JPH0787652B2 - Gas insulated switchgear - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas insulated switchgear that can be used in extremely cold regions.

[Conventional technology]

FIG. 6 shows, for example, Mitsubishi Electric Technical Report Vol. 47, No. 9 (Sho 4
8) is a partial cross-sectional side view of the conventional gas-insulated switchgear shown on page 971. (1) is a circuit breaker, (2) is a disconnector, (3) is another type of disconnector, (4) is a grounding device,
(5) is a bus bar, (6) is a cable head part, (7) is a cable, (8) is a current transformer, and (9) is a connection part. Although each device is a single-phase type, only the bus bar (5) is shown as an example of a three-phase type. The charging part of each device is supported by an insulating spacer (10) and an insulating support base (11). Insulating spacer (10) between the conductors are made airtight, while others serve to divide the interior of the gas, for example, breaker only 5Kg / cm ² -g, other devices 4 Kg / cm ² - It is also possible to set the gas pressure to g or fill with another gas. A sliding contact (12) is used for the energizing part and the opening / closing part to energize and open / close to facilitate the assembly. Also, the container (13) of each device is made airtight, and the inside (A), (B), (C), (D), (E), (F), etc. are filled with 4 to 5 kg / cm ² -g of SF6 gas. It is used as an insulating medium and an arc extinguishing medium for switchgear.

Such, the gas insulated switchgear, compared with the conventional apparatus air insulation, the insulation distance by the use of SF ₆ was soo are the insulation performance is reduced by a large margin, it is compact and lightweight, in the arc extinguishing performance The excellent SF ₆ also improves the circuit breaker performance. Furthermore, since the charging section is inside the container, high reliability is obtained without being affected by the outside.

[Problems to be solved by the invention]

However, the conventional gas-insulated switchgear has 4-5 kg / g in the container.
Since SF ₆ gas with a pressure of cm ² -g was used, -50 ° C
For gas-insulated switchgear used in extremely cold regions, such as SF
There was a problem that the ₆ gas was liquefied and accumulated in the lower part of the container, the density of SF ₆ gas as an insulating medium and an arc extinguishing medium decreased, and the dielectric strength of each device and the breaking ability of the switchgear decreased.

The present invention has been made to solve the above problems, and an object thereof is to obtain a gas insulated switchgear that can be used even in an extremely cold region such as -50 ° C.

[Means for solving problems]

In the gas insulated switchgear according to the present invention, the circuit breaker is pressurized.
A structure for heating or kept warm SF ₆ gas, equipment other than circuit breakers, the N ₂ gas was mixed in SF _6, enclosed so that the partial pressure of SF ₆ gas becomes less saturation pressure of the lowest operating temperature, this The insulation design is performed according to the dielectric strength of the mixed gas.

[Action]

In the gas-insulated switchgear according to the present invention, since the circuit breaker does not liquefy even at low temperatures, the gas in the arc extinguishing section has the same density as at normal temperature and has sufficient breaking performance, and other equipment does not liquefy and has the same temperature as normal temperature. The density can be maintained and sufficient insulation performance can be maintained.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. First
The figure is a partial cross-sectional side view of a gas-insulated switchgear in which the same devices as in FIG. 6 are connected in the same manner. Devices and parts having the same symbols as in FIG. 6 have the same names and perform the same functions. In the figure, (14) is a connection part, (15) is a heat insulating cover, (15a) (15b) (15c)
(15d) is a vent for opening and closing the heat insulating cover, (15e) is a heat insulating material, and (16) is a heater. Further, FIG. 2 is a detailed sectional side view of the circuit breaker (1) and its vicinity shown in FIG. 1, and FIG. 3 is a sectional view of the circuit breaker seen from above.

The conditions of use to -50 ° C. In this example, circuit breaker (1) of the inner (A) to the SF ₆ gas 5Kg / cm ₂ -g (at 20 ° C.)
Fill. This pressure is the same as for warm regions. In the other parts (B) (C) (D) (E) (F) (G), SF
₆ gas was mixed with 3.0 kg / cm ₂ -a and nitrogen gas was mixed with ₂ kg / cm ₂ -a (converted to the value at 20 ° C.).

As shown in FIG. 4, the temperature-pressure-density relationship of SF ₆ gas is, for example, SF ₆ gas sealed at 5 Kg / cm ₂ -g at 20 ° C. begins to liquefy at −33 ° C. The gas enclosed at ₂ Kg / cm ₂ -g starts to liquefy at -52 ° C.

In the above example of the present invention, when the temperature reaches about 0 ° C, the ventilation holes (15a) (15b) (15c) (15d) of the heat insulating cover (15)
However, for example, by using a shape memory alloy, it has a structure that opens and closes.
When the temperature reaches ℃, an electric current starts to flow through the heater (16) by the thermostat, and the breaking wire is heated. Since the capacity of the heater is such that the circuit breaker gas does not liquefy even at the lowest temperature of the place of use, the circuit breaker (1) does not liquefy in any case, and good circuit breaking performance can be maintained.

On the other hand, when the temperature is high, the ventilation port (15a) of the protective cover (15)
(15b) (15c) (15d) open, the outside air is taken in from the lower part and discharged from the upper part, and the circuit breaker container (13) is cooled.
Heat is sufficiently dissipated to correspond to the heat generated by energization, and there is no reduction in energizing ability.

