| Title of Invention | "POWER TRANSMISSION LINE SUPPORT" |
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| Abstract | A supporting structure for an electric power line comprising side faces (2) with stiffening ribs (3) made of bent metal sheet sections attached to each other and forming its triangular cross-section, surfaces of two side faces (3) and stiffening ribs of each post are made of a solid V-bent shaped sheet strip with end bends, with its three sheet fold ribs forming bearing structure angular chord rigid profiles (1), with two equidimensional planes between them forming adjacent side faces, with two sheet flat end bends forming stiffening ribs inclined at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements (4) forming a third side face surface with the stiffening ribs being symmetric about different web face sides in the same plane, is characterized in that it is provided with an extra stiffening rib (6) perpendicular to the web side face surfaces and to stiffening ribs and made solid on the outside of the structure as a triangle along the entire height of the structure or as a rectangle or trapezium or in the form of elements distantly located on the adjacent side face fold rib. |
| Full Text | 1 A SUPPORTING STRUCTURE FOR AN ELECTRIC POWER LINE Sphere of the Invention The invention refers to a supporting structure for an electric power line, specifically truss-type support structures for high voltage electric power transmission line. Prior Knowledge In the most widely used and secure self-supporting (guyless) structures the stress in the post chords is determined primarily by bending moments caused by loads which under normal conditions areperpendicular to the high voltage line axis and in breakdown situations parallel to such axis. As the bending moments are smaller in top sections and greater in the bottom ones the sections are made with sloping chords to level down the stresses as much as possible in the top and bottom panel chords of each section. The stresses being equal makes it possible to fully utilize the chords' material strength along the entire section height, thus minimizing the chord steel requirements. However, a steep chord slope results in widened vertical posts in the support bottom part, a heavier web and a need for three or four foundations to install the supports. In order to reduce the space for the power transmission line support structures, the number of foundations and the web weight at present narrow-base supports fixed to only one foundation are used. When the vertical posts of such supports are made similar in design to broad-base one the chord stress increases due to the decreased width of posts and the stresses in the top and bottom panels of each section differ greatly because of more flat chord slope. 1A Thus, the strength of chords chosen to match the maximum stresses (in the bottom panels) remains underutilized in other section panels. This is why the steel requirements of narrow-base support chords is substantially increased. 2 The above-mentioned negative features of the narrow-base supports similar in design to those of the broad-base type are partially avoided by using narrow-base roll-formed sheet polyhedral posts of solid cross-section in the form of a regular polygon. The posts described in US No. 5117607, EO4H 12/08 published on 02.07.1992 or in EP No. 0407998, EO4H 12/10 published on 16.01.1991 may serve as an example of such design. In both examples the polyhedral post cross-section normally grows smaller from maximum at the bottom to minimum in the top part proportionally to the bending moment decrease so as to save the material. Similar structures have also found application as type-design supports for 110 and 220 kV high voltage power transmission lines (See "High Voltage Power Units Guidebook", M., Energoatomizdat, 1989, pp. 425-426, and the "Manual for Designing High Voltage Line Supports and Substantion OPY Units over 1 kV", M, Central Institute of Type Design, 1989, pp. 58-59), A disadvantage of the support with the post of a solid polyhedral cross-section is rather substantial material consumption, as in the process of bending the stress in fibers located in section neutral axis area proves to be significantly lower than the permissible one, i.e. the material strength_in these fibers is not utilized in full. A well-known long-sized bearing structure of the power transmission line post includes side faces with stiffening ribs made of bent metal sheet sections attached to each other and forming its triangular cross-section, surfaces of two side faces and stiffening ribs of each post section are made of a solid V-bent shaped sheet strip with end bends, with its three sheet fold ribs forming bearing structure angular chord rigid profiles, with two equidimensional planes between them forming adjacent side faces in the shape of trapeziums, with two sheet flat end bends forming stiffening ribs in 3 the form of parallelograms at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements