CN111725771A - Fold line shape design of end part of 220kV metal type high-voltage cable joint explosion-proof device - Google Patents
Fold line shape design of end part of 220kV metal type high-voltage cable joint explosion-proof device Download PDFInfo
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- CN111725771A CN111725771A CN201911263243.3A CN201911263243A CN111725771A CN 111725771 A CN111725771 A CN 111725771A CN 201911263243 A CN201911263243 A CN 201911263243A CN 111725771 A CN111725771 A CN 111725771A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G15/00—Cable fittings
- H02G15/02—Cable terminations
- H02G15/06—Cable terminating boxes, frames or other structures
- H02G15/064—Cable terminating boxes, frames or other structures with devices for relieving electrical stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/14—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force of explosions; for measuring the energy of projectiles
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Abstract
The invention discloses a fold line design of an explosion-proof device end part of a 220kV metal type high-voltage cable joint, which comprises the following steps: by optimizing the fold line deflection angle and the size of the flange, the stress distribution of the end part of the protection device is balanced. The stress borne by the inner wall of the end part of the explosion-proof shell of the 220kV metal type high-voltage cable connector in different structures is calculated by utilizing a finite element calculation method based on the principle of electromagnetic-thermal and stress field coupling. The change relation between different deflection angles and the maximum stress value is obtained through simulation calculation, and the 220kV metal type high-voltage cable joint explosion-proof device end part broken line deflection angle is 60 degrees by combining the practicability and the economy of the protection device; the height and the thickness of the flange are optimized at the joint of the end head and the shell, so that the stress distribution at the vertex of the broken line of the end head is balanced, and the height and the thickness of the flange which are optimized are respectively 20mm and 50mm through simulation calculation. According to the invention, by comparing the broken line type end structure with the radian type end structure, the broken line type end structure has better economic benefit under the same technical condition.
Description
Technical Field
The invention relates to the field of 220kV high-voltage cable joint protection, in particular to a fold line design of a 220kV metal type high-voltage cable joint protection device end part.
Background
Due to the complex structure, the on-site installation is needed and the installation process is uneven, so that the high-voltage cable joint becomes a weak link for the operation of the high-voltage power cable. Statistically, more than 70% of cable failures occur at the joint. When the high-voltage cable joint has insulation breakdown fault, the electric arc releases huge energy in the insulation breakdown channel, so that the cable joint is burnt and exploded. The shock wave or fragments released by the explosion of the cable joint can cause great damage to other surrounding electric power facilities and operation and maintenance personnel. Therefore, an explosion-proof device needs to be additionally installed at the high-voltage cable joint to avoid secondary damage caused by explosion of the cable joint.
At present, a series of explosion-proof devices for high-voltage cable joints are developed in the market to reduce the harm caused by the explosion accident. However, these explosion-proof devices have a problem of internal pressure imbalance, particularly at the end portions thereof. When the cable joint explodes, the impact force distribution generated by huge electric arc energy to the inside of the protection device generates distortion at the end head, so that the impact stress born by certain parts of the end head is far greater than other parts, the end head part is more easily exploded, and the explosion-proof effect of the protection device is influenced. The test results of the common cable joint explosion-proof shell in the existing market show that after the cable joint explodes, the main body part of the joint protection device is still complete, the end part is seriously damaged, and fragments splash. Therefore, the shape of the end of the explosion-proof device needs to be designed reasonably to balance the impact stress inside the device during explosion.
Due to the energy of the short-circuit arc is larger, a metal shell (mostly aluminum-magnesium alloy) is generally adopted for the high-voltage cable joint explosion-proof device with the transmission voltage class, and the metal shell is of a sectional structure, namely comprises a middle body part and end parts at two ends. At present, the end part structure of the explosion-proof device of the high-voltage cable joint is mostly designed only by the experience of manufacturers, and no measure for balancing the pressure distribution of the shock waves on the inner wall of the end part is provided. The end part of the explosion-proof device is usually required to be increased in thickness to achieve the explosion-proof effect. The adoption of the end shape with a certain bending radian is an effective method for balancing the internal stress distribution of the device. However, for the explosion-proof device of the high-voltage cable joint, the adoption of the radian design can obviously increase the difficulty degree and the manufacturing cost in the processing process. In addition, the radian design increases the length of the end part, and the practical installation condition of the explosion-proof device is possibly limited, so that the feasibility is low.
