JPS59138021A - Switching device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a solid insulation type switchgear in which a live part is molded with resin.

[Technical background of the invention and its problems]

In general, a switchgear that opens and closes an electric circuit such as a distribution line has a connection part that connects to an external electric circuit, an opening and closing part that opens and closes an electric circuit,
It has a mechanical part for opening and closing this opening/closing part. Among these, the high voltage of the electric circuit is applied to the connection part and the opening/closing part. For this reason, a solid insulation system has been adopted in which each phase and ground are insulated using a solid insulator such as epoxy resin that can withstand high voltage. That is, the space in which a switchgear is installed is generally small in many cases, and electrical equipment is required to be compact. For these reasons, the aforementioned solid insulation method, which has better dielectric strength than air insulation, has been adopted for switchgear. As mentioned above, in this solid insulation method, the area around the connection and opening/closing parts where high voltage is applied to the electric circuit is molded with solid insulation, but since the mechanical part rotates for opening and closing operations, it is molded with solid insulation. Cannot be molded with For this purpose, a space is created using a solid insulator and the mechanism is housed in this space. In other words, after storing the mechanical part in the space through the opening, this opening is closed with an insulating lid via the backing and tightened together with bolts to prevent conductive substances such as moisture from entering the space. I try not to have any.

Since such a switchgear using a solid insulation method is compact and has excellent insulation properties, it has sufficient reliability when used in a general indoor environment. However, since the urban areas where such switchgears are installed are overcrowded, the switchgear 1 is often installed in damp and dirty conditions, such as underground. When solid insulated switchgear is exposed to wet and soiled conditions, the following problems arise:

That is, when a circuit voltage is applied to the switching device and a current flows, a temperature rise occurs due to the electrical resistance of the connecting portion of the switching device and the charging portion of the switching device. This temperature increase is transmitted to the solid insulation, the air in the space, and the backing lid, and their temperatures also rise. When this temperature rise occurs, the solid insulator in which the switchgear is molded and the insulator lid soften. Also, the air pressure in the space increases. In this state, the lid is deformed by the reaction force of the backing and the increase in air pressure in the space. In other words, the insulating lid is thinner than the solid insulating material of the switchgear, so if it is used under the above-mentioned temperature rise, it will not be able to withstand the mechanical stress, and the backing reaction force will increase. The lid becomes deformed due to the increase in air pressure. When the lid is deformed, the effect of the backing on the lid disappears, creating a small gap at the interface between them, allowing free circulation of the air inside the opening/closing device space and the outside air, and removing the large amount of moisture contained in the outside air. invades the space. As a result, the air dielectric strength of the live parts in the space decreases, leading to a phase-to-phase short circuit accident. For this reason, since even a switchgear using a solid insulation type has a mechanical part, the connecting part and a part of the opening/closing part (live part) that look into the space in which it is housed are air-insulated. Therefore, sealing the space with banking and a lid is an important issue in maintaining the insulation of this live part. That is, the space can be kept sealed as long as the lid is not deformed. For this reason, lids were generally devised in terms of materials and structure.

First of all, in terms of structure, the thickness of the part where the lid is tightened with bolts is increased, and the lid is fully ribbed.

However, this method of mechanically reinforcing the lid by partially changing the wall thickness complicates the mold structure when molding the lid, and may cause the lid to warp after molding due to uneven curing shrinkage. There are technical problems such as deformation due to aging due to large residual strain. In terms of material, if a metal lid is used, there will be no deformation, but from the viewpoint of crevice corrosion of the metal, the use of metal is not preferable. For this reason, there are lids made of FRP made of resin reinforced with fibers such as glass fibers, but these lids are less likely to deform due to temperature rise, but have poor water resistance. That is, since water absorption and moisture absorption are large, when used in the above-mentioned wet and soiled state, the insulation properties are greatly reduced, causing problems in the insulation properties.

For these reasons, there has been a strong desire for a lid that is relatively thin, has uniform thickness, and is less likely to deform due to temperature rises in the live parts of the switchgear.

Further, the solid insulating portion of this type of switchgear is usually formed integrally for three phases, and the space for accommodating the mechanism portion is formed in common for the three phases.

