GE Industrial Solutions Entellisys 5.0 User Manual - Manual (Page 143)

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8 Reduced Energy Let-Thru Mode
Reduced energy let-thru (RELT) is an optional feature which provides the ability for a user to
quickly adjust the system to temporary settings (usually more sensitive) while in close proximity
to the Entellisys switchgear or downstream equipment.
Topology 0 stores RELT settings for each relay (see below). Topology 0 settings will take
precedence over any topologies until the system is returned to normal.
Highlights
• Reduces potential arc flash energy - Increases the sensitivity of the breaker, potentially
lowering the HRC category.
• Dynamic ZSI Automatic Adjustment - Breakers in RELT mode will use their RELT settings.
ZSI delays will dynamically adjust all upstream breakers.
• Security - Individual user software “keys” are used to track RELT commands per user.
• Easy to use - Quickly enable, disable and view RELT with clear graphics on an intuitive
HMI touchscreen interface.
• Programmable - RELT can be turned on and off via Modbus TCP, FlexLogic or from an
external device through Discrete I/O.
• Flexibility - RELT for a single breaker, group of breakers or the entire lineup can be
executed by a single user input.
• Alarming - A Reduced Energy Let-Thru Mode alarm is available for visual and email
notification.
Relays with RELT Settings
Single-point Relays
• Overcurrent relays - IOC, ST, LT and GF
Multi-point Relays
• Bus Differential (BD)
• Multi-Source Ground Fault (MSGF)
• Dynamic Zone Selective Interlock (ZSI)
• High Resistance Ground Fault (HRGF) Priority Tripping
Reduced Energy Let - Thru Modes
• Single Breaker RELT - Switches overcurrent relay settings to RELT (Topology 0) for a single
breaker as well as any associated breakers as a group. (See RELT Groups on page 144 )
• Multi-point RELT - This will add a “Multi-point” key and switch all multi-point relays to
RELT (Topology 0) settings as a group.
• System Wide RELT - This will add a “System Wide” key and switch settings for all current
relays on all breakers as well as all multi-point relays to RELT (Topology 0) settings.