Method for improving breakdown voltage of metal particles near insulator and test system

Abstract

The present invention relates to a method for increasing the lifting voltage of metal particles near an insulator and a test system, which is characterized in that: it includes the following steps: Step 1, pre-treat the surface of the insulator sample; Step 2, coarsen the pre-treated insulator sample at room temperature to obtain an insulator capable of increasing the lifting voltage of metal particles. The present invention uses an insulator surface coarsening device to coarsen the surface of the insulator, changes the surface roughness of the insulator through sandpaper, does not introduce new interfaces, can reduce the adverse effects on the insulation system, and improves the reliability of the insulation system.

Description

Technical Field

[0001] The present invention belongs to the technical field of protection of DC gas-insulated transmission lines, and relates to a method for increasing the lifting voltage of metal particles and a test system, in particular to a method for increasing the lifting voltage of metal particles near an insulator and a test system. Background Art

[0002] DC gas-insulated transmission lines (GIL) have great application prospects in the fields of UHV power transmission, urban substations, and offshore converter stations due to their advantages of environmental friendliness, strong transmission capacity, low energy loss, strong anti-interference ability, and high reliability. However, during the production, assembly, and operation processes, metal particles will inevitably exist inside the GIL cavity. The metal particles will move under the action of an electric field, causing local disturbance to the steady-state electric field. In addition, due to the irregular shape of the particles, ionization is more likely to occur around them, introducing charges into the cavity. The accumulation of these charges on the surface of the insulator can easily lead to local electric field distortion, greatly increasing the probability of surface flashover, and thus triggering insulation failure. Because the movement of metal particles in DC GIL is likely to cause phenomena such as surface flashover, and then trigger accidents, studying the method for increasing the lifting voltage of metal particles is of great significance for the protection design of DC GIL.

[0003] Currently, the methods for suppressing the lifting voltage of metal particles mainly include electrode coating, pre-buried electrodes in insulators, particle traps, etc.

[0004] Among them, the heat-resistant temperature of the coating material is not high and cannot meet the temperature requirements of high-voltage and large-current systems. In addition, the bonding performance between the film and the electrode is poor. In application, adhesives need to be used to ensure good contact, and the adhesives have obvious disadvantages: ① poor stability, the thermal expansion coefficients between the film and the metal conductor differ greatly, and the long-term high-temperature operating environment is likely to cause the film to fall off, which may trigger insulation accidents such as gap breakdown; ② the adhesive will affect the heat dissipation of the conductor, resulting in an increase in the temperature of the electrode and the film, reducing the service life of the adhesive layer and the film; ③ introducing more interfaces makes the electric field distribution on the conductor surface uneven, easily causing interface flashover or micro-discharge, and reducing the insulation strength.

[0005] Pre-buried electrodes in insulators require the electrodes to be placed inside the insulators during the production process of the insulators. The installation, maintenance, and replacement of the electrodes are extremely inconvenient. In addition, the cost of this method is also relatively high. In addition, although the pre-buried electrodes can prevent conductive particles from approaching the insulator, they have almost no effect on the penetrating movement.

[0006] While forming a low electric field strength area at the bottom, the particle trap also causes an increase in the electric field strength at the top and distortion of the surrounding electric field. The increase in the electric field strength at the edge of the trap's sharp corners is the most severe, and the affected range increases with the increase in the trap width, which may lead to a decrease in the lifting voltage of the particles. Secondly, the trapping effect of the trap on linear and dust-like metal particles is average, especially for large linear particles and dust particles in DC transmission systems. In addition, the particle trap has a poor inhibitory effect on the movement of penetrating particles.

[0007] Therefore, how to develop a method for increasing the lifting voltage of metal particles near insulators and a test system that can significantly increase the lifting voltage of metal particles near insulators while ensuring the reliability of the insulation system and is easy to operate is a technical problem that needs to be solved urgently by those skilled in the art.

[0008] After retrieval, no published patent documents identical or similar to the present invention were found. Summary of the Invention

[0009] The purpose of the present invention is to overcome the deficiencies of the prior art and propose a method for increasing the lifting voltage of metal particles near insulators and a test system, which can increase the lifting voltage of metal particles in DC GIL while ensuring the reliability of the insulation system.

