Basler Electric BE1-700 - Manual (Page 218)

lockout to reset (Input 1), is used to automatically reset the BE1-700V targets and Trip LED via Alogic@
input to the Target Reset Logic. See Figure 6-14, Target Reset Logic, Section 6, Reporting and Alarm
Functions.
Circuit Level Application - Manual and Auto Reclosing
The following logic was designed to work with the preprogrammed logic for the BE1-700V.
For the Bus Application, load restoration was accomplished by resetting the lockout relays (86UFs) and
allowing the circuit reclosing relays to close the breaker and restore load. Using the Circuit Level
Application, restoration can be accomplished by an automatic or manual closure of the breaker. Both
methods are described in the following paragraphs.
Referring to Figure 8-14, if sensing voltage is above the inhibit setting of the underfrequency elements 81
and 181T and system frequency is below the 81 and 181T setting, VO6, UF_TRIP goes high. This
initiates the auto reclose sequence through VO8, RI and forces VO13 (UF_LO) high, closing and sealing
the inputs to VO1 and VO3 through AND gate VO14 (LATCH). This allows the contacts of Output 3 and
Output 4 to transition and remain in that state, simulating
Aa@ and Ab@ contacts of an electrical reset
lockout relay (86). The VO14 seal also removes the block input from the 281 and 381T overfrequency
elements and either drives the 79 element to lockout (manual close) or puts a
Await@ on 79 (auto close).
The associated breaker will be tripped by Output 1 and the close circuit is disabled by Output 3.
When the load condition that initiated the event has subsided, the system operator/dispatcher will initiate
a remote restoration procedure. A
Arestoration permissive@ from the BE1-700 verifies that the following
conditions are met prior to allowing closure of the breaker:
• Underfrequency trip, 81T and 181T are no longer present.
• System frequency and voltage above the predetermined restore level (281 and 381T).
• The breaker is open.
• The VO14 latch circuit is high.
With VO7, PROT_RES high and the above conditions met, closure of the SCADA Restore contact forces
VO10, REST_PER high, breaking the VO13/VO14 seal and resetting Output Contacts 1 and 3. If
automatic reclosing is used, the
AWAIT@ input is removed and the reclosing element (79) closes the
breaker after a predetermined time delay. If manual reclosing is used, the ADTL/BLK@ input is removed
and the breaker is ready to close SCADA or local close.
As with the Bus Level Application, an optional Aauto target reset circuit@ can be initiated, automatically
resetting the BE1-700 targets and Trip LED and eliminating the need for further operator input. A one-
shot, non-retriggerable timer (62) initiated by VO10, REST_PER, is used to automatically reset the BE1-
700 targets and Trip LED via
Alogic@ input to the Target Reset Logic. See Figure 6-11, Target Reset Logic,
Section 6, Reporting and Alarms, Fault Reporting.
Logic Equations and Settings, Underfrequency Load Shedding
Bus UF Load Shed
The following is an example of how to apply UF Load Shed logic at the Bus level. The logic can be
applied in any number of ways including stand alone, to other preprogrammed schemes or completely
customized by the user. Using BESTCOMS to modify and add to the logic is not only quick and easy but
minimizes Input/Output
Aname@ and Astate@ label changes. In this example, start with a renamed version
of the BESTCOMS BUS logic scheme modified as follows:
SL-101=0
SL-V01=VO11*SG0
SN-IN1=UF-RESTORE,CLOSE,OPEN
Add the following UF logic to the modified BUS Logic Scheme:
SL-62=2, /IN1,0 (optional target reset)
SL-081=1,O
SL-181=1,O
SL-281=1,VO7
SL-381=1,VO7
SL-VO2=VO6
8-36 BE1-700 Application 9376700990 Rev M