Graphic representation of metal supports. Electricity is the main thing. Unified system of technological documentation

All objects on the ground, the situation and characteristic forms of relief are displayed on topographic plans by symbols.

Conventions for topographic surveys

There are four main types into which conventional signs are divided:

1. Explanatory captions.
2. Linear symbols.
3. Area (contour).
4. Non-scale.

Explanatory captions are used to indicate additional characteristics depicted objects: near a river, indicate the speed of the current and its direction, near a bridge - the width, length and its load capacity, near roads - the nature of the surface and the width of the roadway itself, etc.

Linear symbols (symbols) are used to display linear objects: power lines, roads, product pipelines (oil, gas), communication lines, etc. The width shown on the topoplan of linear objects is off-scale.

Contour or area symbols represent those objects that can be displayed in accordance with the scale of the map and occupy a certain area. The contour is drawn with a thin solid line, dashed, or depicted as a dotted line. Formed outline filled in with symbols (meadow vegetation, woody vegetation, garden, vegetable garden, bushes, etc.).

To display objects that cannot be expressed on a map scale, off-scale symbols are used, and the location of such an off-scale object is determined by its characteristic point. For example: the center of a geodetic point, the base of a kilometer pole, the centers of radio, television towers, pipes of factories and factories.

In topography, displayed objects are usually divided into eight main segments (classes):

1. Relief
2. Mathematical basis
3. Soils and vegetation
4. Hydrography
5. Road network
6. Industrial enterprises
7. Settlements,
8. Signatures and borders.

Collections of symbols for maps and topographic plans of various scales are created in accordance with this division into objects. Approved by state organs, they are the same for all topographic plans and are required when drawing any topographical surveys (topographic surveys).

Frequently encountered symbols in topographic surveys:

State points geodetic network and concentration points

- Land use and allotment boundaries with boundary signs at turning points

- Buildings. The numbers indicate the number of floors. Explanatory captions are given to indicate the fire resistance of the building (zh - residential non-fire-resistant (wooden), n - non-residential non-fire resistant, kn - stone non-residential, kzh - stone residential (usually brick), smzh and smn - mixed residential and mixed non-residential - wooden buildings with thin brick veneer or with floors built from different materials(the first floor is brick, the second is wooden)). The dotted line shows a building under construction.

- Slopes. Used to display ravines, road embankments and other artificial and natural landforms with sudden elevation changes

- Power transmission lines and communication lines. Legend repeat the cross-sectional shape of the pillar. Round or square. Have iron concrete pillars There is a dot in the center of the symbol. One arrow in the direction of electrical wires - low-voltage, two - high-voltage (6 kV and above)

- Underground and above-ground communications. Underground - dotted line, aboveground - solid line. The letters indicate the type of communication. K - sewerage, G - gas, N - oil pipeline, V - water supply, T - heating main. Additional explanations are also given: Number of wires for cables, gas pipeline pressure, pipe material, their thickness, etc.

- Various area objects with explanatory captions. Wasteland, arable land, construction site, etc.

- Railways

- Car roads. The letters indicate the coating material. A - asphalt, Sh - crushed stone, C - cement or concrete plates. On unpaved roads, the material is not indicated, and one of the sides is shown as a dotted line.

- Wells and wells

- Bridges over rivers and streams

- Horizontals. Serve to display the terrain. They are lines formed by cutting the earth's surface parallel planes at regular intervals of height change.

- Height marks of characteristic points of the area. Typically in the Baltic height system.

- Various woody vegetation. The predominant species of tree vegetation is indicated, average height trees, their thickness and distance between trees (density)

- Separate trees

- Shrubs

- Various meadow vegetation

- Swampy conditions with reed vegetation

- Fences. Fences made of stone and reinforced concrete, wood, picket fences, chain-link mesh, etc.

Commonly used abbreviations in topographic surveys:

Buildings:

N - Non-residential building.

F - Residential.