[0010] The present invention solves its practical problems by adopting the following technical solutions:

[0011] A method for increasing the lifting voltage of metal particles near insulators includes the following steps:

[0012] Step 1: Pretreat the surface of the insulator sample;

[0013] Step 2: Roughen the pretreated insulator sample at room temperature to obtain an insulator that can increase the lifting voltage of metal particles.

[0014] Moreover, the specific steps of Step 1 include:

[0015] (1) Prepare an industrial-grade pot insulator sample, which is composed of micron-sized aluminum oxide and epoxy resin casting;

[0016] (2) Pretreat the surface of the insulator sample prepared in step (1) to remove surface dirt and keep it clean.

[0017] Moreover, the specific steps of Step 2 include:

[0018] (1) Face the front of a 2000-mesh sandpaper with dimensions of 7 cm × 4 cm towards the insulator sample to be roughened, and paste the back on an aluminum alloy gasket with dimensions of 7 cm × 4 cm × 0.5 cm through hot melt adhesive. The back of this aluminum alloy gasket is welded to one end of a screw;

[0019] (2) Select a spring with an elastic coefficient of 100 N / m and a length of 30 cm, and install it on the screw. One end of the spring is connected to the aluminum alloy gasket, and the other end is connected to the bracket; set an inclined round hole with a horizontal line angle of 45 degrees and a radius of 0.5 cm on the bracket, and the other end of the screw passes through the inclined round hole on the bracket; thread a nut for compressing the spring on the screw, compress the spring to 10 cm by tightening the nut on the screw, place a gasket between the nut and the bracket, and fixedly install both ends of the telescopic rod with a maximum telescopic length of 30 cm and a minimum telescopic length of 5 cm on the aluminum alloy gasket and the bracket respectively to keep the aluminum alloy gasket from rotating;

[0020] (3) Fix the rotating motor on the experimental platform by bolts, weld the central axis of the rotating motor to the insulator pad, and fix both ends of the insulator on the insulator pad by bolts;

[0021] (4) Loosen the nut to make the spring length 14 - 16 cm, and let the 2000 - mesh sandpaper with a size of 7 cm × 4 cm contact the surface of the rotating insulator, with the pressure between the sandpaper and the insulator surface being 14 - 16 N.

[0022] (5) Control the rotating motor to drive the insulator to rotate around the central axis at a speed of 58 - 62 revolutions per minute for roughening the surface of the insulator, and the roughening treatment time is 30 - 32 minutes.

[0023] A device for roughening an insulator sample at room temperature includes: an aluminum alloy gasket, on one side end face of which sandpaper is adhered for roughening the surface of the insulator; on the other side end face of the aluminum alloy gasket, a screw is fixedly installed, and a spring is sleeved on the screw. One end of the spring is connected to the aluminum alloy gasket, and the other end is connected to the bracket; the other end of the screw penetrates through the bracket and is threadedly connected to a nut, and the nut is used for compressing the spring.

[0024] Moreover, at the corresponding position of the bracket, an inclined round hole with a horizontal line angle of 45 degrees and a radius of 0.5 cm is made, and the other end of the screw passes through the inclined round hole on the bracket; a gasket is coaxially sleeved below the nut; a telescopic rod is fixedly installed between the aluminum alloy gasket and the bracket on one side of the screw; the insulator is installed on the insulator pad and fixed by bolts, and a rotating motor is connected below the insulator pad, and the rotating motor is installed on the experimental platform.

[0025] A lifting voltage test system for metal particles includes: a cylindrical sealed gas chamber, which is used to simulate the operating environment of GIL, and a GIL model is arranged inside it for testing the lifting voltage of metal particles;

[0026] Moreover, one end of the cylindrical sealed gas chamber is connected to a high-voltage DC power supply, and the other end is grounded, which is used to provide power input for the test system. Two copper electrodes are installed on the inner end faces of the upper and lower sides of the cylindrical sealed gas chamber. The upper electrode is connected to the high-voltage DC power supply, and the lower electrode is grounded. The upper electrode is connected to the high-voltage DC power supply through a wire, and a cylindrical insulator is sleeved on the wire. The cylindrical insulator is fixedly installed above the cylindrical sealed gas chamber by bolts, which is used to keep insulation from the cylindrical sealed gas chamber. One end of the high-voltage DC power supply is connected to the cylindrical sealed gas chamber through a resistor. A distance adjustment knob is installed below the cylindrical sealed gas chamber, and a micrometer is equipped, which is used to adjust the position of the lower electrode. A barometer for detecting the gas pressure in the cavity is installed above the cylindrical sealed gas chamber. The cylindrical sealed gas chamber has two gas interfaces. The lower interface is connected to a gas pipe through a quick connector for the gas pipe. The gas pipe is connected to a vacuum pump through a quick connector for the gas pipe to carry out air extraction and air release to realize the change of the air pressure in the gas chamber. The left interface is connected to a gas pipe through a quick connector for the gas pipe. The gas pipe is connected to a gas cylinder through a quick connector for the gas pipe, which is used to fill SF6.

