Electric tree experiment device and experiment method for solid medium constant-temperature wind heat

Abstract

The invention relates to an electrical tree experimental device and experimental method for solid medium constant-temperature wind heat, and the device comprises a pin electrical tree sample, a metal electrode pedestal, a lower electrode, a high-voltage lead-in port, an upper electrode, a needle-shaped metal high-voltage sleeve, an insulating support column, a constant-temperature wind heat device, an electrical tree detection device, and a metal housing. The left side and the right side between the upper electrode and the lower electrode are connected with each other through insulating support columns to form an experiment cavity; the high-voltage lead-in port is connected with the upper electrode, the contact pin electric tree sample is mounted at the top of the lower electrode through the metal electrode base, one end of the needle-shaped metal high-voltage sleeve is connected with the upper electrode, and the other end is detachably connected with the contact pin electric tree sample; the electric tree detection device and the constant-temperature air heating device are mounted in the experiment cavity; the lower electrode is connected with the inner bottom of the metal shell. Compared with the prior art, the environment of the solid medium under different temperatures and electric fields can be simulated more truly, so that the electric tree phenomenon is more realistic, and the experiment accuracy is improved.

Description

Technical Field

[0001] The invention relates to the field of electric tree branch experimental devices, in particular to an electric tree branch experimental device and an experimental method for constant temperature wind heating of solid media. Background Art

[0002] With the continuous development of power systems, solid dielectrics, especially cross-linked polyethylene materials, are being widely used in key links such as DC transmission and insulation. However, solid dielectrics often need to withstand harsh environments such as high temperature and high voltage during the operation of power equipment; as time goes by, the internal parts of solid insulating materials may have excessively high local electric fields due to defects in the production process, the influence of the external environment, or other factors, thus causing the growth of electrical dendrites.

[0003] The initiation and growth of electrical trees will cause the insulation performance of solid insulating materials to gradually decrease. When the electrical trees grow to a certain extent, they will cause insulation breakdown and eventually lead to equipment failure.

[0004] Studies have shown that the generation and development of electrical tree phenomena are closely related to the electric field strength, the characteristics of the medium itself, and the environment in which the medium is located. In particular, under different temperature conditions, there are significant differences in the growth rate and characteristics of electrical tree dendrites. Therefore, the study of the initiation and growth characteristics of electrical tree dendrites in solid media is particularly important. Most of the existing electrical tree dendrite experimental devices directly connect the two ends of the electrical tree dendrite sample to a high-voltage DC power supply for experiments. For example, the low-temperature electrical tree dendrite aging experimental device based on DC superimposed harmonics disclosed in the invention with publication number CN110057818A cannot truly simulate the environment under different temperatures and electric fields when the solid medium produces electrical tree dendrites. Summary of the invention

[0005] The purpose of the present invention is to provide an electrical tree experiment device and an experimental method for constant temperature wind heating of solid media in order to overcome the defect that the above-mentioned prior art cannot truly simulate the environment under different temperatures and electric fields when the electrical tree phenomenon occurs in the solid media.

[0006] The purpose of the present invention can be achieved by the following technical solutions: An electrical tree experiment device for constant temperature wind heating of solid medium, comprising a plug-in electrical tree specimen, a metal electrode base, a lower electrode, a high voltage introduction port, an upper electrode, a needle-shaped metal high voltage bushing, an insulating support column, a constant temperature wind heating device, an electrical tree detection device and a metal shell, wherein the left and right sides between the upper electrode and the lower electrode are interconnected through the insulating support column to form an experimental cavity; the high voltage introduction port is connected to the upper electrode, the plug-in electrical tree specimen is installed on the top of the lower electrode through the metal electrode base, one end of the needle-shaped metal high voltage bushing is connected to the upper electrode, and the other end is detachably connected to the plug-in electrical tree specimen; the electrical tree detection device is installed at the bottom of the upper electrode and directly faces the plug-in electrical tree specimen, and the constant temperature wind heating device is installed in the experimental cavity; The lower electrode is connected to the inner bottom of the metal shell. The metal shell is provided with a metal window facing the experimental cavity. The metal window is covered with an insulating and heat-insulating front plate.