In order to cope with the aforementioned drop in air insulation during this period, a solid insulating barrier made of resin is placed between each of these phases. Furthermore, the opening/closing mechanism section is provided with a common rotating shaft, and an insulating barrier is also provided at the penetrating portion of the shaft for the interphase insulating barrier, and this is engaged with the interphase insulating barrier to lengthen the air insulation distance between each phase. ing. However, the rotating shaft is made of metal iron. That is, if this shaft is made of an insulating material, the insulating material is easily deformed by torsional torque, so the opening/closing portion cannot be opened and closed instantaneously. For this reason, metal irons are used that do not deform due to torsional torque. The above-mentioned insulating barrier is molded onto this metal rod, and the opening/closing part is connected and fixed.
At the same time, mold the opening portion made of insulating material. That is, the shaft is made by molding an insulating barrier for preventing interphase flashover and an opening for connection with the opening/closing section with resin onto a metal rod at the same time. However, although phase-to-phase flash shorts due to deterioration of air insulation can be prevented by an insulating barrier, the air insulation to the ground between the connecting part or opening/closing part and the metal iron of the shaft is protected by the insulating barrier and does not collapse. Improvements in this respect were strongly desired as there were many flashover accidents.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid insulation type switchgear that can maintain airtightness over a long period of time for a space for storing a mechanical part, and maintains air insulation characteristics inside in a good condition. It is in.

[Summary of the invention]

The present invention relates to a solid insulation type switchgear in which a live part such as an opening/closing part is molded with a solid insulator, and a space in which a mechanical part for opening and closing the opening/closing part is housed is formed by the solid insulator. Then, a lid is attached to the opening of this space via a gasket to close the opening, and is integrally tightened with bolts, and the heat deformation temperature of the insulating resin composition constituting the lid is set to the above-mentioned temperature. The temperature is set higher than the thermal deformation temperature of the solid insulator that molds the live part to prevent deformation due to changes in the temperature and internal pressure of the lid, and to prevent moisture from entering due to this deformation.

[Embodiments of the invention]

Next, an embodiment of the present invention shown in the drawings will be described. In FIG. 1, a switching device 1 has a connecting portion 2 for connecting to an external electrical circuit, a switching section (such as a vacuum valve) 3 for opening and closing the electrical circuit, and a mechanism section 4 for opening and closing the switching section 3. Among these, the high voltage of the electric circuit is applied to the connection part 2 and the opening/closing part 3. For this reason, the connections between each phase of the connecting part 2 and the opening/closing part 3 and their grounding are integrally molded with a solid insulating material 5 such as epoxy resin that can withstand high voltage, as shown in the figure.

Further, the mechanism section 4 has a common shaft 14 for opening and closing the opening/closing section 3, and is disposed between the connecting section 2 and the opening/closing section 3. Since the mechanism part 4 makes rotational movements for opening and closing, it cannot be molded with a solid insulator 5, so a space 6 is created with the solid insulator 5 and the mechanism part 4 is housed in this space 6.

After storing the mechanism part 4 in the space 6, a cover 8 made of an insulating material is fastened to the space 6 with bolts 9 via a backing 7 to prevent conductive substances such as moisture from entering the space 6.

Here, the switchgear! , 1 are manufactured as follows.

That is, the connecting part 2 and the opening/closing part 3 are set in a mold, and the live parts such as the connecting part 2 and the opening/closing part 3 are integrally molded with a solid insulator 5 made of an epoxy resin composition by vacuum casting. In addition, the lid 8 is made using a mold different from the mold in which the live part is molded, and the epoxy resin composition is also made of the solid insulator 5 described above.
Unlike this, it is molded with an epoxy resin composition that has a higher heat distortion temperature than this. Here, the heat distortion temperature can be increased by combining a resin and a curing agent. The method for measuring the heat distortion temperature of epoxy resin compositions, etc. is AS
Compliant with TMD64B. At this time, the thermal deformation diopter of the epoxy #resin composition of the solid insulator 5 molded with the live part and the epoxy resin composition molded with the lid 8 is made higher for the lid 8. That is, when the heat distortion temperature of the epoxy resin composition is high, it is difficult to deform under load in a high temperature range and has excellent heat resistance against mechanical load. As described above, the epoxy resin composition in which the lid 8 is molded is more easily deformed by heat than the solid insulator 5 in which the live parts are molded, so the lid 8
is more difficult to deform than the solid insulator 5 even by the reaction force of the backing 7 or the increase in air pressure in the space 6. Therefore, if the solid insulator 5 deforms when electricity is applied to the live parts, the molded switchgear 1 itself will deform due to its own weight, etc., and the selection of the epoxy resin composition for molding the switchgear 1 may be incorrect. Therefore, this type of resin composition is usually selected to have a heat deformation temperature that can sufficiently withstand the temperature rise due to energization of the live parts. For this reason, as mentioned above, if the heat deformation temperature of the Evokin resin composition of the lid 8 is high, the wall thickness will be thinner than the solid insulator 5 on which the live parts are molded, and mechanical reinforcement such as a lip will not be necessary. However, deformation due to the reaction force of the banking 7 and the rise in air pressure in the space 6 can be reduced. The effect of this small deformation makes it possible to prevent air and moisture containing a large amount of moisture from flowing from the contact interface between the lid 8 and the banking 7 into the space 6.

