A transformer oil arc discharge observation and gas collection device

Abstract

The present disclosure discloses a transformer oil arc discharge observation and gas collection device, comprising: a discharge tank body, a high-voltage measuring lead bushing and a low-voltage measuring lead bushing are arranged on one side of the discharge tank body, a high-voltage measuring lead is arranged in the high-voltage measuring lead bushing, and a low-voltage measuring lead is arranged in the low-voltage measuring lead bushing; a high-voltage incoming line bushing is arranged at the top of the discharge tank body, and a low-voltage outgoing line bushing is arranged at the bottom; a discharge electrode is arranged in the discharge tank body, which includes a high-voltage electrode and a low-voltage electrode; a gas outlet is also arranged on the discharge tank body, and the gas outlet is connected to a gas collection device for collecting gas generated by discharge of the discharge tank body.

Description

Technical Field

[0001] The present invention belongs to the field of insulating medium discharge characteristic test research, and in particular relates to a transformer oil arc discharge observation and gas collection device. Background Art

[0002] Large oil-filled power equipment is an important part of high-voltage electrical equipment. When high-energy arc discharge occurs inside it, it is usually accompanied by the deterioration of transformer oil and decomposition gas, which increases the pressure in the confined space, and then causes a deflagration in the transformer tank or bushing riser area, posing a great threat to the safe and stable operation of power equipment. Therefore, the arc discharge characteristics in transformer oil deserve in-depth study. At present, the deflagration test of transformer oil mostly adopts the method of real-type verification test, which conducts high-energy discharge in the real-type transformer tank or bushing riser, and measures the physical quantities such as pressure change, deformation and acceleration of the tank or riser. Although this method can intuitively verify the mechanical strength performance of the riser, it has the following disadvantages: 1. The test requires the use of a real oil tank or riser to perform MJ-level energy discharge. The test is large-scale and costly. Most of them are verification tests with a limited number of tests, which leads to insufficient effective data and makes it impossible to conduct in-depth exploration of the mechanism and discharge law of the arc in the oil; 2. In previous real-type tests, for the measurement of arc voltage, since the measurement point cannot be close to the arc root, the stray inductance in the circuit causes a large error in the measurement of the arc voltage in the oil. Therefore, the accuracy of the arc voltage data measured in the test is questionable, which in turn affects the calculation of the arc energy; 3. Usually, for the sake of structural mechanical strength, such real-type tests generally do not have an observation window, and the process of oil gasification decomposition caused by the arc and the increase in pressure in the oil tank caused by the movement of bubbles cannot be observed; 4. Such tests generally use gas collecting cylinders to collect the gas generated in the test, and use sensors to measure the pressure and temperature in the gas collecting cylinders. Due to temperature unevenness and sensor accuracy problems, measurement errors will occur.

[0003] Therefore, it is necessary to propose an oil arc discharge test platform and a gas collection device that are easy to carry out, cost-controlled, simple to operate, and can achieve accurate measurement and clear observation. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a transformer oil arc discharge observation and gas collection device, through which the generated gas can be more intuitively and effectively collected and the volume measured.

[0005] To achieve the above objectives, the present disclosure provides the following technical solutions:

[0006] A transformer oil arc discharge observation and gas collection device, comprising:

[0007] Discharge tank,

[0008] A high-voltage measuring lead sleeve and a low-voltage measuring lead sleeve are provided on one side of the discharge tank body, a high-voltage measuring lead is provided in the high-voltage measuring lead sleeve, and a low-voltage measuring lead is provided in the low-voltage measuring lead sleeve;

[0009] A high-voltage inlet bushing is provided at the top of the discharge tank, and a low-voltage outlet bushing is provided at the bottom;

[0010] The discharge tank is provided with a discharge electrode, which includes a high-voltage electrode and a low-voltage electrode;

[0011] The discharge tank body is also provided with a gas outlet, and the gas outlet is connected to a gas collecting device for collecting gas generated by discharge of the discharge tank body.

[0012] Preferably, a first arc-striking wire guide groove is provided at the axial center of the high-voltage electrode.

[0013] Preferably, a second arc-striking wire guide groove is provided at the axial center of the low-voltage electrode.

[0014] Preferably, a high-voltage incoming line is arranged in the high-voltage incoming line bushing, and the high-voltage electrode is connected to the high-voltage incoming line.