[0007] Furthermore, the device also includes a sample fixing rolling belt, and a mounting groove is provided at the bottom of the metal electrode base. The sample fixing rolling belt passes through the outside of the pin electrical tree sample and the mounting groove of the metal electrode base to fix the pin electrical tree sample and the metal electrode base.

[0008] Furthermore, the needle-shaped metal high-voltage bushing is made of tungsten steel and has a needle-shaped discharge tip.

[0009] Furthermore, the insulating and heat-insulating front plate is made of polytetrafluoroethylene.

[0010] Furthermore, the electrical tree branch detection device detects the inside of the experimental chamber through ultrasonic waves, and automatically collects the electrical tree branch morphology when changes in the electrical tree branches are detected.

[0011] Furthermore, there are multiple constant temperature wind heating devices, which are respectively installed on the insulating support columns on both sides of the experimental chamber.

[0012] Furthermore, the constant temperature wind heating device includes a fan and a heating wire whose temperature can be controlled, and the fan is used to blow the stable hot air generated by the heating wire toward the pin-type electrical tree branch sample.

[0013] Furthermore, the device also includes a base, which is arranged below the lower electrode and is used to balance the lower electrode inside the metal shell.

[0014] Furthermore, the insulating and heat-insulating front plate is welded to the metal shell through a metal window.

[0015] The present invention also provides an experimental method based on the above-mentioned electric tree experiment device for constant temperature wind heating of solid medium, comprising the following steps: S1: Clean the surfaces of various components of the electric tree experiment device and check whether the lower electrode is well grounded; S2: Take out the integral connection device of the upper electrode and the lower electrode in the metal shell from the electrical tree test device, place the pin electrical tree sample to be tested on the metal electrode base, fix the pin electrical tree sample and the metal electrode base with a sample fixing rolling belt, put a needle-shaped metal high-voltage bushing on the needle electrode of the pin electrical tree sample, and then put the integral connection device of the upper electrode and the lower electrode back into the metal shell; S3: Check and determine whether the metal connection between the high voltage introduction port and the high voltage power supply is intact, and whether the grounding condition between the lower electrode and the metal shell is good; S4: Connect the various components of the constant temperature wind heating device through the air duct, and turn on the constant temperature wind heating device until the wind speed and temperature in the entire experimental chamber tend to be stable; S5: When the temperature in the entire experimental chamber rises to the preset temperature, the high-voltage power supply is started, and the growth of the electrical tree branches is experimentally recorded by the electrical tree branch detection device; after the recording is completed, the operation of the high-voltage power supply and the constant temperature wind heating device is stopped in sequence; S6: Repeat steps S2-S5 to test different plug-in electrical tree specimens until all preset experimental procedures are completed; S7: After the experimental procedures are all completed, disconnect the metal connecting wire from the high-voltage power supply, and when the circulating air in the constant temperature wind heating device drops to room temperature, clean the various components of the electrical tree experiment device for constant temperature wind heating of solid media, and end the experiment.

[0016] Compared with the prior art, the present invention has the following advantages: (1) The electric tree experiment device for constant temperature wind heating of solid medium of the present invention cleverly cooperates with the constant temperature wind heating device, the upper electrode, the lower electrode, the plug-in electric tree specimen and the needle-shaped metal high-voltage bushing. The constant temperature wind heating device provides a stable temperature environment for the plug-in electric tree specimen. The plug-in connection between the plug-in electric tree specimen and the needle-shaped metal high-voltage bushing can provide a precise and stable electric field strength at the discharge tip, more realistically simulating the environment of the solid medium under different temperatures and electric fields, thereby making the electric tree phenomenon on the sample more realistic and improving the accuracy of the measured results.

[0017] (2) The electric tree experiment device for constant temperature wind heating of solid media of the present invention can effectively reduce the influence of the flow of circulating insulating oil on the sample during the experiment by using a detachable cable tie to fix the plug-in electric tree test specimen and the metal electrode base, thereby making the sample replacement in the experiment more efficient. In addition, the thermal insulation front plate is made of polytetrafluoroethylene. This setting not only ensures the clarity of observation during the experiment, but also has a good insulation effect, which can effectively ensure the safety of the high-speed camera used for observation during the experiment.

