Support grounding resistance 10 kv. Why is VLI re-grounding necessary? This document is in

GROUNDING OF OVERHEAD POWER LINES

To improve the reliability of power transmission lines, to protect electrical equipment from atmospheric and internal surges, as well as to ensure the safety of maintenance personnel, power transmission line supports must be grounded.

The resistance value of grounding devices is standardized by the "Rules for electrical installations".

On overhead power lines for a voltage of 0.4 kV with reinforced concrete poles in networks with isolated neutral, both the armature of the poles and the hooks and pins of the phase wires must be grounded. The resistance of the grounding device must not exceed 50 ohms.

In networks with a grounded neutral, hooks and pins of phase wires installed on reinforced concrete supports, as well as the fittings of these supports, must be connected to a neutral grounded wire. Grounding and neutral conductors in all cases must have a diameter of at least 6 mm.

On overhead power lines for a voltage of 6-10 kV, all metal and reinforced concrete supports, as well as wooden poles on which lightning protection devices, power or instrument transformers, disconnectors, fuses or other devices are installed.

The resistances of the grounding devices of the supports are accepted for populated areas not higher than those given in Table. 18, and in uninhabited areas in soils with soil resistivity up to 100 Ohm m - no more than 30 Ohm, and in soils with a resistance above 100 Ohm m - no more than 0.3. When using insulators ShF 10-G, ShF 20-V and ShS 10-G on power lines for a voltage of 6-10 kV, the grounding resistance of supports in an uninhabited area is not standardized.

Table 18

Resistance of grounding devices of transmission towers

for voltage 6-10 kV

#G0Soil resistivity , Ohm m	Grounding device resistance, Ohm
Up to 100	To 10
100-500	" 15
500-1000	" 20
1000-5000	" 30
Over 5000	6 10

When making grounding devices, i.e. when electrically connecting grounded parts to the ground, they strive to ensure that the resistance of the grounding device is minimal and, of course, not higher than the values ​​\u200b\u200brequired #M12293 0 1200003114 3645986701 3867774713 77 4092901925 584910322 1540216064 77 77 PUE#S. A large proportion of the grounding resistance falls on the transition from the ground electrode to the ground. Therefore, in general, the resistance of the grounding device depends on the quality and condition of the soil itself, the depth of the ground electrodes, their type, quantity and relative position.

Grounding devices consist of grounding switches and grounding slopes connecting the grounding switches with grounding elements. As grounding slopes of reinforced concrete supports of power transmission lines for a voltage of 6-10 kV, all elements of the stressed reinforcement of the racks that are connected to the ground electrode should be used. If the supports are installed on guy wires, then guy wires of reinforced concrete supports should also be used as grounding conductors in addition to the reinforcement. Grounding slopes specially laid along the support must have a cross section of at least 35 mm or a diameter of at least 10 mm.

On overhead power lines with wooden poles, it is recommended to use bolted connection of grounding slopes; on metal and reinforced concrete supports, the connection of grounding slopes can be made both welded and bolted.

Grounding conductors are metal conductors laid in the ground. Grounding switches can be made in the form of vertically hammered rods, pipes or angles, interconnected by horizontal conductors made of round or flat steel in the grounding center. The length of vertical grounding conductors is usually 2.5-3 m. Horizontal grounding conductors and the top of vertical grounding conductors must be at least 0.5 m deep, and at arable land- at a depth of 1 m. Grounding conductors are interconnected by welding.

When installing supports on piles, a metal pile can be used as a ground electrode, to which the ground outlet of reinforced concrete supports is connected by welding.

To reduce the area of ​​land occupied by the earth electrode, deep earth electrodes are used in the form of rods made of round steel, immersed vertically into the ground by 10-20 m or more. On the contrary, in dense or stony soils, where it is impossible to bury vertical earth electrodes, surface horizontal earth electrodes are used, which are several beams of strip or round steel laid in the ground at a shallow depth and connected to a grounding descent.

All types of grounding significantly reduce the magnitude of atmospheric and internal overvoltages on power lines. However, still these protective earthing in some cases, it is not enough to protect the insulation of power lines and electrical appliances from surges. Therefore, additional devices are installed on the lines, which primarily include protective spark gaps, tubular and valve arresters.

The protective property of the spark gap is based on the creation of a "weak" spot in the line. Isolation of the spark gap, i.e. the air distance between its electrodes is such that its electrical strength is sufficient to withstand the operating voltage of the power transmission line and prevent the operating current from shorting to the ground, and at the same time it is weaker than the line insulation. When lightning strikes the wires of a power transmission line, a lightning discharge breaks through a "weak" place (spark gap) and passes into the ground without violating the line insulation. Protective spark gaps 1 (Fig. 22, a, b) consist of two metal electrodes 2 installed at a certain distance from each other. One electrode is connected to the wire 6 of the power transmission line and is isolated from the support by an insulator 5, and the other is grounded (4). An additional protective gap 3 is connected to the second electrode. On lines for a voltage of 6-10 kV with pin insulators, the shape of the electrodes is made in the form of horns, which ensures the stretching of the arc during discharge. In addition, on this power line, protective gaps are arranged directly on the ground slope laid along the support (Fig. 23).

Rice. 22. Protective spark gap for power lines for voltage up to 10 kV:

a - electrical circuit; b - installation scheme

Rice. 23. The device of the protective gap on the support

Tubular and valve arresters are installed, as a rule, at the approaches to substations, power transmission line crossings through communication lines and power lines, electrified railways, as well as to protect cable inserts on power lines. Spark gaps are devices with spark gaps and devices for extinguishing the arc. They are installed in the same way as the protective gaps - parallel to the protected insulation.

Valve arresters of type РВ are designed for protection against atmospheric overvoltages of insulation of electrical equipment. They are produced for a voltage of 3.6 and 10 kV and can be installed both outdoors - on power lines, and indoors. The main electrical characteristics of the arresters are given in Table. 19. The design, overall, mounting and connecting dimensions of the arresters are shown in fig. 24.

Table 19

Characteristics of valve arresters

#G0 Indicators	RVO-0.5	RVO-3	RVO-6	RVO-10
Rated voltage, kV
Breakdown voltage at a frequency of 50 Hz in a dry state and in the rain, kV:
at least
no more				30,5
Creepage distance length of external insulation (not less than), cm
Weight, kg

Fig. 24 RVO-type valve arrester:

1 - M8x20 bolt; 2 - tire; 3 - spark gap; 4 - two bolts M10x25 for fastening

arrester; 5 - resistor; 6 - clamp; 7 - M8x20 bolt for connecting the ground wire

The arrester consists of a multiple spark gap 3 and a resistor 5, which are enclosed in a hermetically sealed porcelain cover 2. The porcelain cover is designed to protect the internal elements of the arrester from exposure to external environment and ensuring the stability of the characteristics. The resistor consists of vilite disks made of silicon carbide, has a non-linear current-voltage characteristic, i.e. its resistance decreases under the influence of high voltage, and vice versa.

The multiple spark gap consists of several single gaps, which are formed by two shaped brass electrodes separated by an insulating gasket.

When an overvoltage dangerous for the insulation of the equipment appears, a breakdown of the spark gap occurs, and the resistor is under high voltage. The resistance of the resistor decreases sharply and the lightning current passes through it without creating a voltage increase that is dangerous for the insulation. Following the breakdown of the spark gap, the accompanying power frequency current is interrupted at the first voltage transition through zero.

The letter marking of arresters means the type and design of the arrester, and the numbers indicate the rated voltage.

Tubular spark gaps (Fig. 25) are an insulating tube 1 with an internal spark gap, which is formed by two metal electrodes 2 and 3. The tube is made from a gas-generating material and one of its sides is tightly closed. When lightning strikes, a spark gap breaks through and an arc occurs between the electrodes. Under the action of a high arc temperature, gases are rapidly released from the insulating tube and the pressure in it rises. Under the influence of this pressure, gases exit through the open end of the tube, which creates a longitudinal blast, which stretches and cools the arc. When the accompanying current passes through the zero position, the stretched and cooled arc goes out and the current breaks. To protect the surface of the insulating tube from destruction by leakage currents, an external spark gap is arranged in the tubular spark gap.

