CN107703001B - Method for testing operation parameters of power transmission and transformation equipment during copper conductor fracture - Google Patents
Method for testing operation parameters of power transmission and transformation equipment during copper conductor fracture Download PDFInfo
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 230000005540 biological transmission Effects 0.000 title claims abstract description 31
- 238000012360 testing method Methods 0.000 title claims abstract description 23
- 230000009466 transformation Effects 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 19
- 239000004020 conductor Substances 0.000 title claims description 29
- 229910052802 copper Inorganic materials 0.000 title claims description 29
- 239000010949 copper Substances 0.000 title claims description 29
- 238000004088 simulation Methods 0.000 claims abstract description 42
- 238000004458 analytical method Methods 0.000 claims abstract description 29
- 238000009864 tensile test Methods 0.000 claims abstract description 14
- 238000005070 sampling Methods 0.000 claims abstract description 4
- 238000002474 experimental method Methods 0.000 claims description 21
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 9
- 238000007431 microscopic evaluation Methods 0.000 claims description 7
- 238000003917 TEM image Methods 0.000 claims description 5
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 3
- 238000004627 transmission electron microscopy Methods 0.000 claims description 3
- 238000004080 punching Methods 0.000 claims description 2
- 238000004626 scanning electron microscopy Methods 0.000 abstract 1
- 238000005498 polishing Methods 0.000 description 9
- 230000001066 destructive effect Effects 0.000 description 4
- 238000001000 micrograph Methods 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 238000013021 overheating Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005520 electrodynamics Effects 0.000 description 1
- DZGCGKFAPXFTNM-UHFFFAOYSA-N ethanol;hydron;chloride Chemical compound Cl.CCO DZGCGKFAPXFTNM-UHFFFAOYSA-N 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 238000012800 visualization Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/18—Performing tests at high or low temperatures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/32—Polishing; Etching
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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Abstract
The invention relates to a method for testing operation parameters of a copper wire of electric transmission and transformation equipment during fracture, which comprises the steps of sampling from the actually blown equipment, selecting intact wires of the same specification, preparing high-temperature simulation samples, performing Gleeble tensile tests at different temperatures, performing metallographic analysis on fractures of the actually fractured wires and the GLEEBLE fractured wires, performing SEM analysis on the fractures of the actually fractured wires and the GLEEBLE fractured wires, performing TEM analysis on the fractures of the actually fractured wires and the GLEEBLE fractured wires, and the like.
Description
Technical Field
The invention relates to a method for testing operation parameters of power transmission and transformation equipment when a copper conductor is broken, and belongs to the technical field of metal materials.
Background
Copper wires are widely applied to power transmission and transformation equipment, and wire breakage is one of common faults when the power transmission and transformation equipment operates. When the fracture occurs, the fracture often bears larger electrodynamic force and large current, and the fracture occurs at high temperature, so that the normal operation of the power transmission and transformation equipment is influenced. The operation parameters of the copper conductor when the copper conductor is broken, including current, temperature when the copper conductor is broken and magnitude of borne external force, are determined, and the method has important significance for analyzing the cause of the broken copper conductor and avoiding similar accidents.
At the moment of the operation fracture of the electric transmission and transformation equipment wire, the current often exceeds the designed current by several times, the wire is caused to generate heat and the temperature rises, meanwhile, the electric transmission and transformation equipment bears the action of larger electric power at the moment of the large-amplitude change of the parameter, the wire is easy to fracture under the combined action of high temperature and electric power, the fracture is generally completed in a short time, and the operation parameter at the moment of the fracture cannot be recorded according to the current monitoring means. If the destructive test is directly carried out on the similar equipment and then the microscopic analysis is carried out, the destructive test under series parameters is often required to be carried out on a plurality of equipment, the cost is too high, and the effect cannot necessarily meet the expected requirement.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a method for testing operation parameters of power transmission and transformation equipment when a copper conductor is broken, which does not need to perform destructive tests under series of parameters on a plurality of similar equipment and has low cost.
The breakage of the wire of the power transmission and transformation equipment is mainly a factor of two aspects: the invention provides a method for analyzing and utilizing high temperature simulation and loading by combining the characteristics of power transmission and transformation equipment, and provides a method for simulating an overheating and short-circuit high-temperature environment and applying a load by utilizing a Gleeble high-temperature tensile testing machine, breaking a copper wire, analyzing a fracture appearance by using a metallographic phase analysis overheating structure and a scanning electron microscope, analyzing dislocation change of the copper wire by using a transmission electron microscope, and comparing the dislocation change with the indexes of the actually broken wire, so that the operating parameters of the copper wire at the moment of breaking are obtained.
