HVDC Advantages, Disadvantages Over HVAC Transmission System

In this short post let us see various advantages and disadvantages of HVDC transmission system over HVAC transmission system.

HVDC = High Voltage DC Transmission System
HVAC = High Voltage AC Transmission System
For bulk power transmission over long distances high voltage DC transmission lines are preferred. Because HVDC transmission system has the following advantages over high voltage AC transmission system.

HVDC Advantages:

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.
Installation cost is less. Due to only two conductors and smaller towers required for HVDC.
HVDC uses electronic converters. So Protections, fault clearance can be implemented faster than HVAC. Therefore DC transmission system have improved transient stability.
In case of faults, power levels on HVDC system can be controlled electronically (i.e., very fast).
Since HVDC requires no charging current and the reactive power, it is preferred in power transmission through cables.
Unlike HVDC transmission system, HVAC induces body currents in the vicinity of the conductors.
HVDC transmission does not have any dielectric loss heating problems in the insulation of conductors.
HVDC has minimum audible noise as well as minimum radio, TV interference.
Due to bipolar transmission the voltage levels are balanced with respect to an earth.
DC cables used for transmission are cheaper than AC cables.
In HVDC, line charging and electric resonance do not present which leads to high-efficiency.

Disadvantages of HVDC Transmission:

High cost converting and inverting equipments are required for HVDC transmission. So it is uneconomical for low power supply over short distances.
Converters control is quite complex.
Additional filters are required at various stages of HVDC transmission system. So its lead to high installation cost.

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The post HVDC Advantages, Disadvantages Over HVAC Transmission System appeared first on Power Electronics A to Z.

HVDC Advantages, Disadvantages Over HVAC Transmission System