From the above analysis, the arc design of the end part has problems in processing, use and cost; the dogleg design necessarily has a vertex where the pressure distribution is concentrated. However, the flange connection at the vertex of the break angle is equivalent to local structural reinforcement, so that the stress value at the point is reduced. Therefore, through the design of the deflection angle of the fold line at the end part and the height and the wall thickness of the flange connected with the protection device body, the problem that the pressure distribution of the inner wall is concentrated at the fold angle in the fold line type design can be solved.
Disclosure of Invention
The invention provides a fold design of a 220kV metal type high-voltage cable joint protection device end part, which is used for solving the problems of processing, use and cost of the arc design of the end part of the existing 220kV high-voltage cable joint protection device and the problem that the stress distribution of the inner wall of the fold design is concentrated at a fold angle.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a220 kV metal type high tension cable connects zigzag structure at protection device end position, includes:
in the 220kV high-voltage cable joint explosion-proof device, a broken line-shaped structure with a deflection angle is selected at the end part of the device, and the vertex of the broken angle is connected by a flange, which is equivalent to that the structure is locally reinforced, so that the stress distortion degree at the vertex is reduced.
Preferably, when the 220kV metal type high-voltage cable joint has a fault, energy released by the short-circuit arc acts on the explosion-proof shell through airflow to generate stress on the shell, and the position where the maximum stress value and the most obvious stress distortion occur on the inner wall of the explosion-proof shell is the connecting position of the end of the protection device and the body, namely the vertex of the bending angle.
Preferably, stress distribution of the end part of the explosion-proof device of the 220kV metal type high-voltage cable joint is calculated, a simulation model of the explosion process of the explosion-proof device of the 220kV metal type high-voltage cable joint is established by adopting finite element software, and impact stress distribution of explosion shock waves generated by short-circuit electric arcs on the explosion-proof device is calculated by the principle of thermal-fluid-stress multi-physical field coupling, so that the maximum stress value and the average stress value of the shell are obtained.
Preferably, the maximum stress value experienced at the vertex of the fold angle can be changed by choosing the most suitable fold line deflection angle α.
Preferably, the stress borne by the shell of the explosion-proof device of the 220kV metal type high-voltage cable connector is related to the impact force of airflow, and the thickened flange is adopted at the vertex of the broken line of the shell, so that the effect of relieving the stress distribution in the shell can be achieved.
Preferably, the fold line deflection angles of different end parts and the thickness h and the height L of the flange connected with the protection device body are designed, and the optimal fold line deflection angles, the thickness of the flange and the height value are obtained through simulation calculation.
Preferably, the bending line deflection angle of the end structure of the 220kV metal type high-voltage cable joint explosion-proof device is determined to be 60 degrees, the thickness of the connecting flange at the vertex of the bending line is determined to be 20mm, the height of the connecting flange is 50mm, and the stress distortion coefficient k in the cavity is reduced to 1.48.
The invention has the following beneficial effects:
according to the zigzag structure of the end part of the 220kV metal type high-voltage cable joint protection device, the stress distortion coefficient of the inner wall of the protection device can be reduced to 1.48 from 4.72 of the initial state by comparing the initial and optimized zigzag end part with the radian type end structure, and the optimized zigzag end part is considered to have a lower stress distortion coefficient and has better explosion-proof performance; under the same technical conditions, the optimized fold line-shaped end head structure has better economic benefit.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a diagram of the coupling between multiple physical fields in accordance with a preferred embodiment of the present invention;
FIG. 2 is a diagram of a simulation model of a high voltage cable joint protection device according to a preferred embodiment of the present invention;
FIG. 3 is a view of a dog-leg end of the high voltage cable splice protection device of the preferred embodiment of the present invention;
FIG. 4 is a schematic diagram of the stress distribution of the three-dimensional protective device according to the preferred embodiment of the invention;
FIG. 5 is a pictorial view of a protective device in accordance with a preferred embodiment of the present invention;
FIG. 6 is a diagram illustrating a process of changing air pressure at the upper cover plate of the energy release hole of the explosion-proof device according to the preferred embodiment of the invention;
FIG. 7 is a graph of the relationship between the deflection angle of the broken line at the end of the explosion-proof device and the maximum stress value in accordance with the preferred embodiment of the present invention;
FIG. 8 is a graph of stress characteristic values for the lower end-of-head portions of different flange configurations in accordance with a preferred embodiment of the present invention;
FIG. 9 is a block diagram of a dog-leg tip of the preferred embodiment of the present invention;
fig. 10 is a schematic pre-detonation view of a high-voltage cable joint protection arrangement in accordance with a preferred embodiment of the present invention;
FIG. 11 is a schematic and pictorial illustration of a strain gage installation in accordance with a preferred embodiment of the present invention;
FIG. 12 is a graph of a typical strain waveform measured during the test and the test of the preferred embodiment of the present invention;
FIG. 13 is a view of a curved end of the preferred embodiment of the present invention;
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
Referring to fig. 1, the core of the problem of explosion caused by short-circuit arc of the cable joint is the interaction result of a temperature field, a fluid field and a stress field, and the temperature rise caused by arc explosion is followed by gas expansion to impact an explosion-proof shell, so that stress is generated on the shell, and the action relationship of coupling among multiple physical fields in cable joint simulation is summarized through analysis.
