Overhead cable test device, current-carrying capacity test method and thermal cycle test method

Abstract

The invention provides an overhead cable test device which comprises two tension assemblies which are oppositely arranged and can be far away from each other, and the two tension assemblies are used for being connected with the two ends of a tested cable and tensioning the tested cable; the power supply assembly is connected with the two tension assemblies and is used for applying current to the tested cable; the temperature measuring assembly is used for measuring the temperature of the measured cable and the environment temperature which is a set distance away from the measured cable; and the control assembly is electrically connected with the temperature measurement assembly and the power supply assembly and is used for adjusting the current output by the power supply assembly according to the measurement result of the temperature measurement assembly. The invention also provides a current-carrying capacity test method and a thermal cycle test method using the overhead cable test device. By adopting the overhead cable test device, the current-carrying capacity of the overhead cable and the accuracy, reproducibility and test efficiency of a thermal cycle test can be greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cable testing, in particular to an overhead cable testing device, ampacity testing method and thermal cycle testing method. BACKGROUND

[0002] Currently, 35kV and above overhead conductors need to carry out ampacity testing and thermal cycle testing. During the ampacity testing of overhead conductors, the tester needs to observe the conductor temperature in real time, and adjust the output current in time, so as to reach the specified test temperature and keep it for a specified time, and then measure and record the conductor temperature, ambient temperature and test current at that time; after completing a test temperature point, repeat the above steps to test the ampacity of the next temperature point, until all required test temperatures are completed. This process requires the tester to record the temperature on the temperature patrol instrument at all times and adjust the output current at any time, the test period is long, the degree of automation is extremely low, and the test accuracy and reproducibility are poor.

[0003] In the thermal cycle test, the reference conductor temperature needs to be raised to a specified value within a specified time, and kept for a specified time, and then the temperature of the reference conductor and each test fitting is measured and recorded; then the power is turned off, the sample temperature is lowered to room temperature within a specified time, and kept for a specified time, and the above step is repeated until the specified number of cycles is reached. In this process, the tester needs to adjust the output current in real time according to the measured conductor temperature, and turn off the power after a specified period of time to cool down the sample. This process is repeated for a long period of time, during which the ambient temperature inevitably changes, and the adjustment of the test current is completely dependent on manual operation by the tester, resulting in low test accuracy, reproducibility, and low test efficiency, and requiring long-term personnel on duty. SUMMARY

[0004] In view of the above-mentioned shortcomings of the related art, the present application aims to provide an overhead cable testing device, ampacity testing method and thermal cycle testing method, to solve the problems of low test accuracy, poor reproducibility and low efficiency caused by manual operation by the tester in the conventional test method.

[0005] To achieve the above-mentioned objects and other related objects, the present application provides an overhead cable testing device, which comprises: two tensioning assemblies, which are oppositely arranged and can move away from each other, and are used to connect two ends of a measured cable and tension the measured cable; a power supply assembly, which is connected with the two tensioning assemblies, and is used to apply current to the measured cable; a temperature measuring assembly, which is used to measure the temperature of the measured cable and the ambient temperature at a specified distance from the measured cable; and a control assembly, which is electrically connected with the temperature measuring assembly and the power supply assembly, and is used to adjust the current output by the power supply assembly according to the measurement results of the temperature measuring assembly.

[0006] Optionally, the temperature measuring assembly comprises a first temperature measuring member and a second temperature measuring member, the first temperature measuring member is used to connect the measured cable, and the second temperature measuring member is arranged in the air at a set distance from the measured cable along the extension direction perpendicular to the measured cable.

[0007] Optionally, the number of the first temperature measuring members is at least three, and the plurality of first temperature measuring members are arranged at equal intervals along the extension direction of the measured cable.

[0008] Optionally, the tension assembly comprises an insulating member and a fixing member, the insulating member is rotationally connected with the fixing member, one end of the fixing member away from the insulating member is used to connect with the measured cable, and the fixing member is connected with the power supply assembly.

[0009] Optionally, the power supply assembly comprises a power supply and two current leading members, one end of the two current leading members is connected with the power supply, and the other end of the two current leading members is connected with the two fixing members respectively.

