JP3873529B2 - Gas insulated switchgear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas-insulated switchgear, and more particularly, to a gas-insulated switchgear with improved reliability for electrical gas-insulating performance.
[0002]
[Prior art]
In general, a gas-insulated switchgear contains circuit breakers, disconnectors, ground switches, instrument transformers, instrument current transformers, current-carrying conductors and busbars that electrically connect them in several sealed containers. It is a device filled with an insulating gas, and is widely installed in electrical stations such as substations because it is excellent in downsizing, insulation performance and safety.
[0003]
FIG. 3 shows a circuit breaker arranged in a conventional gas insulated switchgear. In FIG. 3A, insulating cylinders 2a and 2e, conductors 2b and 2d, and a blocking unit 2c are arranged with respect to a horizontally installed container 1b. Further, it is connected to a bushing for drawing another power device or cable via the conductors 2f and 2g. Moreover, when this conventional circuit breaker is arranged in three phases horizontally, it becomes as shown in FIG. When a bushing is attached, air insulation between the bushing phases is required, and at least a certain distance L is required.
[0004]
If metal foreign matter is mixed into the switchgear container for any reason, such as during assembly, it tends to collect at the bottom of the inner surface of the container. It is known that when a metal foreign matter exists at least at the bottom of the inner surface of the container, the insulation performance of the portion where the metal foreign matter exists is deteriorated due to movement in gas, levitation, or adhesion to the surface of the insulator.
[0005]
For this reason, conventionally, if there is no metallic foreign matter, the size of the circular container 1a in FIG. 1 is large enough that the metallic foreign matter is present and does not adhere to each device even if the metallic foreign matter moves and floats. It becomes a circular container 1b, which hinders the reduction of the container. In addition, a special trap device for capturing metal foreign objects is provided in the circular container 1a of a size that does not consider metal foreign objects, as disclosed in, for example, Japanese Patent Laid-Open No. 10-234113. By doing so, the deterioration of the insulation performance inside the gas insulated switchgear is prevented.
[0006]
[Problems to be solved by the invention]
The above-mentioned conventional technique is expensive because the container becomes large or a trap device for capturing a foreign object is provided. In addition, for example, in a switchgear container where mechanical vibration or gas flow acts during breaker operation, even if a trap device that simply captures metal foreign matter is provided in the container, the metal foreign matter captured by the trap device is opened and closed again. There is a risk of scattering inside the device container and adversely affecting the insulation performance inside the gas insulated switchgear. Further, in the system in which various devices are provided at the inlet of the trap container, there is a problem that the electric field at that part is disturbed and the switchgear container itself is enlarged due to the electric field concentration.
[0007]
Moreover, when the switchgear container is enlarged, the volume in the container is increased, and the amount of SF6 gas or the like designated as a greenhouse gas is increased.
[0008]
The purpose of the present invention is to ensure high reliability of electrical insulation performance at a low price even when a metallic foreign object is present, as compared to a true circular container, and to thereby provide the same level of reliability of electrical insulation performance. An object is to provide a gas insulated switchgear having a reduced interphase distance and a reduced installation area as compared with a gas insulated switchgear having a true circular container.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, in the gas insulated switchgear according to the present invention, sufficient insulation between the electrical equipment and the bottom surface of the container is achieved compared to the top and left and right surfaces by means such as changing the curvature of the top and bottom surfaces of the switchgear container. Secure the distance. The above-described container can be easily realized at a low cost by being manufactured by casting. In addition, it is possible to easily form the trap container integrally by manufacturing the container by casting.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 shows a first embodiment of the present invention and shows an AA cross-section corresponding to FIG. By changing the curvature R1 of the upper surface and the curvature R2 of the lower surface of the container 1 of the present invention, the insulation distance in the downward direction is at least longer than the insulation distance in the upper and left and right directions with respect to the blocking unit 2c. As a result, the reliability of the dielectric strength with respect to the foreign matter collected on the bottom surface of the container is low, and the reliability of the dielectric strength with respect to the foreign matter gathered on the bottom surface of the container 1 is ensured as compared with the conventional circular container 1a having the radius R1 of the container 1 of the present invention. Yes. Thereby, since the lateral width does not change, the installation area is not changed, and the reliability with respect to the foreign matter is improved. In addition, compared with the conventional circular container 1b having the radius R2 of the container 1 of the present invention, the container 1 of the present invention has an upper and left / right direction that is the same as that of the container 1 of the present invention. Can be small. By reducing the size of the container, it is possible to reduce the weight, reduce the installation area, and reduce the gas amount due to the volume reduction.
[0012]
FIG. 2 shows an example of the electric field analysis result on the inner surface of the container shown in FIG. The electric field value of the container 1 of the present invention is an electric field value equivalent to that of the conventional circular container 1a that does not consider the influence of foreign substances from the upper surface to the lateral surface of the container. In addition, the electric field value from the lateral surface to the lower surface of the container is as low as that of the conventional circular container 1b having a high dielectric strength against foreign substances gathering on the lower surface of the container, and the container can be reduced while maintaining the insulation reliability. I understand. In addition, by applying an electrostatic paint to at least the lower surface of the container, the reliability of the dielectric strength against foreign matters gathering on the lower surface of the container becomes higher.
[0013]
