Section 2. Sewerage of electricity

Overhead power lines with voltage above 1 kV. Crossing and approaching overhead lines with communication, signaling and wire broadcasting facilities

Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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2.5.231. The intersection of overhead lines with voltage up to 35 kV with LS and LPV must be performed according to one of the following options:

1) wires of overhead lines and underground cable LS * and LPV;

2) wires of overhead lines and air cable of drugs and LPV;

3) underground cable insert in overhead lines and uninsulated wires LS and LPV;

4) wires of overhead lines and uninsulated wires of LS and LPV.

* In this chapter, communication cables include metal and optical cables with metal elements.

2.5.232. The intersection of overhead lines with voltage up to 35 kV with uninsulated wires LS and LPV can be used in the following cases:

1) if it is impossible to lay either an underground cable for LS and LPV, or an overhead line cable;

2) if the use of a cable insert in the LAN will lead to the need to install an additional or transfer the previously installed amplifying point of the LAN;

3) if, when using a cable insert in a LPV, the total length of cable inserts in a line exceeds the allowable values;

4) if suspension insulators are used on the overhead line. At the same time, overhead lines at the intersection with uninsulated wires LS and PV are made with increased mechanical strength of wires and supports (see 2.5.240).

2.5.233. The intersection of 110-500 kV overhead lines with LS and LPV must be performed according to one of the following options:

1) wires of overhead lines and underground cable LS and LPV;

2) wires of overhead lines and uninsulated wires of LS and LPV.

2.5.234. The intersection of the 750 kV overhead line with the LS and LPV is carried out by the underground cable of the LS and LPV. If it is impossible to lay an underground cable of the LS and LPV in a cramped, difficult mountainous area, it is allowed to cross the LS and LPV with a 750 kV overhead line with uninsulated wires, but the clear distance from the tops of the LS and LPV supports to the non-deflected wires of the overhead line must be at least 30 m.

2.5.235. When crossing overhead lines 110-500 kV with overhead wires LS and LPV, cable inserts should not be used if:

1) the use of a cable insert in the LAN will lead to the need to install an additional amplifying point on the LAN, and the refusal to use this cable insert will not lead to an increase in the interfering effect of the overhead line on the LAN in excess of permissible standards;

2) the use of a cable insert in the LPV will lead to an excess of the total allowable length of the cable inserts in the line, and the rejection of this cable insert will not increase the interfering effect of the overhead line on the LPV in excess of the permissible value.

2.5.236. In the span of the intersection of LS and LPV with overhead lines up to 750 kV, which provide channels for high-frequency communication and telemechanics with equipment operating in the same frequency spectrum as the equipment of LS and LPV and having a power per channel:

1) more than 10 W - LS and LPV must be made by underground cable inserts. The length of the cable insert is determined by calculating the interfering effect, while the horizontal distance from the base of the cable support of the LS and LPV to the projection of the extreme wire of the overhead line on the horizontal plane must be at least 100 m;

2) from 5 to 10 W - the need to use a cable insert in the LS and LPV or to take other means of protection is determined by calculating the interfering effect. At the same time, in the case of using a cable insert, the clear distance from the undeflected wires of the overhead line up to 500 kV to the tops of the cable poles of the LS and LPV must be at least 20 m, and from the undeflected wires of the 750 kV overhead line to the tops of the cable poles of the LS and LPV - at least 30m;

3) less than 5 W or if the high-frequency equipment of the overhead line operates in a mismatched frequency spectrum, or the LS and LPV are not sealed with high-frequency equipment - the use of a cable insert when crossing with overhead lines up to 750 kV is not required under the conditions of interfering influence. If the cable insert in the LS and LPV is not equipped under the conditions of interfering influence from the high-frequency channels of the overhead line, then the horizontal distance from the base of the cable support of the LS and LPV to the projection onto the horizontal plane of the extreme undeflected wire of the overhead line up to 330 kV must be at least 15 m. For overhead lines 500 kV, the clear distance from the extreme undeflected wires of the overhead line to the top of the cable supports of the LS and LPV must be at least 20 m, and for 750 kV overhead lines - at least 30 m.

2.5.237. Intersections of wires of overhead lines with overhead lines of city telephone communication are not allowed; these lines in the span of intersection with wires of overhead lines should be carried out only by underground cables.

