JPS6235250Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to the improvement of a box-type high-voltage cut-out switch used in high-voltage distribution lines. In particular, when abnormal voltage such as multiple lightning is applied between the upper and lower electrodes of the fuse cylinder after the fuse has been cut off, This invention relates to a structure that prevents the insulator from being damaged by uneven heat due to the arc that occurs during a short-circuit accident between external poles due to external secondary flash. In high-voltage distribution lines, porcelain box-shaped high-voltage cut-out switches are used as protective equipment on the high-voltage side of pole transformers. If a large current flows due to a short circuit or the like, the large current is cut off.
However, if an abnormal voltage such as multiple lightning is applied after the interruption, the impulse voltage will be applied between the upper and lower electrodes of the fuse cylinder, causing a flashover between the external electrodes provided on the outer surface of the insulating cylinder, and will be superimposed on this secondary flashover. This may lead to a short circuit between the poles. In this case, the arc generated mainly extends to the inner surface of the lid insulator due to electromagnetic force and gets entangled with the same inner surface, eventually destroying the insulator due to uneven heat, causing the insulator to scatter, fall, etc. This could lead to a secondary public disaster. This proposal is proposed in consideration of these points. If a short circuit occurs between the outer poles of the fuse cylinder due to abnormal voltage caused by multiple lightning strikes after the fuse is blown, the arc jet that occurs will damage the inner surface of the lid insulator. A box-shaped high-pressure cutout with an insulating heat-resistant film that is resistant to heat shock adhered to its inner surface so as not to be licked directly, thereby preventing uneven heat damage to the lid insulator as described above. It is intended to provide a switch. The drawings showing the embodiments of the present application will be described below. The figure shows a conventionally known high-pressure cutout. 1 is a concave lid insulator whose lower part is pivotally attached to the main body insulator 2 via a shaft pin 3 so that it can be opened and closed; Forms a fitting protrusion 1a that can be fitted into the main insulator 2 in the closed state. Reference numeral 4 denotes a fuse cylinder, and an upper electrode 8 thereof is removably housed inside the fuse cylinder by means of an elastic piece 6 fixed by a bolt 5 and a fitting metal fitting 7 near the upper end of the inner surface of the lid insulator 1. Further, in this fuse tube 4, the above-mentioned upper electrode 8 and lower electrode 10 are provided on the outer periphery 9a of the insulating tube 9 so as to form an insulation distance L, and inside the insulating tube 9, the upper electrode 8 and the lower electrode 9 are provided. As is well known, a fuse is provided to connect the
Reference numeral 2 denotes a box-shaped main body insulator with an open bottom, and upper and lower recesses 2a and 2b are provided with slit-shaped arc extinguishing chambers 11 and 12 as well as electrodes of the fuse tube, corresponding to the upper and lower electrodes of the fuse tube. Insertion blade 8a, 1 protruding from
Upper and lower fixed electrodes 13, 1 into which 0a is inserted
4 are permanently installed. 15 is a cap for loading a fuse screwed onto the upper electrode of the fuse tube, 16 is a tightening screw for connecting the fuse lead to the lower electrode 10, and 17 is an extension of the insulating tube 9 downward, and its lower end is outside the main body. A protruding gas discharge tube, 10b, is a flange-like engagement portion integrally formed on the lower electrode 10 that engages with the side surface 12a of the lower arc extinguishing chamber fixedly installed in the main insulator;
Reference numeral 18 denotes a cushioning material, which softens the impact force applied to the arc extinguishing chamber through the engaging portion of the fuse tube when the fuse tube is pushed upward during shutoff. 19 is a wire connection terminal connected to a fixed electrode by a conductive metal fitting 20; 21 is a mounting metal fitting for a pole;
It is attached by a nut 23 to a bolt 22 fixed to the back surface 2c of the main insulator 2. Reference numeral 24 denotes an insulating heat-resistant film having heat shock resistance, which is attached to the inner surface of the recess of the lid insulator 1 between the inner surface of the recess of the lid insulator 1 and the outer surface of the fuse cylinder 4. (This is shown by a thick solid line in the drawings.) The heat-resistant film 24 is also provided on the inner surface of the main insulator 2 between the inner surface of the main insulator 2 and the outer surface of the fuse tube 4. Furthermore, these heat-resistant films 2