[0010] A current-carrying capacity test method, the steps of the overhead cable current-carrying capacity test method comprise:

[0011] Arranging a temperature measuring assembly at the measured cable and at a set distance from the measured cable;

[0012] Applying tension to the measured cable by the tension assembly to tension the measured cable;

[0013] Setting an initial current I0 and subsequent temperature points T1, T2, …, Tn in the control assembly i ;

[0014] The power supply assembly outputs the initial current I0, the temperature measuring assembly automatically monitors the temperature of the measured cable and the ambient temperature, after the temperature of the measured cable is stable, the control assembly records the initial current, the initial temperature of the measured cable and the initial ambient temperature;

[0015] According to the formula to estimate the current I1 required to be output by the power supply assembly at the T1 temperature, wherein the formula is:

[0016] T0 is the initial temperature of the measured cable, T a0 is the initial ambient temperature, T a1 is the ambient temperature when the current is I1;

[0017] The power supply assembly outputs the current I1, the temperature measuring assembly automatically monitors the temperature of the measured cable and the ambient temperature, and adjusts the output current I1 in real time according to the ambient temperature T a1 , after the temperature of the measured cable is stable, the control assembly records the output current, the temperature of the measured cable and the ambient temperature at this time;

[0018] If the temperature of the measured cable reaches the set value of the temperature point T1, the next temperature point test is performed, otherwise the above two steps are repeated to continue iteration.

[0019] Optionally, the temperature measuring assembly comprises a first temperature measuring member and a second temperature measuring member, and the step of arranging the temperature measuring assembly at the measured cable and at a distance from the measured cable comprises:

[0020] arranging the first temperature measuring member between the outer layer of the measured cable and the adjacent outer layer;

[0021] arranging the second temperature measuring member in the air at a distance from the measured cable.

[0022] Optionally, the tension assembly applies a tension of 10% of the rated breaking force to the measured cable.

[0023] Optionally, the condition for the temperature of the measured cable to be stable is that the temperature of the measured cable changes less than 0.5℃ within 30 minutes.

[0024] A thermal cycle test method, the steps of the overhead cable thermal cycle test method comprising:

[0025] arranging the temperature measuring assembly at the measured cable and at a distance from the measured cable;

[0026] applying a tension to the measured cable by the tension assembly to tension the measured cable;

[0027] arranging an initial current I0 and a target temperature T1 of the cycle test in the control assembly;

[0028] the power supply assembly outputs the initial current I0, the temperature measuring assembly automatically monitors the temperature of the measured cable and the ambient temperature, and after the temperature of the measured cable is stable, the control assembly records the initial current, the initial temperature of the measured cable and the initial ambient temperature;

[0029] estimating the current I1 required by the power supply assembly at the T1 temperature according to the formula, wherein the formula is:

[0030] T0 is the initial temperature of the measured cable, T a0 is the initial ambient temperature, T a1 is the ambient temperature when the current is I1;

[0031] the power supply assembly outputs the current I1, the temperature measuring assembly automatically monitors the temperature of the measured cable and the ambient temperature, and adjusts the output current I1 in real time according to the ambient temperature T a1 , and after the temperature of the measured cable is stable, the control assembly records the output current, the temperature of the measured cable and the ambient temperature at this time;

[0032] if the recorded temperature of the measured cable is less than the target temperature, repeat the above two steps until the temperature of the measured cable reaches the target temperature;

[0033] turn off the power supply assembly, and the measured cable naturally or forcibly cools down to room temperature;

[0034] Repeat the first four steps until the required number of cycles is reached.

[0035] As above, the overhead cable testing device, ampacity testing method and thermal cycle testing method of the present application have the following beneficial effects: solving the problems of traditional testing system requiring personnel on duty, manually adjusting output current, recording ambient temperature and sample temperature, poor test accuracy and poor repeatability. Effectively reducing the influence of human factors on test results, improving test accuracy and reproducibility, greatly improving test efficiency and reducing test cost. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The schematic diagram of the overhead cable testing device in the embodiment of the present application is shown.

[0037] Figure 2 The logic block diagram of the ampacity testing method in the embodiment of the present application is shown.

[0038] Figure 3 The logic block diagram of the thermal cycle testing method in the embodiment of the present application is shown.

[0039] ELEMENT NUMBER EXPLANATION

[0040] 1 Control assembly

[0041] 2 Insulating member

[0042] 3 Fixing member

[0043] 4 Power supply

[0044] 5 Drain wire

[0045] 6 Drain plate

[0046] 7 First temperature measuring member

[0047] 8 Second temperature measuring member

[0048] 9 Cable to be tested DETAILED DESCRIPTION

[0049] The embodiments of the present application are described below through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present specification. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the present specification based on different views and applications without departing from the spirit of the present application.

