Simulation analysis method for harm of metal foreign matter to GIS equipment

Abstract

The invention discloses a simulation analysis method for harm of a metal foreign body to GIS equipment, and belongs to the field of harm analysis of the metal foreign body to the GIS equipment, and the method comprises the following steps: S1, building a GIS bus model by using electromagnetic simulation software; s2, setting a simulation scene: determining the material, the shape and the setting position of the metal foreign body; s3, executing electric field simulation: running a simulation program, and drawing a field intensity distribution diagram and field intensity comparison diagrams under a plurality of running scenes; s4, based on the field intensity distribution diagram and the field intensity comparison diagram drawn in the step S3, searching the highest electric field intensity points under different materials, shapes and setting positions; and S5, based on the highest point of the electric field intensity, determining the damage degree of the metal foreign matter to the GIS bus model. By adopting the method for simulating and analyzing the harm of the metal foreign matters to the GIS equipment, the harm of the metal foreign matters to the GIS equipment can be comprehensively evaluated through accurate modeling and simulation, so that a powerful guarantee is provided for safe and stable operation of a power system.

Description

Technical Field

[0001] The invention relates to the technical field of analysis of the harm of metal foreign matter to GIS equipment, and in particular to a simulation analysis method of the harm of metal foreign matter to GIS equipment. Background Art

[0002] Metallic foreign matter may be generated during the entire life cycle of gas insulated switchgear (GIS) including production, operation, installation and maintenance. The movement of metallic foreign matter in GIS or its adsorption on the surface of basin insulators will cause local electric field distortion, trigger gas breakdown, and may even cause flashover along the basin insulators, reducing the reliability of equipment operation.

[0003] Specifically, the impact of metal foreign matter on GIS can be divided into four aspects: 1. When metal foreign matter moves near the pot insulator, it may introduce electric charge to the surface of the pot insulator and affect the stability of insulation; 2. When metal foreign matter falls on the surface of the wedge-shaped air gap, it will affect the shielding effect of the air gap, causing a great distortion of the original electric field distribution; 3. When metal foreign matter is adsorbed on the surface of the basin insulator, the insulation distance along the surface of the basin insulator will be shortened and additional charge will be introduced; 4. When metal foreign objects fall, there is a risk of arcing near high-voltage conductors.

[0004] In summary, metal foreign bodies greatly reduce the operational reliability of GIS equipment. However, the existing technology lacks analysis of the hazards of metal foreign bodies, which is not conducive to comprehensive assessment and prevention of potential risks. Summary of the invention

[0005] The purpose of the present invention is to provide a simulation analysis method for the damage of metal foreign matter to GIS equipment to solve the above technical problems.

[0006] To achieve the above object, the present invention provides a simulation analysis method for the damage of metal foreign matter to GIS equipment, comprising the following steps: S1. Use electromagnetic simulation software to establish a GIS busbar model; S2. Setting the simulation scene: determining the material, shape and location of the metal foreign body; S3, perform electric field simulation: in each simulation scenario determined in step S2, run the simulation program, draw a field strength distribution diagram and a field strength comparison diagram under multiple operation scenarios; S4, based on the field intensity distribution diagram and field intensity comparison diagram drawn in step S3, finding the highest point of electric field intensity under metal foreign bodies of different materials, shapes and setting positions; S5. Determine the degree of damage caused by metal foreign matter to the GIS busbar model based on the highest point of the electric field intensity.

[0007] Preferably, in step S1, a GIS busbar segment of a 550 kV DC GIS scaled test is simulated and modeled using COMSOL multi-physics simulation software to obtain a GIS busbar model, and the GIS busbar model includes a grounding shell, an air domain, a pot-type insulator arranged at the middle position inside the grounding shell, and two high-voltage conductors respectively arranged on both sides of the pot-type insulator; The air space is used to contain the gas insulation medium and provide insulation performance.

[0008] Preferably, the material of the outer side of the ground connection is aluminum alloy, with a tangent thermal expansion coefficient of 21.4 / K and a density of 2700kg / m 3 ; The gas insulation medium is SF6 gas with a density of 26.08kg / m 3 , the relative dielectric constant is 1.002; The material of the pot insulator is epoxy resin glue, with a density of 1673kg / m 3 , the relative dielectric constant is 4.