According to related documents at home and abroad and geometric parameters of all parts of a 220kV XLPE insulated high-voltage AC cable accessory in engineering, a two-dimensional axisymmetric simulation model is established in COMSOLULTIPhysics simulation software according to a ratio of 1:1 by referring to the original model of accessories produced by domestic accessory manufacturers and the electric field strength born by the materials, the metal type explosion-proof device is made of 5 series aluminum-magnesium alloy materials, the length of the explosion-proof device is 2200mm, the thickness of the inner wall is 460mm, and the wall thickness is 8mm, and the equivalent heat loss of a large-current arc of the 220kV high-voltage cable connector due to insulation breakdown is obtained in the early-stage research simulation, so that the arc generated by the insulation breakdown of the 220kV high-voltage cable connector is equivalent to a heat source sphere with the radius of 4.4mm, the heat loss density of the arc is 7 × 1015W/m3. Because the stress distribution of the end part is researched, the energy leakage hole on the shell is omitted during model building, and the two-dimensional axisymmetric model is built.
Referring to fig. 3 and 4, the most obvious position of stress distortion of the inner wall of the explosion-proof shell is the connecting position of the end head of the protection device and the body, namely a connecting point M. The maximum stress value PM, which reaches 33296N/M, also occurs at the connection point M2. Through simulation calculation, the average stress value P of the explosion-proof shellavgSimilar to the stress value occurring at point N in fig. 4, it is therefore considered that the average stress value of the explosion-proof housing, average stress value P, can be reflected by the stress value of the end point location near the cable exitavgIs 7051N/m2. Maximum stress value PMAnd average stress value P of shellavgThe ratio is defined as the distortion coefficient k of stress, and the stress distortion coefficient k of the explosion-proof shell is 4.72. To reduce stressDistortion coefficient, the fold line structure needs to be developed and optimally designed.
1. Fold line shape design of end part of 220kV cable joint explosion-proof shell
1.1 optimization design method of fold line-shaped explosion-proof shell end structure
On the basis of analyzing the structural characteristics of the explosion-proof device of the 220kV high-voltage cable connector and the stress variation characteristics borne by the shell, the fold line-shaped design for optimizing the stress distribution of the end part is provided aiming at the problem of stress concentration of the end fold line structure at the fold angle. The design points and design methods are as follows:
(1) the deflection angle alpha of the broken line at the end part of the explosion-proof device.
Obtaining the stress distribution of the inner wall of the end part of the explosion-proof device under the same arc energy by selecting different fold line angles alpha according to a finite element simulation method of multi-physical field coupling, and extracting the maximum stress value of the stress distribution; obtaining a relation curve of the deflection angle and the maximum stress value of the end part of the explosion-proof shell through data processing; and obtaining the optimized deflection angle alpha by integrating the stress distribution result of the shell and the actual condition requirements.
(2) The thickness h and the width L of the flange of the end part of the explosion-proof device and the middle shell at the connecting point M.
A thickened flange is adopted at the connecting point M, so that the stress concentration phenomenon at the connecting point M can be effectively relieved. Because the explosion-proof device adopts a sectional type structure, under the actual structure, the body flange and the end flange at the connecting point M are connected through bolts. Under the condition of ensuring enough bolt connection strength, 2 flanges can be taken as a whole in the simulation.
Aiming at the structure of the connecting flange, respectively simulating by designing different flange thicknesses h and widths L; and obtaining the maximum stress value (at the connecting point M) of the end part and the average stress value of the inner wall of the end part, thereby selecting the flange structure which ensures the most balanced stress distribution.
