Relay coordination with multiple breaker-in/breaker-out stations on the transmission line

The main purpose of power system protection is to remove faults from the system as soon as possible so minimum damage happens to the transmission line or other equipment connected to the line. Tennessee Valley Authority (TVA) planners want to add multiple breaker-in/breaker-out stations on a two terminal transmission lines to reduce the number of Customer Connection Point Interruption (CCPI). This paper discusses the difficulty of setting up the zone distance relays and overcurrent relays when multiple breaker-in/breaker-out stations are added on the transmission line. It explains how many breakers can safely be added without compromising the zone 2 time delay of 50 cycles (limit imposed by TVA), how to set distance relay for phase faults and instantaneous overcurrent as well as time overcurrent relay for ground fault. It makes recommendation for not placing the breaker-in/breaker-out stations at a certain distance on transmission line and also talks about the maximum line loadability according to NERC standard PRC-023 when zone 2 of the distance element is set higher than 130%