Method and device for detecting thermal damage of overhead line

Abstract

The invention provides an overhead line thermal damage detection method and device, and the method comprises the steps: obtaining the resistance of a to-be-detected system, and an experiment platform comprises the to-be-detected system and an excitation module which are connected; controlling the excitation module to apply processing frequency current to the to-be-tested system so as to obtain a first duration when the temperature of the to-be-tested system reaches a preset temperature and a second duration when the temperature sensing device acts; first heat and second heat are determined at least according to the resistance, the first heat is heat generated when the temperature of the to-be-tested system reaches a preset temperature, and the second heat is heat generated by the to-be-tested system when the temperature sensing device acts; judging whether the action of the temperature sensing device meets the accuracy requirement or not according to the first heat and the second heat; and under the condition that the action of the temperature sensing device meets the accuracy requirement, the temperature sensing device is adopted to detect the thermal damage of the overhead line. The problem that in the prior art, the thermal defect detection precision of an overhead line is insufficient is at least solved.

Description

Technical Field

[0001] The present application relates to the field of detection of thermal damage to overhead lines, and in particular, to a method and device for detecting thermal damage to overhead lines. Background Art

[0002] Among power grid operation failures, overhead ground wire breakage due to lightning strike is one of the most common permanent faults. Although overhead ground wire is the most basic and effective lightning protection measure for high-voltage transmission lines, it also has the risk of breaking and falling when struck by lightning. Generally speaking, it is rare for a single lightning strike to directly cause a line break. There are often multiple lightning strikes that cause broken strands. It is a development process from broken strand damage to line breakage. It is necessary to detect broken strand damage in time to avoid line breakage. Once a line break occurs, the protection of the equipment will be lost, which may cause damage to the equipment, easily cause multi-tower chain accidents, and pose a huge threat to the surrounding environment. Therefore, timely detection and handling of potential line break hazards are extremely important for the stable operation of the power grid and the safety of people's lives and property.

[0003] As an important line of defense for lightning protection of high-voltage transmission lines, the ground wire is installed above the transmission line through the suspension wire clamp. When lightning strikes the overhead ground wire, it will be injected into the earth along the path of ground wire-suspension wire clamp-tower. If struck by lightning for a long time, the overhead ground wire and the suspension wire clamp will suffer thermal damage. The damaged gap may corrode in the environment of wind, sun and rain, further lose mechanical strength, and also pose a safety hazard. Therefore, it is imperative to detect thermal damage and thermal defects in the suspension wire clamp.

[0004] In the current power grid system, the main methods for checking thermal defects and thermal damage of overhead lines are infrared temperature measurement and infrared thermal imaging technology. These two types of infrared detection technologies can truly and efficiently predict and speculate the initial fault deviation and insulation conditions of electrical facilities, allowing the inspection and maintenance of electrical facilities to develop from defensive maintenance to predictive maintenance. In addition, during the use process, it can also be done without connection, power off, or disassembly, and has achieved efficient development. However, it also has great limitations, such as limited measurement range, low measurement accuracy, and greater environmental impact.

[0005] The existing technology can adopt a variety of experimental methods, but all of them have shortcomings that are difficult to solve. One method is to use lightning current to directly excite the sample on the experimental platform, but the existing excitation device cannot fully simulate the lightning current, and the lightning current energy is huge, which poses a great safety hazard. Another method is to use the finite element simulation experimental method, but this method cannot fully simulate the actual situation, and requires quantitative processing of the parameters of the experimental platform, the data is complicated, and the amount of calculation is large. The platform is difficult to build, and the adjustability of the structural parameters, boundary conditions, and excitation settings is poor, which requires a lot of time and effort. Another method is to use a constant temperature box experimental method. The disadvantage is that the physical process in the constant temperature box is far different from the physical process during the actual lightning strike, and it will produce a large error compared to the short-term high temperature of the lightning strike. Summary of the invention

[0006] The main purpose of the present application is to provide a method and device for detecting thermal damage of overhead lines, so as to at least solve the problem of insufficient accuracy in detecting thermal defects of overhead lines in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for detecting thermal damage of an overhead line is provided, comprising: obtaining the resistance of a system to be tested, wherein an experimental platform comprises the system to be tested and an excitation module connected thereto, the system to be tested comprising a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connecting the temperature sensing device and the component to be tested; controlling the excitation module to apply an industrial frequency current to the system to be tested, so as to obtain a first time duration for the temperature of the system to be tested to reach a preset temperature and a second time duration for the temperature sensing device to take action; determining a first amount of heat and a second amount of heat at least based on the resistance, wherein the first amount of heat is the heat generated when the temperature of the system to be tested reaches the preset temperature, and the second amount of heat is the heat generated by the system to be tested when the temperature sensing device takes action; judging whether the action of the temperature sensing device meets the accuracy requirement based on the first amount of heat and the second amount of heat; and using the temperature sensing device to detect thermal damage to the overhead line when the action of the temperature sensing device meets the accuracy requirement.

[0008] Optionally, determining the first amount of heat and the second amount of heat at least according to the resistance includes: according to the resistance and a first formula: The first heat Q1 is obtained, where I0 is the power frequency current, R 总 is the resistance, t1 is the first time duration; according to the resistance and the second formula: The second heat Q2 is obtained, wherein t2 is the second time duration.

[0009] Optionally, judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount includes: judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount, the second heat amount and a third formula: A relative error σ is obtained; and a magnitude relationship between the relative error σ and a first threshold is determined; when the relative error σ is less than the first threshold, the action of the temperature sensing device meets the accuracy requirement.

[0010] Optionally, the method also includes: determining a third heat at least based on the resistance, the third heat being the heat generated by the system to be tested when the lightning current passes through the temperature sensing device; determining a fourth heat at least based on the first duration, the fourth heat being the heat generated by the system to be tested when the power frequency current passes through the temperature sensing device; and verifying whether the experimental platform meets the rationality requirements based on the third heat and the fourth heat.

[0011] Optionally, determining the third heat at least based on the resistance includes: determining a fifth heat based on the resistance and Joule's law, wherein the fifth heat is the heat generated by the lightning current flowing through the system to be measured; determining a sixth heat based on the resistance and a Gaussian heat source model, wherein the sixth heat is the heat generated by a local breakdown of the system to be measured; determining the third heat based on the fifth heat and the sixth heat, wherein the third heat is the sum of the fifth heat and the sixth heat.

[0012] Optionally, determining the fifth amount of heat according to the resistance and Joule's law includes: according to the resistance and a fourth formula: Get the heat Q generated by the pilot current A , where I p is the magnitude of the pilot current, R 总 is the resistance, α is the wave front time of the lightning current, β is the half-peak time of the lightning current, t is the action time of the pilot current, t3 is the total action time of the pilot current, wherein the lightning current includes the pilot current and the continuous current; according to the resistance and the fifth formula: The heat Q generated by the continuous current is obtained C , where I C is the continuous current, t4 is the total action time of the continuous current; according to the heat Q A and the heat Q C , obtain the fifth heat, wherein the fifth heat is the heat Q A and the heat Q C sum.

[0013] Optionally, determining the fourth amount of heat at least based on the first duration includes: obtaining the first temperature, the second temperature and the third temperature of the pressure plate, wherein the pressure plate has a first surface and a second surface, the first surface is in contact with the element to be measured, the second surface is in contact with the air, the first temperature is the temperature of the first surface, the second temperature is the temperature of the second surface, and the third temperature is the temperature of the air; determining the seventh amount of heat based on the first duration, the first temperature, the second temperature and the third temperature; determining the fourth amount of heat based on the first amount of heat and the seventh amount of heat, wherein the fourth amount of heat is the difference between the first amount of heat and the seventh amount of heat.

[0014] Optionally, determining a seventh amount of heat according to the first temperature, the second temperature, and the third temperature includes: determining a seventh amount of heat according to the first temperature, the second temperature, and a sixth formula: The first heat loss amount q1 is obtained, wherein λ is the thermal conductivity of the material of the pressure plate, A1 is the contact surface area between the pressure plate and the element to be measured, S is the thickness of the pressure plate, and ΔT1 is the difference between the first temperature and the second temperature; according to the second temperature, the third temperature and the seventh formula: q2=aA2ΔT2, the second heat loss amount q2 is obtained, wherein a is the convection heat transfer coefficient, A2 is the contact area between the pressure plate and the air, and ΔT2 is the difference between the second temperature and the third temperature; according to the first time length and the eighth formula: Q4=(q1+q2)t1, the seventh heat amount Q4 is obtained, wherein t1 is the first time length.

[0015] Optionally, based on the third heat and the fourth heat, checking whether the experimental platform meets the rationality requirement includes: judging the size relationship between a first difference and a second threshold, the first difference being the absolute value of the difference between the third heat and the fourth heat; when the first difference is less than the second threshold, the experimental platform meets the rationality requirement.

