Basler Electric BE1-851 - Manual (Page 174)

cause the recloser to be in lockout. When the breaker is manually closed, the relay will time out to a reset
condition.
Drive to lockout also occurs if any of the 150TP/N/Q functions (typically used for high set instantaneous
protection) trip or a breaker failure occurs. It should be noted that the 150TP/N/Q functions drive both the
RI and the DTL inputs to the recloser function block. The DTL input takes priority over the RI input.
Setting an appropriate logic expression for 79ZONE can enable zone-sequence coordination. Zone-
sequence uses a BESTlogic expression but is not within the logic settings. The Feeder_2 logic scheme
uses the expression SP-79ZONE=VO12.
Feeder_2 logic provides for the recloser to torque control the 50TP/N/Q functions (typically used for low
set instantaneous protection) during various steps in the reclosing sequence. Setting the recloser
sequence controlled blocking output in the four setting groups is done using the S#-79SCB command.
Recloser timing is stopped by the wait input if an overcurrent protection function block is picked up and
timing. This prevents the reset timer from resetting the reclose function for a situation where a 51 element
is just above pickup and the time to trip is longer than the reset time.
Initiation of the recloser function block by external relays is not accommodated in this scheme. IN2, IN3,
or IN4 can be reprogrammed to provide this function if desired.
A block load tap changer output is not provided in this scheme. OUT5 can be reprogrammed as a 79RNG
(recloser running/block tap changer) output and wired to energized normally closed auxiliary relay.
Normal Operation - Setting Group Selection
Setting group selection can be done automatically or externally by communications command/HMI
override. Automatic setting group changes for cold load pickup and/or dynamic setting adjustments are
enabled by SP-GROUP# commands. Setting group changes initiated by contact sensing inputs are not
accommodated in this scheme. IN2, IN3, or IN4 can be reprogrammed to provide this function if desired.
Virtual Switch 43 can disable the automatic change logic.
Normal Operation - Bus Protection
When any of the overcurrent function blocks are picked up, OUT4 closes. The signal from OUT4 is wired
to IN2 of the upstream relay using BUS logic. The upstream relay blocks the 50T elements that are set up
to trip the bus breaker or bus lockout relay. If the fault is not on a feeder, the 50T elements of the bus
relay are not blocked. The bus relay 50T elements are set with a time delay of 2 to 4 cycles to provide a
minimal coordination interval for the feeder relay OUT4 to close. Should there be a problem with the
blocking logic, the bus relay 51 functions are not blocked to allow bus fault clearing with a traditional
coordination interval.
Normal Operation - Alarms
Two alarm logic variables drive the front panel alarm LEDs: Major alarm (ALMMAJ) and Minor alarm
(ALMMIN). ALMMAJ is set to drive the fail-safe output OUTA. ALMMIN is not set to drive an output relay.
The logic can be modified to place ALMMIN in the BESTlogic expression for VOA if all alarms are to be
combined. ALMMIN can be placed in the BESTlogic expression for another output if it is desired that
these conditions be enunciated separately.
Contingency Operation - Test Mode
The test mode is intended to increase the security of the feeder protection and control system if external
test switches are not installed on all outputs. When the relay is out of service for testing, the breaker
failure, automatic reclosing, and block upstream instantaneous functions are disabled. Backup by the
upstream relay is enabled.
De-energizing IN4 or closing Virtual Switch 343 will put the logic scheme in the test mode. IN4 can be
controlled by a panel mounted selector switch that is closed in the normal state and open in the test state.
IN4 can also be controlled by a pole of a standard external test switch that is opened with the rest of the
test switch poles.
The logic expression for test mode drives virtual output 15 (VO15). This virtual output is alarm bit #23 in
the programmable alarm mask. It can be masked to drive an alarm LED to provide indication when the
relay is in test mode.
8-18 BE1-851 Application 9289900990 Rev R