KN - Stone non-residential

KZH - Stone residential

PAGE - Under construction

FUND. - Foundation

SMN - Mixed non-residential

CSF - Mixed Residential

M. - Metal

development - Destroyed (or collapsed)

gar. - Garage

T. - Toilet

Communication lines:

3 ave. - Three wires on a power pole

1 cab. - One cable per pole

b/pr - without wires

tr. - Transformer

K - Sewerage

Cl. - Storm sewerage

T - Heating main

N - Oil pipeline

cab. - Cable

V - Communication lines. Number of cables, for example 4V - four cables

n.d. - Low pressure

s.d. - Medium pressure

e.d. - High pressure

Art. - Steel

chug - Cast iron

bet. - Concrete

Area symbols:

page pl. - Construction site

og. - Vegetable garden

empty - Wasteland

Roads:

A - Asphalt

Ш - Crushed stone

C - Cement, concrete slabs

D - Wooden covering. Almost never occurs.

dor. zn. - Road sign

dor. decree. - Road sign

Water bodies:

K - Well

well - Well

art.well - artesian well

vdkch. - Water pump

bass. - Pool

vdhr. - Reservoir

clay - Clay

Symbols may differ on plans of different scales, so to read a topoplan it is necessary to use symbols for the appropriate scale.

How to correctly read symbols on topographic surveys

Let's consider how to correctly understand what we see on a topographical survey on specific example and how they will help us .

Below is a 1:500 scale topographic survey of a private house with a plot of land and the surrounding area.

In the upper left corner we see an arrow with the help of which it is clear how the topographic survey is oriented towards the north. On a topographic survey, this direction may not be indicated, since by default the plan should be oriented with its top part to the north.

The nature of the relief in the survey area: the area is flat with a slight decline to the south. The difference in elevation marks from north to south is approximately 1 meter. Height itself southern point 155.71 meters, and the northernmost 156.88 meters. To display the relief, elevation marks were used, covering the entire topographic survey area and two horizontal lines. The upper one is thin with an elevation of 156.5 meters (not indicated on the topographic survey) and the one located to the south is thicker with an elevation of 156 meters. At any point lying on the 156th horizontal line, the mark will be exactly 156 meters above sea level.

The topographic survey shows four identical crosses located at equal distances in the shape of a square. This is a coordinate grid. They serve to graphically determine the coordinates of any point on a topographic survey.

Next, we will sequentially describe what we see from north to south. In the upper part of the topoplan there are two parallel dotted lines with the inscription between them “Valentinovskaya St.” and two letters “A”. This means that we see a street called Valentinovskaya, the roadway of which is covered with asphalt, without a curb (since these are dotted lines. Solid lines are drawn with the curb, indicating the height of the curb, or two marks are given: the top and bottom of the curb).

Let us describe the space between the road and the fence of the site:

1. A horizontal line runs through it. The relief decreases towards the site.
2. In the center of this part of the survey there is a concrete power line pole, from which cables with wires extend in the directions indicated by the arrows. Cable voltage 0.4 kV. There is also a street lamp hanging on the pole.
3. To the left of the pillar we see four broad-leaved trees (this could be oak, maple, linden, ash, etc.)
4. Below the pillar, parallel to the road with a branch towards the house, an underground gas pipeline is laid (yellow dotted line with the letter G). The pressure, material and diameter of the pipe are not indicated on the topographic survey. These characteristics are clarified after agreement with the gas industry.
5. Two short parallel segments found in this topographic survey area are a symbol of grass vegetation (forbs)

Let's move on to the site itself.

The facade of the site is fenced with a metal fence more than 1 meter high with a gate and wicket. The facade of the left (or right, if you look at the site from the street) is exactly the same. The facade of the right plot is fenced wooden fence on a stone, concrete or brick foundation.

Vegetation on the site: lawn grass with free-standing pine trees (4 pcs.) and fruit trees(also 4 pcs.).

There is a concrete pole on the site with a power cable from the pole on the street to the house on the site. An underground gas branch runs from the gas pipeline route to the house. Underground water supply brought to the house from the neighboring plot. The fencing of the western and southern parts of the site is made of chain-link mesh, the eastern - of metal fence more than 1 meter high. In the southwestern part of the site, part of the fencing of neighboring sites made of chain-link mesh and a solid wooden fence is visible.

Buildings on the site: In the upper (northern) part of the site there is a residential one-story wooden house. 8 is the house number on Valentinovskaya Street. The floor level in the house is 156.55 meters. In the eastern part of the house there is a terrace with a wooden closed porch. In the western part, on the neighboring plot, there is a destroyed extension to the house. There is a well near the northeast corner of the house. In the southern part of the site there are three wooden non-residential buildings. A canopy on poles is attached to one of them.

Vegetation in neighboring areas: in the area located to the east - woody vegetation, to the west - grass.

On the site located to the south, a residential one-story wooden house is visible.