[0016] According to another aspect of the present application, a device for detecting thermal damage of an overhead line is provided, comprising: a first acquisition unit, for acquiring the resistance of a system to be tested, wherein an experimental platform comprises the system to be tested and an excitation module connected thereto, the system to be tested comprising a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connecting the temperature sensing device and the component to be tested; a control unit, for controlling the excitation module to apply an industrial frequency current to the system to be tested, so as to obtain a first time duration for the temperature of the system to be tested to reach a preset temperature and a second time duration for the temperature sensing device to take action; a determination unit, for determining a first amount of heat and a second amount of heat based at least on the resistance, wherein the first amount of heat is the heat generated when the temperature of the system to be tested reaches the preset temperature, and judging whether the action of the temperature sensing device meets the accuracy requirement; a judgment unit, for judging whether the action of the temperature sensing device meets the accuracy requirement based on the first amount of heat and the second amount of heat; and a detection unit, for detecting the thermal damage of the overhead line using the temperature sensing device when the action of the temperature sensing device meets the accuracy requirement.

[0017] By applying the technical solution of the present application, the accuracy and reliability of the action of the temperature sensing device are tested through the construction of an experimental platform to overcome the shortcomings of the experimental method for thermal damage of overhead lines in the power grid system in the prior art, wherein the experimental platform includes the connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connects the temperature sensing device and the component to be tested, and obtains the resistance of the system to be tested to increase the accuracy of the detection; the excitation module is controlled to apply an industrial frequency current to the system to be tested to obtain a first time duration for the temperature of the system to be tested to reach a preset temperature and a second time duration for the temperature sensing device to be activated, and by using the industrial frequency current as the excitation current, the physical action process of the lightning current can be equivalent, and its current path is the same as the lightning current path, and the heat generated at the temperature sensing part during the action of the lightning current can be equivalent, thereby avoiding the high cost and harshness caused by the artificial lightning induction method. conditions, reducing the danger of artificial drainage; at least according to the resistance, determine the first heat and the second heat, wherein the first heat is the heat generated when the temperature of the system to be tested reaches the preset temperature, and the second heat is the heat generated by the system to be tested when the temperature sensing device is activated. According to the first heat and the second heat, judge whether the action of the temperature sensing device meets the accuracy requirements, use the power frequency current as the current excitation, compare and analyze the heat generated when the device reaches the action temperature and the heat generated when the device is activated, and verify the accuracy of the action temperature design of the core temperature sensing element; when the action of the temperature sensing device meets the accuracy requirements, use the temperature sensing device to detect the thermal damage of the overhead line, and use the temperature sensing device that meets the accuracy to detect the thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection. The heat equivalent experimental method using the power frequency current as the excitation can be equivalent to the physical action process of the lightning current, and its current path is the same as the lightning current path, and it can be equivalent to the heat generated by the temperature sensing part during the action of the lightning current. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 A hardware structure block diagram of a mobile terminal for executing a method for detecting thermal damage of an overhead line provided in an embodiment of the present application is shown;

[0020] Figure 2 A schematic flow chart of a method for detecting thermal damage of an overhead line provided according to an embodiment of the present application is shown;

[0021] Figure 3A structural diagram of a component to be tested provided according to an embodiment of the present application is shown;

[0022] Figure 4 The structure diagram of the temperature sensing device and the pressure plate provided according to the embodiment of the present application is shown;

[0023] Figure 5 A structural diagram of another temperature sensing device provided according to an embodiment of the present application is shown;

[0024] Figure 6 A structural diagram of a temperature sensing device structure when a lever lock is unlocked according to an embodiment of the present application is shown;

[0025] Figure 7 A structural diagram of a temperature sensing device according to an embodiment of the present application is shown when a lever lock is out of a slot;

[0026] Figure 8 A structural block diagram of a device for detecting thermal damage of an overhead line provided according to an embodiment of the present application is shown.

[0027] The above drawings include the following reference numerals:

[0028] 102. Processor; 104. Memory; 106. Transmission equipment; 108. Input / output equipment; 301. Ground wire; 302. Aluminum tape; 303. Pressure plate; 304. Hanging plate; 305. Current circuit; 306. Temperature sensing device; 401. Bimetallic strip; 402. Lever lock; 403. Spring; 404. Metal jacket; 4041. Upper metal sleeve; 4042. Lower metal sleeve; 405. Red warning light. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] As introduced in the background technology, a variety of experimental methods can be used in the prior art to detect thermal damage of overhead lines, but all of them have shortcomings that are difficult to solve. One method is to use lightning current to directly excite the sample on the experimental platform, but the existing excitation device cannot completely simulate the lightning current, and the lightning current energy is huge, which poses a great safety hazard. Another method is to use the experimental method of finite element simulation, but this method cannot completely simulate the actual situation, and requires quantitative processing of the parameters of the experimental platform, the data is complicated, and the amount of calculation is large. The platform is difficult to build, and the adjustability of the structural parameters, boundary conditions, and excitation settings is poor, which requires a lot of time and effort. Another method is to use a constant temperature box experimental method. The disadvantage is that the physical process in the constant temperature box is very different from the physical process during the actual lightning strike, and it will produce a large error compared with the short-term high temperature of the lightning strike. In order to solve the above technical problems, the embodiments of the present application provide a method and device for detecting thermal damage of overhead lines.

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0034] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1 FIG. 1 is a hardware structure block diagram of a mobile terminal of a method for detecting thermal damage of an overhead line according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0035] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the method for detecting thermal damage of overhead lines in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the mobile terminal via a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof. The transmission device 106 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0036] In this embodiment, a method for detecting thermal damage of overhead lines running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0037] Specifically, the existing patent designs an intelligent passive detection device for short-term high temperature of suspension clamps based on finite element simulation method, as shown in the figure below. The detection device uses a thermal bimetallic strip as the core temperature sensing element to achieve rapid detection of the transient process of abnormal temperature rise caused by lightning current acting on the suspension clamp. The mechanism of action of the device is: according to the characteristics of the bimetallic strip, the two layers of metal expand to different degrees when heated, the bimetallic strip bends to unlock the lever lock, and the spring action pops out the alarm. After the fault is eliminated, the alarm can be reset and used again. For the design of the device action temperature, the patent uses the finite element simulation method to simulate and model the short-term high temperature of lightning strikes, including establishing a geometric model of the ground wire-clip assembly wrapped with aluminum tape, setting material physical properties and model boundary conditions. According to the simulation results of short-term high temperature of lightning strikes and the calculation and analysis of the degree of attenuation of the tensile strength of the overhead ground wire with temperature, combined with the ambient temperature value of long-term outdoor operation in summer, the corresponding action temperature value, that is, the temperature sensing action threshold, can be selected.

[0038] Now we need to use an experimental method to verify that the designed intelligent passive detection device is suitable for practical application and can achieve the expected results of detecting short-term high-temperature thermal defects. As can be seen from the above, the core component of the intelligent passive detection device is the temperature sensing element, so we only need to design an experimental method to calibrate the temperature sensing element and verify the accuracy and reliability of its action. There are many ways to achieve the experimental purpose, but they all have shortcomings:

[0039] Method 1 is to use an impulse current generator to build a lightning current simulation experimental platform, but the existing excitation device can only be used to simulate the damage caused by direct lightning current, and cannot simulate the damage caused by the lightning current being injected into the ground wire and flowing through the wire clamp.

[0040] Method 2 uses artificial lightning induction methods. Although it can restore the actual physical scene, it is expensive on the one hand, and can only be tested outdoors during thunderstorm season, under harsh conditions on the other hand.

[0041] The third method is to use the finite element simulation experimental method, but this method cannot fully simulate the actual situation, especially the need to quantify the parameters of the experimental platform, the amount of calculation is large, and the adjustability of structural parameters, boundary conditions, and excitation settings is poor.

[0042] Method 4 uses a constant temperature box experimental method. The disadvantage is that the constant temperature box mainly uses air for heat transfer. The process of causing the temperature change of the sample in the box is very different from the physical process of causing the temperature change in the wire clamp during an actual lightning strike. Compared with the short-term high temperature condition of a lightning strike, a large error will occur.

[0043] Figure 2 FIG. 1 is a flow chart of a method for detecting thermal damage to overhead lines according to an embodiment of the present application. Figure 2 As shown, the method comprises the following steps:

[0044] Step S201, obtaining the resistance of the system to be tested, wherein the experimental platform includes the system to be tested and an excitation module connected, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, and the pressure plate connects the temperature sensing device and the component to be tested.

[0045] Specifically, the resistance of the system to be tested can be obtained by a black box experiment, that is, the components corresponding to the resistance are regarded as a whole, and the corresponding value can be calculated after the response is measured by adding an external stimulus. The black box experiment can be completed by existing impedance measuring instruments, bridge method resistance measurement and other means. The calculation of heat through the resistance of the component to be tested not only simplifies the experimental platform, but also increases the accuracy of the detection.

