A Design and Preparation Method of a High-Performance Dielectric Layered Insulator

Abstract

The present invention discloses a design and preparation method for a high-performance dielectric layered insulator. By designing the relative dielectric constants of each layer of the dielectric layered insulator, selecting different types of filler particles, and taking advantage of the differences in the sedimentation rates of different fillers in liquid epoxy resin, different composite material layers are finally formed relying on the gravity and buoyancy forces acting on the fillers. The results show that, compared with traditional homogeneous insulators, the high-performance dielectric layered insulator achieves a uniform tangential electric field distribution along the surface of the homogeneous insulator, and at the same time, this insulator has the ability to actively drive away metal particles, effectively suppressing the discharge damage caused by metal particles. The present invention can efficiently prepare high-performance dielectric layered insulators, prevent the occurrence of insulation failure accidents, and improve the reliability and stability of high-voltage electrical equipment.

Description

Technical Field

[0001] The present invention relates to the field of preparation of modified insulating polymeric materials in the field of high-voltage equipment manufacturing, and more specifically, to a design and preparation method of a high-performance dielectric layered insulator. Background Art

[0002] Gas Insulated Switchgear has significant advantages such as small floor area, high operating reliability, strong stability, strong anti-pollution ability, long maintenance cycle, and no electromagnetic environment effect, and has been widely used in power transmission and transformation projects of various voltage levels at home and abroad, urban distributed power systems and other fields. Epoxy resin cast insulators, as key insulating components in GIS equipment, are built into the GIS shell and play roles such as mechanical support, electrical insulation, and unit isolation, which is of great significance for maintaining the safe and stable operation of the entire GIS. The main reason for the low creeping flashover inception voltage of the insulator is that the electrical parameters of the insulating material do not match those of the insulating gas, resulting in local electric field intensity concentration at the triple junction of the insulator, metal electrode, and gas, and the electrical withstand performance of the insulator is reduced. At the same time, during the production, assembly, and operation of GIS, metal particle pollutants will inevitably be generated due to factors such as vibration and friction. The metal particles exacerbate the electric field distortion of GIS, causing a significant decrease in the insulation strength of sulfur hexafluoride (SF6) gas, which is an important hidden danger threatening the safety of GIS projects. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art that although the dielectric layer-by-layer construction of the insulator can be realized by 3D printing technology, it faces poor mechanical properties, low preparation efficiency, poor dielectric constant distribution effect, and is difficult to be put into practical application; the process of preparing dielectric layer-by-layer insulators by the method of pouring layer by layer is complex and inefficient. The present invention provides a new design and preparation method of a high-performance dielectric layer-by-layer insulator. The present invention provides a brand-new idea for the preparation of AC GIS dielectric layer-by-layer insulators.

[0004] The present invention applies the concept of dielectric layer-by-layer materials in the field of materials science to the field of electrical insulation, and regulates the electric field distribution on the surface and near the insulator under AC voltage by constructing an insulating structure with a layered relative dielectric constant. By adding various filler particles into the epoxy resin matrix, the dielectric constants, densities, and sizes of the filler particles are all different, and a multi-layer dielectric constant layer structure is formed under the action of its own gravity, so as to achieve the purpose of uniforming the electric field on the surface of the insulator, improving the electric field near the insulator, suppressing local electric field distortion, and increasing the creeping flashover inception voltage of the insulator.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A new design and preparation method of a high-performance dielectric layer-by-layer insulator, comprising the following steps:

[0006] Step 1: Divide the insulator into several layers and determine the relative permittivity of each layer of the insulator;

[0007] Step 2: Select the type of filler and calculate the volume fraction of the filler according to the relative permittivity of each layer determined in Step 1;

[0008] Step 3: Calculate the volume of each layer of the high-performance dielectric layered insulator;

[0009] Step 4: Calculate the doping mass of the filler particles in each layer according to the relative permittivity of each layer determined in Step 1 and the volume of each layer calculated in Step 3;

[0010] Step 5: Calculate the required mass of the epoxy resin matrix;

[0011] Step 6: Mix the filler amount calculated in Step 4 with the epoxy resin matrix with the mass number calculated in Step 5 and stir well in a vacuum mixer to obtain a mixed solution;

[0012] Step 7: Pour the mixed solution in Step 6 into the insulator mold through a vacuum casting device;

[0013] Step 8: Seal the mold in Step 7 and place it horizontally on a constant temperature vibration platform;

[0014] Step 9: Place the vibrated mold in Step 8 in an oven for curing and forming;

[0015] Step 10: Take out the formed high-performance dielectric layered insulator from the mold, process the surface defects to form the final high-performance dielectric layered insulator;

[0016] The relative permittivity of each layer in Step 1 is denoted as: ε1, ε2,..., ε n ; Step 1 is divided into 3, 5, 7 or 9 layers;

[0017] Three different filler particles are selected in Step 2, and their parameters include filler particle size, density, and relative permittivity; the volume fraction of the filler in each layer is denoted as V t1 , V t2 ,..., V tn ;

[0018] The volume of each layer of the high-performance dielectric layered insulator in Step 3 is denoted as V1, V2,..., V n ;

[0019] The doping mass of the filler particles in each layer in Step 4 is denoted as m1, m2,..., m n ;

[0020] The mass of the epoxy resin in Step 5 is denoted as m EP .