2.5.238. When crossing overhead lines with an underground communication cable and PV (or with an underground cable insert), the following requirements must be observed:

1) the angle of intersection of an overhead line up to 500 kV with LS and LPV is not standardized, the angle of intersection of an overhead line of 750 kV with LS and LPV should be as close as possible to 90º, but not less than 45º;

2) the distance from the underground cables of the LS and LPV to the nearest ground electrode of the overhead line support with a voltage of up to 35 kV or its underground metal or reinforced concrete part must be at least:

• in populated areas - 3 m;
• in uninhabited areas - the distances given in Table. 2.5.26.

The distance from underground cables LS and LPV to the underground part of an ungrounded wooden pole of overhead lines with a voltage of up to 35 kV must be at least:

• in populated areas - 2 m, in cramped conditions the specified distance can be reduced to 1 m, provided that the cable is laid in a polyethylene pipe at a length of at least 3 m on both sides of the support;
• in an uninhabited area: 5 m - with an equivalent earth resistivity of up to 100 Ohm m; 10 m - with an equivalent earth resistivity of 100 to 500 Ohm m; 15 m - with an equivalent earth resistivity of 500 to 1000 Ohm m; 25 m - with an equivalent earth resistivity of more than 1000 Ohm m;

3) the distance from the underground cables of the LS and LPV to the nearest ground electrode of the support of the overhead line 110 kV and above and its underground part must be at least the values ​​\u2.5.26b\uXNUMXbgiven in Table. XNUMX;

4) when laying an underground cable (cable insert) in steel pipes, or when covering it with a channel, angle, or when laying it in a polyethylene pipe, closed on both sides from the ground, at a length equal to the distance between the wires of the overhead line plus 10 m s each side from the extreme wires for overhead lines up to 500 kV and 15 m for overhead lines 750 kV, it is allowed to reduce those indicated in table. 2.5.26 distances up to 5 m for overhead lines up to 500 kV and up to 10 m for 750 kV.

In this case, the metal sheaths of the cable should be connected to a pipe or other metal protective elements. This requirement does not apply to optical cables and cables with an external insulating conduit, including those with a metal sheath. The metal sheaths of the cable insert must be grounded at the ends. With a decrease in the distances between the cable and the overhead line supports, indicated in Table. 2.5.26, in addition to the above protection measures, it is necessary to provide additional protection against lightning strikes by contouring supports with cables in accordance with the requirements of regulatory documentation for the protection of cables from lightning strikes;

5) instead of using a channel, angle or steel pipe, it is allowed to use two steel cables with a cross section of 70 mm during the construction of a new overhead line, laid symmetrically at a distance of no more than 0,5 m from the cable and at a depth of 0,4 m. The cables must be extended on both sides at an angle of 45º to the route towards the overhead line support and grounded for a resistance of not more than 30 ohms. The ratios between the length of the cable outlet l and the resistance R of the grounding conductor must correspond to the values ​​Ki and Kd given in Table. 2.5.27;

6) in the span of the intersection of the overhead line with the LS and LPV, the fastening of the wires of the overhead line on the supports that limit the crossing span should be carried out using blind clamps that prevent the wires from falling to the ground in the event of their breakage in adjacent spans.

Table 2.5.26. The shortest distances from the underground cables of the LS (LPV) to the nearest ground electrode of the overhead line support and its underground part

Table 2.5.27. Resistance of grounding conductors when protecting the cable of the LS and LPV at the intersection with the overhead line *

* Protecting the cable from lightning strikes by contouring the overhead line supports or laying a protective cable in this case is also mandatory.

2.5.239. When crossing an underground cable insert in overhead lines up to 35 kV with uninsulated wires LS and LPV, the following requirements must be observed:

1) the angle of intersection of the underground cable insert of the overhead line with the LS and LPV is not standardized;

2) the distance from the underground cable insert to the ungrounded support of the LS and LPV must be at least 2 m, and to the grounded support of the LS (LPV) and its ground electrode - at least 10 m;

3) the horizontal distance from the base of the cable support of the overhead line, unsealed and sealed in non-coinciding and coinciding frequency spectra, depending on the power of the high-frequency equipment, to the projection of the wires of the LS and LPV should be selected in accordance with the requirements set forth in 2.5.236;

4) underground cable inserts in overhead lines must be carried out in accordance with the requirements given in Ch. 2.3 and 2.5.124.

