JPH08140254A - Lead wire bushing for electric device - Google Patents

Abstract

PURPOSE: To prevent leakage of gas even when a function is decreased of a gasket between a lead conductor and a porcelain bushing. CONSTITUTION: In a lead wire bushing for an electric device, a lead conductor 1 is surrounded by a porcelain bushing 2 and led out to outside a device of the electric device from a terminal box of the electric device sealing gas in the device, so as to connect a conductor inside the device to a conductor outside the device. Gaskets 4a, 4b, provided in a clearance between the porcelain bushing 2 and the lead conductor 1 in lead-out part of the lead conductor 1 to outside the device for preventing leakage of gas in the device, and a plurality of layers of filling substances 6, 7, 8, provided in a clearance between the porcelain bushing 2 and the lead conductor 1 in a device inner side from a part provided with the gaskets 4a, 4b for preventing leakage of gas in the device, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead bushing of an electric device in which a conductor inside the machine and a conductor outside the machine are connected to each other.

[0002]

2. Description of the Related Art Generally, in a large electric device, gas is enclosed in the device to insulate the conductor part of the electric device and cool the heat generating part. In such an electric device, it is necessary to connect the conductor inside the machine and the conductor outside the machine without leaking the enclosed gas.
Therefore, such an electric device is provided with an outlet bushing. The outlet bushing is to surround the outlet conductor from the terminal box of the electric device with a porcelain insulator and draw it out of the electric device to connect the conductor inside the machine and the conductor outside the machine.

FIG. 2 is a sectional view showing the attachment of such an outlet bushing. The output bushing in which the output conductor 1 is surrounded by the porcelain insulator 2 is attached to the terminal box 3 of the electric device. Gaskets 4 a and 4 b are provided in the gap between the porcelain bushing 2 and the lead conductor 1 at the portion where the lead conductor 1 is pulled out of the machine. This prevents leakage of gas inside the aircraft.

FIG. 3 is an enlarged sectional view of the gaskets 4a and 4b in FIG. 2, showing a sealing structure between the lead conductor 1 and the porcelain insulator 2. The outlet conductor 1 for connecting the inside and outside of an electric device, in which gas is enclosed in the inside, is a porcelain insulator 2
Gaskets 4a and 4b are provided between the lead conductor 1 and the porcelain insulator 2 to prevent gas from leaking. Gasket 4a is gasket retainer 5a
The gasket 4b is supported by the gasket retainer 5b.

[0005]

However, the output conductor 1
If the function of the gasket between the insulator and the porcelain insulator 2 deteriorates, there is a risk of gas leakage, and in such a case, the gasket 4 must be replaced. The replacement of the gasket 4 is performed by disassembling the outlet bushing, but the phase separation busbar and the gas cooling device connected to the outlet bushing must also be disassembled. Therefore, the replacement work is difficult.

On the other hand, recently, the operating conditions of electrical equipment have become severe, and the function of the gasket between the lead conductor 1 and the porcelain bushing 2 is likely to deteriorate. For example,
The demand for larger capacity of turbine generators is increasing, and the current of the output bushing is increasing with the increasing capacity. When a large current flows through the output conductor 1, the resistance loss causes the temperature to rise to a high temperature, and the load conductor and the frequent start-stop cause a heat cycle, resulting in the deterioration of the function of the gasket between the output conductor 1 and the insulator tube 2. It's easy to do.

[0007] Further, due to an increase in the difference in power demand between daytime and nighttime, load fluctuations and starting / stopping tend to occur frequently. Therefore, for the gasket 4 used between the lead conductor 1 and the porcelain insulator 2, The usage conditions are more severe than ever before. Therefore, the deterioration is accelerated, the tightening force of the gasket 4 is reduced, and the risk of leakage of the in-machine gas is increasing, and safety and reliability are decreasing.

It is an object of the present invention to provide a lead bushing for an electric device which can prevent gas leakage even if the function of the gasket between the lead conductor and the porcelain insulator deteriorates.

[0009]

According to a first aspect of the present invention, a lead box conductor is surrounded by a porcelain tube from a terminal box of an electric device in which gas is sealed and is drawn out of the electric device. A lead bushing for electrical equipment that connects a conductor to a conductor outside the machine, which is provided in the gap between the porcelain tube and the lead conductor in the portion where the lead conductor is pulled out of the machine to prevent leakage of gas inside the machine. Gasket for
A plurality of layers of injecting substances are provided in the gap between the porcelain insulator tube and the outlet conductor on the inner side of the portion where the gasket is provided to prevent leakage of the in-machine gas.

According to the second aspect of the invention, the multi-layered injecting material of the first aspect of the invention is heat-resistant and solid, and the first-layer injecting material is insoluble in the first-layer injecting material. It is composed of three layers, a liquid second layer injectable material and a highly viscous liquid third layer injectable material.

In the third aspect of the invention, the first layer injection material of the second aspect of the invention is composed of silicone rubber or epoxy resin.

[0012] In the invention of claim 4, the second layer injection material of the invention of claim 2 is composed of animal or vegetable oil.

In a fifth aspect of the invention, the third layer injection material of the second aspect of the invention is composed of silicone oil.

