JPH0370419A - Gel insulated bus-bar - Google Patents

Abstract

PURPOSE:To reduce the size of equipment and improve the safety and reliability by a method wherein an electrified conductor supported by insulators and a container in which the conductor is housed are insulated from each other with gel insulating material. CONSTITUTION:A conductor 7 is provided in a metal container 20 and supported by disc-type insulating spacers 21 and post-type insulating spacers 22. The metal container 20 is filled with gel insulating material 23. By the improvement of insulating performance and a thermal conductivity, the size of equipment can be reduced. As the inside of the container 20 is under an atmospheric pressure, even if a hole is produced by an arc when a failure occurs, the inside material is not discharged out explosively, so that high safety can be maintained. Even if metallic foreign substances are mingled in a manufacturing process, their movement is obstructed, so that the high reliability can be obtained from the viewpoint of insulating performance. Moreover, the insulation design of the bus-bar can be done easily and the large capacity bus-bars and small curvature design can be realized.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a gel insulated bus bar using a gel insulator as an insulating medium.

(Prior Art) Electric cables have been widely used as Cv cables and OF cables and have been put into practical use. Subsequently, with the development and spread of gas-insulated switchgears filled with SF6 gas, SF6 gas insulation technology was developed and established, and this technology has come to be applied to the field of electrical cables. The reasons for this are that long busbars of several tens of meters or more are used in some gas-insulated switchgear, that the structure can be used almost as is as a gas-insulated cable, and that it also has high voltage and large capacity. Then OF cable or Cv
Cables cannot be long enough for one drum, and are not suitable for installation in small curvatures. In addition, since the structure and role of the gas insulated cable are basically the same as the structure and role of the busbar part of the gas insulated switchgear, it will be described here as a gas insulated busbar.

Furthermore, since the gas insulated bus bar was originally constructed as a part of the gas insulated switchgear, the conventional gas insulated tH line will be explained starting with the gas insulated switchgear.

That is, as is clear from the single line diagram of the switchgear section of the substation shown in Fig. 3 and the arrangement examples shown in Figs. Vessel 2.
Main equipment parts such as disconnector 3 are made of SF6 with excellent insulation performance.
Since it is insulated by gas, it can be configured extremely compactly as shown in section B in the figure, but since the lead-in part with the overhead line is received by the bushing 5 which is insulated in the air, the main part of the gas insulated switchgear is connected from the bushing 5. It is necessary to connect to the equipment section with a long gas insulated bus bar 4. This gas insulated bus 4
basically has the same structure as the bus bar included in the main equipment section.

The structure of such a gas insulated bus bar is shown in FIG.

That is, a high-voltage conductor 7 for current-carrying is disposed in a metal container 6 set at ground potential, and a conical insulating spacer 8 and a post-shaped insulating spacer 9 are disposed to support this conductor 7. . Also, inside this metal container 6, a high voltage conductor 7 is provided.
In order to insulate the high voltage between the metal container 6 and the metal container 6, SF6 gas 10 with excellent insulating performance is applied to the valve 12 at a predetermined pressure (
Usually, it is filled under pressure of about 3 kg/cm2).

Further, the post-shaped insulating spacer 9 has the role of insulating and supporting and fixing the conductor 7, but the conical insulating spacer 8
further has the role of separating the gas from the adjacent busbar section. Note that the reason why the conical insulating spacer 8 usually has a conical shape is that its dielectric constant is approximately six times as large as the dielectric constant of SF6 gas, which is 1. This is to increase the creepage distance of the insulator since it disturbs the potential distribution between the metal container 6 and the metal container 6, and some concentration of electric field is unavoidable.

(Problems to be Solved by the Invention) However, in the conventional gas insulated bus bar configured as described above, there were problems to be solved as described below.

