Flexible ac transmission system advantages and disadvantages
Answers
A flexible alternating current transmission system or FACTS is a system which is composed of static equipment used for the AC transmission of electrical energy. Its purpose is to enhance controllability and increase power transfer capability of the network. Generally, it is a power electronics based system.
Advantages
1. FACTS increase the reliability of AC grids.
2. They reduce power delivery costs.
3. They supply inductive or reactive power to the grid and improve transmission quality and efficiency of power transmission.
4. There is fast voltage regulation.
5. Increased power transfer over long AC lines.
Disadvantages
1. A limited amount of power can be sent over a transmission line.
2. Conductors and equipment may be damaged by overheating if too much current is drawn.
3. The power flowing over an AC line is proportional to the sine of the phase angle of the voltage at the receiving and transmitting ends. This angle varies depending on the system loading and generation and an angle of 90 degrees is not suitable.
A Flexible AC Transmission System is used when the power factor must be unity. In other words, these systems are used when the active power must be equal to the apparent power. The following are some advantages and disadvantages of such systems.
Advantages:
*Capable of transferring very high power
*Very high controllability
Disadvantages:
*Transmits only limited amount of power
*Non-linear in nature and produce harmonics in the output signal