Complain

Section 4. Switchgears and substations

Chapter 4.2. Switchgears and substations with voltage above 1 kV

Open switchgears

4.2.45. In outdoor switchgears of 110 kV and above, a passage must be provided for mobile assembly and repair mechanisms and devices, as well as mobile laboratories.

4.2.46. The connection of flexible wires in the spans should be carried out by crimping using connecting clamps, and the connections in the hinges at the supports, the connection of branches in the span and the connection to the hardware clamps - by crimping or welding. In this case, the connection of branches in the span is performed, as a rule, without cutting the wires of the span.

Soldering and twisting of wires is not allowed.

Bolted connections are allowed only on the terminals of the apparatus and on the branches to arresters, surge arresters, coupling capacitors and voltage transformers, as well as for temporary installations for which the use of permanent connections requires a large amount of work on rewiring tires.

Strings of insulators for busbar suspension in outdoor switchgear can be single-circuit. If a single-strand garland does not meet the conditions of mechanical stress, then a double-strand one should be used.

Separating (cut-in) garlands are not allowed, with the exception of garlands with the help of which high-frequency minelayers are suspended.

Fastening of flexible bars and cables in tension and suspension clamps with respect to strength shall comply with the requirements given in 2.115.

4.2.47. Joints of rigid busbars in the spans should be done by welding, and the busbars of adjacent spans should be connected using compensating devices connected to the busbars, usually by welding. It is allowed to connect compensating devices to spans using bolted connections.

Branches from rigid tires can be made both flexible and rigid, and their connection to the spans should be performed, as a rule, by welding. Bolted connections are only permitted if justified.

4.2.48. Branches from the switchgear busbars, as a rule, should be located below the busbars.

Suspension of a busbar in one span over two or more sections or busbar systems is not allowed.

4.2.49. Wind and ice loads on tires and structures, as well as design air temperatures, must be determined in accordance with the requirements of building codes and regulations. In this case, the deflection of rigid tires should not exceed 1/80 of the span length.

When determining the loads on structures, it is additionally necessary to take into account the weight of a person with tools and mounting devices when applying:

• tension strings of insulators - 2.0 kN;
• supporting garlands - 1.5 kN;
• support insulators - 1.0 kN.

The pull of the descents to the switchgear devices should not cause unacceptable mechanical stresses and unacceptable convergence of wires under the design climatic conditions.

4.2.50. The design mechanical forces transmitted during short circuit by rigid buses to the support insulators should be taken in accordance with the requirements of Chapter 1.4.

4.2.51. The safety factor of mechanical strength under loads corresponding to 4.2.49 should be taken:

• for flexible tires - at least 3 in relation to their ultimate tensile strength;
• for suspended insulators - at least 4 in relation to the guaranteed minimum breaking load of the whole insulator (mechanical or electromechanical, depending on the requirements of the standards for the type of insulator used);
• for coupling fittings of flexible tires - at least 3 in relation to the minimum breaking load;
• for rigid busbar support insulators - not less than 2.5 in relation to the guaranteed minimum breaking load of the insulator.

4.2.52. Supports for fixing OSG busbars must be calculated as intermediate or end in accordance with Ch.2.5.

4.2.54. The smallest clear distances between non-insulated live parts of different phases, from non-insulated live parts to the ground, grounded structures and fences, as well as between non-insulated live parts of different circuits should be taken according to Table 4.2.5 (Fig. 4.2.3-4.2.12) ...

Table 4.2.5. The smallest clear distances from live parts to various elements of 10-750 kV outdoor switchgear (substations), protected by arresters, and 220-750 kV outdoor switchgear, protected by surge arresters 5, (in the denominator) (Fig. 4.2.3-4.2.12)

Figure number	Distance name	Designation	Insulation distance, mm, for rated voltage, kV
4.2.3 4.2.4 4.2.5	From live parts, equipment and insulation under voltage, to extended earthed structures and to permanent internal fences with a height of at least 2 m, as well as to stationary intercell screens and fire partitions							1800 1200	2500 2000	3750 3300	5500 5000
	From live parts, elements of equipment and insulation, which are energized, to grounded structures: head of the apparatus - support, wire - rack, traverse, wire - ring, rod	A 1 f-3						1600 1200	2200 1800	3300 2700	5000 4500
4.2.3 4.2.4 4.2.11	Between live parts of different phases	A f-f						2000 1600	1800 2200	4200 3400	8000 6500
	From live parts, equipment and insulation under voltage, to permanent internal fences up to 1.6 m high and to transported equipment							2550 2000	3250 3000	4500 4100	6300 5800
	Between live parts of different circuits in different planes with the lower circuit being serviced and the upper circuit not disconnected							3000 2400	4000 3500	5000 3950	7000 6000
	From unshielded live parts to the ground or to the roof of buildings with the greatest sagging of the wires							4500 3900	5000 4700	6450 6000	8200 7200
	Between live parts of different circuits in different planes, as well as between live parts of different circuits horizontally when servicing one circuit and another not disconnected							3600 3200	4200 3800	5200 4700	7000 6500
	From live parts to the upper edge of an external fence or to a building and structure							3800 3200	4500 4000	5750 5300	7500 6500
	From the contact and the knife of the disconnector in the open position to the busbar connected to the second contact							2200 1800	3100 2600	4600 3800	7500 610

1 For insulation elements that are at a distributed potential, the insulation distances should be taken taking into account the actual values ​​of the potentials at different points on the surface. In the absence of data on the potential distribution, it is necessary to conventionally adopt a rectilinear law of the potential drop along the insulation from the full rated voltage (from the side of the live parts) to zero (from the side of the grounded parts).

2 The distance from live parts or insulation elements (from the side of live parts), which are energized, to the dimensions of transformers transported along railways, is allowed to be less than size B, but not less than size A 1 f-3.

3 Distances A f-3, A 1 f-3 and A f-f for 220 kV outdoor switchgear and above, located at an altitude of more than 1000 m above sea level, must be increased in accordance with the requirements of state standards, and the distances A f-f, C and D 1 must be checked against the conditions of the crown limitation.

4 For a voltage of 750 kV, the table gives the distances A ph-ph between parallel wires with a length of more than 20 m; the distances A f-f, between screens, crossing wires, parallel wires up to 20 m long for 750 kV outdoor switchgear with arresters are equal to 7000 mm, and for 750 kV outdoor switchgear with surge arrester - 5500 mm.

5 Surge arresters have a protective level for limiting switching overvoltage phase-to-earth 1.8 U ph.

If, in installations located in high mountains, the distances between the phases increase in comparison with those given in Table 4.2.5 based on the results of the corona test, the distances to the grounded parts must be increased accordingly.

Fig. 4.2.3. The smallest clear distances with rigid tires between live and grounded parts ( A f-3, A 1 f-3) and between live parts of different phases ( A ff)

Fig. 4.2.4. The smallest clear distances with flexible buses between live and grounded parts and between live parts of different phases located in the same horizontal plane

4.2.55. The smallest clear distances with rigid tires (see Fig. 4.2.3.) Between live and grounded parts A f-3 and between live parts of different phases A f-f should be taken according to Table 4.2.5, and for flexible ones (see Figure 4.2.4), it should be determined as follows:

; ; ,

where a = fsina; f- sag of wires at a temperature of +15 ° С, m; a = arc tg PIQ; Q- calculated load from the weight of the wire per 1 m of the wire length, daN / m; P- calculated linear wind load on the wire, daN / m; in this case, the wind speed is taken equal to 60% of the value selected in the calculation of building structures.

4.2.56. The smallest permissible clear distances between adjacent energized phases at the moment of their closest approach under the action of short-circuit currents should be not less than those given in Table 2.5.17, taken at the highest operating voltage.

In a flexible busbar made of several wires in a phase, in-phase spacers should be installed.

4.2.57. The smallest distances from live parts and insulators under voltage to permanent internal fences should be (Table 4.2.5, Figure 4.2.5);

Figure 4.2.5. The smallest distances from live parts and insulation elements under voltage to permanent internal fences

horizontally - not less than size B with a fence height of 1.6 m and not less than the size A f-3 with a fence height of 2.0 m. The second option is recommended for use in the cramped conditions of the substation site;

vertically - not less than size A f-3, measured in the plane of the fence from a point located at a height of 2.7 m from the ground.

4.2.58. Live parts (terminals, buses, slopes, etc.) may not have internal fences if they are located above the level of the planning or ground communication structures at a height not less than values ​​corresponding to the size G according to table 4.2.5 (Figure 4.2.6.).

Figure 4.2.6. The smallest distances from unshielded live parts and from the lower edge of porcelain insulators to the ground

Unshielded live parts connecting the capacitor of high-frequency communication devices, telemechanics and protection devices with the filter must be located at a height of at least 2.5 m. It is recommended to install the filter at a height that allows repair (adjustment) of the filter without removing the voltage from the connection equipment.

