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
Why dont we prefer the HVDC link for the short distance transmission?
Huge Filters required
Audio Frequency Interferance
Complexity of Contol
Not economical
Not economical
HVDC transmission is not preferred for short distances because the high capital cost of converter stations (rectifiers and inverters) outweighs the savings in line construction costs. While HVDC lines are cheaper per kilometer, the initial 'break-even' distance must be crossed before total costs become lower than HVAC transmission.
HVDC transmission is not preferred for short distances because the high capital cost of converter stations (rectifiers and inverters) outweighs the savings in line construction costs. While HVDC lines are cheaper per kilometer, the initial 'break-even' distance must be crossed before total costs become lower than HVAC transmission.
CTotalтАЛ=CstationтАЛ+ClineтАЛтЛЕL тАФ Total cost of transmission where L is distance.
Break-even┬аdistance=CAClтАЛinecтАЛostтАЛтИТCDClтАЛinecтАЛostтАЛCHVDCsтАЛtationтАЛтИТCHVACsтАЛtationтАЛтАЛ
In HVAC, stations only require transformers, which are relatively inexpensive. HVDC systems require expensive power electronic converter stations at both ends to perform AC-DC and DC-AC conversion. The total cost function is represented as CTotalтАЛ=CConverterтАЛ+(CLineтАЛ├ЧLength). Since CConverterтАЛ is significantly high, CLineтАЛ savings only compensate for the converter investment at distances typically greater than 500-800 km.
HVDC converter stations are extremely expensive due to complex power electronic devices (Thyristors/IGBTs).
Line cost for DC is lower because it requires fewer conductors (usually two) and has lower insulation requirements.
Economic viability is determined by the intersection of the cost curves.
Shorter lines do not benefit from the reduced line material costs to offset the fixed converter costs.
Lower line construction cost (fewer conductors)
No skin effect
Easier to control active power flow
Asynchronous interconnection of grids
High cost of converter stations
Generation of harmonics
Limited overload capacity
Complex circuit breaking
Long-distance bulk power transmission
Undersea cable interconnections
Asynchronous grid synchronization
| Feature | HVDC | HVAC |
|---|---|---|
Converter Station Cost | Very High | Low (Transformer based) |
Transmission Line Cost | Low | High |
Option A: While filters are needed to suppress harmonics generated by converters, they are not the primary reason why HVDC is avoided at short distances.
Option B: Audio frequency interference is a technical challenge, but manageable with shielding and is not the economic driver for distance preference.
Option C: Control complexity is high, but modern microprocessors have made this a standard operational feature in modern grids.
D is correct тАФ The high initial investment cost of converter stations makes HVDC economically unviable for short transmission distances compared to traditional HVAC systems.
Always remember that in power systems, the choice between AC and DC transmission boils down to the trade-off between the high fixed cost of stations and the variable cost per unit length of the transmission line.