2.5.240. When crossing wires of overhead lines with uninsulated wires of LS and LPV, the following requirements must be observed:

1) the angle of intersection of the wires of the overhead line with the wires of the LS and LPV should be as close as possible to 90º. For cramped conditions, the angle is not standardized;

2) the intersection should be chosen as close as possible to the overhead line support. At the same time, the horizontal distance from the nearest part of the overhead line support to the LS and LPV wires must be at least 7 m, and from the LS and LPV supports to the projection onto the horizontal plane of the nearest undeflected overhead line wire must be at least 15 m. Clear distance from the tops of the supports LS and PV to non-deflected wires of overhead lines should be at least: 15m - for overhead lines up to 330 kV, 20 m - for overhead lines 500 kV;

3) the location of the supports of the LS and LPV under the wires of the crossing overhead line is not allowed;

4) VL supports, limiting the span of the intersection with the LS and LPV, should be of the anchor type of lightweight construction from any material, both free-standing and on braces. Wooden supports must be reinforced with additional attachments or struts;

5) intersections can be performed on intermediate supports, provided that wires with a cross-sectional area of ​​\u120b\u2bthe aluminum part of at least XNUMX mmXNUMX are used on overhead lines;

6) VL wires should be located above the LS and LPV wires and should be multi-wire sections not less than those given in Table. 2.5.5;

7) wires LS and LPV in the span of the intersection should not have connections;

8) in the span of the intersection of overhead lines with LS and LPV on intermediate supports of overhead lines, the fastening of wires on supports should be carried out only with the help of insulators supporting garlands with blind clamps;

9) a change in the installation location of the supports of the LS and LPV, limiting the span of the intersection with the overhead line, is allowed, provided that the deviation of the average length of the crossing element on the LS and LPV will not exceed the values ​​\u2.5.28b\uXNUMXbspecified in Table. XNUMX;

10) the length of the spans of the LS and LPV at the intersection with the overhead line should not exceed the values ​​\u2.5.29b\uXNUMXbspecified in Table. XNUMX;

11) LS and LPV supports that limit the crossing span or adjacent to it and located on the side of the highway must be protected from vehicle collisions;

12) wires on the supports of the LS and LPV, limiting the span of the intersection with the overhead line, must have a double fastening: with a traverse profile - only on the upper traverse, with a hook profile - on the two upper chains;

13) the vertical distances from the wires of the overhead line to the crossed wires of the LS and LPV in the normal mode of the overhead line and in the event of a break in the wires in adjacent spans of the overhead line must be at least those given in table. 2.5.30.

Vertical distances are determined in the normal mode with the largest sag of wires (without taking into account their heating by electric current). In emergency mode, distances are checked for overhead lines with wires with a cross-sectional area of ​​\u185b\u2bthe aluminum part of less than 185 mm2 at an average annual temperature, without ice and wind. For overhead lines with wires with a cross-sectional area of ​​\uXNUMXb\uXNUMXbthe aluminum part of XNUMX mmXNUMX or more, an emergency check is not required.

With a difference in the heights of the attachment points of the LS and LPV wires on supports that limit the crossing span (for example, on slopes) with 35 kV overhead lines and above, the vertical distances determined from Table. 2.5.30 are subject to additional verification for the conditions for the deviation of the wires of the overhead line at the wind pressure determined in accordance with 2.5.56, directed perpendicular to the axis of the overhead line, and with the non-deflected position of the wires of the LS and LPV.

Distances between wires should be taken for the most unfavorable case.

When using ice melting on overhead lines, it is necessary to check the dimensions to the wires of the LS and LPV in the ice melting mode. These dimensions are checked at the temperature of the wire in the ice melting mode and should not be less than when the wire of the overhead line breaks in the adjacent span;

14) on wooden poles of overhead lines without a lightning protection cable, limiting the span of intersection with LS and LPV, with distances between the wires of intersecting lines less than those indicated in paragraph b) of Table. 2.5.30 protective devices must be installed on the overhead line. Protective devices must be installed in accordance with the requirements of 2.5.229. When installing the IP on the overhead line, automatic re-closing should be provided;

15) lightning rods should be installed on the wooden supports of the LS and LSW, limiting the crossing span, in accordance with the requirements specified in the regulatory documentation for LS and LSW.