[0015] Preferably, a low-voltage outlet line is arranged in the low-voltage outlet line bushing, and the low-voltage electrode is connected to the low-voltage outlet line.

[0016] Preferably, the distance between the high voltage electrode and the low voltage electrode is 20 mm-80 mm.

[0017] Preferably, the high-voltage measurement lead is connected to the high-voltage electrode through a high-voltage measurement lead sleeve.

[0018] Preferably, the low-voltage measurement lead is connected to the low-voltage electrode through a low-voltage measurement lead sleeve.

[0019] Preferably, an observation window is also provided on the side of the discharge tank body adjacent to the pressure sensor mounting flange.

[0020] Preferably, the gas collecting device comprises a needle valve, a buffer gas bottle, a micro gas pump and a drainage gas collecting tank which are connected in sequence.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] According to the arc discharge observation and gas collection device in oil provided by the present disclosure, the purpose of convenient test operation and observation can be achieved, and the generated gas can be collected and the volume measured intuitively and effectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a structural schematic diagram of a transformer oil arc discharge observation and gas collection device provided by an embodiment of the present disclosure;

[0024] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle discharge tank;

[0025] Figure 3 yes Figure 2 Schematic diagram of the metal wire clamping electrode;

[0026] Figure 4 It is a circuit diagram of the arc triggered in oil by the microcavity jet plasma method;

[0027] The symbols in the accompanying drawings are explained as follows:

[0028] 1. Needle valve; 2. Buffer gas bottle; 3. Micro air pump; 4. Drainage gas collecting tank; 5. Discharge tank; 6. High-voltage incoming line; 7. Low-voltage outgoing line; 8. High-voltage incoming line bushing; 9. Low-voltage outgoing line bushing; 10. Observation window; 11. High-voltage measuring lead bushing; 12. High-voltage measuring lead; 13. Low-voltage measuring lead bushing; 14. Low-voltage measuring lead; 15-1. High-voltage electrode (15-1-1. Installation thread; 15-1-2. Arc-starting wire tightening screw hole; 15-1-3. First arc-starting wire guide groove; 15-1-4. Fastening ring); 15-2 Low-voltage electrode; 16. Pressure sensor mounting flange; 17. High-voltage needle electrode; 18. Ground electrode; 19. Polytetrafluoroethylene bushing; 20. Trigger needle electrode. DETAILED DESCRIPTION

[0029] The following will refer to the attached Figures 1 to 4 Specific embodiments of the present disclosure are described in detail. Although specific 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 described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0030] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be determined by the attached claims.

[0031] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present disclosure.

[0032] In one embodiment, if Figure 1 , Figure 2 As shown, a transformer oil arc discharge observation and gas collection device comprises:

[0033] Discharge tank 5,

[0034] A high-voltage measuring lead sleeve 11 and a low-voltage measuring lead sleeve 13 are provided on one side of the discharge tank body 5. A high-voltage measuring lead 12 is provided in the high-voltage measuring lead sleeve 11, and a low-voltage measuring lead 14 is provided in the low-voltage measuring lead sleeve 13.

[0035] A high-voltage inlet bushing 8 is provided at the top of the discharge tank body 5, and a low-voltage outlet bushing 9 is provided at the bottom;

[0036] The discharge tank 5 is provided with discharge electrodes, which include a high-voltage electrode 15-1 and a low-voltage electrode 15-2;

[0037] The discharge tank body 5 is also provided with a gas outlet, and the gas outlet is connected to a gas collecting device for collecting gas generated by discharge of the discharge tank body 5 .

