Testing device and method for simulating ablation of sleeve threaded connection structure of oil-filled equipment

Abstract

The invention provides a test device and method for simulating ablation of a sleeve threaded connection structure of oil-filled equipment. The device comprises an oil tank with a top opening, an insulating supporting plate, a vibration device, a connecting column, a current-carrying tube and a base, the insulating support plate is arranged at the top of the oil tank; the first end of the connecting column is arranged above the insulating supporting plate and connected with a voltage source, the connecting column penetrates through and is connected to the insulating supporting plate, and the second end of the connecting column is arranged in the oil tank; the first end of the current-carrying tube is connected with the second end of the connecting column, the second end of the current-carrying tube is in threaded connection with the base, and the base is connected with the part, arranged in the oil tank, of the reactor through a lead; the vibration device is arranged on the insulating support plate. According to the invention, the electric ablation state of the connecting part of the current-carrying tube and the base can be obtained, and the influence of current electrification on the metal structure at the connecting part is analyzed, so that the equipment fault caused by electric ablation is predicted and prevented, the stable operation of a power system is ensured, and the danger is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power systems, and in particular to a test device and method for simulating the ablation of a casing threaded connection structure of an oil-filled device. Background Art

[0002] As a common problem in large oil-filled equipment bushings in power systems, electro-erosion has long been a focus of electrical engineering research. As the capacity and operating voltage of power systems increase, the threat of electro-erosion to system stability is also increasing. Therefore, developing threaded connection technology that can withstand high current and high voltage conditions while reducing the occurrence of electro-erosion has become an important research direction.

[0003] In order to analyze the effect of long-term current on the metal structure of the threaded connection, an electric erosion experiment is required. However, conducting an electric erosion experiment in an actual high-resistance fault is dangerous and costly, which is not conducive to the experiment. Summary of the invention

[0004] In view of this, the present invention proposes a test device for simulating the ablation of the threaded connection structure of the casing of oil-filled equipment, aiming to solve the problem of high risk and high cost of conducting electric ablation experiments in high-resistance faults in the prior art. The present invention also proposes a method for conducting an experiment using the test device for simulating the ablation of the threaded connection structure of the casing of oil-filled equipment.

[0005] In one aspect, the present invention proposes a test device for simulating the ablation of the threaded connection structure of the casing of an oil-filled equipment, the device comprising: an oil tank with an open top, an insulating support plate, a vibration device, and a connecting column, a current-carrying tube and a base all of which are made of conductive materials; wherein the insulating support plate is arranged on the top of the oil tank; the first end of the connecting column is placed above the insulating support plate and is used to connect to a voltage source, the connecting column is passed through and connected to the insulating support plate, and the second end of the connecting column is placed in the oil tank; the first end of the current-carrying tube is connected to the second end of the connecting column, the second end of the current-carrying tube is connected to the base by a thread, and the base is used to connect to the part of the reactor placed in the oil tank by a lead; the vibration device is arranged on the insulating support plate.

[0006] Furthermore, the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment also includes: a force-applying mechanism; wherein the force-applying mechanism is arranged between the current-carrying tube and the base, and is used to apply force to the connection between the current-carrying tube and the base.

[0007] Furthermore, in the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment, the force-applying mechanism includes: a ring-shaped bracket body and at least two support columns; wherein the outer diameter of the second end of the connecting column is larger than the outer diameter of the current-carrying tube; the bracket body is sleeved on the outside of the current-carrying tube and abuts against the end of the second end of the connecting column; and each support column is arranged between the bracket body and the base at intervals along the circumferential direction.

[0008] Furthermore, in the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment, the end face of the second end of the connecting column is provided with a threaded hole extending toward the first end, the first end of the current-carrying tube is inserted and screwed into the threaded hole, and the second end of the connecting column and the first end of the current-carrying tube form a step-like structure to abut the bracket body.

[0009] Furthermore, the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment also includes: an insulating pad; wherein the insulating pad is arranged in the oil tank, and the insulating pad is placed below the base and has a preset distance between the insulating pad and the base.

[0010] Furthermore, in the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment, mounting plates are provided on the tops of the two opposite side walls of the oil tank extending outward; the insulating support plate is connected to the two mounting plates by bolts.

[0011] Furthermore, in the above-mentioned test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment, a support body is provided on each mounting plate; and the support body is in contact with the insulating support plate.

