Fundamental Frequency Equivalenting Of

This paper studies the issues of apparent fault loop impedance seen by distance relays protecting a series compensated line with Series Capacitors (SCs) and their Metal-Oxide Varistors (MOVs) installed in the middle of the line. In this paper, SCs&MOVs schemes are equivalented for the fundamental frequency and taken into account in the measurement of the fault loop impedance. Two different approaches to the equivalenting are considered and compared — the analytical approach, and the simulation (ATP-EMTP) oriented method. The equivalenting with the use of ATP-EMTP is recommended for further application. As a result of extensive simulation studies the two conditional impedances of the fault loop: without, and with compensation for the SC&MOV equivalent have been analyzed and proposed for the relaying purposes.