[0027] Moreover, the GIL model includes: a central conductor, a ground electrode and a pot-type insulator. Among them, the central conductor is connected to the upper electrode of the cylindrical sealed gas chamber. The ground electrode is placed on the lower electrode of the cylindrical sealed gas chamber. The pot-type insulator is coaxially sleeved on the ground electrode to play a role in support and insulation. A quartz window is installed on the side of the cylindrical sealed gas chamber, which is aligned with the convex side of the pot-type insulator in the GIL model. An LED lamp and a high-speed camera are also arranged in the cylindrical sealed gas chamber. The high-brightness LED lamp is installed inside the cylindrical sealed gas chamber to illuminate the inside of the GIL model. The high-speed camera is directly opposite and installed on the quartz window on the side of the cylindrical sealed gas chamber. Metal particles are placed on the ground electrode of the GIL model.

[0028] Advantages and beneficial effects of the present invention:

[0029] 1. The present invention uses a roughening treatment device for the surface of the insulator to roughen the surface of the insulator. By using sandpaper to change the surface roughness of the insulator, no new interface is introduced, which can reduce the adverse effects on the insulation system and improve the reliability of the insulation system. However, the existing electrode film coating method will introduce multiple interfaces, resulting in uneven electric field distribution on the conductor surface, which is prone to interface flashover or microdischarge, reducing the insulation strength.

[0030] 2. The insulator surface roughening treatment device of the present invention realizes the pressure applied between the sandpaper and the insulator to be 14 - 16 N by loosening the nut to make the spring length 14 - 16 cm, and at the same time keeps the insulator rotating at a fixed speed, thereby changing the surface roughness. Compared with the method of pre-burying electrodes in the insulator, which has the defect that the installation, maintenance and replacement of electrodes are extremely inconvenient, the operation of the present invention is convenient and the manufacturing cost is low.

[0031] 3. The insulator surface roughening treatment device of the present invention does not introduce new structures, so it will not cause electric field distortion, and significantly increases the lifting voltage of metal particles near the insulator, overcoming the defect of the traditional particle trap method that while forming a low electric field strength area at the bottom, it will also cause an increase in the electric field strength at the top and distortion of the surrounding electric field.

[0032] 4. The air pressure application range of the metal particle lifting voltage test system of the present invention is from -0.1 Mpa to 1 Mpa, which can be used for various air pressures; it can solve the problem of difficult simulation of metal particle lifting experiments under multi-air pressure conditions;

[0033] 5. The GIL module in the metal particle lifting voltage test system of the present invention is of a coaxial cylinder structure, which is consistent with the shape of the GIL electrode in the actual situation, compensating for the deficiency of using flat electrodes to simulate GIL electrodes in the existing experimental devices.

[0034] 6. In the metal particle lifting voltage test system of the present invention, the influence of the distance from the basin insulator on the jumping characteristics of metal particles can be considered. The metal particles are observed by a high-speed camera with millisecond-level time accuracy, and the voltage when the metal particles start to move, that is, the lifting voltage, is recorded. However, the existing experimental devices do not consider the influence of the basin insulator on the lifting voltage of metal particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the size of the basin insulator adopted in the present invention;

[0036] Figure 2 It is a structural diagram of the insulator surface roughening treatment device provided by the specific embodiment of the present invention;

[0037] Figure 3 It is a composition diagram of the metal particle lifting voltage test system provided by the specific embodiment of the present invention;

[0038] Figure 4 It is a spherical metal particle diagram taken by the present invention;

[0039] Figure 5 It is a linear metal particle diagram taken by the present invention;

[0040] Figure 6This is the lifting voltage diagram of spherical metal particles near the insulator after the surface of the pot-type insulator of the present invention is roughened;

[0041] Figure 7 This is the lifting voltage diagram of linear metal particles near the insulator after the surface of the pot-type insulator of the present invention is roughened;

[0042] Figure 8 This is the comparison diagram of the surface morphology of the pot-type insulator after the surface of the pot-type insulator of the present invention is roughened, the untreated pot-type insulator, and the surface morphology of the pot-type insulator using the roughening treatment technology in the prior art.