The application of No. 4 is carried out by a coating means. The heat-resistant film 24 is made of artificial fluorine mica in which the crystal water OH of natural mica is replaced with fluorine (compounded raw materials silica SiO ₂ , magnesia MgO, and fluoride are melted and synthesized under normal pressure and produced industrially). The main components are silicone resin and a mixture of xylene, ethyl cellosolve acetate, and other solvents. When forming the heat-resistant film 24 on the inner surface of the lid insulator and the main body insulator,
First, the inner surface, which is the surface to be painted, is cleaned and then painted to a specified thickness by brushing, spraying, dipping, etc. After painting, air dry or force dry (about 10 minutes at 60 to 100 degrees Celsius). Allow the solvent to completely evaporate. Next, it is heated and baked in a furnace at 180°C to 200°C for about 30 minutes. In this case, the solidifying agent is used in a mixture of 1 g to 100 g of the base material; however, in the case of baking at 200° C. or higher for 1 hour or more, the addition of the solidifying agent is not particularly necessary. The heat-resistant film 24 formed by baking by the above method not only has excellent electrical insulation properties due to the fluorine mica contained therein, but also has a heat resistance temperature of 600°C to 1000°C.
It exhibits sintering properties at very high temperatures of ℃, and has a hardness of about 3 to 3.5 that of aluminum, and in the painted state, the coating film contains a large amount of elastic fluorine mica. A large amount of elementary mica is applied, and in the process of solidifying the paint, the cross-sectional structure becomes layered, forming a layered structure of fluorine mica. When a large number of elastic fluorine mica forms a laminated structure, it has high impact strength and heat shock resistance.
It also has excellent adhesion and flexibility. Also, each color can be adjusted freely. In the case of the above structure, if an abnormal current such as a short circuit current flows through the high-voltage distribution line while it is being used as is well known, the above-mentioned fuse will melt and the Cut off the current. In this state, if abnormal voltage such as multiple lightning is applied from the distribution line to the upper and lower fixed electrodes 13 and 14,
The voltage is applied to the upper and lower electrodes 8 and 10 of the fuse cylinder 4. In this case, even if a secondary flash occurs between the electrodes 8 and 10, and an arc is generated by superimposing this secondary flash into a short circuit between electrodes, the presence of the heat-resistant film 24 prevents the arc from occurring. Directly licking the inner surfaces of the lid insulator 1 and the main body insulator 2 is prevented, and uneven heat damage to these insulators is prevented. Next, Table 1 shows the results of an arc resistance test when the heat-resistant film 24 was provided on the inner surfaces of the lid insulator 1 and the main body insulator 2 by the above method. In this test, a silver wire was connected between the upper and lower electrodes on the outside of the fuse cylinder to forcibly cause a short circuit between the external electrodes, and the applied voltage was 7.2KV and the current was 1.0KA~
It was conducted under the conditions of 5.0 KA and current application time of 0.2 seconds to 0.5 seconds. The results are lid insulator 1 and main body insulator 2.
No damage such as uneven heat destruction was observed on the heat-resistant film 24.
It was confirmed that the effect was significant.

[Table] As described above, in this invention, since the fuse tube 4 is electrically interposed between the upper and lower fixed electrodes 13 and 14, the upper and the lower fixed electrode 13,
When a large current flows between the terminals 14 and 14, there is a safety feature in which the current can be interrupted by cutting off the fuse. Moreover, by using the fuse tube 4 to obtain the above-mentioned safety, after the fuse is cut off as described above, abnormal voltages such as those caused by multiple lightning can be generated between the upper and lower electrodes 8 and 10 of the fuse tube 4. Even if there is a possibility that external secondary flash will occur between the electrodes 8 and 10, if the Since an insulating heat-resistant film 24 with heat shock resistance is placed between the fuse tube 4 and the inner surface of the main insulator 2, even if an external secondary flash fault occurs as described above, the arc It has the advantage of being able to prevent the lid insulator 1 or the lid insulator 1 and the main body insulator 2 from being damaged by uneven heat due to high heat. This has a safety effect that helps prevent the danger of the lid insulator 1 or both the lid insulator 1 and the main body insulator 2 being destroyed and the fragments scattering and causing harm to the public. Moreover, when the secondary flash arc occurs between the upper electrode 8 and the lower electrode 10 of the fuse tube, the heat-resistant film 2 whose internal cross-sectional structure is made of fluorine mica is laminated.