Transformers and devices in which the lower edge of the porcelain (polymer material) of the insulators is located above the level of the planning or ground communication facilities at a height of at least 2.5 m are allowed not to be fenced (see Figure 4.2.6). At a lower height, the equipment must have permanent fences that meet the requirements of 4.2.29, located from transformers and apparatus at distances not less than those given in 4.2.57. Instead of permanent fences, it is allowed to install visors to prevent maintenance personnel from touching insulation and live equipment elements.

4.2.59. Distances from unshielded live parts to the dimensions of machines, mechanisms and transported equipment must be at least B according to table 4.2.5 (Figure 4.2.7.).

Figure 4.2.7. The smallest distances from live parts to transported equipment

4.2.60. The distances between the nearest unshielded live parts of different circuits should be selected from the condition of safe service of one circuit with the other not disconnected. When the unshielded live parts of different circuits are located in different (parallel or perpendicular) planes, the vertical distances must be at least the size V, and horizontally - the size D 1 according to Table 4.2.5 (Figure 4.2.8). In the presence of different voltages dimensions V and D 1 are taken at a higher voltage.

Fig. 4.2.8. The smallest distances between live parts of different circuits located in different planes with the maintenance of the lower circuit when the upper circuit is not disconnected

Fig. 4.2.9. The smallest horizontal distances between live parts of different circuits with the maintenance of one circuit while the other is not disconnected

The size V is determined from the service condition of the lower chain with the upper chain not disconnected, and the size D 1 - servicing one circuit while the other is not disconnected. If such maintenance is not provided, the distance between live parts of different circuits in different planes should be taken in accordance with 4.2.53; in this case, the possibility of convergence of wires under operating conditions (under the influence of wind, ice, temperature) must be taken into account.

4.2.61. The distances between live parts and the upper edge of the external fence must be at least the size D according to Table 4.2.5 (Figure 4.2.10).

Fig. 4.2.10. The smallest distances from live parts to the upper edge of the outer fence

4.2.62. The distances from the moving contacts of disconnectors in the open position to the earthed parts must be at least dimensions A f-3 and A 1 f-3; before the busbar of its phase, connected to the second contact, - not less than the size F; before busbar of other connections - not less than size A f-f according to Table 4.2.5 (Figure 4.2.11).

Fig. 4.2.11. The smallest distances from the moving contacts of disconnectors in the open position to grounded and current-carrying parts

4.2.63. The horizontal distances between the live parts of the outdoor switchgear and buildings or structures (indoor switchgear, control room, transformer tower, etc.) must be at least D, and vertically with the greatest sagging of the wires - not less than the size G according to Table 4.2.5 (Figure 4.2.12).

Fig. 4.2.12. The smallest distances between live parts and buildings and structures

4.2.64. The laying of overhead lighting lines, overhead communication lines and signaling circuits above and below the current-carrying parts of the outdoor switchgear is not allowed.

4.2.65. Distances from hydrogen stores to outdoor switchgear, transformers, synchronous compensators must be at least 50 m; to the overhead line supports - at least 1.5 of the support height; to substation buildings with the number of cylinders stored in the warehouse up to 500 pcs. - not less than 20 m, over 500 pcs. - not less than 25 m; to the outer fence of the substation - at least 5.5 m.

4.2.66. Distances from openly installed electrical devices to water coolers of the substation must be at least the values ​​given in Table 4.2.6.

Table 4.2.6. The smallest distance from openly installed electrical devices to water coolers of the substation

For areas with design outside air temperatures below minus 36 ° C, the distances given in Table 4.2.6 should be increased by 25%, and with temperatures above minus 20 ° C, reduced by 25%. For reconstructed objects, the distances given in Table 4.2.6 are allowed to be reduced, but not more than by 25%.

4.2.67. Distances from RF and substation equipment to indoor switchgear buildings and other technological buildings and structures, to KB, STK, SK are determined only by technological requirements and should not increase due to fire conditions.

4.2.68. Fire-prevention distances from oil-filled equipment with an oil mass in a piece of equipment of 60 kg or more to industrial buildings with a category of premises V1-B2, D and D, as well as to residential and public buildings, must be at least:

• 16 m - with the degree of fire resistance of these buildings I and II;
• 20 m - for grade III;
• 24 m - for grade IV and V.

When installing oil-filled transformers with an oil mass of 60 kg or more near the walls of industrial buildings with a room category G and D, electrically connected to the equipment installed in these buildings, distances less than indicated are allowed. Moreover, at a distance of more than 10 m from them and outside the boundaries of sections with a width B(Figure 4.2.13) there are no special requirements for walls, windows and doors of buildings.

Figure 4.2.13. Requirements for open installation of oil-filled transformers near buildings with production facilities of categories D and E

With a distance of less than 10 m to transformers within sections with a width B the following requirements must be met:

1) up to height D(up to the transformer input level) windows are not allowed;

2) at a distance G less than 5 m and degrees of fire resistance of buildings IV and V, the wall of the building must be made according to the I degree of fire resistance and rise above the roof made of combustible material by at least 0.7 m;

3) at a distance G less than 5 m and degrees of fire resistance of buildings I, II, III as well as at a distance G 5 m and more without limitation on fire resistance at a height of d before d + e non-opening windows filled with reinforced glass or glass blocks with frames made of fireproof material are allowed; above d + e- windows opening to the inside of the building, with openings provided with metal grids from the outside with cells of no more than 25x25 mm;

4) at a distance G less than 5 m at a height less than d, and at G 5 m or more at any height, doors made of non-combustible or hardly combustible materials with a fire resistance limit of at least 60 minutes are allowed;

5) ventilation inlets in the wall of the building at a distance G less than 5 m is not allowed; exhaust openings with the release of uncontaminated air within the specified limit are allowed at a height d;

6) at a distance G from 5 to 10 m ventilation openings in the enclosing structures of cable rooms from the side of transformers on an area with a width B not allowed.

The dimensions shown in Figure 4.2.13 a - d and A are taken up to the most protruding parts of the transformers at a height of not more than 1.9 m from the earth's surface. With a unit power of transformers up to 1.6 MVA, distances v≥ 1.5 m; e ≥ 8 m; more than 1.6 MVA v≥ 2 m; e ≥ 10 m distance b taken according to 4.2.217, distance G must be at least 0.8 m.

The requirements of this clause also apply to outdoor KTP.

4.2.69. To prevent oil spreading and fire propagation in case of damage to oil-filled power transformers (reactors) with an amount of oil more than 1 ton per unit, oil receivers, oil outlets and oil collectors must be made in compliance with the following requirements:

1) the dimensions of the oil receiver should protrude beyond the dimensions of the transformer (reactor) by at least 0.6 m with an oil mass of up to 2 tons; 1 m with a mass of 2 to 10 tons; 1.5 m with a mass of 10 to 50 tons; 2 m with a mass of more than 50 tons. In this case, the size of the oil receiver can be taken less than 0.5 m from the side of the wall or partition located from the transformer (reactor) at a distance of less than 2 m;

2) the volume of the oil receiver with the oil drain should be calculated for a one-time reception of 100% of the oil poured into the transformer (reactor).

The volume of the oil receiver without oil drainage should be expected to receive 100% of the volume of oil poured into the transformer (reactor), and 80% of water from fire extinguishing means based on irrigation of the areas of the oil receiver and side surfaces of the transformer (reactor) with an intensity of 0.2 l / s m 2; within 30 minutes;

3) the arrangement of oil receivers and oil outlets should exclude the flow of oil (water) from one oil receiver to another, oil spreading through cable and other underground structures, the spread of fire, clogging of the oil outlet and clogging it with snow, ice, etc .;

4) oil receivers for transformers (reactors) with an oil volume of up to 20 tons can be performed without oil drainage. Oil receivers without oil drainage should be made of a buried structure and closed with a metal grate, on top of which a layer of clean gravel or washed granite crushed stone with a thickness of at least 0.25 m, or non-porous crushed stone of another rock with particles from 30 to 70 mm must be poured. The level of the total volume of oil in the oil receiver must be at least 50 mm below the grate.

Removal of oil and water from the oil receiver without oil drainage should be provided by mobile means. At the same time, it is recommended to perform the simplest device for checking the absence of oil (water) in the oil receiver;

5) oil receivers with oil drainage can be performed both buried and not buried (the bottom is at the level of the surrounding layout). When performing a buried TV receiver, the installation of side fences is not required if this ensures the volume of the oil receiver specified in clause 2.

Oil receivers with oil drainage can be performed:

• with the installation of a metal grate on the oil receiver, on top of which gravel or crushed stone with a layer thickness of 0.25 m is poured;
• without a metal grate with gravel filling on the bottom of the oil receiver with a layer thickness of at least 0.25 m.

An unsubmerged oil receiver should be made in the form of side fences of oil-filled equipment. The height of the side fences should be no more than 0.5 m above the level of the surrounding layout.

The bottom of the oil receiver (buried and not buried) should have a slope of at least 0.005 towards the pit and be covered with purely washed granite (or other non-porous rock) gravel or crushed stone with a fraction of 30 to 70 mm. The backfill thickness must be at least 0.25 m.

