CN111331767A - Method for manufacturing surface conductance nonlinear insulator by centrifugal technology - Google Patents

Abstract

The invention discloses a method for manufacturing surface conductance nonlinear insulators by centrifugal technology, which comprises the following steps: 1) mold preparation; 2) centrifuge preparation; 3) casting material preparation: under the vacuum condition of 130 DEG C, an epoxy resin matrix ( Model CT-5531) and curing agent (model HY-5533) were mixed in a ratio of 100:85, and then α-type silicon carbide particles were added, and stored in a vacuum and 130 ℃ environment for later use; 4) Two-step casting method: to After adding the accelerator to the castable in step 3), the casting work is carried out quickly, so that the castable just fills the entire mold, and the mold is sealed with a lid to prevent the castable from leaking during the centrifugation process. The body and the surface nonlinear silicon carbide layer of the surface conductive nonlinear pillar insulator prepared by the centrifugal method are integrally solidified and formed, so they have excellent interface stability and can effectively control the electric field distribution.

Description

A method for fabricating surface conductance nonlinear insulators by centrifugal technology

technical field

The invention belongs to the technical field of insulator preparation, and in particular relates to a method for manufacturing surface conductance nonlinear insulators by centrifugal technology.

Background technique

HVDC pipeline transmission has many advantages, such as large transmission capacity, high reliability and small footprint. The creepage flashover of pillar insulators is a common fault form and limiting factor of DC GIL (Gas Insulated Lines). Therefore, trying to improve the creepage flashover voltage of the DC GIL pillar insulator is of great significance for improving the working reliability of the GIL and further reducing the size of the pipeline. The surface conductance nonlinear insulator not only has good surface electric field regulation function, but also has small conductance loss, and has broad application prospects in DC GIL. The invention utilizes the centrifugal method to manufacture the surface conductivity nonlinear insulator, realizes the integral solidification molding of the insulator matrix and the surface nonlinear layer, and has excellent interface bonding ability.

SUMMARY OF THE INVENTION

The invention takes a simplified circular truncated pillar insulator as a prototype, and aims to provide a technology for manufacturing a surface conductance nonlinear insulator by a centrifugal method, thereby improving the working reliability of the DC GIL insulator and further reducing the size of the GIL pipeline.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for manufacturing surface conductance nonlinear insulators by centrifugal technology, comprising the following steps:

1) Mold preparation

The mold used in the present invention is shown in Figure 1, and its key features are: first, a rotationally symmetric structure; second, the mold gate is on the top, and is equipped with a cover with a sealing function.

2) Centrifuge preparation

The structure of the centrifuge used in the present invention is shown in Figure 2, and its key features are: first, it has a rotating platform with adjustable speed, which is used to provide the required centrifugal force; Curing provides temperature conditions.

3) Castable preparation

The epoxy resin matrix (type CT-5531) and the curing agent (type HY-5533) were mixed in a ratio of 100:85 under vacuum conditions at 130 °C, and then an appropriate proportion of α-type silicon carbide particles was added as needed, and stored in Standby in vacuum and 130°C environment.

4) Two-step casting method

After adding the accelerator to the castable in step 3), the casting work is carried out quickly, so that the castable just fills the entire mold, and the mold is sealed with a lid to prevent the castable from leaking during the centrifugation process.

Step 1: Use short-term high-speed centrifugation. At this time, the centrifugal force on the mold surface is much larger than (gravity + viscous force), and the silicon carbide particles move up along the mold surface and gather on the top of the mold.

The second part: using long-time low-speed centrifugation, at this time (centrifugal force + viscous force) on the surface of the mold is less than gravity, the silicon carbide particles gathered on the top of the mold slide along the surface of the mold during the curing process of the epoxy resin, and finally form A silicon carbide layer of uniform thickness is shown in Figure 3.

beneficial effect

The body and the surface nonlinear silicon carbide layer of the surface-conductivity nonlinear post insulator prepared by the centrifugal method are integrally solidified and formed, so they have excellent interface stability.

The surface conductance nonlinear insulator prepared by centrifugal method can effectively control the electric field distribution, as shown in Figure 4.

Description of drawings

Figure 1 shows the schematic diagram of the mold (a) and the physical map (b).

Figure 2 shows a schematic diagram of the structure of the centrifuge.

Figure 3 shows the schematic diagram of the two-step centrifugation method (a) and the cross-sectional photo of the surface nonlinear insulator (b).

Figure 4 shows the electric field distribution of the insulators: (a) traditional pillar insulator, (b) surface conductance nonlinear insulator.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

The best embodiment of manufacturing surface conductance nonlinear strut insulators by centrifugal method is as follows:

1. The optimal formula (mass ratio) of the castable is as follows: epoxy resin matrix (model CT-5531): curing agent (model HY-5533): accelerator: silicon carbide (α type 20μm) = 100:85:0.2 :15. The higher the silicon carbide content, the greater the thickness of the surface nonlinear layer. The thickness of the nonlinear surface layer of the surface conductance nonlinear insulator poured according to the optimal formula is about 0.1 mm, the thickness is uniform and the process is easy to control.