At present, metal type explosion-proof devices are all provided with energy release holes and corresponding opening modes. Taking a double-side open type explosion-proof device as an example, the project group is designed with a spring tension type energy release hole, as shown in fig. 5.
The cover plate of the energy discharge hole is tensioned by a spring, and the functions of preventing water and reducing explosive splashed objects are achieved. When short-circuit electric arcs appear and the internal pressure of the protection device reaches a certain degree, the cover plate of the spring tension type energy release hole is flushed away, the energy release hole starts to play an energy release role, and the internal pressure of the device is reduced. Through simulation calculation, the change relationship of the gas pressure at the upper cover plate of the cavity energy release hole along with time after the short-circuit arc of the cable joint appears is shown in fig. 6. As can be seen from fig. 6, when t is 40ms, the cover plate of the spring-tensioned vent hole of the protection device is pushed open, the vent hole starts to perform the venting function, and the internal pressure of the device rapidly drops. I.e. the gas pressure in the housing reaches a maximum until the energy release hole is flushed away. In order to leave a certain margin, the time for keeping the shell sealed is set to be 70ms, namely, the stress value on the shell of the protection device when the simulation time point is t equal to 70ms is taken as the basis of the design of the device.
1.2 determination of deflection angle alpha at end of explosion-proof device
By selecting different fold line deflection angles alpha and when no flange is added at the connecting point M, the stress distribution of the inner wall of the end part of the explosion-proof device under the same electric arc energy is calculated according to a finite element simulation method of multi-physical-field coupling, and the maximum stress value of the explosion-proof device is extracted. From the simulation results, the maximum stress occurs at the connection point M. The graph of the relationship between the different fold line deflection angles alpha and the maximum stress value (stress value at the connecting point M) of the end part of the explosion-proof device obtained by simulation is shown in FIG. 7. As can be seen from fig. 7, the maximum stress value P is smaller as the folding angle α of the explosion-proof device end portion is larger. (1) When the folding line deflection angle alpha is less than 60 degrees, the maximum stress P is reduced along with the increase of alpha, and the reduction rate is obvious; (2) when the fold line deflection angle alpha is larger than 60 degrees, the maximum stress P is also reduced along with the increasing of the alpha, but the reduction speed is slow.
According to the simulation result, when the deflection angle α is 55 degrees, 60 degrees and 65 degrees respectively, the maximum stress value of the end part is 31948N/m respectively2，24584N/m2And 23776N/m2It can be seen that the maximum stress value is reduced by 23% for a deflection angle α of 60 ° relative to a deflection angle α of 55 °, the deflection angle being such thatThe maximum stress value at 65 ° for α dropped only 25.6%, indicating that the effect of the α increase on improving the stress distribution would be very insignificant when the fold offset angle α was greater than 60 °.
On the other hand, the end portion should not be designed to be too long in view of practical application conditions and manufacturing cost of the high-voltage cable connector. The greater the fold line deflection angle α, the longer the length of the end portion needs to be. Therefore, by comprehensively considering the practicability, safety and economy of the protection device, the folding line deflection angle alpha of the finally selected end part is 60 degrees.
1.3 structural design of end and body connecting flange
In practical application, when the wall thickness of the explosion-proof device of the 220kV cable joint is 8mm, the thickness h of the connecting flange is usually between 15 and 20mm, and the width L of the connecting flange is usually between 40 and 50 mm. For the best results in reducing the casing stresses, five typical flange sizes were selected in the simulation and calculated, flange 1 (L40 mm, h 15mm), flange 2 (L42.5 mm, h 16.25mm), flange 3 (L45 mm, h 17.5mm), flange 4 (L47.5 mm, h 18.75mm) and flange 5 (L50 mm, h 20 mm).
When t is 70ms, the maximum stress value P of the end part corresponding to the flanges with different sizes is obtained by calculating according to the simulation method provided by the text when the broken line deflection angle α is 60 degreesMAnd average stress value P of shellavgAs shown in fig. 8. As can be seen from fig. 8, the larger the flange size is, the smaller the stress maximum value PM at the end portion of the explosion-proof device is, and the average stress value of the housing is substantially constant. The ratio of the maximum stress value PM to the average stress value Pavg of the housing is defined as the distortion coefficient k of the stress, and the k values corresponding to the flanges with different sizes are shown in table 1.