[0012] In the present invention, an insulating support plate is horizontally arranged on the top of the oil tank and a vibration device is arranged on it. The vibration device makes the oil tank vibrate, which can simulate the actual application environment. The connecting column is arranged on the insulating support plate and connected to the base through a current-carrying tube, so that the current-carrying tube and the base are stably placed in the oil tank. The current-carrying tube and the base are threadedly connected. The voltage source applies voltage to the connecting column, so that the connecting part of the current-carrying tube and the base is discharged, thereby obtaining the electrical ablation state of the connecting part of the current-carrying tube and the base, and then the influence of current on the metal structure at the connecting part of the current-carrying tube and the base can be analyzed, so that equipment failure caused by electrical ablation can be predicted and prevented, and the stable operation of the power system can be ensured. The test device is a simulation device, which can verify and simulate the electrical ablation characteristics at the connecting part of the current-carrying tube and the base under actual use conditions. There is no need to perform electrical ablation experiments in actual high-resistance faults, which reduces the danger and saves costs, and solves the problem of high danger and high cost of performing electrical ablation experiments in high-resistance faults in the prior art.

[0013] On the other hand, the present invention also proposes a method for testing using any of the above-mentioned test devices for simulating the ablation of the threaded connection structure of the casing of an oil-filled equipment, the method comprising the following steps: detecting the ablation condition of the connection part between the current-carrying tube and the base in a first connection state, and obtaining a first detection result; wherein the first connection state includes: the current-carrying tube is tightly connected to the base and is in a vibration environment, and a preset voltage is applied to the current-carrying tube; detecting the ablation condition of the connection part between the current-carrying tube and the base in a second connection state, and obtaining a second detection result; wherein the second connection state includes: the current-carrying tube is loosely connected to the base and is in a vibration environment, and a preset voltage is applied to the current-carrying tube; comparing the first detection result and the second detection result, and obtaining an analysis of the impact of current on the metal structure of the connection part between the current-carrying tube and the base.

[0014] Furthermore, in the above test method, when a preset ablation feature appears at a connection portion between the current-carrying tube and the base, the ablation condition of the connection portion between the current-carrying tube and the base is detected.

[0015] Furthermore, in the above test method, the loose connection between the current-carrying tube and the base is as follows: the nominal diameter of the thread of the second end of the current-carrying tube is smaller than the nominal diameter of the thread of the base.

[0016] In the present invention, two current-carrying tubes are taken respectively, one of which is normally and tightly connected to the base, and in a vibration environment, a voltage source is used to apply power to detect the ablation of the connection part between the current-carrying tube and the base, and a first detection result is obtained; the other current-carrying tube is loosely connected to the base, and in a vibration environment, a voltage source is used to apply power to detect the ablation of the connection part between the current-carrying tube and the base, and a second detection result is obtained. The first detection result and the second detection result are compared to obtain an analysis of the influence of current on the metal structure of the connection part between the current-carrying tube and the base. The test method can simulate the electric ablation phenomenon when the thread is normally tightened and loosely connected, and verify the electric ablation characteristics of the connection part between the current-carrying tube and the base caused by looseness or current operation under actual use conditions, and can accurately analyze the influence of current on the metal structure of the connection part between the current-carrying tube and the base, so as to predict and prevent equipment failures caused by electric ablation, and ensure the stable operation of the power system. The method does not need to perform electric ablation experiments in actual high-resistance faults, reduces the danger, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0018] Figure 1A schematic diagram of the structure of a test device for simulating the ablation of a threaded connection structure of a casing of an oil-filled device provided in an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of a top view of a test device for simulating ablation of a casing threaded connection structure of an oil-filled device provided in an embodiment of the present invention;

[0020] Figure 3 A flow chart of a test method for simulating ablation of a threaded connection structure of a casing of an oil-filled device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] Device Example:

[0023] See also Figure 1 to Figure 2 The figure shows the preferred structure of the test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment in this embodiment. As shown in the figure, the test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment includes: an oil tank 1, an insulating support plate 2, a vibration device 3, a connecting column 4, a current-carrying tube 5 and a base 6. Among them, the top of the oil tank 1 ( Figure 1 The upper part shown in the figure is open, and the oil tank 1 stores transformer oil.

[0024] The insulating support plate 2 is disposed on the top of the oil tank 1, and the insulating support plate 2 is detachably connected to the top of the oil tank 1. Preferably, the tops of the two opposite side walls of the oil tank 1 are both provided with mounting plates 13 extending outward, and the insulating support plate 2 is connected to the two mounting plates 13 by bolts. Specifically, there are two mounting plates 13, and the two mounting plates 13 are respectively disposed on the two opposite sides of the top of the oil tank 1, each mounting plate 13 is perpendicular to the side wall of the oil tank 1, and each mounting plate 13 extends in a direction away from the oil tank 1. The insulating support plate 2 is erected on the top of the oil tank 1, and the two ends of the insulating support plate 2 overlap the two mounting plates 13, and each end of the insulating support plate 2 is connected to the corresponding mounting plate 13 by bolts.

