JPH03251014A - Gas insulating bus - Google Patents

Abstract

PURPOSE:To improve insulating characteristic and secure high reliability by applying an insulating coat on the internal surface of a vessel, in a specified area limited from an insulating spacer. CONSTITUTION:In a specified area from an insulating spacer 3 for supporting a high-tension conductor 3, an insulating film 5 is applied. For the insulating film 5, the gel agent of liquid rubber, liquid polymer, or the like is suitable. On the internal surface of a vessel 1, the insulating coat 5 is previously applied, and metallic foreign matters are prevented from being attached to the insulating spacer 3.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a gas insulated bus bar used in a power transmission/substation or a switchyard, and particularly relates to a gas insulated bus bar with improved electrical insulation properties. .

(Prior art) Gas insulated busbars are made by inserting a high voltage conductor into a sealed container, supporting and fixing the high voltage conductor with an insulating support called an insulating spacer, and filling the surrounding gas space with an insulating gas with excellent electrical properties. For example, SF is one in which gas is sealed under pressure. Its characteristic feature is that it is capable of transmitting high voltage and large current, so it is widely used in power transmission substations and switchyards. In recent years, gas insulated buses have been required to have a larger capacity due to higher voltage and larger current, as well as higher reliability and smaller size due to higher quality electricity.

Particularly in recent years, with advances in manufacturing technology and development in analysis technology, gas insulated busbars have become smaller, and in insulation designs using SFG gas, the electric field strength at the time of design is almost reaching its physical limit. Under these circumstances, in order to achieve further miniaturization, it is extremely important to remove or neutralize the metal foreign matter in order to ensure reliability. That is, while SF and gas have excellent insulating performance, it has been revealed that the insulating performance deteriorates significantly in areas where the electric field is locally strong, that is, in the case of so-called unequal electric fields. In particular, if metallic foreign matter gets mixed into the gas insulated bus bar for some reason, the metallic foreign matter will move around in the gas space due to the electric field, and in some cases it will stick to the insulating spacer, reducing the dielectric breakdown voltage, which is a big problem that needs to be solved. It had become. For this reason, it is used as a countermeasure against metal foreign matter.

Addition of trap devices and implementation of insulation coatings have been carried out.

(1llii which the invention seeks to solve.

However, adding a trap device involves attaching a new device to the device, which is not desirable from the standpoint of miniaturization and has the problem of increasing manufacturing costs. Furthermore, even if it is technically possible to coat the insulating coating up to the center of the bus bar if the bus bar is long, there is a problem in terms of cost, which has been an issue to be solved.

The present invention was proposed to solve the above-mentioned drawbacks, and by improving the insulation coating method, it improves the insulation properties against metal foreign matter contamination, which is a weak point of SF and gas, and ensures high reliability. In addition, the present invention provides a gas insulated bus bar that does not increase the internal dimensions of equipment. An insulating coating is provided in the vicinity of an insulating spacer that supports a conductor, particularly within 1 meter from the insulating spacer to prevent metal foreign matter from adhering to the insulating spacer.

(Function) That is, according to the present invention, it is possible to prevent metal foreign matter from adhering to the insulating spacer, which is one of the cases where the dielectric breakdown voltage decreases significantly. That is, even if metallic foreign matter is mixed into the inner surface of the container near the insulating spacer, by providing an insulating coating, it is possible to increase the electric field strength at which the metallic foreign matter starts standing up and floating due to the electric field. This prevents the metal foreign matter from moving, thereby preventing it from adhering to the insulating spacer. In addition, even if a metal foreign object moves, the insulating coating applied within 1 meter of the insulating spacer prevents it from coming into direct contact with the container, preventing it from moving and preventing it from adhering to the insulating spacer. It can be prevented. This makes it possible to prevent the dielectric breakdown voltage of SF and gas from decreasing.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In Fig. 1, 1 is a sealed container, 2 is a high voltage conductor,
Reference numeral 3 indicates an insulating spacer for supporting a high voltage conductor, 4 indicates an insulating gas, and 5 indicates an insulating coating, and the insulating coating is provided in a range of 1 meter or more from the insulating spacer 4. This insulating coating 5 is preferably made of a gel material such as liquid rubber or liquid polymer.

Usually, it is thought that metal foreign matter lies on the inner surface of the lower part of the container due to the action of gravity.

In order to investigate the effect of the insulating coating under such conditions, FIG. 2 shows the results of an experiment of the electric field caused by the electric field of the metallic foreign object when the inner surface of the container was coated with an insulating coating and when it was not.