The specific technical scheme is as follows:
a method for testing operation parameters of power transmission and transformation equipment when a copper conductor is broken comprises the following steps:
(1) actual broken wire sampling: finding two copper conductors which are cut into two parts from power transmission and transformation equipment with faults, taking samples with the length of 10mm from the fracture point along the length direction of the copper conductors respectively, and taking samples while paying attention to the fact that the fracture is not damaged, wherein one sample is marked as A and is used for metallographic analysis; the other sample, labeled B, was used for microscopic analysis;
(2) preparation of high-temperature simulation sample: selecting a lead wire which is the same as the broken copper lead wire, processing the lead wire into a tensile sample, and performing a Gleeble tensile test;
(3) gleeble tensile experiments at different temperatures: adopting a Gleeble3800 thermal simulation experiment machine, setting the experiment temperature to be 100 ℃, 150 ℃, 200 ℃ and 250 ℃ respectively, performing a group of stretching experiments of 3-5 high-temperature simulation samples at each temperature to obtain a relation curve of displacement and stretching force at each experiment temperature, wherein the broken high-temperature simulation samples are divided into two parts, one part is marked as A 'for metallographic analysis, and the other part is marked as B' for microscopic analysis;
(4) metallographic structure analysis: selecting a part A' of a high-temperature simulation sample subjected to tensile fracture in a Gleeble tensile test, performing a metallographic analysis test, recording a metallographic structure, and performing metallographic analysis on the part A of the actually fractured lead to compare the appearance of the overheated structure; determining a simulated sample with the same metallographic structure as the actual fracture lead;
(5) scanning electron microscope analysis: carrying out scanning electron microscope analysis on fracture morphology of a simulation sample of a Gleeble tensile test at different temperatures and fracture morphology of an actually fractured lead, and finding out a simulation sample which is similar to the fracture morphology of the actually fractured lead;
(6) transmission electron microscopy analysis: preparing a high-temperature simulation sample B' part after being pulled off in a Gleeble tensile experiment and a part B of an actual broken lead into TEM samples, observing under a transmission electron microscope, analyzing the dislocation density at a fracture, and judging the simulation sample which is closest to the actual broken lead fracture according to a TEM image;
(7) determination of the operating parameters at break: finding out a simulation sample which is closest to the fracture metallographic structure, the fracture morphology and the dislocation density of the actual fractured conductor, and determining the magnitude and the temperature of the electric force borne by the actual conductor when the fracture occurs according to the test parameters of the simulation sample.
Further, in the step (3), when the Gleeble tensile experiment is carried out, each group of simulation samples is controlled within 300 seconds according to a temperature rise-heat preservation program.
Further, in the step (3), a Gleeble stretching experiment was performed at a stretching rate of 2.5 mm/min.
Further, in the step (6), the preparation of the TEM sample comprises the steps of cutting, mechanical thinning, punching, mechanical thinning, pit and ion thinning.
Further, in the step (7), in the process of finding out the simulation sample which is the closest to the actual fracture wire fracture metallographic structure, the fracture morphology and the dislocation density, two simulation samples which are the closest to the actual fracture wire fracture metallographic structure, the fracture morphology and the dislocation density are determined, the temperature ranges corresponding to the two simulation sample tensile experiments are further divided into small intervals, and the experiment operations of the steps (3), (4), (5) and (6) are repeated, so that the simulation sample which is the closest to the actual fracture wire fracture metallographic structure, the fracture morphology and the dislocation density is determined.
Has the advantages that: according to the invention, a tensile test is carried out on the copper wire by high-temperature tension, and then the fracture parameter closest to the actual fracture is determined by comprehensively judging the fracture property, the dislocation density and the metallographic structure, so that the actual fracture parameter of the power transmission and transformation equipment wire is obtained. The judgment method does not need to spend high cost to carry out destructive tests under series parameters on actual power transmission and transformation equipment, and can obtain the operation parameters which are closest to the instant of the occurrence of the operation fracture, thereby providing effective criteria for accident analysis.
Drawings
FIG. 1 is a metallographic structure morphology of an actual fractured wire;
FIG. 2 is a scanning electron micrograph (500 times magnification) of the fracture morphology of an actual broken wire;
FIG. 3 is a scanning electron micrograph (2000 times magnification) of the fracture morphology of an actual broken wire;
FIG. 4 is a transmission electron micrograph of the fracture morphology of an actual broken wire (magnification 24000);
FIG. 5 is a transmission electron micrograph (magnification 18000) of the fracture morphology of an actual broken wire.
