Design of industrial supplies, power supply, Lighting systems. Design stage of machined wire. - Extra Know

Design of industrial supplies, power supply, Lighting systems. Design stage of machined wire.

Design of industrial supplies, power supply, Lighting systems. Design stage of machined wire.

The overhead powerline is still very famous. Many cities have adopted new standards, but the cost of designing and installing the subway however is much lower, so there will be demand for a long period of time.

The installation of the machined wires is a challenge that only qualified professionals can successfully complete. You need extensive experience and expertise at every stage from design to installation.

The construction of such structures always requires several steps.


    Gather information about where the installation will be done. The entire complex of geology and other engineering work is performed to determine all the main characteristics of topography.

    The soil features determine the level of complexity of the transmission line installation.
    Features of terrain. High altitude differences rarely occur, but if present, it becomes much more difficult to design.
    Local temperature conditions. Both annual and peak temperatures are being studied carefully. It is important to determine the correct cable and tension level.
    Wind blast. Where hurricanes are frequent, additional measures are needed to ensure the safety of power lines.
    Thunderstorm activity. Frequent thunderstorms can damage power lines and wires. Lightning protection is required in all cases, but there may be some intensity in other areas.

In the next step, the necessary drawings are created, in which the tower number of power lines, the installation features of each installation, and all other parameters are calculated. When you install an extended transmission line, it can take a long time to write a project document. In this case, you should contact the company that can reduce the temporary loss.
Coordination of project documents with competent authorities authorized to issue building permits.
Acquisition of required permission.

After that, the design is considered completed and the actual installation proceeds. However, the engineer's services at all stages of constructing the transmission line, if necessary, will monitor the facilities under construction and document the project.

Choosing Cable Material and Support as well as Cable Thickness and Tension The challenges The most important parameters to consider here in designing and installing power cables are:
The previous two points are very important when choosing the cable tension level. Tension levels should be calculated taking into account natural stretching and compression ratios at various temperature conditions (therefore, areas with large annual temperature amplitudes, power line design and construction are particularly difficult). Amplitude of cable deviation in strong winds. If the design here is somewhat inaccurate, you need to repair the power line for tens of kilometers and supply power to many objects in other weather disasters. Therefore, the expertise of engineers and designers can greatly reduce future maintenance.

All of these factors alone can be used to design power lines in a way that is reliable and does not make it difficult to operate in weather conditions.

Introduce

Wire and ground wire. General Information

Wires and cables construction

Calculated climatic conditions. It is full of wind and ice. Temperature effect

Critical period of power line. Critical temperature

Calculate the critical temperature of the span

literature

Introduce

Overhead power lines transmit and distribute electricity through wires located in the atmosphere and are fixed in pole insulators and line fittings and, in some cases, in brackets or engineering structure racks (bridges, chimneys, buildings, etc.).

Over 25,000 km of power lines with voltages greater than 35 kV and low voltage over 200,000 km. The purpose of constructing the line with a voltage of 220kV or more is by the integration of the power system, the installed power reserve jointly, the construction of the power plant lower voltage line is connected to the new consumer network including the rural. The power supply of rural settlements in state networks is much more reliable and economical than in small regional power plants.

There is no mechanization of construction and installation work, and it is impossible to perform operations without using the typical structures of support and foundation. Therefore, typical structures of supports and bases are used when constructing most current lines, and individual structures are only used in rare cases.

Special rules and standards for powerline design and construction have been developed. The basic requirements for transmission lines are determined by the current electrical installation regulations (electrical equipment rules), and according to this regulation the lines are divided into two categories according to voltage: up to 1000V and 1000V. And Rules - SNiP.

The following standard stresses are allowed - voltages above 3, 6, 10, 15, 20, 35, 110, 220, 330, 500 and 750 kV are standardized above 3-phase currents of 1000 W (1 kV) A power line is also configured with a three-phase current line. direct current.

The distance between the wire and the grounded part, from the wire to the ground, between the wire and the grounded part shall be such that the possibility of discharging between the wires at the operating voltage of the wire is excluded. c. Connect wires and ground structures and objects on supports. For this purpose, it is necessary to secure a sufficient dielectric strength of the insulator and the air insulation gap. Insulators and air gaps are also more likely to eliminate electrical discharge from overvoltages that can occur on lines of a given voltage.

The main element is the wires. Additional elements required for some lines to ensure reliability of insulators, line fittings, supports, and foundations are ground wires, grounding, lightning arresters, and so on.

Steel Aluminum, aluminum, aluminum, copper, bronze, steel bronze, and steel wires can be suspended from power lines. Currently, iron-aluminum wires are used in most cases with lines with voltages above 1000V. Aluminum wires often have voltages up to 35 kV and sometimes 110 kV lines. The steel wire is used not only for lines up to 1000V but also for rural lines up to 36kV. Copper, bronze and steel bronze wires are not actually used because of the lack of copper.

In a line with a voltage above 110kV, on the crown associated with the ionization of the air near the power wire. These losses decrease as the wire diameter increases. Thus, for 110kV lines, wires with diameters of 150kV - at least 15.2mm and 220kV - at least 11.4mm for a line of at least 21.6mm shall be used.

In order to limit crown losses to acceptable values, wires with very large diameters must be suspended on lines with voltages above 330kV. The crown loss can be reduced by replacing one wire with several parallel wires that form the so-called split phase. The phase division of two wires on a 500kV line to three wires and a line of 750kV on a 330kV line is usually applied with four or five wires.

Lightning cables are, in principle, twisted steel ropes on several wires. Sometimes a steel aluminum lightning protection cable hangs.

Insulators that break the wires in the overhead line are divided into pins and suspensions.

Pin insulators used in lines with voltages up to 35 kV are mounted on a support with the aid of a hook or pin. Wires are secured to this type of insulation with the help of wire binding. Both the pin and the suspension insulator are used in a line with a voltage of 35kV. Line-paused insulator with voltage greater than 110kV.

Suspended insulators consist not only of insulators and line fittings, but also ceramics or glass insulated parts and metal parts, which serve to connect several insulators together. A series of insulators connected in series is called a wreath. The wires are fixed to the wreath with line fittings - clamps and special parts. Fixing the wreaths to the supports is done with the help of coupling fittings.

Air lines are built in areas with varying climatic conditions that affect the choice of line elements. Guidance on the selection of expected climatic conditions for which the calculated loads are determined is given in the EMP.

The main climatic factors that determine load are wind and ice. Long-term observations allowed us to set boundaries between wind and ice covered areas with different wind speeds and intensity of ice formation. When designing power lines, wind and ice areas are determined by maps or, if necessary, updated observations.

At least three wires constituting one circuit are suspended on the three-phase AC overhead line, and at least two wires are installed on the DC transmission line.

Depending on the number of chains, transmission lines are divided into single circuit, dual circuit and multiple circuit. The number of circuits is determined by the power supply circuit, depending on the transmission power, the voltage of the transmission line and the need for redundancy. If the power supply requires two chains, these chains can be suspended in two separate single lines with single chain supports or a single dual line with dual shifts.

In principle, one double-circuit line is cheaper than two parallel single-chain lines and can be configured for a shorter period.

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