JPH04334912A - Switchgear for main circuit - Google Patents

Abstract

PURPOSE:To obtain a highly economical switchgear which enhances reliability and makes maintenance work unnecessary by keeping inside of housing under low humidity and clean condition and also by avoiding dielectric breakdown resulting from dewing. CONSTITUTION:An insulated space 22 is formed by an insulating and air-tight sealing portions 30 provided in both sides of a circuit switchgear means 7 housed within a cylindrical housing and the housing itself. Moreover a pressure adjusting means 31 which is connected to such insulated space and can dehumidify the space is also provided. A switchgear ensures that the internal insulated space 22 is never opened to external atmosphere, even under the high humidity environment, through the housing 9 of the switchgear, insulating and air-tight sealing portions 30 and insulator oil of pressure adjusting means 31. In addition, even when temperature of internal insulated space 22 changes depending on ambient temperature, under the outdoor environment showing large change of ambient temperature, and a pressure of the insulated space 22 also changes depending on such temperature change, two oil levels of pressure adjusting means 31 automatically change to supply external air and eliminate a difference between internal and external pressures.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main circuit switchgear used in power plants and the like, in which a bus bar is housed within a jacket.

0002

2. Description of the Related Art FIG. 5 is a sectional view showing a circuit breaker as an example of conventional main circuit switching devices disclosed in, for example, Japanese Utility Model Application No. 51-34666 and Japanese Utility Model Application No. 58-166213. . In the figure, 1 is a breaker, 2 is an insulating tube that houses the breaker 1, 3 and 4 are energizing tanks connected to the insulating tube 2, and 5 and 6 are circuit breaker terminals attached to the energizing tanks 3 and 4, respectively. , 8 is a supporting insulator that supports the energizing tanks 3 and 4, 9 is an outer cover that closes the live parts of the energizing tanks 3, 4, etc. at a predetermined air insulation distance from the live parts, and 10 is an operating mechanism. Yes, these 1 to 6 and 1
0 constitutes a circuit opening/closing means. Further, reference numerals 11 and 12 denote phase separation busbars connected to both sides of the circuit opening/closing means 7, each of which is composed of a conductor 14 provided with a terminal 13, a support insulator 15 supporting the conductor 14, and a jacket 16. ing. Note that the circuit breaker terminals 5 and 6 are connected to the phase separation bus bar 11 by flexible conductors 17 that absorb thermal expansion and contraction.
and 12, and the jacket 9 is also connected to the jacket 16 of the phase separation bus.

Next, the operation etc. will be explained. Operation command (
The operation mechanism 10 automatically operates according to the signal), and this operation is mechanically transmitted to the interrupting part 1 via links and levers (not shown) provided in the internal space of the support insulator 8, etc. , the opening or closing operation of the interrupter 1 is achieved. At this time, a large impact force is usually applied to the insulating tube 2 and supporting insulator 8, so in order to have a structure that can withstand this force, the insulating tube 2 and supporting insulator 8 are made of epoxy resin, etc. Specially shaped cast insulators made from organic insulators are used. On the other hand, almost no external force is normally applied to the support insulators 15 of the phase separation buses 11 and 12, and for this reason, general porcelain insulators with excellent insulation performance are used. That is, it not only has excellent withstand voltage characteristics at normal humidity, but also a drain pipe (not shown) provided on the outer sheath 16 of the phase separation bus.
Outside air may enter through the openings of the phase separation bus, and leakage of outside air may occur at seals such as gaskets installed at the inspection cover (not shown) of the phase separation bus bar and connections with other equipment. Even when the inside of the separation bus bar is in a high humidity state where dew condensation occurs, the support insulator 15 hardly absorbs water or moisture, and the withstand voltage performance does not deteriorate. In addition, in such a dew condensation environment, the insulation resistance decreases on the creeping surface of the supporting insulator 15, and creeping partial discharge may occur, but since the material is an inorganic material called porcelain and has excellent heat resistance, No deterioration of the support insulator 15 occurs, and there is no change in the withstand voltage characteristics of the support insulator 15 itself. On the other hand, in the insulating cylinder 2 and supporting insulator 8, moisture easily permeates through the insulating resin material by diffusion.
It is recognized that withstand voltage performance decreases due to dew condensation, etc., and if creeping partial discharge occurs, a partial deterioration called tracking occurs due to carbonization as a fate of organic matter, resulting in a type of insulation deterioration.

