JP5537229B2 - Wind noise prevention - Google Patents

Description

  The present invention relates to a solid insulator in which a large number of shades are formed at a constant pitch on the outer periphery of the trunk, and more particularly to a wind noise-preventive solid insulator in which the shade shape is devised so as not to cause an unpleasant wind noise during strong winds. Is.

  Solid support insulators such as SP (station post) insulators and LP (line post) insulators are widely used to insulate and support electrical equipment in substations and to insulate and support jumper wires on power transmission towers. It has been. These solid insulators have a large number of shades formed at a constant pitch on the outer periphery of the trunk to ensure a surface leakage distance.

  Among these solid insulators, those used for heavy pollution areas and direct current transmission require a long surface leakage distance as the insulation strength decreases, and the shape of the shade has a structure in which multiple ribs are formed on the back surface. It has become. Also, in the snowfall area, if snow falls between the shade pitches and the shade between the top and bottom shades is continuous with snow, the surface leakage distance cannot be secured and the insulation strength decreases, causing a short circuit accident. There is a fear. In order to prevent such snow damage, there is a solid insulator for snowfall areas that makes it harder to snow by increasing the pitch between the shades. Use a shade shape similar to that for districts and DC power transmission. The angle of inclination of the upper surface of these shades is increased from about 10 degrees for general shades to about 25 degrees so that dirt and snow can easily slide off. However, in the case of such a heavy and snowy damage, the solid coconut sometimes produces annoying wind noise in strong winds, and there may be complaints from residents when there is a private house near the installation location. . On the other hand, there are almost no complaints about the general Nakako.

  Note that wind noise may also be a problem with the hanging insulator, and Patent Document 1 and Patent Document 2 show measures for improvement. Each of these hanging insulators has the longest rib at the tip of the shade to prevent the wind hitting the shade from reaching the space between the inner ribs, and the vibration of the insulator due to Karman vortices generated in this space. Is suppressed. However, unlike the press-molded suspension insulator, the solid insulator is manufactured by a method of shaving the cap shape with a cutting tool while rotating a cylindrical material, so that deep ribs such as Patent Document 1 and Patent Document 2 are formed. It is not easy to install at the tip of the shade.

  In addition, the suspension insulators are flexibly connected to each other, so only the vibrations of the individual insulators are a problem. However, since the solid insulators are integrated as a whole, the vibrations of the shades resonate. May grow. Therefore, the wind noise prevention measure for the suspended insulator cannot be used as it is, and the wind noise prevention measure for the solid insulator has been hardly studied.

Japanese Patent Publication No. 4-101261 JP 2003-31062 A

  Therefore, the object of the present invention is to solve the above-mentioned conventional problems, and even when the shade pitch is widened to prevent snow damage, wind noise with a shade shape devised so as not to cause harsh wind noise during strong winds. The prevention is to provide a real eggplant.

  In order to solve this problem, the present inventor is capable of mass production, has an effect of preventing snow damage, satisfies electrical characteristics such as a surface leakage distance, has the same overall length and outer diameter as the standard product, and has a strong wind. A lot of prototypes were made in search of a shade shape that can suppress unpleasant wind noise in the wind tunnel, and wind noise was measured by applying wind at various wind speeds through wind tunnel experiments. As a result, the Karman vortex generated by the wind caught between the ribs is the main cause of the wind noise, but it is the same as the suspension insulator, but the longest rib is formed at the tip of the shade like the suspension insulator. Instead, in solid insulators, it is effective to form a recess for guide that deflects the wind hitting the shade downward at the tip of the shade, and in solid insulators to suppress resonance between multiple shades that are an integral structure In addition, we have found that it is more effective to thicken the shade than the standard product.

The present invention has been completed based on such knowledge, and is a solid insulator in which a plurality of shades with a plurality of ribs suspended from the back surface are formed at a constant pitch on the outer periphery of the trunk portion. Is the maximum thickness obtained from the curvature radius R = {(shade angle line length W / 2) ² + thickness T ² } / (2 × thickness T) mm from 5 mm to 10 mm on the shade angle line. It has a thick shape with a curvature and is expanded upward, and the ribs on the outermost circumference of each shade are drooped more than the other ribs, and they are placed at a position retracted inward from the tip of the shade to hit the shade. A guide concave portion for deflecting the wind downward on the outer peripheral surface of the outermost rib is formed.

As in claim 2, it is preferable that the shapes of the shades are the same. In the following description, “thickness” and “thickness T” mean an increase in thickness due to the upper surface of the shade being inflated with a curvature, not an absolute value of the thickness. Absent.

  The wind noise preventing solid insulator of the present invention has a curvature on the upper surface of each shade and is inflated upward so as to have a thicker shape than the standard product, so that the stiffness of the shade is increased and vibration is suppressed. In addition, by having an appropriate curvature, the top surface of the shade is streamlined and the wind can easily pass through, and the shade vibration is suppressed. In addition, the outermost rib of each shade is drooped more greatly than the other ribs, and is provided at a position retracted inward from the tip of the shade, thereby diverting the wind hitting the shade downward on the outer circumference of the outermost rib. By forming the guide recess, the wind is less likely to be caught between the ribs, and an annoying wind noise due to Karman vortex is suppressed.