[0021] Further, the calculation formula for the filler volume fraction in the second step is as follows:

[0022] 1) When the relative permittivity of the filler is greater than that of the epoxy resin:

[0023]

[0024] 2) When the relative permittivity of the filler is less than that of the epoxy resin:

[0025]

[0026] In the formula: V ti is the volume fraction of the i-th layer of filler, ε ti is the relative permittivity of the i-th layer of filler; ε EP is the relative permittivity of the epoxy resin; i = 1, 2, 3, …, n.

[0027] Further, the total volume of the insulator in the third step is denoted as V all and the total volume of the insulator V all is the sum of the volumes V i occupied by each layer of the insulator.

[0028] Further, the calculation formula for the doping mass of each layer of filler in the fourth step is:

[0029] m i = V ti ·V i ·ρ i

[0030] In the formula: m i is the mass of the i-th layer of filler; V ti is the volume fraction of the i-th layer of filler; V i is the volume of the i-th layer; ρ i is the density of the i-th layer of filler; i is the number of dielectric layers of the insulator, i = 1, 2, …, n.

[0031] Further, the calculation formula for the total mass m EP of the epoxy resin required in the fifth step is:

[0032]

[0033] In the formula: V i is the volume of the i-th layer; V ti is the volume fraction of the i-th layer of filler; ρ EP is the density of the epoxy resin; i is the number of dielectric layers of the insulator i = 1, 2, 3, …, n.

[0034] Further, in the sixth step, the stirring time in the vacuum mixer is 2 ± 1 h, the rotation speed is 60 ± 10 r / s, and the temperature is 120 ± 20 °C.

[0035] Further, in the eighth step, the vibration frequency of the constant temperature vibration table is 120 ± 10 Hz, the temperature is 120 ± 10 °C, and the vibration time is 1 ± 0.5 h.

[0036] Further, in the ninth step, the oven temperature is 130 ± 20 °C, and the curing time is 24 ± 5 h.

[0037] Compared with the prior art, the beneficial effects brought by the present invention are as follows:

[0038] 1. The composite insulating material prepared by the preparation method of the present invention has a simpler process and lower production cost compared with the insulating materials produced by 3D printing and layer-by-layer curing technologies.

[0039] 2. The high-performance dielectric layer-insulated insulator prepared by the present invention can adjust the electric field through the gradient-distributed dielectric properties compared with the conventional insulator with a uniform dielectric constant distribution, evenly distribute the electric field on the surface of the insulator, inhibit the enhancement of the local electric field, and thus prevent the surface discharge of the insulator, improving the vacuum surface flashover voltage and the surface withstand voltage level of the insulator.

[0040] 3. The high-performance dielectric layer-insulated insulator prepared by the present invention can adjust the axial electric field near the insulator compared with the conventional insulator with a uniform dielectric constant distribution, hinder the movement of metal particles towards the insulator, and inhibit the discharge damage caused by metal particles.

[0041] 4. The dielectric layer-insulated insulator prepared by the present invention is integrally formed and has high mechanical strength. Therefore, the product has high stability and strong consistency, and can achieve mass production after a fixed process, with great engineering value.

[0042] 5. The present invention selects different filler particles according to engineering needs to meet the required dielectric constant distribution characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic structural diagram of a high-performance dielectric layer-insulated insulator;

[0044] Figure 2 It is the preparation process of a high-performance dielectric layer-insulated insulator;

[0045] Figure 3 It is a physical diagram of a 110 kV high-performance dielectric layer-insulated insulator;

[0046] Figure 4 It is a comparison diagram of the surface electric field distribution between a high-performance dielectric layer-insulated insulator and a traditional uniform insulator;

[0047] Figure 5 The movement trajectory of spherical metal particles placed 25 mm away from the high-performance dielectric stratified insulator and the traditional uniform insulator. Specific implementation mode

[0048] The following further illustrates how the present invention is implemented in conjunction with the attached drawings and specific embodiments.

[0049] The present invention takes the preparation of 110 kV high-performance pot insulators as an example, but is not limited to insulators of the 110 kV voltage level. As Figure 1 shown, a high-performance dielectric stratified insulator includes three gradient layers, namely EP / BaTiO3 layer 1, EP / Al2O3 layer 2, and EP / H-SiO2 layer.

