30-05-2012, 02:06 PM
Flexible AC Transmission Systems
[attachment=23539]
FACTS-
In general, flexible AC transmission system (FACTS) is a new technology.
It has principal role of enhancing controllability and power transfer capability in ac system.
FACTS are a family of devices which can be inserted into power grid in series, in shunt, and in some cases, both in series and shunt.
With the increasing in demand of power, the power system networks are becoming more complex fron the point of view of operation and control.
Lots of research has gone into developing new technologies over the past few years to gain increased efficiency from the exciting power system.
Objectives for FACTS-
FACTS technology opens up new opportunities for controlling power and enhancing the usable capacity of present, as well as new and upgraded, lines.
Microelectronics, computers and high speed communications are widely used for protection and control of transmission systems.
The new technologies employ high speed thyristors for switching in or out transmission line component such as capacitors, reactors or phase shifting transformer for some desirable performance of the system.
Basic types of FACTS controllers-
FACTS controller is a power electronics-based system or other static equipment that provides control of one or more AC transmission system parameters. In general, FACTS controllers can be divided into four categories:
Series controllers
Shunt controllers
Combined series-series controllers
Combined series-shunt controllers
Shunt controllers-
A shunt controller is shown in figure ‘c’.
It may be a variable impedance, variable source, or a combination of these.
In principle, all shunt controllers inject current into the system at the point of connection.
Series Capacitors (SC)-
a series capacitor is not just a capacitor in series with the line. For proper functioning, series compensation requires control, protection and supervision facilities to enable it to perform as an integrated part of a power system.
The main protective device is a varistor, usually of ZnO type, limiting the voltage across the capacitor to safe values in conjunction with system faults giving rise to large short circuit currents flowing through the line.
[attachment=23539]
FACTS-
In general, flexible AC transmission system (FACTS) is a new technology.
It has principal role of enhancing controllability and power transfer capability in ac system.
FACTS are a family of devices which can be inserted into power grid in series, in shunt, and in some cases, both in series and shunt.
With the increasing in demand of power, the power system networks are becoming more complex fron the point of view of operation and control.
Lots of research has gone into developing new technologies over the past few years to gain increased efficiency from the exciting power system.
Objectives for FACTS-
FACTS technology opens up new opportunities for controlling power and enhancing the usable capacity of present, as well as new and upgraded, lines.
Microelectronics, computers and high speed communications are widely used for protection and control of transmission systems.
The new technologies employ high speed thyristors for switching in or out transmission line component such as capacitors, reactors or phase shifting transformer for some desirable performance of the system.
Basic types of FACTS controllers-
FACTS controller is a power electronics-based system or other static equipment that provides control of one or more AC transmission system parameters. In general, FACTS controllers can be divided into four categories:
Series controllers
Shunt controllers
Combined series-series controllers
Combined series-shunt controllers
Shunt controllers-
A shunt controller is shown in figure ‘c’.
It may be a variable impedance, variable source, or a combination of these.
In principle, all shunt controllers inject current into the system at the point of connection.
Series Capacitors (SC)-
a series capacitor is not just a capacitor in series with the line. For proper functioning, series compensation requires control, protection and supervision facilities to enable it to perform as an integrated part of a power system.
The main protective device is a varistor, usually of ZnO type, limiting the voltage across the capacitor to safe values in conjunction with system faults giving rise to large short circuit currents flowing through the line.