  In this way, even when the shade pitch is widened to prevent snow damage, wind noise can be prevented by changing the shade shape slightly, so there is an effect of preventing snow damage, such as surface leakage distance. It is possible to provide a wind noise-preventing solid insulator that satisfies general characteristics and has the same overall length and outer diameter as standard products.

As in the first aspect, an excellent wind noise prevention effect can be obtained by drooping the outermost rib of each shade larger than the other ribs. Moreover, the effect of increasing the thickness of the shade is enhanced by setting the thickness (increased thickness) on the shade angle line of each shade from 5 mm to 10 mm on the shade angle line. Furthermore, by making the shape of each shade the same as in claim 2 , it becomes possible to easily manufacture a solid insulator that is homogeneous over its entire length.

1 is an overall front view showing an embodiment of the present invention. It is an expanded sectional view of a shade shape. It is an expanded sectional view of the shade shape of the existing solid insulator for snow damage prevention. It is explanatory drawing of the effect of this invention. It is explanatory drawing of a wind tunnel experiment. It is a graph explaining "excellence". It is explanatory drawing of the maximum wall thickness and curvature radius of a cap upper surface.

The present invention is described in further detail below.
FIG. 1 is an overall front view showing an embodiment of the present invention, wherein 1 is a solid cylindrical body made of porcelain, 2 is a shade formed integrally on the outer periphery of the body 1 at a constant pitch, A lower metal part 4 cemented to the lower end of the body part 1, and an upper metal part 4 cemented to the upper end of the body part 1. In this embodiment, in order to ensure compatibility with an existing solid insulator for preventing snow damage, the main dimensions are matched, the total length is 1225 mm, the shade pitch is 95 mm, and the number of shades 2 is unified to 11. . As described above, these shades 2 are cut out by a cutting tool while rotating a columnar material.

  FIG. 2 is an enlarged cross-sectional view of the shade shape of the embodiment, and FIG. 3 is an enlarged cross-sectional view of the shade shape of an existing solid insulator for snow damage prevention shown for comparison. Since the feature of the present invention is that the shade shape is devised, it will be described in detail with reference to FIG.

  In FIG. 2, 5 is the outermost first rib formed on the back surface of the shade 2, and 6 is the second rib formed on the inner side. The surface leakage distance of these ribs as a whole is the same as the shade shape of the conventional solid insulator for preventing snow damage shown in FIG. Moreover, the distance from the outer peripheral surface of the trunk | drum 1 to the front-end | tip of the shade 2 is 95 mm, and this is also the same as the shade shape of the conventional solid insulator for snow damage prevention.

  As shown in FIG. 3, in a solid insulator, a short first rib 5 is generally formed at the tip of the shade 2. This is because rainwater that has flowed down the top surface of the shade 2 is dropped at the tip of the shade 2 to prevent the rainwater from entering the backside of the shade 2 and improve electrical insulation. On the other hand, in the present invention, as shown in FIG. 2, the outermost peripheral rib 5 of each shade is provided at a position retracted inward from the tip of the shade 2. Thus, a guide recess 7 is formed at the tip of the shade 2. The outermost rib 5 is drooped more greatly than the other ribs 6.

  With this structure, which is the first feature of the present invention, the wind hitting the tip of the shade 2 is deflected downward on the outer peripheral surface of the outermost rib 5 as shown by the arrow in FIG. It becomes difficult to be caught in the annular recesses 8 and 9, the annular recess 9 between the rib 6 and the body 1, and the like. As a result, the generation of Karman vortices in these annular recesses 8 and 9 is prevented, and wind noise is reduced.

  As shown in FIG. 2, the heights of the lower ends of the plurality of ribs do not exceed the outermost rib. With such a structure, wind sneaking is more reliably prevented and the wind noise reduction effect can be enhanced.

  By increasing the thickness of the shade 2, the rigidity can be increased, and vibration due to wind can hardly occur and wind noise can be reduced. As described above, in the case of a solid insulator having an integral structure unlike the suspended insulator, even if the vibration of the individual shade 2 is small, the entire shade may resonate and generate large wind noise. The meaning of making it thick is great. As shown in Table 1 from previous experiments, No. 1 is an existing solid insulator for preventing snow damage. No. 1 with wall thickness + 5 mm compared to 1. 3 can confirm the reduction of wind noise. No. in Table 1 2 is No.2. Compared to 1, the total thickness of the shade is plus 15 mm, and the increase in thickness due to the curvature is zero. No. No. 2 has an effect of reducing wind noise, but is not preferable because it has a problem in manufacturing and a problem that the distance between the shades becomes small and it becomes weak against snow damage. For these reasons, a thickness of 5 mm or more is preferable for reducing wind noise.