[0050] As Figure 2 shown, the steps of a method for preparing a high-performance insulator are as follows:

[0051] Step 1: Taking a 110 kV AC pot insulator as an example, determine that the required number of insulator gradient layers is 3, and determine the relative dielectric gradient range to be 1.9 - 9.6. Specifically, the relative dielectric constant of layer 01 is 9.6, the relative dielectric constant of layer 02 is 5.5, and the relative dielectric constant of layer 03 is 1.9.

[0052] Step 2: According to the relative dielectric constants of each layer determined in Step 1, select 3 types of filler particles, namely: barium titanate (BaTiO3) particles, with an average diameter of 20 μm, relative dielectric constant (ε t1 ) 1600, density 6 kg / m 3 ; alumina (Al2O3) particles, with an average diameter of 10 μm, relative dielectric constant (ε t2 ) 9.0, density 3.5 kg / m 3 ; hollow silica (H-SiO2) particles, with an average diameter of 100 μm, relative dielectric constant (ε t3 ) 1.1, density 0.3 kg / m 3 ;

[0053] Calculate the volume fraction of each layer of filler according to the following formula:

[0054] 1) When the relative dielectric constant of the filler is greater than the relative dielectric constant of the epoxy resin:

[0055]

[0056] 2) When the relative dielectric constant of the filler is less than the relative dielectric constant of the epoxy resin:

[0057]

[0058] In the formula: V tiis the volume fraction of the filler in the i-th layer, ε ti is the relative permittivity of the filler in the i-th layer; ε EP is the relative permittivity of epoxy resin, 4.25; i = 1, 2, 3.

[0059] The volume fraction V of BaTiO3 filler in the 01 layer t1 is 43.3%; The volume fraction V of Al2O3 filler in the 02 layer t2 is 47.2%; The volume fraction V of H-SiO2 filler in the 03 layer t3 is 45.4%.

[0060] Step 3: The total volume V of the 110 kV pot insulator all is 2.5 L. Calculate the volume occupied by each layer of the high-performance dielectric graded insulator. The volume V1 of EP / BaTiO3 in the 01 layer is 0.54 L, the volume V2 of EP / Al2O3 in the 02 layer is 0.86 L, and the volume V3 of EP / H-SiO2 in the 03 layer is 1.1 L;

[0061] Step 4: According to the relative permittivity of each layer determined in Step 1 and the volume of each layer calculated in Step 3, calculate the doped mass of the filler particles in each layer. The calculation formula is as follows:

[0062] m i = V ti ·V i ·ρ i

[0063] In the formula: m i is the mass of the filler in the i-th layer; V ti is the volume fraction of the filler in the i-th layer; V i is the volume of the i-th layer; ρ i is the density of the filler in the i-th layer; i is the number of dielectric grading layers of the insulator, i = 1, 2, 3.

[0064] The mass m1 of BaTiO3 filler in the 01 layer is 1.403 kg; The mass m2 of Al2O3 filler in the 02 layer is 1.421 kg; The mass m3 of H-SiO2 filler in the 03 layer is 0.150 kg.

[0065] Step 5: Calculate the required mass m of epoxy resin EP , and the calculation formula is:

[0066]

[0067] In the formula: V i is the volume of the i-th layer; V ti is the volume fraction of the filler in the i-th layer; ρ EP is the density of epoxy resin, 3.5 kg / m 3 ; i is the number of dielectric grading layers of the insulator, i = 1, 2, 3.

[0068] Total mass of epoxy resin m EP It is 1.705kg.

[0069] Step 6: Mix the filler in step 4 with the epoxy resin matrix in step 5, and stir them thoroughly in a vacuum mixer for 2 hours at a speed of 60 r / s and a temperature of 120° C.;

[0070] Step 7: Pour the mixed liquid in step 6 into the insulator metal mold through vacuum casting equipment;

[0071] Step 8: Seal the mold in step 7 and place it horizontally on a constant temperature vibration platform with a vibration frequency of 120 Hz, a temperature of 120°C, and a vibration time of 1 hour;

[0072] Step 9: Place the vibrated mold in step 8 in an oven at 130°C for 24 hours.

[0073] Step 10: Take the formed high-performance dielectric layered insulator out of the mold, process the surface defects, and form the final high-performance dielectric layered insulation (such as Figure 3 shown).

[0074] like Figure 4 As shown, the maximum tangential electric field along the concave surface of the traditional uniform insulator is 5.61kV / mm, while the maximum electric field of the high-performance dielectric layered insulator is 4.39kV / mm, and the maximum tangential non-uniformity coefficient along the surface is reduced by 22%; the maximum tangential electric field on the convex surface of the traditional uniform insulator is 4.36kV / mm, while that of the high-performance dielectric layered insulator is 3.30kV / mm, and the maximum tangential non-uniformity coefficient along the surface is reduced by 25%, proving that high-performance dielectric layered insulators can significantly improve the uniformity of the tangential electric field distribution along the surface of the insulator.