[0025] The first end of the connecting column 4 ( Figure 1The upper end shown in the figure) is placed above the insulating support plate 2, and the first end of the connecting column 4 is connected to the voltage source 7, the connecting column 4 is penetrated through the insulating support plate 2, and the second end of the connecting column 4 ( Figure 1 The lower end shown in the figure is placed in the oil tank 1. In addition, the connecting column 4 is connected to the insulating support plate 2 so that the connecting column 4 and the insulating support plate 2 are relatively fixed, and the connection can be a bolt connection. Specifically, the connecting column 4 is provided with a mounting portion 41, and the mounting portion 41 is placed on the insulating support plate 2 and in contact with the insulating support plate 2. The mounting portion 41 is provided with at least two bolt holes, and each bolt hole corresponds to a bolt. The insulating support plate 2 is provided with a threaded hole corresponding to each bolt hole, and each bolt is penetrated through the corresponding bolt hole and is screwed with the corresponding threaded hole, so that the mounting portion 41 is connected to the insulating support plate 2 by bolts, that is, the connecting column 4 is connected to the insulating support plate 2.

[0026] The current-carrying tube 5 and the base 6 are both placed in the oil tank 1. The first end of the current-carrying tube 5 ( Figure 1 The upper end shown in FIG. 1 is connected to the second end of the connecting column 4, and the second end of the current-carrying tube 5 ( Figure 1 The lower end of the connecting column 4 is connected to the base 6 by threads. Specifically, the first end of the current-carrying tube 5 is screwed to the second end of the connecting column 4. More specifically, a threaded hole extending toward the first end is provided on the end surface of the second end of the connecting column 4, and a thread is provided on the outer wall of the first end of the current-carrying tube 5. The first end of the current-carrying tube 5 is inserted into the threaded hole of the second end of the connecting column 4 and screwed to the threaded hole, so that the second end of the connecting column 4 and the first end of the current-carrying tube 5 form a step-like structure.

[0027] The base 6 is connected to the part of the reactor 9 placed in the oil tank 1 through the lead 8. Specifically, the reactor 9 is placed outside the oil tank 1, one end of the reactor 9 is grounded, and the other end is connected to the first end of the connecting sleeve 15 ( Figure 1 The connecting sleeve 15 is arranged on the side wall of the oil tank 1 and its second end ( Figure 1 The lead wire 8 is placed in the fuel tank 1, and the first end of the lead wire 8 ( Figure 1 The right end shown in FIG. 1 is connected to the base 6, and the second end of the lead 8 ( Figure 1 The left end shown in the figure is connected to the second end of the connecting sleeve 15.

[0028] The vibration device 3 is arranged on the insulating support plate 2. The vibration device 3 can be a vibration motor or other vibration devices, and this embodiment does not impose any restrictions on this. The vibration device 3 is used to vibrate the oil tank 1 as a whole, thereby vibrating the connection between the current-carrying tube 5 and the base 6.

[0029] Preferably, each mounting plate 13 is provided with a support body 14, and the insulating support plate 2 is covered on the two support bodies 14 and connected to the mounting plate 13 by bolts, so that the support body 14 is in contact with the insulating support plate 2. In this way, the insulating support plate 2 is not in direct contact with the mounting plate 13, but in contact with the support body 14, which reduces the contact area, thereby reducing the error caused by friction, and can also enhance the vibration generated by the vibration device 3. In specific implementation, the support body 14 can be a columnar body, such as an iron rod; or the support body 14 can include: a plurality of spheres, each sphere is arranged on the mounting plate 13 at intervals, and each sphere is in contact with the insulating support plate 2. This embodiment does not impose any restrictions on the specific structure of the support body 14.

[0030] The connecting column 4 , the current-carrying tube 5 and the base 6 are all made of conductive materials. Specifically, the connecting column 4 and the current-carrying tube 5 can be made of aluminum, and the base 6 can be a brass base.

[0031] In specific implementation, the connecting column 4 can be an aluminum connecting column. Aluminum is used because the cost of aluminum material is lower than that of copper, and it is light in weight, which reduces the burden and overall cost of the insulating support plate 2 and is not easily corroded.