[0009] Preferably, the metal foreign body described in step S2 is made of aluminum or iron, and is in the shape of a block, a line or a sphere, and is disposed at the junction between the pot insulator and the high-voltage conductor, the surface of the pot insulator or the air gap between the pot insulator and the grounding shell.

[0010] Preferably, the metal foreign matter is embedded in the surface of the pot insulator.

[0011] Therefore, the present invention adopts the above-mentioned simulation analysis method of the harm of metal foreign matter to GIS equipment, which has the following beneficial effects: 1. Accurate modeling and simulation: COMSOL multi-physics simulation software can be used to accurately simulate the electric field distribution in the GIS busbar model. The simulation software can also be used to analyze in detail the impact of metal foreign bodies of different materials, shapes and positions on GIS equipment, thereby improving the accuracy of the simulation; 550kV DC GIS scaled-down test model: A scaled-down model of the same size as the actual equipment is used for simulation to ensure that the simulation results have a high reference value and can better reflect the actual situation; 2. Comprehensive parameter settings: Detailed material parameters: The specific materials and physical properties (such as density, thermal expansion coefficient, relative dielectric constant, etc.) of the grounding shell, gas insulation medium (SF6), and pot insulator are clarified. The precise setting of these parameters makes the simulation results more reliable and can more realistically reflect the actual working conditions; Various types of metal foreign bodies: metal foreign bodies of various materials (aluminum, iron) and shapes (block, wire, spherical) are considered, and different placement locations are set (such as the junction between the pot insulator and the high-voltage conductor, the surface of the pot insulator or the air gap). This diversity helps to comprehensively evaluate the degree of harm of different types of metal foreign bodies to GIS equipment; 3. Hazard level assessment: Determine the hazard based on the highest point of electric field strength: By drawing field strength distribution maps and comparison maps, find the points with the highest electric field strength under different conditions, and then assess the degree of hazard of metal foreign matter to GIS equipment. This method can not only intuitively display the impact of metal foreign matter, but also provide a scientific basis for subsequent safety measures; Special cases where foreign objects are embedded in the surface of pot insulators: Special attention should be paid to the case where foreign objects are embedded in the surface of pot insulators. This may be one of the most dangerous situations, because pot insulators are important insulating components in GIS equipment. Any damage may lead to serious failures. Through simulation analysis, such potential risks can be discovered and prevented in advance.

[0012] 4. Through simulation analysis of the impact of metal foreign matter, engineers can optimize the design and installation of GIS equipment and avoid introducing metal foreign matter that may cause problems in key areas.

