https://www.youtube.com/watch?v=SISRBhFD3ec Unified power flow controller (UPFC)

1. Unified Power Flow
Controller (UPFC)

2. • UPFC stands for Unified Power Flow Controller.
• UPFC can control both active and reactive power
flows in transmission system.
• UPFC uses solid state devices.
• UPFC is a combination of STATCOM (shunt) and
SSSC (series) coupled common voltage DC link.
• It was invented for real time control and dynamic
compensation of AC transmission system.
• UPFC can control simultaneously or selectively
voltage impedance phase angle in transmission line
and hence it is called UNIFIED.
• UPFC is a generalized synchronous voltage source
(SVS).

3. • UPFC consists of two back to back voltage source
converter operated by common dc link dc storage
capacitor.
• The function of converter 1 is to supply or absorb
real power demanded by converter 2.
• Converter 1 can be operated by unity power factor.
• Reactive power of converter 1 and converter 2 is
independent of each other.
• Because no reactive power flow through dc link.
• The UPFC can operate only under balanced sine
wave condition.