forming a third side face surface in the form of an equilateral trapezium of the bearing structure, with the stiffening ribs being symmetric about different web face sides in the same plane (RU patent No. 2083785, EO4H 12/00, published on 10.07.1997). The support structure designed from a prototype has high mechanical strength due to a rational cross-section configuration which varies along the entire length of the frameless space truss. The prototype design mechanical strength, however, varies in directions along and across the power transmission line axis because of the support post profile asymmetry about the axis which is perpendicular to the power transmission line direction. The proposed structure has a higher mechanical strength against loads across the power transmission line axis (operating conditions loads) and a lower mechanical strength against loads along the power transmission line axis (emergency conditions loads). When using in the power transmission line wires of a big cross-section the emergency conditions loads may exceed a bearing ability of the post which will cause the operating tension in the wire to be decreased because of the decreased spans between the neighbouring supports along the line route which in turn will result in erecting extra supports during the construction of the power transmission line and respectively in greater cost of the power transmission line construction. Therefore, it is expedient to find a way of increasing the mechanical strength of the support post against bending moments acting on the truss along the power transmission line axis. Invention Disclosure This invention is aimed at solving an engineering task of increasing the mechanical strength of the space truss against bending moments without the 4 chord metal sheet thickness being increased and without the truss base being extended due to the change of the post profile. The engineering outcome in this case will be a higher mechanical strength of the support for emergency conditions loads along the power transmission line axis. This enables one in using in the power transmission line wires of a big cross-section not to increase the number of supports, thus reducing the cost of the power transmission line construction. The above engineering result is achieved by the fact that the support structure for the electric power transmission line comprising side faces with stiffening ribs made of bent metal sheets sectionally abutted with each other and forming its triangular cross-section, the surfaces of two side faces and stiffening ribs of each post section of solid V bent shaped sheet strip with end bends forming with three sheet fold ribs bearing structure angular chord rigid profiles, with two equidimensional planes between them forming adjacent side faces, with two sheet flat end bends forming stiffening ribs at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements forming a third side face surface, with the stiffening ribs being symmetric about different web face sides in the same plane, is provided with an extra stiffening rib perpendicular to the web side face and to stiffening ribs and made solid or in the form of elements distantly located on the adjacent side face bend rib on the outside of the structure. When making a solid extra rib in the direction of the power transmission line the base of triangle or trapezium is in the bottom part of the support structure. The distantly located elements may be in the form of rectangles or trapeziums of the same or different size. 5 These characteristic features are new as compared with well-known analogues and in the aggregate they are necessary to achieve a new engineering result consisting in the creation of a light-weight quick eractable support structure for the high voltage power transmission line of an increased stability and mechanical strength under normal and emergency conditions. Brief Description of Drawings The invention is illustrated by drawings where: Fig. 1 - Overview of the long-sized support structure for the power transmission line, general view from the extra stiffening rib side; Fig. 2 - The support structure, back view; Fig. 3 - The support structure cross-section, top view; Fig. 4 - The first example of the support structure with a solid extra stiffening rib in the form of a rectangle; Fig. 5 - The second example of the support structure with a solid extra stiffening rib in the form of a trapezium; Fig. 6 - The third example of the support structure with a solid extra stiffening rib in the form of a triangle; Fig. 7 - The first example of the support structure design with an extra stiffening rib as separate plates in the form of rectangles of the same size; Fig. 8 - The second example of the support structure with an extra stiffening rib as separate planes in the form of rectangles of different size; Fig. 9 - The third example of the support structure with an extra stiffening rib as separate plates in the form of trapeziums of the same size. Best Versions