[0032] The liquid level of the oil tank 1 at least submerges the connection portion between the current-carrying tube 5 and the base 6 , that is, the transformer oil in the oil tank 1 submerges the base 6 and the portion of the current-carrying tube 5 including the second end.

[0033] During the specific test, a current-carrying tube 5 is taken, the thread of which matches the thread of the base 6, and the current-carrying tube 5 is threadedly connected to the base 6, which is a normal tightening connection. The voltage source 7 is started, and the voltage source 7 applies voltage to the connecting column 4. Since the connecting column 4 is connected to the base 6 through the current-carrying tube 5, the base 6 is connected to the reactor 9 through the lead 8, and one end of the reactor 9 is grounded, a loop is formed between the connecting column 4, the current-carrying tube 5, the base 6 and the reactor 9, and the voltage source 7 applies voltage to the loop. At the same time, the reactor 9 acts as a reactor as the main load, and current is generated in the loop after the voltage is applied. The vibration device 3 is started and the test begins. The staff observes the ablation of the connection between the current-carrying tube 5 and the base 6. When severe ablation occurs, the test is stopped, the voltage source 7 and the vibration device 3 are turned off, and the ablation of the connection between the current-carrying tube 5 and the base 6 is observed and detected by using a special detection instrument, and the detection results are recorded. Specifically, the detection instrument is used to perform metallographic analysis and a scanning electron microscope to detect the metal organization and structure inside the thread, and the influence of ablation on the metal microstructure is analyzed.

[0034] Take a new current-carrying tube 5, the thread nominal diameter of the second end of the new current-carrying tube 5 is smaller than the thread nominal diameter of the base 6, and the second end of the current-carrying tube 5 is threadedly connected to the base 6, which is a loose connection. Start the voltage source 7 and the vibration device 3, and the staff observes the ablation of the connection between the current-carrying tube 5 and the base 6. When severe ablation occurs, stop the test, use a special detection instrument to observe and detect the ablation of the connection between the current-carrying tube 5 and the base 6, and record the detection results.

[0035] The detection results of the connection parts of the current-carrying tube 5 and the base 6 when the connection is normally tightened are compared and analyzed with the detection results of the connection parts of the current-carrying tube 5 and the base 6 when the connection is loose, and the influence of the current supply and the loose state on the metal structure at the connection part of the current-carrying tube 5 and the base 6 is analyzed.

[0036] During the specific test, no matter the current-carrying tube 5 and the base 6 are normally fastened or loosely connected, the vibration device 3 is in the start-up vibration state from the beginning of the test to the end of the test, so that the oil tank 1 is in a vibration state during the test, simulating the use of the real environment. In the vibration environment, the reactions of the connection parts in different thread states (loose connection and normal fastening connection) are significantly different (for example, under vibration conditions, the poor contact of the threaded connection part leads to changes in electrical contact impedance, which in turn aggravates the electrical ablation phenomenon and accelerates the test process). In this way, the risk assessment of electrical ablation can be more realistic and effective, and the impact of the electrical ablation on the metal structure at the connection part of the current-carrying tube 5 and the base 6 can be determined.

[0037] During the specific test, the voltage source 7 is removed regularly to observe the ablation condition of the connection part between the current-carrying tube 5 and the base 6.

[0038] During the specific test, the first end of the current-carrying tube 5 is threadedly connected to the second end of the connecting column 4. When the connection is normally tightened, the thread of the first end of the current-carrying tube 5 matches the thread in the threaded hole of the second end of the connecting column 4, and the thread of the second end of the current-carrying tube 5 matches the thread of the base 6. Then, both ends of the current-carrying tube 5 are in a normal screw-connected tightening state. In this embodiment, the threads of both ends of the current-carrying tube 5 are M95. When the connection is loose, the thread of the first end of the current-carrying tube 5 matches the thread in the threaded hole of the second end of the connecting column 4, and the thread nominal diameter of the second end of the current-carrying tube 5 is smaller than the thread nominal diameter of the base 6. Then, the first end of the current-carrying tube 5 is in a normal screw-connected tightening state, and the second end of the current-carrying tube 5 is in a loose connection state. In this embodiment, the thread of the first end of the current-carrying tube 5 is M95, and the thread of the second end is M93.

[0039] During the specific test, the voltage is provided to the test device by direct output of a 15000kVA generator, that is, the voltage source 7 provides a voltage of about 3.7kV. The reactor 9 can be a 10kV dry-type iron core reactor, which serves as an inductor (10Ω), so that the current flowing through the current-carrying tube 5 is approximately 378A. The voltage and current are continuously applied, and when severe ablation characteristics appear at the connection between the current-carrying tube 5 and the base 6, the test is terminated, and the ablation characteristic results are recorded.

