DPFC control during shunt converter failure

Distributed power flow controller (DPFC) is a new device within the family of FACTS. The DPFC has the same control capability as the UPFC, however at much lower cost and with a higher reliability. The reliability of the DPFC is given by the redundancy of multiple series converters. The shunt converter is the bottleneck for remaining reliability, because there is only one shunt converter in a DPFC system. During the shunt converter failure, the DPFC continues to work as controlled impedance, and only control the active power flow through the line. This paper presents a control of the DPFC, which keeps the DPFC system stable during the shunt converter failure. Adapted control schemes are employed to every series converters, which can automatically switch the series converter between the full-control mode and limited-control mode.With the adapted control, the reliability of the whole DFPC system is further improved. The adapted control scheme is verified both by simulation and experiment.