This way help to obtain a fairly large amount of information about the territory in which the topographic survey was carried out.

And finally, this is what this topographic survey looks like applied to an aerial photograph:

People who do not have special education in the field of geodesy or cartography may not understand the crosses depicted on maps and topographic plans. What kind of symbol is this?

This is the so-called coordinate grid, the intersection of whole or exact values coordinates Coordinates used on maps and topoplans can be geographic or rectangular. Geographic coordinates are latitude and longitude, rectangular coordinates are distances from the conventional origin in meters. For example, state cadastral registration is carried out in rectangular coordinates and for each region its own system of rectangular coordinates is used, which differs in its conditional origin in different regions of Russia (for the Moscow region the MSK-50 coordinate system is adopted). For maps covering large areas it is usually used geographical coordinates(latitude and longitude, which you could also see in GPS navigators).

Topographic survey or toposurvey is carried out in a rectangular coordinate system and the crosses that we see on such a topoplan are the intersections of circular coordinate values. If there are two topographic surveys of neighboring areas in the same coordinate system, they can be combined using these crosses and get a topographic survey for two areas at once, from which more complete information about the adjacent territory can be obtained.

Distance between crosses on topographic survey

In accordance with the rules and regulations, they are always located at a distance of 10 cm from each other and form regular squares. By measuring this distance on a paper version of the topographic survey, you can determine whether the scale of the topographic survey is maintained when printing or photocopying the source material. This distance should always be 10 centimeters between adjacent crosses. If it differs significantly, but not by an integer number of times, then such material cannot be used, since it does not correspond to the declared scale of the topographic survey.

If the distance between the crosses differs by several times from 10 cm, then most likely such a topographic survey was printed for some tasks that do not require adherence to the original scale. For example: if the distance between crosses on topographic survey 1:500 scale - 5cm, which means it was printed at a scale of 1:1000, distorting all the symbols, but at the same time reducing the size of the printed material, which can be used as an overview plan.

Knowing the scale of the topographic survey, you can determine what distance in meters on the ground corresponds to the distance between adjacent crosses on the topographic survey. So for the most commonly used topographic survey scale of 1:500, the distance between the crosses corresponds to 50 meters, for a scale of 1:1000 - 100 meters, 1:2000 - 200 meters, etc. This can be calculated knowing that between crosses on topographic survey 10 cm, and the distance on the ground in one centimeter of topographic survey in meters is obtained by dividing the denominator of the scale by 100.

It is possible to calculate the scale of topographic survey using crosses (coordinate grid) if the rectangular coordinates of neighboring crosses are indicated. To calculate, it is necessary to multiply the difference in coordinates along one of the axes of neighboring crosses by 10. Using the example of the topographic survey given below, in this case we will get: (2246600 - 2246550)*10= 500 ---> The scale of this survey is 1:500 or in one centimeter 5 meters. You can also calculate the scale, if it is not indicated on the topographic survey, using a known distance on the ground. For example, by the known length of a fence or the length of one of the sides of a house. To do this, divide the known length on the ground in meters by the measured distance of this length on a topographic survey in centimeters and multiply by 100. Example: the length of the wall of a house is 9 meters, this distance measured with a ruler on a topographic survey is 1.8 cm. (9/1.8) * 100 =500. Topographic scale - 1:500. If the distance measured on the topographic survey is 0.9 cm, then the scale is 1:1000 ((9/0.9)*100=1000)

The use of crosses in topographic surveys

Size crosses on topographic survey should be 1cm X 1cm. If the crosses do not correspond to these dimensions, then most likely the distance between them is not maintained and the scale of the topographic survey is distorted. As has already been written, using crosses, if topographic surveys are performed in one coordinate system, it is possible to combine topographic surveys of neighboring territories. Designers use crosses on topographic surveys to link objects under construction. For example, to set out the axes of buildings, the exact distances along the coordinate axes to the nearest cross are indicated, which makes it possible to calculate the future exact location of the designed object on the ground.

Below is a fragment of a topographic survey with the indicated values ​​of rectangular coordinates on the crosses.

Topographic survey scale

Scale is the ratio of linear dimensions. This word came to us from German language, and is translated as “measuring stick”.

What is a survey scale?

In geodesy and cartography, the term scale is understood as the ratio of the real size of an object to the size of its image on a map or plan. The scale value is written as a fraction with one in the numerator, and a number in the denominator indicating how many times the reduction was made.