[0018] (3) The electric tree tree experiment device for solid medium constant temperature wind heating of the present invention improves the complexity of the experiment process as a whole, simplifies the connection method between the sample and the electrode, and the form of the sleeve allows the sample to be inserted in advance. The presence of the rolling strip can effectively reduce the impact of the sample on the flow of circulating insulating oil during the experiment. In addition, the detachability of the device can be disassembled after the test to replace the sample, which to a certain extent reduces the time for the constant temperature wind heating machine to open and close the cooling and heating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the internal structure of an electric tree experiment device for constant temperature wind heating of a solid medium provided in an embodiment of the present invention; Figure 2 It is a schematic diagram of the overall structure of an electric tree experiment device for constant temperature wind heating of solid media provided in an embodiment of the present invention; 1. Pin-inserted electric tree specimen, 2. Specimen fixing strip, 3. Metal electrode base, 4. Lower electrode, 5. High voltage introduction port, 6. Upper electrode, 7. Needle-shaped metal high voltage bushing, 8. Insulating support column, 9. Constant temperature wind heating device, 10. Electric tree detection device, 11. Metal window, 12. Insulating and heat-insulating front plate, 13. Metal casing. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0023] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0024] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] Example 1 like Figure 1 As shown, the present embodiment provides an electrical tree experiment device for constant temperature wind heating of solid media, including a pin electrical tree sample 1, a metal electrode base 3, a lower electrode 4, a high voltage introduction port 5, an upper electrode 6, a needle-shaped metal high voltage bushing 7, an insulating support column 8, a constant temperature wind heating device 9, an electrical tree detection device 10 and a metal shell 13, the left and right sides between the upper electrode 6 and the lower electrode 4 are interconnected through the insulating support column 8 to form an experimental cavity; the high voltage introduction port 5 is connected to the upper electrode 6, the pin electrical tree sample 1 is installed on the top of the lower electrode 4 through the metal electrode base 3, one end of the needle-shaped metal high voltage bushing 7 is connected to the upper electrode 6, and the other end is detachably connected to the pin electrical tree sample 1; the electrical tree detection device 10 is installed at the bottom of the upper electrode 6 and is directly opposite to the pin electrical tree sample 1, and the constant temperature wind heating device 9 is installed in the experimental cavity, as shown in FIG. Figure 2 As shown; The lower electrode 4 is connected to the inner bottom of the metal shell 13 . The metal shell 13 is provided with a metal window 11 facing the experimental cavity. The metal window 11 is covered with an insulating and heat-insulating front plate 12 .

[0027] The insulating and heat-insulating front plate 12 is welded to the metal shell 13 through the metal window 11, thereby ensuring the sealing of the entire constant temperature wind heating device without affecting observation.

[0028] The electrical tree branch detection device 10 detects the inside of the experimental chamber through ultrasonic waves and collects the real-time electrical tree branch morphology. When the changes of the electrical tree branches are detected, the electrical tree branch morphology is automatically collected.

[0029] There are multiple constant temperature wind heating devices 9, which are respectively installed on the insulating support columns 8 on both sides of the experimental chamber. In this embodiment, a corresponding constant temperature wind heating device 9 is provided on both sides of the electric tree fixed structure. This arrangement facilitates the circulating wind heating mechanism to form a stable air path inside the metal shell 13, thereby ensuring that the solid electric tree sample is at a stable temperature and improving the accuracy of the results obtained by the solid dielectric electric tree experimental device.

[0030] The constant temperature wind heating device 9 includes a fan and a heating wire whose temperature can be controlled. The fan blows the stable hot air generated by the heating wire toward the pin-type electrical tree branch sample 1.

[0031] Preferably, the device also includes a sample fixing rolling belt 2, and a mounting groove is provided at the bottom of the metal electrode base 3. The sample fixing rolling belt 2 passes through the outside of the pin electrical tree sample 1 and the mounting groove of the metal electrode base 3 to fix the pin electrical tree sample 1 and the metal electrode base 3.