2. If different formulas are used, the centrifugal speed and time need to be adjusted appropriately according to the viscosity of the epoxy resin and the density and particle size of the filler. The higher the epoxy viscosity, the smaller the filler density and particle size, the higher the centrifugal speed and the longer the time required.

A method for manufacturing a surface conductance nonlinear insulator by centrifugal technology, comprising the following steps:

1) Mold preparation

The mold used in the present invention is shown in Figure 1, and its key features are: first, a rotationally symmetric structure; second, the mold gate is on the top, and is equipped with a cover with a sealing function.

2) Centrifuge preparation

The structure of the centrifuge used in the present invention is shown in Figure 2, and its key features are: first, it has a rotating platform with adjustable speed, which is used to provide the required centrifugal force; Curing provides temperature conditions.

3) Castable preparation

The epoxy resin matrix (type CT-5531) and the curing agent (type HY-5533) were mixed in a ratio of 100:85 under vacuum conditions at 130 °C, and then an appropriate proportion of α-type silicon carbide particles was added as needed, and stored in Standby in vacuum and 130°C environment.

4) Two-step casting method

After adding a small amount of accelerator to the castable in step 3, the pouring work is carried out quickly, so that the castable just fills the entire mold, and the mold is sealed with a lid to prevent the castable from leaking during the centrifugation process.

Step 1: Use short-term high-speed centrifugation. At this time, the component of centrifugal force on the mold surface is much larger than the combined force of gravity and viscous force, and the silicon carbide particles move upward along the mold surface and gather on the top of the mold.

The second part: using long-time low-speed centrifugation, at this time, the combined force of centrifugal force and viscous force on the mold surface is less than gravity, and the silicon carbide particles gathered on the top of the mold slide along the surface of the mold during the curing process of the epoxy resin, and finally form A silicon carbide layer of uniform thickness is shown in Figure 3.

The best embodiment of the centrifugation process of the optimal formula of the present invention is as follows: (1) under the environment of 130°C, the rotation speed of the centrifuge is 1400 r/min, and the time is 2 minutes; (2) under the environment of 130°C, the rotation speed of the centrifuge is 140 r/min, and the time 30min. Finally, the mold was put into an oven with a temperature of 130 °C for 2 hours of secondary curing.

Claims (4)

1. A method for manufacturing a surface conductance nonlinear insulator by a centrifugal technology is characterized by comprising the following steps:

1) preparing a mould: the requirement is met by a rotational symmetric structure, a mold gate is arranged at the top, and a cover with a sealing function is arranged;

2) preparing a centrifuge: the requirement is satisfied that the rotary platform has adjustable speed and is used for providing required centrifugal force;

the device is provided with a temperature-adjustable thermostat which provides temperature conditions for the solidification of the insulator;

3) preparing a casting material:

mixing an epoxy resin matrix and a curing agent according to the proportion of 100:85 at the temperature of 130 ℃ under vacuum, adding α type silicon carbide particles, and storing in a vacuum environment at the temperature of 130 ℃ for later use;

4) the two-step casting method comprises the following steps: adding an accelerant into the pouring material obtained in the step 3), and then quickly pouring, so that the pouring material just fills the whole mould, and sealing the mould by using a cover to prevent the pouring material from leaking in the centrifugal process;

(1) the short-time high-speed centrifugation is adopted, the component of the centrifugal force on the surface of the mold is far larger than the resultant force of gravity and viscous force, and silicon carbide particles move upwards along the surface of the mold and gather at the top of the mold;

(2) adopting long-time low-speed centrifugation, wherein the component of the resultant force of the centrifugal force and the viscous force on the surface of the mold is smaller than the gravity, and the silicon carbide particles gathered on the top of the mold slide down along the surface of the mold in the curing process of the epoxy resin;

(3) finally, a silicon carbide layer with uniform thickness is formed.

2. The method for manufacturing surface conduction nonlinear insulator by centrifugal technology according to claim 1, wherein the technical parameters in step 4) (1) are as follows: the rotating speed of the centrifuge is 1400r/min under the environment of 130 ℃, and the time is 2 min.

3. The method for manufacturing surface conduction nonlinear insulator by centrifugal technology according to claim 1, wherein the technical parameters in step 4) (2) are as follows: under the environment of 130 ℃, the rotating speed of the centrifuge is 140r/min, and the time is 30 min.

4. The method for manufacturing surface conduction nonlinear insulator by centrifugal technology according to claim 1, wherein the technical parameters in step 4) (3) are as follows: putting the mould into an oven with the temperature of 130 ℃ for secondary curing for 2 h.

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