Figure 25. Tubular arrester

Tubular arresters are made of fiber-bakelite type RTF or vinyl plastic type RTV. Characteristics of tubular arresters are given in table. twenty.

Table 20

Characteristics of tubular arresters

#G0 Arrester type

Rated voltage, kV

Length of external spark gap, mm

VLI re-grounding is the grounding of the PEN conductor from the complex transformer substation 10 kV/0.4 kV. Its main purpose is to improve the safety of power transmission lines. VLI stands for overhead power line with insulated SIP wiring. Overhead lines (overhead lines) are laid from a transformer station with a dead-earthed neutral, on supports made of wood or reinforced concrete.

Types of supports

Wooden

A similar design is made from logs without bark (roundwood). The length of one log is from 5 to 13 meters in increments of 50 cm. The thickness of the support is from 12 to 26 centimeters in increments of 20 mm. In order for the wooden support to rot more slowly, it is covered with a special antiseptic. There are two types of this design: C1 and C2.

Reinforced concrete

Such a device is made of concrete and reinforcement in the form of a rectangle or in the form of a trapezoid. The reinforced concrete device has its own marking and is marked as SV. After these letters, numbers are written that indicate the length of the structure. For example, backwater CB 85. The figure indicates that its length is 8.5 meters. The photo below clearly shows what the reinforced concrete support looks like:

The following reinforced concrete structures are used:

• CB 105;
• CB 110;
• CB 95;
• CB 85.

In order to carry out secondary grounding of the PEN conductor, fittings are welded on both sides of the device.

What is it for?

What is VLI re-grounding and why is it called that? The fact is that the wire cable is already grounded to a complex transformer substation. (transformer substation with a dead-earthed neutral) is 2 or 4, which are carried out along the VLI. One of the cable conductors is considered the main - PEN conductor, the rest - phase. In turn, the PEN conductor is divided into N (zero working) and PE (zero protective). This is the case if it is on a backwater and there is an input device (VU) on the device or in a shield in the room.

The schema looks like this:

The PUE states that re-grounding the VLI means immersing the PEN or PE conductor in the ground in the air electrical line with insulated wires.

Important! The repeated grounding circuit is carried out on a backwater without an introductory device or an introductory shield (VShch). It is connected to an introductory machine or to a joint knife switch.

The protective and working neutral wires are connected at the top of the reinforced concrete pillar (reinforced concrete column) to the reinforcing outlet. If there is a strut pole, then it is necessary to attach it to it, and not just to the main one.

The photo below shows how to build a re-grounding of the VLI of the main conductor using on a pass-through pole, without a tap. It is necessary to carry out this on every third support of the overhead line and on a pole that leads to a residential building.

A grounding descent is installed on a wooden support (indicated by the number 3 in the diagram below). As a rule, it is produced from a metal wire. All this is attached to a pin electrode, which is driven into the ground. If the wire is more than 6 mm, then it is desirable that it be made of galvanized metal, and if it is less than 6 mm, it should be made of ferrous metal with an anti-corrosion agent applied.

• 1 - place of welding;
• 2 - ground electrodes;
• 3 - descent.

In a similar way, VLI is re-grounded for a reinforced concrete pole only without a reinforcing outlet.

According to the rules for the installation of electrical installations, if on wooden structure If the PEN conductors were re-grounded, then it is necessary to ground all the pins and hooks of the metal support completely. If, however, a repeated ground loop is not organized on a pillar made of wood or reinforced concrete, then nothing needs to be done (PUE 2.4.41).

Electrical equipment made of metal, which is located on supports, in without fail must be grounded by individual wires. These are equipment such as VU shields, lightning protection or high voltage protection. In the case of a transformer substation with a solidly grounded neutral, the resistance of the secondary ground electrode must be 30 ohms or less.

Please note! For private housing, re-protection of VLI PEN conductors does not exempt from installing a special ground loop. About that, we talked in the corresponding article!

If it is necessary to re-ground the VLI from the transformer substation to the living quarters at a distance of 800 m, it should be done in the following places:

• on overhead line poles, which are located near the transformer substation and near the house;
• on anchor posts overhead lines;
• on a support with a distance of 100 meters from the main support, which has grounding.

Useful

Title page
List of drawings
Explanatory note
Wooden poles VL 0.4 kV. Hook grounding and swivel neutral wire grounding
Wooden poles VL 35 kV. Rope grounding on intermediate and anchor supports
Wooden supports VL 6 - 10 kV. The device of protective gaps on supports at the intersection with overhead lines or communication lines
Wooden supports VL 20 kV. The device of protective gaps on supports at the intersection with overhead lines or communication lines
Wooden poles VL 35 kV. The device of protective gaps on supports at the intersection with overhead lines or communication lines
Wooden supports VL 6 - 10 kV. Grounding of tubular arresters RT-6 and RT-10 on anchor and intermediate supports
Wooden supports VL 6 - 10 kV. Grounding of tubular arresters RT-6 and RT-10 (transitional) on an anchor elevated support
Wooden supports VL 6 - 10 kV. Grounding of the cable box and tubular surge arresters on the end support
Wooden supports VL 20 kV (transitional). Grounding of tubular arresters RT-20 on an intermediate elevated support
Wooden supports VL 20 kV (transitional). Grounding of tubular arresters RT-20 on an anchor elevated support
Wooden poles VL 35 kV. Grounding of tubular arresters RT-35 on an anchor support
Reinforced concrete supports VL 0.4 kV. Grounding of intermediate OP-0.4 and intermediate cross PK-0.4 supports
Reinforced concrete supports VL 0.4 kV. Grounding of the intermediate transitional support PP-0.4
Reinforced concrete supports VL 0.4 kV. Grounding of angle anchor supports UA-I-0.4 and UA-II-0.4
Reinforced concrete supports VL 0.4 kV. Grounding of terminal K-0.4 and anchor A-0.4 supports
Reinforced concrete supports VL 0.4 kV. Grounding of branch anchor support OA-0.4
Reinforced concrete supports VL 0.4 kV. Grounding of the branch transitional support OP-0.4
Reinforced concrete supports VL 0.4 kV. Grounding of input boxes on intermediate and end supports for connecting electric motors of mobile machines
Reinforced concrete supports VL 0.4 kV. Grounding the box with AP50-T for sectioning the main on the anchor support
Reinforced concrete supports VL 0.4 kV. Grounding of the cable box 4 km, arresters RVN-0.5, lamp SPO-200 on the end support
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of intermediate supports for uninhabited and populated areas P10-1B; P20-1B; P10-2B; P20-2B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of angular intermediate supports for uninhabited and populated areas UP10-1B; UP20-1B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of end supports for uninhabited and populated areas K10-1B; K10-2B; K20-1B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of branch intermediate supports for uninhabited areas OP10-1B; OP20-1B; OP10-2B; OP20-2B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of branch supports for uninhabited areas OP10-1B; OP10-2B and 020-1B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of branch angular intermediate supports for uninhabited areas OUP10-1B; OUP20-1B
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of the KMA(KMCH) cable box and arresters RT-6; RT-10 on end support
Reinforced concrete supports VL 6 - 10 and 20 kV. Grounding of terminal supports of overhead lines 6 - 10 and 20 kV with disconnectors for populated and uninhabited areas KR10-1B; KR10-2B; KR10-3B; KR20-1B
Reinforced concrete supports of 35 kV overhead lines. Grounding of intermediate supports for uninhabited and populated areas P35-1B and P35-2B
Reinforced concrete supports of 35 kV overhead lines. Grounding of intermediate supports with a cable for uninhabited and populated areas PT35-1B and PT35-2B
Reinforced concrete supports of 35 kV overhead lines. Grounding of corner anchor supports for uninhabited and populated areas UA35-16; UA35-26
Reinforced concrete supports of 35 kV overhead lines. Grounding of an angular intermediate support for an uninhabited area UP35-1B
Reinforced concrete supports of 35 kV overhead lines. Grounding of end and anchor supports for uninhabited and populated areas K35-1B; K35-2B; A35-1B; A35-2B
Reinforced concrete supports of 35 kV overhead lines. Grounding of angular intermediate, end and anchor supports with a cable for uninhabited and populated areas UPT35-1B; KT35-1B; KT35-2B; AT35-1B; AT35-2B
Reinforced concrete supports of 35 kV overhead lines. Grounding of corner anchor supports with a cable for uninhabited and populated areas UAT35-1B; UAT35-2B
Reinforced concrete supports VL 10; twenty; 35 kV. Grounding of transitional intermediate support PP35-B; PP20-B; PP10-B
Reinforced concrete supports of 35 kV overhead lines. Grounding of an intermediate transitional support with a cable PPT35-B
Reinforced concrete supports VL 10; twenty; 35 kV. Grounding of the angular anchor transitional support UAP35-B; UAP20-B; UAP10-B
Reinforced concrete supports of 135 kV overhead lines. Grounding of the UAPT35-B corner anchor transitional support
Reinforced concrete supports VL 10; twenty; 35 kV. Grounding of the terminal transitional support KP35-B; KP20-B; KP10-B
Reinforced concrete supports of 35 kV overhead lines. Grounding of the end transitional support with cable KPT35-B
Disconnecting point 20 kV with an automatic sectional separator on a reinforced concrete support. grounding
Examples of re-grounding the neutral wire, hooks and pins on reinforced concrete and wooden supports
Sketches of earth electrodes for R =<10 ом
Sketches of earth electrodes for R =<15 ом; R = < 20 ом
Sketches of earth electrodes for R =< 30 ом
Formulas for determining the resistance to current spreading of various ground electrodes
Initial data for the calculation of ground electrodes
Reinforced concrete and wooden supports. Grounding supports. Choice of clamps
Wooden poles VL 0.4 kV. Grounding hooks and rotary grounding of the neutral wire. Nodes. Details
Knots and details
Examples of grounding devices. Knots