The upper level of gravel (crushed stone) must be at least 75 mm below the upper edge of the side (when installing oil receivers with side fences) or the level of the surrounding layout (when installing oil receivers without side fences).

It is allowed not to backfill the bottom of the oil receivers over the entire area with gravel. At the same time, it is necessary to provide for the installation of flame arresters on oil drainage systems from transformers (reactors);

6) when installing oil-filled electrical equipment on a reinforced concrete floor of a building (structure), an oil drain device is mandatory;

7) oil outlets must ensure that oil and water used to extinguish a fire are removed from the oil receiver by automatic stationary devices and hydrants to a safe distance from equipment and structures in terms of fire safety: 50% of oil and the total amount of water must be removed in no more than 0.25 hours Oil drains can be made in the form of underground pipelines or open cuvettes and trays;

8) oil collectors should be of a closed type and should contain the full volume of oil of a single piece of equipment (transformers, reactors) containing the largest amount of oil, as well as 80% of the total (taking into account a 30-minute reserve) water consumption from fire extinguishing means. Oil collectors should be equipped with a water alarm with a signal output to the control panel. The internal surfaces of the oil receiver, oil receiver fencing and oil sump must be protected by an oil-resistant coating.

4.2.70. At substations with transformers 110-150 kV with a unit capacity of 63 MVA and more and transformers of 220 kV and above with a unit capacity of 40 MV network or from an independent source of water supply. Instead of a fire-fighting water pipeline, it is allowed to provide for the intake of water from ponds, reservoirs, rivers and other reservoirs located at a distance of up to 200 m from the substation using mobile fire fighting equipment.

At substations with 35-150 kV transformers with a unit capacity of less than 63 MVA and 220 kV transformers with a unit capacity of less than 40 MVA, a fire-fighting water supply system and a reservoir are not provided.

4.2.71. KRUN and KTP outdoor installation should be located on a planned site at a height of at least 0.2 m from the level of planning with the execution of a platform for maintenance near the cabinets. In areas with a calculated snow cover height of 1.0 m and above and a duration of its occurrence for at least 1 month, it is recommended to install outdoor switchgear and transformer substations at a height of at least 1 m.

The location of the device should ensure convenient rolling out and transportation of transformers and the withdrawable part of the bays.

×

Power equipment

Laying of cables and wires

Protective security measures

Chapter 7.3 Electrical installations in hazardous areas area of ​​application

Definitions

Classification of explosive mixtures according to GOST 12.1.011-78

Categories of explosive mixtures of gases and vapors with air

Groups of explosive mixtures of gases and vapors with air by autoignition temperature

Classification and marking of explosion-proof electrical equipment according to GOST 12.2.020-76 *

Distribution of explosive mixtures by categories and groups

Lower concentration limit of ignition, smoldering temperature, ignition and autoignition of explosive dusts

Explosion-proof electrical equipment groups by field of application

Subgroups of electrical equipment of group II with types of protection "flameproof enclosure" and (or) "intrinsically safe electrical circuit"

Temperature classes for electrical equipment group II

Examples of marking for explosion-proof electrical equipment

Hazardous area classification

Zone class of the room adjacent to the explosive zone of another room

Selection of electrical equipment for hazardous areas. General requirements

Permissible level of explosion protection or degree of protection of the enclosure of electrical machines (stationary and mobile), depending on the class of the hazardous area

Permissible level of explosion protection or degree of protection of the enclosure of electrical devices and devices, depending on the class of the explosive zone

Permissible explosion protection level or degree of protection of electrical luminaires, depending on the class of the hazardous area

Electric cars

Electrical apparatus and devices

Electric hoists

Electric lights

Switchgears, transformer and converter substations

The minimum permissible distance from free-standing ru, tp and pp to rooms with explosive zones and outdoor explosive installations

Electrical wiring, conductors and cable lines

Permissible ways of laying cables and wires in hazardous areas

Minimum permissible distance from conductors (flexible and rigid) and from cable racks with transit cables to rooms with explosive zones and to outdoor explosive installations

Zeroing and grounding

Lightning and ESD protection

Chapter 7.4 electrical installations in fire hazardous areas scope

Definitions. General requirements

Electric cars

The minimum permissible degrees of protection of the enclosures of electrical machines, depending on the class of the fire hazardous zone

Electrical apparatus and devices

The minimum permissible degrees of protection of the shells of electrical devices, devices, cabinets and clamp assemblies, depending on the class of the fire hazardous area

Electric hoists

Minimum permissible degrees of protection for luminaires, depending on the class of the fire hazardous area

Switchgears, transformer and converter substations

Electric lights

Electrical wiring, conductors, air and cable lines

Open ground warehouses for storage of combustible materials and substances, finished products and equipment

The smallest distance from the VL axis to 1 kV with bare wires of aluminum, steel-aluminum or aluminum alloys to the boundaries of open ground warehouses listed in Table. 7.4.4.

Chapter 7.5 electrothermal systems area of ​​application

General requirements

Permissible continuous current of industrial frequency of single-phase conductors from a laminated package of aluminum rectangular buses

Permissible continuous current of industrial frequency of single-phase conductors from a laminated package of rectangular copper buses *

Permissible continuous current of industrial frequency of three-phase conductors from a laminated package of aluminum rectangular buses *

Permissible continuous current of industrial frequency of three-phase conductors from a laminated package of rectangular copper buses *

Permissible continuous current of increased - average frequency of conductors from two aluminum rectangular busbars

Permissible continuous current of increased - average frequency of conductors from two copper rectangular busbars

Permissible continuous current of increased - average frequency of conductors from two aluminum concentric pipes

Permissible continuous current of increased - average frequency of conductors of two concentric copper pipes *

Permissible continuous current of increased - average frequency of cables of the ACG brand for a voltage of 1 kV

Permissible continuous current of increased - average frequency of cables of brand c for a voltage of 1 kV

Insulation resistance of conductors of secondary current leads

The smallest clear distance between the busbars of the secondary current lead *

Characteristics of water for cooling elements of electrothermal installations

Installations of arc furnaces of direct, indirect and combined action (ore-thermal and ferroalloy)

Induction and dielectric heating installations

Installation of electric furnaces (electrothermal devices) of direct and indirect resistance

Electron beam installations

Chapter 7.6 electric welding machines scope. Definitions

General requirements

Requirements for premises for electric welding installations and welding stations

Installations for electric fusion welding (cutting, surfacing)

Electric pressure welding machines

Chapter 7.7 peat electrical installations scope. Definitions

Power supply

Substations

Overhead power lines

Cable lines

Electric motors, switching devices

Earthing

Acceptance of electrical installations into operation

The smallest clear distance between the busbars of the secondary current lead *

The room in which the conductor is laid	Distance, mm, depending on the type of current, frequency and voltage of conductors
	Constant		Variable
							above 10000 Hz
				above 1 to 3 kV		above 1.6 to 3 kV
Dry dust free
Dry dusty **

* With a tire height up to 250 mm; at higher heights, the distance should be increased by 5-10 mm.

** Non-conductive dust.

7.5.28. Sewerage of water, cooling equipment, apparatus and other elements of electrothermal installations should be performed taking into account the possibility of monitoring the state of the cooling system.

It is recommended to install the following relays: pressure, jet and temperature (the last two - at the outlet of water from the elements cooled by it) with their work on a signal. In the event that interruption of the flow or overheating of the cooling water can lead to emergency damage, an automatic shutdown of the unit must be ensured.

The water cooling system - open (from the water supply network or from the enterprise's recycling water supply network) or closed (double-circuit with heat exchangers), individual or group - should be selected taking into account the water quality requirements specified in the standards or technical conditions for the equipment of an electrothermal installation. When choosing a system, one should proceed from the specific conditions of the water supply of the enterprise (workshop, building) and the most economically feasible option, determined by the minimum of the reduced costs.

Water-cooled elements of electrothermal installations with an open-loop cooling system must be designed for a maximum water pressure of 0.6 MPa (6 kgf / cm) and a minimum 0.2 MPa (2 kgf / cm) with water quality, as a rule, meeting the requirements of table. 7.5.13, unless other normative values ​​are given in the standards or technical specifications for the equipment.

Table 7.5.13

Characteristics of water for cooling elements of electrothermal installations

Index	Type of water supply network
	Domestic drinking water supply	Water recycling network of the enterprise
Hardness, mg-eq / l, no more:
carbonate
suspended solids (turbidity)
active chlorine
Temperature, ° С, no more

In electrothermal installations, for the cooling of the elements of which water from the circulating water supply network is used, it is recommended to provide mechanical filters to reduce the content of suspended particles in the water.

When choosing an individual closed water cooling system, it is recommended to provide for a secondary circuit of water circulation without a backup pump, so that if the operating pump fails, water from the water supply network is used for the time required for an emergency stop of the equipment.

When using a group closed water cooling system, it is recommended to install one or two standby pumps with automatic standby.

