JPS61193412A - Gas insulated electric device - Google Patents

Abstract

PURPOSE:To improve the reliability of the title electric device by a method wherein opposingly positioned tanks are connected by a material having a high dielectric constant which suppresses a high frequency surge voltage, thereby enabling to prevent the creeping dielectric breakdown and the penetrating breakdown generated between flange parts of the tanks. CONSTITUTION:Insulating collars 100 are composed of the material having high dielectric constant such as titanium oxide, barium titanate and the like, for example. When surge overvoltage is generated on a center conductor 6, the surge voltage corresponding to the center conductor is generated on the outer cover. The valve of said surge voltage is greatly changed by the capacity between the terminals of an insulating mounting part. At this point, when an insulating spacer of high dielectric constant is provided at the insulating mounting part, it works as the low impedance for a high frequency surge voltage, and the outer cover surge voltage can be reduced. Accordingly, the creeping dielectric breakdown and the penetrating breakdown generated between the flanges of the opposing tanks can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to gas-insulated electrical equipment for electrical stations such as power generation and substations.

[Conventional technology] Conventionally, the air insulation method was the mainstream for the configuration of electrical stations, but in recent years, GIS (
Gas Insulating System) method is often used.

According to this method, since SF6 gas having high withstand voltage characteristics is used as the insulating body, miniaturization and high voltage can be easily realized.

A conventional gas insulated electrical device will be explained based on the drawings. Figure 4 is a cross-sectional view of a conventional gas-insulated electrical device, and Figure 5 is a cross-sectional view of a conventional gas-insulated electrical device.
Detailed enlarged view of the dotted line (C) in the figure, Figure 6 is the ■■ of Figure 4.
FIG. 7 is a perspective view of the insulating collar.

In the figure, (1), (2), and (3) have flange parts (la), (2a), ('2b), and (3b) at their respective ends.
is formed, □F tank is filled with SF6 gas,
m, (!i) are the flange parts (la), (2a) and (2
b) Disc-shaped insulating spacers held from both sides by (3b) and (8) are tanks (1) and (2), respectively.
, (3) is supported within the insulating spanner (0° (5) through the central part of the tank (1).

(2), a center conductor electrically insulated from (3),
(7) and (8) are bolts and nuts that mechanically fasten the flanges (la) and (2a) via the insulating spacer (1), and (8) are the bolts and nuts that connect the tanks (1) and (2) electrically. (lO) is a ground bar, and (11) is a ground mesh.

The conventional gas-insulated electrical device is configured as described above, and the dielectric current (i+) generated in the tanks (+), (2), and (3) by the current (i6) flowing through the center conductor (8).
, (i2), (i3) are the respective tanks (1), (
2).

The length of (3) is suppressed by being insulated and sectioned by insulating collars (8). Further, the grounding bar (lO) electrically connects the grounding mesh (11) of the substation and the tank (2) with low impedance so that the potential of the tank (2) does not rise. Usually, a grounding hole (10) is used to prevent induced current (12) from flowing into the tank (2).
is connected to only one point of the tank (2).

[Problems to be Solved by the Invention] Normally, when a commercial frequency voltage is applied to the center conductor (6), the flange portions (la) of the tanks (1), (2), (3), (2a) and (2b), (3b)
Almost no voltage is generated between them. However, not only the commercial frequency voltage is applied to the center conductor (8), but also the so-called switching surge caused by the operation of a switch such as a circuit breaker or disconnector, or the center conductor (6). A surge overvoltage such as a so-called lightning surge caused by a lightning strike to an electrically connected overhead power transmission line (not shown) is also applied.

Such surge overvoltages can enter gas-insulated electrical equipment and cause the tank (1
), (2), and (3) also generate a surge voltage (ma) corresponding to the surge overvoltage V of the center conductor (6), which also occurs at approximately the speed of light. However, tank (1),
(2) and (3) Because there is an insulating collar (9) between them to suppress the induced current, the tank (2)
) The surge voltage (v) that has been the main cause of the insulating collar (9)
For this purpose, the flange part (2b).

