A FEW WORDS ABOUT BUSBARS
Author: Radoje Jankovic
Busbars are groups of “conductors” in low and high voltage electrical plants from which individual consumers are supplied, whether they are within the plant itself or in a building. They are used for power voltage distribution. In low voltage plants, as a rule, 3 or 4 busbars are used, while in high voltage plants only 3 busbars are always used for three phases.
By construction, the busbars can be solid profile, laminated and stranded (rope).
The full profile, usually rectangular and circular in cross-section, is used for low-voltage and high-voltage indoor and outdoor installations.
Round busbars can also be tubular.
Terminal busbars are most commonly used in outdoor installations for almost all voltage levels from medium to highest voltage levels. These busbars are copper or Al / Che.
Laminated busbars are of more recent date and are used in low-voltage and medium-voltage cells of distribution plants, and can be insulated or uninsulated. I’ve talked about them before.
It should also be said that busbars of full profile but “complex” cross-section are used a lot, e.g. “U”, “L”, etc. Full profile busbars are mounted on supporting insulators made of porcelain or some artificial insulating mixture.
Low-voltage and high-voltage busbars can be painted with appropriate color-defined standards as shown in this figure. These colors are in accordance with DIN, VDE and IEC as well as our domestic standards. Of course, in some countries the colors of the buses are different (England, America…). I mention this for the reason that you are not awake when you see busbars painted outside the mentioned standards in some photos.
Colored buses can be loaded with higher current. Refer to the bus tables in one of the electrical manuals.
All busbars in all plants must be designed for all loads and forces that occur in the plant.
In the first photo from my colleague Berislav Pribanić, we see flat low-voltage painted busbars in one cell of the distribution plant.
In the second photo of me, you can see the pipe busbars at the 20 kV outdoor distribution plant.
In the third, my photo, you see the strand Al/Steel busbars in a 35 kV outdoor switchyard.
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