7.5.29. When cooling elements of an electrothermal installation, which may be energized, with water through a flow-through or circulation system, insulating hoses (sleeves) must be provided to prevent potential leakage through the pipelines, which is dangerous for the operating personnel. If there is no fence, then the supply and drain ends of the hose must have grounded metal nozzles, excluding personnel touching them when the unit is turned on.

The length of the insulating water cooling hoses connecting elements of different polarity must be at least as specified in the technical documentation of the equipment manufacturers; in the absence of such data, the length is recommended to be taken equal: at a rated voltage of up to 1 kV, at least 1.5 m with an inner diameter of hoses up to 25 mm and 2.5 m with a diameter of 25 to 50 mm, at a rated voltage above 1 kV - 2 , 5 and 4 m, respectively.

The length of the hoses is not standardized if there is a break between the hose and the drain pipe and the water jet falls freely into the funnel.

7.5.30. Electrothermal installations, the equipment of which requires operational maintenance at a height of 2 m or more from the floor level of the room, must be equipped with working platforms, fenced with railings, with permanent ladders. The use of movable (eg telescopic) ladders is not permitted. In an area where personnel can touch live parts of equipment, platforms, fences and ladders should be made of non-combustible materials, the platform flooring should be covered with a non-combustible dielectric material.

7.5.31. Pump-accumulator and oil-pressure units of hydraulic drive systems of electrothermal equipment, containing 60 kg of oil and more, should be located in rooms where emergency oil removal is ensured.

7.5.32. Vessels used in electrothermal installations operating at pressures above 70 kPa (0.7 kgf / cm), devices using compressed gases, as well as compressor installations must meet the requirements of the current rules approved by the Gosgortekhnadzor of Russia.

7.5.33. The gases from the exhaust of the pre-vacuum pumps, as a rule, must be removed outside, the release of these gases into production and other similar premises is not recommended.

"

(substations) 3-330 kV, protected by arresters, and 110-330 kV indoor switchgear, protected by surge arresters 1, (in the denominator) (Fig. 4.2.14-4.2.17)

Figure number	Distance name	Designation	Insulation distance, mm, for rated voltage, kV
	From live parts to grounded structures and parts of buildings
	Between conductors of different phases
	From live parts to solid fences
	From live parts to mesh fences
	Between unshielded live parts of different circuits
	From unshielded live parts to the floor
	From unenclosed outlets from the closed switchgear to the ground when they exit outside the territory of the open switchgear and in the absence of transport passage under the outlets
	From the contact and the knife of the disconnector in the open position to the busbar connected to the second contact
	From unshielded cable outlets from the closed switchgear to the ground when cables exit to a support or portal outside the territory of the open switchgear and in the absence of vehicle passage under the outlets

1 Surge arresters have a phase-to-earth switching overvoltage protection level of 1.8 U f.

4.2.91. The width of the service corridor for switchgear with withdrawable elements and KTP should ensure ease of control, moving and turning the equipment and its repair.

When installing switchgear and KTP in separate rooms, the width of the service corridor should be determined based on the following requirements:

for single row installation - length of the largest of the switchgear bogies (with all protruding parts) plus at least 0.6 m;

with two-row installation - length of the largest of the switchgear bogies (with all protruding parts) plus at least 0.8 m.

If there is a corridor on the back side of the switchgear and KTP for their inspection, its width should be at least 0.8 m; individual local narrowings are allowed no more than 0.2 m.

With an open installation of switchgear and transformer substations in industrial premises, the width of the free passage should be determined by the location of the production equipment, ensure the possibility of transporting the largest elements of the switchgear to the transformer substation, and in any case, it should be at least 1 m.

The height of the room must be at least the height of the switchgear, KTP, counting from busbar inputs, jumpers or protruding parts of the cabinets, plus 0.8 m to the ceiling or 0.3 m to the beams.

A lower height of the room is allowed if this ensures the convenience and safety of replacement, repair and adjustment of equipment for switchgear, KTP, bus bushings and jumpers.

4.2.92. The calculated loads on the floors of the premises along the path of transportation of electrical equipment should be taken taking into account the mass of the heaviest equipment (for example, a transformer), and the openings should correspond to their dimensions.

4.2.93. With air inputs to indoor switchgear, KTP and closed substations that do not cross passages or places where traffic is possible, etc., the distance from the lowest point of the wire to the earth's surface must be at least the size E(Table 4.2.7 and Fig. 4.2.17).

At smaller distances from the wire to the ground, in the corresponding area under the input, either the area should be fenced with a 1.6 m high fence, or a horizontal fence under the input. In this case, the distance from the ground to the wire in the plane of the fence should be at least the size E.

For air inputs crossing passages or places where traffic is possible, etc., the distance from the lowest point of the wire to the ground should be taken in accordance with 2.5.212 and 2.5.213.

When air outlets from the closed switchgear to the territory of the outdoor switchgear, the indicated distances should be taken according to table. 4.2.5 for size G(see fig. 4.2.6).

The distances between adjacent line terminals of two circuits must be at least the values ​​given in table. 4.2.3 for size D if no partitions are provided between the terminals of adjacent circuits.

On the roof of the indoor switchgear building in the event of an unorganized drainage over the air inlets, visors should be provided.

4.2.94. Exits from the RI should be carried out on the basis of the following requirements:

1) with a switchgear length up to 7 m, one exit is allowed;

2) if the length of the switchgear is more than 7 to 60 m, two exits at its ends must be provided; it is allowed to place exits from the switchgear at a distance of up to 7 m from its ends;

3) with a switchgear length of more than 60 m, in addition to exits at its ends, additional exits must be provided so that the distance from any point of the service corridor to the exit is no more than 30 m.

Exits can be made to the outside, to the staircase or to another industrial premises of category G or D, as well as to other compartments of the switchgear, separated from this by a fire door of II degree of fire resistance. In multi-storey switchgears, the second and additional exits can also be provided to a balcony with an external fire escape.

The gates of cells with a sash width of more than 1.5 m must have a wicket if they are used for the exit of personnel.

4.2.95. It is recommended to make the floors of the switchgear premises over the entire area of ​​each floor at one level. The construction of the floors must exclude the possibility of the formation of cement dust. Thresholds in doors between separate rooms and in corridors are not allowed (for exceptions, see 4.2.100 and 4.2.103).

4.2.96. Doors from RU must open in the direction of other rooms or outward and have self-locking locks that can be opened without a key from the RU

Doors between compartments of one switchgear or between adjacent rooms of two switchgears must have a device that fixes the doors in the closed position and does not prevent the doors from opening in both directions.

Doors between rooms (compartments) of switchgear of different voltages must open towards switchgear with lower voltage.

Locks in the doors of premises of switchgear of the same voltage must be opened with the same key; keys from the entrance doors of the switchgear and other premises should not fit the camera locks, as well as the door locks in the fences of electrical equipment.

The requirement to use self-locking locks does not apply to switchgears of urban and rural distribution electrical networks with a voltage of 10 kV and below.

4.2.97. The enclosing structures and partitions of the switchgear and KTP for auxiliary needs of the power plant should be made of non-combustible materials.

It is allowed to install switchgear and transformer substations for own needs in the technological rooms of substations and power plants in accordance with the requirements of 4.2.121.

4.2.98. In one room of the switchgear with a voltage of 0.4 kV and above, it is allowed to install up to two oil transformers with a capacity of up to 0.63 MVA each, separated from each other and from the rest of the switchgear room by a partition made of non-combustible materials with a fire resistance limit of 45 minutes, at least the height of the transformer, including the high voltage bushings.

4.2.99. Devices related to starting devices for electric motors, synchronous compensators, etc. (switches, starting reactors, transformers, etc.) may be installed in a common chamber without partitions between them.

4.2.100. Voltage transformers, regardless of the mass of oil in them, are allowed to be installed in fenced RU chambers. In this case, a threshold or ramp must be provided in the chamber, designed to hold the full volume of oil contained in the voltage transformer.

4.2.101. The switch compartments should be separated from the service corridor by solid or mesh fences, and from each other by solid partitions made of non-combustible materials. These switches must be separated from the drive by the same partitions or shields.

Under each oil switch with an oil mass of 60 kg or more in one pole, an oil receiver device for the full volume of oil in one pole is required.

4.2.102. In closed, free-standing, attached and built-in substations, in the chambers of transformers and other oil-filled apparatus with an oil mass in one tank up to 600 kg when the chambers are located on the ground floor with doors going out, oil collecting devices are not performed.

If the mass of oil or a non-combustible environmentally friendly dielectric in one tank is more than 600 kg, an oil receiver must be arranged, designed for the full volume of oil, or for holding 20% ​​of the oil with a drain to the oil sump.