A surge overvoltage (Vs) occurs between (3b) and (3b). According to research results, this surge overvoltage (vs) has a maximum of about 20% of the surge overvoltage V of the center conductor (6) and a frequency of 5.
0 to 10 megahertz (MHz), but there was a problem in that it caused creepage failure and through-hole failure of the insulating collar (9).

This invention was made to solve the above-mentioned problems, and its purpose is to provide a highly reliable gas-insulated electrical device by suppressing the surge overvoltage generated in the insulating collar interposed between the flanges. shall be.

[Means for Solving the Problems] In a gas insulated electrical device according to the present invention, an insulating mounting member for connecting adjacent tanks is made of a high dielectric constant material.

[Function] In this invention, the insulating mounting member connected between the opposing flange parts is made of a high dielectric constant material and acts as a low impedance at high frequencies, so high frequency surge voltage is mainly applied between the flange parts. When passing through the structure, it is possible to reduce the voltage between them and prevent creepage breakdown or penetration breakdown of insulating spacers, etc. Also, if only normal commercial frequency voltage is applied or if it is applied to the center conductor, high It becomes an impedance and can insulate the outer jacket like a conventional insulating collar.

[Embodiment] Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 3, in which the same parts as those of the conventional example are denoted by the same reference numerals.

Figure 1 corresponds to the conventional Figure 5, Figure 3 corresponds to the conventional Figure 6, and Figure 2 is a graph showing the relationship between the capacitance between the terminals of the insulation mounting part and the jacket surge voltage. It is.

In the figure, tanks (1), (2), flange part (la)
.

(2a), the insulating spacer (1), the bolt (7), and the nut (8) are the same as the conventional ones shown in FIGS. 4 to 7. Therefore, (100) is, for example, titanium oxide,
This is an insulating collar made of a high dielectric constant material such as barium titanate.

In the above configuration, when a surge overvoltage occurs in the center conductor (6), a surge voltage corresponding to the center conductor is also generated in the outer cover, but its value varies greatly depending on the capacitance between the terminals of the insulating mounting portion. This state is as shown in FIG. Therefore, if an insulating spacer with a high dielectric constant is provided at the insulating mounting part, it will act as a low impedance against high-frequency surge voltages and reduce the jacket surge voltage. Creeping dielectric breakdown and penetration breakdown can be prevented from occurring.

Note that the insulating collar (100) is different from the conventional insulating collar (8).
), but part of it is made of the above-mentioned high dielectric constant insulating collar, and the rest is made of the conventional insulating collar (
8), the entire gas insulated electrical device can be maintained with sufficient mechanical strength.

In the above embodiment, the insulating collar (100) is made of a high dielectric constant material, but the bolt (7) and nut (8)
) may be made of a high dielectric constant material, or a material made of the above material may be attached between the flanges on the outside of the tank.

[Effects of the Invention] As explained above, this invention connects opposing tanks with a high dielectric constant member that suppresses high frequency surge voltage, thereby preventing creeping dielectric breakdown between the flanges of the tanks. This has the effect of preventing penetration failure and improving the reliability of the device.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an insulation mounting part according to an embodiment of the present invention, Fig. 2 is a graph showing the capacitance between terminals of the insulation mounting part and jacket surge voltage characteristics, and Fig. 3 is a graph showing the insulation mounting part shown in Fig. 1. Figure 4 is a cross-sectional view of a conventional gas-insulated electrical device;
FIG. 5 is an enlarged cross-sectional view of the insulating mounting portion shown in FIG. 4, FIG. 6 is a cross-sectional view thereof, and FIG. 7 is a perspective view of the insulating collar. In the figure, (1), (2), (3) are tanks, (la), (2a), (2b), (3b) are flange parts, (1), (5) are insulating spacers, (6) is the center conductor, and (9) and (100) are insulating collars. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A cylindrical tank with a flange formed at the end;
Insulating mounting means for connecting adjacent tanks by interposing an insulating spacer between opposing flange portions, and a center conductor supported by the insulating spacer and electrically insulated from the tank by filling gas. . A gas insulated electrical device, wherein the insulating mounting means is made of a high dielectric constant material. (2) A gas insulated electrical device according to claim 1, wherein the insulating mounting means comprises bolts and nuts and an insulating collar made of a high dielectric constant material inserted between them.