Using the scale, you can determine which segment on the map the distance measured on the ground will correspond to. For example, moving one centimeter on a map with a scale of 1:1000 will be equivalent to ten meters covered on the ground. Conversely, every ten meters of terrain is a centimeter of a map or plan. The larger the scale, the more detailed the map, the more fully it displays the terrain objects plotted on it.

Scale– one of the key concepts topographic survey. The variety of scales is explained by the fact that each type of it, solution-oriented specific tasks, allows you to obtain plans of a certain size and generalization. For example, large-scale terrestrial surveying can provide a detailed display of the terrain and objects located on the ground. It is done during land management work, as well as during engineering and geodetic surveys. But it will not be able to show objects over as large an area as small-scale aerial photography.

The choice of scale primarily depends on the degree of detail of the map or plan required in each specific case. The larger the scale used, the higher the requirements for the accuracy of the measurements made. And the more experience the performers and specialized enterprises performing this survey should have.

Types of scale

There are 3 types of scale:

Named;

Graphic;

Numerical.

Topographic survey scale 1:1000 used in the design of low-rise construction and engineering surveys. It is also used for drawing up working drawings of various industrial facilities.

Smaller scale 1:2000 suitable, for example, for detailing individual sections of populated areas - cities, towns, rural areas. It is also used for projects of fairly large industrial buildings.

To scale 1:5000 draw up cadastral plans and general city plans. It is indispensable when designing railways and highways, laying communication networks. It is taken as a basis when drawing up small-scale topographic plans. Smaller scales, starting from 1:10000, are used for plans of the largest settlements - cities and towns.

But the greatest demand is for scale topographic surveys 1:500 . The range of its use is quite wide: from master plan construction site, to above-ground and underground engineering communications. Larger scale work is required only in landscape design, where ratios 1:50, 1:100 and 1:200 are required for detailed description terrain - isolated trees, bushes and other similar objects.

For topographic surveys at a scale of 1:500, the average errors of contours and objects should not exceed 0.7 millimeters, no matter how complex the terrain and relief may be. These requirements are determined by the specific area of ​​application, which includes:

utility plans;

drawing up very detailed plans for industrial and utility structures;

improvement of the area adjacent to the buildings;

layout of gardens and parks;

landscaping of small areas.

Such plans depict not only relief and vegetation, but also water bodies, geological wells, landmarks and other similar structures. One of the main features of this large-scale topographic survey is the placement of communications, which must be coordinated with the services that operate them.

Do-it-yourself topographic survey

Is it possible to carry out a topographic survey of your own site with your own hands, without involving a specialist in the field of geodesy? How difficult is it to carry out topographic surveys on your own?

In case a topographic survey is necessary to obtain any official documents, such as a building permit, ownership or lease land plot or receiving technical specifications for connection to gas, electricity or other communications, you will not be able to provide DIY topographic survey. In this case, topographic survey is an official document, the basis for further design, and only specialists who have a license to carry out geodetic and cartographic work or are members of a self-regulatory organization (SRO) corresponding to these types of work have the right to perform it.

Execute do-it-yourself topographic survey without special education and work experience it is almost impossible. Topographic survey is a rather technically complex product that requires knowledge in the field of geodesy, cartography and the availability of special expensive equipment. Possible errors in the resulting topoplan can lead to serious problems. For example, an incorrect determination of the location of a future structure due to poor-quality topographic survey can lead to a violation of fire safety and building codes and, as a result, to a possible court decision to demolish the structure. Topographic survey with gross errors can lead to incorrect location of the fence, violating the rights of neighbors of your land and ultimately to its dismantling and significant additional costs for its construction in a new location.

In what cases and how can you do topographic surveys yourself?

The result of the topographic survey is detailed plan terrain, which displays the relief and detailed situation. Special geodetic equipment is used to plot objects and terrain on the plan.
Devices and tools that can be used to perform topographic surveys:

theodolite

total station

• high-precision geodetic GPS/GLONASS receiver

  3D laser scanner

Theodolite is the most cheap option equipment. The cheapest theodolite costs about 25,000 rubles. The most expensive of these devices is a laser scanner. Its price is measured in millions of rubles. Based on this and the prices for topographic surveys, it does not make sense to purchase your own equipment to perform topographic surveys with your own hands. There remains the option of renting equipment. The cost of renting an electronic total station starts from 1000 rubles. in a day. If you have experience in topographic surveys and working with this equipment, then it makes sense to rent an electronic total station and do the topographic survey yourself. Otherwise, without experience, you will spend quite a lot of time studying complex equipment and work technology, which will lead to significant rental costs that exceed the cost of performing this type of work by an organization that has a special license.