[0043] Explanation of reference numerals:

[0044] 1 - High-voltage DC power supply; 2 - Resistor; 3 - Cylindrical insulator; 4 - Pressure gauge; 5 - Gas interface; 6 - Upper electrode; 7-1 - High-brightness LED lamp; 7-2 - High-speed camera; 8 - GIL model: 8-1 - Pot-type insulator, 8-2 - Central conductor, 8-3 - Ground electrode; 9 - SF6 gas cylinder; 10 - Micrometer; 11 - Distance adjustment knob; 12 - Vacuum pump; 13 - Cylindrical sealed gas chamber; 14 - Quartz window; 15 - Lower electrode; 16 - Insulator; 17 - Bolt; 18 - Insulator pad; 19 - Rotating motor; 20 - Experimental platform; 21 - 2000-mesh sandpaper; 22 - Aluminum alloy gasket; 23 - Spring; 24 - Support; 25 - Gasket; 26 - Nut; 27 - Screw; 28 - Telescopic rod. Detailed implementation manners

[0045] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0046] A method for increasing the lifting voltage of metal particles near an insulator includes the following steps:

[0047] Step 1, pre-treat the surface of the insulator sample;

[0048] The specific steps of Step 1 include:

[0049] (1) Prepare an industrial-grade pot-type insulator sample, which is composed of micron-scale aluminum oxide and epoxy resin casting, and the specific dimensions are as Figure 1 shown, with the unit of mm;

[0050] (2) Pre-treat the surface of the insulator sample prepared in step (1) to remove surface dirt and keep it clean;

[0051] The specific steps of step (2) of Step 1 include:

[0052] ① Ultrasonically treat the insulator sample in step (1) of Step 1 in anhydrous ethanol and distilled water for 120 - 140 minutes to remove the dirt on the surface of the sample;

[0053] ② Dry the decontaminated sample in a vacuum oven at 70-75°C for 60-70 minutes to remove moisture.

[0054] Step 2: roughening the insulator sample pretreated in step 1 at room temperature to obtain an insulator capable of increasing the starting voltage of the metal particles.

[0055] The specific steps of step 2 include:

[0056] (1) Place a 2000-grit sandpaper with a size of 7 cm × 4 cm, with its front side facing the insulator sample to be roughened, and adhere its back side to an aluminum alloy washer with a size of 7 cm × 4 cm × 0.5 cm using hot melt adhesive. The back side of the aluminum alloy washer is welded to one end of the screw.

[0057] (2) A spring with an elastic modulus of 100 N / m and a length of 30 cm is selected and installed on the screw. One end of the spring is connected to the aluminum alloy washer, and the other end is connected to the bracket. An inclined circular hole with a horizontal angle of 45 degrees and a radius of 0.5 cm is set on the bracket, and the other end of the screw passes through the inclined circular hole on the bracket;

[0058] A nut for compressing the spring is threadedly connected to the screw rod. The spring is compressed to 10 cm by tightening the nut on the screw rod. A gasket is placed between the nut and the bracket. The ends of the telescopic rod with a maximum telescopic length of 30 cm and a minimum telescopic length of 5 cm are fixed to the aluminum alloy gasket and the bracket respectively to prevent the aluminum alloy gasket from rotating.

[0059] (3) Fix the rotating motor to the experimental platform with bolts, weld the central axis of the rotating motor to the insulator pad, and fix the two ends of the insulator to the insulator pad with bolts;

[0060] (4) Loosen the nut so that the spring length is 14-16 cm and the 2000-grit sandpaper with a size of 7 cm × 4 cm contacts the surface of the rotating insulator, where the pressure between the sandpaper and the insulator surface is 14-16 N.

[0061] (5) Control the rotating motor to drive the insulator to rotate around the central axis at a speed of 58-62 revolutions per minute to perform surface roughening treatment on the insulator. The roughening treatment time is 30-32 minutes.