Detailed Description
The invention is further described with reference to the following figures and specific examples.
Example 1
Taking a certain fused transformer copper conductor as an example, the steps for finding out the operating parameters when the fused transformer copper conductor is fused are as follows:
(1) actual broken wire sampling: finding two copper conductors which are cut into two parts from power transmission and transformation equipment with faults, taking samples with the length of 10mm from the fracture point along the length direction of the copper conductors respectively, and taking samples while paying attention to the fact that the fracture is not damaged, wherein one sample is marked as A and is used for metallographic analysis; the other sample, labeled B, was used for microscopic analysis;
(2) preparation of high-temperature simulation sample: selecting a lead wire which is the same as the broken copper lead wire, processing the lead wire into a tensile sample, and performing a Gleeble tensile test;
(3) gleeble tensile experiments at different temperatures: adopting a Gleeble3800 thermal simulation experiment machine, setting the experiment temperature to be 100 ℃, 150 ℃, 200 ℃ and 250 ℃, respectively, and performing a group of stretching experiments on 3 high-temperature simulation samples at each temperature to obtain a relation curve of displacement and stretching force at each experiment temperature; the high-temperature simulation sample after the fracture is divided into two parts, wherein one part is marked as A 'for metallographic analysis, and the other part is marked as B' for microscopic analysis;
(4) metallographic structure analysis: selecting a part A' of a high-temperature simulation sample subjected to tensile fracture in a Gleeble tensile experiment, performing a metallographic analysis test, recording a metallographic structure, performing metallographic analysis on the part A of the actual fractured lead (fig. 1 is a metallographic structure morphology graph of the actual fractured lead), and comparing the morphology of the overheated structure of the part A; determining a simulated sample which is approximately the same as the actual fracture lead metallographic structure as a 250 ℃ snap sample;
the metallographic analysis test comprises the following specific operations: cutting the fracture along the longitudinal direction, then sequentially grinding with 200#, 500#, 800#, 1000# and 2000# dry-wet dual-purpose metallographic abrasive paper, when no large scratch is observed under a microscope, polishing the test block by using a polishing machine, firstly polishing by using coarse polishing cloth and polishing paste with larger abrasive particle size in the polishing process, and when the plane obtained by polishing is smoother, replacing the fine polishing cloth and the polishing paste (W1) with small abrasive particle size to polish the test sample; after polishing, the sample is washed by clean water and alcohol in sequence and 5 percent FeCl is used3Hydrochloric acid ethanol solution (5 gFeCl)3+15ml HCl+80ml CH3CH2OH) corroding the surface of a sample to be observed for about 10 seconds, washing the surface of the sample with alcohol, drying the surface of the sample with a blower, and then adopting a universal metallographic microscope(Olympus-PMG3, Olympus-GX71) for tissue visualization.
(5) Scanning electron microscope analysis: performing scanning electron microscope analysis on the fracture morphology of the simulated sample of the Gleeble tensile test at different temperatures and the fracture morphology of the actual broken lead, wherein the scanning electron microscope images of the fracture morphology of the actual broken lead are shown in figures 2 and 3 (the magnification of figure 2 is 500 times, and the magnification of figure 3 is 2000 times), and determining that the simulated sample similar to the fracture morphology of the actual broken lead is a 250-DEG C tensile breaking sample;
(6) transmission electron microscopy analysis: preparing a TEM sample from a part B' and a part B of a high-temperature simulation sample after being fractured in a Gleeble tensile experiment, observing the TEM sample under a transmission electron microscope, analyzing the dislocation density at the fracture, and judging the sample which is closest to the fracture of the actual fractured wire and is fractured at 250 ℃ according to the TEM image, wherein the images in FIGS. 4 and 5 are transmission electron microscope images of fracture appearance of the actual fractured wire (FIG. 4 is an HAADF image with the magnification of 24000 in a scanning transmission mode, and FIG. 5 is a bright field image with the magnification of 18000 in a transmission mode);
(7) determination of the operating parameters at break: finding out a simulation sample which is most similar to the fracture metallographic structure, the fracture morphology and the dislocation density of the actual fracture lead, finding out that a scanning electron microscope image of the fracture morphology and a transmission electron microscope image of the fracture morphology of the simulation sample at 250 ℃ are most similar to those of the actual fracture lead through experiments, preliminarily judging that the fracture copper lead is broken at 250 ℃, determining that the maximum tensile force in the fracture process is 17.1228kgf according to a tensile displacement curve of the copper lead at 250 ℃, and determining that the displacement of the copper lead in the fracture process is 9.6738 mm.
