H. Shateri, S. Jamali,
Volume 2, Issue 3 (7-2006)
Abstract
This paper presents the effects of instrument transformers connection points on
the measured impedance by distance relays in the presence of Flexible Alternating Current
Transmission System (FACTS) devices with series connected branch. Distance relay
tripping characteristic itself depends on the power system structural conditions, pre-fault
operational conditions, and especially the ground fault resistance. The structural and
controlling parameters of FACTS devices as well as the connection points of instrument
transformers affect the ideal tripping characteristic of distance relay. This paper presents a
general set of equations to evaluate the measured impedance at the relaying point for a
general model of FACTS devices to consider different affecting parameters.