JPS6024650B2 - Gas insulated telescopic busbar - Google Patents

Description

[Detailed description of the invention] The present invention relates to a telescopic busbar for gas insulated switchgear.

Gas-insulated switchgear has an arc extinguishing chamber, contacts, linear resistance elements, and other internal elements stored in a metal container filled with an insulating gas such as SF6 gas, and is used for insulation, disconnection switches, earth arresters, etc. These individual devices are connected by a gas-insulated bus bar to form a switchgear.

On the other hand, gas insulated expandable busbars are installed at important points in the connections using gas insulated busbars, which are used to adjust the dimensions for assembly and installation, to absorb thermal expansion and contraction, and to absorb dimensional fluctuations due to aging of the footing foundation. is used.

Generally, a circulating current induced by the main circuit current flows through the metal container of a gas-insulated switchgear.

This circulating current may be approximately the same magnitude as the main circuit current, and the current carrying capacity of the metal container becomes a problem. The container for the expandable bus bar is bellows-shaped and made of stainless steel, which has high electrical resistance and is thinner than metal containers used in other parts, making it undesirable as a current-carrying body. Rather, it is better not to apply current to the expandable busbar container in order to suppress the temperature rise. In order to solve this problem, the first step was to
As shown in the figure, a flexible conductor made of a highly conductive material such as copper or aluminum was attached to the outer periphery of the expandable bus bar container.

Figure 1 shows a secondary gas-insulated expandable busbar, SF6
Bellows-like sheath 1 filled with insulating gas 5 such as gas
Inside, a cylindrical conductor 2 is housed, which is insulated from the bellows-like sheath 1 by an insulating spacer 3 and fixed concentrically.

A conductor 4 is attached to the outer periphery of the bellows-shaped sheath 1 for flowing a circulating current induced by the main circuit current. Metal containers 100 and 200 are connected to both sides of the expandable busbar formed in this way. However, in this configuration, the magnetic flux due to the main circuit current interlinks with the bellows-shaped sheath, and a current is induced in the bellows-shaped sheath, so that the energization path for the circulating current becomes the metal container 100 - the bellows-shaped sheath 1 - the metal container 200.

By attaching the conductor 4 to the outer periphery of the bellows-shaped sheath 1 in this manner, it is impossible to prevent circulating current from flowing through the bellows-shaped sheath 1. Due to the principle of mirror magnetic conduction, almost no current flows through this additional conductor, and most of the circulating current flows through the bellows-shaped sheath 1. That is,
It is necessary to provide a conductor for flowing a circulating current inside the bellows-shaped sheath in the same D-shape to reduce the number of interlinkages of the magnetic flux caused by the main circuit current with the bellows-shaped sheath as much as possible.

The present invention has been made in view of this point, and it is an object of the present invention to provide a gas-insulated expandable bus bar in which an expandable conductor for circulating current is provided inside a bellows-like sheath.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIG. 2 shows an embodiment of the present invention, in which a bellows-shaped sheath 1,
It has a structure in which cylindrical slide conductors 6 and 7 through which a circulating current flows are arranged between the conductor 2, which is insulated and supported by an insulating spacer 3, in the same manner as the conductor 2. In other words, since the circulating current is passed inside the bellows-shaped sheath, the cylindrical slide conductors 6 and 7 act as magnetic shields, and the bellows-shaped sheath 1
The magnetic flux interlinking with the bellows-shaped sheath 1 is greatly reduced, and the circulating current flowing through the bellows-shaped sheath 1 is drastically reduced. Therefore, most of the circulating current flows through the metal container 100, the cylindrical slide conductor 6, the cylindrical slide conductor 7, and the metal container 200. The cylindrical slide conductors 6 and 7 each have a flange 6 on one side of the cylinder.
3 or 73, and is fixed to the bellows-shaped sheath 1 by flanges 63, 73.

The structure of the sliding contact portion of the cylindrical slide conductors 6 and 7 is as shown in FIG. That is, one cylindrical slide conductor 6
As shown in FIG. 4, a slit 62 is cut in the conductor 7, and the sliding contact portion 61 contacts the outer peripheral surface of the other cylindrical slide conductor 7 under contact pressure, thereby providing stable contact energization. It is a structure that can be used. FIGS. 5 and 6 show different embodiments of the slide conductor used in the present invention, in which the slide conductor through which a circulating current flows is configured in a dragon shape.

A cylindrical shape is ideal, but a dragon shape can also provide sufficient performance for practical purposes. These dragon-shaped slide conductors 8 and 9 have flanges 81
, 91 and sliding contact conductors 82, 92.
1 and the conductor 82, and the flange 91 and the conductor 92 are electrically and mechanically connected. The sliding contact portion of the dragon-shaped sliding conductor has the structure shown in FIG. 7, in which a finger-shaped contact 93 is incorporated into the sliding contact conductor 92 and electrically connects the sliding contact conductors 82 and 92. At the same time, the dragon-shaped slide conductor can be expanded and contracted. The Tate-shaped slide conductor is
It is fixed to the bellows-shaped sheath 1 by flanges 81 and 91. As explained above, the present invention has a conductor through which a circulating current flows inside the bellows-shaped sheath 1 and is arranged in a uniform manner so as to surround the main circuit conductor 2, so it is highly effective as a magnetic shield, and the bellows-shaped sheath Circulating current can be prevented from flowing as much as possible.

Further, since the conductor through which the circulating current flows is provided with a sliding contact portion and is made expandable and contractable, a gas-insulated expandable bus bar structure that can follow the expansion and contraction of the bellows-like sheath can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional gas-insulated expandable busbar. FIG. 2 is a sectional view of an embodiment of the gas insulated expandable busbar of the present invention. FIG. 3 is a detailed view of section A in FIG. 2. FIG. 4 is a view taken along arrow B in FIG. FIG. 5 is a sectional view of a different embodiment of the gas-insulated telescopic busbar of the present invention. FIG. 6 is a sectional view taken along arrow C in FIG. 5. FIG. 7 is a sectional view of section D in FIG. 5. Explanation of symbols, 1...
Bellows-shaped sheath, 2...Cylindrical conductor, 3...
...Insulating spacer, 4...Conductor for circulating current, 5...Insulating gas such as SF6 gas, 6,7...
...Cylindrical slide conductor, 8,9...Dragon-shaped slide conductor. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. In a gas-insulated expandable bus bar consisting of a bellows-like sheath that is freely filled with an insulating gas and a conductor that is inserted through the sheath, , a current-carrying conductor is provided surrounding this conductor for constantly passing a sheath current induced by the main circuit current of the conductor, and this current-carrying conductor slides in accordance with the expansion/contraction displacement of the bellows-shaped sheath to be in a current-carrying state. A gas-insulated telescopic bus bar characterized in that it is configured to maintain and expand/contract displacement. 2. The gas-insulated expandable busbar according to claim 1, wherein the current-carrying conductor is formed in a cylindrical cage shape.