[0013] In summary, the simulation analysis method of the harm of metal foreign matter to GIS equipment described in the present invention can comprehensively evaluate the harm of metal foreign matter to GIS equipment through precise modeling and simulation, thereby providing strong guarantee for the safe and stable operation of the power system; in this way, not only potential problems can be discovered in advance, but also equipment design and maintenance strategies can be optimized, the possibility of failure can be reduced, and the overall reliability of the power system can be improved.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a simulation analysis method of the harm of metal foreign matter to GIS equipment in the present invention; Figure 2 Schematic diagram of GIS busbar model for simulation verification; Figure 3 The electric field distribution diagram of the GIS busbar model verified by simulation; Figure 4The local field strength distribution diagrams of the junction between the high-voltage conductor and the basin insulator are simulated and verified when there is no metal foreign matter and when different metal foreign matters are located; (a) is the local field strength distribution diagram of the junction between the high-voltage conductor and the basin insulator when there is no metal foreign matter, (b) is the local field strength distribution diagram of the junction between the high-voltage conductor and the basin insulator when the metal foreign matter is an aluminum block with a side length of 2mm, (c) is the local field strength distribution diagram of the junction between the high-voltage conductor and the basin insulator when the metal foreign matter is an iron ball with a diameter of 2mm, (d) is the local field strength distribution diagram of the junction between the high-voltage conductor and the basin insulator when the metal foreign matter is an aluminum wire with a length of 3mm and a diameter of 0.4mm, (e) (a) The local field strength distribution diagram of the junction between the high-voltage conductor and the basin-type insulator when the metal foreign body is an aluminum block with a side length of 1 mm, (b) The local field strength distribution diagram of the junction between the high-voltage conductor and the basin-type insulator when the metal foreign body is an iron ball with a diameter of 1 mm, (c) The local field strength distribution diagram of the junction between the high-voltage conductor and the basin-type insulator when the metal foreign body is an aluminum wire with a length of 6 mm and a diameter of 0.4 mm, (d) The local field strength distribution diagram of the junction between the high-voltage conductor and the basin-type insulator when the metal foreign body is an aluminum block with a side length of 0.5 mm, (e) The local field strength distribution diagram of the junction between the high-voltage conductor and the basin-type insulator when the metal foreign body is an iron ball with a diameter of 0.5 mm; Figure 5 The field strength distribution diagram along the surface of the basin insulator is simulated and verified when there is no metal foreign matter and when different metal foreign matters are placed on the surface of the basin insulator; (a) is the field strength distribution diagram along the surface of the basin insulator when there is no metal foreign matter, (b) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign matter is an aluminum block with a side length of 2mm, (c) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign matter is an iron ball with a diameter of 2mm, and (d) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign matter is an aluminum wire with a length of 3mm and a diameter of 0.4mm Figure, (e) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign body is an aluminum block with a side length of 1mm, (f) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign body is an iron ball with a diameter of 1mm, (g) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign body is an aluminum wire with a length of 6mm and a diameter of 0.4mm, (h) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign body is an aluminum block with a side length of 0.5mm, (i) is the field strength distribution diagram along the surface of the basin insulator when the metal foreign body is an iron ball with a diameter of 0.5mm; Figure 6 The local field strength distribution diagram of the basin insulator when there is no metal foreign matter and different metal foreign matters are placed in the air gap between the basin insulator and the grounding shell for simulation verification; (a) is the local field strength distribution diagram of the basin insulator when there is no metal foreign matter, (b) is the local field strength distribution diagram of the basin insulator when the metal foreign matter is an aluminum block with a side length of 2mm, (c) is the local field strength distribution diagram of the basin insulator when the metal foreign matter is an iron ball with a diameter of 2mm, and (d) is the local field strength distribution diagram of the basin insulator when the metal foreign matter is an aluminum wire with a length of 3mm and a diameter of 0.4mm; Figure 7 The local field strength distribution diagram of the grounding shell when there is no metal foreign matter and different metal foreign matters are placed in the air gap between the pot insulator and the grounding shell for simulation verification; (a) is the local field strength distribution diagram of the grounding shell when there is no metal foreign matter, (b) is the local field strength distribution diagram of the grounding shell when the metal foreign matter is an aluminum block with a side length of 2mm, (c) is the local field strength distribution diagram of the grounding shell when the metal foreign matter is an iron ball with a diameter of 2mm, and (d) is the local field strength distribution diagram of the grounding shell when the metal foreign matter is an aluminum wire with a length of 3mm and a diameter of 0.4mm; Figure 8 The field intensity distribution diagram on the surface of the basin insulator when different metal foreign bodies are placed in the wedge-shaped air gap of the ground electrode for simulation verification; (a) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an aluminum wire with a length of 3 mm and a diameter of 0.4 mm, (b) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an aluminum block with a side length of 1 mm, (c) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an iron ball with a diameter of 1 mm, (d) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an aluminum wire with a length of 6 mm and a diameter of 0.4 mm, (e) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an aluminum block with a side length of 0.5 mm, and (f) is the field intensity distribution diagram on the surface of the basin insulator when the metal foreign body is an iron ball with a diameter of 0.5 mm; Fig. 9 This is a comparison chart of field strength under different simulation scenarios for simulation verification.

[0016] Reference numerals 1. Grounded shell; 2. Air space; 3. Basin insulator; 4. High-voltage conductor. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not used to limit the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.