[0038] In this embodiment, there are two ways to initiate the arc: (1) Use a metal wire to short-circuit the high-voltage electrode and the low-voltage electrode. When the high-voltage switch outside the discharge tank in the loop is turned on, a large current passes through the metal wire, which heats up and melts, forming a small conductive bridge composed of metal vapor and plasma in the oil, turning on the electrodes, and causing arc discharge in the oil; (2) Introduce a trigger pulse and use a microcavity to spray plasma to initiate the arc. The details are as follows: Figure 4As shown, the high-voltage electrode is set as a high-voltage needle electrode 17. The high-voltage needle electrode 17 is made of copper-tungsten alloy and is used to distort the electric field, which is easy to develop continuously. The ground electrode 18 is set as a structure with a small hole in the center. The needle tip of the high-voltage needle electrode 17 is facing the small hole of the ground electrode 18. The distance from the high-voltage needle electrode 17 to the small hole of the ground electrode 18 is 5mm, and the diameter of the small hole of the ground electrode 18 is 2mm. The trigger needle electrode 20 is facing the small hole on the ground electrode 18 through the polytetrafluoroethylene sleeve 19. The distance from the trigger needle electrode 20 to the ground electrode 18 is 2mm. When an instantaneous overvoltage is loaded on the trigger needle electrode 20, the small gap between the trigger needle electrode 20 and the ground electrode 18 is broken down, and surface discharge occurs on the surface of the polytetrafluoroethylene sleeve 19. Plasma is ejected from the small hole in the center of the ground electrode 18. The plasma penetrates the ground electrode 18 and the high-voltage needle electrode 17, distorting the electric field between the ground electrode 18 and the needle electrode 17, causing the main gap to break down. The method of using arc-starting wire is more stable and reliable; the method of using microcavity injection eliminates the step of replacing the wire, making the test operation more convenient.

[0039] In addition, since it is necessary to collect the gas generated by the discharge tank 5, a gas collection device is further provided on one side of the discharge tank in this embodiment so that the gas generated by the discharge can be collected and processed. It should be noted that the following contents were considered when designing the discharge tank and selecting the gas collection method: First, according to the preliminary test data and the results of relevant literature, it was determined that the energy of the arc discharge in oil suitable for laboratory conditions was in the hundreds of kJ level, and the maximum possible pressure value was calculated based on the discharge power, which was about 1.5 MPa, and the gas volume was about 10L. Based on this data, the wall thickness of the discharge tank was designed to be 10 mm, the material was Q235-B carbon steel, and the flange wall thickness was 50 mm.

[0040] This embodiment is different from a real-type test. Instead, it adopts a small-model, low-energy discharge test, thereby ensuring the safety of the test, controlling the test cost, ensuring that the test can be repeated many times, and changing the test conditions for multiple tests, ensuring sufficient test data.

[0041] In another embodiment, if Figure 3 As shown, a first arc-striking wire guide groove 15-1-3 is provided at the axial center of the high-voltage electrode.

[0042] In this embodiment, the top of the high-voltage electrode is provided with a mounting thread 15-1-1, and the high-voltage electrode is fixedly connected to the high-voltage incoming line 6 through the thread. When the arc-starting wire is used to start the arc, the arc-starting wire is wound around the bolt and screwed into the arc-starting wire tightening screw hole 15-1-2, so that the arc-starting wire can achieve the tightening effect. A first arc-starting wire guide groove 15-1-3 is provided in the high-voltage electrode, so that the arc-starting wire is fixed in the high-voltage electrode 15-1, thereby ensuring that the position of the arc-starting wire is fixed during each test. A fastening ring 15-1-4 is installed on the outside of the high-voltage electrode 15-1, which can be used to ensure that the high-voltage electrode and the arc-starting wire are in close contact, and ensure that the position of the root of the arc is on the bottom surface of the high-voltage electrode 15-1. Through the clamping effect of the high-voltage electrode 15-1, the arc-starting wire can achieve the effect of vertical tightening in the center, thereby avoiding the arc difference caused by the arc-starting wire affecting the test results and ensuring the repeatability of the test.

[0043] In another embodiment, a second arc-striking wire guide groove (not shown in the figure) is provided at the axial center of the low-voltage electrode 15 - 2 .

[0044] In this embodiment, the structures of the low voltage electrode and the high voltage electrode are the same and will not be described in detail here.

[0045] In another embodiment, a high-voltage incoming line 6 is disposed in the high-voltage incoming line bushing, and the high-voltage electrode 15 - 1 is vertically connected to the high-voltage incoming line 6 through threads.

[0046] In this embodiment, due to the vertical placement of the high-voltage electrode and the arc-starting wire, the arc generated by the discharge develops in the vertical direction, and the pressure wave caused by the arc in the oil is centered on the arc, propagating in the form of a cylindrical wave in the near field and a spherical wave in the far field. Since two directly opposite observation windows and at least one pressure sensor mounting flange need to be arranged on the side of the tank body, if the high-voltage electrode and the arc-starting wire are arranged horizontally, the pressure measurement result will definitely be blocked by the electrode, so the high-voltage electrode is not arranged horizontally.