DEVELOPED taking into account the requirements of state standards, building codes and regulations, recommendations of scientific and technical councils for reviewing draft chapters. The draft chapters were reviewed by the working groups of the Coordinating Council for the revision of the EMP

PREPARED BY JSC "ROSEP", co-executor - JSC "Firma ORGRES"

AGREED in the prescribed manner with the Gosstroy of Russia, Gosgortekhnadzor of Russia, RAO "UES of Russia" (JSC "VNIIE") and submitted for approval by the Gosenergonadzor of the Ministry of Energy of Russia

From October 1, 2003, Chapter 2.4 of the "Electrical Installation Rules" of the sixth edition becomes invalid

The requirements of the Electrical Installation Rules are mandatory for all organizations, regardless of ownership and organizational and legal forms, as well as for individuals engaged in entrepreneurial activities without forming a legal entity.

Application area. Definitions

2.4.1. This chapter of the Rules applies to AC overhead power lines with voltage up to 1 kV, performed using insulated or bare wires.

Additional requirements for overhead lines up to 1 kV are given in Ch. 2.5, 6.3 and 7.7.

Cable inserts in the line and cable branches from the line must be carried out in accordance with the requirements of Ch. 2.3.

2.4.2. Overhead line (VL) of power transmission with voltage up to 1 kV - a device for the transmission and distribution of electricity through insulated or non-insulated wires located in the open air and attached by linear fittings to supports, insulators or brackets, to building walls and to engineering structures.

An overhead power line with a voltage of up to 1 kV using self-supporting insulated wires (SIP) is designated VLI.

Self-supporting insulated wire - insulated conductors twisted into a bundle, and the carrier conductor can be either insulated or uninsulated. The mechanical load can be taken either by the carrier conductor or by all conductors of the bundle.

2.4.3. Highway VL - a section of the line from the supply transformer substation to the end support.

Linear branches or branches to the input can be connected to the overhead line.

Linear branch from the overhead line - a section of the line connected to the main overhead line, having more than two spans.

A branch from the overhead line to the input is the section from the support of the main line or linear branch to the clamp (input insulator).

A branch from the VLI is allowed to be performed in the span.

2.4.4. The state of the overhead line in the calculations of the mechanical part:

• normal mode - mode with unbroken wires;
• emergency mode - mode with broken wires;
• installation mode - mode in the conditions of installation of supports and wires.

Mechanical calculation of overhead lines up to 1 kV in emergency mode is not performed.

General requirements

2.4.5. The mechanical calculation of the elements of the overhead line should be carried out according to the methods described in Ch. 2.5.

2.4.6. Overhead power lines should be placed so that the supports do not block the entrances to buildings and entrances to courtyards and do not impede the movement of vehicles and pedestrians. In places where there is a danger of collision with vehicles (at the entrances to yards, near exits from roads, at the intersection of roads), the supports must be protected from collision (for example, by bollards).

2.4.7. On the overhead line supports at a height of at least 2 m from the ground after 250 m on the overhead line, the following should be installed (applied): the serial number of the support; posters showing the distances from the overhead line pole to the cable communication line (on poles installed at a distance of less than 4 m to the communication cables), the width of the security zone and the phone number of the overhead line owner.

2.4.8. When passing VLI through forests and green spaces, clearing is not required. At the same time, the distance from the wires to trees and bushes with the largest SIP sag and their largest deviation should be at least 0.3 m.

When passing overhead lines with uninsulated wires through forests and green spaces, cutting down the clearing is not necessary. At the same time, the distance from the wires with the largest sag or the largest deviation to trees and bushes should be at least 1 m.

The distance from insulated wires to green spaces should be at least 0.5 m.

2.4.9. The structures of the overhead line supports must be protected from corrosion, taking into account the requirements of 2.5.25, 2.5.26 and building codes and regulations.

2.4.10. Protection of overhead lines from electrical overloads should be carried out in accordance with the requirements of Ch. 3.1.

Climatic conditions

2.4.11. Climatic conditions for the calculation of overhead lines up to 1 kV in normal mode should be taken as for overhead lines up to 20 kV in accordance with 2.5.38 - 2.5.74. In this case, for overhead lines up to 1 kV, the following should be taken:

• when calculating according to 2.5.52: Cx= 1.1 - for SIP, free or covered with ice;
• when calculating according to 2.5.54 and 2.5.55:
• γnw = γng = 0.8 - for single-circuit overhead lines;
• γnw = γng = 0.9 - for single-circuit overhead lines with suspension on PV supports;
• γnw = 1.0 and γng = 1.2 - for double-circuit and multi-circuit overhead lines, as well as when hanging on the supports of overhead lines of a self-supporting non-metallic optical cable (OKSN);
• γp = 1.0 and K1 = 1.0 - in all cases.

2.4.12. The calculation of the span length of the branch from the overhead line to the input according to 2.4.20 must be carried out in icy conditions for two cases:

1. wind direction at an angle of 90º to the axis of the overhead line, the wires of the overhead line are covered with ice be, the thickness of the ice wall on the branch wires b0 = 0.5 be;
2. wind direction along the overhead line (angle 0º), ice wall thickness on branch wires b0 = be.

In this case, in both cases, one should take into account the reduction in the tension of the branch wires when the top of the support is deflected.

Wires. Linear reinforcement

2.4.13. On overhead lines, as a rule, self-supporting insulated wires (SIPs) should be used.

SIP should be classified as protected, have insulation made of slow-burning, light-stabilized synthetic material that is resistant to ultraviolet radiation and ozone.

2.4.14. According to the conditions of mechanical strength on the mains of the overhead line, on the linear branch from the overhead line and on the branches to the inputs, wires with the minimum sections indicated in tables 2.4.1 and 2.4.2 should be used.

Table 2.4.1 Minimum allowable sections of insulated wires

* In parentheses is the cross section of the core of self-supporting insulated wires twisted into a bundle, without a carrier wire.

Table 2.4.2 Minimum allowable sections of bare and insulated wires

2.4.15. When constructing overhead lines in places where operating experience has established the destruction of wires from corrosion (the coasts of the seas, salt lakes, industrial areas and areas of saline sands), as well as in places where, based on survey data, it is possible, self-supporting insulated wires with an insulated core should be used. .

