What is the Advantages and Disadvantages of D.C. and A.C. Transmission System?

What is the Advantages and Disadvantages of D.C. (Direct Current) and A.C. (Alternating Current) Transmission System?

The electrical energy transmission can be transmitted either by means of DC- Direct Current or AC- Alternating Current each system has its own advantages and disadvantages. From that point of view, we want to discuss today the technical advantages and disadvantages of the two electrical energy transmission systems for of electric power network.

D.C. Energy Transmission System

From the couple of years past, engineers in transmission sector are rethinking the DC electric transmission system. DC electric power transmission has been receiving the active consideration due to its numerous advantages as bellow:

Advantages of DC Electrical Energy Transmission System.

The high voltage DC energy transmission has the following advantages over the high voltage AC energy transmission system.

(i) DC system requires only two conductors comparing to three for AC transmission;

(ii) In DC transmission system there is no presence of inductance, capacitance, phase displacement and surge problems comparing AC transmission system;

(iii) In DC electric transmission line has better voltage regulation comparing AC system due to the absence of inductance. For a particular same load the voltage drop in a DC transmission line is less than the AC;

(iv) The total conductor cross section of the transmission line is utilized due to their no skin effect in a DC system;

(v) For the same working voltage, the potential stress on the insulation is less in case of DC system than that in AC system. So, a DC line requires less insulation;

(vi) There in a DC line has less corona loss and reduced interference with communication circuits;

(vii) The high voltage DC transmission is free from the dielectric losses, particularly in the case of cables;

(viii) In DC transmission system, there are no stability problems and synchronizing difficulties comparing AC system.

You may read the another article to know details about D.C. transmission and distribution:

HVDC Transmission and Distribution System Network

Disadvantages of DC Electrical Energy Transmission System

The high voltage DC energy transmission has the following dis advantages over the high voltage AC energy transmission system.

(i) Due to commutation problems the electric power cannot be generated at high DC voltage that is one of the disadvantage of DC system;

(ii) Stepped up or stepped down in electric energy transmission system is an important factor, but in the DC voltage cannot be stepped up for transmission of power at high voltages;

(iii) The DC switches and circuit breakers have their own limitations.

A.C. Energy Transmission System

Now-a-days, most of electrical energy transmission system is in Alternating Current or AC system. Exclusively generation, transmission and distribution system is popular in all over the world.

Advantages of AC Electrical Energy Transmission System

(i) It is easy and can be generated at high voltages AC electric power system;

(ii) The maintenance of AC sub-stations is easy and cheaper than DC transmission system;

(iii) The AC voltage can be stepped up or stepped down by transformers with ease and efficiency that is not possible in DC energy transmission system. This permits to transmit power at high voltages and distribute it at safe potentials in AC electric transmission system.

Disadvantages of AC Electrical Energy Transmission System

(i) An AC transmission conductor copper is required more copper than a DC transmission line;

(ii) The construction of AC transmission electric line network is more complicated than a DC transmission electric line network;

(iii) Due to skin effect in the AC system, the effective resistance of the line is increased;

(iv) The AC line system has capacitance. Therefore, there is a continuous loss of power due to charging current even when the line is open.