[0047] It should be noted that by adjusting the length of the high-voltage incoming line and the length of the high-voltage electrode, the shortest gap between the high-voltage electrode and the low-voltage electrode is 20 mm and the longest is 80 mm, that is, the length of the arc in the oil is continuously adjustable between 20 mm and 80 mm. By adjusting the gap length, the characteristics of the arc in the oil of different lengths can be studied.

[0048] In another embodiment, a low-voltage outlet line 7 is disposed in the low-voltage outlet line bushing, and the low-voltage electrode 15 - 2 is vertically connected to the low-voltage outlet line 7 through threads.

[0049] In this embodiment, the low voltage electrode 15 - 2 is vertically connected to the low voltage outlet line 7 , and the principle is the same as the principle of vertically setting the high voltage electrode 15 - 1 , which will not be repeated here.

[0050] In another embodiment, the high-voltage measurement lead 12 is connected to the root of the high-voltage electrode 15 - 1 through a high-voltage measurement lead bushing 11 .

[0051] In this embodiment, the high-voltage measurement lead 12 is directly connected to the root of the high-voltage electrode 15-1, so that the arc voltage measurement point is directly connected to the root of the arc, so that the measurement point can be led out to the outside of the discharge tank 5 through the high-voltage measurement lead 12 and the high-voltage measurement lead sleeve 11, and the voltage change at both ends of the arc can be directly obtained, avoiding the influence of the resistance and inductance contained in the longer wire between the high-voltage probes on the measurement results.

[0052] In another embodiment, the low voltage measurement lead 14 is connected to the root of the low voltage electrode 15 - 2 through a low voltage measurement lead sleeve 13 .

[0053] In this embodiment, similarly, by connecting the low-voltage measurement lead 14 to the root of the low-voltage electrode 15-2 through the low-voltage measurement lead sleeve 13, the measurement point can be led out to the outside of the discharge tank 5 through the low-voltage measurement lead 14 and the low-voltage measurement lead sleeve 13, and the voltage change at both ends of the arc can be directly obtained, avoiding the influence of the resistance and inductance contained in the longer wire between the high-voltage probes on the measurement results.

[0054] In another embodiment, a pressure sensor mounting flange 16 is further provided on the discharge tank body 5 at a side opposite to the high-voltage measurement lead sleeve 11 and the low-voltage measurement lead sleeve 13 , and a pressure sensor is mounted on the pressure sensor mounting flange 16 .

[0055] In this embodiment, when the pressure wave reaches the sensor, it is not hindered by the electrode or the sensor mounting bracket, and the pressure waveform is obtained more realistically. According to the requirements of the measurement position, there are two ways to install the pressure sensor: (1) fix it to the flange through the sensor's own thread; (2) set a dynamic sealing structure on the sensor flange, and set an adjustment rod in the dynamic sealing structure, and the distance from the sensor pressure sensing surface to the arc center can be adjusted by the adjustment rod. In addition, there are two ways to arrange the pressure measurement points: (1) arrange a single sensor in a discharge. This method can study the pressure change at a fixed position under different discharge parameters; (2) arrange multiple sensors at multiple points. This method can obtain pressure data at different positions during the same discharge process, which can study both the pressure distribution law and the pressure attenuation law at different distances.

[0056] In another embodiment, the gas collecting device includes a needle valve 1, a buffer gas bottle 2, a trace gas pump 3 and a drainage gas collecting tank 4 which are connected in sequence.

[0057] In this embodiment, the gas generated by the discharge in the discharge tank is discharged through the gas outlet, and is transported to the buffer gas bottle 2 with a volume of 1L through the needle valve and the gas pipe with an inner diameter of 6.5mm, and then discharged into the drainage gas collecting tank 4 through the micro gas pump 3 with a flow rate of 2L / min. The volume of the measuring cylinder in the drainage gas collecting tank 4 can be pre-selected according to the discharge energy, and the inside is filled with water, and the gas generated by the discharge of the discharge tank is collected by using the drainage gas collecting method.

