The energy industry has a very big problem: Professionals born between the mid-1940s and mid-1960s are approaching retirement age. And a very big question arises: who will replace them?
Overcoming barriers to renewable energy
Despite certain achievements in last years, energy from renewable sources is a very modest part of modern services to provide energy around the world. Why is it so?
Real-time power transmission monitoring
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Material capable of making solar power 'surprisingly cheap'
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Comparison of SF6 and vacuum circuit breakers for medium voltage
Experience in the development of medium voltage circuit breakers, both SF6 and vacuum, has provided sufficient evidence that neither of these two technologies is, in general, significantly superior to the other. Decision-making in favor of this or that technology is stimulated by economic factors, user preferences, national "traditions", competence and special requirements.
Medium voltage switchgear and LSC
Metal-encased medium voltage switchgear and loss of service (LSC) categories - categories, classification, examples.
What factors will affect the future of transformer manufacturers?
Whether you generate or sell electricity, or supply power transformers outside the country, you are forced to fight competition on global market. There are three main categories of factors that will influence the future of all transformer manufacturers.
The future of medium voltage switching equipment
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In search of a replacement for SF6 gas
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Advantages and types of switchgear
It is desirable to place the electrical substation in the center of the load. However, often the main obstacle to such substation placement is the space required for it. This problem can be solved by applying GIS technology.
Vacuum as arc quenching medium
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Self-healing networks come to Holland
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AC generator breakers
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A look through switching equipment
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Thermal imaging inspection of electrical substations
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hybrid switch
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MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATION
Federal State Budgetary Educational Institution of Higher Professional Education
Kazan State University of Architecture and Civil Engineering
Department of Geodesy
SELECTED SYMBOLS
Guidelines
To perform settlement and graphic work by students studying in the direction of "Construction".
Kazan-2012
Compiled by: V.S. Borovskikh, M.G. Ishmukhametova
Selected symbols. Guidelines for the performance of settlement and graphic work by students of the 1st year of full-time education in the direction of "Construction". Methodological instructions correspond to the State General Educational Standard.
Kazan State University of Architecture and Civil Engineering.
Comp.: V.S.Borovskikh, M.G.Ishmukhametova
Kazan, 2012 - 17 p.
ill. 90, table 1
Reviewer: SNS, Associate Professor, PhD, Department of Astronomy, Kazan State University M.I. Shpekin
C Kazan State University of Architecture and Civil Engineering
In "Selected Conventional Signs for Topographic Plans at Scales 1:500 and 1:1000" ", the conventional signs of the most common contours and objects of the area are given. They need to be learned and known by students studying at the university. "Selected Conventional Signs" are used when performing calculation graphic work and during summer geodetic practice for drawing plans for theodolite, tacheometric surveys, leveling by squares.
To draw topographic plans and maps of smaller scales, conventional symbols are used, which, as a rule, are similar in appearance to conventional symbols for scales of 1:500 - 1:1000.
In the "Selected Conventional Signs" in the first column are serial numbers. Symbols are selected from the official publication "Symbols for topographic plans at scales 1:5000, 1:2000, 1:1000, 1:500" - M.: Nedra, 2002, approved by the GUGK of Russia. The second column contains the names of conventional signs and explanations for them, and the third - the image of various signs and their sizes. When drawing plans, the dimensions of the symbols must be observed, but not shown.
When drawing off-scale symbols, images of objects should be placed perpendicular to the southern frame of the plan.
The position of the object on the ground must correspond to the following points of the off-scale sign on the plan:
a) for signs of the correct form (circle, square, etc.) - the center of the sign;
b) for signs with a right angle at the base - the top of the corner;
c) for signs in the form of a perspective image of an object - the middle of the base of the sign.
To draw conventional signs on plans and maps, ink and watercolors of different colors are used. The colors are shown in the explanations of the symbols. If there are no such explanations, the symbols are depicted in black ink.