of Realization of the Invention According to the invention the support structure for the power transmission line includes side faces with stiffening ribs made of bent metal sheet sections attached to each other and making up its triangular cross- 6 section. The surfaces of two side faces and stiffening ribs of each post section are made of a solid V-bent shaped sheet strip with end bends, with three ribs of the sheet folds forming rigid profiles of the bearing structure angular chords; with two equidimensional planes between them forming adjacent side faces, with two flat end sheet bends forming stiffening ribs sloping at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements forming a third side face surface. The stiffening ribs are symmetric about different web face sides in the same plane. To increase the mechanical strength of the support along the power transmission line axis an extra stiffening rib is made a part of the support cross-section structure on the power transmission line axis. The extra stiffening ribs is perpendicular to the web side face surfaces and stiffening ribs and located on the outside of the structure as a solid triangle along the entire height of the structure or a rectangle or a trapezium or in the form of elements distantly located on the adjacent side face bend rib. When installing a solid extra rib in the direction of the power transmission line the base of triangle or trapezium is in the bottom part of the support structure. The distantly located elements may be in the form of rectangles or trapeziums of the same or different size. Specific examples of the support structure design for the power transmission line are given below. The long-sized bearing structure of the power transmission line support post includes angular chords 1, adjacent side faces 2, stiffening ribs 3, web element 4, post flange joint 5. All post load-bearing elements are made of a single solid metal rolled sheet cut into V-shaped planes forming adjacent side faces 2 and stiffening ribs 3 of a hollow frameless space truss as a truncated pyramid (Fig. 1). 7 Adjacent side faces 2 of the pyramid are congruent (equidimensional) and symmetrically abut with each other along the common metal sheet bend rib forming a pyramid side rib and at the same time angular chord 1 of the bearing structure. The ends of the V-shaped solid sheet are also symmetrically bent to the opposite external sides and form stiffening ribs 3 with the planes in the form of parallelograms; the metal bend angles in this case form pyramid side ribs and bearing structure angular chords 1. The adjacent side face 2 planes of the truncated pyramid are made in the form of trapezium and are at an obtuse angle to the planes of stiffening ribs 3 attached to each other by web elements 4, e.g. diagonals of angle profile (Fig. 2). Web elements are located in the same plane as stiffening ribs 3 and together with opposite chords 1 form third side face 2 of the truncated pyramid and the bearing structure post rigid joints. The plane of third side face 2 is made in the form of a equilateral trapezium with all sides, as in the case of stiffening rib 3 planes, being congruent, i.e. the angles of the sides of the same direction are equal. Angle a between side faces 2 is chosen according to the ratio of bending moments acting on the support structure in the direction of perpendicular axes X and Y (Fig. 3) with allowance made for coefficients decided by the relationship between the sectional areas of the support structure stiffening ribs and side faces. Congruency of the bearing structure shaped planes favours uniform load distribution in respect of the post elements of the truncated pyramid side face 2 plane; web elements 4 of the third side face triangular cross-sections of the pyramid of lesser area - at the top of the bearing structure and of greater area - at its base. 8 The bearing structure of a cross-section in the form of an equilateral triangle may have one or two angular chords 1 made perpendicular to the top and bottom planes of the truncated pyramid bases which increases the stability of the support post lengthwise the power transmission line axis and the stability in the lateral direction is obtained due to stiffening rib 3-planes. Sloping side faces 2 made of a solid metal sheet and web elements 4 with sloping stiffening ribs 3 increase the bearing structure mechanical strength against bending loads and axial rotation under normal and emergency conditions. Web elements 4 facilitate post erection in the design position and ensure ease of attendance of the power transmission line support electrical area. For convenience of transportation to remote areas of the route the long-sized support structure may be made with sections of solid bent sheet strips to shape on the edges; at the erection side the sheet strips are attached to each other from the inside by bolted flange joints or by welding. To increase the support mechanical strength along the power transmission line axis