For the design of underground communications on the site important has the character of a relief. Incorrect determination of the slope can lead to undesirable consequences when laying sewerage. Based on the above, the only possible variant do-it-yourself topographic surveys this is a compilation simple plan on a site with existing buildings for simple landscaping. In this case, if the plot is registered in the cadastral register, a cadastral passport with form B6 can help. The exact dimensions, coordinates and rotation angles of the site boundaries are indicated there. The most difficult thing when taking measurements without special equipment is determining the angles. Available information about the boundaries of the site can be used as a basis for constructing a simple plan for your site. A tape measure can serve as a tool for further measurements. It is desirable that its length be sufficient for measuring the diagonals of the section, otherwise, when measuring the lengths of lines in several steps, errors will accumulate. Measurements with a tape measure to draw up a site plan can be carried out if there are already established boundaries of your site and they are fixed with boundary signs or coincide with the site fence. In this case, to plot any objects on the plan, several measurements are taken of the lengths of lines from boundary signs or corners of the site. The plan is drawn up electronically or on paper. For paper version It's better to use graph paper. The boundaries of the site are drawn on the plan and used as a basis for further construction. The distances measured with a tape measure are laid off from the plotted corners of the site and at the intersection of the radii of the circles corresponding to the measured distances, the location of the required object is obtained. The plan obtained in this way can be used for simple calculations. For example, calculating the area occupied by a vegetable garden, preliminary calculation of the amount of building materials needed for additional decorative fences or laying garden paths.

Taking into account all of the above, we can conclude:

If a topographic survey is required to obtain any official documents (building permit, cadastral registration, urban planning plan, planning organization diagram) or to design a residential building, its implementation must be entrusted to an organization that has the appropriate license or is a member of a self-regulatory organization (SRO). In this case, done do it yourself topographic survey has no legal force and possible mistakes if carried out by a non-professional, it can lead to catastrophic consequences. The only possible option do-it-yourself topographic surveys This is drawing up a simple plan for solving simple problems on your personal property.

Reinforced concrete power transmission line supports used in the installation of overhead power lines (VL and VLI) in populated areas and in uninhabited areas. Reinforced concrete supports are made on the basis of standard concrete pillars: SV 95-2V, SV 95-3V, SV110-1A, SV 110-3.5A, SV110-5A.

Reinforced concrete power transmission line supports - classification by purpose

The classification of reinforced concrete supports by purpose does not go beyond the types of supports standardized in GOST and SNiP. Read in detail: Types of supports by purpose, but here I will briefly remind you.

Intermediate concrete supports needed to support cables and wires. They are not subject to longitudinal or angular tension loads. (marking P10-3, P10-4)

Anchor concrete supports provide retention of wires during their longitudinal tension. Anchor supports must be installed at the intersection of power lines with railways and other natural and engineering barriers.

Corner supports are placed at the turns of the power line route. At small angles (up to 30°), where the tension load is not large and if there is no change in the cross-section of the wires, angular intermediate supports (IP) are installed. At large rotation angles (more than 30°), corner anchor supports (CA) are installed. At the end of the power line, anchors, also known as end supports, are placed (A). For branches to subscribers, branch anchor supports (OA) are installed.

Marking of concrete supports

It is worth focusing on the markings of the supports. In the previous paragraph I used the markings for the 10-2 supports. Let me explain how to read the markings of the supports. Reinforced concrete supports are marked as follows.

• The first two letters indicate the purpose of the support: P (intermediate) UP (intermediate corner), UA (corner anchor), A (anchor-end), OA (branch support), UOA (corner branch anchor).
• The second number means for which power transmission line the support is intended: the number “10” is a 10 kV power line.
• The third number after the dash is the standard size of the support. The number “1” is a 10.5 meter support, based on the SV-105 pillar. The number “2” is a support based on the SV-110 pillar. Detailed standard sizes are in the tables at the bottom of the article.

Reinforced concrete support structures

Reinforced concrete support structures also do not go beyond standard support structures.

• Portal supports with guy ropes – two parallel supports are supported by guy ropes;
• Free-standing portal supports with crossbars;
• Free-standing supports;
• Supports with guys.

