GE Industrial Solutions Entellisys System User Manual - Manual (Page 85)

85
6
6 Zones, buses, and topologies
6.0.1 Overview
6.0.1.1 Zones and buses
Entellisys implements Multi-Source Ground Fault (MSGF), Bus Differential (BD), and Zone
Selective Interlock (ZSI) as zone functions. In Entellisys, a zone is a set of circuit breakers
connected to a common bus. The circuit breakers in a zone may control the power to that bus
(e.g., a main circuit breaker), or the circuit breakers may be fed by that bus (e.g., a feeder or
sub-feeder).
The system is divided into zones to provide better performance and simplify the configuration.
MSGF, BD and ZSI will respond to faults that are within their zone and ignore faults outside the
zone. This allows the zones to be inherently selective with the other zones and individual circuit
breaker protection functions.
The system in Figure 6-1 contains two zones: Zone 1 is made up of Main 1 (M1), Tie 1 (T1), Feeder
Left 1 (FL1) and Feeder Left 2 (FL2). Zone 2 is made up of Main 2 (M2), Tie 1 (T1), Feeder Right 1
(FR1) and Feeder Right 2 (FR2). It also contains two buses, Bus 1 and Bus 2, separated by a tie
circuit breaker.
Figure 6-1 One-Line diagram for a main-tie-main system
The main-tie-main is a common configuration, but the concept of buses and zones is not limited
to a main-tie-main configuration. Entellisys only requires that the number of zones is between
one and four, and the number of circuit breakers per zone is between one and thirty (or zero if a
zone is not used).