4 and 5 show another embodiment. In FIG. 4, like FIG. 1, the container 1 of the present invention has a lateral width comparable to that of the conventional container 1a and a lower space length comparable to that of the conventional circular container 1b. Thereby, higher reliability of dielectric strength against foreign substances gathering on the lower surface of the container than the conventional container 1a is obtained, and the upper and left and right directions are made smaller than those of the conventional container 1b having reliability of dielectric strength against foreign substances gathering on the same level of the container. is doing. In FIG. 5, the container 1 of the present invention has a greater width than that of the conventional container 1a in order to obtain a higher reliability of insulation against foreign substances that collect on the lower surface of the container than the conventional container 1a. The upper and left and right directions are smaller than those of the conventional container 1b having the reliability of the dielectric strength.
[0014]
Similarly, even if the interruption | blocking part unit 2c in FIG.1, FIG.4, FIG.5 is replaced with the insulation cylinders 2a and 2e, the conductors 2b and 2d, a disconnecting switch, a grounding switch, an instrument transformer, and an instrument current transformer The same can be said even if the units are replaced with units such as energizing conductors and buses connecting them.
[0015]
FIG. 6 shows a case where the container of FIG. Compared to the case where the conventional container 1b having the reliability of the dielectric strength against the foreign substances gathered on the same level of the container is arranged in three phases, when the container 1 of the present invention is compared, the horizontal direction can be greatly reduced. Also in the frame for fixing the container, the container fixing frame 3 of the present invention can be greatly reduced compared to the conventional container fixing frame 3b.
[0016]
If the left and right direction is significantly reduced, the distance L required for air insulation between the bushing phases may not be obtained, which is a problem.
[0017]
On the other hand, as shown in FIG. 7, by tilting at least two of the present invention containers juxtaposed in three phases, it is possible to secure a distance L necessary for air insulation between the bushing phases. Further, by tilting at least one, the fixed frame 3a can be further reduced than the fixed frame 3.
[0018]
FIG. 8 has the same outer shape as the conventional container 1b, and shows the case where only the inner surface of the cross section of the container changes the curvature R1 of the upper surface and the curvature R2 of the lower surface as in the case of the inventive container of FIG. As a result, the reliability of the dielectric strength with respect to the foreign substances gathering on the lower surface of the container 1b is substantially the same as that of the conventional container 1b, and the volume is greatly reduced by the hatched portion in the figure, and the greenhouse gas such as SF6 gas. This is a significant reduction in weight.
[0019]
9 is similar to the inventive container of FIG. 1, the outer surface of the container 11 of the present invention changes the curvature of the upper surface and the lower surface of the container, the trap space 13 is provided on the inner surface of the container 11 of the present invention, and the communication portion 14 is formed in the trap space 13. It is made smaller than the maximum diameter or the maximum width. Since the foreign matter is captured by the trap space 13 and the width of the communication portion 14 is narrow, the foreign matter is difficult to jump out. Therefore, the reliability of the dielectric strength with respect to the foreign material which is the same width as the conventional container 1a and collects on the lower surface of the container is significantly improved as compared with the conventional container 1a. In addition, the container 11 of the present invention can be easily manufactured in large quantities by manufacturing it by casting, for example.
[0020]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, even if metal foreign matter is mixed in or generated in a gas insulated switchgear, there is an effect of ensuring a sufficient electrical insulation characteristic and providing a highly reliable gas insulated switchgear at low cost. . In addition, there is an effect of further reducing the volume and installation area of the conventional gas insulated switchgear having the same level of electrical insulation reliability.
[Brief description of the drawings]
FIG. 1 is a sectional view of a circuit breaker disposed in a gas switchgear according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of an electric field analysis result on the inner surface of the container of the present invention.
FIG. 3 is a diagram showing a conventional circuit breaker structure and a three-phase parallel arrangement example.
FIG. 4 is a cross-sectional view of a circuit breaker according to another embodiment of the present invention.
FIG. 5 is a sectional view of a circuit breaker according to another embodiment of the present invention.
FIG. 6 is a diagram showing a three-phase parallel arrangement example according to an embodiment of the present invention.
FIG. 7 is a diagram showing an example of a three-phase parallel arrangement according to an embodiment of the present invention.
FIG. 8 is a cross-sectional view of a circuit breaker according to another embodiment of the present invention.
FIG. 9 is a cross-sectional view of a circuit breaker according to another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... This switchgear container of this invention, 1a, 1b ... Conventional type circular switchgear container, 2a, 2e ... Insulation cylinder, 2b, 2d ... Conductor, 2c ... Breaking unit, 2f, 2g ... Conductor, 3, 3a, 3b ... Opening and closing device fixing frame, R1 ... curvature of the upper surface of the inner surface of the opening and closing device container 1 of the present invention, R2 ... curvature of the lower surface of the inner surface of the opening and closing device container 1 of the present invention, L ... distance required for air insulation between the bushings Device container, 13 ... trap space, 14 ... communication part.

Claims (2)

In a sealed container in which the insulating gas is sealed, breaker, disconnector, earthing switch, instrument transformer, current transformer, and current carrying conductors, mother lines are arranged to connect them electrically In gas insulated switchgear,
By changing the curvature of the upper surface of the container and the curvature of the lower surface in the cross section of the sealed container, the insulation distance in the downward direction is increased with respect to the insulation distance in the container cross-section upper and left and right directions with respect to the breaker of the circuit breaker. A gas-insulated switchgear characterized in that containers are arranged in three phases and at least one of the sealed containers is inclined with the longitudinal direction of the sealed container as a rotation axis .   The gas insulated switchgear according to claim 1, wherein electrostatic coating is applied to at least a lower portion of the inner surface of the sealed container.

Images