[0032] Preferably, the needle-shaped metal high-voltage bushing 7 is made of tungsten steel and has a needle-shaped discharge tip. Since tungsten steel has the characteristics of high hardness, corrosion resistance and wear resistance, this setting is convenient for improving the stability and durability of the needle-shaped metal high-voltage bushing 7 during the test, reducing the risk of errors in the experimental results caused by wear of the needle-shaped metal high-voltage bushing 7. In addition, during the test, the needle-shaped metal high-voltage bushing 7 can work with the lower electrode 4 to form a high-voltage to low-voltage DC voltage environment. This setting can also ensure that the electric field strength of the discharge tip of the needle-shaped metal high-voltage bushing 7 can accurately meet the requirements of the experiment, improve the flexibility of the test operation, and thus improve the accuracy of the results obtained by the electric tree test device for solid media.

[0033] Preferably, the lower electrode 4 and the upper electrode 6 are made of a low-resistance conductive material; the insulating and heat-insulating front plate 12 is made of polytetrafluoroethylene, polychlorotetrafluoroethylene (Polytetrafluoroethylene, abbreviated as PTFE), which is known for its excellent mechanical strength, electrical insulation performance, high resistance to acids and alkalis, and chemical stability. This arrangement ensures the necessary heat dissipation of the wind-removing heat trough part, and also realizes thermal isolation of the remaining parts, thereby effectively reducing errors in the test process and improving the accuracy and reliability of the test data.

[0034] Preferably, the device further comprises a base, which is arranged below the lower electrode 4 so that the entire Figure 1 The device shown is capable of balancing the Figure 2The interior of the device shown can also ensure that the device can remain stable in the circulating oil circuit formed by the circulating air heater, making it easier for experimenters to observe the samples.

[0035] Example 2 This embodiment provides an experimental method for an electric tree tree experimental device for constant temperature wind heating of a solid medium based on the embodiment 1, comprising the following steps: S1: cleaning the surfaces of various components of the electric tree experiment device, i.e., cleaning and wiping them to keep them clean, and checking whether the lower electrode 4 is well grounded; S2: Take out the integral connection device of the upper electrode 6 and the lower electrode 4 in the metal shell 13 from the electric tree experimental device, place the plug-in electric tree sample 1 to be tested on the metal electrode base 3, and fix the plug-in electric tree sample 1 and the metal electrode base 3 with the sample fixing rolling belt 2, put the needle-shaped metal high-voltage bushing 7 on the needle electrode of the plug-in electric tree sample 1, ensure that the needle-shaped metal high-voltage bushing 7 is tightly connected with the plug-in electric tree sample 1, and then put the integral connection device of the upper electrode 6 and the lower electrode 4 back to the middle position in the metal shell 13; S3: Check and determine whether the metal connection between the high voltage introduction port 5 and the high voltage power supply is intact, and whether the grounding condition between the lower electrode 4 and the metal shell 13 is good; S4: Connect the various components of the constant temperature wind heating device 9 through the air duct, and turn on the constant temperature wind heating device 9 until the wind speed and temperature in the entire experimental chamber tend to be stable; S5: When the temperature in the entire experimental chamber rises to a preset temperature, the high-voltage power supply is started, and the growth of the electrical tree branches is experimentally recorded by the electrical tree branch detection device 10; after the recording is completed, the operation of the high-voltage power supply and the constant temperature wind heating device 9 are stopped in sequence; S6: Repeat steps S2-S5 to test different plug-in electrical tree specimens 1 until all preset experimental procedures are completed; S7: After the experimental procedures are all completed, disconnect the metal connecting wire from the high-voltage power supply, and when the circulating air in the constant temperature wind heating device 9 drops to room temperature, clean the various components of the electric tree experiment device for constant temperature wind heating of solid media, and end the experiment.

[0036] Specifically, the voltage value and the preset temperature provided by the high voltage power supply are selected according to the insulation characteristics of the sample to be tested.

