A new concept of exchanging active power without common DC link for Interline Power Flow Controller (S-IPFC)

The separated interline power flow controller (S-IPFC) presented is a new concept for a FACTS device. The S-IPFC is an adapted version of the IPFC, which eliminates the common dc link of the IPFC and enable the separate installation of the converters. Without location constrain, more power lines can be equipped with the S-IPFC, which gives more control capability of the power flow control. Instead of the common dc link, the exchange active power between the converters is through the same ac transmission line at 3rd harmonic frequency. Every converter has its own dc capacitor to provide the dc voltage. This paper presents the basis theory of the S-IPFC, steady-state analysis, primary control loop and the corresponding simulation results.