TABLE 1 stress characteristic values for different sized flanges
As can be seen from table 1, when the flange 5 (L50 mm, h 20mm) is selected, the distortion coefficient k of the stress is 1.48, which is the minimum value. Therefore, the final flange thickness h is 20mm and the final flange width L is 50 mm.
1.4220 kV high tension cable connects explosion-proof equipment broken line type end optimization structure
Through the deflection angle of the broken line and the design of the flange, the optimized structure of the broken line type end head of the explosion-proof device of the 220kV high-voltage cable joint is finally determined as shown in fig. 9.
The finally adopted end structure is that the deflection angle of the fold line is 60 degrees, the connecting flange at the vertex of the fold line is 20mm thick and 50mm high. The stress distortion coefficient k in the cavity is reduced to 1.48.
Explosion stress test of 2220 kV metal type high tension cable joint protection device broken line type end design
2.1 test apparatus and test method
In order to check whether the fold line-shaped optimized design of the 220kV high-voltage cable joint protection device is reasonable, the end part structure designed according to the figure 9 is processed. The 220kV high-voltage cable joint protection device is made of 5-series aluminum-magnesium alloy materials, and a 220kV cable with a section of 2500mm2 and a complete set of cable joint device are arranged in the protection device. The test site layout is shown in fig. 10. And (4) testing the pressure distribution of the end part, namely measuring the impact stress on the shell by adopting explosive blasting. The test is carried out in the field test field of Xuyi 925 factory, Jiangsu. 100g of bulk 8701 explosive is used as a test explosive source. The test adopts the strain gauge to measure the dynamic strain generated by the protection device under the action of explosion, and utilizes the piezoelectric shock wave pressure sensor to measure the pressure of the shock wave generated by explosion. The schematic diagram and the real diagram of the strain flower installation are shown in fig. 11. Point 1 is the maximum stress distribution position of the shell, and point 2 is the average stress distribution position of the shell.
2.2 test procedures and results
The phenomena observed on the high-voltage cable protection device blasting test site are mainly as follows: under the action of 100g8701 explosive, the protection device can discharge energy normally, and the shell is not damaged after the explosion shock wave passes. The experimental procedure and experimental measurements of typical strain waveforms taken with a high speed camera are shown in fig. 12. Generally, the strain gauge can measure the strain of the stressed part to be measured in three directions. Therefore, the stress results of the explosive impact of 100g8701 measured on the points 1 and 2 on the shell and the stress distortion coefficient k calculated are shown in table 2.
TABLE 2 typical point location strain test results of the ends
| Measuring point location | Axial strain (P)a) | Hoop strain (P)a) | Inclined 45 deg. direction (P)a) |
| 1 | 3502.33 | 11271.65 | 466.71 |
| 2 | 2350.56 | 7773.55 | 317.49 |
| Distortion coefficient k | 1.49 | 1.45 | 1.47 |
As can be seen from the data in Table 2, the stress distortion coefficient obtained by the test is basically consistent with the simulation result after the zigzag-shaped end head structure designed by the invention is adopted. The invention proves that the optimized fold line-shaped design of the end part of the 220kV high-voltage cable joint protection device is reliable.
3 comparison of technical and economic benefits
3.1 technical-economic comparison of optimized dog-leg ends with initial dog-leg ends
Calculated according to the initial end design of the 220kV high-voltage cable joint protection device (deflection angle alpha is 45 degrees, L at the connecting flange is 40mm, and h is 15mm), the stress distortion coefficient of the shell is 4.72 according to the result obtained in section 1.1. The optimized end design of the 220kV high-voltage cable joint protection device (the deflection angle alpha is 60 degrees, the L at the connecting flange is 50mm, and the h is 20mm) and the stress distortion coefficient of the shell is 1.48. It can be seen that the explosion-proof performance of the technically optimized tip design is significantly improved.
In the aspect of economy, the length of the end part contraction part of the initial structure is 76mm shorter than the optimized length, and the length is extremely small relative to the length of the body of the 220kV high-voltage cable joint protection device (the distance between end flanges on two sides, which is 2600mm in the design); the dimensions of the connecting flanges vary slightly. Therefore, the end head structure of the initial structure has no great advantage in economic cost, but the explosion-proof performance of the optimized end head structure is obviously improved. Therefore, the optimized end head structure has obvious comprehensive technical and economic advantages.