Next, the configuration of the shaft 14, which is the main body of the mechanism section 4, is changed to a second one.
This will be explained with the help of a diagram. In the figure, 22 is a metal lot,
The outer periphery [forms an insulating layer 23 and constitutes the shaft 14. 24 is an insulating barrier which is integrally attached to the metal rod 22 by molding. Reference numeral 25 is an opening portion that is molded integrally with the metal rod 22 and is used for connection with the opening/closing portion 3 shown in FIG. This shaft 14 is made by processing a metal rod 22 into a desired shape, and then wrapping an insulating sheet made of polyester non-woven fabric soaked in resin around the outer periphery of the lot 22 on a hot plate, and heating the wound insulating sheet with a press. Pressure is applied to form an insulating layer 23 on the outer periphery. At this time, the insulating layer 23 is formed at a position such that the molded resin of the insulating barrier 24 and the opening portion 25 overlaps a portion 23a of the insulating layer 23.

If the insulating barrier 24 or the protruding part 5f is molded on the entire surface of the insulating layer 23, poor adhesion may occur at the overlapping portions, and smooth transmission of motion during opening/closing operations may occur, resulting in poor opening/closing. There is a possibility that it may occur. Therefore, as described above, the formation position of the insulating layer 3 is determined so that the insulating layer 23 and the insulating barrier 24 and the opening portion 25 are overlapped with each other so that a portion 23a thereof overlaps.

The insulating layer 23 formed at a predetermined position on the outer periphery of the metal rod 22 is set in a mold, and the insulating barrier 23 is placed in a mold.
4 and the opening part 25 are simultaneously molded with the same resin.

As shown in FIG. 1, the shaft 14 formed in this way has a conductive surface covered with an insulating material 23 even when attached to the opening/closing device 1. ) 14 and the metal rod 2 is reinforced with an insulating layer 23. In addition, the interphase insulation of the connection part 2 or the opening/closing part 3 is provided by an interphase insulation barrier (not shown) placed on the switchgear, and an insulation barrier 2 provided on the shirt 14.
Reinforced by engagement with 4. For this reason, even if moisture or water enters the space 6 and the air insulation deteriorates, the insulation between each phase and the ground insulation are sufficiently reinforced, and flash faults will occur between the phases and between the ground. Never.

As shown in FIG. 3, the lid 8 may be constructed so that the entire circumference of an FRP flat plate 10 is completely covered with a resin composition 8a having excellent moisture resistance and water resistance. In this case, the FRP flat plate 10 is positioned at the center of the encasing resin composition 8a. The thickness of the flat plate 10 is appropriately determined depending on the thickness of the lid 8, the heat deformation temperature required for the lid 8, and the moisture absorption and water absorption properties of the resin composition 8a surrounding the FRP flat plate 10.

The lid 8 of the cap octopus is manufactured as follows. In other words, a cloth whose glass fiber surface has been treated with a silane coupling agent,
After cutting to predetermined dimensions, stack the specified number of pieces on top of each other. Then, the superimposed cloth is impregnated with resin under vacuum pressure, and the resin is heated and cured to produce the flat plate 10 made of FB and P. This FRP
The flat plate 10 is processed into a predetermined shape and its entire surface is roughened. The F-P flat plate 10 processed in this way is set in a mold having the shape of the lid 8 via an insulating spacer 8b, and a resin having excellent moisture resistance and water resistance is poured into the mold by vacuum casting. The lid 8 is made by pouring the composition 8a and curing it by heating. At this time, the positioning of the FRP flat plate 10 to the center of M8 is determined by the height of the insulating spacer 8b.

In this way, the lid 8 in which the Fir flat plate 10 is embedded is significantly reinforced in terms of heat deformation temperature and mechanical strength by the glass fibers. Furthermore, since there is no glass fiber on the surface of the lid 8, it does not come into direct contact with moisture or water, so the lid 8 has excellent moisture resistance and water resistance. Therefore, even if such a lid 8 is attached to the opening/closing device 1 and a temperature rise occurs due to operation of the opening/closing device 1.

The lid 8 does not deform due to the reaction force of the backing 7 or the increase in air pressure in the space 6. Therefore, no gap is created between the lid 8 and the banking 70.