In other words, in order to ensure the required insulation performance, the gas pressure should be adjusted to 3 to 5.
Although the metal container 6 is pressurized and sealed at a pressure of Kg/cm2, care must be taken to ensure that the joints of the metal container 6 can maintain airtightness at all times. This is because if a gas leak were to occur at the joint of the metal container, the required insulation performance would no longer be maintained, and the line in question at the substation would have to be shut down. Further, if minute metal foreign matter is mixed inside the metal container, the foreign matter will reciprocate between the conductor 7 and the metal container 6 when an operating voltage is applied, and there is a risk that dielectric breakdown will occur eventually. Furthermore, the high voltage conductor 7 has several thousand A
When a current of 1 is applied, heat is generated in the conductor 7 and the connecting portion 11. The size of the metal container, the dimensions of the conductor, etc. are designed so that this temperature rise is within the allowable value, but since the heat transfer medium between the conductor and the metal container is SFb gas, the transfer efficiency is low. Unfortunately, in order to reduce the amount of heat generated, it is necessary to increase the diameter of the conductor. However, if the conductor diameter is increased, the required insulation distance between the conductor and the metal container is required for insulation performance, so the tank diameter has to be increased, resulting in a larger overall size. There was also. In addition, in the event that an accident occurs and the circuit breaker trips and is removed, it will take a considerable amount of time to determine the location where the accident occurred, even if it is determined that the area is protected by a current transformer. There are also some drawbacks. Furthermore, if the fault current continues to flow to some extent and the thickness of the container is melted by the arc, the pressurized gas inside the container will be released explosively from the melted hole, causing substation maintenance personnel to safety was also concerned.

The present invention was proposed in order to eliminate the above-mentioned drawbacks, and its purpose is to provide a gel-insulated busbar that can reduce the size of equipment, is highly safe, and has excellent reliability compared to gas-insulated busbars. Our goal is to provide the following.

[Structure of the Invention] (Means for Solving the Problems) The gel insulated bus bar of the present invention stores a conductor of a live part inside a container, supports this conductor from the container with an insulator, and has a conductor inside the container. It is characterized by being filled with a gel insulator to insulate the conductor and the container.

(Function) According to the gel insulated bus bar of the present invention, the inside of the container can be maintained in an insulated state by the gel having superior insulation performance compared to SF6 gas, so it is possible to downsize the equipment, and the container Since there is no need to pressurize and encapsulate the material inside, safety is improved and insulation reliability can also be greatly improved.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Incidentally, the same members as those of the conventional type shown in FIG. 6 are given the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG.
A conductor 7 is disposed within the conductor 7 and is supported by a disc-shaped insulating spacer 21 and a post-shaped insulating spacer 22. Further, this conductor 7 is electrically connected to an adjacent conductor 7 via a connecting portion 11 so as to ensure the required current carrying performance. Furthermore, the metal container 20 is filled with a gel insulator 23 . Further, the metal container 20 is provided with a valve 24 for injecting gel into the container, and a thermal expansion/contraction absorbing section 2 for absorbing thermal expansion/contraction of the gel insulator 23.
5 is provided.

Table 1 shows the characteristics of silicon gel as an example of the gel insulator 23 filled in the metal container 20. (Margin below) Table 1 General characteristics of silicone gel: Silicone gel is made by mixing liquids A and B and hardens into a gel-like state after about 16 hours, and is a fluid liquid at the beginning of mixing. While it has fluidity, it is injected into the container through the valve 24 shown in FIG. 1 to fill it. After that, it hardens and becomes a gel. Furthermore, when filling the gel into a container, by evacuating the container before filling the gel, air bubbles within the gel can be completely removed before filling. Furthermore, the disc-shaped insulating spacer 21 is used to separate the gel-insulated busbar from the adjacent gel-insulated busbar, and in the event that an accident occurs within the busbar, it is used to limit the spread of the accident and when injecting the gel solution. The placement position is appropriately set based on the amount that can be filled in an injection time commensurate with the curing time.