[0046] Step S202 , controlling the excitation module to apply a power frequency current to the system to be measured, so as to obtain a first time duration for the temperature of the system to be measured to reach a preset temperature and a second time duration for the temperature sensing device to be actuated.

[0047] Specifically, industrial frequency current refers to the frequency of city electricity (industrial electricity), which is a type of alternating current with a lower frequency, usually 50 Hz or 60 Hz. The frequency and waveform of industrial frequency current are stable, which is conducive to the stable operation of the power system and the normal operation of equipment. The thermal equivalent experimental method using industrial frequency current as excitation can be equivalent to the physical action process of lightning current. Its current path is the same as that of lightning current, avoiding the high cost and harsh conditions caused by artificial lightning induction methods, and reducing the dangers brought by artificial induction.

[0048] Step S203, determining a first heat amount and a second heat amount at least based on the resistance, wherein the first heat amount is the heat generated when the temperature of the system under test reaches a preset temperature, and the second heat amount is the heat generated by the system under test when the temperature sensing device is actuated.

[0049] Specifically, an experimental platform is established with power frequency current as the excitation and the suspension wire clamp-ground wire system as the excitation object. The ground wire, the contact resistance of the ground wire and the aluminum tape, and the aluminum tape are all incorporated into the current loop. The experiment is conducted on this experimental platform. Under the power frequency current excitation, the heat generated by the system to be tested to reach the designed action temperature is the first heat, and the heat generated by the part to make the temperature sensing device act under the power frequency current is the second heat. The heat obtained by the theoretical system reaching the action temperature and the actual temperature sensing device reaching the action is simplified, the experimental process is reduced, the experimental cost is convenient to operate, and the safety factor is high.

[0050] Step S204: judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount.

[0051] Specifically, the first heat and the second heat obtained under the experimental method are set within a specified error range so that the error of the temperature sensing device is within a controllable range. In addition, the error setting can also be adjusted according to user needs, thereby accurately and reliably judging whether the action temperature setting of the temperature sensing device meets the needs, thereby improving the user experience.

[0052] Step S205: When the action of the temperature sensing device meets the accuracy requirement, the temperature sensing device is used to detect the thermal damage of the overhead line.

[0053] Specifically, using industrial frequency current as current excitation, the heat generated when the device reaches the operating temperature and the heat generated when the device is operated are compared and analyzed to verify the accuracy of the operating temperature design of the core temperature sensing element; when the action of the temperature sensing device meets the accuracy requirements, the temperature sensing device is used to detect thermal damage to the overhead line. The temperature sensing device that meets the accuracy requirements is used to detect thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection.

[0054] Through this embodiment, the accuracy and reliability of the action of the temperature sensing device are tested through the constructed experimental platform to overcome the shortcomings of the experimental method for thermal damage of overhead lines in the power grid system in the prior art, wherein the experimental platform includes a connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connects the temperature sensing device and the component to be tested, and the resistance of the system to be tested is obtained to increase the accuracy of the detection; the excitation module is controlled to apply an industrial frequency current to the system to be tested to obtain the first time duration for the temperature of the system to be tested to reach a preset temperature and the second time duration for the temperature sensing device to be activated, and the industrial frequency current is used as the excitation current to be equivalent to the physical action process of the lightning current, and its current path is the same as the lightning current path, and the heat generated at the temperature sensing part during the action of the lightning current can be equivalent, thereby avoiding the high cost caused by the artificial lightning induction method. This and harsh conditions, reduce the danger brought by artificial drainage; at least according to the resistance, determine the first heat and the second heat, wherein the first heat is the heat generated when the temperature of the system to be tested reaches the preset temperature, and the second heat is the heat generated by the system to be tested when the temperature sensing device is activated. According to the first heat and the second heat, judge whether the action of the temperature sensing device meets the accuracy requirements, use the power frequency current as the current excitation, compare and analyze the heat generated when the device reaches the action temperature and the heat generated when the device is activated, and verify the accuracy of the action temperature design of the core temperature sensing element; when the action of the temperature sensing device meets the accuracy requirements, use the temperature sensing device to detect the thermal damage of the overhead line, and use the temperature sensing device that meets the accuracy to detect the thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection. The heat equivalent experimental method using the power frequency current as the excitation can be equivalent to the physical action process of the lightning current. Its current path is the same as the lightning current path, and it can be equivalent to the heat generated by the temperature sensing part during the action of the lightning current. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor.

[0055] The prior art can adopt a variety of experimental methods, but all of them have shortcomings that are difficult to solve. One method is to use lightning current to directly excite the sample on the experimental platform, but the existing excitation device cannot completely simulate the lightning current, and the lightning current energy is huge, which poses a great safety hazard. Another method is to use the experimental method of finite element simulation, but this method cannot completely simulate the actual situation, and it is necessary to quantify the parameters of the experimental platform, the data is complicated, and the amount of calculation is large. The platform is difficult to build, and the adjustability of the structural parameters, boundary conditions, and excitation settings is poor, which requires a lot of time and effort. Another method is to use the experimental method of a constant temperature box. The disadvantage is that the physical process in the constant temperature box is far different from the physical process during the actual lightning strike, and a large error will be generated compared with the short-term high temperature of the lightning strike. In view of these shortcomings, the heat equivalent experimental method proposed in this patent with power frequency current as the excitation can be equivalent to the physical action process of the lightning current. Its current path is the same as the lightning current path, and it can be equivalent to the heat generated by the temperature sensing part during the lightning current action process. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor.

[0056] The geometric model of the above experimental platform includes the system to be tested, that is, the sample of the suspension clamp-ground wire system such as Figure 3 As shown, it includes a ground wire 301 , an aluminum tape 302 , a pressing plate 303 , a hanging plate 304 and a current line 305 .

[0057] The experimental platform also includes a section of wire strand, a section of aluminum tape, a suspension wire clamp, a set of temperature sensing action devices, a large current generator, a thermocouple temperature measuring device and a bracket for fixing.

[0058] Among them, the current excitation source is a large current generator, which is connected to the experimental sample through a large-section copper wire that allows hundreds of amperes of current to flow. One end of the copper wire is connected to the wire strand, and the other end is connected to the suspension wire clamp hanging plate, that is, the position of the ground wire 301 and the hanging plate 304. The large current generator is divided into two parts: a generating circuit and a control circuit. The generating circuit consists of a 220V AC power supply, a voltage regulator, and a step-down transformer with a fixed transformation ratio. The voltage regulator is powered by a 220V AC power supply, and the voltage regulator powers the step-down transformer. The secondary side of the step-down transformer is used as a large current output port to achieve the purpose of amplifying the current. The control circuit is used to control the action of the paddle of the voltage regulator. By adjusting the paddle, the voltage delivered by the voltage regulator to the primary side of the step-down transformer is changed, thereby controlling the output voltage and current of the secondary side of the step-down transformer to achieve the purpose of regulating the current. The excitation object is built using experimental materials such as Figure 3 The temperature sensing device is installed at the position of the pressure plate 303, as shown in the sample of the suspension wire clamp-ground wire system. Figure 4 The thermocouple temperature measuring device is laid on the contact surface between the pressing plate 303 and the temperature sensing device 306 and the contact surface between the pressing plate 303 and the aluminum strip. Specifically, the temperature sensing device is as follows: Figure 5 As shown. The bimetallic strip with thermal deformation is used as the core temperature sensing material. The different thermal expansion rates of different metals when the temperature changes are used to make the bimetallic strip bend towards the metal with a smaller thermal expansion rate when heated, thus achieving mechanical action.

[0059] like Figure 6 As shown, the main body of the temperature sensing device is composed of a bimetallic strip 401 as a core temperature sensing action element, a lever lock 402, a spring 403 as an indicating action element, a metal jacket 404 and a red alarm 405. Figure 7 As shown, the metal sleeve 404 includes an upper metal sleeve 4041 and a lower metal sleeve 4042. The lower metal sleeve 4042 includes a bimetallic strip 401, a lever lock 402, a spring (the spring is located inside the metal sleeve 404 in the figure, not shown), and a red alarm 405 from bottom to top. Then, the lower metal sleeve 4042 is connected to the upper metal sleeve 4041 by threads. The lower end of the lever supports the bimetallic strip 401, and the upper end clamps the red alarm 405. The spring is also between the red alarm 405 and the bimetallic strip 401, and is in a compressed state when working normally. The upper metal sleeve 4041 has a hole to allow the red alarm 405 to pop out after actuation. There is a pipe clamp at the lower end of the red alarm 405, which can make the spring stuck after popping out. When the temperature at the bottom rises to the preset temperature (thermal defect temperature). The bimetal core temperature sensing element at the bottom of the temperature sensing core is heated. When the bottom temperature reaches the preset temperature, due to the characteristics of the bimetal, the two layers of metal expand to different degrees when heated. The bimetal bends to unlock the lever lock, causing the lever lock to disengage from the slot. The spring releases its elastic force upward to cause the red alarm to pop out, thereby realizing the alarm effect.