Table 2.5.28. Permissible change in the installation location of the LS and LPV supports, limiting the span of the intersection with the overhead line

Table 2.5.29. Maximum allowable span lengths of LS and PV at the intersection with VL

* O - normal, N - normal, U - reinforced, OS - especially reinforced, line types - in accordance with the "Rules for the intersection of overhead communication lines and radio broadcasting networks with power lines".

Table 2.5.30. The smallest vertical distance from the wires of the overhead line to the wires of the LS and LPV

2.5.241. Joint suspension of wires of overhead lines and wires of LS and LPV on common supports is not allowed. This requirement does not apply to special optical cables that are suspended on overhead lines. These cables must comply with the requirements of this chapter and the rules for the design, construction and operation of fiber-optic communication lines on overhead power lines.

2.5.242. When approaching overhead lines with drugs and LPV, the distances between their wires and measures to protect against influence are determined in accordance with the rules for protecting wired communication devices, railway signaling and telemechanics from dangerous and interfering influence of power lines.

2.5.243. When approaching overhead lines with aerial LS and LPV, the smallest distances from the extreme non-deflected wires of the overhead line to the supports of the LS and LPV should be no less than the height of the highest support of the overhead line, and in sections of the cramped route, the distance from the extreme wires of the overhead line with the greatest deviation of their wind distances should be at least the values ​​indicated in the table. 2.5.31. At the same time, the clear distance from the nearest undeflected wire of the overhead line to the tops of the LS and LPV supports should be at least: 15 m - for overhead lines up to 330 kV, 20 m - for overhead lines 500 kV, 30 m - for overhead lines 750 kV.

The transposition step of the VL according to the condition of influence on the drugs and the LPV is not standardized.

The supports of the LS and LPV should be reinforced with additional supports or installed double if, when they fall, contact between the wires of the LS and LPV and the wires of the overhead line is possible.

Table 2.5.31. The smallest distances between the wires of the overhead line with the greatest deviation of them by the wind and the supports of the LS and LPV in a cramped route

2.5.244. When approaching overhead lines with pin insulators in areas with angles of rotation, with air LS and LPV, the distances between them must be such that the wire that has fallen off the corner support of the overhead line cannot be from the nearest wire of the LS and LPV at distances less than those given in Table. 2.5.31. If it is impossible to fulfill this requirement, the wires of the overhead lines that depart from the inside of the turn must have a double fastening.

2.5.245. When approaching overhead lines with underground cables LS and LPV, the smallest distances between them and protection measures are determined in accordance with the rules for protecting wired communication devices, railway signaling and telemechanics from the dangerous and interfering influence of power lines and recommendations for protecting optical cables with metal elements from the dangerous influence of lines transmission lines, electrified AC railways and power substations.

The smallest distances from the ground electrode and the underground part of the overhead line support to the underground cable LS and LPV must be at least those given in Table. 2.5.26.

2.5.246. Distances from overhead lines to antenna structures of transmitting radio centers should be taken according to Table. 2.5.32.

Table 2.5.32. The smallest distances from overhead lines to antenna structures of transmitting radio centers

2.5.247. The smallest distances of approach of the overhead line with the alignment of the radio relay line and radio relay stations outside the antenna directivity zone should be taken according to Table. 2.5.33. The possibility of crossing the overhead line with the alignment of the radio relay line is established during the design of the overhead line.

2.5.248. Distances from overhead lines to the boundaries of receiving radio centers and dedicated receiving points of radio coverage and local radio nodes should be taken according to Table. 2.5.33.

In the case of passing the route of the designed overhead line in the area where especially important receiving radio devices are located, the permissible approach is established individually in the process of designing the overhead line.

If the observance of the distances indicated in Table. 2.5.33, it is difficult, then in some cases their reduction is allowed (subject to the implementation of measures on overhead lines that ensure an appropriate reduction in interference). For each case in the process of designing overhead lines, a project of measures to comply with radio interference standards should be drawn up.

Distances from overhead lines to television centers and radio houses must be at least: 400 m - for overhead lines up to 20 kV, 700 m - for overhead lines 35-150 kV, 1000 m - for overhead lines 220-750 kV.

Table 2.5.33. The shortest distances from overhead lines to the boundaries of receiving radio centers, radio relay KB and VHF stations, dedicated receiving points of radio coverage and local radio nodes

See other articles Section Rules for the installation of electrical installations (PUE).

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