2.4.16. The overhead line, as a rule, should be carried out with wires of a constant cross section.

2.4.17. Mechanical calculation of wires must be carried out according to the method of permissible stresses for the conditions specified in 2.5.38 - 2.5.74. In this case, the voltages in the wires should not exceed the allowable voltages given in Table. 2.4.3, and the distances from wires to the ground surface, intersected structures and grounded support elements must meet the requirements of this chapter.

The calculation uses the parameters of the wires given in Table. 2.5.8.

Table 2.4.3 Permissible mechanical stress in the wires of overhead lines up to 1 kV

2.4.18. All types of mechanical loads and impacts on SIP with a carrier core should be taken by this core, and on SIP without a carrier wire, all cores of a twisted bundle should be perceived.

2.4.19. The length of the span of the branch from the overhead line to the input should be determined by calculation depending on the strength of the support on which the branch is performed, the height of the suspension of the branch wires on the support and at the input, the number and cross section of the wires of the branch wires.

At distances from the overhead line to the building exceeding the calculated span of the branch, the required number of additional supports is installed.

2.4.20. The choice of the cross section of current-carrying conductors for long-term permissible current should be carried out taking into account the requirements of Ch. 1.3.

The cross section of current-carrying conductors must be checked according to the condition of heating during short circuits (SC) and for thermal stability.

2.4.21. Fastening, connection of the SIP and connection to the SIP should be done as follows:

1. fastening the wire of the VLI highway on intermediate and angular intermediate supports - using supporting clamps;
2. fastening the wire of the VLI main on anchor-type supports, as well as the end fastening of the branch wires on the VLI support and at the input - using tension clamps;
3. connection of the VLI wire in the span - using special connecting clamps; in the loops of anchor-type supports, it is allowed to connect an uninsulated carrier wire using a ram clamp. Connecting clamps designed to connect the carrier wire in the span must have a mechanical strength of at least 90% of the breaking force of the wire;
4. connection of the phase wires of the VLI highway - using connecting clamps having an insulating coating or a protective insulating sheath;
5. connection of wires in the span of the branch to the input is not allowed;
6. connection of grounding conductors - using flat clamps;
7. branch clamps should be used in the following cases:
   • branches from phase conductors, with the exception of SIP with all carrier conductors of the bundle;
   • branches from the carrier core.

2.4.22. Fastening of supporting and tension clamps to VLI supports, walls of buildings and structures should be carried out using hooks and brackets.

2.4.23. The design forces in the support and tension clamps, attachment points and brackets in normal mode should not exceed 40% of their mechanical breaking load.

2.4.24. Wire connections in spans of overhead lines should be made using connecting clamps that provide mechanical strength of at least 90% of the breaking force of the wire.

In one span of overhead lines, no more than one connection is allowed for each wire.

In the spans of the intersection of overhead lines with engineering structures, the connection of overhead lines is not allowed.

The connection of wires in the loops of the anchor supports should be made using clamps or welding.

Wires of different brands or sections should be connected only in the anchor support loops.

2.4.25. It is recommended to fasten uninsulated wires to insulators and insulating traverses on overhead line supports, with the exception of supports for crossings, as a single one.

Fastening of bare wires to pin insulators on intermediate supports should be carried out, as a rule, on the neck of the insulator on its inner side with respect to the support post.

2.4.26. Hooks and pins should be calculated in the normal mode of operation of the overhead line according to the method of breaking loads.

In this case, the forces shall not exceed the values ​​given in 2.5.101.

Arrangement of wires on poles

2.4.27. On supports, any arrangement of insulated and uninsulated wires of overhead lines is allowed, regardless of the area of ​​\u200b\u200bclimatic conditions. The neutral wire of overhead lines with bare wires, as a rule, should be located below the phase wires. Insulated outdoor lighting wires laid on VLI supports can be placed above or below the SIP, and also be twisted into a SIP bundle. Uninsulated and insulated outdoor lighting wires laid on overhead line supports should, as a rule, be located above the PEN (PE) conductor of the overhead line.

2.4.28. Devices mounted on supports for connecting electrical receivers must be placed at a height of at least 1.6 m from the ground.

Protective and sectioning devices installed on supports should be placed below the wires of the overhead line.

2.4.29. The distances between uninsulated wires on the support and in the span, according to the conditions of their convergence in the span with the largest sag up to 1.2 m, must be at least:

• with a vertical arrangement of wires and an arrangement of wires with a horizontal displacement of not more than 20 cm: 40 cm in I, II and III regions on ice, 60 cm in IV and special regions on ice;
• at other locations of wires in all areas on ice at wind speed on ice: up to 18 m / s - 40 cm, more than 18 m / s - 60 cm.

With the largest sag of more than 1.2 m, the indicated distances must be increased in proportion to the ratio of the largest sag to the sag of 1.2 m.

2.4.30. The vertical distance between insulated and non-insulated wires of overhead lines of different phases on a support at a branch from an overhead line and at the intersection of different overhead lines on a common support must be at least 10 cm.

The distance from the wires of the overhead line to any support elements must be at least 5 cm.

2.4.31. When jointly suspended on common supports of VLI and VL up to 1 kV, the vertical distance between them on the support and in the span at an ambient temperature of plus 15 ºС without wind should be at least 0.4 m.

2.4.32. When two or more VLIs are jointly suspended on common supports, the distance between the SIP bundles must be at least 0.3 m.

2.4.33. When jointly suspended on common supports of wires of overhead lines up to 1 kV and wires of overhead lines up to 20 kV, the vertical distance between the nearest wires of overhead lines of different voltages on a common support, as well as in the middle of the span at an ambient temperature of plus 15 ºС without wind, should be at least:

• 1.0 m - when hanging SIP with an insulated carrier and with all carrier wires;
• 1.75 m - when hanging SIP with an uninsulated carrier wire;
• 2.0 m - when hanging uninsulated and insulated wires of overhead lines up to 1 kV.

2.4.34. When hanging on common supports wires of overhead lines up to 1 kV and protected wires of overhead lines 6-20 kV (see 2.5.1), the vertical distance between the nearest wires of overhead lines up to 1 kV and overhead lines 6-20 kV on the support and in the span at a temperature of plus 15 ºС without wind should be at least 0.3 m for SIP and 1.5 m for uninsulated and insulated wires of overhead lines up to 1 kV.

Insulation

2.4.35. Self-supporting insulated wire is attached to the supports without the use of insulators.

2.4.36. On overhead lines with uninsulated and insulated wires, regardless of the material of the supports, the degree of atmospheric pollution and the intensity of lightning activity, insulators or traverses made of insulating materials should be used.

Selection and calculation of insulators and fittings are carried out in accordance with 2.5.100.

2.4.37. On the supports of branches from overhead lines with uninsulated and insulated wires, as a rule, multi-neck or additional insulators should be used.

Grounding. Surge protection

2.4.38. Grounding devices designed for re-grounding, protection against lightning surges, grounding of electrical equipment installed on overhead line supports must be made on the overhead line supports. The resistance of the grounding device must be no more than 30 ohms.

2.4.39. Metal supports, metal structures and reinforcement of reinforced concrete support elements must be connected to the PEN conductor.

2.4.40. On reinforced concrete poles, the PEN conductor should be connected to the reinforcement of reinforced concrete pillars and struts of the poles.

2.4.41. Hooks and pins of wooden poles of overhead lines, as well as metal and reinforced concrete poles when suspended on them with an insulated carrier conductor or with all carrier conductors of the bundle, are not subject to grounding, with the exception of hooks and pins on the poles, where repeated grounding and grounding are performed to protect against atmospheric overvoltages.

2.4.42. Hooks, pins and fittings of overhead lines with a voltage of up to 1 kV, limiting the crossing span, as well as supports on which joint suspension is carried out, must be grounded.

2.4.43. On wooden poles of the overhead line, when passing to the cable line, the grounding conductor must be connected to the PEN conductor of the overhead line and to the metal sheath of the cable.

2.4.44. Protective devices installed on overhead lines for protection against lightning surges must be connected to the grounding conductor with a separate descent.

2.4.45. The connection of the grounding conductors to each other, their connection to the upper grounding outlets of the racks of reinforced concrete supports, to hooks and brackets, as well as to grounded metal structures and to grounded electrical equipment installed on overhead line supports, must be carried out by welding or bolted connections.