[0062] A device for roughening an insulator sample at room temperature, such as Figure 2As shown in the figure, it includes: an aluminum alloy gasket, on one side end face of which there is a sandpaper adhered for roughening the surface of the insulator; on the other side end face of the aluminum alloy gasket, a screw rod is fixedly installed, and a spring is sleeved on the screw rod, one end of the spring is connected to the aluminum alloy gasket, and the other end is connected to the bracket; the other end of the screw rod penetrates through the bracket and is threadedly connected with a nut, and this nut is used to compress the spring.

[0063] In this embodiment, at the corresponding position of the bracket, there is an inclined round hole with a horizontal line included angle of 45 degrees and a radius of 0.5 cm, and the other end of the screw rod passes through the inclined round hole on the bracket;

[0064] In this embodiment, a gasket is coaxially sleeved below the nut.

[0065] In this embodiment, a telescopic rod is fixedly installed between the aluminum alloy gasket and the bracket on one side of the screw rod.

[0066] In this embodiment, the insulator is installed on an insulator pad and fixed by bolts, and a rotating motor is connected below the insulator pad, and this rotating motor is installed on an experimental platform.

[0067] The working process of the surface roughening treatment device for the pot-shaped insulator is as follows:

[0068] The 2000-mesh sandpaper with a size of 7 cm × 4 cm has its front face facing the insulator sample to be roughened, and its back face is adhered to the aluminum alloy gasket with a size of 7 cm × 4 cm × 0.5 cm through hot-melt adhesive. The back face of this aluminum alloy gasket is welded to one end of the screw rod. There is an inclined round hole with a horizontal line included angle of 45 degrees and a radius of 0.5 cm in the bracket, and the other end of the screw rod passes through this inclined round hole. By rotating the nut to compress the spring, the gasket is placed between the bracket and the nut, and both ends of the telescopic rod are welded to the aluminum alloy gasket and the bracket respectively to keep the aluminum alloy gasket from rotating. Among them, the included angle between the telescopic rod and the bracket is 45 degrees, and the included angle between the telescopic rod and the aluminum alloy gasket is 90 degrees. Then, both ends of the spring are welded to the aluminum alloy gasket and the bracket respectively, and the bracket is fixed to the experimental platform by bolts.

[0069] The rotating motor is fixed to the horizontal experimental platform by bolts, and the insulator is fixed to the insulator pad by bolts. The rotating motor is used to drive the insulator pad and the insulator to rotate, so as to realize the surface roughening treatment of the pot-shaped insulator.

[0070] Its working principle is as follows:

[0071] Compress the spring to 10 cm by tightening the nut. Fix the motor to the horizontal experimental platform with bolts, and fix the insulator to the insulator pad with bolts. Loosen the nut to make the spring length 14 - 16 cm, so that the pressure between the sandpaper and the insulator is 14 - 16 N. Rotate the motor to drive the insulator pad and the insulator to rotate at a speed of 58 - 62 revolutions per minute to achieve roughening treatment.

[0072] In this embodiment, the experimental data in Table 1 verify that after the surface of the pot - type insulator is roughened, the lifting voltage of spherical metal particles can be effectively increased.

[0073] A test system for the lifting voltage of metal particles, as Figure 3 shown, includes: a cylindrical sealed gas chamber, which is used to simulate the operating environment of GIL, and a GIL model is arranged inside it for testing the lifting voltage of metal particles;

[0074] In this embodiment, one end of the cylindrical sealed gas chamber is connected to a high - voltage DC power supply, and the other end is grounded, which is used to provide power input for the test system.

[0075] In this embodiment, two copper electrodes are installed on the inner end faces of the upper and lower sides of the cylindrical sealed gas chamber. The upper - side electrode is connected to the high - voltage DC power supply, and the lower - side electrode is grounded;

[0076] In this embodiment, the upper - side electrode is connected to the high - voltage DC power supply through a wire, and a cylindrical insulator is sleeved on the wire. The cylindrical insulator is fixedly installed above the cylindrical sealed gas chamber by bolts, which is used to keep insulation from the cylindrical sealed gas chamber.

[0077] In this embodiment, one end of the high - voltage DC power supply is connected to the cylindrical sealed gas chamber through a resistor.

[0078] In this embodiment, an adjusting knob is installed below the cylindrical sealed gas chamber, and a micrometer is equipped, which is used to adjust the position of the lower - side electrode. A barometer for detecting the gas pressure in the cavity is installed above the cylindrical sealed gas chamber.

