Referring to Figure 4.10, there is more current in the relays at current breaker (CB) 5 with all
lines in service than there is with line 3–4 out of service (8.33 versus 5.88 A). This helps the
coordination between relays at CB 5 and relays at CB 1. With line 3–4 out of service, the infeed
is no longer present and the current decreases in the relays at CB 5 (8.33 to 5.88 A) and increases
in the relays at CB 1 (4.165 to 5.88 A). This is the critical case for coordination.