LAUSR

Power swing blocker (PSB) is a complementary part in distance relay that detects power swing. Unified power flow controller (UPFC) is also used in a transmission line to control active and reactive power. The UPFC operation during power swing influences the performance of PSBs in different ways. In this paper, 4 PSB methods are programmed, and their indices are analyzed in UPFC-compensated line. The methods based on (1) rate of change of power and (2) fundamental frequency of instantaneous 3-phase active power are used to show the influence of nontransient response of UPFC. The method based on rate of change of impedance is used to show the influence of transient response of UPFC. Method based on transient monitor is used to show the impact of electrical part of UPFC. Indices of these methods are examined in compensated condition, and it is shown that indices may no longer work.