[0060] In a specific implementation process, determining the first amount of heat and the second amount of heat at least according to the resistance includes: according to the resistance and the first formula: The first heat Q1 is obtained, where I0 is the power frequency current, R 总 is the resistance, t1 is the first duration; according to the resistance and the second formula: A second heat amount Q2 is obtained, wherein t2 is a second time duration.

[0061] In the above embodiment, according to Joule's law, the corresponding heat can be obtained by only obtaining the experimental time. During the experiment, the duration is relatively easy to obtain, and the obtained duration is also relatively accurate heat, which reduces the operating difficulty of the experimental platform, improves the accuracy of the experimental platform, and at the same time, reduces the cost of the experimental platform.

[0062] Specifically, in order to improve the accuracy of duration acquisition, on the experimental platform, under the same conditions, multiple first durations and multiple second durations are respectively acquired, the target first duration is obtained through the multiple first durations, the target second duration is obtained through the multiple second durations, and the target first duration is updated to the first duration to obtain the first heat, and the target second duration is updated to the second duration to obtain the second heat, wherein the target first duration is the average of the multiple first durations, and the target second duration is the average of the multiple second durations. The first heat is calculated using the target first duration and the second heat is calculated using the target second duration, so as to reduce experimental errors and increase detection accuracy.

[0063] In a specific implementation process, judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount includes: judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount, the second heat amount and the third formula: A relative error σ is obtained; and a magnitude relationship between the relative error σ and a first threshold is determined; when the relative error σ is less than the first threshold, the action of the temperature sensing device meets the accuracy requirement.

[0064] In the above embodiment, the power frequency current is used as the current excitation, and the heat generated when the device reaches the operating temperature and the heat generated when the device is in operation are compared and analyzed to verify the accuracy of the operating temperature design of the core temperature sensing element. By setting the first threshold to determine whether the action of the temperature sensing device meets the accuracy requirements, the experimental difficulty is reduced, and the error setting can also be adjusted according to the needs of the user, which improves the user experience while accurately and reliably determining whether the operating temperature setting of the temperature sensing device meets the needs.

[0065] During the specific implementation process, the method also includes: determining a third heat at least based on the resistance, the third heat being the heat generated by the temperature sensing device under the condition of lightning current passing through the system to be tested; determining a fourth heat at least based on the first duration, the fourth heat being the heat generated by the temperature sensing device under the condition of industrial frequency current passing through the system to be tested; and checking whether the experimental platform meets the rationality requirements based on the third heat and the fourth heat.

[0066] In the above embodiment, mathematical models are established for the heat energy and temperature generated by the ground wire-suspension wire clamp assembly under the action of lightning current and the action of power frequency current, respectively, and the effects of the two on the temperature sensing element are equivalent in combination with the experimental results under the power frequency current. The heat generated by the system to be tested under the action of lightning current is compared with the heat generated by the temperature sensing device under the action of power frequency current. In this way, it is judged whether the construction of the experimental platform is reasonable. When the experimental platform meets the requirements of rationality, the accuracy of the temperature sensing device is judged, which can further increase the accuracy of the experimental platform on the temperature sensing device. Among them, when the experimental platform does not meet the requirements of rationality, further debugging is performed to obtain a reasonable power frequency current.

[0067] In the specific implementation process, the third heat is determined at least based on the resistance, including: determining the fifth heat based on the resistance and Joule's law, wherein the fifth heat is the heat generated by the lightning current flowing through the system to be measured; determining the sixth heat based on the resistance and Gaussian heat source model, wherein the sixth heat is the heat generated by the local breakdown of the system to be measured; determining the third heat based on the fifth heat and the sixth heat, wherein the third heat is the sum of the fifth heat and the sixth heat.

[0068] In the above embodiment, lightning breakdown is a complex process in which various types of heat are generated. In the embodiment, the heat generated by the system to be tested under the lightning current condition is obtained according to the characteristics of the lightning current, that is, the heat mainly generated by the lightning current and the heat generated by the internal breakdown caused by the lightning current. Under the premise of ensuring the accuracy of the experiment, the experimental process is simplified.

[0069] Specifically, the lightning current is injected from the lightning strike point, flows through the ground wire, aluminum tape, suspension wire clamp, fastener, grounding pole tower in sequence, and finally injected into the earth. According to the aircraft lightning protection and experimental standards in the prior art, the standard lightning current waveform has four stages: pilot current, intermediate current, continuous direct current, and re-impact current. The fifth heat can be calculated based on the waveform of the lightning current. At the same time, the ground wire-clamp contact point is locally broken down to generate arc discharge. As a result, part of the heat generated by the lightning current causing local high temperature inside the component is Joule heat, and the other part is arc heat.

[0070] In a specific implementation process, according to the resistance and Joule's law, the fifth heat is determined, including: according to the resistance and the fourth formula: Get the heat Q generated by the pilot current A , where I p is the magnitude of the pilot current, R 总 is the resistance, α is the wave head time of the lightning current, β is the half-peak time of the lightning current, t is the action time of the leading current, t3 is the total action time of the leading current, where the lightning current includes the leading current and the continuous current; according to the resistance and the fifth formula: Get the heat Q generated by continuous current C , where I C is the continuous current, t4 is the total action time of the continuous current; according to the heat Q A and heat Q C , get the fifth heat, where the fifth heat is heat Q A and heat Q C sum.

[0071] Specifically, the Joule heat source generated by the high-frequency pulse component and DC component of the lightning current and the arc heat source of the lightning current are modeled and described: For the high-frequency pulse component A, a double exponential function model is used for mathematical description: iA (t) = I P (e -αt -e β- ) t Where, I p Represents the amplitude of the A component of the lightning current. From the study of the lightning current waveform and its expression, it can be known that the α and β parameters can be calculated according to the existing formula based on the wave head time and half-peak time of the lightning current. For example, if the lightning current wave head and wave tail time constant 1.2 / 50μs (wave head time / half-peak time) specified in the national standard is taken, the values ​​of α and β can be calculated according to the existing method to be 1.473×104 and 2.08×106 respectively. Set the total action time t3 of the A component of the lightning current. Considering that the decay speed of the A component is very fast, t3 can be set to 500μs, at which time the value of the A component is about 10% of its peak value.

[0072] The DC component C can be directly described mathematically using a square wave, and the current magnitude is I C The action time is t4, and the generated arc heat source is mathematically described using the Gaussian heat source model:

[0073]

[0074] In the formula, I C represents the DC component of lightning current, R(t) represents the maximum radius of Gaussian heat source, and r represents the radius of arc heat source.

[0075] The Joule heat and arc heat generated by the lightning current are calculated using the model formula given above: The total resistance of the lightning current through the ground wire-suspension clamp assembly path is taken as R 总 , calculate the heat generated by the lightning current A component using Joule's law: Heat generated by lightning current C component: The total Joule heat generated, that is, the fifth heat, is: Q5 = Q A +Q C .

[0076] In the above embodiment, the fifth heat is the heat generated by the lightning current flowing through the system to be tested, and the standard lightning current waveform has four stages: pilot current, intermediate current, continuous direct current, and re-impact current. According to relevant research on direct damage to OPGW lines caused by lightning strikes, the main contributing components to the damage to metal materials caused by lightning strikes are the pilot current A component that retains a large number of carriers in the metal material and the continuous current C component that injects a large amount of transferred charges into the metal. Therefore, only the influence of components A and C on the heating of the ground wire-clip assembly is considered. By obtaining the heat generated by the pilot current A and the continuous current C, the heat generated by the lightning current flowing through the system to be tested can be obtained, and the heat generated by the lightning current flowing through the system to be tested can be scientifically obtained, and the accurate heat can be further obtained. At the same time, the experimental operation is reduced, and an accurate heat value can be obtained in a simple operation.

[0077] In addition, the arc heat generated is calculated using the Gaussian heat source model formula, that is, the sixth heat Q6. Since the arc action time is almost the same as the lightning current action time, t4 is the arc action time. The arc heat integral calculation formula can be obtained from the model formula given above: Since the lightning current action time is short, the heat loss can be ignored, that is, the total heat generated by the temperature sensing device to reach the operating temperature under the action of the lightning current: Q3 = Q5 + Q6.

[0078] In the specific implementation process, the fourth amount of heat is determined at least according to the first time length, including: obtaining the first temperature, the second temperature and the third temperature of the pressure plate, wherein the pressure plate has a first surface and a second surface, the first surface is in contact with the component to be measured, and the second surface is in contact with the air, the first temperature is the temperature of the first surface, the second temperature is the temperature of the second surface, and the third temperature is the temperature of the air; the seventh amount of heat is determined according to the first time length, the first temperature, the second temperature and the third temperature; the fourth amount of heat is determined according to the first amount of heat and the seventh amount of heat, wherein the fourth amount of heat is the difference between the first amount of heat and the seventh amount of heat.