SELECTED SYMBOLS
for topographic plans
scales 1:1000, 1:500
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Name and characteristics of a topographic object |
Symbol of a topographic object |
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Points of the state geodetic network |
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Points of the state geodetic network on the mounds |
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Points of the state geodetic network on buildings |
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Points of geodetic thickening networks and their numbers |
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Leveling benchmarks and their numbers |
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Leveling benchmarks and wall marks |
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Leveling benchmarks ground construction long-term |
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Temporary leveling benchmarks |
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Intersections of coordinate lines ( in green) |
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buildings: Residential fire-resistant: (brick, stone, concrete) 1) single deck; 2) above one floor |
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Non-residential fire-resistant buildings: (brick, stone, concrete) 1) single deck; 2) above one floor |
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Non-fire-resistant residential buildings: (wooden, adobe, etc.) 1) single deck; 2) above one floor |
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Non-residential non-fire-resistant buildings (wooden, adobe, etc.) 1) single deck; 2) above one floor |
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Buildings under construction |
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Buildings destroyed and dilapidated |
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Marking the height of the floor of the first floor (inside the contour); Ground mark on the corner of the house |
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1) stone with domes of different heights; 2) wooden with one dome |
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1) stone; 2) wooden |
1)2) |
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Small buildings: 1) individual garages; 2) toilets |
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slopes: Unfortified (number 2,5 - slope height in meters) |
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Unreinforced slopes (figure 102,5 - slope height in meters) |
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Reinforced slopes (number 102,5 - slope height in meters; inscription - a way to strengthen) |
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Open pit mining of solid minerals (quarries, etc. (figure - depth in meters) |
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gas stations |
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Electrical substations, transformer boxes, and their numbers |
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Wells and wells combined with water towers |
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Electric lamps on poles |
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Manholes (manholes) underground utilities: 1) without appointment; 2) on water supply networks; 3) on sewer networks; 4) on heating systems; 5) on gas pipelines |
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Power lines (TL) in an undeveloped area (figures - truss heights in meters, voltage in kV, number of wires or cables): 1) high voltage power lines on reinforced concrete trusses; 2) High voltage power lines on metal trusses; 3) cable overhead power line high voltage on reinforced concrete and wooden poles; 4) Low voltage power lines on metal and wooden poles |
1)
2)
3)
4)
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Power lines (TL) in built-up area: 1) High voltage power lines on wooden farms; 2) high voltage power lines on poles; 3) high voltage cable overhead power lines on poles; 4) Low voltage power lines on wooden poles |
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Pipelines: Ground ( G- gas pipeline, AT- water pipes, To- sewerage, H- oil pipelines; pipe material - bet., st. and etc.; figures - pipe diameter in millimeters): 1) ground on the ground; 2) on supports (numbers are the height of the supports in meters) |
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Underground pipelines: 1) pipelines with inspection wells (numbers - numbers and elevations of wells; ch. 1.2- pipe laying depth); 2) pipelines laid side by side in one trench (numbers - the number of gaskets); |
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Waste gratings |
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Surface pipelines on supports (green wash) |
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Pipelines on the bottom surface (green hillshade) |
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Communication lines and technical means air wired controls (telephone, radio, television, etc.) |
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Masts, towers, radio and television repeaters (numbers are their heights in meters) |
1:1000 1:500 |
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Landfill (dashed lines brown) |
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Construction sites |
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Roads: 1) highways (covering material - concrete); cuvettes in green. 2) car roads with improved surface (asphalt); cuvettes in green. |
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Roadways and sidewalks: laundering pink ; 1) carriageways of streets in the presence of side stone; 2) carriageways of streets without side stone; 3) sidewalks with a hard surface; 4) unpaved sidewalks |
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Unpaved roads: 1) improved dirt roads; cuvettes in green. 2) dirt roads (field, forest, country roads); |
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Roads in recesses (numbers are the depths of recesses in meters); cuvettes in green. |
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Railways |
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Narrow gauge railways (appointment and gauge in millimeters) |
