Answer: DC transmissions system has many advantages over AC transmission system some of these are discussed below
1. DC transmission system is cheaper in cost.
2. There is no skin effect in DC transmission system.
3. Less transmission losses
4. It has better voltage regulation.
5. DC transmission has greater reliability.
6. It is absence of charging current and limitations of cable length
7. It has no short circuit current.
8. It has less corona loss and radio interference.
9. It has higher operating voltage.
- Cost of transmission is less, since only two conductors are used for transmission.
- There is no reactive power. So transmission losses are reduced.
- Due to high voltage transmission, for the same power current is less. So I2R loss is very less.
- Because of DC transmission, there is no skin effect. So thin conductors can be used. In case of HVAC transmission, the thick conductors must be used to eliminate skin effect.
- Two AC systems having different frequencies can be interconnected using HVDC transmission lines. This is not possible in HVAC transmission system.