[0018] It should be noted that the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0019] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, a simulation analysis method for the harm of metal foreign matter to GIS equipment includes the following steps: S1. Use electromagnetic simulation software to establish a GIS busbar model; In step S1, the COMSOL multi-physics field simulation software is used to simulate and model the GIS busbar segment of the equal-size model for the 550 kV DC GIS scaled test to obtain a GIS busbar model, and the GIS busbar model includes a grounding shell 1, an air domain 2, a pot-type insulator 3 arranged in the middle position inside the grounding shell 1, and two high-voltage conductors 4 respectively arranged on both sides of the pot-type insulator 3; the air domain 2 is used to accommodate the gas insulating medium to provide insulation performance.

[0021] The material of the grounding outer side 1 is aluminum alloy, with a tangent thermal expansion coefficient of 21.4 / K and a density of 2700kg / m 3 ; The gas insulating medium is SF6 gas with a density of 26.08kg / m 3 , relative dielectric constant is 1.002; the material of pot-type insulator 3 is epoxy resin glue, and the density is 1673kg / m 3 , the relative dielectric constant is 4.

[0022] S2. Setting the simulation scene: determining the material, shape and location of the metal foreign body; The metal foreign body in step S2 is made of aluminum or iron, and is in the shape of a block, a line or a ball, and is disposed at the junction between the pot insulator and the high-voltage conductor, the surface of the pot insulator or the air gap between the pot insulator and the grounding shell. The metal foreign body is embedded in the surface of the pot insulator.

[0023] S3, perform electric field simulation: in each simulation scenario determined in step S2, run the simulation program, draw a field strength distribution diagram and a field strength comparison diagram under multiple operation scenarios; S4, based on the field intensity distribution diagram and field intensity comparison diagram drawn in step S3, finding the highest point of electric field intensity under metal foreign bodies of different materials, shapes and setting positions; S5. Determine the degree of damage caused by metal foreign matter to the GIS busbar model based on the highest point of the electric field intensity.

[0024] Simulation Verification In this simulation verification experiment, COMSOL Multiphysics 6.2 multi-physics simulation software was used for simulation software, A356.0 (ZL101A) was used for grounding shell, and Filled epoxy resin (X238) was used for basin insulator GIS modeling. Figure 2 The GIS busbar model shown in the figure and Figure 3 The electric field distribution is shown in FIG. 1 , and the metal foreign matter is shown in FIG. 1 .

[0025] Table 1 Types and sizes of metal foreign bodies

[0026] 1. Place various metal foreign bodies of various specifications shown in Table 1 at the junction between the high-voltage conductor and the spray basin insulator, and use no metal foreign body as a control. The results are as follows: Figure 4 shown.

[0027] Depend on Figure 4 It can be seen from Figures (b) and (c) that when an aluminum block with a side length of 2 mm and an iron ball with a diameter of 2 mm exist at the junction of the high-voltage conductor and the pot-type insulator, there is a peak field strength on the surface of the pot-type insulator and it appears at the junction of the metal foreign body, the pot-type insulator and SF6. At this time, the maximum field strength on the surface of the pot-type insulator increases to 0.8368 kV / mm and 1.3887 kV / mm, respectively, which is about 4 times and 6 times the maximum field strength of 0.2423 kV / mm when there is no metal foreign body.

[0028] Depend on Figure 4 It can be seen from Figures (e) and (f) that when the size of the aluminum block and the iron ball is reduced, the 1mm aluminum block causes two peaks in the field strength on the surface of the basin insulator, and between the two peaks, the field strength drops rapidly and approaches zero for a time. The 1mm iron ball causes a peak in the field strength on the surface of the basin insulator, and both are at the junction of the three media. At this time, the aluminum block with a side length of 1mm increases the maximum field strength on the surface of the basin insulator to 0.9583kV / mm, which is about 4.2 times the maximum field strength when there is no metal foreign matter, and is about 10% higher than the maximum field strength caused by the aluminum block with a side length of 2mm; the minimum field strength reaches 0.0082kV / mm. The iron ball with a diameter of 1mm increases the maximum field strength on the surface of the basin insulator to 1.2697kV / mm, which is about 5.2 times the maximum field strength when there is no metal foreign matter, and is about 10% lower than the maximum field strength caused by the iron ball with a diameter of 2mm.