The use of supports must comply with design calculations. For calculations, various normative tables are used, the volume of which occupies several volumes.

Concrete supports according to the number of chains held

If the support crossbars allow you to hook only one line of electric power, it is called single-chain (crossbar on one side). If the crossbar is on both sides, then the support is double-chain. If you can hang many lines of wires, then this is a multi-circuit support.

class="eliadunit">

Installation of concrete supports

Calculation of supports is carried out by SNiP 2.02.01-83 and “Guide to the design of power lines and power line foundations...”. The calculation is based on deformation and bearing capacity.

To secure the intermediate support type P10-3(4), you need to drill a cylindrical pit with a diameter of 35-40 cm, to a depth of 2000 -25000 mm. An installation bolt is not needed for such a support.

Anchor corner and anchor branch supports, are usually mounted with mounting crossbars. Please note that the crossbars can be placed on the lower edge of the support and strut, buried in the ground and/or on the upper edge of the support, along the top of the pit. The crossbars provide additional stability to the support. The depth of installation of the support depends on the freezing of the soil. Usually 2000-2500 mm.

Grounding of concrete supports

Thanks to the design of the support posts, grounding the supports is very convenient. In the racks of CB supports, in the factory during their manufacture, the top and bottom of the rack are metal fittings 10 mm in diameter. This reinforcement runs inextricably along the entire length of the rack. It is this reinforcement that serves to ground reinforced concrete supports.

Depending on the method of hanging wires, overhead line (OHL) supports are divided into two main groups:

A) intermediate supports, on which the wires are fixed in supporting clamps,

b) anchor type supports, used for tensioning wires. On these supports, the wires are secured in tension clamps.

The distance between supports (power lines) is called span, and the distance between anchor-type supports is called anchored area(Fig. 1).

According to the intersection of some engineering structures, for example, public railways, must be performed on anchor-type supports. At the angles of rotation 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 area overhead line

Intermediate straight supports installed on straight sections of the line. On intermediate supports with hanging insulators, the wires are secured in supporting garlands hanging vertically; on intermediate supports with pin insulators, the wires are secured with wire knitting. In both cases, intermediate supports perceive horizontal loads from wind pressure on the wires and on the support, and vertical loads from the weight of the wires, insulators and the own weight of the support.

With unbroken wires and cables, intermediate supports, as a rule, do not take the horizontal load from the tension of the wires and cables in the direction of the line and therefore can be made more lightweight design than other types of supports, for example, end supports that absorb 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 are installed at the angles of rotation of the line with wires suspended in supporting garlands. In addition to the loads acting on intermediate straight supports, intermediate and anchor corner supports also absorb loads from the transverse components of the tension of wires and cables.

At transmission line rotation angles 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°. For large rotation angles, install anchor corner supports.

Rice. 2. Intermediate supports for overhead lines

Anchor supports. On lines with suspended insulators, the wires are secured in the clamps of tension garlands. These garlands are like a continuation of the wire and transfer its tension to the support. On lines with pin insulators, the wires are secured to anchor supports with reinforced ties 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 equal tensions, the horizontal longitudinal loads from the wires are balanced and the anchor support works in the same way as an 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 horizontal transverse and vertical loads, the support will also be subject to horizontal longitudinal load. When installing anchor supports at corners (at the turning points of the line), the anchor corner supports also take the load from the transverse components of the tension of wires and cables.

End supports are installed at the ends of the line. Wires extend from these supports and are suspended on substation portals. When hanging wires on the line before the construction of the substation is completed, the end supports perceive full one-sided tension.

In addition to the listed types of supports, special supports are also used on lines: transpositional, used to change the order of arrangement of wires on supports, branch lines - to make branches from the main line, supports large crossings across rivers and water bodies, etc.

The main type of supports on overhead lines are intermediate, the number of which is usually 85-90% total number support

Based on their design, supports can be divided into: free-standing And guyed supports. Guys are usually made of steel cables. Wooden, steel and reinforced concrete supports are used on overhead lines. Support designs made of aluminum alloys have also been developed.
Overhead line support structures

1. Wooden support of the 6 kV LOP (Fig. 4) - single-column, intermediate. Made from pine, sometimes larch. The stepson is made of impregnated pine. For 35-110 kV lines, wooden U-shaped two-post supports are used. Additional items support structures: hanging garland with hanging clamp, traverse, braces.
2. Reinforced concrete supports are made as single-column free-standing ones, without guys or with guys on the ground. The support consists of a post (trunk) made of centrifuged reinforced concrete, a traverse, a lightning protection cable with a grounding conductor on each support (for lightning protection of the line). Using a grounding pin, the cable is connected to a ground electrode (a conductor in the form of a pipe driven into the ground next to the support). The cable serves to protect lines from direct lightning strikes. Other elements: stand (barrel), rod, traverse, cable support.
3. Metal (steel) supports (Fig. 5) are used at voltages of 220 kV and more.

