Overhead power lines with voltage above 1 kV. Application area. Definitions

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 2. Sewerage of electricity

Overhead power lines with voltage above 1 kV. Application area. Definitions

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

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2.5.1. This chapter of the Rules applies to overhead power lines with voltages above 1 kV and up to 750 kV, performed by bare wires (VL), and voltages above 1 kV and up to 20 kV, performed by wires with a protective insulating sheath - protected wires (VLZ).

The requirements for overhead lines with bare wires also apply to overhead lines of the appropriate voltage, performed by wires with a protective insulating sheath, in addition to the requirements specifically stipulated in these Rules.

This chapter does not apply to electric overhead lines, the construction of which is determined by special rules, norms and regulations (contact networks of electrified railways, trams, trolleybuses; overhead lines for power supply of signaling, centralization and blocking (SCB); overhead lines with a voltage of 6-35 kV, mounted on contact network supports, etc.).

Cable inserts in overhead lines must be made in accordance with the requirements given in 2.5.124 and Ch. 2.3.

2.5.2. Overhead power line above 1 kV - a device for transmitting electricity through wires located in the open air and attached with the help of insulating structures and fittings to supports, load-bearing structures, brackets and racks on engineering structures (bridges, overpasses, etc.).

For the beginning and end of the overhead line (VLZ) are accepted:

for ZRU - the place where the wire exits the hardware clamp connected to the bushing insulator;
for outdoor switchgear with linear portals - the place where the wire exits the clamp of the tension garland of insulators on the linear portal towards the overhead line;
at KTP - the place of fastening of the wire to the insulator of the KTP or the place where the wire exits the hardware clamp;
for transformer substations with a remote disconnector - the place where the wire exits the hardware clamp connected to the disconnector.

2.5.3. Overhead line span - a section of overhead lines between two supports or structures replacing supports.

The span length is the horizontal projection of this section of the overhead line.

Overall span lgab - span, the length of which is determined by the normalized vertical distance from the wires to the ground when the supports are installed on a perfectly flat surface.

Wind span lwind - the length of the overhead line section, from which the wind pressure on the wires and lightning protection cables * is perceived by the support.

Weight span lweight - the length of the overhead line section, the weight of the wires (cables) of which is perceived by the support.

Wire sag f is the vertical distance from the straight line connecting the wire attachment points to the wire.

Overall wire sag fgab - the largest wire sag in the overall span.

Anchor span - a section of overhead lines between two nearest anchor supports.

Suspension insulator - an insulator designed for movable fastening of current-carrying elements to supports, load-bearing structures and various elements of engineering structures.

A garland of insulators is a device consisting of several suspension insulators and linear fittings, movably connected to each other.

Cable fastening - a device for attaching lightning protection cables to a support; if the cable fastening includes one or more insulators, then it is called insulated.

Pin insulator - an insulator consisting of an insulating part fixed on a pin or hook of a support.

Reinforced fastening of a wire with a protective sheath - fastening of a wire on a pin insulator or to a garland of insulators, which prevents wires from slipping when a difference in tension occurs in adjacent spans in normal and emergency modes of the overhead line.

Dance of wires (cables) - stable periodic low-frequency (0,2-2 Hz) oscillations of a wire (cable) in a span with one-sided or asymmetric deposition of ice (wet snow, hoarfrost, mixture) caused by wind speed of 3-25 m/s and forming standing waves (sometimes in combination with traveling ones) with the number of half-waves from one to twenty and an amplitude of 0,3-5 m.

Vibration of wires (cables) - periodic vibrations of a wire (cable) in a span with a frequency of 3 to 150 Hz, occurring in a vertical plane with wind and forming standing waves with a swing (double amplitude) that can exceed the diameter of the wire (cable).

* Further cables.

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

normal mode - mode with unbroken wires, cables, garlands of insulators and cable fasteners;
emergency mode - mode when one or more wires or cables, garlands of insulators and cable fasteners are broken;
installation mode - mode in the conditions of installation of supports, wires and cables.

2.5.5. Populated area - lands of cities within the city limits within the boundaries of their prospective development for 10 years, resort and suburban areas, green areas around cities and other settlements, lands of urban-type settlements within the village limits and rural settlements within the limits of these points, as well as horticultural areas.

Hard-to-reach terrain - terrain inaccessible to transport and agricultural machines.

Uninhabited area - lands that are not classified as populated and hard-to-reach areas.

Built-up area - the territory of cities, towns, rural settlements within the boundaries of the actual building.

Overhead line route in cramped conditions - sections of the overhead line route passing through territories saturated with above-ground and (or) underground communications, structures, structures.

2.5.6. According to the conditions of wind impact on overhead lines, three types of terrain are distinguished:

A - open coasts of the seas, lakes, reservoirs, deserts, steppes, forest-steppes, tundra;
B - urban areas, forests and other areas evenly covered with obstacles with a height of at least 2/3 of the height of the supports;
C - urban areas with buildings over 25 m high, clearings in forests with trees higher than the height of supports, orographically protected winding and narrow sloping valleys and gorges.

An overhead line is considered to be located in a given type of area if this area is maintained on the windward side of the overhead line at a distance equal to thirty times the height of the support with a support height of up to 60 m and 2 km with a higher height.

2.5.7. Large crossings are crossings of navigable sections of rivers, canals, lakes and reservoirs, on which supports are installed with a height of 50 m or more, as well as crossings of gorges, ravines, water spaces and other obstacles with a crossing span of more than 700 m, regardless of the height of the overhead lines.

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

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