[0040] The connection between the current-carrying tube 5 and the base 6 was subjected to high-amplitude vibration and a running current of 378A for 26 hours. Analysis showed that intermittent discharge occurred at the threaded connection and local discharge signals could be measured. After the test, it was found that the threads of the current-carrying tube 5 were severely damaged, mostly mechanically and a small partly due to discharge damage, with 103μL / L of acetylene (partly from other structures). Metallographic and scanning electron microscopic examinations of the threads after ablation showed that discharge ablation would affect the internal metal organization and structure of the threads, causing thread failure and aggravating the degree of ablation in this area.

[0041] The test device can simulate the loose state of the connection part between the current-carrying tube 5 and the base 6, apply and maintain a high voltage to the connection part, so that the connection part is continuously discharged, and after long-term discharge, the current-carrying tube 5 and the base 6 are disassembled to observe the ablation state of the surface of the current-carrying tube 5 and the base 6. The test device can verify the electrical ablation morphology and electrical ablation characteristics of the connection part of the threaded connection between the current-carrying tube 5 and the base 6 caused by looseness or current operation.

[0042] This embodiment can simulate the actual use environment and conditions, simulate the electrical erosion phenomenon under high voltage and high current conditions when the threads are loose and normally tightened, and further analyze the influence of long-term current on the metal structure at the threaded connection between the current-carrying tube 5 and the base 6, including the mechanical and chemical damage caused by partial discharge, so that it is easy to understand how the mechanical strength and durability of the threaded connection are affected by the electrical erosion phenomenon under extreme conditions, and how this influence leads to connection failure. The test device reproduces the thread discharge and gas production process, and the discharge will affect the internal metal organization and thread structure of the thread, affect the mechanical strength of the threaded connection and cause the thread failure, and thus can provide guidance and basis for the development, installation and fatigue damage analysis of the casing of large oil-filled equipment.

[0043] It can be seen that in this embodiment, the insulating support plate 2 is arranged on the top of the oil tank 1 and a vibration device is arranged thereon, the vibration device makes the oil tank 1 vibrate, which can simulate the actual application environment, the connecting column 4 is arranged on the insulating support plate 2 and connected to the base 6 through the current-carrying tube 5, so that the current-carrying tube 5 and the base 6 are stably placed in the oil tank 1, the current-carrying tube 5 and the base 6 are threadedly connected, and the voltage source 7 applies voltage to the connecting column 4, so that the connection part of the current-carrying tube 5 and the base 6 is discharged, thereby obtaining the electrical ablation state of the connection part of the current-carrying tube 5 and the base 6, and then the influence of the current on the metal structure at the connection part of the current-carrying tube 5 and the base 6 can be analyzed, so that the equipment failure caused by electrical ablation can be predicted and prevented, and the stable operation of the power system can be ensured. The test device is a simulation device, which can verify and simulate the electrical ablation characteristics at the connection part of the current-carrying tube 5 and the base 6 under actual use conditions, and there is no need to perform electrical ablation experiments in actual high-resistance faults, which reduces the danger and saves costs, and solves the problem of high danger and high cost of performing electrical ablation experiments in high-resistance faults in the prior art.

[0044] See also Figure 1 In the above embodiment, the test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment further includes: a force-applying mechanism. The force-applying mechanism is arranged between the current-carrying tube 5 and the base 6, and is used to apply force to the connection between the current-carrying tube 5 and the base 6, that is, to apply force to the threads between the current-carrying tube 5 and the base 6, thereby ensuring the test results.

[0045] The force-applying mechanism includes: a support body 10 and at least two support columns 11. The outer diameter of the second end of the connecting column 4 is greater than the outer diameter of the current-carrying tube 5. Specifically, a step-shaped structure is formed between the second end of the connecting column 4 and the first end of the current-carrying tube 5. More specifically, the outer diameter of the second end of the connecting column 4 is greater than the outer diameter of the first end, and the diameter of the threaded hole opened at the end of the second end of the connecting column 4 matches the outer diameter of the first end of the current-carrying tube 5.

[0046] The bracket body 10 is annular, and is sleeved on the outside of the current-carrying tube 5, and the bracket body 10 abuts against the end of the second end of the connecting column 4. Specifically, the inner diameter of the bracket body 10 matches the outer diameter of the current-carrying tube 5, and since a step-like structure is formed between the second end of the connecting column 4 and the first end of the current-carrying tube 5, the top of the bracket body 10 abuts against the end of the second end of the connecting column 4, that is, the top of the bracket body 10 abuts against the step-like structure.