The connection of grounding conductors (descents) to the grounding conductor in the ground must also be carried out by welding or have bolted connections.

2.4.46. In a populated area with one- and two-story buildings, overhead lines must have grounding devices designed to protect against atmospheric surges. The resistance of these grounding devices should be no more than 30 ohms, and the distances between them should be no more than 200 m for areas with up to 40 thunderstorm hours per year, 100 m for areas with more than 40 thunderstorm hours per year.

In addition, grounding devices must be made:

1. on supports with branches to the entrances to buildings in which a large number of people can be concentrated (schools, nurseries, hospitals) or which are of great material value (livestock and poultry premises, warehouses);
2. on the end supports of the lines having branches to the inputs, while the greatest distance from the adjacent grounding of the same lines should be no more than 100 m for areas with up to 40 and 50 m of thunderstorm hours per year - for areas with more than 40 thunderstorm hours per year .

2.4.47. At the beginning and end of each VLI line, it is recommended to install clamps on the wires for connecting voltage control devices and portable grounding.

Grounding lightning surge protection devices are recommended to be combined with the re-grounding of the PEN conductor.

2.4.48. Requirements for grounding devices for re-grounding and protective conductors are given in 1.7.102, 1.7.103, 1.7.126. As grounding conductors on overhead line supports, it is allowed to use round steel with an anti-corrosion coating with a diameter of at least 6 mm.

2.4.49. Guys of overhead lines must be connected to the ground conductor.

supports

2.4.50. Supports made of various materials can be used on overhead lines.

For overhead lines, the following types of supports should be used:

1. intermediate, installed on straight sections of the overhead line route. These supports in normal operating modes should not perceive the forces directed along the overhead line;
2. anchor, installed to limit the anchor span, as well as in places where the number, grades and cross sections of overhead lines change. These supports should perceive, in normal operating modes, the forces from the difference in the tension of the wires directed along the overhead line;
3. angular, installed in places where the direction of the overhead line route changes. These supports, under normal operating conditions, must perceive the resulting load from the tension of the wires of adjacent spans. Corner supports can be intermediate and anchor type;
4. terminal, installed at the beginning and end of the overhead line, as well as in places limiting cable inserts. They are anchor-type supports and must perceive, in normal operating modes of overhead lines, the one-sided tension of all wires.

Supports on which branches from overhead lines are carried out are called branch; supports on which the intersection of overhead lines of different directions or the intersection of overhead lines with engineering structures is carried out - cross. These supports can be of all the above types.

2.4.51. Support structures should provide the ability to install:

• street lighting fixtures of all types;
• end cable couplings;
• protective devices;
• sectioning and switching devices;
• cabinets and shields for connecting electrical receivers.

2.4.52. Supports, regardless of their type, can be free-standing, with braces or braces.

Support guys can be attached to anchors installed in the ground, or to stone, brick, reinforced concrete and metal elements of buildings and structures. The cross section of the guys is determined by calculation. They can be stranded or round steel. The cross section of single-wire steel braces must be at least 25 mm2.

2.4.53. The overhead line supports must be calculated according to the first and second limit state in the normal operation of the overhead line for climatic conditions according to 2.4.11 and 2.4.12.

Intermediate supports must be designed for the following combinations of loads:

• simultaneous action of transverse wind load on wires, free or covered with ice, and on the structure of the support, as well as the load from the tension of branch wires to inputs, free from ice or partially covered with ice (according to 2.4.12);
• on the load from the tension of the wires of the branches to the inputs covered with ice, while it is allowed to take into account the deviation of the support under the action of the load;
• on a conditional design load equal to 1.5 kN, applied to the top of the support and directed along the axis of the overhead line.

Corner supports (intermediate and anchor) must be designed for the resulting load from the tension of the wires and the wind load on the wires and the structure of the support.

Anchor supports must be designed for the difference in tension of the wires of adjacent spans and the transverse load from wind pressure with and without ice on the wires and the support structure. For the smallest value of the tension difference, 50% of the largest value of the unilateral tension of all wires should be taken.

End supports must be designed for one-sided tension of all wires.

Branch supports are calculated for the resulting load from the tension of all wires.

2.4.54. When installing supports on flooded sections of the route, where soil erosion or ice drift is possible, the supports must be strengthened (earth filling, paving, banquettes, installation of ice cutters).

Dimensions, intersections and convergence

2.4.55. The vertical distance from the VLI wires to the ground surface in populated and uninhabited areas to the ground and the carriageway of the streets must be at least 5 m. It can be reduced in hard-to-reach areas up to 2.5 m and inaccessible (mountain slopes, rocks, cliffs) - up to 1 m.

When crossing the impassable part of the streets with branches from the VLI to the inputs to the buildings, the distance from the SIP to the sidewalks of the footpaths can be reduced to 3.5 m.

The distance from the SIP and insulated wires to the ground on the branches to the input must be at least 2.5 m.

The distance from bare wires to the ground surface on the branches to the inputs must be at least 2.75 m.

2.4.56. The distance from the wires of the overhead line in populated and uninhabited areas with the largest sag of the wires to the ground and the carriageway of the streets must be at least 6 m. The distance from the wires to the ground can be reduced in hard-to-reach areas to 3.5 m and in inaccessible areas (mountain slopes , rocks, cliffs) - up to 1 m.

2.4.57. The horizontal distance from the SIP at their greatest deviation to the elements of buildings and structures should be at least:

• 1.0 m - to balconies, terraces and windows;
• 0.2 m - to the blank walls of buildings, structures.

It is allowed to pass VLI and VL with insulated wires over the roofs of buildings and structures (except for those specified in Chapters 7.3 and 7.4), while the vertical distance from them to the wires must be at least 2.5 m.

2.4.58. The horizontal distance from the wires of the overhead line with their greatest deviation to buildings and structures should be at least:

• 1.5 m - to balconies, terraces and windows;
• 1.0 m - to blank walls.

The passage of overhead lines with bare wires over buildings and structures is not allowed.

2.4.59. The smallest distance from SIP and overhead lines to the surface of the earth or water, as well as to various structures when passing overhead lines over them, is determined at the highest air temperature without taking into account the heating of overhead lines by electric current.

2.4.60. When laying along the walls of buildings and structures, the minimum distance from the SIP should be:

• with horizontal laying
• above the window, front door - 0.3 m;
• under the balcony, window, cornice - 0.5 m;
• to the ground - 2.5 m;
• with vertical laying
• to the window - 0.5 m;
• to the balcony, front door - 1.0 m.

The clear distance between the SIP and the wall of the building or structure must be at least 0.06 m.

2.4.61. Horizontal distances from the underground parts of supports or earthing supports to underground cables, pipelines and ground columns for various purposes must be at least those given in Table 2.4.4.

Table 2.4.4 The smallest allowable horizontal distance from the underground parts of supports or grounding devices of supports to underground cables, pipelines and ground columns

2.4.62. When crossing overhead lines with various structures, as well as with streets and squares of settlements, the intersection angle is not standardized.

2.4.63. Crossing overhead lines with navigable rivers and canals is not recommended. If it is necessary to perform such an intersection, overhead lines must be constructed in accordance with the requirements of 2.5.268 - 2.5.272. When crossing non-navigable rivers and canals, the shortest distances from the overhead line wires to the highest water level should be at least 2 m, and to the ice level - at least 6 m.

2.4.64. The intersection and convergence of overhead lines with voltage up to 1 kV with overhead lines with voltage above 1 kV, as well as the joint suspension of their wires on common supports, must be carried out in compliance with the requirements given in 2.5.220 - 2.5.230.

2.4.65. It is recommended to cross overhead lines (VLI) up to 1 kV on cross supports; their intersection in the span is also allowed. The vertical distance between the wires of intersecting overhead lines (VLI) must be at least: 0.1 m on the support, 1 m in the span.

2.4.66. At the intersection of overhead lines up to 1 kV, intermediate supports and anchor-type supports can be used with each other.

When crossing overhead lines up to 1 kV between themselves in the span, the intersection should be chosen as close as possible to the support of the upper crossing overhead line, while the horizontal distance from the supports of the crossing overhead line to the wires of the crossed overhead line with their greatest deviation should be at least 2 m.