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Railways on embankments (figures - height of embankments in meters) |
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Station tracks |
1:1000 |
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Pedestrian bridges over railways (letters - bridge material) |
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Horizontals (in brown): 1) thickened (through a given interval of section height); 2) basic; 3) semi-horizontal (half the height of the section); 4) quarter-horizontal (in 1/4 section height) |
3)
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Slope direction indicators (bergstrokes) |
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Height marks |
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Ground cliffs (in brown): (numbers - depth in meters) |
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Pits (numbers - depth in meters) |
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Mounds (numbers - height in meters) |
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watercourses, coastlines and marks of water edges (height and date of measurement), Border of land and water in green, hillshade blue color. |
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Streams (width not expressed in plan scale) in blue. |
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Characteristics of watercourses: 2) width in meters (numerator), depth in meters and bottom soil (denominator) |
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Bridges: 1) in general superstructure(metal - metal, stone - stone, reinforced concrete, figures - load capacity in tons); 2) small wooden; |
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Vegetation: Contours of vegetation, agricultural land, soil, etc. |
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Characteristics of forest stands by composition: 1) deciduous; 2) coniferous; 3) mixed; according to qualitative data: 4) average height of trees in meters (numerator), average thickness of trunks in meters (denominator), average distance between trees in meters (number on the right), tree species |
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Natural tall forests |
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Young forest plantations (figure - average height in meters) |
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Forest areas cut down |
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Shrubs separate groups |
Depending on the method of suspension of wires, the supports of overhead lines (VL) are divided into two main groups:
a) intermediate supports, on which the wires are fixed in supporting clamps,
b) anchor type supports used to tension the wires. On these supports, the wires are fixed in tension clamps.
The distance between the supports (power lines) is called the span, and the distance between the anchor type supports is anchored section(Fig. 1).
According to the intersection of some engineering structures, For example railways common use, must be performed on anchor-type supports. At the corners of the line, corner supports are installed, on which the wires can be suspended in support or tension clamps. Thus, the two main groups of supports - intermediate and anchor - are divided into types that have a special purpose.
Rice. 1. Scheme of the anchored section of the overhead line
Intermediate straight supports are installed on straight sections of the line. On intermediate supports with suspension insulators, the wires are fixed in supporting garlands hanging vertically; on intermediate supports with pin insulators, the wires are fixed by wire knitting. In both cases, intermediate supports perceive horizontal loads from wind pressure on the wires and on the support, and vertical - from the weight of wires, insulators and the own weight of the support.
With unbroken wires and cables, intermediate supports, as a rule, do not perceive the horizontal load from the tension of wires and cables in the direction of the line and therefore can be made more light construction than supports of other types, for example, end supports that perceive the tension of wires and cables. However, to ensure reliable operation of the line, intermediate supports must withstand some loads in the direction of the line.
Intermediate corner supports installed at the corners of the line with a suspension of wires in supporting garlands. In addition to the loads acting on the intermediate straight supports, the intermediate and anchor angle supports also perceive loads from the transverse components of the tension of the wires and cables.
At angles of rotation of the power line of more than 20 °, the weight of the intermediate corner supports increases significantly. Therefore, intermediate corner supports are used for angles up to 10 - 20°. At large angles of rotation, anchor angle supports.
Rice. 2. Intermediate supports VL
Anchor supports. On lines with suspension insulators, the wires are fixed in the clamps of the tension garlands. These garlands are, as it were, a continuation of the wire and transfer its tension to the support. On lines with pin insulators, the wires are fixed on anchor supports with reinforced viscous or special clamps that ensure the transfer of the full tension of the wire to the support through the pin insulators.
When installing anchor supports on straight sections of the route and suspending wires on both sides of the support with the same tensions, the horizontal longitudinal loads from the wires are balanced and the anchor support works in the same way as the intermediate one, i.e. it perceives only horizontal transverse and vertical loads.
Rice. 3. Anchor-type overhead line supports
If necessary, the wires on one and the other side of the anchor support can be pulled with different tension, then the anchor support will perceive the difference in tension of the wires. In this case, in addition to the horizontal transverse and vertical loads, the horizontal longitudinal load will also act on the support. When installing anchor supports at the corners (at the turning points of the line), the anchor corner supports also perceive the load from the transverse components of the tension of the wires and cables.