[0047] Each support column 11 is disposed between the support body 10 and the base 6. Specifically, the transverse cross-sectional dimension of the base 6 is greater than the outer diameter of the current-carrying tube 5, and the transverse cross-sectional dimension of the base 6 is greater than or equal to the outer diameter of the support body 10. The first end of each support column 11 is screwed to the support body 10, and the second end of each support column 11 is abutted against the base 6. Each support column 11 is disposed outside the current-carrying tube 5 at intervals along the circumferential direction of the current-carrying tube 5, and each support column 11 supports the support body 10.

[0048] It can be seen that in this embodiment, each support column 11 is screwed with the bracket body 10, so that each support column 11 is connected to the bracket body 10, the bracket body 10 abuts against the end of the second end of the connecting column 4, and the second end of each support column 11 abuts against the base 6, so that a force can be applied to the thread between the current-carrying tube 5 and the base 6, thereby improving the accuracy of the test results.

[0049] See also Figure 1 In the above embodiments, the test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment also includes: an insulating pad 12. The insulating pad 12 is arranged in the oil tank 1. Specifically, the two ends of the insulating pad 12 are connected to the two opposite side walls of the oil tank 1 in a one-to-one correspondence, and the insulating pad 12 is placed in the transformer oil in the oil tank 1. The insulating pad 12 is placed below the base 6, and there is a preset distance between the insulating pad 12 and the base 6. The preset distance can be determined according to actual conditions, and this embodiment does not impose any restrictions on this. In this embodiment, the distance between the insulating pad 12 and the base 6 is 10 mm. In this way, when the current-carrying tube 5 is loosened from the base 6, the insulating pad 12 supports the base 6 to prevent the base 6 from falling to the bottom of the oil tank 1.

[0050] In summary, in this embodiment, the voltage source 7 applies voltage to the connecting column 4, so that the connecting part of the current-carrying tube 5 and the base 6 is discharged, thereby obtaining the electrical ablation state of the connecting part of the current-carrying tube 5 and the base 6, and then being able to analyze the influence of the current on the metal structure at the connecting part of the current-carrying tube 5 and the base 6, so as to predict and prevent equipment failures caused by electrical ablation, and ensure the stable operation of the power system. The test device is a simulation device, which can verify and simulate the electrical ablation characteristics at the connecting part of the current-carrying tube 5 and the base 6 under actual use conditions, and there is no need to perform electrical ablation experiments in actual high-resistance faults, which reduces the danger and saves costs.

[0051] Method Example:

[0052] This embodiment also proposes a method for conducting a test using any of the above-mentioned test devices for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment. The specific implementation process of the test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment can be found in the above description, and this embodiment will not be repeated here. Figure 3 , the test method comprises the following steps:

[0053] Step S1, detecting the ablation condition of the connection part between the current-carrying tube and the base in the first connection state, and obtaining a first detection result; wherein the first connection state includes: the current-carrying tube is tightly connected to the base and is in a vibration environment, and a preset voltage is applied to the current-carrying tube.

[0054] Specifically, see Figure 1 , take a current-carrying tube, the thread of the second end of the current-carrying tube 5 matches the thread of the base 6, and the current-carrying tube 5 is threadedly connected to the base 6, which is a normal tightening connection.

[0055] In specific implementation, the first end of the current-carrying tube 5 is threadedly connected to the second end of the connecting column 4. When normally tightened, the thread of the first end of the current-carrying tube 5 matches the thread in the threaded hole of the second end of the connecting column 4, and the thread of the second end of the current-carrying tube 5 matches the thread of the base 6, so that both ends of the current-carrying tube 5 are in a normal threaded tightening state.

[0056] In this embodiment, when the connection is normally tightened, the threads of both ends of the current-carrying tube are M95.

[0057] During the test, a preset voltage is applied to the connecting column through a voltage source, and the vibration device is started at the same time. Figure 1 The reactor 9 is placed outside the oil tank 1, one end of the reactor 9 is grounded, and the other end is connected to the first end of the connecting sleeve 15, the connecting sleeve 15 is passed through the side wall of the oil tank 1 and the second end thereof is placed inside the oil tank 1. The bottom of the base 6 is connected to the second end of the connecting sleeve 15 through the lead 8.