0004

[Problems to be Solved by the Invention] Since the conventional main circuit switchgear is constructed as described above, it cannot be used in a high humidity environment.
In places where condensation is likely to occur internally, such as in outdoor environments where there are significant changes in ambient temperature, there is a strong possibility that ground faults will occur due to insulation breakdown. Therefore, there was a problem in that the layout design of the power generation main circuit equipment was extremely restricted. Furthermore, even when installed indoors, anti-tracking paint is generally applied to the surface of the cast insulator such as the insulating cylinder 2 in case of condensation, which makes the cast insulator expensive. was there. Furthermore, there have been other examples of devices such as the disconnector disclosed in JP-A No. 62-141908, in which a type of dry air is constantly supplied into the disconnector to maintain the interior at low humidity. In this case, it cannot be applied if the circuit breaker is an electric spring operated type or a hydraulically operated type, and even if it is an air operated type circuit breaker as in the example in the above publication, compressed air is generated because air is constantly supplied to the disconnector. The operation of the device is continuous, which is uneconomical, and requires frequent maintenance and inspection, which has many disadvantages.

[0005] This invention was made in order to solve the above-mentioned problems, and is a highly reliable main body that maintains the interior at low humidity and cleanliness under any environment and does not cause dielectric breakdown due to condensation. The purpose of the present invention is to provide a main circuit switchgear that is highly economical because it does not require a power-driven machine such as a compressed air generator, and requires almost no maintenance and inspection work. do.

[0006]

[Means for Solving the Problems] A main circuit switching device according to the present invention includes a circuit switching means for opening and closing a conductive circuit provided between bus conductors housed in a cylindrical jacket, and a circuit switching device for opening and closing a conductive circuit. A support insulator that carries the means within the jacket, and two sets of insulating hermetic sealing parts located on both sides of the circuit opening/closing means in the longitudinal direction of the jacket and sealing the inside of the jacket with an insulating material are provided. The formed insulating space and the container hold a moisture absorbent, the upper part communicates with the insulating space, the lower part is U-shaped, one side is open to the atmosphere, and the U
The pressure adjusting means is formed by immersing insulating oil so as to form two liquid levels in the character-shaped portion.

[0007]

[Function] Even in a high humidity environment, the main circuit switchgear of the present invention maintains the internal insulating space from the external atmosphere due to the outer sheath of the device, the insulating hermetic seal, and the insulating oil of the pressure regulating means. There is no direct contact, and in an outdoor environment where the ambient temperature changes significantly, the temperature of the internal insulated space changes depending on the ambient temperature, and the pressure in the insulated space changes accordingly. The two oil level heights of the adjusting means are automatically changed to supply external air and eliminate the pressure difference between the inside and outside.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIG. In addition, in the drawings, the same reference numerals as in the conventional example indicate the same or corresponding parts, and the explanation thereof will be omitted. In FIG. 1, 18 is a flange welded to the inside of each outer sheath 16 of the phase separation bus bars 11 and 12 connected to the circuit opening/closing means 7 and the outer sheath 9 on both sides in the longitudinal direction. The configured mounting flange 20 is attached with bolts or the like. Reference numeral 21 denotes a ring-shaped gasket that seals the gap between the conductor 14 and the insulator tube 19 passing through the inside of each porcelain insulator tube 19, and similar to FIG. In the vicinity of both sides of the circuit opening/closing means 7, an insulating hermetic sealing portion 30 is formed. Reference numeral 22 denotes an insulating space surrounded by the insulating hermetic sealing portions 30 on both sides of the circuit opening/closing means 7, a part of each outer sheath 16 of the phase separation buses 11 and 12, and the outer sheath 9 of the circuit opening/closing means 7.

FIG. 2-A is an enlarged cross-sectional view showing details of a portion in FIG. A connection pipe 26 has both ends connected to the container 23 and the outer sheath 9 so as to communicate with the container 2
3, a U-shaped tube whose one end is connected to the container 23 at an end position opposite to the connecting end of the connecting pipe 25, and 27, a predetermined amount of oil is injected into the U-shaped tube 26 so as to form two oil levels. The insulating oil 28 is a dustproof filter provided in the middle of the path inside the U-shaped tube 26, and these 23 to 28 form a pressure regulating means 31. In the figure, a wire mesh or the like (not shown) is provided at the opening connection between the container 23 and the U-shaped tube 26 to prevent the moisture absorbent 24 from coming out of the container 23.