[0050] As in the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application here. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual production.

[0051] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the accompanying drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0052] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0053] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0054] like Figure 1 As shown, this embodiment provides an overhead cable testing device, which can automatically perform current carrying capacity tests, stranded wire linear expansion coefficient tests, and thermal cycling tests.

[0055] The overhead cable testing device includes two tensioning components, a power supply component, a temperature measurement component, and a control component 1. The two tensioning components are arranged opposite each other and can be kept away from each other. The two tensioning components are respectively connected to both ends of the cable under test 8 to tension the cable under test 8. For example, the tensioning components can be driven by a hydraulic cylinder or a motor.

[0056] The power supply assembly is connected to two tension assemblies for applying current to the cable under test 8 through the tension assemblies.

[0057] The temperature measurement component is used to measure the temperature of the cable under test 8 and the ambient temperature at a set distance from the cable under test 8.

[0058] Control component 1 is electrically connected to temperature measuring component and power supply component. Control component 1 is used to adjust the current output by power supply component according to the measurement result of temperature measuring component.

[0059] In the implementation process of the overhead cable testing device, two tension components apply tension to the measured cable 8 to tension the measured cable 8, and then the power component applies current to the measured cable 8, and after a period of time, the temperature of the measured cable 8 rises, and at this time, the temperature and environmental temperature changes of the measured cable 8 can be detected in real time under the monitoring of the temperature measuring component. The control component 1 can record the temperature and environmental temperature of the measured cable 8 detected by the temperature measuring component and send control instructions to the power component to adjust the current output by the power component. When the test personnel uses the overhead cable testing device to perform current-carrying capacity test or thermal cycle test, the control component 1 can automatically control the current output by the power component according to the temperature and environmental temperature of the measured cable 8 detected by the temperature measuring component, thereby avoiding the problem of low test accuracy caused by manual operation in the traditional way.

[0060] The tension component includes an insulating part 2 and a fixing part 3, the insulating part 2 is rotationally connected with the fixing part 3, one end of the fixing part 3 away from the insulating part 2 is used to connect with the measured cable 8, the fixing part 3 is connected with the power component, and the fixing part 3 is a strain clamp, the fixing part 3 is used to connect the measured cable 8 and conduct electricity to the measured cable 8. The insulating part 2 is used for insulation and is connected with an external power mechanism such as an oil cylinder or a motor.

[0061] The power component includes a power source 4 and two current leading parts, one end of each of the two current leading parts is connected to the power source 4, and the other end of each of the two current leading parts is connected with the two fixing parts 3. Specifically, the current leading part includes a current leading wire 5 and a current leading plate 6, one end of the current leading plate 6 is connected to the fixing part 3, the other end of the current leading plate 6 is connected with the current leading wire 5, the current leading plate 6 and the current leading wire 5 can be fixed by bolts, and one end of the current leading wire 5 away from the current leading plate 6 is connected with the power source 4. The current leading wire 5 and the current leading plate 6 are used to guide current to the measured cable 8.

[0062] The temperature measuring component includes a first temperature measuring part 7 and a second temperature measuring part 8, both of which are thermocouples, the first temperature measuring part 7 is connected to the measured cable 8, and the second temperature measuring part 8 is arranged in the air at a distance from the measured cable 8 along the vertical extension direction of the measured cable 8. Specifically, the first temperature measuring part 7 is inserted between the outer layer of the measured cable 8 and the adjacent outer layer, and the way of setting in this way will not change the external characteristics of the measured cable 8, thereby avoiding affecting the test results. In order to ensure the accuracy of detecting the temperature of the measured cable 8, the number of the first temperature measuring part 7 is at least three, the first first temperature measuring part 7 is arranged at the middle of the measured cable 8, the other two first temperature measuring parts 7 are arranged on both sides of the first first temperature measuring part 7, and the distance between the adjacent two first temperature measuring parts 7 is 100 cm.

[0063] The second temperature measuring element 8 is arranged in the air at a set distance from the first temperature measuring element 7 along the vertical extension direction of the cable 8, and is used to detect the ambient temperature. The set distance can be 100 cm.