4.2.103. When constructing chambers above the basement, on the second floor and above (see also 4.2.118), as well as when arranging an exit from the chambers into the corridor under transformers and other oil-filled apparatuses, oil receivers should be performed in one of the following ways:

1) with an oil mass in one tank (pole) up to 60 kg, a threshold or ramp is performed to hold the full volume of oil;

2) with an oil mass of 60 to 600 kg, an oil receiver is made under the transformer (apparatus), designed for the full volume of oil, or at the exit from the chamber - a threshold or ramp to hold the full volume of oil;

3) with an oil mass of more than 600 kg:

oil receiver containing at least 20% of the total oil volume of the transformer or apparatus, with oil drainage into the oil sump. The oil drain pipes from the oil receivers under the transformers must have a diameter of at least 10 cm. On the side of the oil receivers, the oil drain pipes must be protected with nets. The bottom of the oil receiver should have a slope of 2% towards the sump;

oil receiver without oil drainage into the oil sump. In this case, the oil receiver should be covered with a grating with a 25 cm layer of clean washed granite (or other non-porous rock) gravel or crushed stone with a fraction of 30 to 70 mm and should be designed for the full volume of oil; the oil level should be 5 cm below the grate. The top level of gravel in the oil receiver under the transformer should be 7.5 cm below the air inlet opening. The area of ​​the oil receiver should be larger than the area of ​​the base of the transformer or apparatus.

4.2.104. Ventilation of the premises of transformers and reactors should ensure the removal of the heat emitted by them in such quantities that under their load, taking into account the overload capacity and the maximum design ambient temperature, the heating of transformers and reactors does not exceed the maximum permissible value for them.

Ventilation of the premises of transformers and reactors should be performed in such a way that the temperature difference between the air leaving the room and entering it does not exceed: 15 ° C for transformers, 30 ° C for reactors for currents up to 1000 A, 20 ° C for reactors for currents over 1000 A.

If it is impossible to provide heat exchange with natural ventilation, it is necessary to provide for forced ventilation, while control of its operation using signaling devices should be provided.

4.2.105. Supply and exhaust ventilation with a fence at floor level and at the level of the upper part of the room should be carried out in the room where the switchgear and SF6 gas cylinders are located.

4.2.106. The rooms of the switchgear containing equipment filled with oil, SF6 gas or a compound must be equipped with exhaust ventilation switched on from the outside and not connected with other ventilation devices.

In places with low winter temperatures, supply and exhaust ventilation openings should be equipped with insulated valves that can be opened from the outside.

4.2.107. In rooms in which the personnel on duty is 6 hours or more, the air temperature must be at least +18 ° C and not higher than +28 ° C.

In the repair area of ​​the indoor switchgear, during the repair work, the temperature must be at least +5 ° С.

When heating rooms in which there is gas-insulated equipment, heating devices with a heating surface temperature exceeding 250 ° C (for example, heaters of the TEN type) should not be used.

4.2.108. Openings in the enclosing structures of buildings and premises after laying conductors and other communications should be sealed with a material that ensures fire resistance not lower than the fire resistance of the enclosing structure itself, but not less than 45 minutes.

4.2.109. Other openings in the outer walls to prevent the entry of animals and birds must be protected with nets or gratings with cells of 10x10 mm.

4.2.110. Overlapping cable ducts and double floors should be made of removable plates of non-combustible materials, flush with the clean floor of the room. The mass of an individual floor slab should be no more than 50 kg.

4.2.111. Laying in chambers of devices and transformers of transit cables and wires, as a rule, is not allowed. In exceptional cases, it is allowed to lay them in pipes.

Electrical wiring for lighting and control and measurement circuits located inside chambers or located near non-insulated live parts may only be allowed to the extent necessary for making connections (for example, to instrument transformers).

4.2.112. Laying of heating pipelines related to them (not transit) into the premises of the switchgear is allowed provided that one-piece welded pipes are used without valves, etc., and welded ventilation ducts - without valves and other similar devices. Transit laying of heating pipelines is also allowed, provided that each pipeline is enclosed in a continuous waterproof shell.

4.2.113. When choosing a switchgear circuit containing gas-insulated devices, simpler circuits should be used than in an air-insulated switchgear.

Electrical Installation Rules (PUE)

SCOPE, DEFINITIONS

4.2.1. This chapter of the Rules applies to stationary switchgear and alternating current substations with voltage above 1 kV. The rules do not apply to special switchgear and substations, regulated by special technical conditions, and to mobile electrical installations.

4.2.2. A switchgear is an electrical installation that serves to receive and distribute electricity and contains switching devices, busbars and connecting buses, auxiliary devices (compressor, battery, etc.), as well as protection devices, automation and measuring devices.

An open switchgear (OSG) is called a switchgear, all or the main equipment of which is located in the open air.

A closed switchgear (ZRU) is called a switchgear, the equipment of which is located in the building.

4.2.3. A complete switchgear is called a switchgear, consisting of fully or partially closed cabinets or blocks with built-in devices, protection and automation devices, supplied assembled or fully prepared for assembly.

A complete switchgear designed for indoor installation is abbreviated as KRU. Complete switchgear designed for outdoor installation is abbreviated as KRUN.

4.2.4. A substation is an electrical installation that converts and distributes electricity and consists of transformers or other energy converters, switchgear, control devices and auxiliary structures.

Depending on the predominance of one or another function of substations, they are called transformer or converter.

4.2.5. An attached substation (attached switchgear) is a substation (switchgear) directly adjacent (adjacent) to the main building.

4.2.6. A built-in substation (built-in switchgear) is a closed substation (closed switchgear) inscribed (inscribed) into the circuit of the main building.

4.2.7. An in-shop substation is a substation located inside a production building (open or in a separate closed room).

4.2.8. A complete transformer (converter) substation is a substation consisting of transformers (converters) and blocks (switchgear or switchgear and other elements) supplied assembled or fully prepared for assembly. Complete transformer (converter) substations (KTP, KPP) or their parts installed in an enclosed space refer to indoor installations, installed in the open air - to outdoor installations.

4.2.9. A pole (mast) transformer substation is an open transformer substation, all equipment of which is installed on structures or on overhead line supports at a height that does not require a substation fencing.

4.2.10. Distribution point(RP) is called a switchgear designed to receive and distribute electricity at one voltage without conversion and transformation, which is not part of the substation.

4.2.11. A chamber is a room for installing devices and tires.

A closed chamber is a chamber that is closed on all sides and has solid (not mesh) doors.

A fenced chamber is a chamber that has openings protected in whole or in part by non-continuous (mesh or mixed) fences.

Mixed fences are mesh and solid sheet fences.

An explosion chamber is a closed chamber designed to localize possible emergency consequences in the event of damage to the devices installed in it and having an exit to the outside or to the explosion corridor.

4.2.12. A service corridor is a corridor along the cameras or cabinets of the switchgear designed for servicing devices and buses.

The blast corridor is the corridor into which the blast chamber doors open.

GENERAL REQUIREMENTS

4.2.13. Electrical equipment, live parts, insulators, fasteners, fences, supporting structures, insulating and other distances should be selected and installed in such a way that:

1) forces caused by normal operating conditions of the electrical installation, heating, electric arc or other phenomena accompanying its operation (sparking, gas emission, etc.) could not lead to damage to the equipment and the occurrence of a short circuit or ground fault, as well as harm the maintenance personnel ;

2) in case of violation of the normal operating conditions of the electrical installation, the necessary localization of damage caused by the action of the short circuit was ensured;

3) when the voltage is removed from any circuit, the devices, live parts and structures related to it could be safely inspected, replaced and repaired without breaking normal work adjacent chains;

4) the possibility of convenient transportation of equipment was provided.

The requirements of clause 3 do not apply to switchgear of the type of assemblies above 1 kV in substations, which are repaired when the entire switchgear is turned off.

4.2.14. When using open knife disconnectors or open knife separators to turn off and turn on the current of unloaded transformers, charging or equalizing current of power lines, earth fault current, the distances between live parts and from live parts to the ground must comply with the requirements of this chapter and special directive documents approved in established order.

4.2.15. The selection of devices, conductors and insulators for short circuit conditions should be made in accordance with Ch. 1.4.

4.2.16. The structures on which the electrical equipment specified in 4.2.15 is installed and fixed must withstand loads and effects from the weight of the equipment, wind, ice, as well as those arising from short circuits.

Building structures located near live parts and accessible to the touch of personnel should not heat up from the influence of electric current to a temperature of 50 ° C and above; inaccessible to touch - up to 70 ° C and above.

Structures may not be checked for heating if an alternating current of 1000A or less passes through the current-carrying parts located near them.

4.2.17. All circuits of the switchgear should provide for the installation of disconnecting devices with a visible gap, providing the ability to disconnect all devices (switches, separators, fuses, current transformers, voltage transformers, etc.) of each circuit from the busbars, as well as from other voltage sources.

This requirement does not apply to switchgear and switchgear cabinets with withdrawable trolleys, high-frequency interrupters and coupling capacitors, voltage transformers installed on outgoing lines, arresters installed on the terminals of transformers and on outgoing lines, as well as on power transformers with cable entries.

In some cases, due to design or circuit considerations, it is allowed to install current transformers up to the disconnector that disconnects the rest of the circuit devices from voltage sources.