[0058] Since the gas generated by transformer oil is insoluble in water and the gas production is within an appropriate range, this embodiment adopts the water drainage gas collection method and collects the gas generated by discharge through a measuring cylinder. The volume of the gas production is obtained based on the reading of the measuring cylinder. Compared with the use of a gas collecting cylinder, the accuracy and intuitiveness of the gas volume measurement can be greatly increased.

[0059] In another embodiment, an observation window 10 is further provided on a side of the discharge tank body 5 adjacent to the pressure sensor mounting flange 16 .

[0060] In this embodiment, the diameter of the observation window 10 is 220 mm, and it is fixed to the discharge tank body 5 through a flange, and the flange is fixed and sealed by bolts. After one discharge is completed, the observation window flange can serve as a hand hole to facilitate the replacement of the arc-starting wire.

[0061] The present invention provides a test platform that is easy to operate and can be used for optical observation based on the drawbacks of the current oil arc discharge test platform. The gas collection platform has the advantages of simple structure and intuitive effect. The invention can be used for the study of the arc mechanism in oil and the study of arc decomposition gas, saving test costs, being simple and easy to operate, and being easy to promote and use.

[0062] The description and application of the present disclosure are illustrative and are not intended to limit the scope of the present disclosure to the above-described embodiments. Variations and changes to the embodiments disclosed herein are possible, and replacements of the embodiments and various equivalent components are known to those of ordinary skill in the art. It should be clear to those of ordinary skill in the art that the present disclosure may be implemented in other forms, structures, arrangements, proportions, and with other components, materials, and parts without departing from the spirit or essential features of the present disclosure. Other variations and changes may be made to the embodiments disclosed herein without departing from the scope and spirit of the present disclosure.

Claims

1. A transformer oil arc discharge observation and gas collection device, comprising: Discharge tank, A high-voltage measuring lead sleeve and a low-voltage measuring lead sleeve are provided on one side of the discharge tank body. A high-voltage measuring lead is provided in the high-voltage measuring lead sleeve, and the high-voltage measuring lead is connected to the root of the high-voltage electrode through the high-voltage measuring lead sleeve; a low-voltage measuring lead is provided in the low-voltage measuring lead sleeve, and the low-voltage measuring lead is connected to the root of the low-voltage electrode through the low-voltage measuring lead sleeve; A high-voltage incoming line bushing is arranged at the top of the discharge tank body, a high-voltage incoming line is arranged inside the high-voltage incoming line bushing, and a low-voltage outgoing line bushing is arranged at the bottom; The discharge tank is provided with a discharge electrode, which includes a high-voltage electrode and a low-voltage electrode; The top of the high-voltage electrode is provided with a mounting thread, and the high-voltage electrode is fixedly connected to the high-voltage incoming line through the mounting thread; the high-voltage electrode is provided with an arc-striking wire tightening screw hole, and the arc-striking wire is wound around the mounting bolt and screwed into the arc-striking wire tightening screw hole; the axial center of the high-voltage electrode is provided with a first arc-striking wire guide groove, so that the arc-striking wire is fixed in the high-voltage electrode to ensure that the position of the arc-striking wire is fixed during each test; a fastening ring is installed outside the high-voltage electrode to ensure that the high-voltage electrode and the arc-striking wire are in close contact and that the root of the arc is located on the bottom surface of the high-voltage electrode; the clamping effect of the high-voltage electrode is used to make the arc-striking wire achieve the effect of vertical tightening in the center, thereby avoiding the arc difference caused by the arc-striking wire affecting the test results and ensuring the repeatability of the test; The discharge tank body is also provided with a gas outlet, and the gas outlet is connected to a gas collecting device for collecting gas generated by discharge of the discharge tank body; Wherein, a second arc-starting wire guide groove is provided at the axial center of the low-voltage electrode; A low-voltage outlet line is arranged in the low-voltage outlet line casing, and the low-voltage electrode is connected to the low-voltage outlet line; The distance between the high voltage electrode and the low voltage electrode is 20mm - 80mm; An observation window is also provided on the side of the discharge tank body adjacent to the pressure sensor mounting flange; The gas collection device comprises a needle valve, a buffer gas bottle, a micro gas pump and a drainage gas collecting tank connected in sequence; and, The gas collection device can intuitively and effectively collect and measure the volume of the generated gas.

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