[0058] The voltage source 7 applies a preset voltage to the first end of the connecting column 4. Since the connecting column 4 is connected to the base 6 through the current-carrying tube 5, the base 6 is connected to the reactor 9 through the lead 8 and the connecting sleeve 15, and one end of the reactor 9 is grounded, a loop is formed between the connecting column 4, the current-carrying tube 5, the base 6, the connecting sleeve 15 and the reactor 9, and the voltage source 7 applies voltage to the loop. At the same time, the reactor 9 acts as a reactor as the main load, and current is generated in the loop after the voltage is applied.

[0059] During specific implementation, the preset voltage may be determined according to actual conditions, and this embodiment does not impose any limitation on this.

[0060] From the beginning to the end of the test, the vibration device is in a vibrating state, so that the oil tank is in a vibrating state during the test, simulating the situation in the real environment. In actual applications, the connection structure between the current-carrying tube and the base will be exposed to various vibration sources. During the test, the vibration device makes the oil tank in a vibrating state, which can more realistically simulate the actual application environment, thereby improving the accuracy of the test results.

[0061] When the connection part between the current-carrying tube and the base shows a preset ablation feature, the test is stopped, and the ablation condition of the connection part between the current-carrying tube and the base is detected. Specifically, the staff observes whether the connection part between the current-carrying tube and the base shows ablation, and when the connection part between the current-carrying tube and the base shows a preset ablation feature, the test is stopped. The preset ablation feature can be determined according to actual conditions, and this embodiment does not impose any restrictions on this. In this embodiment, when the connection part between the current-carrying tube and the base shows severe ablation, the test is stopped. Then, a dedicated detection instrument is used to observe and detect the ablation condition of the connection part between the current-carrying tube and the base.

[0062] Step S2, detecting the ablation condition of the connection part between the current-carrying tube and the base in the second connection state, and obtaining a second detection result; wherein the second connection state includes: the current-carrying tube and the base are loosely connected and in a vibration environment, and a preset voltage is applied to the current-carrying tube;

[0063] Specifically, a new current-carrying tube is taken and the new current-carrying tube is loosely connected to the base. The thread nominal diameter of the second end of the new current-carrying tube is smaller than the thread nominal diameter of the base, and the second end of the current-carrying tube is threadedly connected to the base, which is a loose connection.

[0064] For specific implementation, see Figure 1 When the connection is loosened, the thread of the first end of the current-carrying tube 5 matches the thread in the threaded hole of the second end of the connecting column 4, and the nominal diameter of the thread of the second end of the current-carrying tube 5 is smaller than the nominal diameter of the thread of the base 6. Then, the first end of the current-carrying tube 5 is in a normal threaded state, and the second end of the current-carrying tube 5 is in a loosely connected state.

[0065] In this embodiment, when the connection is loosened, the thread of the first end of the current-carrying tube is M95, and the thread of the second end is M93.

[0066] During the test, a preset voltage is applied to the connection column through a voltage source, and the vibration device is started at the same time. From the beginning of the test to the end of the test, the vibration device is in a vibrating state, so that the oil tank is in a vibrating state during the test, simulating the situation in the real environment.

[0067] When the connection part between the current-carrying tube and the base shows a preset ablation feature, the test is stopped, and the ablation condition of the connection part between the current-carrying tube and the base is detected. Specifically, the staff observes whether the connection part between the current-carrying tube and the base shows ablation, and when the connection part between the current-carrying tube and the base shows a preset ablation feature, the test is stopped. In this embodiment, when the connection part between the current-carrying tube and the base shows severe ablation, the test is stopped. Then, a dedicated detection instrument is used to observe and detect the ablation condition of the connection part between the current-carrying tube and the base.

[0068] Step S3, comparing the first detection result and the second detection result to obtain an analysis of the effect of current on the metal structure of the connection between the current-carrying tube and the base.

[0069] Specifically, a first detection result when the current-carrying tube and the base are normally tightly connected is compared and analyzed with a second detection result when the current-carrying tube and the base are loosely connected, so as to obtain an analysis of the influence of current on the metal structure of the connection part between the current-carrying tube and the base.

[0070] It can be seen that in this embodiment, two current-carrying tubes are taken respectively, one of which is normally tightly connected to the base, and power is applied by a voltage source in a vibration environment to detect the ablation of the connection part between the current-carrying tube and the base and obtain a first detection result, and the other current-carrying tube is loosely connected to the base, and power is applied by a voltage source in a vibration environment to detect the ablation of the connection part between the current-carrying tube and the base and obtain a second detection result, and the first detection result and the second detection result are compared to obtain an analysis of the influence of current on the metal structure of the connection part between the current-carrying tube and the base. This test method can simulate the electric ablation phenomenon when the thread is normally tightened and loosely connected, and verify the electric ablation characteristics of the connection part between the current-carrying tube and the base caused by looseness or current operation under actual use conditions, and can accurately analyze the influence of current on the metal structure of the connection part between the current-carrying tube and the base, so as to predict and prevent equipment failures caused by electric ablation, and ensure the stable operation of the power system. This method does not need to perform electric ablation experiments in actual high-resistance faults, reduces the danger, and saves costs.