4.2.18. The switch or its actuator must have a clearly visible and reliably working position indicator ("on", "off"). The use of signal lamps as the only indicators of the position of the switch is not allowed. If the switch has no open contacts and its drive is separated by a wall from the switch, then the indicator should be both on the switch and on the drive.

4.2.19. When the switchgear and substations are located in places where the air can contain substances that impair the performance of insulation or have a destructive effect on equipment and buses, measures must be taken to ensure reliable operation of the installation: reinforced insulation is applied; tires made of material resistant to environmental influences are used, or they are painted with a protective coating; RU and substations are located on the side of the prevailing wind direction; Switchgear and substations are made according to the simplest schemes; closed version of switchgear and substations, protected from the penetration of dust, harmful gases or vapors into the room.

When constructing outdoor switchgear near sea coasts, salt lakes, chemical plants, as well as in places where long-term operating experience has established the destruction of aluminum from corrosion, special aluminum and steel-aluminum wires protected from corrosion should be used.

4.2.20. When switchgear and substations are located at an altitude of more than 1000 m above sea level, air insulation gaps, suspension insulation and external insulation of electrical equipment should be selected in accordance with the requirements given in 4.2.53, 4.2.54, 4.2.82, 4.2.83, taking into account corrections to compensate for the decrease in the dielectric strength of the insulation at a reduced atmospheric pressure.

4.2.21. In outdoor switchgear, KRUN and in unheated indoor switchgear, where the ambient temperature can be below minus 25 ° C, oil heating of oil switches should be provided.

In addition, regardless of the minimum temperature, heating of the mechanisms of drives of oil and air switches, valve blocks of air switches, their unit cabinets, as well as other cabinets in which equipment or indoor clamps are used, should be provided.

Heated relay and measuring instruments must be carried out in accordance with the requirements given in GOST, heating of meters - in accordance with 1.5.27 and 1.5.28.

4.2.22. Busbar of switchgear and substations should be performed, as a rule, from aluminum, steel-aluminum and steel wires, strips, pipes and tires made of aluminum profiles and aluminum alloys for electrical purposes.

The conductors should be made in accordance with the requirements of Ch. 2.2.

4.2.23. The designation of the phases of electrical equipment and busbars of switchgear and substations must be carried out in accordance with the requirements of Ch. 1.1.

4.2.24. Switchgears 3 kV and above must be equipped with an operational interlock, which excludes the possibility of:

switching on switches, separators and disconnectors for earthing knives and short-circuits;

switching on grounding knives on the busbar, not separated by disconnectors from the busbar, which is energized;

disconnection and switching on by separators and disconnectors of the load current, if this is not provided for by the design of the device.

It is allowed to install only a mechanical interlock with a disconnector drive and a device for locking the grounding knives with locks in the off position on the earthing knives of the line disconnectors on the line side.

For RU with simple schemes electrical connections, it is recommended to use a mechanical (key) operational blocking, and in all other cases - electromagnetic. Disconnector drives, accessible to unauthorized persons, must have devices for locking them with locks in the open and closed positions.

4.2.25. Switchgears and substations above 1 kV must be equipped with stationary grounding blades, which ensure, in accordance with safety requirements, grounding of devices and busbars, as a rule, without the use of portable grounding.

Grounding blades should be painted black. The handles of the earthing knife drives should be painted red and the handles of the other drives in the equipment colors.

In places where stationary grounding knives cannot be used, contact surfaces must be prepared on current-carrying and grounding buses for connecting portable grounding conductors.

In the presence of voltage transformers, the busbars should be earthed, as a rule, by the earthing knives of the voltage transformer disconnectors.

4.2.26. Mesh and mixed fences of live parts and electrical equipment must have a height above the level of the layout for outdoor switchgear and openly installed transformers of 2 or 1.6 m (subject to the requirements of 4.2.57 and 4.2.58), and above the floor level for indoor switchgear and transformers installed inside buildings, 1.9 m; nets must have holes of at least 10x10 mm and no more than 25x25 mm, as well as devices for locking them with a lock. The lower edge of these fences in the outdoor switchgear should be located at a height of 0.1-0.2 m, and in the indoor switchgear - at the floor level.

External barriers should be made in accordance with the requirements given in 4.2.39.

The use of barriers is allowed when entering the chambers of switches, transformers and other devices for examining chambers in the presence of voltage on live parts. Barriers should be installed at a height of 1.2 m and be removable. If the floor of the cells is more than 0.3 m above the ground level, it is necessary to leave a distance of at least 0.5 m between the door and the barrier, or provide a platform in front of the door for inspection.

4.2.27. In the case when deformations of wires (tires) caused by changes in temperature, vibration, etc., can cause dangerous mechanical stresses in wires or insulators, measures should be taken to exclude the occurrence of such stresses (compensators, weakened tension, etc.) ...

4.2.28. Indicators of the level and temperature of oil of oil-filled transformers and apparatus and other indicators characterizing the condition of the equipment should be located in such a way as to provide convenient and safe conditions for access to them and monitoring them without removing the voltage (for example, from the side of the passage to the chamber) ...

For oil sampling, the distance from the floor level or the surface of the earth to the crane of the transformer or apparatus must be at least 0.2 m or an appropriate pit must be provided.

4.2.29. The wiring of the protection, measurement, signaling and lighting circuits laid through oil-filled electrical devices must be made with oil-resistant insulation.

4.2.30. Outdoor transformers, reactors and condensers should be painted in light colors with weather and oil resistant paints to reduce heat from direct sunlight.

4.2.31. Switchgears and substations must be equipped with electric lighting. Lighting fixtures must be installed in such a way that they can be safely serviced.

4.2.32. Switchgear and substations must be provided with telephone connection in accordance with the adopted service system.

4.2.33. The placement of switchgear and substations, the general plan and engineering preparation of the territory and their protection from flooding, landslides, avalanches, etc. must be performed in accordance with the requirements of the SNiP of the Gosstroy of Russia.

4.2.34. The layout and design of outdoor switchgear and indoor switchgear should provide for the possibility of using mechanisms, including special ones, for the production of installation and repair work.

4.2.35. The distances between switchgear (substations) and trees with a height of more than 4 m should be such that damage to equipment and busbars is excluded when a tree falls.

4.2.36. For switchgears and substations located in the area of ​​residential and industrial buildings, measures should be taken to reduce the noise generated by operating electrical equipment (transformers, synchronous compensators, etc.) to the values ​​specified in SNiP II-12-77 of the Gosstroy of Russia.

4.2.37. Switchgears and substations with permanent personnel on duty, with operational and repair personnel constantly on them, as well as in the presence of residential buildings nearby, must be provided with drinking water by arranging a drinking water supply system, constructing artesian wells or wells.

4.2.38. For switchgears and substations with constant duty of personnel with a water supply, insulated latrines with sewerage should be arranged. In the absence of sewer mains near substations, it is allowed to perform local sewer devices (sedimentation tanks, filters). For substations without constant personnel on duty, it is allowed to install non-insulated latrines with watertight cesspools.

When substations of 110 kV and above are located without constant personnel on duty near existing systems water supply and sewerage (at a distance of up to 0.5 km) in the building of the general substation control center (OCP), sanitary sewerage units should be provided.

4.2.39. The territory of the outdoor switchgear and the substation should be fenced with an external fence 1.8-2.0 m high. External fences with a height of more than 2.0 m can be used in places with high snow drifts, as well as for substations with a special regime of admission to their territory.

Auxiliary structures (workshops, warehouses, control rooms, etc.) located on the territory of the outdoor switchgear should be fenced off with an internal fence with a height of 1.6 m.

When an outdoor switchgear (substation) is located on the territory of power plants, these outdoor switchgear (substations) must be fenced with an internal fence with a height of 1.6 m.

Fences can be solid, mesh or lattice.

Fences may not be provided:

for closed substations located in the protected area of ​​an industrial enterprise;

for closed substations located on the territory of cities and towns;

for pole substations (see also 4.2.134).

4.2.40. Metal structures of indoor switchgear, outdoor switchgear and substations, as well as underground parts of metal and reinforced concrete structures must be protected from corrosion.

4.2.41. For the territory of outdoor switchgear and substations, in which, under normal operating conditions, oil leaks from the oil control room, from oil depots, from machine rooms, as well as from transformers and switches during repair and other work, oil leaks must be provided for its collection and removal from in order to exclude the possibility of oil getting into water bodies.

4.2.42. As an operating current at substations, alternating current should be used in all cases where this is possible and leads to a simplification and reduction in the cost of electrical installations while ensuring the necessary reliability of their operation.

OPEN SWITCHING DEVICES

4.2.43. In outdoor switchgears of 110 kV and above, there should be a passage along the circuit breakers for mobile installation and repair mechanisms and devices, as well as mobile laboratories; the passage gauge must be at least 4 m in width and height.

For outdoor switchgear on the territories of industrial enterprises in cramped conditions, the requirements of this paragraph are not mandatory.

4.2.44. The connection of flexible wires in the spans should be carried out, as a rule, by crimping, and the connection in the loops at the supports, the connection of branches in the span and the connection to the hardware clamps - by welding or crimping. In this case, the connection of branches in the span should be carried out without cutting the wires of the span.