2.4.67. With parallel passage and approach of overhead lines up to 1 kV and overhead lines above 1 kV, the horizontal distance between them must be at least those specified in 2.5.230.

2.4.68. Joint suspension of wires of overhead lines up to 1 kV and uninsulated wires of overhead lines up to 20 kV on common supports is allowed subject to the following conditions:

1. wires of overhead lines up to 20 kV should be located above the wires of overhead lines up to 1 kV;
2. wires of overhead lines up to 20 kV, fixed on pin insulators, must have a double fastening.

2.4.69. When hanging on common supports wires of overhead lines up to 1 kV and protected wires of 6-20 kV overhead lines, the following requirements must be observed:

1. VL up to 1 kV must be carried out according to the design climatic conditions VL up to 20 kV;
2. wires of VLZ 6-20 kV should be located, as a rule, above the wires of overhead lines up to 1 kV;
3. fastening of wires of VLZ 6-20 kV on pin insulators must be reinforced.

2.4.70. When crossing an overhead line (VLI) with an overhead line with a voltage above 1 kV, the distance from the wires of the crossing overhead line to the crossed overhead line (VLI) must comply with the requirements given in 2.5.221 and 2.5.227.

The cross section of the wires of the crossed overhead line should be taken in accordance with 2.5.223.

Intersections, convergence, joint suspension of overhead lines with communication lines, wire broadcasting and RK

2.4.71. The angle of intersection of the overhead line with the LAN * and LPV should be as close as possible to 90º. For cramped conditions, the intersection angle is not standardized.

According to their purpose, overhead communication lines are divided into long-distance telephone lines (MTS), rural telephone lines (STS), city telephone lines (GTS), wire broadcasting lines (LPV).

In terms of importance, overhead communication lines and wire broadcasting are divided into classes:

• MTS and STS lines: MTS main lines connecting Moscow with republican, regional and regional centers and the latter among themselves, and lines of the Ministry of Railways, passing along railways and across the territory of railway stations (class I); intrazonal MTS lines connecting republican, krai and regional centers with regional centers and the latter among themselves, and STS connecting lines (class II); STS subscriber lines (class III);
• GTS lines are not divided into classes;
• wire broadcasting lines: feeder lines with a rated voltage above 360 ​​V (class I); feeder lines with rated voltage up to 360 V and subscriber lines with voltage 15 and 30 V (class II).

* LAN should be understood as communication lines of the Ministry of Communications of the Russian Federation and other departments, as well as signaling lines of the Ministry of Railways.

LPV should be understood as wire broadcasting lines.

2.4.72. The vertical distance from the wires of the overhead line to the wires or overhead cables of the LAN and LPV in the crossing span with the largest sag of the wire of the overhead line should be:

• from SIP and insulated wires - at least 1 m;
• from bare wires - at least 1.25 m.

2.4.73. The vertical distance from the wires of the overhead line up to 1 kV to the wires or overhead cables of the LS or LPV when crossing on a common support should be:

• between SIP and drugs or LPV - not less than 0.5 m;
• between the uninsulated wire of the overhead line and the LPV - at least 1.5 m.

2.4.74. The intersection of the wires of the overhead line with wires or overhead cables of the LS and LPV in the span should be as close as possible to the overhead line support, but not less than 2 m from it.

2.4.75. The intersection of overhead lines with LS and LPV can be performed according to one of the following options:

1. wires of overhead lines and insulated wires of LS and LPV;
2. wires of overhead lines and underground or overhead cable LS and LPV;
3. VL wires and uninsulated wires LS and LPV;
4. underground cable insert in overhead lines with insulated and uninsulated wires LS and LPV.

2.4.76. When crossing overhead lines with insulated wires LS and LPV, the following requirements must be observed:

1. the intersection of uninsulated overhead lines with LAN wires, as well as with LPV wires with a voltage above 360 ​​V, should be carried out only in the span. The intersection of uninsulated wires of overhead lines with wires of LPV with a voltage of up to 360 V can be performed both in the span and on a common support;
2. poles of overhead lines that limit the span of intersection with LS of trunk and intrazonal communication networks and connecting lines of STS, as well as LPV with voltage above 360 ​​V, must be of the anchor type. At the intersection of all other LS and LPV, intermediate-type overhead lines are allowed, reinforced with an additional prefix or strut;
3. VL wires should be located above the LS and LPV wires. On the supports that limit the crossing span, uninsulated and insulated wires of overhead lines must be double fastened, the self-supporting insulated wire is fixed with anchor clamps. Wires LS and LPV on the supports that limit the span of the crossing must have a double fastening. In cities and urban-type settlements, newly built HP and LPV are allowed to be placed above the wires of overhead lines with a voltage of up to 1 kV.

2.4.77. When crossing overhead lines with an underground or overhead cable LS and LPV, the following requirements must be met:

1. the distance from the underground part of a metal or reinforced concrete pole and the earthing of a wooden pole to the underground cable of the LS and LPV in a populated area should, as a rule, be at least 3 m. and LPV); at the same time, the cable must be laid in a steel pipe or covered with a channel or angle steel along the length on both sides of the support at least 3 m;
2. in an uninhabited area, the distance from the underground part or ground electrode of the overhead line support to the underground cable of the LS and LPV must be at least the values ​​\u200b\u200bgiven in Table. 2.4.5;
3. wires of overhead lines should, as a rule, be located above the overhead cable of the LS and LPV (see also 2.4.76, clause 4);
4. connection of wires of overhead lines in the span of intersection with the overhead cable of the LS and LPV is not allowed. The cross section of the SIP carrier core must be at least 35 mm2. VL wires must be multi-wire with a cross section of at least: aluminum - 35 mm2, steel-aluminum - 25 mm2; cross-section of the SIP core with all the carrier conductors of the bundle - at least 25 mm2;
5. the metal sheath of the overhead cable and the rope on which the cable is suspended must be grounded on supports that limit the crossing span;
6. the horizontal distance from the base of the cable support of the LS and LPV to the projection of the nearest wire of the overhead line on the horizontal plane must be at least the maximum height of the support of the crossing span.

Table 2.4.5 The shortest distance from the underground part and the ground electrode of the overhead line support to the underground cable of the LS and LPV in an uninhabited area

2.4.78. When crossing VLI with uninsulated wires LS and LPV, the following requirements must be observed:

1. the intersection of the VLI with the LS and LPV can be performed in the span and on the support;
2. VLI supports, limiting the span of intersection with the LS of the main and intrazonal communication networks and with the connecting lines of the STS, must be of the anchor type. When crossing all other LS and LPV on VLI, it is allowed to use intermediate supports reinforced with an additional prefix or strut;
3. the carrier core of the self-supporting insulated wire or bundle with all carrier conductors at the intersection must have a tensile strength factor at the highest design loads of at least 2.5;
4. VLI wires should be located above the LS and LPV wires. On the supports that limit the crossing span, the supporting wires of the self-supporting insulated wire must be fixed with tension clamps. VLI wires are allowed to be placed under the LPV wires. At the same time, the LPV wires on the supports that limit the crossing span must have a double fastening;
5. the connection of the carrier core and the carrier conductors of the SIP bundle, as well as the LS and LPV wires in the crossing spans is not allowed.

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

1. the intersection of the wires of the overhead line with the wires of the LAN, as well as the wires of the LPV with a voltage above 360 ​​V, should be carried out only in the span.
   The intersection of wires of overhead lines with subscriber and feeder lines of LPV with a voltage of up to 360 V is allowed to be carried out on overhead line supports;
2. VL supports limiting the crossing span must be of the anchor type;
3. LS wires, both steel and non-ferrous, must have a tensile strength factor at the highest design loads of at least 2.2;
4. VL wires should be located above the LS and LPV wires. On the supports that limit the crossing span, the wires of the overhead line must have a double fastening. Wires of overhead lines with a voltage of 380/220 V and below are allowed to be placed under the wires of the LPV and GTS lines. At the same time, the wires of the LPV and the GTS lines on the supports that limit the crossing span must have a double fastening;
5. connection of wires of overhead lines, as well as wires of LS and LPV in crossing spans is not allowed. VL wires must be multi-wire with sections not less than: aluminum - 35 mm2, steel-aluminum - 25 mm2.