[0037] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. An electric tree experiment device for constant temperature wind heating of solid medium, characterized in that: The invention comprises a plug-in electrical tree specimen (1), a metal electrode base (3), a lower electrode (4), a high-voltage introduction port (5), an upper electrode (6), a needle-shaped metal high-voltage bushing (7), an insulating support column (8), a constant temperature wind heating device (9), an electrical tree detection device (10) and a metal shell (13); the left and right sides between the upper electrode (6) and the lower electrode (4) are connected to each other through the insulating support column (8) to form an experimental chamber; the high-voltage introduction port (5) is connected to the upper electrode (6); the plug-in electrical tree specimen (1) is installed on the top of the lower electrode (4) through the metal electrode base (3); one end of the needle-shaped metal high-voltage bushing (7) is connected to the upper electrode (6) and the other end is detachably connected to the plug-in electrical tree specimen (1); the electrical tree detection device (10) is installed at the bottom of the upper electrode (6) and directly faces the plug-in electrical tree specimen (1); the constant temperature wind heating device (9) is installed in the experimental chamber; The lower electrode (4) is connected to the inner bottom of a metal shell (13); the metal shell (13) is provided with a metal window (11) facing the experimental cavity; the metal window (11) is covered with an insulating and heat-insulating front plate (12).

2. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The device also includes a sample fixing rolling belt (2), the bottom of the metal electrode base (3) is provided with a mounting groove, and the sample fixing rolling belt (2) passes through the outer side of the pin-insertion electrical tree sample (1) and the mounting groove of the metal electrode base (3) to fix the pin-insertion electrical tree sample (1) and the metal electrode base (3).

3. The electric tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The needle-shaped metal high-voltage bushing (7) is made of tungsten steel and has a needle-shaped discharge tip.

4. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The insulating and heat-insulating front plate (12) is made of polytetrafluoroethylene.

5. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The electrical tree branch detection device (10) detects the inside of the experimental chamber through ultrasonic waves, and automatically collects the electrical tree branch morphology when changes in the electrical tree branches are detected.

6. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: There are a plurality of constant temperature wind heating devices (9), which are respectively installed on the insulating support columns (8) on both sides of the experimental chamber.

7. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The constant temperature wind heating device (9) comprises a fan and a heating wire whose temperature can be controlled, and the fan is used to blow the stable hot air generated by the heating wire toward the pin-inserted electrical tree branch sample (1).

8. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1 is characterized in that: The device further comprises a base, which is arranged below the lower electrode (4) and is used to balance the lower electrode (4) inside the metal shell (13).

9. The electric tree tree experiment device for constant temperature wind heating of solid medium according to claim 1, characterized in that: The insulating and heat-insulating front plate (12) is welded to the metal housing (13) in conjunction with the metal window (11).

10. An experimental method based on an electric tree experiment device for constant temperature wind heating of solid medium as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1: cleaning the surfaces of the various components of the electric tree experiment device and checking whether the lower electrode (4) is well grounded; S2: taking out the integral connection device of the upper electrode (6) and the lower electrode (4) in the metal shell (13) from the electrical tree test device, placing the plug-in electrical tree specimen (1) to be tested on the metal electrode base (3), fixing the plug-in electrical tree specimen (1) and the metal electrode base (3) with a specimen fixing rolling belt (2), putting a needle-shaped metal high-voltage bushing (7) on the needle electrode of the plug-in electrical tree specimen (1), and then putting the integral connection device of the upper electrode (6) and the lower electrode (4) back into the metal shell (13); S3: Check and determine whether the metal connection between the high voltage introduction port (5) and the high voltage power supply is intact, and whether the grounding condition between the lower electrode (4) and the metal housing (13) is good; S4: connecting the various components of the constant temperature wind heating device (9) through the air duct, and turning on the constant temperature wind heating device (9) until the wind speed and temperature in the entire experimental chamber tend to be stable; S5: When the temperature in the entire experimental chamber rises to a preset temperature, the high-voltage power supply is started, and the growth of the electrical tree branches is experimentally recorded through the electrical tree branch detection device (10); after the recording is completed, the operation of the high-voltage power supply and the constant temperature wind heating device (9) are stopped in sequence; S6: repeating steps S2-S5 to test different plug-in electrical tree specimens (1) until all preset experimental procedures are completed; S7: After the experimental procedures are all completed, disconnect the metal connecting wire from the high-voltage power supply, and when the circulating air in the constant temperature wind heating device (9) drops to room temperature, clean the various components of the electrical tree experiment device for constant temperature wind heating of solid media, and end the experiment.

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