[0071] It should be noted that the principles of the test device and test method for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment in the present invention are the same, and the relevant parts can be referenced to each other.

[0072] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0073] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A test device for simulating the ablation of the threaded connection structure of the casing of an oil-filled equipment, characterized in that: include: An oil tank (1) with an open top, an insulating support plate (2), a vibrating device (3), a connecting column (4), a current-carrying tube (5) and a base (6) all made of conductive materials; wherein: The insulating support plate (2) is arranged on the top of the oil tank (1); The first end of the connecting column (4) is placed above the insulating support plate (2) and is used to be connected to a voltage source (7); the connecting column (4) passes through and is connected to the insulating support plate (2); and the second end of the connecting column (4) is placed in the oil tank (1); The first end of the current-carrying tube (5) is connected to the second end of the connecting column (4), the second end of the current-carrying tube (5) is connected to the base (6) via a thread, and the base (6) is used to connect to the part of the reactor (9) placed in the oil tank (1) via a lead wire (8); The vibration device (3) is arranged on the insulating support plate (2).

2. The test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment according to claim 1 is characterized in that: Also includes: A force-applying mechanism; wherein: The force-applying mechanism is arranged between the current-carrying tube (5) and the base (6), and is used to apply a force to the connection between the current-carrying tube (5) and the base (6).

3. The test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment according to claim 2 is characterized in that: The force-applying mechanism comprises: a ring-shaped support body (10) and at least two support columns (11); wherein: The outer diameter of the second end of the connecting column (4) is greater than the outer diameter of the current-carrying tube (5); The bracket body (10) is sleeved on the outside of the current-carrying tube (5) and abuts against the end of the second end of the connecting column (4); The support columns (11) are arranged between the support body (10) and the base (6) at intervals along the circumferential direction.

4. The test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment according to claim 3 is characterized in that: The end surface of the second end of the connecting column (4) is provided with a threaded hole extending toward the first end, the first end of the current-carrying tube (5) is inserted into and screwed into the threaded hole, and the second end of the connecting column (4) and the first end of the current-carrying tube (5) form a step-like structure to abut against the bracket body (10).

5. The test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment according to claim 1 is characterized in that: Also includes: Insulating pad (12); wherein, The insulating pad (12) is arranged in the oil tank (1); the insulating pad (12) is placed below the base (6) and has a preset distance from the base (6).

6. The test device for simulating the ablation of the threaded connection structure of the casing of oil-filled equipment according to claim 1, characterized in that: The tops of two opposite side walls of the oil tank (1) are both provided with mounting plates (13) extending outwards; The insulating support plate (2) is connected to the two mounting plates (13) via bolts.

7. The test device for simulating the ablation of the threaded connection structure of the casing of the oil-filled equipment according to claim 6 is characterized in that: A support body (14) is provided on each of the mounting plates (13); The support body (14) is in contact with the insulating support plate (2).

8. A method for conducting a test using the test device for simulating the ablation of the threaded connection structure of the casing of an oil-filled equipment according to any one of claims 1 to 7, characterized in that: The steps include: Detecting the ablation condition of the connection part between the current-carrying tube and the base in the first connection state, and obtaining a first detection result; wherein the first connection state includes: the current-carrying tube and the base are tightly connected and in a vibration environment, and a preset voltage is applied to the current-carrying tube; Detecting the ablation condition of the connection part between the current-carrying tube and the base in the second connection state to obtain a second detection result; wherein the second connection state includes: the current-carrying tube is loosely connected to the base and is in a vibration environment, and a preset voltage is applied to the current-carrying tube; The first detection result and the second detection result are compared to obtain an analysis of the effect of current on the metal structure of the connection between the current-carrying tube and the base.

9. The test method according to claim 8, characterized in that When a preset ablation feature appears at a connection portion between the current-carrying tube and the base, the ablation condition of the connection portion between the current-carrying tube and the base is detected.

10. The test method according to claim 8, characterized in that: The loose connection between the current-carrying tube and the base is as follows: the nominal diameter of the thread of the second end of the current-carrying tube is smaller than the nominal diameter of the thread of the base.

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