The generating electrical power transmits through the transmission and distribution system to the consumer.
Both transmission and distribution systems can be transmitted either by alternating current (AC) or direct current (DC).
Under the power transmission construction, there are four types of systems 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 cannot easily be generated at high voltage because of commutation problems. | 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. | In this transmission, electric power can easily be generated at high voltage. |
| 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 | Corona effect of AC & DC Transmission | Skin effect occurs in the AC transmission system. | Skin effect does not occur in the DC transmission system. |
| 12 | Stability and surge effects are found in AC transmission. | Corona losses mostly exist in the AC system. | Corona losses rarely exist in the HVDC system. |
| 13 | Effects of transmission | The transformer is not use. | 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 |
| 19 | Used | AC transmission lines are mostly preferred for long-distance power transmission, regional power distribution, industrial and commercial applications. | DC transmission lines are also utilized for long-distance power transmission, but they are more commonly employed in underwater and underground cables, HVDC links, and the integration of renewable energy systems. |
I have covered all the basic comparisons of AC and DC transmission. Also, describe the main advantages of AC over DC transmission systems and the disadvantages of 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!
I have completed master in Electrical Power System. I work and write technical tutorials on the PLC, MATLAB programming, and Electrical on DipsLab.com portal.
Sharing my knowledge on this blog makes me happy. And sometimes I delve in Python programming.
Where is AC transmission and DC transmission used?. This can also be a point of difference.
That’s a great observation.
Thanks, Deepali, for your comment. I have added this point.