Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
In step up substation the electrical power is transmitted by
phase, 3-wire system
phase, 4-wire system
phase, 3-wire system
phase with mid point earthed system
phase, 3-wire system
In step-up substations used for long-distance power transmission, a 3-phase, 3-wire system is preferred. This configuration eliminates the need for a neutral conductor, as the system is inherently balanced, leading to significant material savings in overhead lines.
In step-up substations used for long-distance power transmission, a 3-phase, 3-wire system is preferred. This configuration eliminates the need for a neutral conductor, as the system is inherently balanced, leading to significant material savings in overhead lines.
P=3тАЛVLтАЛILтАЛcos╧Х тАФ total power in a 3-phase system
INтАЛ=IRтАЛ+IYтАЛ+IBтАЛ=0 тАФ balance condition for 3-wire system
The 3-phase, 3-wire system transmits power using three conductors, each carrying a phase shifted by 120┬░. Since the sum of currents in a balanced 3-phase system is zero (IRтАЛ+IYтАЛ+IBтАЛ=0), no return path (neutral) is required for the load current. This allows for higher efficiency and lower installation costs over long transmission distances.
Transmission lines are usually operated at high voltages to reduce transmission losses (I2R).
3-phase 3-wire systems minimize copper usage by eliminating the neutral wire.
Balanced loading ensures the neutral current remains zero in a Wye (Star) connection.
Step-up substations typically use Delta-Star or Star-Star transformer configurations depending on grounding requirements.
Significant reduction in conductor material cost.
Higher efficiency due to reduced total line impedance.
Ideal for long-distance bulk power transfer.
Not suitable for single-phase consumer loads without additional transformation.
Requires balancing of loads to prevent neutral shifts.
High Voltage Transmission Lines
EHV (Extra High Voltage) Substations
A 3-phase, 4-wire system includes a neutral conductor and is primarily used for secondary distribution to provide both 3-phase and single-phase (line-to-neutral) power.
Option D is used in specific grounding configurations, not for primary bulk power transmission.
A is correct тАФ Transmission systems use a 3-phase, 3-wire arrangement to transport bulk electrical power efficiently without the need for a neutral conductor.
Always remember that for transmission (bulk power), the primary goal is efficiency and economy; thus, the neutral wire is omitted to save conductor costs.