[0079] In this embodiment, the cylindrical sealed gas chamber has two gas interfaces. The lower - side interface is connected to a gas pipe through a quick - coupling of the gas pipe. The gas pipe is connected to a vacuum pump through a quick - coupling of the gas pipe for air extraction and air release to realize the change of the air pressure in the chamber; the left - hand interface is connected to a gas pipe through a quick - coupling of the gas pipe, and the gas pipe is connected to a gas cylinder through a quick - coupling of the gas pipe for filling SF6.

[0080] In this embodiment, the GIL model includes: a central conductor, a ground electrode, and a pot insulator; where the central conductor is connected to the upper electrode of the cylindrical sealed gas chamber, the ground electrode is placed on the lower electrode of the cylindrical sealed gas chamber, and the pot insulator is coaxially sleeved on the ground electrode to play a supporting and insulating role;

[0081] In this embodiment, a quartz window is installed on the side of the cylindrical sealed gas chamber, aligned with the convex side of the pot insulator in the GIL model. An LED lamp and a high-speed camera are also provided in the cylindrical sealed gas chamber. The high-brightness LED lamp is installed inside the cylindrical sealed gas chamber to illuminate the inside of the GIL model; the high-speed camera is directly opposite to the quartz window installed on the side of the cylindrical sealed gas chamber, and metal particles are placed on the ground electrode of the GIL model.

[0082] In this embodiment, the beneficial effects of the present invention are verified through experiments:

[0083] The particle lifting images are taken by the lifting voltage test system of metal particles. The lifting voltages of spherical metal particles at distances of 0 mm and 10 mm from the insulator are measured respectively by the lifting voltage test system of metal particles. The surface morphology of the samples before and after fluorination is measured by a field emission scanning electron microscope (Nova Nano SEM450).

[0084] Figure 4 It is the taken lifting image of spherical metal particles, as Figure 4 shown:

[0085] Through the lifting voltage test system of metal particles, the movement of spherical metal particles can be clearly photographed.

[0086] Figure 5 It is the taken lifting image of linear metal particles, as Figure 5 shown:

[0087] Through the lifting voltage test system of metal particles, the movement of linear metal particles can be clearly photographed.

[0088] Figure 6 It is the lifting voltage of spherical metal particles near the roughened pot insulator in an SF6 environment, as Figure 6 shown:

[0089] In an SF6 environment of 0.2 MPa, ten lifting experiments are respectively carried out on spherical metal particles near the roughened pot insulator at two cases of distances of 0 mm and 10 mm from the pot insulator. The time interval between every two experiments is 5 hours. After the insulator is roughened, the problem of low lifting voltage of spherical metal particles can be improved. The experimental results prove that the pot insulator after the roughening treatment of the present invention can significantly make the spherical metal particles have a higher lifting voltage.

[0090] Figure 7 is the lifting voltage of linear metal particles near the roughened pot insulator in an SF6 environment, as Figure 7 shown below:

[0091] In an SF6 environment of 0.2 MPa, spherical metal particles near the roughened pot insulator were subjected to ten lifting experiments at two distances of 0 mm and 10 mm from the pot insulator respectively. The time interval between every two experiments was 5 hours. After the insulator was roughened, the problem of low lifting voltage of linear metal particles could be improved. The experimental results proved that the pot insulator after the roughening treatment of the present invention could significantly make the linear metal particles have a higher lifting voltage.

[0092] Figure 8 This is a comparison diagram of the surface morphology of the roughened pot insulator of the present invention and the surface morphology of the prior art. It was found that the surface morphology of the existing roughening treatment technology was in a gully shape, and the distribution of its protrusions and depressions was uneven. The surface structure of the sample after the roughening treatment of the present invention had relatively compact sharp protrusions and depressions, and the distribution of the protrusions and depressions was relatively uniform, and the surface roughness of the pot insulator increased significantly.

[0093] Table 1 is a chart of the leakage current and the lifting voltage of metal particles near the insulator after the surface roughening of the pot insulator of the present invention. It was found that after the roughness treatment, the leakage current on the surface of the pot insulator was greatly increased, and at the same time, the lifting voltages of spherical metal particles and linear metal particles were increased. And when the distance between the metal particle and the insulator was 0 mm, the lifting voltage improvement effect was more obvious.