[0079] In the above embodiment, in the experimental platform, when the current passes through the system to be tested, part of the heat is consumed by the platen, and the heat loss of the platen can be obtained through the temperature inside and outside the platen, and the temperature between the platen and the air, thereby increasing the rationality and accuracy of the experimental platform. Among them, the first temperature is the temperature inside and outside the platen, and the theoretical heat transfer loss can be obtained through the first temperature and the second temperature; the third temperature is the temperature of the air, and the heat convection loss can be obtained through the second temperature and the third temperature. The heat conduction loss and the heat convection loss can be regarded as the heat loss of the platen.

[0080] In a specific implementation process, determining the seventh heat according to the first temperature, the second temperature and the third temperature includes: determining the seventh heat according to the first temperature, the second temperature and the sixth formula: The first heat loss amount q1 is obtained, wherein λ is the thermal conductivity of the material of the pressure plate, A1 is the contact surface area between the pressure plate and the element to be measured, S is the thickness of the pressure plate, and ΔT1 is the difference between the first temperature and the second temperature; according to the second temperature, the third temperature and the seventh formula: q2=aA2ΔT2, the second heat loss amount q2 is obtained, wherein a is the convection heat transfer coefficient, A2 is the contact area between the pressure plate and the air, and ΔT2 is the difference between the second temperature and the third temperature; according to the first time length and the eighth formula: Q4=(q1+q2)t1, the seventh heat amount Q4 is obtained, wherein t1 is the first time length.

[0081] Specifically, the analysis of the heat transfer process inside the suspension clamp-ground wire system shows that when measuring the heat Q set generated when the device reaches the operating temperature, it is necessary to consider the heat transfer loss generated at the contact position between the aluminum tape and the pressure plate, the contact position between the pressure plate and the temperature sensing core, and the convection loss generated at the contact position between the pressure plate and the air. Use the relevant formula to calculate the theoretical heat transfer loss and convection loss. Use the heat conduction loss formula: Among them, q1 is the conduction heat loss per unit time (W), λ is the thermal conductivity of the material (the unit of thermal conductivity is W / (m·K)), A1 is the contact area between the pressure plate and the aluminum tape, ΔT1 is the temperature difference between the upper and lower parts of the pressure plate, and S is the thickness of the pressure plate. Use the heat convection loss formula: q2=aA2ΔT2, where q2 is the convection heat loss per unit time (W), a is the convection heat transfer coefficient (the unit of convection heat transfer coefficient is W / (m2·K)), A2 is the contact area between the pressure plate and the air, and ΔT2 is the temperature difference between the pressure plate and the air. The above two heat loss formulas can be used to obtain the total heat lost when the device reaches the designed operating temperature. According to the actual situation of the experimental platform, the arc heat generated by the system under test under lightning current can be obtained, which further increases the rationality of the experimental platform and simplifies the operation of the experimental platform.

[0082] From these two heat loss formulas, we can get the total heat lost when the device reaches the designed operating temperature: Q4 = (q1 + q2) t1, and get the seventh heat Q4, and the fourth heat is the difference between the first heat and the seventh heat.

[0083] During the specific implementation process, based on the third heat and the fourth heat, it is checked whether the experimental platform meets the rationality requirements, including: judging the size relationship between the first difference and the second threshold, the first difference is the absolute value of the difference between the third heat and the fourth heat; when the first difference is less than the second threshold, the experimental platform meets the rationality requirements.

[0084] Specifically, in the experimental platform, the experimental results under the power frequency current are combined to make the effects of the two on the temperature sensing element equivalent, and the arc heat is increased by the first heat, and the heat generated by the pressure plate is subtracted from the third heat, so that the experimental platform meets the conditions of simulating lightning current, and the interference of other components in the system to be tested on the temperature sensing device is eliminated, thereby increasing the accuracy of the experimental platform. In addition, the difference between the heat generated by the system to be tested under the action of lightning current and the heat energy generated by the ground wire-suspension wire clamp assembly under the action of power frequency current is calculated, and the rationality of the experimental platform is judged by the established second threshold. On the one hand, the setting of the rationality error of the experimental platform can be adjusted according to user needs, and on the other hand, when the experimental platform is reasonable, the accuracy of the temperature sensing device is tested, which improves the accuracy of the test results and the user experience.

[0085] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for detecting thermal damage of overhead lines of the present application will be described in detail below in combination with specific embodiments.

[0086] This embodiment relates to a specific method for detecting thermal damage of overhead lines, comprising the following steps:

[0087] Step S11: Lightning current is injected from the lightning strike point, flows through the ground wire, aluminum tape, suspension wire clamp, fastener, grounding pole tower in sequence, and finally injected into the earth. Referring to the aircraft lightning protection and test standards formulated by SAE (Society of Automotive Engineers), the standard lightning current waveform has four stages: pilot current, intermediate current, continuous DC, and re-impact current. According to relevant research on direct damage to OPGW lines caused by lightning strikes, the main contributing components of metal material damage caused by lightning strikes are the pilot current A component with a large number of carriers remaining in the metal material and the continuous current C component that injects a large amount of transferred charge into the metal. Therefore, only the effects of A and C components on the heating of the ground wire-clamp assembly are considered. At the same time, the ground wire-clamp contact point is locally broken down to generate arc discharge. As a result, part of the heat generated by the lightning current causing local high temperature inside the component is Joule heat, and the other part is arc heat.

[0088] Step S111: Modeling and describing the Joule heat source generated by the high-frequency pulse component and the DC component of the lightning current and the arc heat source of the lightning current:

[0089] The high-frequency pulse component A is mathematically described using a double exponential function model:

[0090] i A (t) = I P (e -αt -e -βt ),

[0091] In the formula, I pRepresents the amplitude of the A component of the lightning current. From the study of lightning current waveforms and their expressions, it can be seen that the α and β parameters can be calculated according to the existing formula based on the wave head time and half-peak time of the lightning current. (This calculation method is an existing method and does not belong to the innovation and protection point of this patent) If the lightning current wave head and wave tail time constant 1.2 / 50μs (wave head time / half-peak time) specified in the national standard is taken, the values ​​of α and β can be calculated according to the existing method to be 1.473×104 and 2.08×106 respectively. Set the total action time t3 of the A component of the lightning current. Taking into account the rapid decay rate of the A component, t3 can be set to 500μs, at which time the value of the A component is about 10% of its peak value.

[0092] The DC component C can be directly described mathematically using a square wave, and the current magnitude is I C The action time is t4.

[0093] The Gaussian heat source model is used to mathematically describe the arc heat source:

[0094]

[0095] In the formula, I C represents the DC component of lightning current, R(t) represents the maximum radius of Gaussian heat source, and r represents the radius of arc heat source.

[0096] Step S112: Calculate the Joule heat and arc heat generated by the lightning current using the model formula given above.

[0097] The total resistance of the lightning current passing through the ground wire-suspension clamp assembly path is taken as R 总 , calculate the heat generated by the lightning current A component using Joule's law:

[0098]

[0099] And the heat generated by the lightning current C component:

[0100]

[0101] The total Joule heat generated is:

[0102] Q5=Q A +Q C ,

[0103] The arc heat Q6 generated is calculated using the Gaussian heat source model formula. The arc action time is almost the same as the lightning current action time. The arc heat integral calculation formula can be obtained from the model formula given above:

[0104]

[0105] Since the lightning current action time is short, the heat loss can be ignored, that is, the total heat generated by the temperature sensing device to reach the operating temperature T under the action of the lightning current:

[0106] Q3=Q5+Q6.

[0107] Step S12: Establish an experimental platform with power frequency current I0 as excitation and suspension clamp-ground wire system as excitation object. The ground wire, the contact resistance of the ground wire and the aluminum tape, and the aluminum tape are all incorporated into the current loop.

[0108] In the experiment on this experimental platform, the time t1 required for the device to reach the designed operating temperature under the excitation of the power frequency current and the time t2 required for the temperature sensing device to operate were measured.

[0109] Considering the ground wire-suspension clamp assembly as a whole, the heat generated in this part to make the device reach the designed operating temperature under power frequency current is:

[0110]

[0111] The heat generated in this part to make the temperature sensing device operate under power frequency current:

[0112]

[0113] Step S13: Analysis of the heat transfer process inside the suspension clamp-ground wire system shows that when measuring the heat generated when the device reaches the operating temperature, it is necessary to consider the heat transfer loss generated at the contact position between the aluminum tape and the pressure plate, the contact position between the pressure plate and the temperature sensing core, and the convection loss generated at the contact position between the pressure plate and the air. Use the relevant formula to calculate the theoretical heat transfer loss and convection loss. Use the heat conduction loss formula:

[0114]

[0115] Among them, q1 is the conduction heat loss per unit time (W), λ is the thermal conductivity of the material (the unit of thermal conductivity is W / (m·K)), A1 is the contact area between the pressing plate and the aluminum tape, ΔT1 is the temperature difference between the upper and lower parts of the pressing plate, and S is the thickness of the pressing plate.

