Busbar

Typology and appointment

The busline is the device from bare or insulated conductors, insulators and constructions which serve for transfer and electric power distribution in production premises, in territories of industrial enterprises, struts of apartment houses, trade premises and so forth. According to GOST 28668.1-91 (an IEC 439-2-87), the busline — the complete device in the form of the system of conductors which is consisting of the buses separated by intervals and relying on the isolating material, placed in a pipe, a tray or other similar cover, passed standard tests.

Elements can be a part of the busline:

• direct sections of standard length (2 m, 3 m, 4 m),
• sections for distribution,
• blocks for connection of sections,
• elements of connection to boards and transformers,
• special purpose sections
  • transpositions of phases,
  • compensatory,
  • flexible,
  • by-pass blocks for installation of time cut-outs and other switching equipment.

To destination buslines subdivide into trunk, distribution, lighting and trolley.

• Trunk buslines - are intended for a construction of trunk lines, communication of substations on the party of low tension, for a power supply of distribution buslines, distribution points, separate large electroreceivers up to 1000 V with a frequency of 50 Hz. Buslines are the complete electric network consisting of constructions for fastening and the separate sections connected among themselves by the provided method. They are made by separate sections of the normalized length — direct and figured (angular and the dividing) that allows to assemble the busline of any configuration. Face values of trunk buslines are from 630A to 6300A.
• Distribution buslines – consist of special sections for distribution with the installed by-pass blocks, directly which power consumers will join. Face values of distribution buslines - from 100A to 6300A.
• Lighting buslines apply to creation of networks of lighting and connection of lighting instruments and also consumers of small power. Lighting buslines make on currents from 25 to 40 And.

Trolley buslines apply to a power supply of shop electroreceivers of the rolling stock (for example, cranes, frame cranes, monorail roads, floor carts, installations for cutting of fabrics) and produce from 35 A to 1 kA on currents.

Feed box of a power supply, (2016)

Construction features

Construction of the majority of buslines represents a packet of the buses which are densely pressed to each other, isolated by means of a polyester film and placed in a casing. Buses are manufactured of copper or squared aluminum. The casing, depending on the producer, can be aluminum or steel.

Сечение шинопровода Canalis KT от Schneider Electric, (2016)

By means of such construction of the busline uniform distribution of current density on the section of the conductor, unlike a cable is provided. This feature leads to reduction of voltage drop and losses of energy in the trunk. Calculations show that at use of the busline on current 2000A 100 m long instead of a cable line of the same length on similar loading it is possible to save 1,936,110 rub a year only on losses which arise in the line at electric power transmission.

Example: As an example the electric power transmission line by L=100m length, U=400B tension, a current capacity of I=2000A is offered at cosϕ=0.9, °C t=35 ambient temperature.

Solution:

Voltage drop in ShP KTA2000 Per execution (table value of p. 144 of the directory of 2016):

DUT = 0.003 (M B/100 / A);

Voltage drop in ShP at a distributed load:

Dushp = DUT·L·I = (0.003·100 · 2000)/100 = 6 B.

Voltage drop in cable lines VVGNG-FRLS 5х240-1:

Dukl = (P· R·L+Q·X·L)/U = 33 V, where

P and Q – respectively - active and reactive capacities, R and X - respectively - active and reactive resistance of a cable.

The delta in voltage drops between a cable and the busline will make:

Dukabel – Dushinoprovod = 33 – 6 = 27 V

Equivalent power losses provided that the line works within 10 hours a day will make:

Drsut = 3·I·DU·cosϕ\• 10 = 3·2000 · 27•0,9 · 10 = 1458 kW/hour

1 kW of the electric power at an odnostavochny rate for the enterprises is equal to 5.03 rub/kWh. Therefore additional costs on payment of losses which will arise in case of installation of cable passages in relation to routes of buslines in a month provided that the enterprise works 22 days in a month will make:

Dsdop.z. month =22·Drsut·5.03 = 22·1458 · 5.03=161,340 rub

Additional costs in a year:

Dsdop.z. year =12 • Dsdop.z. month of =12•161340=1 936 110 rub

Compact, reliable and safe

In addition to technical and economic indicators there is some other technical properties of the busline. For example, simplicity of planning and design of routes. All routes of buslines can be drawn at a design stage in 3D - a type that the graph of network and arrangement of possible installation of by-pass blocks for a power supply of consumers allows to estimate accurately. Some producers of buslines offer the special software, for example, of CanBrass or Brass II from Schneider Electric company which allow to draw routes of buslines in DWG expansion in a 3D view with the subsequent possibility of loading of routes in drawings of projects.

As buslines are delivered in the form of separate sections of final length and a clear form, installation represents consecutive collecting of modules: as assembly of the designer, according to the accurate and clear instruction. It can save up to 70% of working time in comparison with installation of the similar route of a cable system. Connection of consumers to the available bus is expedited by means of connection modules. Installation on any load-carrying structures is possible.

Sizes

The route of the busline will always take less places in comparison with cable passages, irrespective of face value.

Mass-dimensional parameters of routes, (2016)

The flexibility of transformation of a system should be considered at a distributed load when the power of consumers often changes or they are physically moved. A possibility of output coupling in different points of network without interruption in power supply - advantage of buslines.

Possibility of reusable use. The route of the busline can be dismantled and mounted then to remain suitable for use unlimited number of such iterations provided that installation dismantling were carried out without violations.

A Shinoprovodny system is safer and reliable in comparison with cable passages by parameters:

• shielding characteristics of a casing of the busline provide the low level of electromagnetic radiation. It allows to lay the route of the busline in close proximity to data networks or installation sites of the radio-electronic equipment;
• standard execution of the busline corresponds to degree of protection of IP55 and mechanical durability of IK08. Construction of the busline prevents water ingress from sprinklers of systems and also high degree of protection of a casing against blows and vibration resistance;
• all elements of the busline do not contain halogens and PVC. At the fire the busline does not select smoke and toxic gases and itself serves as an antifiery barrier, prevents distribution of fire within 2 hours when using additional fireproof barriers;
• devices of blocking exclude mounting errors, installation and removal of the by-pass block energized. Degree of protection against touch to current carrying parts of an electric unit of IP ** provides D absolutely safe working conditions for service staff owing to lack of access to current carrying parts;
• specially developed construction of the busline, accession nodes on the feeding party, the party of the consumer, abutting monoblock connections, the dividing modules. Observance of efforts of tightening and provision of nodes at installation guarantee reliability of transfer and electric power distribution;
• due to dense laying of insulated conductors without air gap and their contact with each other and with the body which acts as a cooling radiator easy heat extraction, the current selected at course is provided.
• at normal operation buslines practically do not need service during all service life - 25-30 years.

Links

1. Bible by the electrician: PUE, MPOT, PTE. — M.: Eksmo, 2012. — 752 pages — (The Russian legislation. Technical literature).
2. GOST 28668.1-91 (IEC 439-2-87) Low-voltage complete devices of distribution and management.
3. Technical Schneider Electric collection, Release No. 29.