[0094]

[0095]

[0096] The innovation of the present invention lies in:

[0097] (1) Compared with the existing electrode film covering method, multiple interfaces make the electric field distribution on the conductor surface uneven, which is easy to cause interface flashover or micro-discharge, reducing the insulation strength. The insulator surface roughening treatment technology of the present invention can reduce the adverse effects on the insulation system and improve the reliability of the insulation system;

[0098] (2) Compared with the method of embedding electrodes in the insulator, the installation, maintenance and replacement of the electrodes are extremely inconvenient. The insulator surface roughening treatment technology of the present invention is easy to operate and reduces costs;

[0099] (3) Compared with the particle trap method, while forming a low electric field strength area at the bottom, it will also cause an increase in the electric field strength at the top and distortion of the surrounding electric field. The insulator surface roughening treatment technology of the present invention will not cause electric field distortion and significantly increases the lifting voltage of metal particles near the insulator.

[0100] (4) The air pressure application range of the lifting voltage test system for the metal particles of the present invention is from -0.1 Mpa to 1 Mpa, which can be used for various air pressures; it can solve the problem of difficult simulation of the metal particle lifting experiment under multi-air pressure conditions;

[0101] (5) The GIL module in the lifting voltage test system for the metal particles of the present invention can imitate the shape of the GIL electrode in the real situation, compensating for the deficiency of using a flat electrode to simulate the GIL electrode in the existing experimental devices;

[0102] (6) In the lifting voltage test system for the metal particles of the present invention, the influence of the distance from the basin insulator on the take-off characteristics of the metal particles can be considered. Through the voltage display of the high-speed camera and the DC power supply, the lifting voltage of the metal particles can be accurately measured, while the influence of the basin insulator on the take-off voltage of the metal particles is not considered in the existing experimental devices.

[0103] (7) The roughening treatment technology of the present invention is for the DC GIL / GIS field. Due to the transportation, assembly, operation and maintenance of the equipment, metal particles inevitably exist. The increase of the lifting voltage of the metal particles has always been considered an effective means to improve the operation reliability of the power transmission and transformation equipment. The roughening treatment technology of the present invention can effectively increase the lifting voltage of the metal particles. However, some existing roughening treatment means can only be used to increase the flashover voltage of insulating materials, and are usually applied to the aerospace insulation field. But in the DC GIL / GIS field, the harm of metal particles cannot be ignored. Improving the lifting voltage of metal particles can improve the operation reliability of DC GIL / GIS.

[0104] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0105] The present application is described by referring to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowcharts and / or block diagrams, and the combination of processes and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate for realizing in the process Figure 1means for the functions specified in one or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks

[0106] These computer program instructions may also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured article including an instruction means, and the instruction means implements the processes Figure 1 means for the functions specified in one or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks

[0107] These computer program instructions may also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 means for the functions specified in one or more processes and / or blocks Figure 1 means for the functions specified in one or more blocks

Claims

1. A metal particle trigger voltage test system, characterized by: include: A cylindrical sealed air chamber is used to simulate the operating environment of the GIL. A GIL model is set in the cylindrical sealed air chamber for the starting voltage test of the metal particles; One end of the cylindrical sealed air chamber is connected to a high-voltage DC power supply, and the other end is grounded, so as to provide power input for the test system; two copper electrodes are installed on the upper and lower inner end surfaces of the cylindrical sealed air chamber, wherein the upper electrode is connected to the high-voltage DC power supply and the lower electrode is grounded; the upper electrode is connected to the high-voltage DC power supply through a wire, and a cylindrical insulator is mounted on the wire, and the cylindrical insulator is fixed above the cylindrical sealed air chamber by bolts to maintain insulation from the cylindrical sealed air chamber; one end of the high-voltage DC power supply is connected to the cylindrical sealed air chamber through a resistor The cylindrical sealed air chamber is provided with a pitch adjustment knob installed below and a micrometer screw for adjusting the position of the lower electrode. A barometer for detecting the gas pressure in the cavity is installed above the cylindrical sealed air chamber. The cylindrical sealed air chamber is provided with two gas interfaces. The lower interface is connected to the air guide tube through a trachea quick connector. The air guide tube is connected to the vacuum pump through a trachea quick connector for pumping and deflation to achieve changes in the air pressure in the air chamber. The left interface is connected to the air guide tube through a trachea quick connector. The air guide tube is connected to the gas cylinder through a trachea quick connector for filling with SF6. The GIL model includes: a center conductor, a ground electrode, and a pot insulator. The center conductor is connected to the upper electrode of a cylindrical sealed air chamber, the ground electrode is placed on the lower electrode of the cylindrical sealed air chamber, and the pot insulator is coaxially mounted on the ground electrode to provide support and insulation. A quartz window is installed on the side of the cylindrical sealed air chamber, aligned with the convex side of the pot insulator in the GIL model. An LED light and a high-speed camera are also provided within the cylindrical sealed air chamber. The LED light is installed inside the cylindrical sealed air chamber to illuminate the interior of the GIL model. The high-speed camera faces the quartz window installed on the side of the cylindrical sealed air chamber. Metal particles are placed on the ground electrode of the GIL model.