[0064] The embodiment also provides an overhead cable ampacity test method, and steps of the overhead cable ampacity test method include:

[0065] The temperature measuring assembly is arranged at the cable 8 and at a set distance from the cable 8.

[0066] The tension assembly is used to apply tension to the cable 8 to tension the cable 8.

[0067] The initial current I0 and subsequent temperature points T1, T2, …, T i are set in the control assembly 1.

[0068] The power supply assembly outputs the initial current I0, and the temperature measuring assembly automatically monitors the temperature of the cable 8 and the ambient temperature. After the temperature of the cable 8 is stable, the control assembly 1 records the initial current, the initial temperature of the cable 8 and the initial ambient temperature.

[0069] The current I1 required by the power supply assembly at the temperature T1 is estimated according to the formula, where the formula is:

[0070] T0 is the initial temperature of the cable 8, T a0 is the initial ambient temperature, and T a1 is the ambient temperature when the current is I1.

[0071] The power supply assembly outputs the current I1, and the temperature measuring assembly automatically monitors the temperature of the cable 8 and the ambient temperature, and adjusts the output current I1 in real time according to the ambient temperature T a1 . After the temperature of the cable 8 is stable, the control assembly 1 records the output current, the temperature of the cable 8 and the ambient temperature.

[0072] If the temperature of the cable 8 reaches the set value of the temperature point T1, the next temperature point test is performed, otherwise the above two steps are repeated to continue iteration.

[0073] Specifically, after the temperature measuring assembly is arranged, the two tension assemblies are forced to tension the cable 8, and the tension assembly applies tension to the cable 8 at 10% of the rated breaking force. Then the initial current I0 output and the subsequent test temperature points T1, T2, …, T iThe temperature of the measured cable 8 gradually rises at the beginning of the experiment, and when the temperature of the measured cable 8 stabilizes after a period of time, the temperature of the measured cable 8 stabilizes under the condition that the temperature of the measured cable 8 changes less than 0.5℃ within 30 minutes, and the control assembly 1 records the initial current, the initial temperature of the measured cable 8 and the initial ambient temperature at this time. For example, when the initial current is 800 amperes, the initial temperature of the measured cable 8 recorded after the temperature of the measured cable 8 stabilizes is 30℃, and the initial ambient temperature T a0 is 20℃. Then the value of I1 is calculated according to the formula, wherein the temperature T1 value in the formula is a preset value, for example, 50℃, and the ambient temperature T a1 is considered to remain unchanged, still 20℃, at this time, I1 can be calculated according to the formula. The power assembly passes the current I1 to the measured cable 8, and when the temperature of the measured cable 8 stabilizes at 50℃, the temperature point T1 test operation is completed, and then the above steps are repeated to calculate the value of I2 and output I2 to continue the test. If the power assembly passes the current I1 to the measured cable 8, and when the temperature of the measured cable 8 stabilizes at 48 degrees, the temperature is iterated into the formula, at this time, T0 = 48, T a0 = 20, T1 = 50, T a1 = 20, the current I1 output by the formula is continued to be calculated and the new current value I1 calculated is output to the measured cable 8 again, and when the temperature of the measured cable 8 stabilizes at 50℃, the temperature point T1 test operation is completed, otherwise the iteration is continued. Through repeating the above steps, all temperature points are tested, and finally a graph is drawn according to the needs, for example, a current-temperature curve of the current-carrying capacity test.

[0074] The step of arranging the temperature measuring assembly at the measured cable 8 and at a set distance from the measured cable 8 includes:

[0075] The first temperature measuring member 7 is arranged between the outer layer and the adjacent outer layer of the measured cable 8;

[0076] The second temperature measuring member 8 is arranged in the air at a set distance from the measured cable 8.

[0077] It should be noted that during the test, an air conditioner is arranged in the test site, and the room temperature basically remains unchanged. Since the measured cable 8 will dissipate heat, when the room temperature fluctuates, the second temperature measuring member 8 inputs the real-time detected ambient temperature into the control assembly 1, and the control assembly 1 automatically calculates a new current I1 according to the new ambient temperature and outputs the adjusted current I1. Since the second temperature measuring member 8 can detect the ambient temperature in real time, the control assembly 1 can adjust the output current I1 at any time according to the ambient temperature, thereby improving the accuracy and precision of the test.

