1. EE-504.24 1
OBJECTIVES
• Advantages of HVDC transmission systems.
• Disadvantages of HVDC Transmission System.
• Applications of HVDC transmission systems.
2. EE-504.24 2
•The main advantages of HVDC transmission
system
Advantages of HVDC Transmission system
• Simple in line construction
•Ground can be used as return conductor.
•No charging current.
•Less corona and radio interference.
•No skin effect.
•Bulk power can be transmitted over long distances.
•Synchronous operation is not required.
•Tie-line power can be easily controlled.
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The main advantages of HVDC transmission system
•Power transmission can be also possible between
unsynchronized AC distribution systems(Interconnection
of A.C systems of different frequencies).
•Cables can be worked at high voltage gradient.
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• It is very difficult to break the D.C currents hence it
requires high cost of D.C circuit breakers.
• Not possible to use transformers to change the voltage
levels.
• Cost of conversion equipment is very expensive.
• Due to the generation of harmonics in converters it
requires AC& DC filters, hence the cost of converting
station is increased.
• Complexity of control.
• Converters have little over load capability.
Disadvantages of HVDC Transmission system
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Applications of HVDC Transmission Systems
•Long distance bulk power transmission by overhead lines.
Interconnection of AC systems operating at different
frequencies.
Back-to-Back HVDC coupling stations.
MTDC asynchronous interconnection between 3 or more AC
network.
Control & stabilization of power flows in AC interconnection
of large interconnected systems.