extra stiffening rib 6 is made a part of the support cross-section structure, such extra rib is placed during the erection work on the power transmission line axis. Extra stiffening rib 6 may be made solid along the entire support height (figs. 4, 5,6) or as separate plates (Figs. 7, 8, 9) located in the support post cross-section at a certain distance. Depending on loads acting on the structure stiffening rib 6 may be made in the form of a triangle (Fig. 6), a rectangle (Fig. 4) or a trapezium (Fig. 5). In the case of a rib as a triangle its base is in the bottom part of the support, in the case of a rib as a trapezium the latter's base is in the bottom part of the support. Stiffening rib 6 may be made as separate planes 7 distantly located in the form of rectangles of the same (Fig. 7) or different (Fig. 8) size. Stiffening 9 rib 6 may be made as separate plates 7 in the form of trapeziums of different size (Fig. 9). An extra stiffening rib in the direction along the power transmission line increases the support mechanical strength without widening the base by eliminating asymmetry of the post profile about the axis perpendicular to the power transmission line direction. Industrial Applicability This invention is industrially practicable because its realization does not require any special technology except the one already used nowadays for producing truss structures. 10 CLAIMS: 1. A supporting structure for an electric power line comprising side faces with stiffening ribs made of bent metal sheet sections attached to each other and forming its triangular cross-section, surfaces of two side faces and stiffening ribs of each post are made of a solid V-bent shaped sheet strip with end bends, with its three sheet fold ribs forming bearing structure angular chord rigid profiles, with two equidimentional planes between them forming adjacent side faces, with two sheet flat end bends forming stiffening ribs inclined at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements forming a third side face surface with the stiffening ribs being symmetric about different web face sides in the same plane, characterised in that it is provided with an extra stiffening rib perpendicular to the web side face surfaces and to stiffening ribs and made solid on the outside of the structure as a triangle along the entire height of the structure or as a rectangle or trapezium or in the form of elements distantly located on the adjacent side face fold rib. 2. A supporting structure as claimed in claim 1, wherein the triangle or trapezium base is in the support structure bottom part. 3. A supporting structure as claimed in claim 1, wherein distantly located elements are made in the form of rectangles of the same or different size. 11 4. A supporting structure as claimed in claim 1, wherein distantly located elements are made in the form of trapeziums of the same or different size. 5. A supporting structure as claimed in claim 1, wherein an extra stiffening rib is located in the direction of the power transmission line. A supporting structure for an electric power line comprising side faces (2) with stiffening ribs (3) made of bent metal sheet sections attached to each other and forming its triangular cross-section, surfaces of two side faces (3) and stiffening ribs of each post are made of a solid V-bent shaped sheet strip with end bends, with its three sheet fold ribs forming bearing structure angular chord rigid profiles (1), with two equidimensional planes between them forming adjacent side faces, with two sheet flat end bends forming stiffening ribs inclined at an obtuse angle to the planes of the adjacent side faces and attached to each other by web elements (4) forming a third side face surface with the stiffening ribs being symmetric about different web face sides in the same plane, is characterized in that it is provided with an extra stiffening rib (6) perpendicular to the web side face surfaces and to stiffening ribs and made solid on the outside of the structure as a triangle along the entire height of the structure or as a rectangle or trapezium or in the form of elements distantly located on the adjacent side face fold rib. |
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| Patent Number | 203613 | |||||||||
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| Indian Patent Application Number | 00075/KOLNP/2004 | |||||||||
| PG Journal Number | 11/2007 | |||||||||
| Publication Date | 16-Mar-2007 | |||||||||
| Grant Date | 16-Mar-2007 | |||||||||
| Date of Filing | 21-Jan-2004 | |||||||||
| Name of Patentee | GUNGER YURY ROBERTOVICH | |||||||||
| Applicant Address | 630106 RUSSIA,NOVOSIBIRSK,PETYKHOVA D.82/3,KV.3 | |||||||||
Inventors:
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| PCT International Classification Number | B04H12/00 | |||||||||
| PCT International Application Number | PCT/RU01/00461 | |||||||||
| PCT International Filing date | 2001-11-01 | |||||||||
PCT Conventions:
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