Types of overhead line supports

In the production of metal structures for power lines The following types of overhead line supports are distinguished:

intermediate power line supports,

power line anchor supports ,

power line corner supports and special metal products for power lines. The types of overhead power line structures that are the most numerous on all power lines are intermediate supports, which are designed to support wires on straight sections of the route. All high-voltage wires are attached to power line cross-arms through supporting garlands of insulators and other structural elements of overhead power lines. In normal mode, overhead line supports of this type take loads from the weight of adjacent half-spans of wires and cables, the weight of insulators, linear reinforcement and individual elements of the supports, as well as wind loads caused by wind pressure on the wires, cables and the metal structure of the power line itself. In emergency mode, the structures of intermediate power transmission line supports must withstand the stresses that arise when one wire or cable breaks.

Distance between two adjacent intermediate supports of overhead lines called the intermediate span. Overhead line corner supports can be intermediate or 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 the loads acting on the usual intermediate elements of power lines, perceive the total forces 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 installation conditions of the lines, the requirements for the intersections 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 corner supports and as terminal wires from which the line wires go to the switchgear of a substation or station. On lines running in populated areas, the number of power line anchor corner elements also increases. The overhead line wires are secured through tension garlands of insulators. In normal mode for these power line supports , in addition to the loads indicated for the intermediate elements of the molding, the difference in tension along the wires and cables in adjacent spans and the resultant of the tension forces along the wires and cables act. Typically, 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, power line anchor posts must withstand the break of two wires or cables. Distance between two adjacent power line anchor supports called an anchor span. Branch elements of power transmission lines are designed to make branches from main overhead lines when it is necessary to supply power to consumers located at some distance from the route. Cross elements are used to cross overhead line wires in two directions. Overhead line end posts are installed at the beginning and end of the overhead line. They perceive forces directed along the line created by the normal one-way tension of the wires. For overhead lines, power line anchor supports are also used, which have increased strength and a more complex design compared to the types of stands listed above. For overhead lines with voltage up to 1 kV, reinforced concrete racks are mainly used.

What types of power line supports are there? Classification of varieties

They are classified according to the method of fixation in the ground:

Overhead line supports installed directly into the ground - Power line supports installed on foundations Types of power line supports by design:

Free-standing power transmission towers - Posts with guys

Power line supports are classified according to the number of circuits:

Single-chain - Double-chain - Multi-chain

Unified power line supports

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 line supports

For metal and reinforced concrete supports of 10 - 330 kV overhead lines, the following designation system has been adopted.

P, PS - intermediate supports

PVS - intermediate supports with internal connections

PU, PUS - intermediate corner

PP - intermediate transition

U, US - anchor-angular

K, KS - end

B - reinforced concrete

M - Polyhedral

How are overhead line supports marked?

The numbers after the letters in the marking indicate the voltage class. The presence of the letter “t” indicates a cable stand with two cables. The number separated by a hyphen in the marking of overhead line supports indicates the number of circuits: odd, for example, one in the numbering of a power line support is a single-circuit line, even number in numbering - two and multi-chain. The number separated by “+” in the numbering means the height of the attachment to the base support (applicable to metal ones).

For example, symbols of overhead line supports: U110-2+14 - Metal anchor-corner double-chain support with a stand of 14 meters PM220-1 - Intermediate metal multifaceted single-chain support U220-2t - Metal anchor-corner double-chain support with two cables PB110-4 - Intermediate reinforced concrete double-chain support

Overhead power lines. Support structures.

Supports and foundations for overhead power lines with voltage 35-110 kV have a significant share both in terms of material consumption and in cost terms. Suffice it to say that the cost of installed support structures on these overhead lines is, as a rule, 60-70% of the total cost of constructing overhead power lines. For lines located on industrial enterprises and immediately adjacent territories, 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 supports are divided into anchor and intermediate. The supports of these two groups differ in the way the wires are suspended.