[0116] Using the heat convection loss formula:

[0117] q2=aA2ΔT2,

[0118] Among them, q2 is the convective heat loss per unit time (W), a is the convective heat transfer coefficient (the unit of convective heat transfer coefficient is W / (m2·K)), A2 is the contact area between the pressure plate and the air, and ΔT2 is the temperature difference between the pressure plate and the air.

[0119] The above two heat loss formulas can be used to obtain the total heat loss when the device reaches the designed operating temperature:

[0120] Q4=(q1+q2)t1,

[0121] The seventh heat Q4 is obtained, which is the total heat lost when the device reaches the designed operating temperature.

[0122] The heat required to make the device reach the designed operating temperature is:

[0123] Q5=Q1+Q4,

[0124] Among them, Q5 is the fourth heat.

[0125] Compare and analyze whether the sizes of Q3 and Q5 are approximately equal within a certain error to verify the rationality of the design of the experimental platform.

[0126] Step S14: Compare and analyze the two heat quantities Q1 and Q2 calculated by S2, and calculate the relative error:

[0127]

[0128] Furthermore, it is verified whether the operating temperature setting of the temperature sensing device is accurate and reliable within a certain error under this experimental method.

[0129] Among them, the above method steps are various methods for obtaining some parameters.

[0130] Analysis of the heat transfer process inside the suspension clamp-ground wire system shows that when measuring the heat Q set generated when the device reaches the operating temperature, it is necessary to consider the heat transfer loss generated at the contact position between the aluminum tape and the pressure plate, the contact position between the pressure plate and the temperature sensing core, and the convection loss generated at the contact position between the pressure plate and the air. Use the relevant formula to calculate the theoretical heat transfer loss and convection loss. Use the heat conduction loss formula:

[0131]

[0132] In the formula, a is the median current and b is the steepness coefficient, which can be determined according to the lightning activity in the region. When the a and b parameters of a certain region cannot be obtained, the IEEE recommended values ​​of a=31 and b=2.6 can also be used. According to the standard recommended values, 95% of the lightning stroke amplitudes are greater than 10kA, and 50% of the lightning stroke amplitudes are greater than 31kA. The commonly used different probabilities and corresponding lightning current amplitudes are shown in Table 1.

[0133] Table 1

[0134] Lightning current amplitude probability P <![CDATA[The corresponding lightning current amplitude I P (kA)]]> 0.99 5.29 0.95 10 0.5 31 0.1 72.2 0.05 96.2 0.01 181.5 0.005 237.4

[0135] The DC component C can refer to the aircraft lightning protection standard issued by SAE (American Society of Automotive Engineers) to select parameters of different levels. Now take the current peak value I CThe lightning current C component (continuous current) parameters are shown in Table 2.

[0136] Table 2

[0137]

[0138] In relevant research, the radius r of the arc heat source is usually taken in the range of 2.5 to 15 mm. For the arc discharge caused by lightning strike near the line clamp assembly of the overhead line, it is considered to be a discharge inside a tiny gap, and the radius of the arc heat source is taken as 5 mm.

[0139] Resistor R 总 The black box experiment can be used to obtain the value, that is, the components corresponding to the resistor are regarded as a whole, and the corresponding value can be calculated after the response is measured by adding external excitation. The black box experiment can be completed by existing impedance measuring instruments, bridge method resistance measurement and other means.

[0140] The area A1 of the contact surface between the pressure plate and the aluminum strip can be obtained by the elliptical cylindrical conductive bridge model, and its calculation formula is:

[0141]

[0142] Where n is the number of bolts to which torque is applied (here n=4); T C is the bolt torque (10 N·m or more when the bolt is tightened, and 1 N·m or less when the bolt is loosened); K is the thread friction coefficient, usually 0.2; d b is the nominal diameter of the bolt; ζ is the coefficient characterizing the contact condition, and its value range is between 0.3 and 0.6. It is usually taken as 0.45 in engineering calculations; H is the Brinell hardness of the contact interface material, which is obtained by measuring with a digital Brinell hardness tester.

[0143] The contact area A2 between the pressure plate and the air does not need to take into account the bottom surface of the pressure plate in close contact with the ground wire wrapped with the aluminum tape, that is, the actual contact area is the upper surface and side surface of the pressure plate, and the specific value can be calculated by measuring the actual size of the pressure plate.

[0144] The steps of the experimental process of the experimental platform may include:

[0145] Step S21, check the paperless recorder and thermocouple settings;

[0146] Step S22, check electrical connection;

[0147] Step S23, turning on the main power supply, adjusting the control loop of the high current generator, and using a clamp meter to obtain the current value at the output end of the step-down transformer;

[0148] Step S24, when the current reaches the required value, quickly cut off the main power switch, keep the position of the voltage regulator paddle unchanged, and obtain the current value I0;

[0149] Step S5, observing the temperature of the overhead ground wire-suspension wire clamp assembly by a thermocouple temperature measuring device until the overall temperature drops to room temperature ±5%;

[0150] Step S6, turning on the main power switch so that the set current value is instantaneously applied to the sample for timing;

[0151] Step S7, obtaining the thermocouple value until the device reaches the designed operating temperature and the timing ends, cutting off the power supply of the generating circuit and obtaining the duration;

[0152] Step S8, repeating steps S4, S5 and S6, obtaining the duration multiple times and determining the average value, which is recorded as t1;

[0153] Step S9, repeating steps S4 and S5, constantly acquiring the thermocouple value until the device generates an action timing, cutting off the power supply of the generating circuit, and acquiring the duration;

[0154] Step S10, repeat step 8, obtain the duration multiple times and determine the average value, which is recorded as t2.

[0155] Alternatives to the above methods include lightning strike experiments, finite element simulation experiments, constant temperature box experiments, and other methods. One method is to use lightning current to directly excite the sample on the experimental platform, but the existing excitation device cannot fully simulate the lightning current, and the lightning current energy is huge, which poses a great safety hazard. Another method is to use the finite element simulation experimental method, but this method cannot fully simulate the actual situation, and requires quantitative processing of the parameters of the experimental platform, the data is complicated, and the amount of calculation is large. The platform is difficult to build, and the adjustability of the structural parameters, boundary conditions, and excitation settings is poor, which requires a lot of time and effort. Another method is to use the constant temperature box experimental method. The disadvantage is that the physical process in the constant temperature box is far different from the physical process during the actual lightning strike, and it will produce a large error compared with the short-term high temperature of the lightning strike. This experimental method uses a large current generator as a constant current excitation source, and builds an experimental platform under actual application scenarios, which has great advantages compared with alternatives.

[0156] According to another aspect of the present application, a device for detecting thermal damage of an overhead line is provided, such as Figure 8 As shown, including:

[0157] A first acquisition unit 10 is used to acquire the resistance of the system to be tested, wherein the experimental platform includes a connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, and the pressure plate is connected to the temperature sensing device and the component to be tested;

[0158] A control unit 20, used to control the excitation module to apply a power frequency current to the system to be measured, so as to obtain a first time duration for the temperature of the system to be measured to reach a preset temperature and a second time duration for the temperature sensing device to be actuated;

[0159] A determination unit 30, configured to determine a first amount of heat and a second amount of heat at least based on the resistance, wherein the first amount of heat is heat generated when the temperature of the system to be measured reaches a preset temperature, and the second amount of heat is heat generated by the system to be measured when the temperature sensing device is actuated;

[0160] A judging unit 40, used to judge whether the action of the temperature sensing device is correct according to the first heat amount and the second heat amount;

[0161] The detection unit 50 is used to detect the thermal damage of the overhead line using the temperature sensing device when the action of the temperature sensing device meets the accuracy requirement.

[0162] Through this embodiment, the accuracy and reliability of the temperature sensing device are tested through the constructed experimental platform to overcome the shortcomings of the thermal damage experimental method for overhead lines in the power grid system in the prior art, wherein the experimental platform includes a connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a test element and a pressure plate, the pressure plate connects the temperature sensing device and the test element, the first acquisition unit is used to obtain the resistance of the system to be tested, and the resistance of the system to be tested is obtained to increase the accuracy of the detection; the control unit is used to control the excitation module to apply an industrial frequency current to the system to be tested, so as to obtain the first time for the temperature of the system to be tested to reach a preset temperature and the second time for the temperature sensing device to act, by using the industrial frequency current as the excitation current, the physical action process of the lightning current can be equivalent, the current path is the same as the lightning current path, and the heat generated at the temperature sensing part during the action of the lightning current can be equivalent, so as to avoid the artificial lightning induction method. High cost and harsh conditions reduce the danger of artificial drainage; the determination unit is used to determine the first heat and the second heat according to at least the resistance, wherein the first heat is the heat generated when the temperature of the system to be measured reaches the preset temperature, and the second heat is the heat generated by the system to be measured when the temperature sensing device is activated; the judgment unit is used to judge whether the action of the temperature sensing device meets the accuracy requirements based on the first heat and the second heat, and compare and analyze the heat generated when the device reaches the action temperature and the heat generated when the device is activated with the power frequency current as the current excitation, to verify the accuracy of the action temperature design of the core temperature sensing element; the detection unit is used to use the temperature sensing device to detect the thermal damage of the overhead line when the action of the temperature sensing device meets the accuracy requirements, and use the temperature sensing device that meets the accuracy to detect the thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection. The heat equivalent experimental method using the power frequency current as the excitation in the above method can be equivalent to the physical action process of the lightning current, and its current path is the same as the lightning current path, and can be equivalent to the heat generated by the temperature sensing part during the action of the lightning current. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor.