[0029] Depend on Figure 4 It can be seen from Figures (h) and (i) that when the size of the aluminum block and the iron ball is further reduced to 0.5mm in both side length and diameter, the aluminum block also causes two peaks in the field strength on the surface of the basin insulator, with a minimum point between the two peaks, while the iron ball fluctuates slightly after reaching the peak. At this time, the maximum field strength on the surface of the basin insulator is 0.3104kV / mm and 0.3719kV / mm, respectively, which is about 30% and 50% higher than the maximum field strength on the surface when there is no metal foreign matter. In addition, the minimum field strength caused by the 0.5mm aluminum block is about 0.0084kV / mm.

[0030] Depend on Figure 4 It can be seen from Figures (d) and (g) that when aluminum wires with a diameter of 0.4 mm and lengths of 3 mm and 6 mm are placed at the junction of the pot insulator and the high-voltage conductor, the two cause two peaks in the maximum field strength on the surface of the pot insulator, and both are at the junction of three different media (metal foreign matter, pot insulator and SF6). Between the peaks, the aluminum wire also causes a relative minimum field strength. The minimum field strengths caused by the 3 mm aluminum wire and the 6 mm aluminum wire are 0.0274 kV / mm and 0.0902 kV / mm, respectively. At this time, the 3 mm aluminum wire can increase the maximum field strength on the surface of the pot insulator to 2.2743 kV / mm, which is about 10 times the maximum field strength on the surface of the pot insulator when there is no metal foreign matter. The 6 mm aluminum wire can increase the maximum field strength on the surface of the pot insulator to 4.8877 kV / mm, which is about 20 times the maximum field strength on the surface of the pot insulator when there is no metal foreign matter.

[0031] 2. Place metal foreign matter on the surface of the basin insulator and use a sample without metal foreign matter as a control. The results are as follows: Figure 5 shown.

[0032] Depend on Figure 5 It can be seen from Figures (b) and (c) that when an aluminum block with a side length of 2 mm is placed on the surface of the pot insulator, there are two peaks on the surface of the pot insulator, and there is a minimum point of field strength between the two peaks. When an iron ball with a diameter of 2 mm is placed, there is only one peak on the surface of the pot insulator, but before the surface field strength reaches the peak, it will decrease to a certain extent and lead to a minimum value of the field strength. Among them, the maximum field strength appears at the junction of the three different media (metal foreign matter, pot insulator and SF6) closer to the b end (relatively closer to the high-voltage conductor). At this time, the 2mm aluminum block increases the maximum surface field strength of the basin insulator to 0.8244kV / mm, which is about 4 times the maximum surface field strength when there is no metal foreign matter, and the minimum field strength is 0.0042kV / mm; the 2mm iron ball increases the maximum surface field strength of the basin insulator to 1.0313kV / mm, which is about 6 times the maximum surface field strength when there is no metal foreign matter, and the minimum value is 0.051kV / mm.

[0033] Depend on Figure 5It can be seen from Figures (e) and (f) that when the size of the aluminum block and the iron ball is reduced to 1mm, the change trend of the field strength on the surface of the basin insulator is similar to that of the aluminum block and the iron ball with a size of 2mm. The aluminum block with a side length of 1mm increases the maximum field strength on the surface of the basin insulator to 0.7724kV / mm, which is about 3 times the maximum field strength when there is no metal foreign matter, and 10% lower than the maximum field strength caused by the aluminum block with a side length of 2mm. The minimum field strength reaches 0.0021kV / mm. The iron ball with a diameter of 1mm increases the maximum field strength on the surface of the basin insulator to 1.2552kV / mm, which is about 5 times the maximum field strength when there is no metal foreign matter, and 10% higher than the maximum field strength caused by the iron ball with a diameter of 2mm. The minimum field strength is 0.0275kV / mm.