Next, the operation will be explained. The insulating space 22 shown in FIG. 1 is formed by an insulating gas sealing part 30 made of a porcelain insulator tube 19, etc. on both sides of the circuit opening/closing means 7 in the longitudinal direction, an outer sheath 9, an insulating oil 27 in the U-shaped tube 26, etc. ,
Since it is not in direct contact with the external atmosphere at all times, it is not directly affected by external humidity. Furthermore, when the configuration shown in FIG. 1 is installed outdoors where the influence of solar radiant heat and changes in ambient temperature are significant, the temperature in the insulated space 22 will change in response to changes in the conditions of the outdoor environment. Since the pressure in the insulating space 22 changes according to Boyle-Charles' law, for example, at the connecting flange portion between the outer jacket 9 and 16, or at the connecting portion between the flange 18 and the mounting flange 20, the pressure between the external atmosphere and the insulating space 22 changes. Air leakage is about to occur. At this time, oil level displacement occurs within the U-shaped tube 26 at the same time, and the pressure between the insulating space 22 and the external atmosphere is balanced by the air supply or exhaust action through the U-shaped tube 26, thereby preventing the air leakage. It turns out. That is, due to, for example, a drop in ambient temperature, a decrease in solar radiation, or sudden rainfall, the insulating space 22
When the temperature starts to drop and the pressure begins to drop, the left and right oil levels in the U-shaped tube 26 shift in conjunction with each other due to this slight pressure difference, and as shown in Figure 2-B, the oil level on the outside atmosphere side changes. reaches the bottom of the U-shaped tube 26. After that, external air is taken in from this oil level position, rises in the form of air bubbles 29 in the insulating oil 27, is dehumidified by the moisture absorbent 24 as it passes through the container 23, and finally is insulated from the connecting pipe 25. space 2
Air is supplied to the insulating space 22, and the pressure between the insulating space 22 and the external atmosphere is balanced. In addition, external air is filtered through filter 28 and insulating oil 2.
7 removes dust, so only clean, dry air is required in the insulating space 22.

[0011] Conversely, due to changes in the outdoor environment,
When the temperature in the insulating space 22 rises, the oil level shown in FIG. 2-B is reversed and the oil is exhausted from the insulating space 22 to the outside. In this way, even in an outdoor environment, the configuration shown in FIG. Since dehumidification and dust removal are performed, the insulating space 22 can always be maintained at low humidity and cleanliness. In addition, the moisture absorbent 24 such as silica gel becomes saturated with moisture absorption over time in the application state as described above, but it can be easily replaced with a new moisture absorbent by removing the container 23.

Example 2. In the first embodiment, a predetermined amount of insulating oil 27 is filled in the U-shaped tube, but as shown in FIG. Using the oil pot 33 which is arranged as shown in FIG. An oil surface may be formed in each of the pipes 33 to constitute a communication device having the same function as the U-shaped pipe, and the same effect as in the above embodiment can be obtained. FIG. 3-B shows how the configuration of FIG. 3-A draws air from the external atmosphere.

Example 3. In addition, in the above-mentioned Example 1, an insulating airtight sealing portion using a porcelain insulator is provided inside the phase separation bus bar connected to the circuit switching means in the vicinity of both sides in the longitudinal direction of the circuit switching means. As shown in FIG. 4, even if flanges 9a are provided on both sides of the jacket 9 of the circuit opening/closing means 7 to form an insulating hermetic seal through which the energizing tanks 3a and 4a penetrate, the same result as in the above embodiment can be obtained. be effective. Further, in the first embodiment, a circuit breaker is used as the circuit opening/closing means, but it may be a disconnector, a grounding device, or a combination thereof.

[0014]

Effects of the Invention As described above, the present invention includes a circuit opening/closing means for opening and closing a conductive circuit provided between bus conductors housed in a cylindrical jacket, and a circuit opening/closing means for opening/closing a conductive circuit within the jacket. A support insulator to be supported, and two sets of insulating hermetic sealing parts located on both sides of the circuit opening/closing means in the longitudinal direction within the jacket and sealing the inside of the jacket with an insulating material are provided. An insulated space and a moisture-absorbing material are held in the container, the upper part communicates with the insulated space, the lower part is U-shaped, and one side is open to the atmosphere, and
By configuring the U-shaped part with a pressure regulating means formed by dipping insulating oil to form two liquid levels, the inside of the outer jacket can be kept low in humidity and clean in any environment. In addition to increasing reliability as dielectric breakdown due to condensation and the like does not occur, there is no need for maintenance and inspection work, which has the effect of providing an economical main circuit switchgear.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 shows details of the pressure regulating means in FIG. 1, with A being an enlarged cross-sectional view thereof and B being a cross-sectional view during its operation.

FIG. 3 shows a pressure regulating means in Embodiment 2 of the present invention, in which A is a detailed sectional view thereof and B is a sectional view during its operation.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional main circuit switchgear.

[Explanation of symbols]

7 Circuit opening/closing means 8 Support insulator 9. Outer covering 11 Bus line 12 Bus line 22 Insulation space 30　Insulating hermetic sealing part 31 Pressure adjustment means

Claims (1)

[Claims] 1. A circuit opening/closing means for opening and closing a conductive circuit provided between bus conductors housed in a cylindrical jacket, a support insulator supporting the opening/closing means within the jacket, and a support insulator for supporting the opening/closing means within the jacket; There are two sets of insulating hermetic sealing parts located on both sides of the circuit opening/closing means in the longitudinal direction of the housing and sealing the inside of the jacket with an insulating material. pressure regulating means having an upper portion communicating with the insulating space and a lower portion having a U-shape with one side open to the atmosphere, and immersing insulating oil in the U-shaped portion to form two liquid levels. A main circuit switchgear characterized by comprising: