Basler Electric BE1-851 - Manual (Page 183)

Reclosing can be disabled by IN2 or Virtual Switch 143 that is connected to the drive to lockout (DTL)
input of the recloser function block. In this scheme, enabling the recloser after a “one shot” trip will cause
the recloser to be in lockout. Once the breaker is manually closed, the recloser will time out to a reset
condition. If an external control switch slip contact is used, it should be wired in series with the reclose
enable switch to IN2.
The BESTlogic can be modified so that the reclosing disable logic interrupts the RI input to the recloser
instead of driving the recloser to lockout. This is accomplished by using variables IN2, 143, and 101SC in
the RI expression instead of the DTL expression. This recloser control logic is used in preprogrammed
logic scheme Feeder_4.
Drive to lockout also occurs if any of the 150TP/N/Q functions (typically used for high set instantaneous
protection) trip or 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_3 logic scheme
uses the expression SP-79ZONE=VO12.
Feeder_3 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.
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 energize a 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. IN3 or IN4 can be reprogrammed to provide this function instead of their
programmed functions 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.
When used to provide high-speed overcurrent protection for the substation bus, it is recommended that all
51 function timing curves be set for instantaneous reset.
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 in 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
9289900990 Rev R BE1-851 Application 8-27