[0034] Depend on Figure 5 It can be seen from Figure (h) and Figure (i) that when the size of the aluminum block and the iron ball is reduced to 0.5mm, the two will cause the field strength on the surface of the basin insulator to have two peaks and a minimum point. The minimum point is between the two peaks, and the maximum field strength still appears at the junction of three different media (metal foreign matter, basin insulator and SF6). At this time, the maximum field strength caused by the aluminum block with a side length of 0.5mm is 0.5888kV / mm, which is 2.3 times the maximum field strength when there is no metal foreign matter, and the minimum value is 0.0095kV / mm. The maximum field strength caused by the iron ball with a diameter of 0.5mm is 0.6931, which is 2.7 times the maximum field strength when there is no metal foreign matter, and the minimum value is 0.0084kV / mm.

[0035] Depend on Figure 5 Figures (d) and (g) show that after placing aluminum wires with a diameter of 0.4 mm, a length of 3 mm and a length of 6 mm on the surface of the pot insulator, they will also cause two field intensity peaks and a field intensity minimum. The maximum field intensity appears at the junction of the three media (metal foreign matter, pot insulator and SF6). The aluminum wire with a length of 3 mm increases the maximum field intensity on the surface of the pot insulator to 3.5890 kV / mm, and the aluminum wire with a length of 6 mm increases the maximum field intensity on the surface of the pot insulator to 4.8001 kV / mm, which are 14 and 19 times the maximum field intensity when there is no metal foreign matter, respectively. In addition, the minimum field intensity caused by the two is 0.0091 kV / mm and 0.0057 kV / mm, respectively.

[0036] 3. Place metal foreign matter in the air gap between the basin insulator and the grounding shell, and use a control group without metal foreign matter. The results are as follows: Figure 6-Figure 7 shown.

[0037] Depend on Figure 6 It can be seen that the 2mm aluminum block, 2mm iron ball and 3mm aluminum wire increase the maximum field strength on the surface of the basin insulator to about 3 times, 24 times and 8 times when there is no metal foreign matter. Figure 7It can be seen that the aluminum block with a side length of 2mm and the aluminum wire with a length of 3mm increase the maximum electric field strength on the surface of the grounded shell to 10.5 times and 16.8 times respectively when there is no metal foreign matter, and the iron ball with a diameter of 2mm increases the maximum electric field strength on the surface of the grounded shell to 3.7 times when there is no metal foreign matter.

[0038] When the metal foreign body falls into the wedge-shaped air gap of the ground electrode with a width of about 1.7 mm, each metal foreign body is about 110 mm away from the high-voltage conductor, and the results are as follows Figure 8 shown.

[0039] Depend on Figure 8 As shown in Figures (b) and (c), after the aluminum block with a side length of 1 mm falls into the bottom of the air gap, the maximum field strength on the surface of the basin insulator is 0.1838 kV / mm, which is close to that when there is no metal foreign matter. The iron ball with a diameter of 1 mm increases the maximum field strength on the surface to 0.2644 kV / mm, which is about 40% higher than when there is no metal foreign matter.

[0040] Depend on Figure 8 It can be seen from Figures (e) and (f) that when the 0.5 mm aluminum block and iron ball fall into the bottom of the air gap, the maximum surface field strength of the basin insulator is 0.1827 kV / mm and 0.1920 kV / mm, respectively, which is close to the maximum surface field strength when there is no metal foreign matter.

[0041] Depend on Figure 8 As shown in Figures (a) and (d), when an aluminum wire with a diameter of 0.4 mm and a length of 3 mm falls into the bottom of the air gap, the maximum field strength on the surface of the basin insulator reaches 0.5151 kV / mm, which is about 2.7 times that when there is no metal foreign matter. When an aluminum wire with a diameter of 0.4 mm and a length of 6 mm falls into the bottom of the air gap, the maximum field strength on the surface of the basin insulator is 0.1725 kV / mm, which is close to the maximum field strength when there is no metal foreign matter.