Soldering and twisting of wires is not allowed.

Bolted connection is allowed only on the terminals of the apparatus and on the branches to the arresters, coupling capacitors and voltage transformers, as well as for temporary installations, for which the use of permanent connections requires a large amount of work to rewire the tires.

Strings of insulators for busbar suspension in outdoor switchgear can be single-circuit. If a single-strand garland does not meet the conditions of mechanical stress, then a double-strand one should be used.

Separating (cut-in) garlands are not allowed, with the exception of garlands with the help of which high-frequency minelayers are suspended.

Fastening of flexible bars and cables in tension and suspension clamps with respect to strength shall comply with the requirements given in 2.5.82, 2.5.84 and 2.5.85.

4.2.45. Branches from the switchgear busbars, as a rule, should be located below the busbars. Suspension of a busbar in one span over two or more sections or busbar systems is not allowed.

4.2.46. Loads on tires and structures from wind and ice, as well as design air temperatures must be determined in accordance with the requirements of Ch. 2.5.

When determining the loads on flexible tires, the weight of the string of insulators and descents to devices and transformers should also be taken into account.

When determining the loads on structures, additional loads from the mass of a person with a tool and mounting devices should be taken into account: 200 kg - when using strings of insulators for anchor supports and 150 kg - for intermediate ones; 100 kg - with support insulators.

The pull of the slopes from the tires to the outdoor switchgear devices should not cause unacceptable mechanical stresses at low temperatures and unacceptable convergence of wires in strong winds.

4.2.47. The mechanical safety factor for flexible tires under loads complying with the requirements given in 4.2.46 shall be at least 3 in relation to their ultimate tensile strength.

4.2.48. The safety factor of mechanical strength for suspended insulators under loads corresponding to the requirements given in 4.2.46 must be at least 4 in relation to the guaranteed minimum breaking load of the whole insulator (mechanical or electromechanical, depending on the requirements of GOST for the type of insulator used).

4.2.49. The design mechanical forces transmitted during a short circuit by rigid buses to the support insulators should be taken in accordance with 1.4.15.

4.2.50. The safety factor of mechanical strength in coupling fittings for flexible tires under loads complying with the requirements given in 4.2.46 shall be at least 3 in relation to the minimum breaking load.

4.2.51. Supports for suspension of outdoor switchgear tires must be made of prefabricated reinforced concrete or steel.

4.2.52. Supports for fixing OSG busbars are made and calculated as intermediate or end in accordance with the requirements given in Ch. 2.5. Intermediate supports, temporarily used as end supports, should be reinforced with guy wires.

4.2.53. The number of suspension and support insulators, external insulation of the switchgear electrical equipment are selected in accordance with the "Instruction for the design of insulation in areas with a clean and polluted atmosphere.

4.2.54. Distances in the light with rigid buses between live and grounded parts and between live parts of different phases must be at least the values ​​given in table. 4.2.2 (fig. 4.2.1).

Rice. 4.2.1. The smallest clear distances with rigid tires between live and grounded parts ()
and between live parts of different phases ()

If, in high-altitude installations, the distances between the phases increase in comparison with those given in table. 4.2.2 Based on the corona test, the distances to earthed parts must be increased accordingly.

Table 4.2.1

Number of busbar insulators

Insulator type	Number of insulators, pcs., At voltage, kV
PF6-B (PM-4.5)
PS6-A (PS-4.5)
SHN-10; ONSH-10 (ISHD-10);
ONS-10-500; ONS-10-2000;
ONS-20-500; ONS-20-2000
ONSH-35-1000 (SHT-35)
ONSH-35-2000 (ISHD-35)

Table 4.2.2.

The smallest distance from live parts to various elements of outdoor switchgear (substations) in the light according to Fig. 4.2.1-4.2.10

	Distance name	Designation	Insulation distance, mm, for rated voltage, kV
4.2.1; 4.2.2; 4.2.3	From live parts or from elements of equipment and insulation that are energized to grounded structures or permanent internal fences with a height of at least 2 m
	Between wires of different phases
4.2.3; 4.2.5; 4.2.9	From live parts or from elements of equipment and insulation that are energized, to permanent internal fences 1.6 m high, to the dimensions of the transported equipment
	Between live parts of different circuits in different planes with the lower circuit being serviced and the upper circuit not disconnected
	From unshielded live parts to the ground or to the roof of buildings with the greatest sagging of the wires
4.2.6; 4.2.7; 4.2.8; 4.2.10	Between live parts of different circuits in different planes, as well as between live parts of different circuits horizontally when servicing one circuit and a non-disconnected other, from live parts to the upper edge of an external fence, between live parts and buildings or structures							where is the sag of the wire at a temperature of plus 15 ° C, m; ; - wire weight per 1 m of length, daN / m; P - high-speed wind pressure per 1 m of wire length, daN / m; in this case, the wind speed is taken equal to 60% of the value selected in the calculation of building structures. Rice. 4.2.2. The smallest clear distances with flexible buses between live and grounded parts and between live parts of different phases located in the same horizontal plane 4.2.56. At three-phase short-circuit currents of 20 kA and more flexible switchgear busbars, it is necessary to check to exclude the possibility of collision or phase convergence, which is dangerous with respect to breakdown, as a result of the dynamic action of the short-circuit current. The smallest permissible clear distances between adjacent energized phases at the moment of their closest approach under the action of short-circuit currents must correspond to the smallest air gaps on the overhead line, taken at the highest operating voltage and given in Ch. 2.5. In flexible conductors made of several wires per phase, spacers must be installed. 4.2.57. The horizontal distances from live and ungrounded parts or insulation elements (from the side of live parts) to permanent internal fences, depending on their height, must be at least the values ​​given in table. 4.2.2 for size B with a guardrail height of 1.6 m and for size with a guardrail height of 2 m.When these parts or elements are located above the barriers, these distances must be maintained above the barriers up to a height of 2.7 m in the plane of the barrier (Fig. 4.2.3). Rice. 4.2.3. The smallest distances from live parts and insulation elements that are energized, to permanent internal fences The distances from a point located at a height of 2.7 m in the plane of the fence to these parts or elements must be at least (Figure 4.2.3). 4.2.58. Live parts (terminals, buses, slopes, etc.) may not have internal fences if they are located above the level of the planning or the level of the structure (for example, plates for cable channels or trays on which people can walk) at a height of at least values, given in table. 4.2.2 for size G (Fig. 4.2.4). Unshielded live parts connecting the capacitor of high-frequency communication devices, telemechanics and protection with a filter must be located at a height of at least 2.5. In this case, it is recommended to install the filter at a height that allows repair (adjustment) of the filter without removing the voltage from the connection equipment. Transformers and devices in which the lower edge of the porcelain insulators is located above the level of the planning or the level of the structure (plates of cable channels or trays, etc.) at a height of at least 2.5 m are allowed not to be fenced (Fig. 4.2.4). At a lower height, the equipment must have a permanent fence that meets the requirements of 4.2.26 and located at a distance not less than that given in 4.2.57 from transformers and apparatus. Rice. 4.2.4. The smallest distances from unshielded live parts and from the bottom edge of the porcelain insulators to the ground

4.2.81 . Indoor switchgears and substations can be located both in detached buildings and be built-in or attached. The addition of a substation to an existing building using a building wall as a substation wall is allowed, provided that special measures are taken to prevent a violation of the waterproofing of the joint during the draft of the attached substation. The specified settlement must also be taken into account when attaching the equipment to the existing wall of the building.

For additional requirements for the construction of built-in and attached substations in residential and public buildings, see Ch. 7.1.

4.2.82 . In the premises of 35-220 kV indoor switchgears and in closed transformer chambers, stationary devices or the possibility of using mobile or inventory lifting devices should be provided for the mechanization of repair work and equipment maintenance.

In rooms with switchgear, a site for repair and adjustment of withdrawable elements should be provided. The repair site should be equipped with means for testing the circuit breaker drives and control systems.

4.2.83 . Closed switchgears of different voltage classes, as a rule, should be placed in separate rooms. This requirement does not apply to KTP 35 kV and below, as well as to GIS.

It is allowed to place switchgear up to 1 kV in the same room with switchgear above 1 kV, provided that parts of switchgear or substation up to 1 kV and above will be operated by one organization.

4.2.84 . When assembling the switchgear in the indoor switchgear, service platforms at different levels should be provided if they are not supplied by the manufacturer.

4.2.85 . Transformer rooms and closed switchgear are not allowed to place:

1) under the premises of production facilities with a wet technological process, under showers, bathrooms, etc .;

2) directly above and below the premises, in which more than 50 people can be at the same time within the area occupied by the switchgear or transformer rooms. for a period of more than 1 hour. This requirement does not apply to transformer rooms with dry or non-combustible transformers, as well as switchgear for industrial enterprises.

