4-2
Protection and Control
BE1-951
D 1
SG0
S G 1
S G 3
D 0
D 2
D 3
A U T O
S E T T I N G
G R O U P
L O G I C
S L - G R O U P
M o d e =
0-disable
1-discrete select
2-binary select
S G 2
D2840-21.vsd
05-28-99
Figure 4-1. Setting Group Control Logic Block
by eliminating compromises in coordination settings
with adaptive setting groups is endless. Figure 4-1
shows the setting group control logic block.
The group of settings that are active at any point in time
is controlled by the setting group control logic. This
function logic allows for manual (logic) control. The
function monitors logic inputs, D0, D1, D2, and D3 and
changes the active setting group according to the status
of these inputs. These inputs can be connected to logic
expressions such as contact sensing inputs.
The function logic has four logic variable outputs, SG0,
SG1, SG2, and SG3. The appropriate variable is
asserted when each setting group is active. These logic
variables can be used in programmable logic to modify
the logic based upon which setting group is active. For example, it may be desirable for the 51P element
to trip the low-side breaker through OUT2 under normal conditions, but to trip the 86T lockout relay through
OUT1 when in setting group 3. To accomplish this, the logic for OUT1 would include the term 51PT
9
SG3
so that 51PT actuates only when SG3 is active.
The setting group control function logic also has an alarm output variable SGC (Setting Group Changed).
This output is asserted whenever the BE1-951 switches from one setting group to another. The SGC alarm
bit is asserted for the SGCON time setting. This output can be used in the programmable alarms function
if it is desired to monitor when the BE1-951 changes to a new setting group. See Section 6, Reporting and
Alarms Functions, Alarms Function for more information on using alarm outputs.
The SGCON time setting also serves to provide anti-pump protection to prevent excessive changing
between groups. Once a change in active group has been made, another change cannot take place for two
times the SGCON setting.
The SGC ACTIVE alarm output is typically used to provide an external acknowledgment that a setting group
change occurred. If SCADA is used to change the active group, then this signal could be monitored to verify
that the operation occurred. The SGC ACTIVE alarm output ON time is user programmable and should be
set greater than the SCADA scan rate. This can be set through the ASCII command interface by using the
SG-SGCON (settings general–SGC Alarm on time) command.
Table 4-1. Setting Group Control Function Settings
Setting
Range
Increment
Unit of Measure
Default
Alarm On Time
1 - 10 (0 = disabled)
1
Seconds
5
SG-SGCON Command
Purpose:
Read/Set SGC output on time
Syntax:
SG-SGCON[=<time>]
SG-SGCON Command Example
1.
Set the SGC alarm output to pulse ON/TRUE for 1 sec. after a the setting group is changed.
>SG-SGCON=1
When the BE1-951 switches to a new setting group, all functions are reset and initialized with the new
operating parameters. The settings change occurs instantaneously so at no time is the BE1-951 off line. The
active setting group is saved in non-volatile memory so that the BE1-951 will power up using the same
setting group that was used when it was powered down. To prevent the BE1-951 from changing settings
while a fault condition is in process, setting group changes are blocked when the BE1-951 is in a picked-up
state. Since the BE1-951 is completely programmable, the fault condition is defined by the pickup logic
expression in the fault reporting functions. See Section 6, Reporting and Alarm Functions, Fault Reporting
for more information.