2.4.80. When crossing an underground cable insert in an overhead line with uninsulated and insulated wires LS and LPV, the following requirements must be observed:

1. the distance from the underground cable insert in the overhead line to the LS and LPV support and its ground electrode must be at least 1 m, and when laying the cable in an insulating pipe - at least 0.5 m;
2. the horizontal distance from the base of the overhead line cable support to the projection of the nearest LS and LPV wire on a horizontal plane must be at least the maximum height of the crossing span support.

2.4.81. The horizontal distance between the VLI wires and the LS and LPV wires during parallel passage or approach must be at least 1 m.

When approaching overhead lines with air LS and LPV, the horizontal distance between the insulated and uninsulated wires of the overhead line and the wires of the LS and LPV must be at least 2 m. In cramped conditions, this distance can be reduced to 1.5 m. In all other cases, the distance between the lines should be not less than the height of the highest support of the overhead line, LS and LPV.

When approaching overhead lines with underground or overhead cables LS and LPV, the distances between them should be taken in accordance with 2.4.77, paragraphs 1 and 5.

2.4.82. The proximity of overhead lines with antenna structures of transmitting radio centers, receiving radio centers, dedicated receiving points for wire broadcasting and local radio nodes is not standardized.

2.4.83. The wires from the overhead line support to the entrance to the building should not intersect with the branch wires from the LS and LPV, and they should be located at the same level or above the LS and LPV. The horizontal distance between the wires of the overhead line and the wires of the LS and LPV, television cables and descents from radio antennas at the inputs must be at least 0.5 m for SIP and 1.5 m for uninsulated wires of overhead lines.

2.4.84. Joint suspension of the overhead cable of rural telephone communication and VLI is allowed if the following requirements are met:

1. the zero core of the SIP must be insulated;
2. the distance from the SIP to the STS overhead cable in the span and on the VLI support must be at least 0.5 m;
3. each VLI support must have a grounding device, while the grounding resistance should be no more than 10 ohms;
4. on each VLI support, the PEN conductor must be re-grounded;
5. the carrying rope of the telephone cable, together with the metal mesh outer cover of the cable, must be connected to the grounding conductor of each support by a separate independent conductor (descent).

2.4.85. Joint suspension on common supports of uninsulated wires of overhead lines, LS and LPV is not allowed.

Joint suspension of uninsulated wires of overhead lines and insulated wires of LPV is allowed on common supports. In this case, the following conditions must be met:

1. the rated voltage of the overhead line should be no more than 380 V;
2. the distance from the lower LPV wires to the ground, between the LPV circuits and their wires must comply with the requirements of the current rules of the Ministry of Communications of Russia;
3. uninsulated wires of overhead lines should be located above the wires of the LPV; at the same time, the vertical distance from the lower wire of the overhead line to the upper wire of the LPV should be at least 1.5 m on the support, and at least 1.25 m in the span; when the LPV wires are located on the brackets, this distance is taken from the lower wire of the overhead line, located on the same side as the LPV wires.

2.4.86. Joint suspension of SIP VLI with uninsulated or insulated wires LS and LPV is allowed on common supports. In this case, the following conditions must be met:

1. the rated voltage of the VLI should be no more than 380 V;
2. rated voltage LPV should be no more than 360 V;
3. the rated voltage of the LAN, the calculated mechanical stress in the wires of the LAN, the distances from the lower wires of the LAN and LPV to the ground, between the circuits and their wires must comply with the requirements of the current rules of the Ministry of Communications of Russia;
4. VLI wires up to 1 kV should be located above the LS and LPV wires; at the same time, the vertical distance from the SIP to the upper wire of the LS and LPV, regardless of their relative position, must be at least 0.5 m on the support and in the span. Wires VLI and LS and LPV are recommended to be placed on different sides of the support.

2.4.87. Joint suspension on common supports of uninsulated wires of overhead lines and LAN cables is not allowed. Joint suspension on common supports of wires of overhead lines with a voltage of not more than 380 V and cables of LPV is allowed subject to the conditions specified in 2.4.85.

The optical fibers of the JCLN shall comply with the requirements of 2.5.192 and 2.5.193.

2.4.88. Joint suspension on common supports of wires of overhead lines with a voltage of not more than 380 V and telemechanics wires is allowed subject to the requirements given in 2.4.85 and 2.4.86, and also if telemechanics circuits are not used as wired telephone communication channels.

2.4.89. On the supports of VL (VLI) it is allowed to suspend fiber-optic communication cables (OK):

• non-metallic self-supporting (OKSN);
• non-metallic, wound on a phase wire or a bundle of self-supporting insulated wire (OKNN).

Mechanical calculations of VL (VLI) supports with OKSN and OKNN should be made for the initial conditions specified in 2.4.11 and 2.4.12.

The overhead line supports on which the OK is suspended, and their fixing in the ground, must be calculated taking into account the additional loads that arise in this case.

The distance from OKSN to the ground surface in populated and uninhabited areas should be at least 5 m.

The distances between the wires of overhead lines up to 1 kV and OKSN on the support and in the span must be at least 0.4 m.

Intersections and convergence of overhead lines with engineering structures

2.4.90. When crossing and parallel following overhead lines with railways and roads, the requirements set forth in Ch. 2.5.

Crossings can also be carried out using a cable insert in the overhead line.

2.4.91. When approaching overhead lines with highways, the distance from the wires of the overhead line to road signs and their supporting cables must be at least 1 m. The supporting cables must be grounded with a grounding device resistance of not more than 10 ohms.

2.4.92. When crossing and approaching overhead lines with contact wires and carrying cables of tram and trolleybus lines, the following requirements must be met:

1. Overhead lines should, as a rule, be located outside the area occupied by contact network structures, including supports.
   In this zone, the overhead line supports should be of the anchor type, and the uninsulated wires should be double fastened;
2. VL wires should be located above the carrier cables of the contact wires. The wires of the overhead line must be multi-wire with a cross section of at least: aluminum - 35 mm2, steel-aluminum - 25 mm2, the SIP carrier core - 35 mm2, the cross section of the SIP core with all the carrier conductors of the bundle - at least 25 mm2. Connection of wires of overhead lines in crossing spans is not allowed;
3. the distance from the wires of the overhead line with the largest sag must be at least 8 m to the head of the rail of the tram line and 10.5 m to the carriageway of the street in the area of ​​the trolleybus line.
4. In this case, in all cases, the distance from the wires of the overhead line to the carrier cable or contact wire must be at least 1.5 m;
5. crossing overhead lines with contact wires at the locations of the crossbars is prohibited;
6. joint suspension on the supports of trolleybus lines of contact wires and wires of overhead lines with a voltage of not more than 380 V is allowed subject to the following conditions: the supports of trolleybus lines must have mechanical strength sufficient for hanging wires of overhead lines, the distance between the wires of overhead lines and the bracket or the device for attaching the supporting cable of the contact wires must be at least 1.5 m.

2.4.93. When crossing and approaching overhead lines with cable cars and elevated metal pipelines, the following requirements must be met:

1. The overhead line must pass under the cable car; the passage of overhead lines over the cable car is not allowed;
2. cable cars must have walkways or nets below to protect overhead lines;
3. when passing overhead lines under a cable car or under a pipeline, the wires of the overhead lines must be at a distance from them: at least 1 m - with the smallest sag of the wires to the walkways or fencing nets of the cable car or to the pipeline; not less than 1 m - with the largest sag and the largest deviation of the wires to the elements of the cable car or to the pipeline;
4. when crossing an overhead line with a pipeline, the distance from the wires of the overhead line with their largest sag to the pipeline elements must be at least 1 m. The overhead line supports that limit the span of the intersection with the pipeline must be of the anchor type. The pipeline in the crossing span must be grounded, the resistance of the grounding conductor is not more than 10 Ohm;
5. when parallel following the overhead line with a cable car or pipeline, the horizontal distance from the wires of the overhead line to the cable car or pipeline must be at least the height of the support, and in cramped sections of the route with the greatest deviation of the wires - at least 1 m.