End supports are installed at the ends of the line. From these supports depart wires suspended on the portals of substations. When hanging wires on the line until the end of the construction of the substation, the end supports perceive full one-sided tension.
In addition to the listed types of supports, special supports are also used on the lines: transpositional, which serve to change the order of the wires on the supports, branch - to carry out branches from the main line, support for large river crossings and bodies of water and etc.
The main type of supports on overhead lines are intermediate ones, the number of which is usually 85 -90% total number supports.
According to the design of the support can be divided into free-standing and braced supports. Guys are usually made of steel cables. On overhead lines, wooden, steel and reinforced concrete supports are used. Designs of supports made of aluminum alloys have also been developed.
Structures of overhead lines
- Wooden support LOP 6 kV (Fig. 4) - single-column, intermediate. It is made of pine, sometimes larch. The stepson is made of impregnated pine. For 35-110 kV lines, wooden U-shaped two-column supports are used. Additional elements support structures: hanging garland with hanging clip, traverse, braces.
- Reinforced concrete supports are made as single-column free-standing, without braces or with braces to the ground. The support consists of a post (trunk) made of centrifuged reinforced concrete, a traverse, a lightning protection cable with a ground electrode on each support (for lightning protection of the line). With the help of a grounding pin, the cable is connected to a grounding conductor (a conductor in the form of a pipe hammered into the ground next to the support). The cable serves to protect the lines from direct lightning strikes. Other elements: rack (trunk), traction, traverse, cable rack.
- Metal (steel) supports (Fig. 5) are used at a voltage of 220 kV or more.
Types of overhead lines
In the production of metal structures for power lines There are the following types of overhead lines:
intermediate power transmission towers,
power line anchor supports ,
power line corner poles and special hardware for power lines. Varieties of types of structures of overhead power lines, which are the most numerous on all power lines, are intermediate supports that are designed to support wires on straight sections of the route. All high-voltage wires are attached to power transmission traverses through supporting insulator garlands and other structural elements of overhead power lines. In normal mode, this type of overhead line supports perceive loads from the weight of adjacent half-spans of wires and cables, the weight of insulators, linear fittings and individual support elements, as well as wind loads due to wind pressure on wires, cables and the metal structure of the power transmission line itself. In emergency mode, the structures of intermediate supports of power transmission lines must withstand the stresses that occur when one wire or cable breaks.
The distance between two adjacent intermediate supports VL called an intermediate span. Corner supports VL can be intermediate and anchor. Intermediate corner elements of power transmission lines are usually used at small angles of rotation of the route (up to 20 °). Anchor or intermediate corner elements of power transmission lines are installed in sections of the line route where its direction changes. Intermediate corner supports of overhead lines in normal mode, in addition to loads acting on ordinary intermediate elements of power lines, perceive the total effort from the tension of wires and cables in adjacent spans, applied at the points of their suspension along the bisector of the angle of rotation of the power line. The number of anchor corner supports of overhead lines is usually a small percentage of the total number on the line (10 ... 15%). Their use is determined by the conditions of installation of lines, the requirements for the intersection of lines with various objects, natural obstacles, i.e. they are used, for example, in mountainous areas, and also when intermediate corner elements do not provide the required reliability.
Are used anchor angle supports and as terminal wires from which the wires of the line go to the switchgear of the substation or station. On lines passing in populated areas, the number of anchor corner elements of power lines also increases. The wires of the overhead line are fastened through the tension garlands of insulators. In normal mode, these power line supports , in addition to the loads indicated for the intermediate elements of the stucco, there is a difference in tension along the wires and cables in adjacent spans and the resultant of the gravitational forces along the wires and cables. Usually, all anchor-type supports are installed so that the resultant of the gravitational forces is directed along the axis of the support traverse. In emergency mode, the anchor posts of power lines must withstand the breakage of two wires or cables. The distance between two adjacent anchor supports of power lines called an anchor span. Branching elements of power transmission lines are designed to carry out branches from main overhead lines, if necessary, to supply electricity to consumers located at some distance from the route. Cross elements are used to cross wires of overhead lines in two directions on them. End racks of overhead lines are installed at the beginning and end of the overhead line. They perceive the forces directed along the line, created by the normal one-sided tension of the wires. For overhead lines, power transmission line anchor supports are also used, which have increased strength compared to the types of racks listed above and a more complex design. For overhead lines with voltages up to 1 kV, reinforced concrete racks are mainly used.