[0078] The embodiment also provides a thermal cycle test method, and steps of the overhead cable thermal cycle test method include:

[0079] The temperature measuring assembly is arranged at the measured cable 8 and a position with a set distance from the measured cable 8;

[0080] The tension assembly is used to apply tension to the measured cable 8 to tension the measured cable 8;

[0081] The initial current I0 and the target temperature T1 of the cycle test are set in the control assembly 1;

[0082] The power supply assembly outputs the initial current I0, the temperature measuring assembly automatically monitors the temperature of the measured cable 8 and the ambient temperature, and after the temperature of the measured cable 8 is stable, the control assembly 1 records the initial current, the initial temperature of the measured cable 8 and the initial ambient temperature;

[0083] The current I1 required by the power supply assembly at the T1 temperature is estimated according to the formula, wherein the formula is:

[0084] T0 is the initial temperature of the measured cable 8, T a0 is the initial ambient temperature, T a1 is the ambient temperature when the current is I1;

[0085] The power supply assembly outputs the current I1, the temperature measuring assembly automatically monitors the temperature of the measured cable 8 and the ambient temperature, and adjusts the output current I1 in real time according to the ambient temperature T a1 , and after the temperature of the measured cable 8 is stable, the control assembly 1 records the current, the temperature of the measured cable 8 and the ambient temperature at this time;

[0086] If the recorded temperature of the measured cable 8 is less than the target temperature, the above two steps are repeated until the temperature of the measured cable 8 reaches the target temperature;

[0087] The power supply assembly is turned off, and the measured cable 8 is naturally or forcibly cooled to room temperature;

[0088] The above four steps are repeated until the cycle number requirement is met.

[0089] Specifically, when the temperature measuring assembly is arranged, the two tension assemblies are applied force to tension the measured cable 8, and the tension assembly applies tension to the measured cable 8 at 10% of the rated breaking force. Then, the initial output current I0 and the target temperature T1 of the cycle test are set in the control assembly 1. At the beginning of the test, the power supply assembly first outputs the initial current, and the temperature of the measured cable 8 gradually rises. When the temperature of the measured cable 8 is stable after a period of time, the condition for the temperature of the measured cable 8 to be stable is that the temperature change of the measured cable 8 is less than 0.5°C within 30 minutes, and the control assembly 1 records the initial current, the initial temperature of the measured cable 8, and the initial ambient temperature at this time. For example, when the initial current is 800 amperes, the initial temperature of the measured cable 8 recorded after the temperature of the measured cable 8 is stable is 30°C, and the initial ambient temperature T a0 is 20°C. Then, the value of I1 is calculated according to the formula, wherein the value of the temperature T1 in the formula is a pre-set value, for example, 100°C, and the ambient temperature T a1 is considered to remain unchanged, and is still 20°C. At this time, I1 can be calculated according to the formula. The power supply assembly inputs the current I1 to the measured cable 8, and when the temperature of the measured cable 8 is stable at 100°C, one cycle of the test operation is completed. Then, when the temperature of the measured cable 8 drops to room temperature, the above operation is repeated until the required number of cycles is reached. If the power supply assembly inputs the current I1 to the measured cable 8, and when the temperature of the measured cable 8 is stable, the temperature of the measured cable 8 is 90°C. At this time, T0 = 90, T a0 = 20, T1 = 100, and T a1 = 20 in the formula, the output current I1 is calculated according to the formula, and the calculated new current value I1 is output to the measured cable 8 again. If the temperature of the measured cable 8 is stable at 100°C when the cycle test is completed, otherwise the iteration is continued until the temperature of the measured cable 8 is 100°C. By repeating the above four steps until the required number of cycles is reached, the graph, for example, the temperature-time curve of the cycle test, is finally drawn according to the needs.

[0090] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. An overhead cable testing device, characterized in that, include: Two tension components are arranged opposite each other and can be far apart from each other. The two tension components are used to connect the two ends of the cable under test and tension the cable under test. A power supply assembly, connected to the two tension assemblies, is used to apply current to the cable under test; A temperature measurement component, which is used to measure the temperature of the cable under test and the ambient temperature at a set distance from the cable under test; A control component is electrically connected to the temperature sensing component and the power supply component. The control component is used to adjust the current output by the power supply component based on the measurement result of the temperature sensing component.