Anchor supports completely absorb the tension of wires and cables in spans adjacent to the support, i.e. used for tensioning wires. The wires are suspended from these supports using hanging garlands. Anchor-type supports can be of normal or lightweight design. Anchor supports are much more complex 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. The wires are suspended on intermediate supports using supporting garlands of insulators, Fig. 1.

Rice. 1. 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 carried out terminal and transposition supports. Intermediate and anchor supports can be straight and angular.

End anchor supports installed at the line exiting the power plant or at the approaches to the substation are in the worst conditions. These supports experience one-sided pull of all wires from the line side, since the pull from the substation portal is insignificant.

Intermediate lines poles are installed on straight sections of overhead power lines to support the wires. An intermediate support is cheaper and easier to manufacture than an anchor support, since under normal conditions it does not experience forces along the line. Intermediate supports make up at least 80-90% of the total number of overhead line supports.

Corner supports are installed at the turning points of the line. At line rotation angles of up to 20°, anchor-type corner supports are used. When the angle of rotation of the power line is more than 20 o - intermediate corner supports.

Used on overhead power lines special supports following types: transpositional– to change the order of wires on supports; branch– to make 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 line chain the same. At the same time, the relative position of the wires in relation to each other on the supports is successively changed. However, this 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. Transposition cycle of single-circuit line wires

Depending on the number of chains suspended from the supports, the supports may be single-chain 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 locations of wires on supports are shown schematically in Fig. 3.

Rice. 3. The most common locations of wires and cables on supports:

a – location along the vertices of the triangle; b - horizontal arrangement; c – reverse tree arrangement

The possible location of lightning protection cables is also indicated there. The arrangement of 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 supports and on higher voltage lines on other supports. For double-chain supports, it is more convenient from an installation point of view to arrange the wires in a “reverse tree” type, 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. The most common are pine supports and somewhat less common are larch supports. The advantages of these supports are their low cost (if local wood is available) and ease of manufacture. The main disadvantage is wood rotting, especially intense at the point of contact of the support with the soil.

Metal supports made of special grades of steel for lines of 35 kV and above, they 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 a long service life. Install metal supports on reinforced concrete foundations. These supports, according to the design of the support body, can be classified into two main schemes - tower or single-post, rice. 4, and portal, rice. 5.a, according to the method of fastening to the foundations - k free-standing supports, fig. 4 and 6, and guyed supports, rice. 5.a, b, c.

On metal supports with a height of 50 m or more, stairs with guardrails reaching the top of the support must be installed. In this case, each section of supports must have platforms with fences.

Rice. 4. Intermediate metal support for single circuit line:

1 – wires; 2 – insulators; 3 – lightning protection cable; 4 – cable support; 5 – support traverses; 6 – support stand; 7 – support foundation

Rice. 5. Metal supports:

a) – intermediate single-circuit on guy wires 500 kV; b) – intermediate V-shaped 1150 kV; c) – intermediate support of 1500 kV DC overhead line; d) – elements of spatial lattice structures

Rice. 6. Metal free-standing double chain supports:

a) – intermediate 220 kV; b) – anchor corner 110 kV

Reinforced concrete supports are carried out for lines of all voltages up to 500 kV. To ensure the required density of concrete, vibration compaction and centrifugation are used. Vibration compaction is carried out using various vibrators. Centrifugation provides very good compaction of concrete and requires special machines - centrifuges. On overhead power lines of 110 kV and above, the support posts and 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 are widely used. They have a lower cost, but have 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

Crossbeams 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.

STATE STANDARD OF THE USSR UNION

UNIFIED SYSTEM OF TECHNOLOGICAL DOCUMENTATION

SUPPORTS, CLAMPS
AND INSTALLATION DEVICES.
GRAPHICAL SYMBOLS

GOST 3.1107-81
(C.T.CMEA 1803 -7 9)

STATE STANDARD OF THE USSR UNION

from 01.07.82

1. This standard establishes graphic designations of supports, clamps and installation devices used in technological documentation. The standard fully complies with ST SEV 1803-7 9. 2. To depict the designation of supports, clamps and installation devices, a solid thin line should be used in accordance with GOST 2.303-68. 3. Designations of supports (conditional) are given in table. 1.

Table 1

table 2

Table of persons 3

Table 4

Table 5

ANNEX 1

Information

Examples of marking supports, clamps and installation devices on diagrams