[0163] In a specific implementation process, the determination unit includes a first calculation unit and a second calculation unit, wherein the first calculation unit is used to calculate the value according to the resistance and the first formula: The first heat Q1 is obtained, where I0 is the power frequency current, R 总 is the resistance, t1 is the first time length; the second calculation unit is used for calculating the resistance according to the second formula: The second heat Q2 is obtained, where t2 is the second duration. According to Joule's law, the corresponding heat can be obtained by only obtaining the experimental time. During the experiment, the duration is relatively easy to obtain, and the obtained duration is also relatively accurate heat, which reduces the operating difficulty of the experimental platform, improves the accuracy of the experimental platform, and at the same time, reduces the cost of the experimental platform.

[0164] In a specific implementation process, the judgment unit includes a third calculation unit, a first judgment subunit and a first determination subunit, wherein the third calculation unit is used to determine the heat according to the first heat, the second heat and the third formula: The relative error σ is obtained; the first judgment subunit is used to judge the size relationship between the relative error σ and the first threshold; the first determination subunit is used to determine that the action of the temperature sensing device meets the accuracy requirement when the relative error σ is less than the first threshold. Using industrial frequency current as current excitation, the heat generated when the device reaches the action temperature and the heat generated when the device is actuated are compared and analyzed to verify the accuracy of the action temperature design of the core temperature sensing element. By setting the first threshold to determine whether the action of the temperature sensing device meets the accuracy requirement, the difficulty of the experiment is reduced, and the error setting can also be adjusted according to user needs, which improves the user experience while accurately and reliably determining whether the action temperature setting of the temperature sensing device meets the needs.

[0165] In the specific implementation process, the detection device package also includes: a first determination unit, a second determination unit and a first detection subunit, wherein the first determination unit is used to determine the third heat according to at least the resistance, and the third heat is the heat generated by the temperature sensing device under the condition of lightning current passing through the system to be tested; the second determination unit is used to determine the fourth heat according to at least the first duration, and the fourth heat is the heat generated by the temperature sensing device under the condition of power frequency current passing through the system to be tested; the first detection subunit verifies whether the experimental platform meets the rationality requirements based on the third heat and the fourth heat. The accuracy judgment of the temperature sensing device by the experimental platform can be further increased; wherein, if the experimental platform does not meet the rationality requirements, further debugging is performed to obtain a reasonable power frequency current.

[0166] In the specific implementation process, the first determination unit includes a second determination subunit, a third determination subunit and a fourth determination subunit, wherein the second determination subunit is used to determine the fifth heat according to resistance and Joule's law, wherein the fifth heat is the heat generated by the lightning current flowing through the system to be tested; the third determination subunit is used to determine the sixth heat according to resistance and Gaussian heat source model, wherein the sixth heat is the heat generated by the partial breakdown of the system to be tested; the fourth determination subunit is used to determine the third heat according to the fifth heat and the sixth heat, wherein the third heat is the sum of the fifth heat and the sixth heat. This simplifies the experimental process while ensuring the accuracy of the experiment.

[0167] In a specific implementation process, the second determining subunit includes a third calculating unit, a fourth calculating unit and a fifth determining subunit, wherein the third determining subunit is used to determine the value of the resistor according to the fourth formula: Get the heat Q generated by the pilot current A , where I p is the magnitude of the pilot current, R 总is the resistance, α is the wave head time of the lightning current, β is the half-peak time of the lightning current, t is the action time of the leading current, t3 is the total action time of the leading current, wherein the lightning current includes the leading current and the continuous current; the fourth calculation unit is used to calculate the value according to the resistance and the fifth formula: Get the heat Q generated by continuous current C , where I C is the continuous current, t4 is the total action time of the continuous current; the fifth determination subunit is used to determine the heat Q A and heat Q C , get the fifth heat, where the fifth heat is heat Q A and heat Q C By obtaining the heat generated by the pilot current A and the continuous current C, the heat generated by the lightning current flowing through the system to be tested can be obtained. The heat generated by the lightning current flowing through the system to be tested can be scientifically obtained, and the accurate heat can be further obtained. At the same time, the experimental operation is reduced, and accurate heat values ​​can be obtained in simple operations.

[0168] In the specific implementation process, the second determination unit includes a first acquisition subunit, a sixth determination subunit and a seventh determination subunit, wherein the first acquisition subunit is used to acquire the first temperature, the second temperature and the third temperature of the pressure plate, wherein the pressure plate has a first surface and a second surface, the first surface is in contact with the element to be measured, the second surface is in contact with the air, the first temperature is the temperature of the first surface, the second temperature is the temperature of the second surface, and the third temperature is the temperature of the air; the sixth determination subunit is used to determine the seventh heat according to the first duration, the first temperature, the second temperature and the third temperature; the seventh determination subunit is used to determine the fourth heat according to the first heat and the seventh heat, wherein the fourth heat is the difference between the first heat and the seventh heat. This increases the rationality and accuracy of the experimental platform.

[0169] In a specific implementation process, the sixth determining subunit includes a fifth calculating unit, a sixth calculating unit and a seventh calculating unit, wherein the fifth calculating unit is used to calculate the temperature according to the first temperature, the second temperature and the sixth formula: The first heat loss q1 is obtained, where λ is the thermal conductivity of the material of the pressure plate, A1 is the area of ​​the contact surface between the pressure plate and the element to be tested, S is the thickness of the pressure plate, and ΔT1 is the difference between the first temperature and the second temperature; the sixth calculation unit is used to obtain the second heat loss q2 according to the second temperature, the third temperature and the seventh formula: q2 = aA2ΔT2, where a is the convection heat transfer coefficient, A2 is the contact area between the pressure plate and the air, and ΔT2 is the difference between the second temperature and the third temperature; the seventh calculation unit is used to obtain the seventh heat Q4 according to the first time length and the eighth formula: Q4 = (q1 + q2) t1, where t1 is the first time length. According to the actual situation of the experimental platform, the arc heat generated by the system to be tested under the lightning current can be obtained, which further increases the rationality of the experimental platform and simplifies the operation of the experimental platform.

[0170] In the specific implementation process, the first detection subunit includes a second judgment subunit and an eighth determination subunit, wherein the second judgment subunit includes judging the magnitude relationship between the first difference and the second threshold, the first difference being the absolute value of the difference between the third heat and the fourth heat; the eighth determination subunit is used to determine that the experimental platform meets the rationality requirement when the first difference is less than the second threshold. On the one hand, the setting of the rationality error of the experimental platform can be adjusted according to the needs of the user, and on the other hand, when the experimental platform is reasonable, the accuracy of the temperature sensing device is detected, which improves the accuracy of the detection results and the user experience.

[0171] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0172] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0173] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0174] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0175] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0176] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0177] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0178] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0179] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0180] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0181] 1) The detection method of thermal damage of overhead lines of the present application overcomes the shortcomings of the experimental method for thermal damage of overhead lines in the power grid system in the prior art by testing the accuracy and reliability of the action of the temperature sensing device through the constructed experimental platform, wherein the experimental platform includes a connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connects the temperature sensing device and the component to be tested, and obtains the resistance of the system to be tested to increase the accuracy of the detection; the excitation module is controlled to apply an industrial frequency current to the system to be tested to obtain the first time duration for the temperature of the system to be tested to reach a preset temperature and the second time duration for the temperature sensing device to act, and the industrial frequency current is used as the excitation current to be equivalent to the physical action process of the lightning current, and its current path is the same as the lightning current path, and can be equivalent to the heat generated at the temperature sensing part during the action of the lightning current, thereby avoiding the artificial lightning induction method. The method leads to high costs and harsh conditions, and reduces the dangers brought by artificial drainage; at least according to the resistance, determine the first heat and the second heat, wherein the first heat is the heat generated when the temperature of the system to be tested reaches the preset temperature, and the second heat is the heat generated by the system to be tested when the temperature sensing device is activated. According to the first heat and the second heat, judge whether the action of the temperature sensing device meets the accuracy requirements, use the power frequency current as the current excitation, compare and analyze the heat generated when the device reaches the action temperature and the heat generated when the device is activated, and verify the accuracy of the action temperature design of the core temperature sensing element; when the action of the temperature sensing device meets the accuracy requirements, use the temperature sensing device to detect the thermal damage of the overhead line, and use the temperature sensing device that meets the accuracy to detect the thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection. The heat equivalent experimental method using the power frequency current as the excitation can be equivalent to the physical action process of the lightning current. Its current path is the same as the lightning current path, and it can be equivalent to the heat generated by the temperature sensing part during the action of the lightning current. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor.