In the above example, since the vent holes are arranged above and below, the flow of outside air is good due to the chimney effect of the protective cover (15).
Further, since the heater (15) is supported and protruded from the container (13) by a good conductor, the heater (15) functions as a heat radiating fin to perform good cooling.

Gas (B) (C) (D) (E) of equipment other than circuit breakers
(F) and (G) show that SF ₆ gas is 3.0 kg / cm ² -a in the above example.
Is a mixed gas of SF ₆ 60%, the liquefaction is -52 ° C.
Liquefaction does not occur when used up to -50 ° C. Therefore, the SF ₆ gas is kept at the same density as at room temperature, and the insulation characteristics are maintained at room temperature.

The relationship between the ratio of SF ₆ in the mixed gas of SF ₆ and nitrogen gas and the dielectric strength is as shown in Fig. 5, and the mixed gas of SF ₆ 60% is about 90% of the dielectric strength of SF ₆ 100%. Since it only decreases, the insulation distance of the device, that is, the increase in the size of the device, is 10%
There is little cost up below.

On the other hand, as in the relationship between the mixing ratio of interruption performance and SF ₆ gas, there is a test example of the breaking current in SF ₆ 75% to about 90%, it decreases to about 60% SF ₆ 50% SF ₆ When the gas ratio changes, the breaking performance changes greatly in proportion to the SF ₆ ratio. Therefore, when the same gas as that of other equipment is used, the gas pressure is lowered and the breaking performance is reduced to about half that at room temperature. Also, in order to make a circuit breaker having the same capacity, a large and expensive circuit breaker having a capacity nearly double at room temperature is required. However, in the present invention, a heater is inserted only in cold weather so that it can be used at room temperature. It is economical because the circuit breaker can be used.

It should be noted that, as in the example of FIG. 1, it is preferable that the connection portions (9) and (9a) adjacent to the circuit breaker (1) also have a heat insulating cover (15) and a heater (16). By doing so, it is possible to prevent the temperature of the insulating spacer (10) of the circuit breaker (1) from decreasing due to the cooling from the connecting portions (9) and (9a) and causing local liquefaction.

In addition, the sliding contact (12) is attached to the conductor of the connecting portion (9) (9a).
Should be provided. In addition to being convenient for assembly, because of point contact,
The amount of heat transfer is small, and heat can be transmitted through the conductor to reduce heat intrusion.

〔The invention's effect〕

As described above, according to the present invention, a circuit breaker having a large influence of gas pressure on arc extinguishing performance has the same 10
Fill with 0% SF ₆ gas and keep it warm in cold weather to prevent liquefaction,
Other devices become SF ₆ partial pressure of not only liquefied during cold SF ₆
And so was filled with mixed gas of N _2, it can be fabricated available cold regions for gas insulated switchgear in the land of frigid as that -50 ° C..

[Brief description of drawings]

FIG. 1 is a sectional side view showing a gas insulated switchgear according to an embodiment of the present invention, FIG. 2 is a sectional side view of a circuit breaker portion thereof, FIG. 3 is a sectional plan view of the circuit breaker thereof, and FIG. Fig. 5 is a liquefaction characteristic diagram of SF ₆ gas, Fig. 5 is an insulation characteristic diagram of SF ₆ -N ₂ mixed gas, and Fig. 6 is a sectional side view of a conventional gas insulated switchgear. In the figure, (1) is a circuit breaker, (2) and (3) are disconnectors,
(4) is a grounding device, (15a) (15b) (15c) (15d) is a heat retaining cover, and (16) is a heater. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (5)

[Claims] 1. A circuit breaker and a plurality of accessory devices, a first container for sealing gas and housing the circuit breaker, and a plurality of second containers for sealing gas and housing the accessory device. In the gas insulated switchgear, the gas in the first container is 2K
and g / cm ² -g (at 20 ° C.) or higher of SF ₆ gas, the gas in the second vessel partial pressure 2Kg / cm ² -g (at 20 ° C.)
SF ₆ gas and nitrogen gas are mixed to obtain a total pressure of 2 kg / cm ² −g
The above mixed gas (at 20 ° C.) is used, and the second container and the first container, which are arranged adjacent to the first container in the second container, are kept warm by a heat keeping means. And gas insulated switchgear. 2. The gas-insulated switchgear according to claim 1, wherein the heat retaining means is a cover surrounding each of the containers with a predetermined distance therebetween. 3. The cover according to claim 2, wherein the cover is provided with a vent hole that is opened at a predetermined temperature.
The gas-insulated switchgear according to the item. 4. A circuit breaker and a plurality of accessories, a first container for sealing a gas and housing the circuit breaker, and a plurality of second containers for sealing a gas and housing the accessory. In the gas insulated switchgear, the gas in the first container is 2K
and g / cm ² -g (at 20 ° C.) or higher of SF ₆ gas, the gas in the second vessel partial pressure 2Kg / cm ² -g (at 20 ° C.)
SF ₆ gas and nitrogen gas are mixed to obtain a total pressure of 2 kg / cm ² −g
A mixed gas of the above (at 20 ° C.) and the second container and the first container, which are arranged adjacent to the first container in the second container, are surrounded by a cover, and in the cover. A plate-shaped heating heater disposed in the outer surface of the first container and the outer surface of the second container adjacent to the first container in a heat conductive manner so as to be planted in the width direction. Characteristic gas-insulated switchgear. 5. The gas-insulated switchgear according to claim 4, wherein the heaters are arranged in a vertical direction in a longitudinal direction and are spaced apart from each other by a predetermined distance.