FACTS Devices
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system.
FACTS is defined by the IEEE as "a power electronic based system and other static equipment that provide control of one or more AC transmission system parameters to enhance controllability and
Technology
Transmission on a no-loss line.
Series compensation.
Shunt compensation.
History
The first FACTS installation was at the C. J. Slatt Substation in Northern Oregon. This is a 500 kV, 3-phase 60 Hz substation, and was developed by EPRI, the Bonneville P
Series compensation
In series compensation, the FACTS is connected in series with the power system. It works as a controllable voltage source. Seriesinductance exists in all AC transmission lines. On long lines, when a large current flows, this causes a large voltage drop. To compensate, series capacitors are connected, decreasing the effect of the inductance.
Shunt compensation
In shunt compensation, power system is connected in shunt (parallel) with the FACTS. It works as a controllable current source. Shunt compensation is of two types:
Shunt capacitive compensation
This method is used to improve the power factor. Whenever an inductive load is connected to the transmission line, power factor lags because of lagging load current. To compensate, a shunt capacitor is connected which draws current leading the source voltage. The net result is improvement in power factor.
Shunt inductive compensation
This method is used either when charging the transmission line, or, when there is very low load at the receiving end. Due to very low, or no load – very low current flows through the transmission line. Shunt capacitance in the transmission line causes voltage amplification (Ferranti Effect). The
FACTS is defined by the IEEE as "a power electronic based system and other static equipment that provide control of one or more AC transmission system parameters to enhance controllability and
Technology
Transmission on a no-loss line.
Series compensation.
Shunt compensation.
History
The first FACTS installation was at the C. J. Slatt Substation in Northern Oregon. This is a 500 kV, 3-phase 60 Hz substation, and was developed by EPRI, the Bonneville P
Series compensation
In series compensation, the FACTS is connected in series with the power system. It works as a controllable voltage source. Seriesinductance exists in all AC transmission lines. On long lines, when a large current flows, this causes a large voltage drop. To compensate, series capacitors are connected, decreasing the effect of the inductance.
Shunt compensation
In shunt compensation, power system is connected in shunt (parallel) with the FACTS. It works as a controllable current source. Shunt compensation is of two types:
Shunt capacitive compensation
This method is used to improve the power factor. Whenever an inductive load is connected to the transmission line, power factor lags because of lagging load current. To compensate, a shunt capacitor is connected which draws current leading the source voltage. The net result is improvement in power factor.
Shunt inductive compensation
This method is used either when charging the transmission line, or, when there is very low load at the receiving end. Due to very low, or no load – very low current flows through the transmission line. Shunt capacitance in the transmission line causes voltage amplification (Ferranti Effect). The