[0075] like Figure 5 As shown in the figure, the movement trajectory of the metal particles is marked by the dotted line. The metal particles released at a distance of 25 mm from the traditional uniform insulator jump on the shell surface and move toward the insulator. The metal particles released at a distance of 25 mm from the high-performance dielectric layered insulator jump away from the insulator and eventually jump out of the model boundary. It is proved that the high-performance dielectric layered insulator can actively drive the metal particles away from the insulator surface and effectively suppress the discharge damage caused by the metal particles.

Claims

1. A design and preparation method of a high-performance dielectric layered insulator, characterized in that, By constructing an insulating structure with a stratified relative permittivity, the electric field distribution on and near the surface of the insulator under AC voltage is regulated. By incorporating different filler particles into the epoxy resin matrix, the filler particles have different permittivities, densities, and sizes, and form a multi-layer permittivity layer structure under the action of their own gravity, so as to achieve uniform electric field on the insulator surface and improve the electric field near the insulator; It includes the following steps: Step 1: Divide the insulator into several layers and determine the relative permittivity of each layer of the insulator; Step 2: According to the relative permittivity of each layer determined in Step 1, select the type of filler and calculate the filler volume fraction; Step 3: Calculate the volume occupied by each layer of the high-performance dielectric stratified insulator; Step 4: According to the relative permittivity of each layer determined in Step 1 and the volume occupied by each layer calculated in Step 3, calculate the doping mass of the filler particles in each layer; Step 5: Calculate the required mass of the epoxy resin matrix; Step 6: Mix the filler amount calculated in Step 4 with the epoxy resin matrix with the mass number calculated in Step 5 and stir well in a vacuum mixer to obtain a mixed solution; Step 7: Pour the mixed solution in Step 6 into the insulator mold through a vacuum casting device; Step 8: Seal the mold in Step 7 and place it horizontally on a constant temperature vibration platform; Step 9: Place the vibrated mold in Step 8 in an oven for curing and forming; Step 10: Take out the formed high-performance dielectric stratified insulator from the mold, process the surface defects to form the final high-performance dielectric stratified insulator; The relative permittivities of each layer in the first step are respectively denoted as: ε1, ε2, …, ε n ; In the second step, three different filler particles are selected, and their parameters include filler particle size, density, and relative dielectric constant; the volume fractions of each layer of filler are respectively denoted as V t1 , V t2 , …, V tn ; In step 3, the volumes of each layer of the high-performance dielectric layered insulator are respectively denoted as V1, V2, …, V n ; The doped masses of the filler particles in each layer in the fourth step are respectively denoted as m1, m2, …, m n ; The mass of the epoxy resin in step five is denoted as m EP ; The calculation formula for the filler volume fraction in Step 2 is as follows: 1) When the relative permittivity of the filler is greater than the relative permittivity of the epoxy resin: 2) When the relative permittivity of the filler is less than the relative permittivity of the epoxy resin: Where: V ti is the volume fraction of the packing in the i-th layer, and ε ti is the relative permittivity of the packing in the i-th layer; ε EP is the relative permittivity of the epoxy resin; i = 1, 2, 3, …, n.

2. The design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that, In step 3, the total volume of the insulator is denoted as V all and the total volume V of the insulator all is the sum of the volumes V i occupied by each layer of the insulator; The calculation formula for the doping mass of the filler in each layer in Step 4 is: m i = V ti ·V i ·ρ i Where: m i is the mass of the packing material in the i-th layer; V ti is the volume fraction of the packing material in the i-th layer; V i is the volume of the i-th layer; ρ i is the density of the packing material in the i-th layer; i is the number of dielectric layers of the insulator, i = 1, 2, …, n.

3. A design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that, The total mass m of epoxy resin required in the fifth step EP The calculation formula is as follows: Where: V i is the volume of the i-th layer; V ti is the volume fraction of the packing material in the i-th layer; ρ EP is the density of epoxy resin; i is the number of dielectric layers of the insulator, i = 1, 2, 3, …, n.

4. A design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that, In Step 6, the stirring time in the vacuum mixer is 2 ± 1 h, the rotation speed is 60 ± 10 r / s, and the temperature is 120 ± 20 °C.

5. A design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that In Step 8, the vibration frequency of the constant temperature vibration table is 120 ± 10 Hz, the temperature is 120 ± 10 °C, and the vibration time is 1 ± 0.5 h.

6. The design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that, In Step 9, the oven temperature is 130 ± 20 °C, and the curing time is 24 ± 5 h.

7. A design and preparation method of a high-performance dielectric layered insulator according to claim 1, characterized in that In Step 1, it is divided into 3, 5, 7 or 9 layers.

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