2. A method for increasing the metal particle starting voltage near an insulator using the metal particle starting voltage testing system according to claim 1, characterized in that: The following steps are involved: Step 1, pre-treating the surface of the insulator sample; Step 2: roughening the insulator sample pretreated in step 1 at room temperature to obtain an insulator capable of increasing the starting voltage of the metal particles.

3. The method for increasing the starting voltage of metal particles near an insulator according to claim 2, characterized in that: The specific steps of step 1 include: (1) Prepare industrial-grade pot-type insulator samples, which are composed of micron-grade aluminum oxide and epoxy resin casting; (2) Pre-treating the surface of the insulator sample prepared in step (1) to remove surface dirt and keep it clean.

4. The method for increasing the starting voltage of metal particles near an insulator according to claim 2, characterized in that: The specific steps of step 2 include: (1) Place a 2000-grit sandpaper with a size of 7 cm × 4 cm, with its front side facing the insulator sample to be roughened, and adhere its back side to an aluminum alloy washer with a size of 7 cm × 4 cm × 0.5 cm using hot melt adhesive. The back side of the aluminum alloy washer is welded to one end of the screw. (2) A spring with an elastic coefficient of 100 N / m and a length of 30 cm is selected and installed on the screw rod. One end of the spring is connected to the aluminum alloy gasket, and the other end is connected to the bracket. An inclined circular hole with a horizontal angle of 45 degrees and a radius of 0.5 cm is set on the bracket, and the other end of the screw rod passes through the inclined circular hole on the bracket. A nut for compressing the spring is threadedly connected to the screw rod. The spring is compressed to 10 cm by tightening the nut on the screw rod. A gasket is placed between the nut and the bracket. The two ends of the telescopic rod with a maximum telescopic length of 30 cm and a minimum telescopic length of 5 cm are fixed to the aluminum alloy gasket and the bracket respectively to prevent the aluminum alloy gasket from rotating. (3) Fix the rotating motor to the experimental platform with bolts, weld the central axis of the rotating motor to the insulator pad, and fix the two ends of the insulator to the insulator pad with bolts; (4) Loosen the nut so that the spring length is 14-16 cm and the 2000-grit sandpaper with a size of 7 cm × 4 cm is in contact with the surface of the rotating insulator, where the pressure between the sandpaper and the insulator surface is 14-16 N; (5) Control the rotating motor to drive the insulator to rotate around the central axis at a speed of 58-62 revolutions per minute to perform surface roughening treatment on the insulator. The roughening treatment time is 30-32 minutes.

5. The method for increasing the starting voltage of metal particles near an insulator according to claim 4, characterized in that: The device for roughening the pretreated insulator sample at room temperature in step 1 comprises: an aluminum alloy gasket, one end surface of which is covered with sandpaper for roughening the surface of the insulator; a screw rod fixedly mounted on the other end surface of the aluminum alloy gasket, a spring sleeved on the screw rod, one end of the spring being connected to the aluminum alloy gasket and the other end being connected to the bracket; the other end of the screw rod passing through the bracket and being threadedly connected to a nut, the nut being used to compress the spring.

6. The method for increasing the starting voltage of metal particles near an insulator according to claim 4, characterized in that: An inclined circular hole with a horizontal angle of 45 degrees and a radius of 0.5 cm is formed at the corresponding position of the bracket, and the other end of the screw passes through the inclined circular hole on the bracket; a gasket is coaxially sleeved under the nut; a telescopic rod is fixed between the aluminum alloy gasket on one side of the screw and the bracket; the insulator is mounted on the insulator base and fixed by bolts, and a rotating motor is connected under the insulator base, and the rotating motor is mounted on the experimental platform.

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