Basler Electric BE1-851 - Manual (Page 158)

Overview of Preprogrammed Logic Schemes
There are six preprogrammed logic schemes available. Four logic schemes are intended for use on
feeder breakers. Two schemes are intended for use on the bus main breaker. This is typically the low-
side bank breaker of the step-down power transformer.
Factory Default Logic Settings
BE1-851 relays are shipped from the factory with default logic settings that are designed to allow the relay
to be used directly in applications that do not require any of the relays advanced features. These default
settings provide a basic overcurrent protection scheme. The default setting for the logic scheme name is
“USER”. This scheme can be modified as outlined in Section 7, BESTlogic Programmable Logic, Logic
Schemes. However, if you choose to change these settings, the defaults can only be brought back
through BESTCOMS™, manual programming, or by reloading the entire factory defaults.
Feeder_1 Logic Scheme
This logic scheme provides time and instantaneous overcurrent protection. Breaker failure protection is
also included. Functions such as manual control and automatic reclosing are not included. Logic is
provided to maintain feeder protection when the relay is out of service. A bus relay using the
preprogrammed logic scheme BACKUP will be signaled to continue protection.
Feeder_2 Logic Scheme
This logic scheme provides time and both high set and low set instantaneous overcurrent protection.
Automatic reclosing is included with reclosing initiated by a protective trip (reclose initiate scheme).
Breaker Failure and manual control functions are also included. Logic is included to signal a bus relay
using the preprogrammed logic scheme BACKUP to provide feeder protection when the relay is out of
service. This scheme is not provided when style option 1 is V or W.
Feeder_3 Logic Scheme
This logic scheme provides time and both high set and low set instantaneous overcurrent protection.
Automatic reclosing is included. Reclosing is initiated when the breaker opens. Reclosing is disabled after
a manual trip by a control switch slip contact. Driving the recloser to lockout disables the recloser. Breaker
Failure and manual control functions are also provided. Logic is included to signal a bus relay using
preprogrammed logic scheme BACKUP to provide feeder protection when the relay is out of service. This
scheme is not provided when style option 1 is V or W.
Feeder_4 Logic Scheme
This logic scheme provides time and instantaneous overcurrent protection. Automatic reclosing is
included. Reclosing is initiated when the breaker opens. Interrupting the reclose initiate input disables the
recloser. Reclosing is disabled after a manual trip by a control switch slip contact. Breaker Failure and
manual control functions are also included. Backup for an out of service relay is to be provided by
redundant relays on the feeder breaker. Logic is included to interconnect with the redundant relays for an
external breaker failure initiate and blocking of the external instantaneous. This scheme is not provided
when style option 1 is V or W.
BUS Logic Scheme
This logic scheme is applied to a bus main relay to provide primary bus overcurrent protection. It contains
logic to interconnect with the feeder logic schemes to provide high-speed overcurrent protection for the
bus under normal conditions. It also contains logic to trip the feeder breakers while the feeder relays using
Feeder_1, Feeder_2, or Feeder_3 logic schemes are out of service. This scheme is not provided when
style option 1 is V or W.
BACKUP Logic Schemes
This logic scheme is applied to a bus main relay to provide backup bus overcurrent protection as well as
breaker failure protection for the bus breaker under normal conditions. It also provides primary bus
overcurrent protection when the relay using BUS logic is providing feeder protection or when the primary
bus relay is out of service. This scheme is not provided when style option 1 is V or W.
8-2 BE1-851 Application 9289900990 Rev R