3.2 optimization of the cost-effective comparison of the fold-line and arc end structures
Compared with the broken line type design, the radian type design of the end part of the protection device is characterized in that the connecting point M is designed to be in an arc shape. The radian-type end head structure given in the document 'the optimized design of the end head part structure of the high-voltage cable joint explosion-proof device based on multi-physical field coupling' is shown in fig. 13, and if the end head structure is designed into a radian structure at a connecting point M, the key point is to determine the optimal curvature radius of the radian. At the moment, the end flange and the body flange are in straight butt joint, so that the problem of angle does not exist, and the problem of stress distortion does not exist at the joint of the flanges. It is found by calculation that when the radius of curvature is greater than 0.3m, the maximum stress value of the inner wall of the cavity is decreased to an extremely small extent. Therefore, the radius of curvature of the tip portion is 0.3 m.
For further comparative analysis, the maximum stress value, the average stress value and the stress distortion coefficient k of the inner wall of the cavity of the protection device under different arc curvature radii are calculated according to the models and parameters shown in the above documents, and the calculation results are shown in table 2.
TABLE 3 stress characteristic values corresponding to arcs of different curvature radii
As can be seen from the data in Table 2, when the arc structure with a radius of curvature of 0.3M is adopted at the connection point M, the stress distortion coefficient k of the inner wall of the cavity is reduced to 1.42. The decrease in distortion coefficient k is not significant as the radius of curvature continues to increase.
Comparing the data in table 1 and table 3, it can be seen that the maximum stress value, the average stress value and the stress distortion coefficient of the inner wall of the cavity are similar to those of the optimized broken line type structure, and the same effect is achieved technically.
However, comparing the broken line type end structure and the arc type end structure shown in fig. 9 and fig. 13, it can be obtained that (1) under the same protection device body, end contraction caliber (200mm) and end part wall thickness (8mm), the length of the broken line type end is 225.17mm, the length of the arc type end is 338.95mm, the arc type end is 50.53% longer than the broken line type end, and the material consumption is increased; (2) when the end part is designed to be in a radian shape, the difficulty and the cost of processing and manufacturing can be obviously increased. Therefore, from the economic benefit analysis, the broken line type end head designed by the method has better economic benefit.
In conclusion, the broken line deflection angle alpha of the end part position selected by the broken line-shaped end structure is 60 degrees, and the flange (L is 50mm, and h is 20mm) is additionally arranged at the joint of the end and the shell, so that the stress distortion coefficient of the inner wall of the protection device can be reduced to 1.48, and the stress borne by the shell is effectively reduced. The stress change condition generated at the end part in the explosion process is tested and established through the explosion test, and the test result shows that the adopted fold line-shaped end is accurate and reliable in optimized design. By comparing the initial and optimized fold-line-shaped end structure with the radian-type end structure, the optimized fold-line-shaped end part has a lower stress distortion coefficient and better explosion-proof performance, and the optimized fold-line-shaped end structure has better economic benefit under the same technical condition.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. The utility model provides a zigzag structural design at 220kV metal type high tension cable connects explosion-proof equipment tip position which characterized in that includes:
when the 220kV metal type high-voltage cable connector fails, energy released by short-circuit electric arc acts on the explosion-proof shell through airflow to generate stress on the shell, and the position where the maximum stress value and the most obvious stress distortion occur on the inner wall of the explosion-proof shell is the connecting position of the end of the protection device and the body, namely the vertex of the break angle. In the 220kV high-voltage cable joint explosion-proof device, the end part of the device is optimally selected to be a zigzag structure with a specific deflection angle, and a flange with an optimized size is adopted at the joint of the end and the body (the vertex of the deflection angle) for connection, so that the stress distortion degree at the vertex is relieved.
2. The stress distortion degree of the end part of the 220kV metal type high-voltage cable joint explosion-proof device according to claim 1, wherein a simulation model of the explosion process of the 220kV metal type high-voltage cable joint explosion-proof device is established by adopting finite element software, and the impact stress generated on the explosion-proof device by the explosion shock wave generated by the short-circuit arc is calculated by the principle of thermal-fluid-stress multi-physical field coupling, so that the ratio of the maximum stress value of the shell to the average stress value of the shell is obtained, and the ratio is called as the stress distortion coefficient.