What are power transmission towers? Classification of varieties
According to the method of fixing in the ground, they are classified:
VL supports installed directly into the ground - Power transmission line supports installed on foundations Varieties of power transmission line supports by design:
Free-standing power line poles - Guyed poles
By the number of circuits, power transmission towers are classified:
Single circuit - Double circuit - Multi circuit
Unified transmission line poles
Based on many years of practice in the construction, design and operation of overhead lines, the most appropriate and economical types and designs of supports for the corresponding climatic and geographical regions are determined and their unification is carried out.
Designation of power transmission towers
For metal and reinforced concrete supports VL 10 - 330 kV adopted the following designation system.
P, PS - intermediate supports
PVS - intermediate supports with internal connections
PU, PUS - intermediate corner
PP - intermediate transitional
U, US - anchor-angular
K, KS - terminal
B - reinforced concrete
M - Polyhedral
How are overhead lines marked?
The numbers after the letters in the marking indicate the voltage class. The presence of the letter "t" indicates a cable rack with two cables. The number through a hyphen in the marking of the overhead line supports indicates the number of circuits: odd, for example, a unit in the numbering of a power transmission line support is a single-circuit line, an even number in the numbering is two and multi-circuit. The number through "+" in the numbering means the height of the attachment to the base support (applicable to metal).
For example, symbols for overhead lines: U110-2+14 - Metal anchor-angled double-chain support with a stand 14 meters PM220-1 - Intermediate metal polyhedral single-chain support
Overhead power lines. Support structures.
Supports and foundations for overhead power lines with a voltage of 35-110 kV have significant specific gravity both in terms of material consumption and cost. Suffice it to say that the cost of the mounted support structures on these overhead lines is, as a rule, 60-70% of the total cost of the construction of overhead power lines. For lines located on industrial enterprises and the territories immediately adjacent to them, this percentage may be even higher.
Overhead line supports are designed to support line wires at a certain distance from the ground, ensuring the safety of people and reliable operation of the line.
Overhead power line towers are divided into anchor and intermediate. The supports of these two groups differ in the way the wires are suspended.
Anchor supports completely perceive the tension of wires and cables in spans adjacent to the support, i.e. serve to stretch the wires. On these supports, the wires are suspended with the help of hanging garlands. Anchor type supports can be of normal and lightweight construction. Anchor supports are much more complicated and more expensive than intermediate ones, and therefore their number on each line should be minimal.
Intermediate supports do not perceive the tension of the wires or perceive it partially. On the intermediate supports, the wires are suspended with the help of insulators supporting garlands, fig. one.
Rice. one. Scheme of the anchor span of the overhead line and the span of the intersection with the railway
On the basis of anchor supports can be performed end and transposition supports. Intermediate and anchor supports can be straight and angled.
End anchor supports installed at the exit of the line from the power plant or at the approaches to the substation are in the worst conditions. These supports experience one-sided tension of all wires from the side of the line, since tension from the side of the substation portal is insignificant.
Intermediate lines supports are installed on straight sections of overhead power lines to support wires. An intermediate support is cheaper and easier to manufacture than an anchor one, since in normal mode it does not experience forces along the line. Intermediate supports make up at least 80-90% of the total number of overhead line supports.
Angle supports are set at the turning points of the line. At angles of rotation of the line up to 20 °, angled anchor-type supports are used. At angles of rotation of the power line more than 20 ° - intermediate corner supports.
On overhead power lines are used special supports the following types: transpositional- to change the order of the wires on the supports; branch- to carry out branches from the main line; transitional- for crossing rivers, gorges, etc.