[0182] 2) The detection device for thermal damage of overhead lines of the present application, through this embodiment, the accuracy and reliability of the action of the temperature sensing device are tested by the constructed experimental platform to overcome the shortcomings of the experimental method for thermal damage of overhead lines in the power grid system in the prior art, wherein the experimental platform includes a connected system to be tested and an excitation module, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, the pressure plate connects the temperature sensing device and the component to be tested, the first acquisition unit is used to obtain the resistance of the system to be tested, and the resistance of the system to be tested is obtained to increase the accuracy of the detection; the control unit is used to control the excitation module to apply an industrial frequency current to the system to be tested to obtain the first time for the temperature of the system to be tested to reach a preset temperature and the second time for the temperature sensing device to act, by using the industrial frequency current as the excitation current, the physical action process of the lightning current can be equivalent, the current path is the same as the lightning current path, and the heat generated at the temperature sensing part during the action of the lightning current can be equivalent, Avoid the high cost and harsh conditions caused by artificial lightning induction methods, and reduce the danger brought by artificial lightning induction; the determination unit is used to determine the first heat and the second heat according to at least the resistance, wherein the first heat is the heat generated when the temperature of the system to be measured reaches the preset temperature, and the second heat is the heat generated by the system to be measured when the temperature sensing device is activated; the judgment unit is used to judge whether the action of the temperature sensing device meets the accuracy requirements based on the first heat and the second heat, and compare and analyze the heat generated when the device reaches the action temperature and the heat generated when the device is activated with the power frequency current as the current excitation, and verify the accuracy of the action temperature design of the core temperature sensing element; the detection unit is used to use the temperature sensing device to detect the thermal damage of the overhead line when the action of the temperature sensing device meets the accuracy requirements, and use the temperature sensing device that meets the accuracy to detect the thermal damage and thermal defects of the overhead line, which simplifies the detection method and increases the accuracy of the detection. The heat equivalent experimental method using the power frequency current as the excitation in the above method can be equivalent to the physical action process of the lightning current, and its current path is the same as the lightning current path, and can be equivalent to the heat generated by the temperature sensing part during the action of the lightning current. At the same time, this experimental method also has the advantages of low cost, convenient operation, and high safety factor.

[0183] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting thermal damage of overhead lines, characterized in that: include: Obtaining the resistance of the system to be tested, wherein the experimental platform includes the system to be tested and an excitation module connected, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, and the pressure plate connects the temperature sensing device and the component to be tested; Controlling the excitation module to apply a power frequency current to the system to be measured, so as to obtain a first time duration for the temperature of the system to be measured to reach a preset temperature and a second time duration for the temperature sensing device to be actuated; Determine a first heat amount and a second heat amount at least according to the resistance, wherein the first heat amount is the heat generated when the temperature of the system to be measured reaches the preset temperature, and the second heat amount is the heat generated when the temperature sensing device is actuated. judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount; In the case where the action of the temperature sensing device meets the accuracy requirement, the temperature sensing device is used to detect thermal damage to the overhead line.

2. The detection method according to claim 1, characterized in that: Determining a first amount of heat and a second amount of heat based at least on the resistance includes: According to the resistor and the first formula: The first heat Q1 is obtained, where I0 is the power frequency current, R 总 is the resistance, t1 is the first duration; According to the resistance and the second formula: The second heat Q2 is obtained, wherein t2 is the second time duration.

3. The detection method according to claim 1, characterized in that: Judging whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount includes: According to the first heat, the second heat and the third formula: Get the relative error σ; Determine the magnitude relationship between the relative error σ and a first threshold; When the relative error σ is smaller than the first threshold, the operation of the temperature sensing device meets the accuracy requirement.

4. The detection method according to claim 1, characterized in that: The method further comprises: Determine a third amount of heat at least according to the resistance, where the third amount of heat is the heat generated by the system to be measured when the temperature sensing device passes a lightning current; Determine a fourth amount of heat at least according to the first time period, where the fourth amount of heat is the heat generated by the system to be measured when the temperature sensing device passes the power frequency current; According to the third heat and the fourth heat, whether the experimental platform meets the rationality requirement is checked.

5. The detection method according to claim 4, characterized in that: Determining the third amount of heat at least according to the resistance includes: Determine a fifth amount of heat according to the resistance and Joule's law, wherein the fifth amount of heat is heat generated by the lightning current flowing through the system to be tested; Determine a sixth amount of heat according to the resistance and the Gaussian heat source model, wherein the sixth amount of heat is heat generated by a local breakdown of the system to be tested; The third heat amount is determined according to the fifth heat amount and the sixth heat amount, wherein the third heat amount is the sum of the fifth heat amount and the sixth heat amount.

6. The detection method according to claim 5, characterized in that: According to the resistance and Joule's law, determining the fifth amount of heat comprises: According to the resistance and the fourth formula: Get the heat Q generated by the pilot current A , where I p is the magnitude of the pilot current, R 总 is the resistance, α is the wave front time of the lightning current, β is the half-peak time of the lightning current, t is the action time of the pilot current, t3 is the total action time of the pilot current, wherein the lightning current includes the pilot current and the continuous current; According to the resistance and the fifth formula: The heat Q generated by the continuous current is obtained C , where I C is the continuous current, and t4 is the total action time of the continuous current; According to the heat Q A and the heat Q C , obtain the fifth heat, wherein the fifth heat is the heat Q A and the heat Q C sum.

7. The detection method according to claim 4, characterized in that: Determining the fourth amount of heat at least according to the first duration includes: Acquire a first temperature, a second temperature, and a third temperature of the pressing plate, wherein the pressing plate has a first surface and a second surface, the first surface is in contact with the device under test, the second surface is in contact with air, the first temperature is the temperature of the first surface, the second temperature is the temperature of the second surface, and the third temperature is the temperature of the air; determining a seventh amount of heat according to the first duration, the first temperature, the second temperature, and the third temperature; The fourth heat amount is determined according to the first heat amount and the seventh heat amount, wherein the fourth heat amount is a difference between the first heat amount and the seventh heat amount.

8. The detection method according to claim 7, characterized in that: Determining a seventh amount of heat according to the first temperature, the second temperature, and the third temperature includes: According to the first temperature, the second temperature and the sixth formula: A first heat loss q1 is obtained, wherein λ is the thermal conductivity of the material of the pressing plate, A1 is the area of ​​the contact surface between the pressing plate and the element to be measured, S is the thickness of the pressing plate, and ΔT1 is the difference between the first temperature and the second temperature; According to the second temperature, the third temperature and the seventh formula: q2=aA2ΔT2, a second heat loss q2 is obtained, wherein a is the convection heat transfer coefficient, A2 is the contact area between the pressure plate and the air, and ΔT2 is the difference between the second temperature and the third temperature; The seventh heat Q4 is obtained according to the first time length and the eighth formula: Q4=(q1+q2)t1, wherein t1 is the first time length.

9. The detection method according to claim 4, characterized in that: According to the third heat amount and the fourth heat amount, checking whether the experimental platform meets the rationality requirement includes: Determine a magnitude relationship between a first difference and a second threshold, wherein the first difference is an absolute value of a difference between the third amount of heat and the fourth amount of heat; When the first difference is smaller than the second threshold, the experimental platform meets the rationality requirement.

10. A device for detecting thermal damage of overhead lines, characterized in that: include: A first acquisition unit is used to acquire the resistance of the system to be tested, wherein the experimental platform includes the system to be tested and an excitation module connected, the system to be tested includes a temperature sensing device, a component to be tested and a pressure plate, and the pressure plate connects the temperature sensing device and the component to be tested; A control unit, used for controlling the excitation module to apply a power frequency current to the system to be measured, so as to obtain a first time duration for the temperature of the system to be measured to reach a preset temperature and a second time duration for the temperature sensing device to be actuated; a determination unit, configured to determine a first amount of heat and a second amount of heat at least according to the resistance, wherein the first amount of heat is heat generated when the temperature of the system to be measured reaches the preset temperature, and the second amount of heat is heat generated when the temperature sensing device is actuated; a judging unit, configured to judge whether the action of the temperature sensing device meets the accuracy requirement according to the first heat amount and the second heat amount; The detection unit is used to detect the thermal damage of the overhead line by using the temperature sensing device when the action of the temperature sensing device meets the accuracy requirement.

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