24-11-2012, 12:02 PM
FACTS Flexible AC Transmission System
[attachment=40934]
Characteristics of Transmission
Bottlenecks
• Steady-State Power Transfer Limit
• Voltage Stability Limit
• Transient Stability Limit
• Thermal Limit
• Short-Circuit Current Limit
FACTS
AC transmission systems incorporating the
power electronic-based to enhance
controllability and increase power transfer
capability.
FACTS Controllers
A power electronic based system & other
static equipment that provide control of one
or more AC transmission parameters
Line-Commutated
• Thyristors
• Electrically Triggered (ETT)
• Light Triggered (LTT)
Self-Commutated
• Gate-Turn Off Thyristors (GTO)
• Insulated Gate Bipolar Transistors (IGBTs)
• Integrated Gate Commutated Thyristors (IGCTs)
Thyristor Controlled Reactor (TCR)
Parallel-connected static var generator or
absorber
● Output is adjusted to exchange capacitive or
inductive current
● Maintain or control specific parameters of the
electrical power system
(typically bus voltage).
● Thyristor-based Controllers
● Lower cost alternative to STATCOM
Advantages of HVDC
• No limits in transmitted distance.
• Fast control of power flow, which implies stability
improvements.
• Direction of power flow can be changed very quickly.
• HVDC can carry more power for a given size of conductor
• improved transient stability
• dynamic damping of the electric system oscillations
• Require less space compared to ac for same voltage rating
and size
• Ground can be used as a return conductor
• No charging current
• HVDC transmission limits short circuit currents
[attachment=40934]
Characteristics of Transmission
Bottlenecks
• Steady-State Power Transfer Limit
• Voltage Stability Limit
• Transient Stability Limit
• Thermal Limit
• Short-Circuit Current Limit
FACTS
AC transmission systems incorporating the
power electronic-based to enhance
controllability and increase power transfer
capability.
FACTS Controllers
A power electronic based system & other
static equipment that provide control of one
or more AC transmission parameters
Line-Commutated
• Thyristors
• Electrically Triggered (ETT)
• Light Triggered (LTT)
Self-Commutated
• Gate-Turn Off Thyristors (GTO)
• Insulated Gate Bipolar Transistors (IGBTs)
• Integrated Gate Commutated Thyristors (IGCTs)
Thyristor Controlled Reactor (TCR)
Parallel-connected static var generator or
absorber
● Output is adjusted to exchange capacitive or
inductive current
● Maintain or control specific parameters of the
electrical power system
(typically bus voltage).
● Thyristor-based Controllers
● Lower cost alternative to STATCOM
Advantages of HVDC
• No limits in transmitted distance.
• Fast control of power flow, which implies stability
improvements.
• Direction of power flow can be changed very quickly.
• HVDC can carry more power for a given size of conductor
• improved transient stability
• dynamic damping of the electric system oscillations
• Require less space compared to ac for same voltage rating
and size
• Ground can be used as a return conductor
• No charging current
• HVDC transmission limits short circuit currents