4.2.86 . The clear distances between non-insulated live parts of different phases, from non-insulated live parts to earthed structures and fences, floor and ground, as well as between non-shielded live parts of different circuits, should be at least the values ​​given in table. (fig. 4.2.14 - 4.2.17).

Flexible buses in indoor switchgear should be checked for their convergence under the action of short-circuit currents in accordance with the requirements.

4.2.88 . Non-insulated live parts must be protected from accidental contact (placed in chambers, fenced off with nets, etc.).

When placing non-insulated live parts outside the chambers and placing them below the size D according to table. they must be fenced from the floor. The height of the passage under the fence must be at least 1.9 m (Fig. 4.2.17).

Live parts located above the fences up to a height of 2.3 m from the floor must be located in the plane of the fence at the distances given in table. for size "B" (see fig. 4.2.16).

Apparatus in which the lower edge of the porcelain (polymer material) of the insulators is located above the floor level at a height of 2.2 m or more may not be fenced if the above requirements are met.

The use of barriers in fenced cells is not allowed.

4.2.89 . Unshielded uninsulated leading parts of various circuits located at a height exceeding the "D" dimension according to the table. 4.2.7 should be located at such a distance from one another so that after disconnecting any circuit (for example, a bus section), its safe service is ensured in the presence of voltage in adjacent circuits. In particular, the distance between unenclosed live parts located on both sides of the service corridor must correspond to the size "G" according to table. (see fig. 4.2.16).

4.2.90 . The width of the service corridor should ensure convenient maintenance of the installation and the movement of equipment, and it should be at least (counting in the light between the fences): 1 m - with a one-sided arrangement of the equipment; 1.2 m - with double-sided equipment.

In the service corridor, where the switches or disconnector drives are located, the above dimensions should be increased, respectively, to 1.5 and 2 m.With a corridor length of up to 7 m, the corridor width can be reduced for two-way service to 1.8 m.

4.2.91 . The width of the service corridor for switchgear with withdrawable elements and KTP should ensure ease of control, moving and turning the equipment and its repair.

When installing switchgear and KTP in separate rooms, the width of the service corridor should be determined based on the following requirements:

for single-row installation - the length of the largest of the switchgear bogies (with all protruding parts) plus at least 0.6 m;

with a two-row installation - the length of the largest of the switchgear bogies (with all protruding parts) plus at least 0.8 m.

If there is a corridor on the back side of the switchgear and KTP for their inspection, its width should be at least 0.8 m; individual local narrowings are allowed no more than 0.2 m.

With an open installation of switchgear and transformer substations in industrial premises, the width of the free passage should be determined by the location of the production equipment, ensure the possibility of transporting the largest elements of the switchgear to the transformer substation, and in any case, it should be at least 1 m.

The height of the room must be at least the height of the switchgear, KTP, counting from busbar inputs, jumpers or protruding parts of the cabinets, plus 0.8 m to the ceiling or 0.3 m to the beams.

A lower height of the room is allowed if this ensures the convenience and safety of replacement, repair and adjustment of equipment for switchgear, KTP, bus bushings and jumpers.

4.2.92 . The calculated loads on the floors of the premises along the path of transportation of electrical equipment should be taken taking into account the mass of the heaviest equipment (for example, a transformer), and the openings should correspond to their dimensions.

4.2.93 . With air inputs to closed switchgear, KTP and closed substations that do not cross passages or places where traffic is possible, etc., the distance from the lowest point of the wire to the earth's surface should be at least the size "E" (Table and Fig. 4.2 .17).

At smaller distances from the wire to the ground, in the corresponding area under the input, either the area should be fenced with a 1.6 m high fence, or a horizontal fence under the input. In this case, the distance from the ground to the wire in the plane of the fence must be at least the size "E".

When air inputs cross passages or places where traffic is possible, etc., the distance from the lowest point of the wire to the ground should be taken in accordance with 2.5.212 and 2.5.213.

The distances between adjacent line terminals of two circuits must be at least the values ​​given in table. 4.2.3 for size "D", if no partitions are provided between the terminals of adjacent circuits.

On the roof of the indoor switchgear building in the event of an unorganized drainage over the air inlets, visors should be provided.

4.2.94 . Exits from the reactor plant should be performed based on the following requirements:

1) with a switchgear length up to 7 m, one exit is allowed;

2) if the length of the switchgear is more than 7 to 60 m, two exits at its ends must be provided; it is allowed to place exits from the switchgear at a distance of up to 7 m from its ends;

3) if the length of the switchgear is more than 60 m, in addition to exits at its ends, additional exits must be provided so that the distance from any point of the service corridor to the exit is no more than 30 m.

Exits can be made to the outside, to the staircase or to another production room of category "G" or "D", as well as to other compartments of the switchgear, separated from this by a fire door of II degree of fire resistance. In multi-storey switchgears, the second and additional exits can also be provided to a balcony with an external fire escape.

The gates of cells with a sash width of more than 1.5 m must have a wicket if they are used for the exit of personnel.

4.2.95 . It is recommended to make the floors of the switchgear premises over the entire area of ​​each floor at one level. The construction of the floors must exclude the possibility of the formation of cement dust. Thresholds in doors between separate rooms and in corridors are not allowed (for exceptions, see 4.2.100 and 4.2.103).

4.2.96 . The doors from the switchgear must open in the direction of other rooms or outward and have self-locking locks that can be opened without a key from the side of the switchgear.

Doors between compartments of one switchgear or between adjacent rooms of two switchgears must have a device that fixes the doors in the closed position and does not prevent the doors from opening in both directions.

Doors between rooms (compartments) of switchgear of different voltages must open towards switchgear with lower voltage.

Locks in the doors of premises of switchgear of the same voltage must be opened with the same key; keys from the entrance doors of the switchgear and other premises should not fit the camera locks, as well as the door locks in the fences of electrical equipment.

The requirement to use self-locking locks does not apply to switchgears of urban and rural distribution electrical networks with a voltage of 10 kV and below.

4.2.97 . The enclosing structures and partitions of the switchgear and KTP for auxiliary needs of the power plant should be made of non-combustible materials.

It is allowed to install switchgear and transformer substations for own needs in the technological rooms of substations and power plants in accordance with the requirements of 4.2.121.

4.2.98 . In one room of the switchgear with a voltage of 0.4 kV and above, it is allowed to install up to two oil transformers with a capacity of up to 0.63 MVA each, separated from each other and from the rest of the switchgear room by a partition made of non-combustible materials with a fire resistance limit of 45 minutes, at least the height of the transformer, including the high voltage bushings.

4.2.99 . Devices related to starting devices for electric motors, synchronous compensators, etc. (switches, starting reactors, transformers, etc.) may be installed in a common chamber without partitions between them.

4.2.100 . Voltage transformers, regardless of the mass of oil in them, are allowed to be installed in fenced RU chambers. In this case, a threshold or ramp must be provided in the chamber, designed to hold the full volume of oil contained in the voltage transformer.

4.2.101 . The switch compartments should be separated from the service corridor by solid or mesh fences, and from each other by solid partitions made of non-combustible materials. These switches must be separated from the drive by the same partitions or shields.

Under each oil switch with an oil mass of 60 kg or more in one pole, an oil receiver device for the full volume of oil in one pole is required.

4.2.102 . In closed, free-standing, attached and built-in substations, in the chambers of transformers and other oil-filled apparatus with an oil mass in one tank up to 600 kg when the chambers are located on the ground floor with doors going out, oil collecting devices are not performed.

If the mass of oil or non-combustible environmentally friendly dielectric in one tank is more than 600 kg, an oil receiver must be arranged, designed for the full volume of oil or for holding 20% ​​of the oil with a drain to the oil sump.

4.2.103 . When constructing chambers above the basement, on the second floor and above (see also 4.2.118), as well as when arranging an exit from the chambers into the corridor under transformers and other oil-filled apparatuses, oil receivers should be performed in one of the following ways:

1) with an oil mass in one tank (pole) up to 60 kg, a threshold or ramp is performed to hold the full volume of oil;

2) with an oil mass of 60 to 600 kg, an oil receiver is installed under the transformer (apparatus), designed for the full volume of oil, or at the exit from the chamber - a threshold or ramp to hold the full volume of oil;

3) with an oil mass of more than 600 kg:

oil receiver containing at least 20% of the total oil volume of the transformer or apparatus, with oil drainage into the oil sump. The oil drain pipes from the oil receivers under the transformers must have a diameter of at least 10 cm. On the side of the oil receivers, the oil drain pipes must be protected with nets. The bottom of the oil receiver should have a slope of 2% towards the sump;

oil receiver without oil drainage into the oil sump. In this case, the oil receiver should be covered with a grating with a 25 cm layer of clean washed granite (or other non-porous rock) gravel or crushed stone with a fraction of 30 to 70 mm and should be designed for the full volume of oil; the oil level should be 5 cm below the grate. The top level of gravel in the TV receiver under the transformer should be 7.5 cm below the opening of the air inlet ventilation duct. The area of ​​the oil receiver should be larger than the area of ​​the base of the transformer or apparatus.