  The effect of reducing wind noise by thickening the shade 2 is effective, but if the shade pitch is narrowed by thickening the shade 2, the effects of antifouling and snow damage, which are the original purposes, are impaired. Therefore, by curving the upper surface of the shade 2 as shown in FIG. 2, the cross-sectional shape of the shade 2 is made streamlined to ensure the wall thickness, and further, the effect of releasing the wind on the shade 2 is enhanced. The existing solid insulators No. 1 for snow damage prevention shown in Table 1 are used. In order to secure a thickness T of 5 mm or more with respect to 1, the curvature radius R of the upper surface of the shade 2 needs to be 275 mm or less from the Pythagorean theorem in FIG. In consideration of production efficiency, the radius of curvature R is preferably about 145 to 275 mm (thickness T is 5 to 10 mm). In FIG. 2, the curvature radius R is 160 mm. In FIG. 7 which is a vertical sectional view passing through the axis, the shade angle line is a straight line AB, point A is a connection point between the top surface of the shade 2 and the outer periphery of the trunk 1, and point B is the top surface of the shade 2 and the shade. It is an intersection with a perpendicular passing through the tip of 2. The wall thickness T means the distance between the shade angle line AB and the central portion of the top surface of the shade 2. W is the length of the shade angle line AB, L is the distance from the outer peripheral surface of the trunk portion 1 to the tip of the shade 2, and θ is the angle formed by the straight line perpendicular to the axis and the shade angle line AB, that is, the shade angle.

  The wind noise prevention solid insulator of the present invention thus configured was subjected to a wind tunnel experiment together with other solid insulators having a shade shape to confirm the occurrence of wind noise. As shown in FIG. 5, the experiment was performed by a method in which a solid insulator was fixed in a wind tunnel, a wind of up to a maximum wind speed of 40 m / s was applied from a 2-m outlet and the generated noise was measured. Since the wind does not always blow horizontally, the experiment was conducted by changing the solid insulator fixing angle from minus 30 ° to plus 30 °.

  When the wind speed is increased, the noise level gradually increases as shown in the graph of FIG. 6, but when a certain wind speed is reached, a phenomenon occurs in which the noise level increases more rapidly than the noise level up to that point. This is an annoying wind sound that is complained by nearby residents, and is called “excellence” in acoustics. On the other hand, the wind noise that gradually increases with the wind speed is a natural phenomenon and not a complaint. Therefore, in addition to the actual wind insulators for wind noise prevention of the present invention, the above experiments were conducted for four types of solid insulators (salt snow-resistant support insulators) with different shade shapes and conventional long trunk insulators. The wind speed is summarized in Table 1. The shade shape is also shown in the table.

  No. Reference numeral 1 is an existing solid insulator for preventing snow damage, and the wind speed when “excellent” occurs is 22 m / s. The occurrence of “excellence” under strong wind conditions is the cause of complaints. No. 2, no. 3 and no. No. 4 is a prototype with an increased thickness of the cap. 2 and No. No. 3 can suppress the occurrence of “excellence”. In No. 4, since the wind speed until the occurrence of “excellence” is 33 m / s and the resistance is increased, the degree of occurrence of “excellence” tends to be alleviated. From the experiments so far, it is necessary to increase the thickness by 5 mm or more in order to expect a reduction in wind noise. However, thickening exceeding 10 mm greatly reduces the productivity, so that thickening of 5 to 10 mm is preferable. No. 2 and No. In the case of No. 3, “excellence” does not occur in the established state, but “excellence” occurs at a wind speed of only 14 to 15 m / s at plus 10 °. Therefore, these are no. Wind noise is more likely to occur than the existing solid insulator 1 for preventing snow damage.

  No. 4 is a product of the present invention, and the wind speed at which “excellence” occurs is 27 m / s or more at any angle from −30 ° to + 30 °. This is equivalent to the wind speed when a typhoon hits, so even if it is drowned out by a strong wind noise and “excellence” occurs, it is hardly noticed. As described above, it was confirmed that the product of the present invention had an excellent effect that no wind noise was generated at a wind speed of less than 27 m / s.

  No. No. 5 is a long trunk insulator that is not used for snow damage prevention, and the total length and voltage class are different, but from “minus 30 ° to plus 20 °”, wind speed of 29.9 m / s or more will not cause “excellence”. . For this reason, it can be seen that there is no particular problem with a general long-legged insulator even if it does not have a shade shape as in the present invention.

DESCRIPTION OF SYMBOLS 1 trunk | drum 2 cap 3 lower metal fitting 4 upper metal fitting 5 1st rib 6 2nd rib 7 recessed part for guide 8 annular recessed part 9 annular recessed part

Claims (2)

A solid insulator in which a plurality of shades with a plurality of ribs suspended from the back surface are formed at a constant pitch on the outer periphery of the trunk, and each shade has an upper surface with a radius of curvature R = {(shade angle line length W / 2) A thickness obtained by inflating upward with a curvature of 5 mm to 10 mm on the shade angle line with a maximum thickness obtained by ² + thickness T ² } / (2 × thickness T) mm, and each shade The outermost rib of the outer wall of the outermost rib hangs down more than the other ribs, and is provided at a position retracted inward from the tip of the cap, thereby providing a guide recess that deflects the wind hitting the cap at the outer peripheral surface of the outermost rib Wind noise prevention Nakashiko that is characterized by forming. 2. The wind noise preventing solid insulator according to claim 1, wherein each shade has the same shape .