UPFC operating characteristics impact on transmission line distance protection

This paper presents the impact of unified power flow controller (UPFC) operating characteristics on the transmission line protective relay behavior. The impact of the series compensating part of UPFC, i.e., static synchronous series compensator (SSSC) and shunt compensating part, i.e., STATic COMpensator (STATCOM) on distance relay are analyzed individually and collectively. The simulations investigate the impact of series injected voltage magnitude and phase angle on the performance of a distance relay for different fault conditions. It is shown that the magnitude and phase angle of the series voltage injected by SSSC affects the distance relay operation more than the STATCOM for a specified fault.