Converter rating powers of unified power flow controller

Converter loadings of a unified power flow controller (UPFC) within alleviation of voltage stability problem represents the main concern of this paper. The UPFC is analysed as the device, which provides voltage support and/or co-ordinating power flow control action. The voltage stability problem is viewed from longer-term time domain response of a dynamic load model with nonlinear recovery. First, the optimal rating algorithm is addressed from a viewpoint of series power flow control as an initial estimate of the UPFC converter ratings. Then, further thorough analysis is employed should other operational aspects (e.g. damping and voltage support) be concerned. Computational procedure reveals a necessity to increase converter rating powers within dynamic voltage collapse scenario.