4 has an extremely high effect of blocking the heat of the arc from being transmitted to the insulator through the heat-resistant film 24, and in addition, the heat-resistant film 24 itself, which is mainly composed of fluorine mica and silicone resin, has extremely high heat resistance. It has the advantage of being able to maintain the above-mentioned heat shielding effect well because it does not burn out or burn out. These things have the effect of providing extremely high reliability in preventing uneven heat breakdown of the insulator. Furthermore, since the heat-resistant film 24 is left on the inner surface of the insulator by means of coating, it is adhered to the entire inner surface of the insulator regardless of the shape of the inner surface of the insulator, which reduces the reliability of preventing uneven heat damage. There are some features that make it even higher. Furthermore, even if the box-type high-voltage cut-out switch of the present invention is equipped with the heat-resistant film 24 as described above, if the coated part of the heat-resistant film 24 on the inner surface of the insulator becomes contaminated and a leakage current flows through it, the fluorine The heat-resistant film 24, which is mainly composed of mica and silicone resin, is nonflammable and will not be burned out by the leakage current, and has the advantage of being able to prevent a decrease in insulation resistance on the inner surface of the insulator due to burnout of the heat-resistant film 24. . Moreover, even if the membrane 24 as described above is placed between the inner surface of the lid insulator 1 and the outer surface of the fuse tube 4, the membrane 24 is farthest away from the fuse tube 4, which is the inner surface of the lid insulator 1. Since the membrane 24 is attached to a far away place, even when the fuse tube 4 is attached to and removed from the lid insulator 1, the above-mentioned membrane 24 can minimize the possibility of the fuse tube 4 coming into contact with it.
The membrane 24 can be stably positioned at the locations mentioned above, and has the effect of increasing the durability of the membrane 24. In addition, when attaching and detaching the fuse tube 4, even if the fuse tube 4 hits the membrane 24, the membrane 24 will adhere to the inner surface of a hard object called the lid insulator 1 and will not be held by that hard surface. Since it is designed to be firmly supported, it is extremely unlikely that the fuse tube 4 will be damaged due to collision, and this has the effect of contributing to the above-mentioned safety over a long period of time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a longitudinal sectional view, and FIG. 2 is a sectional view taken along the - line. 1...Lid insulator, 2...Body insulator, 13, 14
... Upper and lower fixed electrodes, 4... Fuse tube,
8, 10... Upper and lower electrodes, 24... Heat resistant film.

Claims (1)

[Scope of utility model registration request] A concave lid insulator is pivoted to a concave main body insulator in such a manner that the concave portions of both can be opposed to each other and can be opened and closed, and an upper fixed electrode and a lower fixed electrode are arranged in the concave portions of the main body insulator. On the other hand, in the recessed part of the lid insulator, there is a connection between an upper electrode and a lower electrode, which are respectively connected to the upper and lower fixed electrodes when the lid insulator is closed to the main insulator. In a box-type high-pressure cut-out switch in which a fuse tube including a fuse tube is removably installed, there is a gap between the inner surface of the cover insulator and the outer surface of the fuse tube, or between the inner surface of the cover insulator and the outer surface of the fuse tube. Between the inner surface of the main insulator and the outer surface of the fuse tube, an insulating heat-resistant film containing heat shock resistance and containing fluorine mica and silicone resin as main components is provided. The state is that the heat-resistant film is provided on the inner surface of the lid insulator or on the inner surface of the lid insulator and the inner surface of the main body insulator in a painted state and is baked in that state, and the cross-sectional structure of the heat-resistant film is , a box-shaped high-voltage cut-out switch characterized by a layered structure of fluorine mica.