 8, characterized in that: The invention also comprises an electric slide rail II (201), a detection component and an installation frame II (206); the electric slide rail II (201) is installed in the test device body (1); a plurality of detection components are installed on the electric slide rail II (201); the installation frame II (206) is fixedly connected in the test device body (1), and a limiting buckle II (2061) is provided on the installation frame II (206); the detection component comprises a moving block II (202), an electric push rod III (203), an electric guide rail II (204) and a limiting roller II (205); the moving block II (202) is slidably connected in the electric slide rail II (201); the moving block II (202) is fixedly connected to the electric push rod III (203); the telescopic part of the electric push rod III (203) is installed with the electric guide rail II (204); and the limiting roller II (205) is slidably connected to the electric guide rail II (204).

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