[0014]

With this structure, when the function of the gasket between the lead conductor and the porcelain insulator deteriorates,
The first layer injection material injected into the portion in contact with the gasket fills the portion and prevents gas leakage. Furthermore, the second layer injection material and the third layer injection material injected in the subsequent stage are
The substance injected into the first layer penetrates into subtle cracks that cannot be completely filled up, and exerts a sealing effect. Especially, the viscosity of silicon oil, which is the third-layer injecting substance, changes little with temperature, and the high viscosity at the time of injecting is maintained even during the operation of the electric device to exert a great sealing effect.

[0015]

EXAMPLE An example of the present invention will be described below. FIG. 1 is an enlarged sectional view showing a sealing portion between a lead conductor 1 and a porcelain tube 2 of a lead bushing according to an embodiment of the present invention.

Although not shown, the outlet bushing of the present invention is provided in the terminal box 3 of the stator of the electric device in which the gas inside the machine is sealed, and connects the conductor inside the machine and the conductor outside the machine. Used for.

This lead bushing has a lead conductor 1 through which a current flows and a porcelain insulator 2 for insulating a high voltage. In the space between the lead conductor 1 and the porcelain insulator 2, a plurality of layers of injection substances are filled. Has been injected. That is, first, the heat-resistant and solid first-layer injecting material 6 is provided in the portion in contact with the gasket 4 and the gasket retainer 5. Then, a liquid second layer injecting material 7 which is insoluble in the first layer injecting material 6 is provided, and then a high viscosity liquid third layer injecting material 8 is provided. . Thus, multiple layers of injectable material are composed of these three layers.

Here, the first layer injection material 6 is made of silicon rubber or epoxy resin. This is because silicone rubber or epoxy resin has good heat resistance, and gasket 4
This is because it does not have an adverse effect on, and is optimal for injecting and curing the substance 5 to be solid-phased.

Next, the second layer injection substance 7 is composed of animal and vegetable oils. This is because it is a substance that is not soluble in the first-layer injected substance 6 injected previously, and this second-layer injected substance 7 is particularly useful when the first-layer injected substance 6 is silicon rubber. Oil is the best choice.

The third layer injection material 8 is composed of silicone oil. This is because silicone oil has a very high viscosity and changes little in viscosity with temperature. This is also because the third layer injecting substance 8 is in contact with the second layer injecting substance 7 and therefore is a substance 8 which is incompatible with the second layer injecting substance 7.

Now, it is assumed that the gasket 4 is deteriorated and the tightening force of the gasket 4 is reduced or the gasket 4 is damaged. In such a case, first, the gasket 4
Silicon rubber, which is the first layer injection material 6 injected into the portion in contact with, compensates for the defective portion of the gasket 4 and prevents gas leakage.

Further, the second layer injecting substance 7 and the third layer injecting substance 8 injected in the subsequent stage penetrate into a minute crack portion which cannot be filled up with the silicon rubber 5 which is the first layer injecting substance 6, and seal. Be effective. Although the output conductor 1 has a high potential, the newly added first layer injecting material 6 such as silicon rubber, the second layer injecting material 7 and the third layer injecting material 8 are gas filled in the machine, for example, hydrogen. The relative permittivity is higher than that of gas, and the electric field here is lower than that in the case of using conventional hydrogen gas, and discharge is less likely to occur.

[0023]

As described above, according to the present invention,
Since a plurality of layers of substances having a sealing effect are injected into the upper portion of the gasket between the porcelain insulator and the conductor, it is possible to provide a sealing device for an outlet bushing with improved safety and reliability against gas leakage.

Therefore, even if the gasket deteriorates during the operation of the electric device, it is possible to easily prevent the gas leakage without disassembling the outlet bushing, and the safety, the reliability, and the work for the gas leakage can be prevented. The property is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the attachment of a conventional outlet bushing.

FIG. 3 is an enlarged cross-sectional view of gaskets 4a and 4b in FIG.

[Explanation of symbols]

 1 Output conductor 2 Insulator pipe 3 Terminal box 4 Gasket 5 Gasket retainer 6 First layer injection material 7 Second layer injection material 8 Third layer injection material

Claims (5)

[Claims] 1. A method for connecting a conductor inside the machine and a conductor outside the machine by enclosing a lead conductor from a terminal box of the electric equipment in which gas is sealed in the machine and surrounding the output conductor with a porcelain pipe In the outlet bushing of the electric device described above, a gasket that is provided in the gap between the porcelain bushing and the outlet conductor in the portion where the outlet conductor is pulled out of the machine, and a gasket for preventing leakage of the in-machine gas, and the gasket. Of a plurality of layers of injection material for preventing leakage of the gas inside the machine, which is provided in a gap between the porcelain tube and the outlet conductor on the inside of the machine from the portion where Bush bushing. 2. The multi-layered injectable material comprises a heat-resistant solid first-layer injectable material, a liquid second-layer injectable material which is insoluble in the first-layer injectable material, and a high viscosity. The output bushing of an electric device according to claim 1, wherein the output bushing is composed of three layers including a liquid third layer injection substance. 3. The outlet bushing of an electric device according to claim 2, wherein the first layer injection material is silicon rubber or epoxy resin. 4. The outlet bushing of an electric device according to claim 2, wherein the second layer injection substance is animal or vegetable oil. 5. The outlet bushing of an electric device according to claim 2, wherein the third layer injection material is silicone oil.