The experiment was conducted using aluminum wire with a thickness of 0.25 mm, but the standing electric field was approximately 5 kVrms without insulation coating.
/3, but by applying insulation coating it can be reduced to about 11kVr.
It is possible to increase the standing electric field by more than twice as much as ms/■. That is, by applying an insulating coating to the inner surface of the container in advance, the standing voltage of the foreign metal particles due to the electric field increases and the foreign metal particles do not start moving.

This can prevent metal foreign matter from adhering to the insulating spacer.

Also, foreign metal particles that have gotten mixed in for some reason begin to move away from the insulating spacer due to the electric field.

Even if the metallic foreign matter approaches the insulating spacer, the insulating coating can prevent direct contact between the container and the metallic foreign matter.

In such cases, the force caused by the electric field becomes smaller, resulting in weaker movement. Usually, a gas-insulated bus bar with a coaxial cylindrical structure is used, but in this case, the electric field is stronger the closer it is to the high-voltage conductor, so dielectric breakdown is reduced. However, according to this method, even if metal foreign matter should adhere to the insulating spacer, it will remain in the low electric field area, making it difficult to cause dielectric breakdown.

Therefore, the reliability of the gas insulated bus bar can be improved. In this case, the range to be coated with insulation was set at 1 meter, but experiments on the behavior of metallic foreign objects showed that the axial movement of the bus bar was slower than the radial movement, and was sufficient to prevent adhesion to the insulating spacer. This is because a significant effect can be expected.

It also has the advantage of being easy to work with when applying an insulating coating.

As described above, according to this embodiment, by applying the insulating coating 5 to the area of the container within 1 meter from the spacer 3, it is possible to prevent metal foreign matter from adhering to the insulating spacer 3. Thereby, deterioration of the insulation performance of the gas insulated bus can be prevented, and the reliability of the gas insulated bus can be improved. Also.

There is no need to change the dimensions of the container, which is advantageous in manufacturing. Furthermore, this method is considered to be particularly effective when the length of the gas insulated bus bar is long. That is, when the gas insulated bus bar is long, it is not desirable from the viewpoint of manufacturing cost, even if it is technically possible to provide an insulating coating at the center of the bus bar. In particular, this tendency becomes more problematic as the dimensions of the generatrix become smaller. However, according to this embodiment, since the range to which the insulation coating is applied is limited, it is advantageous in terms of cost.

In the above description, an example has been described in which the present invention is applied to a gas insulated bus bar having a cone-shaped insulating spacer.

FIG. 3 shows another embodiment of the present invention, which is characterized in that the insulating spacers are columnar. In this case, the insulating coating 5 is applied only to a portion within 1 meter from the central axis of the insulating spacer 6. Even in this case, the aforementioned effects can be obtained as well. In addition, other electrical insulating equipment such as transformers, lightning arresters,
It is clear that similar effects can be obtained even when applied to equipment equivalent to a bus bar in which a conductor is supported by an insulating spacer, such as the main body of a gas-insulated switchgear or an air-insulated bus bar.

Note that the material for the insulating coating may be an epoxy paint, liquid rubber, liquid polymer, or other gel agent. In particular, when a gel is used, it not only has electrical insulating properties but also has elasticity that makes it resistant to mechanical shock, and even when a mechanical impact is applied to the container, the gel absorbs the impact force. Therefore, it has the feature of being able to prevent metal foreign objects from mechanically standing up.

〔Effect of the invention〕

As described above, according to the present invention, from the insulating spacer
By applying an insulating coating to the inner surface of the container within a meter,
The insulation characteristics of the gas insulated bus bar against metal foreign objects can be improved. This makes it possible to provide a highly reliable gas-insulated bus bar. Further, according to the present invention, the size of the device can be reduced without causing a local increase in the size of the device or an increase in manufacturing cost.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a gas insulated bus bar showing one embodiment of the present invention, Fig. 2 is a diagram showing experimental results showing the effect of insulation coating, and Fig. 3 is a gas insulated bus bar showing another embodiment of the present invention. It is a sectional view of a generatrix. 1... Container, 2... High voltage conductor, 3...
...Insulating spacer, 4...Insulating gas. 5... Insulating coating, 6... Column-shaped insulating spacer.

Claims (1)

[Claims] In a gas-insulated bus bar in which a high-voltage conductor is inserted into a container filled with insulating gas and the high-voltage conductor is supported and fixed by an insulating spacer, an insulating coating is applied to the inner surface of the container within a range of 1 meter or less from the insulating spacer. A gas insulated bus bar characterized by being subjected to.