2. The overhead cable testing device according to claim 1, characterized in that: The temperature measurement component includes a first temperature measuring element and a second temperature measuring element. The first temperature measuring element is used to connect to the cable under test, and the second temperature measuring element is disposed in the air at a set distance from the cable under test along the extension direction perpendicular to the cable under test.

3. The overhead cable testing device according to claim 2, characterized in that: The number of the first temperature measuring elements is at least three, and multiple first temperature measuring elements are arranged at equal intervals along the extension direction of the cable under test.

4. The overhead cable testing device according to claim 1, characterized in that: The tension assembly includes an insulating component and a fixing component. The insulating component is rotatably connected to the fixing component. The end of the fixing component away from the insulating component is used to connect to the cable under test. The fixing component is connected to the power supply assembly.

5. The overhead cable testing device according to claim 4, characterized in that: The power supply assembly includes a power source and two drain elements. One end of each drain element is connected to the power source, and the other end of each drain element is connected to one of the two fixing elements.

6. A method for testing the current carrying capacity of an overhead cable using the overhead cable testing apparatus as described in any one of claims 1-5, characterized in that: The steps of the current carrying capacity test method include: Temperature measurement components are installed on the cable under test and at a set distance from the cable under test. Tension is applied to the cable under test using a tension assembly to tighten the cable under test; Set the initial current I0 and the subsequent temperature points T1, T2, ... T within the control component. i ; The power supply component outputs an initial current I0, and the temperature measurement component automatically monitors the temperature of the cable under test and the ambient temperature. After the temperature of the cable under test stabilizes, the control component records the initial current, the initial temperature of the cable under test, and the initial ambient temperature. Estimate the required output current I1 of the power supply component at temperature T1 using the formula: T0 is the initial temperature of the cable being measured, T a0 The initial ambient temperature, T a1 The ambient temperature is when the current is I1; The power supply component outputs current I1, and the temperature sensing component automatically monitors the temperature of the cable under test and the ambient temperature, and adjusts the readings in real time based on the ambient temperature T. a1 Adjust the output current I1, and after the temperature of the cable under test stabilizes, the control component records the output current, the temperature of the cable under test, and the ambient temperature at this time. If the temperature of the cable under test reaches the set value of temperature point T1, then proceed to the next temperature point test; otherwise, repeat the above two steps to continue the iteration.

7. The current carrying capacity test method according to claim 6, characterized in that: The temperature measuring component includes a first temperature measuring element and a second temperature measuring element. The step of deploying the temperature measuring component at the cable under test and at a predetermined distance from the cable under test includes: The first temperature sensor is placed between the outer layer of the cable being tested and the adjacent outer layer. The second temperature sensor is placed in the air at a set distance from the cable being tested.

8. The current carrying capacity test method according to claim 6, characterized in that: The tension assembly applies a tension of 10% of the rated breaking force to the cable under test.

9. The current carrying capacity test method according to claim 6, characterized in that: The condition for stable temperature of the tested cable is: the temperature change of the tested cable is less than 0.5℃ within 30 minutes.

10. A thermal cycling test method using the overhead cable testing apparatus according to any one of claims 1-5, characterized in that: The steps of the thermal cycling test method include: Temperature measurement components are installed on the cable under test and at a set distance from the cable under test. Tension is applied to the cable under test using a tension assembly to tighten the cable under test; Set the initial current I0 and the target temperature T1 for the cyclic test within the control component; The power supply component outputs an initial current I0, and the temperature measurement component automatically monitors the temperature of the cable under test and the ambient temperature. After the temperature of the cable under test stabilizes, the control component records the initial current, the initial temperature of the cable under test, and the initial ambient temperature. Estimate the required output current I1 of the power supply component at temperature T1 using the formula: T0 is the initial temperature of the cable being measured, T a0 The initial ambient temperature, T a1 The ambient temperature is when the current is I1; The power supply component outputs current I1, and the temperature sensing component automatically monitors the temperature of the cable under test and the ambient temperature, and adjusts the readings in real time based on the ambient temperature T. a1 Adjust the output current I1, and after the temperature of the cable under test stabilizes, the control component records the output current, the temperature of the cable under test, and the ambient temperature at this time. If the recorded temperature of the tested cable is lower than the target temperature, repeat the above two steps until the temperature of the tested cable reaches the target temperature. The power supply is turned off, and the cable under test cools down to room temperature naturally or under forced cooling. Repeat the first four steps until the required number of iterations is reached.

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