Next, the solid insulator 5 and the lid 8 that constitute the main body of the opening/closing device 1 are
An example of a backing structure between the two will be described. In other words, it is important to prevent water leakage from this rubber seal in this type of opening/closing device 1.
Although this is influenced by the deterioration of the rubber seal, it is mainly influenced by the tightening structure of the rubber seal. That is, when tightening the rubber seal, the tightening torque is limited by the mechanical strength of the lid 8, the tightening bolt 9, etc., and therefore remains constant regardless of the area of the rubber seal. For this reason, if you use hard rubber gaskets to increase the contact surface pressure,
If the tightening torque is limited as described above, the lid 8 will not be tightened enough. Also, if the hardness of the rubber seal used is low, water leakage may occur due to insufficient contact surface pressure.

For this reason, in order to eliminate insufficient tightening of the lid 8, a rubber seal structure is desired that uses a rubber seal with low hardness and prevents water from leaking even if the contact surface pressure is insufficient. .

In the embodiment shown in FIG. 4, a groove 34 having a radius of curvature larger than the radius of the rubber seal 7 is provided in the seal contact portion 2 between the lid 8 and the solid insulator 5 on the main body side. These grooves 3
Insert the rubber gasket 7 into 4 and tighten. As a result, the rubber packing 7 is crushed on the entire surface of the groove 34, and the groove 34 is crushed.
Pressure acts evenly on the entire surface. Further, since the rubber gasket 7 contacts in an arc shape, the contact length becomes long, and water leakage at the interfaces between the lid 8 and the solid insulator 5 and the rubber gasket 7 can be prevented.

The embodiment shown in FIG. 5 is a partially modified version of the one shown in FIG. 4, and the structure on the lid 8 side is the same as that in FIG. 3. On the other hand, a groove 35 having approximately the same radius as the rubber packing 7 is provided on the solid insulator 5 side, and a recess 36 is formed at the bottom of the groove 35, and an adsorbent 37 such as silica gel is placed in the recess 36. ing. In this way, the contact surface pressure between the lid 8 and the rubber gasket 7 is equal and the contact length is long, so that water leakage can be prevented. Furthermore, on the solid insulator 5 side, the contact length at the interface of the rubber packing 7 is short, but since the adsorbent 37 is inserted in the middle, even if there is some water leakage,
This can be completely removed by adsorption with an adsorbent.

In the embodiment shown in FIG. 6, two packing grooves 44 are formed in parallel in the packing contact portion of the solid insulator 5 on the main body side so that multiple rubber packings 7 can be arranged in parallel. A recess 45 is provided between the two, and the adsorbent 37 is placed in the recess 45. In this way, even if the hardness of the rubber gasket 7 is lowered and the contact surface pressure with the lid 8 is reduced, water leakage from the outside will be absorbed by the adsorbent 37 placed between the rubber gaskets 8, so that the air between the rubber gaskets 8 will be absorbed. Moisture is removed, and moisture does not leak into the live parts or mechanical parts of the device, and problems such as poor insulation and corrosion do not occur. Further, since the rubber packing 7 has a low hardness, a sufficient tightening effect can be obtained even with the tightening torque limited by the mechanical strength of the lid 8 or the tightening bolt.

[Effects of the Invention J As described above, according to the present invention, it is possible to effectively prevent moisture from entering the internal space of a solid-insulated switchgear, and to maintain the air insulation properties in this space effectively. keep it in good condition. Therefore, flashovers and the like due to poor air insulation in this space can be effectively prevented for a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of a solid insulation type switchgear according to the present invention, and Fig. 2 is a side sectional view showing an embodiment of the solid insulation type switchgear according to the present invention. 3 is a side sectional view showing another embodiment of the present invention, and FIGS. 4, 5, and 6 are backing portions in other embodiments of the present invention. FIG. 1... Opening/closing device 3... Opening/closing part 4°°°
゛ Mechanical part 5... Solid insulator 6 for molding the live part...
・Space 7・・・Packing 8・・・Lid
8a・Resin composition 9・・・・tightening pole)
10...F 几P flat plate 14... Shaft 22・Yanganeme rod 23...Insulating layer
25... Meddling Department (7317) Agent
Patent Attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (3)

[Claims] (1) In a solid insulation type switchgear in which a live part such as an opening/closing part is molded with a solid insulator, a space in which a mechanical part for opening/closing the opening/closing part is housed is formed by the solid insulator; A lid is attached to the opening of the space via a gasket to close the opening, and is integrally tightened with bolts. A switchgear characterized in that the temperature is set higher than the thermal deformation temperature of the solid insulator to be molded. (2) The opening/closing device according to claim 1, characterized in that the lid is a flat plate made of FRP whose entire surface is covered with a resin composition having excellent moisture resistance and water resistance. (3) As a mechanism part, at a predetermined location on the outer periphery of the metal iron,
Claims 1 and 2 are characterized in that the sunshade part for connection with the opening/closing part is integrally attached by molding, and has a shaft with an insulating layer formed on the other outer peripheral surface. Switchgear as described in Section.