18 Difference Between AC and DC Transmission Systems | HVAC vs HVDC

The generating electrical power transmits through the transmission and distribution system to the consumer.

Both transmission and distribution systems can be transmitted either by the alternating current (AC) or direct current (DC).

Under the power transmission construction, there are the four types of system classified.

• AC transmission system
• DC transmission system
• AC distribution system
• DC distribution system

Each system has different specifications like uses, functions, advantages, and disadvantages.

Here, in this article, we are going to study what is the difference between AC and DC transmission.

Let’s compare all the basic AC and DC transmission Concepts,

AC vs DC Transmissions | HVAC vs HVDC

#	Content	AC Transmission	DC Transmission
01	[Defination] What is the ac and dc transmission?	The transmission system which transmits alternating current is called an ‘AC transmission’.	The transmission system which transmits direct current is called a ‘DC transmission’.
02	Construction of AC & DC Transmission	The construction of AC transmission lines is more complicated.	The construction of DC transmission lines is less complicated.
03	Electric power	In this transmission, electric power can easily generate at high voltage.	In this transmission, electric power cannot easily generate at high voltage because of commutation problems.
04	Conductor	For the high voltage AC (HVAC) transmission, three conductors (i.e. Red, Yellow, and Blue phases) are used.	For the high voltage DC (HVDC) transmission, only two conductors (positive and negative) are used.
05	Insulation	It requires more insulation due to more conductors.	It requires less insulation due to less conductors.
06	Voltage Regulation	The AC transmission can easily increase and decrease the voltage level by using a step-up and step-down transformer.	The DC transmission can increase and decrease the voltage level by using the chopper and booster.
07	Required Factors	For the AC transmission lines, capacitance, inductance, and phase displacement need.	For the DC transmission lines, capacitance, inductance, and phase displacement do not need.
08	Transformer	The transformer is used to regulate the voltage level.	The transformer does not use.
09	Capacitance effect	Due to the presence of capacitance in AC transmission lines, a continuous power loss occurs.	Due to the absence of capacitance in DC transmission lines, less power loss occurs.
10	Inductance effect	The voltage drop is more due to the presence of inductance. So, it does not provide good voltage regulation.	The voltage drop is less due to the absence of inductance. So, it provides good voltage regulation.
11	Skin effect of AC & DC transmission	Skin effect occurs in the AC transmission system.	Skin effect does not occur in the DC transmission system.
12	Corona effect of AC & DC transmission	Corona losses mostly exist in the AC system.	Corona losses rarely exist in the HVDC system.
13	Effects of transmission	Stability and surge effects find in AC transmission.	The DC transmission is free from the stability and surge effects.
14	Required parts	It does not require a rectifier and inverter.	It requires a rectifier and inverter.
15	Installation Cost	Under construction and maintenance, the AC transmission system is cheap.	Under construction and maintenance, the DC transmission system is expensive.
16	Distance over power transmission	For short-distance power transmission, the AC transmission system is mostly preferred.	For large-distance power transmission, the DC transmission system is mostly preferred.
17	Maintenance	Maintenance of this system is easy through connected substations.	Maintenance of this system is difficult as compared to the AC system.
18	Repairing	Repairing of AC transmission is very simple over DC transmission.	Repairing of DC transmission is not simple over AC transmission

I have covered all the basic comparisons of AC and DC transmission. Also, describe the main advantage of the AC over the DC transmission systems and the disadvantages of an HVDC over HVAC.

If you have any queries regarding to the AC Vs DC transmission line, you can ask through the below comment.

Read related some differences:

• Alternating current vs Direct current
• Conductor vs Insulator
• Capacitance vs Inductance
• Underground cable vs Overhead line
• Core transformer vs Shell transformer
• Active power vs Reactive power
• Single phase system vs Three-phase system
• Star connection vs Delta connection

Thanks for Reading!