The gel insulated bus bar of this embodiment having such a configuration has the following advantages. That is, SF6 gas 3Kg/
Approximately 1.4 times compared to cm2, SF6 gas 4 Kg/
Since the insulating performance is approximately 1.5 times that of cm 2 , the dimension between the conductor 7 and the metal container 20 can be reduced in the case where the dimension between the conductor 7 and the metal container 20 is determined based on the insulating performance. Furthermore, in cases where the diameter of the container is determined thermally in terms of current carrying capacity, the Vegel insulator has much better thermal conductivity than SF6 gas, so it is possible to downsize the container. moreover,
In the case of gas-insulated busbars, if metal foreign matter gets into the busbar during manufacturing, the metal foreign matter will move due to voltage application, resulting in a decrease in insulation performance, but in the case of gel-insulated busbars, when the gel hardens, it will become agar-like. Therefore, even if foreign matter gets mixed in, the foreign matter will not move due to voltage application, and the initial insulation performance can be maintained semi-permanently for a long period of time, resulting in a highly reliable bus bar. In addition, since gel insulators do not need to be pressurized, the container in which they are stored does not need to withstand high pressure, but only needs to be able to withstand vacuuming of the container before injecting it as a liquid, that is, a differential pressure of 1 kg/cm2. Therefore, the structure of the container does not require much strength compared to a gas-insulated bus bar. Therefore, in the case of constructing the container with a metal container, it is possible to use a material with a thinner plate thickness, and furthermore, it is also possible to use a plastic container. In addition, when using a plastic container, a metal coating 31 is applied to the inner surface of the plastic container 30 as a shield, as shown in FIG. 2, to prevent the high voltage of the high voltage conductor 7 from being induced outside the container. There is a need. At this time, a similar shielding effect can be obtained by using a conductive plastic material as the container material, and in this case, a metal coating is not necessary. In this way, it becomes possible to reduce the weight of the bus bar, which not only greatly improves the workability of transportation and installation, but also significantly shortens the installation period. Furthermore, even if an accident occurs inside the busbar, the inside of the container is under atmospheric pressure, so even if the container is punctured by an arc, the contents will not be released explosively, making it extremely safe. A high bus line can be obtained.

In addition, as mentioned above, it is possible to use a plastic container due to its strength, so a transparent plastic material is used and the metal shield on the inside of the container is made into a thin film so that the inside can be seen through from the outside. With this configuration, the inside can be visually observed from the outside during operation, and even if corona occurs in a part of the conductor, the location can be determined before an accident occurs.

Furthermore, since the dielectric constant of the gel insulator is about 3, it is possible to make the dielectric constant of the insulator (usually an epoxy resin) that supports the conductor part as close to the dielectric constant of the gel insulator as possible. That is, the dielectric constant of commonly used epoxy resin is approximately 6.
However, it is possible to lower it to about 4. In this way, the dielectric constants of the two types of insulating media used to ensure insulation between the conductor and the container are made similar by using materials with similar physical properties, thereby making it possible to apply voltage to the high-voltage conductor 7. At this time, it becomes possible to significantly reduce the electric field concentration at and near the interface of two insulating media,
The insulation design of the bus bar becomes easy, and further downsizing becomes possible.

In this way, the present example is not only suitable for larger capacity and smaller area installation than OF cables and CV cables, but also superior in terms of insulation performance and thermal design compared to gas-insulated busbars. Since it has excellent performance, it can be significantly downsized. In addition, since the inside of the container can be kept at atmospheric pressure without being pressurized, it is possible to reduce the weight of the container, improve transportability, and significantly shorten the installation period. However, high-pressure gas is not released explosively, so a high level of safety can be ensured. Moreover, since it is possible to prevent the behavior of unavoidable situations such as the contamination of metal foreign matter during manufacturing, a bus bar with high reliability in terms of insulation performance can be obtained. In this way, gel-insulated busbars can be used as power cables, and by insulating only the busbar section that does not include the switch, the reliability of the entire switchgear can be greatly improved. is possible.

[Effects of the Invention] As described above, according to the present invention, a conductor of a live part is housed inside a container, this conductor is supported from the container by an insulator, and the container is filled with a gel insulator. By simply maintaining insulation between the conductor and the container, it is possible to downsize the equipment and provide a gel-insulated bus bar that is highly safe and reliable.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the gel insulated busbar of the present invention, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, FIG. 3 is a single line diagram of a gas insulated switchgear, and FIG. The figure is a plan view showing an example of equipment arrangement based on the single-line diagram in Fig. 3, Fig. 5 is a view taken along the line A-A in Fig. 4, and Fig. 6 is a sectional view showing an example of a conventional gas-insulated bus bar. It is. 1... Main bus bar, 2... Circuit breaker, 3... Disconnector, 4
...Gas insulated bus bar, 5...Bushing, 6...Metal container, 7...High voltage conductor, 8...Conical insulating spacer, 9...Post type insulating spacer, 10...SF6
Gas, 11...Connection, 12...Valve, 20...
・Metal container, 21...Disc-shaped joint spacer, 22...
・Post type insulating spacer, 23...Gel insulator, 24
... Valve, 25... Heat expansion and contraction absorption part.

Claims (1)

[Claims] A gel insulation characterized in that a conductor of a live part is housed inside a container, the conductor is supported by an insulator from the container, and a gel insulator is filled in the container to insulate between the conductor and the container. Bus line.