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
What are the advantages of dc transmission system over ac transmission system ?
DC system is economical
There is no skin effect in DC system
Corona limits are highest for DC circuits as compared to AC circuits
All of the above
All of the above
DC transmission systems offer significant technical and economic advantages over AC systems, particularly for long-distance and bulk power delivery. These advantages include higher power transfer capacity for the same insulation levels, reduced losses, and the elimination of reactive power constraints.
DC transmission systems offer significant technical and economic advantages over AC systems, particularly for long-distance and bulk power delivery. These advantages include higher power transfer capacity for the same insulation levels, reduced losses, and the elimination of reactive power constraints.
PDCтАЛ=VdтАЛIdтАЛ тАФ Power transmission in DC
IrmsтАЛ=ImaxтАЛsin(╧Йt) тАФ AC current variation showing RMS limitation
In DC systems, there is no skin effect as the current distribution is uniform across the conductor cross-section, allowing full utilization of material. Corona discharge is minimized compared to AC because DC does not experience the oscillating voltage peaks that ionize surrounding air as rapidly as high-frequency AC, allowing for higher voltage gradients.
No skin effect means lower resistance for AC cables compared to DC wires of equivalent cross-section.
DC transmission is ideal for interconnecting grids of different frequencies.
HVDC lines require fewer conductors than 3-phase AC lines for the same power rating.
No charging current issues in HVDC, making it superior for long sub-marine cables.
Higher power per conductor
No reactive power compensation required
Smaller tower sizes and narrower right-of-way
Improved system stability
High cost of converter stations
Difficulty in circuit breaking due to lack of natural zero crossing
Generation of harmonics requiring expensive filters
Long-distance bulk power transmission
Undersea cable transmission
Asynchronous interconnection of power grids
| Feature | AC | DC |
|---|---|---|
Skin Effect | Significant | Negligible/None |
Corona Loss | Higher | Lower |
Corona is a function of voltage and frequency; since DC frequency is zero, corona inception voltage is higher.
Skin effect increases AC resistance (RACтАЛ>RDCтАЛ), leading to higher ohmic losses.
D is correct тАФ All listed options are technically accurate advantages of DC transmission over AC.
Always remember that while HVDC is superior for long distances, the prohibitive cost of converter stations keeps AC as the dominant choice for distribution networks.