3. The broken line structure at the end part of the 220kV metal type high-voltage cable joint explosion-proof device according to claim 1, wherein the stress borne by the shell has reasonable broken line deflection angle at the end part, except for the relationship between the airflow impact force and the shell material and the local thickness, and the effect of balancing the stress distribution in the shell can be achieved.
4. The design of the deflection angle of the broken line-shaped structure at the end part of the 220kV metal type high-voltage cable joint explosion-proof device according to claim 3, wherein the stress distribution of the inner wall of the end part of the explosion-proof device is obtained under the same electric arc energy by selecting different broken line angles alpha according to a finite element simulation method of multi-physical-field coupling, and the maximum stress value of the stress distribution is extracted; and obtaining a relation curve of the deflection angle and the maximum stress value of the end part of the explosion-proof shell through data processing. And selecting the optimized deflection angle alpha by combining economic and practical indexes.
5. The optimized design of the connecting flange with the zigzag structure at the end part of the 220kV metal type high-voltage cable joint explosion-proof device according to claim 1, wherein the flange structure can be simulated by setting different flange thicknesses h and widths L; and obtaining the maximum stress value of the connecting part of the end head of the protection device and the body and the average stress value of the inner wall of the end part, and selecting the optimal flange thickness and width by taking the minimum stress distortion coefficient as an index.
6. The broken line structure at the end part of the 220kV metal type high-voltage cable joint explosion-proof device as claimed in claims 4 and 5, wherein the broken line deflection angle of the end structure is 60 degrees, the thickness of the connecting flange at the top point of the broken line is 20mm, the height of the connecting flange is 50mm, and the stress distortion coefficient in the cavity can be reduced to 1.48.
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| CN201911263243.3A Pending CN111725771A (en) | 2019-12-11 | 2019-12-11 | Fold line shape design of end part of 220kV metal type high-voltage cable joint explosion-proof device |
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| JPH07170640A (en) * | 1993-12-16 | 1995-07-04 | Showa Electric Wire & Cable Co Ltd | Cable terminal part |
| CN108631256A (en) * | 2018-07-04 | 2018-10-09 | 长沙理工大学 | Method for designing opening mode of energy discharge hole of explosion-proof device of high-voltage cable connector |
| CN109190277A (en) * | 2018-09-14 | 2019-01-11 | 广东电网有限责任公司 | High-voltage cable joint explosion-protection equipment lets out the emulation mode of energy hole opening radius |
| CN109408875A (en) * | 2018-09-14 | 2019-03-01 | 广东电网有限责任公司 | High-voltage cable joint explosion-protection equipment lets out the emulation mode of energy hole aperture position |
| CN109408874A (en) * | 2018-09-14 | 2019-03-01 | 广东电网有限责任公司 | The end position crooked radian emulation mode of high-voltage cable joint explosion-protection equipment |
| CN208638006U (en) * | 2018-08-31 | 2019-03-22 | 广东电网有限责任公司 | A kind of high-voltage cable joint armored cassette |
| CN110176744A (en) * | 2019-06-14 | 2019-08-27 | 广东安诺新材料科技有限公司 | High-voltage cable joint metal explosion-proof device and end head parameter determination method and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH07170640A (en) * | 1993-12-16 | 1995-07-04 | Showa Electric Wire & Cable Co Ltd | Cable terminal part |
| CN108631256A (en) * | 2018-07-04 | 2018-10-09 | 长沙理工大学 | Method for designing opening mode of energy discharge hole of explosion-proof device of high-voltage cable connector |
| CN208638006U (en) * | 2018-08-31 | 2019-03-22 | 广东电网有限责任公司 | A kind of high-voltage cable joint armored cassette |
| CN109190277A (en) * | 2018-09-14 | 2019-01-11 | 广东电网有限责任公司 | High-voltage cable joint explosion-protection equipment lets out the emulation mode of energy hole opening radius |
| CN109408875A (en) * | 2018-09-14 | 2019-03-01 | 广东电网有限责任公司 | High-voltage cable joint explosion-protection equipment lets out the emulation mode of energy hole aperture position |
| CN109408874A (en) * | 2018-09-14 | 2019-03-01 | 广东电网有限责任公司 | The end position crooked radian emulation mode of high-voltage cable joint explosion-protection equipment |
| CN110176744A (en) * | 2019-06-14 | 2019-08-27 | 广东安诺新材料科技有限公司 | High-voltage cable joint metal explosion-proof device and end head parameter determination method and system |
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Application publication date: 20200929 |