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Which section can lie used for bus bar ?
Bars
Rods
Tubes
Any of the above
Any of the above
Bus bars in electrical sub-stations serve as a common junction point for multiple circuits. Because they must carry high currents with minimal voltage drop and heat, they are designed using various cross-sectional shapes like flat bars, solid rods, or hollow tubes depending on the current rating and voltage levels.
Bus bars in electrical sub-stations serve as a common junction point for multiple circuits. Because they must carry high currents with minimal voltage drop and heat, they are designed using various cross-sectional shapes like flat bars, solid rods, or hollow tubes depending on the current rating and voltage levels.
RacтАЛ>RdcтАЛ тАФ representing the increase in resistance due to the skin effect in solid conductors
I=JтЛЕA тАФ where I is current, J is current density, and A is the cross-sectional area
The choice of cross-section is determined by the skin effect and the mechanical strength required. At higher currents and voltages, hollow tubes are preferred to minimize the skin effect and increase the surface-to-volume ratio, which improves cooling, whereas solid bars or rods are sufficient for low to medium power installations.
Flat bars are common for low voltage and indoor switchgear.
Hollow tubes are ideal for EHV (Extra High Voltage) outdoor switchyards to reduce corona loss.
Bus bars must be mechanically rigid to withstand electrodynamic forces during short-circuit conditions.
Materials used are generally high-conductivity copper or aluminum alloys.
Flexibility in installation layout
High current carrying capacity per unit volume
Ease of maintenance and component connection
Requires high structural support at high currents
Potential for thermal expansion stress at joints
Power Distribution Substations
Switchgear Panels
Industrial Power Plants
For outdoor EHV substations, rigid tubular bus bars are standard due to their better corona performance.
Flexible bus bars (often multi-strand) are sometimes used in specific earthquake-prone regions to allow mechanical movement.
D is correct тАФ Bus bars can be fabricated from various cross-sectional shapes including flat bars, solid rods, and tubes depending on the application requirements like current magnitude, cooling needs, and corona prevention.
Always remember that for EHV (Extra High Voltage) transmission, the 'hollow tube' geometry is preferred specifically to combat corona loss, which is a common examiner trap.