Transposition is used on lines with a voltage of 110 kV and above with a length of more than 100 km in order to make the capacitance and inductance of all three phases of the overhead power transmission line circuit the same. At the same time, the relative position of the wires in relation to each other is consistently changed on the supports. However, such a triple movement of wires is called a transposition cycle. The line is divided into three sections (steps), in which each of the three wires occupies all three possible positions, fig. 2.
Rice. 2. Single Circuit Wire Transposition Cycle
Depending on the number of chains suspended on the supports, the supports can be single and double chain. The wires are located on single-circuit lines horizontally or in a triangle, on double-circuit supports - reverse tree or hexagon. The most common arrangements of wires on supports are schematically shown in fig. 3.
Rice. 3. The most common arrangement of wires and cables on supports:
a - location along the vertices of the triangle; b - horizontal arrangement; in - the location of the reverse Christmas tree
The possible location of lightning protection cables is also indicated there. The location of the wires along the vertices of the triangle (Fig. 3, a) is widespread on lines up to 20-35 kV and on lines with metal and reinforced concrete supports with a voltage of 35-330 kV.
The horizontal arrangement of wires is used on 35 kV and 110 kV lines on wooden poles and on higher voltage lines on other poles. For double-circuit supports, the arrangement of wires according to the “reverse tree” type is more convenient from the point of view of installation, but it increases the weight of the supports and requires the suspension of two protective cables.
wooden supports were widely used on overhead power lines up to 110 kV inclusive. Pine poles are the most common, and larch poles are somewhat less common. The advantages of these supports are low cost (in the presence of local wood) and ease of manufacture. The main disadvantage is the decay of wood, which is especially intense at the point of contact of the support with the soil.
Metal supports are made of steel of special grades for lines of 35 kV and above, require a large amount of metal. Individual elements connected by welding or bolts. To prevent oxidation and corrosion, the surface of metal supports is galvanized or periodically painted with special paints. However, they have high mechanical strength and long service life. Install metal supports on reinforced concrete foundations. These supports, according to the constructive solution of the support body, can be attributed to two main schemes - tower or single rack, rice. 4, and portal, rice. 5.a, according to the method of fixing on the foundations - to free-standing supports, fig. 4 and 6, and braced supports, rice. 5.a, b, c.
On metal supports with a height of 50 m or more, ladders with railings reaching the tops of the support should be installed. At the same time, platforms with fences should be made on each section of the supports.
Rice. 4. Intermediate metal support of single circuit line:
1 - wires; 2 - insulators; 3 - lightning protection cable; 4 - cable rack; 5 - support traverses; 6 - support post; 7 - support foundation
Rice. 5. Metal supports:
a) - intermediate single-circuit on braces 500 kV; b) - intermediate V-shaped 1150 kV; in) - intermediate support DC overhead line 1500 kV; d) - elements of spatial lattice structures
Rice. 6. Metal free-standing double chain poles:
a) - intermediate 220 kV; b) - anchor angle 110 kV
Reinforced concrete supports are performed for lines of all voltages up to 500 kV. To ensure the required density of concrete, vibrocompaction and centrifugation are used. Vibrocompaction is performed by various vibrators. Centrifugation provides very good compaction of concrete and requires special machines - centrifuges. On overhead power lines of 110 kV and above, the pillars of the supports and the traverses of the portal supports are centrifuged pipes, conical or cylindrical. Reinforced concrete supports are more durable than wooden ones, there is no corrosion of parts, they are easy to operate and therefore they are widely used. They have a lower cost, but have a greater mass and relative fragility of the concrete surface, Fig. 7.
Rice. 7. Intermediate reinforced concrete free-standing single-circuit
supports: a) - with pin insulators 6-10 kV; b) - 35 kV;
c) - 110 kV; d) - 220 kV
Traverses of single-column reinforced concrete supports are galvanized metal.
The service life of reinforced concrete and metal galvanized or periodically painted supports is long and reaches 50 years or more.