2.4.94. When approaching overhead lines with fire and explosion hazardous installations and airfields, the requirements given in 2.5.278, 2.5.291 and 2.5.292 should be followed.

2.4.95. The passage of overhead lines up to 1 kV with insulated and non-insulated wires is not allowed on the territories of sports facilities, schools (general education and boarding schools), technical schools, preschool institutions (nurseries, kindergartens, orphanages), orphanages, children's playgrounds, as well as on the territories of children's health camps.

In the above territories (except for sports and playgrounds), the passage of VLI is allowed, provided that the zero conductor of the SIP must be isolated, and its total conductivity must be at least the conductivity of the phase conductor of the SIP

In the modern world, lighting surrounds us everywhere: both at home and on the street. Moreover, the role of the outdoor type of lighting is very important in cities and villages, because it allows you to avoid many problems in the evening and at night.
When creating an outdoor type of lighting, one of the important stages of installation is the grounding of the poles.

In the course of grounding for outdoor lighting poles, it is necessary to understand and know the basic rules that are regulated by the relevant documentation (for example, PUE). This procedure is especially important for overhead lines (VL) and a network of outdoor lighting poles. We will talk about everything related to this procedure in this article.

What do you need

Outdoor lighting poles

Grounding for a network of outdoor lighting supports or overhead lines (0.4, 6-10, 20 and 35 kV) is of great importance, since it prevents the risk of electrical injury when in contact with structural elements in a situation where the cable insulation has been damaged. If there is grounding on a metal support of an outdoor type of lighting or overhead line, the voltage "spills" over the ground, thereby becoming safe for people. This indicator depends on the resistance of the soil in which the overhead line support is installed (0.4, 6-10, 20 and 35 kV). As a result, even if somewhere there was a violation of the insulation of the overhead line, the structures will remain safe.

Under normal operating conditions, pin insulators mounted on supports will provide reliable isolation of all wires from structural elements. But there are situations when the voltage in the network
significantly exceeds the voltage for which the overhead line was designed (0.4, 6-10, 20 and 35 kV). In such a situation of overvoltage, breakdown of the insulation of the overhead line is possible and, as a result, the network fails.
In order to limit the value of the overvoltage and increase safety, it is necessary to lower the resistance for "current spreading". For this purpose, they install protective grounding on overhead lines (0.4, 6-10, 20 and 35 kV) and outdoor lighting supports.

Features of the procedure

Grounding of metal poles

The ground loop is formed based on what the support was made of. There are currently three designs in use:

• reinforced concrete. Here, in the presence of a network with a grounded neutral, together with the fittings of structures, protection is made out by connecting a special conductor to a grounded wire (zero). The latter should go with a diameter of 6 mm (at least);
• wooden. On wooden supports, pins and hooks are not grounded;

Note! Grounding on wooden poles is installed only when the power line or outdoor lighting systems pass through settlements where there are one- and two-story buildings. A settlement in such a situation should also not have excessively elevated pipes (shielded), trees, etc. Here there is a need to protect the network from atmospheric surges with the help of grounding devices. Their resistance is up to 30 ohms (no more).

• metal supports. Here protection is done by analogy with reinforced concrete structures. These supports are the most common. They are gradually replacing wooden and even reinforced concrete supports from everyday use.

When grounding overhead lines (0.4, 6-10, 20 and 35 kV), the distance between adjacent supports must also be taken into account. Usually the distance between them is 100 or 200 m. This parameter is determined by the average annual number of thunderstorms characteristic of the area.
Be sure to do the grounding of supports (repeated or not) that have a branch to structures where there are a large number of people.
To protect against overvoltage, two types of grounding conductors are used:

• vertical pins that dig vertically into the ground;
• horizontal plates. Such earth electrodes are usually used for stony soils.

The type of grounding conductors is predetermined by the type of soil at the place of mounting of the VL supports (0.4, 6-10, 20 and 35 kV) or outdoor lighting.

How does the procedure itself

Installation of grounding switches

Installation of grounding (repeated or not) for overhead lines (0.4, 6-10, 20 and 35 kV), power transmission networks or outdoor lighting poles is carried out as follows:

• we dig a trench (about 0.5 m). Trench depth up to 1 m is needed for arable land. You need to measure the depth from the beginning of the supports;
• the length of the trench, as well as the number of ground electrodes, must be indicated in the project for the construction of overhead lines (0.4, 6-10, 20 and 35 kV);
• then we perform the immersion of the ground electrodes, forming a contour;
• then welding occurs (either with a rod or a strip);
• after that, the welding joints are protected from possible corrosion.

After the ground loop, a grounding descent is installed. It is made of a steel bar or strip and has the same dimensions as the connection installed between the earth electrodes. The protection circuit is connected to the descent from below. The descent from above is brought to the metal non-conductive parts of the support structure.
This procedure is clearly visible in the figure.

Grounding on a support (wooden):

a - general appearance, b - hook grounding option

A connecting strip (2) and a descent (3) are brought to the wooden support after the contour (ground electrode 1 and 2). Here, the descent is often mounted (pitch - 300 mm), fastened with brackets. In this case, the descent, or rather its upper part (4), will protrude above the support, acting as a lightning rod. Figure (b) shows grounding for a metal pole in a power grid or outdoor lighting. The surge protection circuit here will also be connected to the escapement (1). But in this situation, the escapement will be connected by welding a jumper (2) or bolt clamps that direct the ground potential to the neutral wire (3) and the hook (4).

PUE requirements

PUE is a regulatory documentation that should be relied upon when implementing protective grounding measures (repeated or not) of power transmission network supports or outdoor lighting. The ground loop should always be installed according to these rules to avoid problems later.
The EMP makes the following recommendations:

• in the presence of an electrical installation with a dead-earthed neutral, first of all, it is necessary to ground the neutral wires of the beginning of the overhead line;

Grounding on each support

Grounding on each support

Note! The ground loop in this situation does not need to be installed at the first support. This is due to the fact that here the neutral wire will be tightly connected to the zero point of the power source.

Protective earth:
1 - places for welding; 2 - the ground electrode itself; 3 - conductor to the ground electrode.

• in the presence of electrical installations with a solidly grounded neutral, re-grounding as overvoltage protection should not be installed very often (step - kilometer of the line);
• any subsequent re-grounding must have a resistance of up to 10 ohms (maximum). In the presence of an installation with a capacity of more than 100 kVA. If the power of the installation is lower, then the resistance must be up to 30 ohms (maximum);
• for overhead line supports, grounding devices must be made if repeated overvoltage protection is necessary. It is allowed to use structures for protection against surges of natural origin (lightning). In this situation, the resistance for the grounding device should be taken no higher than 30 ohms;
• any metal structures must be connected to special PEN conductors;
• in the presence of reinforced concrete supports, special PEN conductors must be connected to the fittings of the struts and supports;
• When installing self-supporting insulated wires with insulated carrier conductors, supports (reinforced concrete and metal wooden, for overhead lines) are not subject to overvoltage protection. Here, re-grounding is needed for pins and hooks. This is done in order to form protection against overvoltages of atmospheric origin.

Peculiarities

When forming grounding for overhead lines up to 1 kV, the following nuances should be observed:

• in the presence of a network with a grounded neutral, a jumper is made from an uninsulated conductor for reinforcement of supports (reinforced concrete / metal). It is connected to the neutral wire by means of bolt clamps (branch);
• jumper contact connections must be thoroughly cleaned and coated with petroleum jelly before installation;
• if there is a network with an isolated neutral for the same supports, the installation of protection is carried out by connecting special grounding devices. In this case, the resistance of these structures should not exceed the bar of 50 ohms;
• grounding of structures for creating an outdoor lighting system in the presence of cable power is carried out through the metal sheath of the cable. This happens if there is a grounded neutral.

In other situations, everything is determined by the types of systems, supports and other components.

Conclusion

When creating grounding on various types of supports included in the outdoor lighting system or overhead lines, it is imperative to follow the established rules and recommendations given in the PUE. This is the only way to achieve high-quality and proper grounding, which will protect the poles from damage to the cable insulation and prevent risky situations when people can be shocked when they touch the poles.

Choosing a box for LED strips, correct installation