8.4.4.5.2 Three Terminal Systems
If the differential current is greater that 1 AMP, the resulting differential current value may indicate which relay is
incorrectly wired.
If all three relays are wired correctly then the sum of the currents going into the local
and remote 2 relays will be
the same as the current going out of the remote 1 relay
as shown in Figure 8-9, and the differential current on
Phase A will be zero.
Station A
Station B
Communication
Channels
RFL 9300
Three
Terminal
RFL 9300
Three
Terminal
Local
Remote 1
2 Am
s
5 Amps
RFL 9300
Three
Terminal
Station C
Remote 2
3 Amps
Figure 8-9. Correctly wired three-terminal system
RFL 9300 RFL Electronics Inc.
October 20, 2004 8 - 33 (973) 334-3100