Claims (5)
1. A method for testing operation parameters of power transmission and transformation equipment when a copper conductor is broken is characterized by comprising the following steps:
(1) actual broken wire sampling: finding two copper conductors which are cut into two parts from power transmission and transformation equipment with faults, taking samples with the length of 10mm from the fracture point along the length direction of the copper conductors respectively, and taking samples while paying attention to the fact that the fracture is not damaged, wherein one sample is marked as A and is used for metallographic analysis; the other sample, labeled B, was used for microscopic analysis;
(2) preparation of high-temperature simulation sample: selecting a lead wire which is the same as the broken copper lead wire, processing the lead wire into a tensile sample, and performing a Gleeble tensile test;
(3) gleeble tensile experiments at different temperatures: adopting a Gleeble3800 thermal simulation experiment machine, setting the experiment temperatures to be 100 ℃, 150 ℃, 200 ℃ and 250 ℃, respectively, and performing a group of stretching experiments on 3-5 high-temperature simulation samples at each temperature to obtain a relation curve of displacement and stretching force at each experiment temperature; the high-temperature simulation sample after the fracture is divided into two parts, wherein one part is marked as A 'for metallographic analysis, and the other part is marked as B' for microscopic analysis;
(4) metallographic structure analysis: selecting a part A' of a high-temperature simulation sample subjected to tensile fracture in a Gleeble tensile test, performing a metallographic analysis test, recording a metallographic structure, and performing metallographic analysis on the part A of the actually fractured lead to compare the appearance of the overheated structure; determining a simulated sample with the same metallographic structure as the actual fracture lead;
(5) scanning electron microscope analysis: carrying out scanning electron microscope analysis on fracture morphology of a simulation sample of a Gleeble tensile test at different temperatures and fracture morphology of an actually fractured lead, and finding out a simulation sample which is similar to the fracture morphology of the actually fractured lead;
(6) transmission electron microscopy analysis: preparing a high-temperature simulation sample B' part after being pulled off in a Gleeble tensile experiment and a part B of an actual broken lead into TEM samples, observing under a transmission electron microscope, analyzing the dislocation density at a fracture, and judging the simulation sample which is closest to the actual broken lead fracture according to a TEM image;
(7) determination of the operating parameters at break: finding out a simulation sample which is closest to the fracture metallographic structure, the fracture morphology and the dislocation density of the actual fractured conductor, and determining the magnitude and the temperature of the electric force borne by the actual conductor when the fracture occurs according to the test parameters of the simulation sample.
2. The method for testing the operation parameters of the power transmission and transformation equipment during the copper conductor fracture as claimed in claim 1, wherein in the step (3), during the Gleeble tensile test, each group of simulation samples is controlled within 300 seconds according to a temperature rise-heat preservation program.
3. The method for testing the operation parameters of the power transmission and transformation equipment when the copper conductor is broken as claimed in claim 1, wherein in the step (3), when a Gleeble tensile test is performed, the tensile rate is 2.5 mm/min.
4. The method for testing operating parameters of an electric transmission and transformation equipment when a copper conductor is broken as recited in claim 1, wherein in the step (6), the preparing of the TEM sample comprises the steps of cutting, mechanical thinning, punching, mechanical thinning, pitting and ion thinning.
5. The method for testing the operation parameters of the power transmission and transformation equipment during the copper conductor fracture as recited in claim 1, 2, 3 or 4, characterized in that in the step (7), in the process of finding out the simulation sample which is the closest to the actual fracture metallographic structure, fracture morphology and dislocation density of the fracture of the broken conductor, two simulation samples which are closer to the actual fracture metallographic structure, fracture morphology and dislocation density of the fracture of the broken conductor are determined, the temperature ranges corresponding to the tensile tests of the two simulation samples are further divided into small intervals, and the experimental operations in the steps (3), (4), (5) and (6) are repeated, so that the simulation sample which is the closest to the actual fracture metallographic structure, fracture morphology and dislocation density of the fracture of the broken conductor is determined.
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| CN110794256A (en) * | 2019-09-26 | 2020-02-14 | 广西电网有限责任公司电力科学研究院 | Analysis method for high-temperature fusing of transmission conductor in operation process |
| CN112415170A (en) * | 2020-11-13 | 2021-02-26 | 吉林省电力科学研究院有限公司 | Method for evaluating service life of main steam pipeline of large heat supply unit |
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