[0042] At the same time, different simulation scenarios are obtained. Fig. 9 The field strength distribution diagram shown is given by Fig. 9It can be seen that, due to being closest to the high-voltage conductor, under the premise of uniform shape and size of the metal foreign matter, the metal foreign matter at the junction between the high-voltage conductor and the basin insulator causes the highest degree of electric field distortion; among the metal foreign matter at the same position and the same shape, the larger the size and surface area, the stronger the electric field concentration, the larger the impact range, and the stronger the field strength distortion caused; when placing metal foreign matter at the junction of the high-voltage conductor and the basin insulator and in the middle of the basin insulator, since the electric field will be concentrated at the tip and edge of the foreign matter, the linear metal foreign matter has a larger surface area and a sharper shape, resulting in the largest field strength distortion of the metal foreign matter, which is 6mm in length and 0.4mm in diameter, followed by 3mm in length and 0.4mm in diameter. The shape of the iron ball is relatively uniform, and the shape of the aluminum block is the flattest, so the field strength distortion caused by the two is relatively weak; and in the wedge-shaped air gap between the ground electrode, the surface area of ​​the aluminum wire in contact with the basin insulator becomes smaller, resulting in a smaller field strength distortion caused by it, and the electric field concentration at the contact point between the iron ball and the basin insulator is the strongest. Therefore, the field strength distortion caused by the iron ball is the largest, followed by the aluminum wire, and the aluminum block is the smallest.

[0043] In summary, linear metal foreign bodies are the most common type at GIS sites. Simulation studies have shown that the electric field distortion effect caused by such foreign bodies is extremely serious. The electric field distortion caused by such foreign bodies, whether close to high-voltage conductors or in the middle of pot-type insulators, will be more than 10 times that without metal foreign bodies, and the larger the size of the foreign bodies, the more serious the impact. If these long strips of metal foreign bodies are attached to the surface of pot-type insulators, they will cause high-intensity electric field distortion, which may cause surface flashover of pot-type insulators, accelerate the aging of insulating materials and damage equipment, thus seriously threatening the safe and stable operation of GIS equipment.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A simulation analysis method for the harm of metal foreign matter to GIS equipment, characterized by: The following steps are involved: S1. Use electromagnetic simulation software to establish a GIS busbar model; S2. Setting the simulation scene: determining the material, shape and location of the metal foreign body; S3, perform electric field simulation: in each simulation scenario determined in step S2, run the simulation program, draw a field strength distribution diagram and a field strength comparison diagram under multiple operation scenarios; S4, based on the field intensity distribution diagram and field intensity comparison diagram drawn in step S3, finding the highest point of the electric field intensity under different materials, shapes and setting positions; S5. Determine the degree of damage caused by metal foreign matter to the GIS busbar model based on the highest point of the electric field intensity.

2. The method for simulating and analyzing the damage of metal foreign matter to GIS equipment according to claim 1 is characterized in that: In step S1, the GIS busbar segment of the equal-size model for the 550 kV DC GIS scaled test is simulated and modeled by using COMSOL multi-physics field simulation software to obtain a GIS busbar model, and the GIS busbar model includes a grounding shell, an air domain, a pot-type insulator arranged at the middle position inside the grounding shell, and two high-voltage conductors respectively arranged on both sides of the pot-type insulator; The air space is used to contain the gas insulation medium and provide insulation performance.

3. The method for simulating and analyzing the harm of metal foreign matter to GIS equipment according to claim 2 is characterized in that: The material of the outer side of the ground is aluminum alloy, with a tangent thermal expansion coefficient of 21.4 / K and a density of 2700kg / m 3 ; The gas insulation medium is SF6 gas with a density of 26.08kg / m 3 , the relative dielectric constant is 1.002; The material of the pot insulator is epoxy resin glue, with a density of 1673kg / m 3 , the relative dielectric constant is 4.

4. The method for simulating and analyzing the damage of metal foreign matter to GIS equipment according to claim 3 is characterized in that: The metal foreign body described in step S2 is made of aluminum or iron, and is in the shape of a block, a line or a sphere. It is disposed at the junction between the pot insulator and the high-voltage conductor, the surface of the pot insulator or the air gap between the pot insulator and the grounding shell.

5. The method for simulating and analyzing the harm of metal foreign matter to GIS equipment according to claim 4 is characterized in that: Metal foreign matter is embedded in the surface of the pot insulator.

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